musl-cross-make / litecross improvements

musl-cross-make / litecross improvements

[Rich Felker]

I've made a number of improvements and fixes to musl-cross-make which
are in the upstream repo now, based on bug reports I got:

- Spurious dependency on flex (upstream's fault, worked around)
- Spurious dependency on texinfo (ditto)
- Ability to use pre-installed gmp/mpc/mpfr libs
- Config examples for static linking, no-debug builds.

https://github.com/richfelker/musl-cross-make

A few things I still plan to add at some point:

- Support for GCC 6, maybe older GCC's too
- Fixing configure bottlenecks with config.cache
- Getting "make check" working
- Automating multi-target builds
- Automating building binary static-linked-vs-musl toolchains

Let me know if any major bugs/inconveniences remain that I should
prioritize fixing.

Rich

Re: musl-cross-make / litecross improvements

[Szabolcs Nagy]

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* Rich Felker <dalias@libc.org> [2016-05-03 00:48:36 -0400]:
> I've made a number of improvements and fixes to musl-cross-make which
> are in the upstream repo now, based on bug reports I got:
> 
> - Spurious dependency on flex (upstream's fault, worked around)
> - Spurious dependency on texinfo (ditto)

gcc assumes you want to install info files if BUILD_INFO
is set, which is set based on MAKEINFO, however you cannot
override that, because the configure script will find a
working makeinfo if there is one on the system anyway..

explicit gcc_cv_prog_makeinfo_modern=no solves this in gcc
directories. (the man pages are still installed)

possibly make -o info -o install-info -o install-man
can do this too (havent tested).

> - Ability to use pre-installed gmp/mpc/mpfr libs
> - Config examples for static linking, no-debug builds.

this is not enough:
COMMON_CONFIG += CFLAGS="-g0 -Os" CXXFLAGS="-g0 -Os" LDFLAGS="-s"

target libs still have the full debug path in them,
for that you also need:
COMMON_CONFIG += CFLAGS_FOR_TARGET="-g0 -Os" CXXFLAGS_FOR_TARGET="-g0 -Os" LDFLAGS_FOR_TARGET="-s"

however libgcc seems to be built specially and -g
is always passed there (after CFLAGS_FOR_TARGET),
but one can drop the build path prefix by
COMMON_CONFIG += --with-debug-prefix-map=$(PWD)=

musl is built differently (LDFLAGS is needed because of libgcc):
MUSL_CONFIG += --disable-debug LDFLAGS=-s

i'm not sure if it's a good idea distributing the
toolchain without debug info, but this is needed
if you want to avoid leaking the build path.
the abs build path is still present in all the .la
and .a files and in
lib/gcc/x86_64-linux-musl/5.2.0/install-tools/mkheaders.conf
for me the host lib path managed to get into
lib64/libcc1.so.0.0.0 (via rpath).

> 
> https://github.com/richfelker/musl-cross-make
> 
> A few things I still plan to add at some point:
> 
> - Support for GCC 6, maybe older GCC's too
> - Fixing configure bottlenecks with config.cache
> - Getting "make check" working
> - Automating multi-target builds
> - Automating building binary static-linked-vs-musl toolchains
> 
> Let me know if any major bugs/inconveniences remain that I should
> prioritize fixing.

the target libs are installed under lib64/,
i think the usr/ and lib64/ symlinks are useful
(so it can be used as rootfs without fiddling
with etc/ld-musl*.path).

i think
GCC_CONFIG += --disable-gnu-indirect-function
is important, otherwise libatomic will be broken.

gcc-6 will need
GCC_CONFIG += --disable-libmpx

and libstdc++ only uses vdso clock_gettime
with --enable-libstdcxx-time

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diff --git a/litecross/Makefile b/litecross/Makefile
index fbabe4a..d2a7bce 100644
--- a/litecross/Makefile
+++ b/litecross/Makefile
@@ -17,6 +17,7 @@ MUSL_CONFIG = CC="$(XGCC)" LIBCC="../obj_toolchain/$(TARGET)/libgcc/libgcc.a" --
 
 MAKE += INFO_DEPS= infodir=
 MAKE += ac_cv_prog_lex_root=lex.yy.c
+MAKE += gcc_cv_prog_makeinfo_modern=no
 
 FULL_TOOLCHAIN_CONFIG = $(TOOLCHAIN_CONFIG) \
 	--disable-werror \
@@ -132,10 +133,16 @@ obj_toolchain/.lc_built: | obj_toolchain/.lc_configured obj_sysroot/.lc_libs
 	cd obj_toolchain && $(MAKE) MAKE="$(MAKE)" LC_ROOT=$(PWD)
 	touch $@
 
-install-musl: | obj_musl/.lc_built
+.lc_target_links:
+	mkdir -p $(DESTDIR)$(OUTPUT)/$(TARGET)
+	ln -sf . $(DESTDIR)$(OUTPUT)/$(TARGET)/usr
+	ln -sf lib $(DESTDIR)$(OUTPUT)/$(TARGET)/lib64
+	touch $@
+
+install-musl: | obj_musl/.lc_built .lc_target_links
 	cd obj_musl && $(MAKE) $(MUSL_VARS) DESTDIR=$(DESTDIR)$(OUTPUT)/$(TARGET) install
 
-install-toolchain: | obj_toolchain/.lc_built
+install-toolchain: | obj_toolchain/.lc_built .lc_target_links
 	cd obj_toolchain && $(MAKE) MAKE="$(MAKE)" LC_ROOT=$(PWD) DESTDIR=$(DESTDIR)$(OUTPUT) install
 
 endif

Re: musl-cross-make / litecross improvements

[Rich Felker]

On Tue, May 03, 2016 at 01:39:43PM +0200, Szabolcs Nagy wrote:
> * Rich Felker <dalias@libc.org> [2016-05-03 00:48:36 -0400]:
> > I've made a number of improvements and fixes to musl-cross-make which
> > are in the upstream repo now, based on bug reports I got:
> > 
> > - Spurious dependency on flex (upstream's fault, worked around)
> > - Spurious dependency on texinfo (ditto)
> 
> gcc assumes you want to install info files if BUILD_INFO
> is set, which is set based on MAKEINFO, however you cannot
> override that, because the configure script will find a
> working makeinfo if there is one on the system anyway..

I'd certainly like cleaner solutions to this problem if you have any.
Overriding these things as make variables is quite powerful and might
be able to do it.

> explicit gcc_cv_prog_makeinfo_modern=no solves this in gcc
> directories. (the man pages are still installed)

Yeah, it'd be nice to suppress them too, especially if they're
out of sync with the patched docs when makeinfo is unavailable.

> possibly make -o info -o install-info -o install-man
> can do this too (havent tested).

The -o approach only works when it's added to $(MAKE), because make
explicitly strips -o's from being passed down recursively in MAKEFLAGS
etc.

> > - Ability to use pre-installed gmp/mpc/mpfr libs
> > - Config examples for static linking, no-debug builds.
> 
> this is not enough:
> COMMON_CONFIG += CFLAGS="-g0 -Os" CXXFLAGS="-g0 -Os" LDFLAGS="-s"
> 
> target libs still have the full debug path in them,
> for that you also need:
> COMMON_CONFIG += CFLAGS_FOR_TARGET="-g0 -Os" CXXFLAGS_FOR_TARGET="-g0 -Os" LDFLAGS_FOR_TARGET="-s"

Generally you _do_ want debug info for target libs. If we want to keep
bogus paths linked to the build system out of it, gcc has an option to
fake these (strip a leading prefix) that we could use, I think.

Overall, I'm not trying to strip build system paths from a hard-core
privacy perspective because it seems too hard to do reliably. Users
who really want to do that can use a symlink under /tmp for the build
dir, I think. I mainly just want to avoid outwardly wrong behavior and
printing paths that don't make sense. But these are minor issues I
really don't want to spend time on since I have more productive things
to be doing. :-)

> i'm not sure if it's a good idea distributing the
> toolchain without debug info, but this is needed
> if you want to avoid leaking the build path.

It wouldn't hurt to dig up the gcc option to strip a prefix from the
debug paths and including an example of how to use it, in case users
want this.

> > Let me know if any major bugs/inconveniences remain that I should
> > prioritize fixing.
> 
> the target libs are installed under lib64/,
> i think the usr/ and lib64/ symlinks are useful
> (so it can be used as rootfs without fiddling
> with etc/ld-musl*.path).

Yes. Is there a good way to override that in gcc or should we just
make the symlinks?

> i think
> GCC_CONFIG += --disable-gnu-indirect-function
> is important, otherwise libatomic will be broken.

Bleh, this should really be in the musl support patches, but I'll just
add it here for now.

> gcc-6 will need
> GCC_CONFIG += --disable-libmpx

OK. Is that because their code is broken, or because of something on
musl's side? Is it detectable?

> and libstdc++ only uses vdso clock_gettime
> with --enable-libstdcxx-time

Is there a link to this issue? I don't mind adding it but I'd like to
know details.

> diff --git a/litecross/Makefile b/litecross/Makefile
> index fbabe4a..d2a7bce 100644
> --- a/litecross/Makefile
> +++ b/litecross/Makefile
> @@ -17,6 +17,7 @@ MUSL_CONFIG = CC="$(XGCC)" LIBCC="../obj_toolchain/$(TARGET)/libgcc/libgcc.a" --
>  
>  MAKE += INFO_DEPS= infodir=
>  MAKE += ac_cv_prog_lex_root=lex.yy.c
> +MAKE += gcc_cv_prog_makeinfo_modern=no

Does this make a difference?

>  FULL_TOOLCHAIN_CONFIG = $(TOOLCHAIN_CONFIG) \
>  	--disable-werror \
> @@ -132,10 +133,16 @@ obj_toolchain/.lc_built: | obj_toolchain/.lc_configured obj_sysroot/.lc_libs
>  	cd obj_toolchain && $(MAKE) MAKE="$(MAKE)" LC_ROOT=$(PWD)
>  	touch $@
>  
> -install-musl: | obj_musl/.lc_built
> +.lc_target_links:
> +	mkdir -p $(DESTDIR)$(OUTPUT)/$(TARGET)
> +	ln -sf . $(DESTDIR)$(OUTPUT)/$(TARGET)/usr
> +	ln -sf lib $(DESTDIR)$(OUTPUT)/$(TARGET)/lib64
> +	touch $@
> +

I think rather than using a stamp file we can just make lib64 itself a
target:

install-*: $(DESTDIR)$(OUTPUT)/$(TARGET)/lib64

$(DESTDIR)$(OUTPUT)/$(TARGET)/lib64:
	mkdir -p $(dir $@)
	mkdir -p $(patsubst %64,%,$@)
	ln -sf lib $@

or similar.

> +install-musl: | obj_musl/.lc_built .lc_target_links
>  	cd obj_musl && $(MAKE) $(MUSL_VARS) DESTDIR=$(DESTDIR)$(OUTPUT)/$(TARGET) install

Installation of musl doesn't seem to depend on the links; only gcc
does (because it installs stuff to lib64).

Rich

Re: musl-cross-make / litecross improvements

[Szabolcs Nagy]

* Rich Felker <dalias@libc.org> [2016-05-03 14:02:30 -0400]:
> On Tue, May 03, 2016 at 01:39:43PM +0200, Szabolcs Nagy wrote:
> > possibly make -o info -o install-info -o install-man
> > can do this too (havent tested).
> 
> The -o approach only works when it's added to $(MAKE), because make
> explicitly strips -o's from being passed down recursively in MAKEFLAGS
> etc.

we have to fiddle with MAKE anyway so probably this is
approach is cleaner.

maybe have a RECURSIVE_MAKEFLAGS or similar in toplevel
config.mak (with the caveat that it will be passed to
every make)

> > i'm not sure if it's a good idea distributing the
> > toolchain without debug info, but this is needed
> > if you want to avoid leaking the build path.
> 
> It wouldn't hurt to dig up the gcc option to strip a prefix from the
> debug paths and including an example of how to use it, in case users
> want this.
> 

COMMON_CONFIG += --with-debug-prefix-map=$(PWD)=

> > the target libs are installed under lib64/,
> > i think the usr/ and lib64/ symlinks are useful
> > (so it can be used as rootfs without fiddling
> > with etc/ld-musl*.path).
> 
> Yes. Is there a good way to override that in gcc or should we just
> make the symlinks?
> 

output/lib64 can be eliminated by
COMMON_CONFIG += --libdir=/lib

output/x86_64-linux-musl/lib64 install path is trickier:
it is controlled by the $toolexeclibdir make variable.
which is set according to $CC -print-multi-os-directory
which is controlled by multilib and multilib_defaults from
$CC -dumpspecs which comes from multilib.h generated by
genmultilib based on parameters from config/i386/t-linux64

> > gcc-6 will need
> > GCC_CONFIG += --disable-libmpx
> 
> OK. Is that because their code is broken, or because of something on
> musl's side? Is it detectable?
> 

the code is currently broken (missing includes and uses secure_getenv)

> > and libstdc++ only uses vdso clock_gettime
> > with --enable-libstdcxx-time
> 
> Is there a link to this issue? I don't mind adding it but I'd like to
> know details.

http://gcc.gnu.org/onlinedocs/libstdc++/manual/configure.html


> > diff --git a/litecross/Makefile b/litecross/Makefile
> > index fbabe4a..d2a7bce 100644
> > --- a/litecross/Makefile
> > +++ b/litecross/Makefile
> > @@ -17,6 +17,7 @@ MUSL_CONFIG = CC="$(XGCC)" LIBCC="../obj_toolchain/$(TARGET)/libgcc/libgcc.a" --
> >  
> >  MAKE += INFO_DEPS= infodir=
> >  MAKE += ac_cv_prog_lex_root=lex.yy.c
> > +MAKE += gcc_cv_prog_makeinfo_modern=no
> 
> Does this make a difference?

yes, gcc info files are not installed if it's set

Re: musl-cross-make / litecross improvements

[Szabolcs Nagy]

* Szabolcs Nagy <nsz@port70.net> [2016-05-03 22:16:22 +0200]:
> * Rich Felker <dalias@libc.org> [2016-05-03 14:02:30 -0400]:
> > On Tue, May 03, 2016 at 01:39:43PM +0200, Szabolcs Nagy wrote:
> > > i think the usr/ and lib64/ symlinks are useful
> > > (so it can be used as rootfs without fiddling
> > > with etc/ld-musl*.path).
> > 
> > Yes. Is there a good way to override that in gcc or should we just
> > make the symlinks?
> > 
> 
> output/lib64 can be eliminated by
> COMMON_CONFIG += --libdir=/lib
> 
> output/x86_64-linux-musl/lib64 install path is trickier:
> it is controlled by the $toolexeclibdir make variable.
> which is set according to $CC -print-multi-os-directory
> which is controlled by multilib and multilib_defaults from
> $CC -dumpspecs which comes from multilib.h generated by
> genmultilib based on parameters from config/i386/t-linux64
> 

it was not clear if the t-linux64 thing could be overridden, but

GCC_CONFIG += --with-multilib-list=

fixes it (the lib dir is lib/ then).

Re: musl-cross-make / litecross improvements

[Rich Felker]

On Tue, May 03, 2016 at 11:57:05PM +0200, Szabolcs Nagy wrote:
> * Szabolcs Nagy <nsz@port70.net> [2016-05-03 22:16:22 +0200]:
> > * Rich Felker <dalias@libc.org> [2016-05-03 14:02:30 -0400]:
> > > On Tue, May 03, 2016 at 01:39:43PM +0200, Szabolcs Nagy wrote:
> > > > i think the usr/ and lib64/ symlinks are useful
> > > > (so it can be used as rootfs without fiddling
> > > > with etc/ld-musl*.path).
> > > 
> > > Yes. Is there a good way to override that in gcc or should we just
> > > make the symlinks?
> > > 
> > 
> > output/lib64 can be eliminated by
> > COMMON_CONFIG += --libdir=/lib

This does not seem useful except for deuglifying; that dir is not part
of the target root.

> > output/x86_64-linux-musl/lib64 install path is trickier:
> > it is controlled by the $toolexeclibdir make variable.
> > which is set according to $CC -print-multi-os-directory
> > which is controlled by multilib and multilib_defaults from
> > $CC -dumpspecs which comes from multilib.h generated by
> > genmultilib based on parameters from config/i386/t-linux64
> 
> it was not clear if the t-linux64 thing could be overridden, but
> 
> GCC_CONFIG += --with-multilib-list=
> 
> fixes it (the lib dir is lib/ then).

I wonder if this works for all targets, and how it relates to
--disable-multilib. At least on sh4 if you disable multilib you need
to --enable-incomplete-targets because the kernel is built with
-m4-nofpu and gcc normally errors out when you pass that option and
the libs aren't built. I seem to recall multilib options being a mess
on some other archs too.

Rich

Re: musl-cross-make / litecross improvements

[Rich Felker]

On Tue, May 03, 2016 at 11:57:05PM +0200, Szabolcs Nagy wrote:
> * Szabolcs Nagy <nsz@port70.net> [2016-05-03 22:16:22 +0200]:
> > * Rich Felker <dalias@libc.org> [2016-05-03 14:02:30 -0400]:
> > > On Tue, May 03, 2016 at 01:39:43PM +0200, Szabolcs Nagy wrote:
> > > > i think the usr/ and lib64/ symlinks are useful
> > > > (so it can be used as rootfs without fiddling
> > > > with etc/ld-musl*.path).
> > > 
> > > Yes. Is there a good way to override that in gcc or should we just
> > > make the symlinks?
> > > 
> > 
> > output/lib64 can be eliminated by
> > COMMON_CONFIG += --libdir=/lib
> > 
> > output/x86_64-linux-musl/lib64 install path is trickier:
> > it is controlled by the $toolexeclibdir make variable.
> > which is set according to $CC -print-multi-os-directory
> > which is controlled by multilib and multilib_defaults from
> > $CC -dumpspecs which comes from multilib.h generated by
> > genmultilib based on parameters from config/i386/t-linux64
> > 
> 
> it was not clear if the t-linux64 thing could be overridden, but
> 
> GCC_CONFIG += --with-multilib-list=
> 
> fixes it (the lib dir is lib/ then).

Hmm, on x86_64 Alpine, gcc -print-multi-os-directory shows ../lib but
with -m32 it shows ../lib32. Does that mean there's some way to make
it behave sanely? Or are they just patching it?

Rich

Re: musl-cross-make / litecross improvements

[Szabolcs Nagy]

* Rich Felker <dalias@libc.org> [2016-05-03 23:53:44 -0400]:
> On Tue, May 03, 2016 at 11:57:05PM +0200, Szabolcs Nagy wrote:
> > * Szabolcs Nagy <nsz@port70.net> [2016-05-03 22:16:22 +0200]:
> > > * Rich Felker <dalias@libc.org> [2016-05-03 14:02:30 -0400]:
> > > > On Tue, May 03, 2016 at 01:39:43PM +0200, Szabolcs Nagy wrote:
> > > > > i think the usr/ and lib64/ symlinks are useful
> > > > > (so it can be used as rootfs without fiddling
> > > > > with etc/ld-musl*.path).
> > > > 
> > > > Yes. Is there a good way to override that in gcc or should we just
> > > > make the symlinks?
> > > > 
> > > 
> > > output/lib64 can be eliminated by
> > > COMMON_CONFIG += --libdir=/lib
> > > 
> > > output/x86_64-linux-musl/lib64 install path is trickier:
> > > it is controlled by the $toolexeclibdir make variable.
> > > which is set according to $CC -print-multi-os-directory
> > > which is controlled by multilib and multilib_defaults from
> > > $CC -dumpspecs which comes from multilib.h generated by
> > > genmultilib based on parameters from config/i386/t-linux64
> > > 
> > 
> > it was not clear if the t-linux64 thing could be overridden, but
> > 
> > GCC_CONFIG += --with-multilib-list=
> > 
> > fixes it (the lib dir is lib/ then).
> 
> Hmm, on x86_64 Alpine, gcc -print-multi-os-directory shows ../lib but
> with -m32 it shows ../lib32. Does that mean there's some way to make
> it behave sanely? Or are they just patching it?

http://git.alpinelinux.org/cgit/aports/plain/main/gcc/gcc-pure64.patch

Re: [J-core] musl-cross-make / litecross improvements

[Rob Landley]

On 05/02/2016 11:48 PM, Rich Felker wrote:
> I've made a number of improvements and fixes to musl-cross-make which
> are in the upstream repo now, based on bug reports I got:
> 
> - Spurious dependency on flex (upstream's fault, worked around)
> - Spurious dependency on texinfo (ditto)
> - Ability to use pre-installed gmp/mpc/mpfr libs
> - Config examples for static linking, no-debug builds.
> 
> https://github.com/richfelker/musl-cross-make
>
> A few things I still plan to add at some point:

Still no native toolchains. :)

Rob

Re: Re: [J-core] musl-cross-make / litecross improvements

[Szabolcs Nagy]

* Rob Landley <rob@landley.net> [2016-05-04 04:28:18 -0500]:
> On 05/02/2016 11:48 PM, Rich Felker wrote:
> > I've made a number of improvements and fixes to musl-cross-make which
> > are in the upstream repo now, based on bug reports I got:
> > 
> > - Spurious dependency on flex (upstream's fault, worked around)
> > - Spurious dependency on texinfo (ditto)
> > - Ability to use pre-installed gmp/mpc/mpfr libs
> > - Config examples for static linking, no-debug builds.
> > 
> > https://github.com/richfelker/musl-cross-make
> >
> > A few things I still plan to add at some point:
> 
> Still no native toolchains. :)
> 

for native you need a musl based host
at which point you can use a musl based
distro that provides native toolchains.

Re: Re: [J-core] musl-cross-make / litecross improvements

[Laurent Bercot]

On 04/05/2016 13:10, Szabolcs Nagy wrote:
>> Still no native toolchains. :)
>>
>
> for native you need a musl based host
> at which point you can use a musl based
> distro that provides native toolchains.

  Huh? And what if you *are* the musl-based distro and need to build said
native toolchain?
  I'm surprised to hear you, of all people, mentioning "relying on your distro"
as a solution. :P

  I've had success, with the previous iteration of musl-cross-make,
building native toolchains via disabling --host in COMMON_CONFIG
(and compiling gmp, mpfr and mpc for the target first). In other words,
host=target (even if build!=host). They're still considered cross-toolchains,
as in the binaries are prefixed with ${ARCH}- , but they work. I'm not sure
whether it's still possible with the current version of mcm.

-- 
  Laurent

Re: Re: [J-core] musl-cross-make / litecross improvements

[Szabolcs Nagy]

* Laurent Bercot <ska-dietlibc@skarnet.org> [2016-05-04 13:27:22 +0200]:
> On 04/05/2016 13:10, Szabolcs Nagy wrote:
> >>Still no native toolchains. :)
> >>
> >
> >for native you need a musl based host
> >at which point you can use a musl based
> >distro that provides native toolchains.
> 
>  Huh? And what if you *are* the musl-based distro and need to build said
> native toolchain?
>  I'm surprised to hear you, of all people, mentioning "relying on your distro"
> as a solution. :P
> 
>  I've had success, with the previous iteration of musl-cross-make,
> building native toolchains via disabling --host in COMMON_CONFIG
> (and compiling gmp, mpfr and mpc for the target first). In other words,
> host=target (even if build!=host). They're still considered cross-toolchains,
> as in the binaries are prefixed with ${ARCH}- , but they work. I'm not sure
> whether it's still possible with the current version of mcm.

yes, that works, you can cross build a toolchain with host==target
and then it will be a native toolchain.

(i havent tried it with mcm, but first you build a cross toolchain
and then you should be able to use that to build the native one.)

what i meant was that you can only use that toolchain in a native
musl environment and for most users that's a distro with its own
toolchain (otherwise you have to build busybox etc yourself).

Re: Re: [J-core] musl-cross-make / litecross improvements

[Rich Felker]

On Wed, May 04, 2016 at 04:28:18AM -0500, Rob Landley wrote:
> On 05/02/2016 11:48 PM, Rich Felker wrote:
> > I've made a number of improvements and fixes to musl-cross-make which
> > are in the upstream repo now, based on bug reports I got:
> > 
> > - Spurious dependency on flex (upstream's fault, worked around)
> > - Spurious dependency on texinfo (ditto)
> > - Ability to use pre-installed gmp/mpc/mpfr libs
> > - Config examples for static linking, no-debug builds.
> > 
> > https://github.com/richfelker/musl-cross-make
> >
> > A few things I still plan to add at some point:
> 
> Still no native toolchains. :)

In theory all you have to do to get a native toolchain is first build
and install the cross toolchain so that the cross tools are in your
path, then COMMON_CONFIG += --host=$(TARGET). I can test and see if it
works.

Of course it's somewhat large to install on small systems like J2 but
I think you could run it from the sdcard.

Rich

Re: Re: [J-core] musl-cross-make / litecross improvements

[Daniel Cegiełka]

https://github.com/richfelker/musl-cross-make/blob/master/config.mak.dist#L45

whether -static will not be a problem for gcc plugins?

Daniel

Re: Re: [J-core] musl-cross-make / litecross improvements

[Szabolcs Nagy]

* Rich Felker <dalias@libc.org> [2016-05-04 12:33:29 -0400]:
> On Wed, May 04, 2016 at 04:28:18AM -0500, Rob Landley wrote:
> > Still no native toolchains. :)
> 
> In theory all you have to do to get a native toolchain is first build
> and install the cross toolchain so that the cross tools are in your
> path, then COMMON_CONFIG += --host=$(TARGET). I can test and see if it
> works.
> 
> Of course it's somewhat large to install on small systems like J2 but
> I think you could run it from the sdcard.

i tried it for x86_64 and with the following config.mak change

ifeq ($(NATIVE),yes)
COMMON_CONFIG += --host=$(TARGET)
OUTPUT = $(PWD)/output-native
BUILD_DIR = build-$(TARGET)-native
XGCC = $(TARGET)-gcc
PATH_ORIG := $(PATH)
export PATH = $(PWD)/output/bin:$(PATH_ORIG)
endif

make install && make install NATIVE=yes

built a native toolchain into output-native
(it still installs musl into a $(TARGET) subdir, but
i think that's just a matter of copying things around.)

Re: Re: [J-core] musl-cross-make / litecross improvements

[Rich Felker]

On Wed, May 04, 2016 at 12:33:29PM -0400, Rich Felker wrote:
> On Wed, May 04, 2016 at 04:28:18AM -0500, Rob Landley wrote:
> > On 05/02/2016 11:48 PM, Rich Felker wrote:
> > > I've made a number of improvements and fixes to musl-cross-make which
> > > are in the upstream repo now, based on bug reports I got:
> > > 
> > > - Spurious dependency on flex (upstream's fault, worked around)
> > > - Spurious dependency on texinfo (ditto)
> > > - Ability to use pre-installed gmp/mpc/mpfr libs
> > > - Config examples for static linking, no-debug builds.
> > > 
> > > https://github.com/richfelker/musl-cross-make
> > >
> > > A few things I still plan to add at some point:
> > 
> > Still no native toolchains. :)
> 
> In theory all you have to do to get a native toolchain is first build
> and install the cross toolchain so that the cross tools are in your
> path, then COMMON_CONFIG += --host=$(TARGET). I can test and see if it
> works.

Actually it's easier than that -- the whole point of litecross/mcmx is
to automate building musl (which is effectively one of the target
libs, and which the other target libs depend on) in the middle of the
gcc build process so that it can complete in one pass. For
cross-compiling a native compiler for the target system, however, your
existing cross toolchain is what's used to build target libs, and it
already has musl. Actually it already has all the target libs which
you could just reuse rather than building again, so you should be able
to skip building target libs altogether, but I don't think gcc's build
process was made to do that.

Anyway, if you do try to use litecross/mcm for the native compiler, it
breaks on building musl since litecross tries to use the newly-built
xgcc, which is a non-native binary (unless you have qemu + binfmt_misc
installed in such a way that it happens to work). I think it's
reasonably easy to work around this; I just made it work with some
hacks.

Rich

Re: Re: [J-core] musl-cross-make / litecross improvements

[Rich Felker]

On Wed, May 04, 2016 at 07:16:56PM +0200, Szabolcs Nagy wrote:
> * Rich Felker <dalias@libc.org> [2016-05-04 12:33:29 -0400]:
> > On Wed, May 04, 2016 at 04:28:18AM -0500, Rob Landley wrote:
> > > Still no native toolchains. :)
> > 
> > In theory all you have to do to get a native toolchain is first build
> > and install the cross toolchain so that the cross tools are in your
> > path, then COMMON_CONFIG += --host=$(TARGET). I can test and see if it
> > works.
> > 
> > Of course it's somewhat large to install on small systems like J2 but
> > I think you could run it from the sdcard.
> 
> i tried it for x86_64 and with the following config.mak change
> 
> ifeq ($(NATIVE),yes)
> COMMON_CONFIG += --host=$(TARGET)
> OUTPUT = $(PWD)/output-native

In principle I think OUTPUT should be left to the user, but native
compilers are somewhat different since you can't install a bunch of
them in the same location. Not sure what the best way to handle that
is.

> BUILD_DIR = build-$(TARGET)-native
> XGCC = $(TARGET)-gcc

Also the AR and RANLIB passed to musl's make are wrong (they don't run
on the build system). Passing --host to musl's build system (always)
and omitting the AR/RANLIB vars on the make command line (in NATIVE
mode only) is the right solution, I think.

> PATH_ORIG := $(PATH)
> export PATH = $(PWD)/output/bin:$(PATH_ORIG)

This type of approach makes sense for scripting a build in the same
tree, but I don't think we're ready for integrating that sort of
process. It would require rules/dependencies to build the appropriate
cross compiler to begin with and install it to a controlled location
under the build dir. Since native compilers are not really the point
(and easy to do by yourself without litecross; arguably even easier) I
think I'd rather just assume that if the user wants to use litecross
for a native compiler they can either install the necessary cross
compiler in their path or update PATH on their own.

> endif
> 
> make install && make install NATIVE=yes
> 
> built a native toolchain into output-native
> (it still installs musl into a $(TARGET) subdir, but
> i think that's just a matter of copying things around.)

It's easy to change that just by changing the DESTDIR passed to musl's
"make install".

Rich

Re: musl-cross-make / litecross improvements

[Patrick Oppenlander]

[-- Attachment #1: Type: text/plain, Size: 2692 bytes --]

On 03/05/16 14:48, Rich Felker wrote:
> Let me know if any major bugs/inconveniences remain that I should
> prioritize fixing.

Hi Rich,

used this for the first time today (commit 4afd97a). Ran into a build 
failure using this config.mak:

TARGET = arm-linux-musleabi
OUTPUT = /opt/cross
GCC_CONFIG += --with-cpu=cortex-a8

I can send a full build log to your personal mail (~600KiB) if it helps.

libtool: compile: 
/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./gcc/xgcc 
-B/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./gcc/ 
-B/arm-linux-musleabi/bin/ -B/arm-linux-musleabi/lib/ -isystem 
/arm-linux-musleabi/include -isystem /arm-linux-musleabi/sys-include 
-L/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./ld 
--sysroot=/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_sysroot 
-DHAVE_CONFIG_H -I. -I../../../src_toolchain/boehm-gc -I./include 
-I/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/src_toolchain/boehm-gc/include 
-fexceptions -Iinclude -I././targ-include -I.//libc/include -g -O2 -MT 
os_dep.lo -MD -MP -MF .deps/os_dep.Tpo -c 
../../../src_toolchain/boehm-gc/os_dep.c  -fPIC -DPIC -o .libs/os_dep.o
../../../src_toolchain/boehm-gc/os_dep.c:20:30: fatal error: 
linux/version.h: No such file or directory
compilation terminated.
Makefile:444: recipe for target 'os_dep.lo' failed
make[5]: *** [os_dep.lo] Error 1
make[5]: Leaving directory 
'/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/arm-linux-musleabi/boehm-gc'
Makefile:490: recipe for target 'all-recursive' failed
make[4]: *** [all-recursive] Error 1
make[4]: Leaving directory 
'/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/arm-linux-musleabi/boehm-gc'
Makefile:18152: recipe for target 'all-target-boehm-gc' failed
make[3]: *** [all-target-boehm-gc] Error 2
make[3]: Leaving directory 
'/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain'
Makefile:878: recipe for target 'all' failed
make[2]: *** [all] Error 2
make[2]: Leaving directory 
'/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain'
Makefile:132: recipe for target 'obj_toolchain/.lc_built' failed
make[1]: *** [obj_toolchain/.lc_built] Error 2
make[1]: Leaving directory 
'/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi'
Makefile:133: recipe for target 'all' failed
make: *** [all] Error 2
make  1325.21s user 101.15s system 91% cpu 26:03.63 total


Are you planning on supporting GCC 5.3? I may be able to contribute some 
patches.

         Patrick

[-- Attachment #2: Type: text/html, Size: 3703 bytes --]

Re: musl-cross-make / litecross improvements

[Rich Felker]

On Fri, May 06, 2016 at 08:43:58AM +1000, Patrick Oppenlander wrote:
> On 03/05/16 14:48, Rich Felker wrote:
> >Let me know if any major bugs/inconveniences remain that I should
> >prioritize fixing.
> 
> Hi Rich,
> 
> used this for the first time today (commit 4afd97a). Ran into a
> build failure using this config.mak:
> 
> TARGET = arm-linux-musleabi
> OUTPUT = /opt/cross
> GCC_CONFIG += --with-cpu=cortex-a8
> 
> I can send a full build log to your personal mail (~600KiB) if it helps.
> 
> libtool: compile: /home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./gcc/xgcc -B/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./gcc/
> -B/arm-linux-musleabi/bin/ -B/arm-linux-musleabi/lib/ -isystem
> /arm-linux-musleabi/include -isystem /arm-linux-musleabi/sys-include -L/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_toolchain/./ld --sysroot=/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/obj_sysroot
> -DHAVE_CONFIG_H -I. -I../../../src_toolchain/boehm-gc -I./include -I/home/patrick/src/patrick/musl-cross-make/build-arm-linux-musleabi/src_toolchain/boehm-gc/include
> -fexceptions -Iinclude -I././targ-include -I.//libc/include -g -O2
> -MT os_dep.lo -MD -MP -MF .deps/os_dep.Tpo -c
> .../../../src_toolchain/boehm-gc/os_dep.c  -fPIC -DPIC -o
> .libs/os_dep.o
> .../../../src_toolchain/boehm-gc/os_dep.c:20:30: fatal error:
> linux/version.h: No such file or directory
> compilation terminated.

It looks like there's a useless dependency on kernel headers in stuff
for the target libs. I suspect you might have omitted the recommended
--enable-languages=c,c++ and let it build all langs; IIRC boehm-gc is
not built at all for a c/c++ only build. Other langs are completely
untested and probably don't work, but it would be nice to find out why
and fix the ones that are practical to fix.

I should probably also add COMMON_CONFIG += --enable-languages=c,c++
_before_ config.mak inclusion so that, by default, you get the working
configuration. Having this before config.mak should make it so any
--enable-languages option you manually add with += takes precedence.

> Are you planning on supporting GCC 5.3? I may be able to contribute
> some patches.

I suspect the same patches for 5.2 apply just fine, but I haven't
taken the time to test yet. If you can confirm they work or tweak them
so they work I'd be happy to add 5.3 support. Other versions I'd like
to support are 4.7.4 (last C-only, also last before some sketchy
optimizations were added) and 6.1.0, but in order to add a version it
should have proper support (at least the main musl patch with dynamic
linker names, include paths, etc. fully ported) rather than just being
enough to compile.

Rich

Re: musl-cross-make / litecross improvements

[Rich Felker]

On Tue, May 03, 2016 at 11:57:05PM +0200, Szabolcs Nagy wrote:
> * Szabolcs Nagy <nsz@port70.net> [2016-05-03 22:16:22 +0200]:
> > * Rich Felker <dalias@libc.org> [2016-05-03 14:02:30 -0400]:
> > > On Tue, May 03, 2016 at 01:39:43PM +0200, Szabolcs Nagy wrote:
> > > > i think the usr/ and lib64/ symlinks are useful
> > > > (so it can be used as rootfs without fiddling
> > > > with etc/ld-musl*.path).
> > > 
> > > Yes. Is there a good way to override that in gcc or should we just
> > > make the symlinks?
> > > 
> > 
> > output/lib64 can be eliminated by
> > COMMON_CONFIG += --libdir=/lib
> > 
> > output/x86_64-linux-musl/lib64 install path is trickier:
> > it is controlled by the $toolexeclibdir make variable.
> > which is set according to $CC -print-multi-os-directory
> > which is controlled by multilib and multilib_defaults from
> > $CC -dumpspecs which comes from multilib.h generated by
> > genmultilib based on parameters from config/i386/t-linux64
> > 
> 
> it was not clear if the t-linux64 thing could be overridden, but
> 
> GCC_CONFIG += --with-multilib-list=
> 
> fixes it (the lib dir is lib/ then).

I've looked into this more, and while I think your approach works in
practice, I'm a bit concerned that --with-multilib-list= is processed
per-target and in theory the blank list might break something. I tried
x86_64, sh, and aarch64, but several other archs remain, I think.

The root cause of this bug seems to be a broken conditional in
gcc/Makefile.in; for the s-mlib rule, the condition for building
multilib layout is:

	if test @enable_multilib@ = yes \
	   || test -n "$(MULTILIB_OSDIRNAMES)"; then \

I believe the || should have been &&.

In any case, forcing MULTILIB_OSDIRNAMES= on the make command line
seems like a viable solution. I'm testing it now and I'll probably
commit as long as it works.

Rich

Re: musl-cross-make / litecross improvements

[Patrick Oppenlander]

[-- Attachment #1: Type: text/plain, Size: 1873 bytes --]

On 06/05/16 12:44, Rich Felker wrote:
> It looks like there's a useless dependency on kernel headers in stuff
> for the target libs. I suspect you might have omitted the recommended
> --enable-languages=c,c++ and let it build all langs; IIRC boehm-gc is
> not built at all for a c/c++ only build. Other langs are completely
> untested and probably don't work, but it would be nice to find out why
> and fix the ones that are practical to fix.
>
> I should probably also add COMMON_CONFIG += --enable-languages=c,c++
> _before_ config.mak inclusion so that, by default, you get the working
> configuration. Having this before config.mak should make it so any
> --enable-languages option you manually add with += takes precedence.

I think that's a good idea.

README.md says that the only mandatory variable is TARGET. I assumed 
c,c++ only was default.

>
>> Are you planning on supporting GCC 5.3? I may be able to contribute
>> some patches.
> I suspect the same patches for 5.2 apply just fine, but I haven't
> taken the time to test yet. If you can confirm they work or tweak them
> so they work I'd be happy to add 5.3 support. Other versions I'd like
> to support are 4.7.4 (last C-only, also last before some sketchy
> optimizations were added) and 6.1.0, but in order to add a version it
> should have proper support (at least the main musl patch with dynamic
> linker names, include paths, etc. fully ported) rather than just being
> enough to compile.

I had a quick look. Patches apply with two very minor adjustments, I've 
attached the edited patches. I rebuilt arm-linux-musleabi but haven't 
used it in anger yet. Is there a way to easily check all targets?

Also, is there a way to get linux headers installed with the toolchain 
(like crosstool does)?

I use 4.9.3 for building old arm 2.6 kernels and haven't had a problem 
with it yet.

         Patrick

[-- Attachment #2: 0008-shsibcall.diff --]
[-- Type: text/x-patch, Size: 1288 bytes --]

--- a/gcc/config/sh/sh.md (revision 233324)
+++ b/gcc/config/sh/sh.md (working copy)
@@ -10476,7 +10476,7 @@
        (call (mem:SI (match_operand:SI 1 "symbol_ref_operand" ""))
              (match_operand 2 "" "")))
    (use (reg:SI FPSCR_MODES_REG))
-   (clobber (match_scratch:SI 3 "=&k"))
+   (clobber (reg:SI R1_REG))
    (return)]
   "TARGET_SH2 && !TARGET_FDPIC"
   "#"
@@ -10491,6 +10495,8 @@
   rtx lab = PATTERN (gen_call_site ());
   rtx call_insn;

+  operands[3] =  gen_rtx_REG (SImode, R1_REG);
+
   sh_expand_sym_label2reg (operands[3], operands[1], lab, true);
   call_insn = emit_call_insn (gen_sibcall_valuei_pcrel (operands[0],
                                                        operands[3],
@@ -10511,7 +10519,7 @@
              (match_operand 2)))
    (use (reg:SI FPSCR_MODES_REG))
    (use (reg:SI PIC_REG))
-   (clobber (match_scratch:SI 3 "=k"))
+   (clobber (reg:SI R1_REG))
    (return)]
   "TARGET_SH2 && TARGET_FDPIC"
   "#"
@@ -10520,6 +10528,8 @@
 {
   rtx lab = PATTERN (gen_call_site ());

+  operands[3] =  gen_rtx_REG (SImode, R1_REG);
+
   sh_expand_sym_label2reg (operands[3], operands[1], lab, true);
   rtx i = emit_call_insn (gen_sibcall_valuei_pcrel_fdpic (operands[0],
                                                          operands[3],


[-- Attachment #3: 0001-musl.diff --]
[-- Type: text/x-patch, Size: 33691 bytes --]

diff --git a/fixincludes/mkfixinc.sh b/fixincludes/mkfixinc.sh
index 6653fed..0d96c8c 100755
--- a/fixincludes/mkfixinc.sh
+++ b/fixincludes/mkfixinc.sh
@@ -19,7 +19,8 @@ case $machine in
     powerpc-*-eabi*    | \
     powerpc-*-rtems*   | \
     powerpcle-*-eabisim* | \
-    powerpcle-*-eabi* )
+    powerpcle-*-eabi* | \
+    *-musl* )
 	#  IF there is no include fixing,
 	#  THEN create a no-op fixer and exit
 	(echo "#! /bin/sh" ; echo "exit 0" ) > ${target}
diff --git a/gcc/config.gcc b/gcc/config.gcc
index 3ede69b..d9eb8cf 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -575,7 +575,7 @@ case ${target} in
 esac
 
 # Common C libraries.
-tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3"
+tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3 LIBC_MUSL=4"
 
 # 32-bit x86 processors supported by --with-arch=.  Each processor
 # MUST be separated by exactly one space.
@@ -720,6 +720,9 @@ case ${target} in
     *-*-*uclibc*)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
       ;;
+    *-*-*musl*)
+      tm_defines="$tm_defines DEFAULT_LIBC=LIBC_MUSL"
+      ;;
     *)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"
       ;;
diff --git a/gcc/config/aarch64/aarch64-linux.h b/gcc/config/aarch64/aarch64-linux.h
index ba7fc3b..1600a32 100644
--- a/gcc/config/aarch64/aarch64-linux.h
+++ b/gcc/config/aarch64/aarch64-linux.h
@@ -23,6 +23,9 @@
 
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"
 
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"
+
 #undef  ASAN_CC1_SPEC
 #define ASAN_CC1_SPEC "%{%:sanitize(address):-funwind-tables}"
 
diff --git a/gcc/config/alpha/linux.h b/gcc/config/alpha/linux.h
index c567f43..475ea06 100644
--- a/gcc/config/alpha/linux.h
+++ b/gcc/config/alpha/linux.h
@@ -61,10 +61,14 @@ along with GCC; see the file COPYING3.  If not see
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* Determine what functions are present at the runtime;
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index e9d65dc..f12e6bd 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -77,6 +77,23 @@
     %{mfloat-abi=soft*:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "} \
     %{!mfloat-abi=*:" GLIBC_DYNAMIC_LINKER_DEFAULT "}"
 
+/* For ARM musl currently supports four dynamic linkers:
+   - ld-musl-arm.so.1 - for the EABI-derived soft-float ABI
+   - ld-musl-armhf.so.1 - for the EABI-derived hard-float ABI
+   - ld-musl-armeb.so.1 - for the EABI-derived soft-float ABI, EB
+   - ld-musl-armebhf.so.1 - for the EABI-derived hard-float ABI, EB
+   musl does not support the legacy OABI mode.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, EL. */
+#undef  MUSL_DYNAMIC_LINKER
+#if TARGET_BIG_ENDIAN_DEFAULT
+#define MUSL_DYNAMIC_LINKER_E "%{mlittle-endian:;:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
+#endif
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
+
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */
 #undef  LINK_SPEC
diff --git a/gcc/config/glibc-stdint.h b/gcc/config/glibc-stdint.h
index 3fc67dc..98f4f04 100644
--- a/gcc/config/glibc-stdint.h
+++ b/gcc/config/glibc-stdint.h
@@ -22,6 +22,12 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+/* Systems using musl libc should use this header and make sure
+   OPTION_MUSL is defined correctly before using the TYPE macros. */
+#ifndef OPTION_MUSL
+#define OPTION_MUSL 0
+#endif
+
 #define SIG_ATOMIC_TYPE "int"
 
 #define INT8_TYPE "signed char"
@@ -43,12 +49,12 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define UINT_LEAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "long long unsigned int")
 
 #define INT_FAST8_TYPE "signed char"
-#define INT_FAST16_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
-#define INT_FAST32_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
+#define INT_FAST16_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long int" : "int")
+#define INT_FAST32_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long int" : "int")
 #define INT_FAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "long long int")
 #define UINT_FAST8_TYPE "unsigned char"
-#define UINT_FAST16_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "unsigned int")
-#define UINT_FAST32_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "unsigned int")
+#define UINT_FAST16_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long unsigned int" : "unsigned int")
+#define UINT_FAST32_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long unsigned int" : "unsigned int")
 #define UINT_FAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "long long unsigned int")
 
 #define INTPTR_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
diff --git a/gcc/config/i386/linux.h b/gcc/config/i386/linux.h
index a100963..385aefd 100644
--- a/gcc/config/i386/linux.h
+++ b/gcc/config/i386/linux.h
@@ -21,3 +21,6 @@ along with GCC; see the file COPYING3.  If not see
 
 #define GNU_USER_LINK_EMULATION "elf_i386"
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-i386.so.1"
diff --git a/gcc/config/i386/linux64.h b/gcc/config/i386/linux64.h
index a27d3be..e300480 100644
--- a/gcc/config/i386/linux64.h
+++ b/gcc/config/i386/linux64.h
@@ -30,3 +30,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define GLIBC_DYNAMIC_LINKER32 "/lib/ld-linux.so.2"
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld-linux-x86-64.so.2"
 #define GLIBC_DYNAMIC_LINKERX32 "/libx32/ld-linux-x32.so.2"
+
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-i386.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-x86_64.so.1"
+#undef MUSL_DYNAMIC_LINKERX32
+#define MUSL_DYNAMIC_LINKERX32 "/lib/ld-musl-x32.so.1"
diff --git a/gcc/config/linux.h b/gcc/config/linux.h
index 857389a..7bc87ab 100644
--- a/gcc/config/linux.h
+++ b/gcc/config/linux.h
@@ -32,10 +32,14 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 #define GNU_USER_TARGET_OS_CPP_BUILTINS()			\
@@ -50,21 +54,25 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     } while (0)
 
 /* Determine which dynamic linker to use depending on whether GLIBC or
-   uClibc or Bionic is the default C library and whether
-   -muclibc or -mglibc or -mbionic has been passed to change the default.  */
+   uClibc or Bionic or musl is the default C library and whether
+   -muclibc or -mglibc or -mbionic or -mmusl has been passed to change
+   the default.  */
 
-#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LD1, LD2, LD3)	\
-  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:" LD1 "}}"
+#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LIBC4, LD1, LD2, LD3, LD4)	\
+  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:%{" LIBC4 ":" LD4 ";:" LD1 "}}}"
 
 #if DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", G, U, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", "mmusl", G, U, B, M)
 #elif DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", U, G, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", "mmusl", U, G, B, M)
 #elif DEFAULT_LIBC == LIBC_BIONIC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", B, G, U)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", "mmusl", B, G, U, M)
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mmusl", "mglibc", "muclibc", "mbionic", M, G, U, B)
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif /* DEFAULT_LIBC */
@@ -81,24 +89,100 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define BIONIC_DYNAMIC_LINKER32 "/system/bin/linker"
 #define BIONIC_DYNAMIC_LINKER64 "/system/bin/linker64"
 #define BIONIC_DYNAMIC_LINKERX32 "/system/bin/linkerx32"
+/* Should be redefined for each target that supports musl.  */
+#define MUSL_DYNAMIC_LINKER "/dev/null"
+#define MUSL_DYNAMIC_LINKER32 "/dev/null"
+#define MUSL_DYNAMIC_LINKER64 "/dev/null"
+#define MUSL_DYNAMIC_LINKERX32 "/dev/null"
 
 #define GNU_USER_DYNAMIC_LINKER						\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER,	\
-			 BIONIC_DYNAMIC_LINKER)
+			 BIONIC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
 #define GNU_USER_DYNAMIC_LINKER32					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, \
-			 BIONIC_DYNAMIC_LINKER32)
+			 BIONIC_DYNAMIC_LINKER32, MUSL_DYNAMIC_LINKER32)
 #define GNU_USER_DYNAMIC_LINKER64					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, \
-			 BIONIC_DYNAMIC_LINKER64)
+			 BIONIC_DYNAMIC_LINKER64, MUSL_DYNAMIC_LINKER64)
 #define GNU_USER_DYNAMIC_LINKERX32					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERX32, UCLIBC_DYNAMIC_LINKERX32, \
-			 BIONIC_DYNAMIC_LINKERX32)
+			 BIONIC_DYNAMIC_LINKERX32, MUSL_DYNAMIC_LINKERX32)
 
 /* Whether we have Bionic libc runtime */
 #undef TARGET_HAS_BIONIC
 #define TARGET_HAS_BIONIC (OPTION_BIONIC)
 
+/* musl avoids problematic includes by rearranging the include directories.
+ * Unfortunately, this is mostly duplicated from cppdefault.c */
+#if DEFAULT_LIBC == LIBC_MUSL
+#define INCLUDE_DEFAULTS_MUSL_GPP			\
+    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },		\
+    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 1 },		\
+    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1,	\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },
+
+#ifdef LOCAL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_LOCAL			\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },		\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_LOCAL
+#endif
+
+#ifdef PREFIX_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_PREFIX
+#endif
+
+#ifdef CROSS_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_CROSS			\
+    { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#ifdef TOOL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_TOOL			\
+    { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_TOOL
+#endif
+
+#ifdef NATIVE_SYSTEM_HEADER_DIR
+#define INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 },	\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_NATIVE
+#endif
+
+#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
+# undef INCLUDE_DEFAULTS_MUSL_LOCAL
+# define INCLUDE_DEFAULTS_MUSL_LOCAL
+# undef INCLUDE_DEFAULTS_MUSL_NATIVE
+# define INCLUDE_DEFAULTS_MUSL_NATIVE
+#else
+# undef INCLUDE_DEFAULTS_MUSL_CROSS
+# define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#undef INCLUDE_DEFAULTS
+#define INCLUDE_DEFAULTS				\
+  {							\
+    INCLUDE_DEFAULTS_MUSL_GPP				\
+    INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    INCLUDE_DEFAULTS_MUSL_CROSS				\
+    INCLUDE_DEFAULTS_MUSL_TOOL				\
+    INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 },		\
+    { 0, 0, 0, 0, 0, 0 }				\
+  }
+#endif
+
 #if (DEFAULT_LIBC == LIBC_UCLIBC) && defined (SINGLE_LIBC) /* uClinux */
 /* This is a *uclinux* target.  We don't define below macros to normal linux
    versions, because doing so would require *uclinux* targets to include
diff --git a/gcc/config/linux.opt b/gcc/config/linux.opt
index c054338..ef055a7 100644
--- a/gcc/config/linux.opt
+++ b/gcc/config/linux.opt
@@ -28,5 +28,9 @@ Target Report RejectNegative Var(linux_libc,LIBC_GLIBC) Negative(muclibc)
 Use GNU C library
 
 muclibc
-Target Report RejectNegative Var(linux_libc,LIBC_UCLIBC) Negative(mbionic)
+Target Report RejectNegative Var(linux_libc,LIBC_UCLIBC) Negative(mmusl)
 Use uClibc C library
+
+mmusl
+Target Report RejectNegative Var(linux_libc,LIBC_MUSL) Negative(mbionic)
+Use musl C library
diff --git a/gcc/config/microblaze/linux.h b/gcc/config/microblaze/linux.h
index 655a70f..a8a3f3e 100644
--- a/gcc/config/microblaze/linux.h
+++ b/gcc/config/microblaze/linux.h
@@ -28,10 +28,20 @@
 #undef TLS_NEEDS_GOT
 #define TLS_NEEDS_GOT 1
 
-#define DYNAMIC_LINKER "/lib/ld.so.1"
+#define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
+
+#if TARGET_BIG_ENDIAN_DEFAULT == 0 /* LE */
+#define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:;:el}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{mlittle-endian:el}"
+#endif
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-microblaze" MUSL_DYNAMIC_LINKER_E ".so.1"
+
 #undef  SUBTARGET_EXTRA_SPECS
 #define SUBTARGET_EXTRA_SPECS \
-  { "dynamic_linker", DYNAMIC_LINKER }
+  { "dynamic_linker", GNU_USER_DYNAMIC_LINKER }
 
 #undef LINK_SPEC
 #define LINK_SPEC "%{shared:-shared} \
diff --git a/gcc/config/mips/linux.h b/gcc/config/mips/linux.h
index 91df261..fb358e2 100644
--- a/gcc/config/mips/linux.h
+++ b/gcc/config/mips/linux.h
@@ -37,7 +37,13 @@ along with GCC; see the file COPYING3.  If not see
 #define UCLIBC_DYNAMIC_LINKERN32 \
   "%{mnan=2008:/lib32/ld-uClibc-mipsn8.so.0;:/lib32/ld-uClibc.so.0}"
 
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-mips%{EL:el}%{msoft-float:-sf}.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-mips64%{EL:el}%{msoft-float:-sf}.so.1"
+#define MUSL_DYNAMIC_LINKERN32 "/lib/ld-musl-mipsn32%{EL:el}%{msoft-float:-sf}.so.1"
+
 #define BIONIC_DYNAMIC_LINKERN32 "/system/bin/linker32"
 #define GNU_USER_DYNAMIC_LINKERN32 \
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERN32, UCLIBC_DYNAMIC_LINKERN32, \
-                         BIONIC_DYNAMIC_LINKERN32)
+                         BIONIC_DYNAMIC_LINKERN32, MUSL_DYNAMIC_LINKERN32)
diff --git a/gcc/config/rs6000/linux.h b/gcc/config/rs6000/linux.h
index fe0ebd6..a68ff69 100644
--- a/gcc/config/rs6000/linux.h
+++ b/gcc/config/rs6000/linux.h
@@ -30,10 +30,14 @@
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* Determine what functions are present at the runtime;
diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index 0879e7e..6a7d435 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -299,10 +299,14 @@ extern int dot_symbols;
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* Determine what functions are present at the runtime;
@@ -365,17 +369,23 @@ extern int dot_symbols;
 #endif
 #define UCLIBC_DYNAMIC_LINKER32 "/lib/ld-uClibc.so.0"
 #define UCLIBC_DYNAMIC_LINKER64 "/lib/ld64-uClibc.so.0"
+#define MUSL_DYNAMIC_LINKER32 \
+  "/lib/ld-musl-powerpc" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
+#define MUSL_DYNAMIC_LINKER64 \
+  "/lib/ld-musl-powerpc64" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
 #if DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";:%{mmusl:" M ";:" U "}}"
 #elif DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{muclibc:" U ";:%{mmusl:" M ";:" G "}}"
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";:%{muclibc:" U ";:" M "}}"
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif
 #define GNU_USER_DYNAMIC_LINKER32 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, MUSL_DYNAMIC_LINKER32)
 #define GNU_USER_DYNAMIC_LINKER64 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, MUSL_DYNAMIC_LINKER64)
 
 #undef  DEFAULT_ASM_ENDIAN
 #if (TARGET_DEFAULT & MASK_LITTLE_ENDIAN)
diff --git a/gcc/config/rs6000/secureplt.h b/gcc/config/rs6000/secureplt.h
index b463463..77edf2a 100644
--- a/gcc/config/rs6000/secureplt.h
+++ b/gcc/config/rs6000/secureplt.h
@@ -18,3 +18,4 @@ along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
 #define CC1_SECURE_PLT_DEFAULT_SPEC "-msecure-plt"
+#define LINK_SECURE_PLT_DEFAULT_SPEC "--secure-plt"
diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
index 9917c2f..68365de 100644
--- a/gcc/config/rs6000/sysv4.h
+++ b/gcc/config/rs6000/sysv4.h
@@ -537,6 +537,9 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
 #ifndef CC1_SECURE_PLT_DEFAULT_SPEC
 #define CC1_SECURE_PLT_DEFAULT_SPEC ""
 #endif
+#ifndef LINK_SECURE_PLT_DEFAULT_SPEC
+#define LINK_SECURE_PLT_DEFAULT_SPEC ""
+#endif
 
 /* Pass -G xxx to the compiler.  */
 #undef CC1_SPEC
@@ -574,7 +577,8 @@
 %{R*} \
 %(link_shlib) \
 %{!T*: %(link_start) } \
-%(link_os)"
+%(link_os)" \
+"%{!mbss-plt: %{!msecure-plt: %(link_secure_plt_default)}}"
 
 /* Shared libraries are not default.  */
 #define LINK_SHLIB_SPEC "\
@@ -762,17 +766,23 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
 
 #define LINK_START_LINUX_SPEC ""
 
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","")
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
 #define UCLIBC_DYNAMIC_LINKER "/lib/ld-uClibc.so.0"
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-powerpc" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
 #if DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";:%{mmusl:" M ";:" U "}}"
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";:%{muclibc:" U ";:" M "}}"
 #elif !defined (DEFAULT_LIBC) || DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{muclibc:" U ";:%{mmusl:" M ";:" G "}}"
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif
 #define GNU_USER_DYNAMIC_LINKER \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
 
 #define LINK_OS_LINUX_SPEC "-m elf32ppclinux %{!shared: %{!static: \
   %{rdynamic:-export-dynamic} \
@@ -895,6 +905,7 @@ ncrtn.o%s"
   { "link_os_openbsd",		LINK_OS_OPENBSD_SPEC },			\
   { "link_os_default",		LINK_OS_DEFAULT_SPEC },			\
   { "cc1_secure_plt_default",	CC1_SECURE_PLT_DEFAULT_SPEC },		\
+  { "link_secure_plt_default",	LINK_SECURE_PLT_DEFAULT_SPEC },		\
   { "cpp_os_ads",		CPP_OS_ADS_SPEC },			\
   { "cpp_os_yellowknife",	CPP_OS_YELLOWKNIFE_SPEC },		\
   { "cpp_os_mvme",		CPP_OS_MVME_SPEC },			\
@@ -949,3 +960,72 @@ ncrtn.o%s"
 /* This target uses the sysv4.opt file.  */
 #define TARGET_USES_SYSV4_OPT 1
 
+/* Include order changes for musl, same as in generic linux.h.  */
+#if DEFAULT_LIBC == LIBC_MUSL
+#define INCLUDE_DEFAULTS_MUSL_GPP			\
+    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },		\
+    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 1 },		\
+    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1,	\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },
+
+#ifdef LOCAL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_LOCAL			\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },		\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_LOCAL
+#endif
+
+#ifdef PREFIX_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_PREFIX
+#endif
+
+#ifdef CROSS_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_CROSS			\
+    { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#ifdef TOOL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_TOOL			\
+    { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_TOOL
+#endif
+
+#ifdef NATIVE_SYSTEM_HEADER_DIR
+#define INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 },	\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_NATIVE
+#endif
+
+#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
+# undef INCLUDE_DEFAULTS_MUSL_LOCAL
+# define INCLUDE_DEFAULTS_MUSL_LOCAL
+# undef INCLUDE_DEFAULTS_MUSL_NATIVE
+# define INCLUDE_DEFAULTS_MUSL_NATIVE
+#else
+# undef INCLUDE_DEFAULTS_MUSL_CROSS
+# define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#undef INCLUDE_DEFAULTS
+#define INCLUDE_DEFAULTS				\
+  {							\
+    INCLUDE_DEFAULTS_MUSL_GPP				\
+    INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    INCLUDE_DEFAULTS_MUSL_CROSS				\
+    INCLUDE_DEFAULTS_MUSL_TOOL				\
+    INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 },		\
+    { 0, 0, 0, 0, 0, 0 }				\
+  }
+#endif
diff --git a/gcc/config/rs6000/sysv4le.h b/gcc/config/rs6000/sysv4le.h
index 7b1d6a1..064323c 100644
--- a/gcc/config/rs6000/sysv4le.h
+++ b/gcc/config/rs6000/sysv4le.h
@@ -35,3 +35,5 @@
 /* Little-endian PowerPC64 Linux uses the ELF v2 ABI by default.  */
 #define LINUX64_DEFAULT_ABI_ELFv2
 
+#undef MUSL_DYNAMIC_LINKER_E
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","le")
diff --git a/gcc/config/sh/linux.h b/gcc/config/sh/linux.h
index 0f5d614..4c167c6 100644
--- a/gcc/config/sh/linux.h
+++ b/gcc/config/sh/linux.h
@@ -43,6 +43,29 @@ along with GCC; see the file COPYING3.  If not see
 
 #define TARGET_ASM_FILE_END file_end_indicate_exec_stack
 
+#if TARGET_ENDIAN_DEFAULT == MASK_LITTLE_ENDIAN
+#define MUSL_DYNAMIC_LINKER_E "%{mb:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{!ml:eb}"
+#endif
+
+#if TARGET_CPU_DEFAULT & ( MASK_HARD_SH2A_DOUBLE | MASK_SH4 )
+/* "-nofpu" if any nofpu option is specified */
+#define MUSL_DYNAMIC_LINKER_FP \
+  "%{m1|m2|m2a-nofpu|m3|m4-nofpu|m4-100-nofpu|m4-200-nofpu|m4-300-nofpu|" \
+  "m4-340|m4-400|m4-500|m4al|m5-32media-nofpu|m5-64media-nofpu|" \
+  "m5-compact-nofpu:-nofpu}"
+#else
+/* "-nofpu" if none of the hard fpu options are specified */
+#define MUSL_DYNAMIC_LINKER_FP \
+  "%{m2a|m4|m4-100|m4-200|m4-300|m4a|m5-32media|m5-64media|m5-compact:;:-nofpu}"
+#endif
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-sh" MUSL_DYNAMIC_LINKER_E MUSL_DYNAMIC_LINKER_FP \
+  "%{mfdpic:-fdpic}.so.1"
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
 
 #undef SUBTARGET_LINK_EMUL_SUFFIX
diff --git a/gcc/configure b/gcc/configure
index 0037240..66aab9f 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -27742,6 +27742,9 @@ if test "${gcc_cv_libc_provides_ssp+set}" = set; then :
 else
   gcc_cv_libc_provides_ssp=no
     case "$target" in
+       *-*-musl*)
+	 # All versions of musl provide stack protector
+	 gcc_cv_libc_provides_ssp=yes;;
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)
       # glibc 2.4 and later provides __stack_chk_fail and
       # either __stack_chk_guard, or TLS access to stack guard canary.
@@ -27774,6 +27777,7 @@ fi
 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now
 	 # simply assert that glibc does provide this, which is true for all
 	 # realistically usable GNU/Hurd configurations.
+	 # All supported versions of musl provide it as well
 	 gcc_cv_libc_provides_ssp=yes;;
        *-*-darwin* | *-*-freebsd*)
 	 ac_fn_c_check_func "$LINENO" "__stack_chk_fail" "ac_cv_func___stack_chk_fail"
@@ -27870,6 +27874,9 @@ case "$target" in
       gcc_cv_target_dl_iterate_phdr=no
     fi
     ;;
+  *-linux-musl*)
+    gcc_cv_target_dl_iterate_phdr=yes
+    ;;
 esac
 
 if test x$gcc_cv_target_dl_iterate_phdr = xyes; then
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 6f38ba1..b81960c 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5229,6 +5229,9 @@ AC_CACHE_CHECK(__stack_chk_fail in target C library,
       gcc_cv_libc_provides_ssp,
       [gcc_cv_libc_provides_ssp=no
     case "$target" in
+       *-*-musl*)
+	 # All versions of musl provide stack protector
+	 gcc_cv_libc_provides_ssp=yes;;
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)
       # glibc 2.4 and later provides __stack_chk_fail and
       # either __stack_chk_guard, or TLS access to stack guard canary.
@@ -5255,6 +5258,7 @@ AC_CACHE_CHECK(__stack_chk_fail in target C library,
 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now
 	 # simply assert that glibc does provide this, which is true for all
 	 # realistically usable GNU/Hurd configurations.
+	 # All supported versions of musl provide it as well
 	 gcc_cv_libc_provides_ssp=yes;;
        *-*-darwin* | *-*-freebsd*)
 	 AC_CHECK_FUNC(__stack_chk_fail,[gcc_cv_libc_provides_ssp=yes],
@@ -5328,6 +5332,9 @@ case "$target" in
       gcc_cv_target_dl_iterate_phdr=no
     fi
     ;;
+  *-linux-musl*)
+    gcc_cv_target_dl_iterate_phdr=yes
+    ;;
 esac
 GCC_TARGET_TEMPLATE([TARGET_DL_ITERATE_PHDR])
 if test x$gcc_cv_target_dl_iterate_phdr = xyes; then
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index f84a199..ee9765b 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -667,7 +667,7 @@ Objective-C and Objective-C++ Dialects}.
 -mcpu=@var{cpu}}
 
 @emph{GNU/Linux Options}
-@gccoptlist{-mglibc -muclibc -mbionic -mandroid @gol
+@gccoptlist{-mglibc -muclibc -mmusl -mbionic -mandroid @gol
 -tno-android-cc -tno-android-ld}
 
 @emph{H8/300 Options}
@@ -15324,13 +15324,19 @@ These @samp{-m} options are defined for GNU/Linux targets:
 @item -mglibc
 @opindex mglibc
 Use the GNU C library.  This is the default except
-on @samp{*-*-linux-*uclibc*} and @samp{*-*-linux-*android*} targets.
+on @samp{*-*-linux-*uclibc*}, @samp{*-*-linux-*musl*} and
+@samp{*-*-linux-*android*} targets.
 
 @item -muclibc
 @opindex muclibc
 Use uClibc C library.  This is the default on
 @samp{*-*-linux-*uclibc*} targets.
 
+@item -mmusl
+@opindex mmusl
+Use the musl C library.  This is the default on
+@samp{*-*-linux-*musl*} targets.
+
 @item -mbionic
 @opindex mbionic
 Use Bionic C library.  This is the default on
diff --git a/libcilkrts/runtime/os-unix.c b/libcilkrts/runtime/os-unix.c
index cb582dd..e43d7d5 100644
--- a/libcilkrts/runtime/os-unix.c
+++ b/libcilkrts/runtime/os-unix.c
@@ -51,6 +51,7 @@
 #if defined __linux__
 #   include <sys/sysinfo.h>
 #   include <sys/syscall.h>
+#   include <sched.h>
 #elif defined __APPLE__
 #   include <sys/sysctl.h>
     // Uses sysconf(_SC_NPROCESSORS_ONLN) in verbose output
@@ -400,28 +401,19 @@ COMMON_SYSDEP void __cilkrts_sleep(void)
 
 COMMON_SYSDEP void __cilkrts_yield(void)
 {
-#if __APPLE__ || __FreeBSD__ || __VXWORKS__
-    // On MacOS, call sched_yield to yield quantum.  I'm not sure why we
-    // don't do this on Linux also.
-    sched_yield();
-#elif defined(__DragonFly__)
-    // On DragonFly BSD, call sched_yield to yield quantum.
-    sched_yield();
-#elif defined(__MIC__)
+#if defined(__MIC__)
     // On MIC, pthread_yield() really trashes things.  Arch's measurements
     // showed that calling _mm_delay_32() (or doing nothing) was a better
     // option.  Delaying 1024 clock cycles is a reasonable compromise between
     // giving up the processor and latency starting up when work becomes
     // available
     _mm_delay_32(1024);
-#elif defined(__ANDROID__) || (defined(__sun__) && defined(__svr4__))
-    // On Android and Solaris, call sched_yield to yield quantum.  I'm not
-    // sure why we don't do this on Linux also.
-    sched_yield();
-#else
-    // On Linux, call pthread_yield (which in turn will call sched_yield)
-    // to yield quantum.
+#elif defined(__sun__) && !defined(__svr4__)
+    // On old SunOS call pthread_yield to yield a quantum.
     pthread_yield();
+#else
+    // On other platforms call sched_yield to yield a quantum.
+    sched_yield();
 #endif
 }
 
diff --git a/libgcc/unwind-dw2-fde-dip.c b/libgcc/unwind-dw2-fde-dip.c
index e1e566b..137dced 100644
--- a/libgcc/unwind-dw2-fde-dip.c
+++ b/libgcc/unwind-dw2-fde-dip.c
@@ -59,6 +59,12 @@
 
 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
     && defined(TARGET_DL_ITERATE_PHDR) \
+    && defined(__linux__)
+# define USE_PT_GNU_EH_FRAME
+#endif
+
+#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
+    && defined(TARGET_DL_ITERATE_PHDR) \
     && (defined(__DragonFly__) || defined(__FreeBSD__))
 # define ElfW __ElfN
 # define USE_PT_GNU_EH_FRAME
diff --git a/libgfortran/acinclude.m4 b/libgfortran/acinclude.m4
index ba890f9..30b8b1a6 100644
--- a/libgfortran/acinclude.m4
+++ b/libgfortran/acinclude.m4
@@ -100,7 +100,7 @@ void foo (void);
 	      [Define to 1 if the target supports #pragma weak])
   fi
   case "$host" in
-    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* )
+    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | *-*-musl* )
       AC_DEFINE(GTHREAD_USE_WEAK, 0,
 		[Define to 0 if the target shouldn't use #pragma weak])
       ;;
diff --git a/libgfortran/configure b/libgfortran/configure
index e1592f7..07542e1 100755
--- a/libgfortran/configure
+++ b/libgfortran/configure
@@ -26447,7 +26447,7 @@ $as_echo "#define SUPPORTS_WEAK 1" >>confdefs.h
 
   fi
   case "$host" in
-    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* )
+    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | *-*-musl* )
 
 $as_echo "#define GTHREAD_USE_WEAK 0" >>confdefs.h
 
diff --git a/libitm/config/arm/hwcap.cc b/libitm/config/arm/hwcap.cc
index a1c2cfd..ea8f023 100644
--- a/libitm/config/arm/hwcap.cc
+++ b/libitm/config/arm/hwcap.cc
@@ -40,7 +40,7 @@ int GTM_hwcap HIDDEN = 0
 
 #ifdef __linux__
 #include <unistd.h>
-#include <sys/fcntl.h>
+#include <fcntl.h>
 #include <elf.h>
 
 static void __attribute__((constructor))
diff --git a/libitm/config/linux/x86/tls.h b/libitm/config/linux/x86/tls.h
index e731ab7..54ad8b6 100644
--- a/libitm/config/linux/x86/tls.h
+++ b/libitm/config/linux/x86/tls.h
@@ -25,16 +25,19 @@
 #ifndef LIBITM_X86_TLS_H
 #define LIBITM_X86_TLS_H 1
 
-#if defined(__GLIBC_PREREQ) && __GLIBC_PREREQ(2, 10)
+#if defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 10)
 /* Use slots in the TCB head rather than __thread lookups.
    GLIBC has reserved words 10 through 13 for TM.  */
 #define HAVE_ARCH_GTM_THREAD 1
 #define HAVE_ARCH_GTM_THREAD_DISP 1
 #endif
+#endif
 
 #include "config/generic/tls.h"
 
-#if defined(__GLIBC_PREREQ) && __GLIBC_PREREQ(2, 10)
+#if defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 10)
 namespace GTM HIDDEN {
 
 #ifdef __x86_64__
@@ -101,5 +104,6 @@ static inline void set_abi_disp(struct abi_dispatch *x)
 
 } // namespace GTM
 #endif /* >= GLIBC 2.10 */
+#endif
 
 #endif // LIBITM_X86_TLS_H
diff --git a/libstdc++-v3/config/os/generic/os_defines.h b/libstdc++-v3/config/os/generic/os_defines.h
index 45bf52a..103ec0e 100644
--- a/libstdc++-v3/config/os/generic/os_defines.h
+++ b/libstdc++-v3/config/os/generic/os_defines.h
@@ -33,4 +33,9 @@
 // System-specific #define, typedefs, corrections, etc, go here.  This
 // file will come before all others.
 
+// Disable the weak reference logic in gthr.h for os/generic because it
+// is broken on every platform unless there is implementation specific
+// workaround in gthr-posix.h and at link-time for static linking.
+#define _GLIBCXX_GTHREAD_USE_WEAK 0
+
 #endif
diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
index 640199c..106134e 100644
--- a/libstdc++-v3/configure.host
+++ b/libstdc++-v3/configure.host
@@ -273,6 +273,9 @@ case "${host_os}" in
   freebsd*)
     os_include_dir="os/bsd/freebsd"
     ;;
+  linux-musl*)
+    os_include_dir="os/generic"
+    ;;
   gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
     if [ "$uclibc" = "yes" ]; then
       os_include_dir="os/uclibc"

Re: musl-cross-make / litecross improvements

[Szabolcs Nagy]

[-- Attachment #1: Type: text/plain, Size: 1452 bytes --]

* Rich Felker <dalias@libc.org> [2016-05-05 22:44:54 -0400]:
> not built at all for a c/c++ only build. Other langs are completely
> untested and probably don't work, but it would be nice to find out why
> and fix the ones that are practical to fix.

btw, for fortran --disable-libquadmath is not enough,
you need --disable-libquadmath-support too, see

https://gcc.gnu.org/install/configure.html

so i think those options should be recommended
together.

there are patches to make java and ada frontends
work (by alpine linux) but those are much less
tested than the c,c++ case.

> > Are you planning on supporting GCC 5.3? I may be able to contribute
> > some patches.
> 
> I suspect the same patches for 5.2 apply just fine, but I haven't
> taken the time to test yet. If you can confirm they work or tweak them
> so they work I'd be happy to add 5.3 support. Other versions I'd like

i think the powerpc patches wont apply, but
i have all my patches rebased for 5.3

> to support are 4.7.4 (last C-only, also last before some sketchy

likewise.

> optimizations were added) and 6.1.0, but in order to add a version it

likewise.

> should have proper support (at least the main musl patch with dynamic
> linker names, include paths, etc. fully ported) rather than just being
> enough to compile.

but i didnt test these patches with mcm, they don't have the
pie/fdpic/sh stuff and they might contain extra changes that
probably not everyone wants.

[-- Attachment #2: gcc-4.7.4.diff --]
[-- Type: text/x-diff, Size: 43559 bytes --]

diff --git a/config.sub b/config.sub
index 78176a4..c4a9252 100755
--- a/config.sub
+++ b/config.sub
@@ -125,6 +125,7 @@ esac
 maybe_os=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
 case $maybe_os in
   nto-qnx* | linux-gnu* | linux-android* | linux-dietlibc | linux-newlib* | \
+  linux-musl* | \
   linux-uclibc* | uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | \
   knetbsd*-gnu* | netbsd*-gnu* | \
   kopensolaris*-gnu* | \
@@ -1346,6 +1347,7 @@ case $os in
 	      | -cygwin* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
 	      | -mingw32* | -linux-gnu* | -linux-android* \
 	      | -linux-newlib* | -linux-uclibc* \
+	      | -linux-musl* \
 	      | -uxpv* | -beos* | -mpeix* | -udk* \
 	      | -interix* | -uwin* | -mks* | -rhapsody* | -darwin* | -opened* \
 	      | -openstep* | -oskit* | -conix* | -pw32* | -nonstopux* \
diff --git a/fixincludes/mkfixinc.sh b/fixincludes/mkfixinc.sh
index 89e8ab7..a3d0787 100755
--- a/fixincludes/mkfixinc.sh
+++ b/fixincludes/mkfixinc.sh
@@ -20,7 +20,8 @@ case $machine in
     powerpc-*-eabi*    | \
     powerpc-*-rtems*   | \
     powerpcle-*-eabisim* | \
-    powerpcle-*-eabi* )
+    powerpcle-*-eabi* | \
+    *-musl* )
 	#  IF there is no include fixing,
 	#  THEN create a no-op fixer and exit
 	(echo "#! /bin/sh" ; echo "exit 0" ) > ${target}
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index c42c087..36334fe 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -68,9 +68,9 @@ int in_sizeof;
 /* The level of nesting inside "typeof".  */
 int in_typeof;
 
-/* Nonzero if we've already printed a "missing braces around initializer"
-   message within this initializer.  */
-static int missing_braces_mentioned;
+/* Nonzero if we might need to print a "missing braces around
+   initializer" message within this initializer.  */
+static int found_missing_braces;
 
 static int require_constant_value;
 static int require_constant_elements;
@@ -6455,6 +6455,9 @@ static int constructor_nonconst;
 /* 1 if this constructor is erroneous so far.  */
 static int constructor_erroneous;
 
+/* 1 if this constructor is the universal zero initializer { 0 }.  */
+static int constructor_zeroinit;
+
 /* Structure for managing pending initializer elements, organized as an
    AVL tree.  */
 
@@ -6616,7 +6619,7 @@ start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
   constructor_stack = 0;
   constructor_range_stack = 0;
 
-  missing_braces_mentioned = 0;
+  found_missing_braces = 0;
 
   spelling_base = 0;
   spelling_size = 0;
@@ -6711,6 +6714,7 @@ really_start_incremental_init (tree type)
   constructor_type = type;
   constructor_incremental = 1;
   constructor_designated = 0;
+  constructor_zeroinit = 1;
   designator_depth = 0;
   designator_erroneous = 0;
 
@@ -6908,11 +6912,8 @@ push_init_level (int implicit, struct obstack * braced_init_obstack)
 	set_nonincremental_init (braced_init_obstack);
     }
 
-  if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
-    {
-      missing_braces_mentioned = 1;
-      warning_init (OPT_Wmissing_braces, "missing braces around initializer");
-    }
+  if (implicit == 1)
+    found_missing_braces = 1;
 
   if (TREE_CODE (constructor_type) == RECORD_TYPE
 	   || TREE_CODE (constructor_type) == UNION_TYPE)
@@ -7045,17 +7046,36 @@ pop_init_level (int implicit, struct obstack * braced_init_obstack)
 	}
     }
 
+  switch (VEC_length (constructor_elt, constructor_elements))
+    {
+    case 0:
+      /* Initialization with { } counts as zeroinit.  */
+      constructor_zeroinit = 1;
+      break;
+    case 1:
+      /* This might be zeroinit as well.  */
+      if (integer_zerop (VEC_index (constructor_elt, constructor_elements,
+	  0)->value))
+       constructor_zeroinit = 1;
+      break;
+    default:
+      /* If the constructor has more than one element, it can't be { 0 }.  */
+      constructor_zeroinit = 0;
+      break;
+    }
+
+  /* Warn when some structs are initialized with direct aggregation.  */
+  if (!implicit && found_missing_braces && warn_missing_braces
+      && !constructor_zeroinit)
+    warning_init (OPT_Wmissing_braces,
+		  "missing braces around initializer");
+
   /* Warn when some struct elements are implicitly initialized to zero.  */
   if (warn_missing_field_initializers
       && constructor_type
       && TREE_CODE (constructor_type) == RECORD_TYPE
       && constructor_unfilled_fields)
     {
-	bool constructor_zeroinit =
-	 (VEC_length (constructor_elt, constructor_elements) == 1
-	  && integer_zerop
-	      (VEC_index (constructor_elt, constructor_elements, 0)->value));
-
 	/* Do not warn for flexible array members or zero-length arrays.  */
 	while (constructor_unfilled_fields
 	       && (!DECL_SIZE (constructor_unfilled_fields)
@@ -8170,6 +8190,9 @@ process_init_element (struct c_expr value, bool implicit,
   designator_depth = 0;
   designator_erroneous = 0;
 
+  if (!implicit && value.value && !integer_zerop (value.value))
+    constructor_zeroinit = 0;
+
   /* Handle superfluous braces around string cst as in
      char x[] = {"foo"}; */
   if (string_flag
diff --git a/gcc/config.gcc b/gcc/config.gcc
index 9503b96..747eba3 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -522,7 +522,7 @@ case ${target} in
 esac
 
 # Common C libraries.
-tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3"
+tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3 LIBC_MUSL=4"
 
 # Common parts for widely ported systems.
 case ${target} in
@@ -625,6 +625,9 @@ case ${target} in
     *-*-*uclibc*)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
       ;;
+    *-*-*musl*)
+      tm_defines="$tm_defines DEFAULT_LIBC=LIBC_MUSL"
+      ;;
     *)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"
       ;;
@@ -2091,6 +2094,10 @@ powerpc-*-linux* | powerpc64-*-linux*)
 	    powerpc*-*-linux*paired*)
 		tm_file="${tm_file} rs6000/750cl.h" ;;
 	esac
+	case ${target} in
+	    *-linux*-musl*)
+		enable_secureplt=yes ;;
+	esac
 	if test x${enable_secureplt} = xyes; then
 		tm_file="rs6000/secureplt.h ${tm_file}"
 	fi
diff --git a/gcc/config/alpha/linux.h b/gcc/config/alpha/linux.h
index 38dbdb0..d475ca9 100644
--- a/gcc/config/alpha/linux.h
+++ b/gcc/config/alpha/linux.h
@@ -63,8 +63,16 @@ along with GCC; see the file COPYING3.  If not see
 
 #ifdef SINGLE_LIBC
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
+#define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
+#define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
+#define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
+#define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* Determine whether the entire c99 runtime is present in the
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index 80bd825..f49a04c 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -64,6 +64,23 @@
 #undef  GLIBC_DYNAMIC_LINKER
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3"
 
+/* For ARM musl currently supports four dynamic linkers:
+   - ld-musl-arm.so.1 - for the EABI-derived soft-float ABI
+   - ld-musl-armhf.so.1 - for the EABI-derived hard-float ABI
+   - ld-musl-armeb.so.1 - for the EABI-derived soft-float ABI, EB
+   - ld-musl-armebhf.so.1 - for the EABI-derived hard-float ABI, EB
+   musl does not support the legacy OABI mode.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, EL. */
+#undef  MUSL_DYNAMIC_LINKER
+#if TARGET_BIG_ENDIAN_DEFAULT
+#define MUSL_DYNAMIC_LINKER_E "%{mlittle-endian:;:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
+#endif
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
+
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */
 #undef  LINK_SPEC
diff --git a/gcc/config/glibc-stdint.h b/gcc/config/glibc-stdint.h
index 4f8fe07..9c33123 100644
--- a/gcc/config/glibc-stdint.h
+++ b/gcc/config/glibc-stdint.h
@@ -22,6 +22,12 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+/* Systems using musl libc should use this header and make sure
+   OPTION_MUSL is defined correctly before using the TYPE macros. */
+#ifndef OPTION_MUSL
+#define OPTION_MUSL 0
+#endif
+
 #define SIG_ATOMIC_TYPE "int"
 
 #define INT8_TYPE "signed char"
@@ -43,12 +49,12 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define UINT_LEAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "long long unsigned int")
 
 #define INT_FAST8_TYPE "signed char"
-#define INT_FAST16_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
-#define INT_FAST32_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
+#define INT_FAST16_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long int" : "int")
+#define INT_FAST32_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long int" : "int")
 #define INT_FAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "long long int")
 #define UINT_FAST8_TYPE "unsigned char"
-#define UINT_FAST16_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "unsigned int")
-#define UINT_FAST32_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "unsigned int")
+#define UINT_FAST16_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long unsigned int" : "unsigned int")
+#define UINT_FAST32_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long unsigned int" : "unsigned int")
 #define UINT_FAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "long long unsigned int")
 
 #define INTPTR_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
diff --git a/gcc/config/i386/linux.h b/gcc/config/i386/linux.h
index 73681fe..f907adf 100644
--- a/gcc/config/i386/linux.h
+++ b/gcc/config/i386/linux.h
@@ -22,3 +22,6 @@ along with GCC; see the file COPYING3.  If not see
 
 #define GNU_USER_LINK_EMULATION "elf_i386"
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-i386.so.1"
diff --git a/gcc/config/i386/linux64.h b/gcc/config/i386/linux64.h
index 5b0a212..cf361b2 100644
--- a/gcc/config/i386/linux64.h
+++ b/gcc/config/i386/linux64.h
@@ -31,3 +31,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define GLIBC_DYNAMIC_LINKER32 "/lib/ld-linux.so.2"
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld-linux-x86-64.so.2"
 #define GLIBC_DYNAMIC_LINKERX32 "/libx32/ld-linux-x32.so.2"
+
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-i386.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-x86_64.so.1"
+#undef MUSL_DYNAMIC_LINKERX32
+#define MUSL_DYNAMIC_LINKERX32 "/lib/ld-musl-x32.so.1"
diff --git a/gcc/config/i386/pmm_malloc.h b/gcc/config/i386/pmm_malloc.h
index 0a9f2e2..9f8db5c 100644
--- a/gcc/config/i386/pmm_malloc.h
+++ b/gcc/config/i386/pmm_malloc.h
@@ -27,12 +27,13 @@
 #include <stdlib.h>
 
 /* We can't depend on <stdlib.h> since the prototype of posix_memalign
-   may not be visible.  */
+   may not be visible and we can't pollute the namespace either.  */
 #ifndef __cplusplus
-extern int posix_memalign (void **, size_t, size_t);
+extern int _mm_posix_memalign (void **, size_t, size_t)
 #else
-extern "C" int posix_memalign (void **, size_t, size_t) throw ();
+extern "C" int _mm_posix_memalign (void **, size_t, size_t) throw ()
 #endif
+__asm__("posix_memalign");
 
 static __inline void *
 _mm_malloc (size_t size, size_t alignment)
@@ -42,7 +43,7 @@ _mm_malloc (size_t size, size_t alignment)
     return malloc (size);
   if (alignment == 2 || (sizeof (void *) == 8 && alignment == 4))
     alignment = sizeof (void *);
-  if (posix_memalign (&ptr, alignment, size) == 0)
+  if (_mm_posix_memalign (&ptr, alignment, size) == 0)
     return ptr;
   else
     return NULL;
diff --git a/gcc/config/linux.h b/gcc/config/linux.h
index fb459e6..d95f8c5 100644
--- a/gcc/config/linux.h
+++ b/gcc/config/linux.h
@@ -33,10 +33,14 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 #define GNU_USER_TARGET_OS_CPP_BUILTINS()			\
@@ -51,21 +55,25 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     } while (0)
 
 /* Determine which dynamic linker to use depending on whether GLIBC or
-   uClibc or Bionic is the default C library and whether
-   -muclibc or -mglibc or -mbionic has been passed to change the default.  */
+   uClibc or Bionic or musl is the default C library and whether
+   -muclibc or -mglibc or -mbionic or -mmusl has been passed to change
+   the default.  */
 
-#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LD1, LD2, LD3)	\
-  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:" LD1 "}}"
+#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LIBC4, LD1, LD2, LD3, LD4)	\
+  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:%{" LIBC4 ":" LD4 ";:" LD1 "}}}"
 
 #if DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", G, U, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", "mmusl", G, U, B, M)
 #elif DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", U, G, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", "mmusl", U, G, B, M)
 #elif DEFAULT_LIBC == LIBC_BIONIC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", B, G, U)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", "mmusl", B, G, U, M)
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mmusl", "mglibc", "muclibc", "mbionic", M, G, U, B)
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif /* DEFAULT_LIBC */
@@ -82,29 +90,106 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define BIONIC_DYNAMIC_LINKER32 "/system/bin/linker"
 #define BIONIC_DYNAMIC_LINKER64 "/system/bin/linker64"
 #define BIONIC_DYNAMIC_LINKERX32 "/system/bin/linkerx32"
+/* Should be redefined for each target that supports musl.  */
+#define MUSL_DYNAMIC_LINKER "/dev/null"
+#define MUSL_DYNAMIC_LINKER32 "/dev/null"
+#define MUSL_DYNAMIC_LINKER64 "/dev/null"
+#define MUSL_DYNAMIC_LINKERX32 "/dev/null"
 
 #define GNU_USER_DYNAMIC_LINKER						\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER,	\
-			 BIONIC_DYNAMIC_LINKER)
+			 BIONIC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
 #define GNU_USER_DYNAMIC_LINKER32					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, \
-			 BIONIC_DYNAMIC_LINKER32)
+			 BIONIC_DYNAMIC_LINKER32, MUSL_DYNAMIC_LINKER32)
 #define GNU_USER_DYNAMIC_LINKER64					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, \
-			 BIONIC_DYNAMIC_LINKER64)
+			 BIONIC_DYNAMIC_LINKER64, MUSL_DYNAMIC_LINKER64)
 #define GNU_USER_DYNAMIC_LINKERX32					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERX32, UCLIBC_DYNAMIC_LINKERX32, \
-			 BIONIC_DYNAMIC_LINKERX32)
+			 BIONIC_DYNAMIC_LINKERX32, MUSL_DYNAMIC_LINKERX32)
 
 /* Determine whether the entire c99 runtime
    is present in the runtime library.  */
 #undef TARGET_C99_FUNCTIONS
-#define TARGET_C99_FUNCTIONS (OPTION_GLIBC)
+#define TARGET_C99_FUNCTIONS (OPTION_GLIBC || OPTION_MUSL)
 
 /* Whether we have sincos that follows the GNU extension.  */
 #undef TARGET_HAS_SINCOS
-#define TARGET_HAS_SINCOS (OPTION_GLIBC || OPTION_BIONIC)
+#define TARGET_HAS_SINCOS (OPTION_GLIBC || OPTION_MUSL || OPTION_BIONIC)
 
 /* Whether we have Bionic libc runtime */
 #undef TARGET_HAS_BIONIC
 #define TARGET_HAS_BIONIC (OPTION_BIONIC)
+
+/* musl avoids problematic includes by rearranging the include directories.
+ * Unfortunately, this is mostly duplicated from cppdefault.c */
+#if DEFAULT_LIBC == LIBC_MUSL
+#define INCLUDE_DEFAULTS_MUSL_GPP			\
+    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },		\
+    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 1 },		\
+    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1,	\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },
+
+#ifdef LOCAL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_LOCAL			\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },		\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_LOCAL
+#endif
+
+#ifdef PREFIX_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_PREFIX
+#endif
+
+#ifdef CROSS_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_CROSS			\
+    { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#ifdef TOOL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_TOOL			\
+    { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_TOOL
+#endif
+
+#ifdef NATIVE_SYSTEM_HEADER_DIR
+#define INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 },	\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_NATIVE
+#endif
+
+#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
+# undef INCLUDE_DEFAULTS_MUSL_LOCAL
+# define INCLUDE_DEFAULTS_MUSL_LOCAL
+# undef INCLUDE_DEFAULTS_MUSL_NATIVE
+# define INCLUDE_DEFAULTS_MUSL_NATIVE
+#else
+# undef INCLUDE_DEFAULTS_MUSL_CROSS
+# define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#undef INCLUDE_DEFAULTS
+#define INCLUDE_DEFAULTS				\
+  {							\
+    INCLUDE_DEFAULTS_MUSL_GPP				\
+    INCLUDE_DEFAULTS_MUSL_LOCAL				\
+    INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    INCLUDE_DEFAULTS_MUSL_CROSS				\
+    INCLUDE_DEFAULTS_MUSL_TOOL				\
+    INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 },		\
+    { 0, 0, 0, 0, 0, 0 }				\
+  }
+#endif
diff --git a/gcc/config/linux.opt b/gcc/config/linux.opt
index ba6b9f83..f5e94a9 100644
--- a/gcc/config/linux.opt
+++ b/gcc/config/linux.opt
@@ -28,5 +28,9 @@ Target Report RejectNegative Var(linux_libc,LIBC_GLIBC) Negative(muclibc)
 Use GNU C library
 
 muclibc
-Target Report RejectNegative Var(linux_libc,LIBC_UCLIBC) Negative(mbionic)
+Target Report RejectNegative Var(linux_libc,LIBC_UCLIBC) Negative(mmusl)
 Use uClibc C library
+
+mmusl
+Target Report RejectNegative Var(linux_libc,LIBC_MUSL) Negative(mbionic)
+Use musl C library
diff --git a/gcc/config/microblaze/linux.h b/gcc/config/microblaze/linux.h
index 3c13fab..50c44dc 100644
--- a/gcc/config/microblaze/linux.h
+++ b/gcc/config/microblaze/linux.h
@@ -20,10 +20,20 @@
    <http://www.gnu.org/licenses/>.  */
 
 
-#define DYNAMIC_LINKER "/lib/ld.so.1"
+#define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
+
+#if TARGET_BIG_ENDIAN_DEFAULT == 0 /* LE */
+#define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:;:el}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{mlittle-endian:el}"
+#endif
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-microblaze" MUSL_DYNAMIC_LINKER_E ".so.1"
+
 #undef  SUBTARGET_EXTRA_SPECS
 #define SUBTARGET_EXTRA_SPECS \
-  { "dynamic_linker", DYNAMIC_LINKER }
+  { "dynamic_linker", GNU_USER_DYNAMIC_LINKER }
 
 #undef LINK_SPEC
 #define LINK_SPEC "%{shared:-shared} \
diff --git a/gcc/config/mips/linux.h b/gcc/config/mips/linux.h
index bce9c17..0467591 100644
--- a/gcc/config/mips/linux.h
+++ b/gcc/config/mips/linux.h
@@ -19,3 +19,6 @@ along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
 #define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-mips%{EL:el}%{msoft-float:-sf}.so.1"
diff --git a/gcc/config/mips/linux64.h b/gcc/config/mips/linux64.h
index 6e92719..58c7927 100644
--- a/gcc/config/mips/linux64.h
+++ b/gcc/config/mips/linux64.h
@@ -27,7 +27,14 @@ along with GCC; see the file COPYING3.  If not see
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld.so.1"
 #define GLIBC_DYNAMIC_LINKERN32 "/lib32/ld.so.1"
 #define UCLIBC_DYNAMIC_LINKERN32 "/lib32/ld-uClibc.so.0"
+
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-mips%{EL:el}%{msoft-float:-sf}.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-mips64%{EL:el}%{msoft-float:-sf}.so.1"
+#define MUSL_DYNAMIC_LINKERN32 "/lib/ld-musl-mipsn32%{EL:el}%{msoft-float:-sf}.so.1"
+
 #define BIONIC_DYNAMIC_LINKERN32 "/system/bin/linker32"
 #define GNU_USER_DYNAMIC_LINKERN32 \
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERN32, UCLIBC_DYNAMIC_LINKERN32, \
-			 BIONIC_DYNAMIC_LINKERN32)
+                         BIONIC_DYNAMIC_LINKERN32, MUSL_DYNAMIC_LINKERN32)
diff --git a/gcc/config/rs6000/linux.h b/gcc/config/rs6000/linux.h
index 3367274..ef1cb1c 100644
--- a/gcc/config/rs6000/linux.h
+++ b/gcc/config/rs6000/linux.h
@@ -29,17 +29,25 @@
 
 #ifdef SINGLE_LIBC
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
+#define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
+#define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
+#define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
+#define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* glibc has float and long double forms of math functions.  */
 #undef  TARGET_C99_FUNCTIONS
-#define TARGET_C99_FUNCTIONS (OPTION_GLIBC)
+#define TARGET_C99_FUNCTIONS (OPTION_GLIBC || OPTION_MUSL)
 
 /* Whether we have sincos that follows the GNU extension.  */
 #undef  TARGET_HAS_SINCOS
-#define TARGET_HAS_SINCOS (OPTION_GLIBC)
+#define TARGET_HAS_SINCOS (OPTION_GLIBC || OPTION_MUSL)
 
 #undef  TARGET_OS_CPP_BUILTINS
 #define TARGET_OS_CPP_BUILTINS()		\
diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index 7c516eb..d695038 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -162,20 +162,24 @@ extern int dot_symbols;
 #undef	ASM_DEFAULT_SPEC
 #undef	ASM_SPEC
 #undef	LINK_OS_LINUX_SPEC
+#undef	LINK_SECURE_PLT_SPEC
 
 #ifndef	RS6000_BI_ARCH
 #define	ASM_DEFAULT_SPEC "-mppc64"
 #define	ASM_SPEC	 "%(asm_spec64) %(asm_spec_common)"
 #define	LINK_OS_LINUX_SPEC "%(link_os_linux_spec64)"
+#define	LINK_SECURE_PLT_SPEC ""
 #else
 #if DEFAULT_ARCH64_P
 #define	ASM_DEFAULT_SPEC "-mppc%{!m32:64}"
 #define	ASM_SPEC	 "%{m32:%(asm_spec32)}%{!m32:%(asm_spec64)} %(asm_spec_common)"
 #define	LINK_OS_LINUX_SPEC "%{m32:%(link_os_linux_spec32)}%{!m32:%(link_os_linux_spec64)}"
+#define	LINK_SECURE_PLT_SPEC "%{m32: " LINK_SECURE_PLT_DEFAULT_SPEC "}"
 #else
 #define	ASM_DEFAULT_SPEC "-mppc%{m64:64}"
 #define	ASM_SPEC	 "%{!m64:%(asm_spec32)}%{m64:%(asm_spec64)} %(asm_spec_common)"
 #define	LINK_OS_LINUX_SPEC "%{!m64:%(link_os_linux_spec32)}%{m64:%(link_os_linux_spec64)}"
+#define	LINK_SECURE_PLT_SPEC "%{!m64: " LINK_SECURE_PLT_DEFAULT_SPEC "}"
 #endif
 #endif
 
@@ -295,17 +299,25 @@ extern int dot_symbols;
 
 #ifdef SINGLE_LIBC
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
+#define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
+#define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
+#define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
+#define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* glibc has float and long double forms of math functions.  */
 #undef  TARGET_C99_FUNCTIONS
-#define TARGET_C99_FUNCTIONS (OPTION_GLIBC)
+#define TARGET_C99_FUNCTIONS (OPTION_GLIBC || OPTION_MUSL)
 
 /* Whether we have sincos that follows the GNU extension.  */
 #undef  TARGET_HAS_SINCOS
-#define TARGET_HAS_SINCOS (OPTION_GLIBC)
+#define TARGET_HAS_SINCOS (OPTION_GLIBC || OPTION_MUSL)
 
 #undef  TARGET_OS_CPP_BUILTINS
 #define TARGET_OS_CPP_BUILTINS()			\
@@ -360,19 +372,32 @@ extern int dot_symbols;
 
 #define GLIBC_DYNAMIC_LINKER32 "/lib/ld.so.1"
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld64.so.1"
+
+#define MUSL_DYNAMIC_LINKER32 \
+  "/lib/ld-musl-powerpc" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
+#define MUSL_DYNAMIC_LINKER64 \
+  "/lib/ld-musl-powerpc64" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
+
 #define UCLIBC_DYNAMIC_LINKER32 "/lib/ld-uClibc.so.0"
 #define UCLIBC_DYNAMIC_LINKER64 "/lib/ld64-uClibc.so.0"
 #if DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{mmusl:" M ";:" U "}}"
 #elif DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{muclibc:" U ";:%{mmusl:" M ";:" G "}}"
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{muclibc:" U ";:" M "}}"
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif
 #define GNU_USER_DYNAMIC_LINKER32 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, \
+			 MUSL_DYNAMIC_LINKER32)
 #define GNU_USER_DYNAMIC_LINKER64 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, \
+			 MUSL_DYNAMIC_LINKER64)
 
 
 #define LINK_OS_LINUX_SPEC32 "-m elf32ppclinux %{!shared: %{!static: \
diff --git a/gcc/config/rs6000/secureplt.h b/gcc/config/rs6000/secureplt.h
index f41078d..2979d0b 100644
--- a/gcc/config/rs6000/secureplt.h
+++ b/gcc/config/rs6000/secureplt.h
@@ -18,3 +18,4 @@ along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
 #define CC1_SECURE_PLT_DEFAULT_SPEC "-msecure-plt"
+#define LINK_SECURE_PLT_DEFAULT_SPEC "--secure-plt"
diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
index aed2a29..6814bb5 100644
--- a/gcc/config/rs6000/sysv4.h
+++ b/gcc/config/rs6000/sysv4.h
@@ -567,6 +567,10 @@ extern int fixuplabelno;
 #define CC1_SECURE_PLT_DEFAULT_SPEC ""
 #endif
 
+#ifndef LINK_SECURE_PLT_DEFAULT_SPEC
+#define LINK_SECURE_PLT_DEFAULT_SPEC ""
+#endif
+
 /* Pass -G xxx to the compiler and set correct endian mode.  */
 #define	CC1_SPEC "%{G*} %(cc1_cpu) \
 %{mlittle|mlittle-endian: %(cc1_endian_little);           \
@@ -604,6 +608,7 @@ extern int fixuplabelno;
                : %(link_start_default)     }"
 
 #define LINK_START_DEFAULT_SPEC ""
+#define LINK_SECURE_PLT_SPEC LINK_SECURE_PLT_DEFAULT_SPEC
 
 #undef	LINK_SPEC
 #define	LINK_SPEC "\
@@ -612,6 +617,7 @@ extern int fixuplabelno;
 %(link_shlib) \
 %{!T*: %(link_start) } \
 %(link_target) \
+%{!static: %{!mbss-plt: %(link_secure_plt)}} \
 %(link_os)"
 
 /* Shared libraries are not default.  */
@@ -802,17 +808,27 @@ extern int fixuplabelno;
 
 #define LINK_START_LINUX_SPEC ""
 
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","")
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
 #define UCLIBC_DYNAMIC_LINKER "/lib/ld-uClibc.so.0"
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-powerpc" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
 #if DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{mmusl:" M ";:" U "}}"
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{muclibc:" U ";:" M "}}"
 #elif !defined (DEFAULT_LIBC) || DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{muclibc:" U ";:%{mmusl:" M ";:" G "}}"
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif
 #define GNU_USER_DYNAMIC_LINKER \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER, \
+			 MUSL_DYNAMIC_LINKER)
 
 #define LINK_OS_LINUX_SPEC "-m elf32ppclinux %{!shared: %{!static: \
   %{rdynamic:-export-dynamic} \
@@ -938,6 +954,7 @@ ncrtn.o%s"
   { "cc1_endian_little",	CC1_ENDIAN_LITTLE_SPEC },		\
   { "cc1_endian_default",	CC1_ENDIAN_DEFAULT_SPEC },		\
   { "cc1_secure_plt_default",	CC1_SECURE_PLT_DEFAULT_SPEC },		\
+  { "link_secure_plt",		LINK_SECURE_PLT_SPEC },			\
   { "cpp_os_ads",		CPP_OS_ADS_SPEC },			\
   { "cpp_os_yellowknife",	CPP_OS_YELLOWKNIFE_SPEC },		\
   { "cpp_os_mvme",		CPP_OS_MVME_SPEC },			\
@@ -990,3 +1007,74 @@ ncrtn.o%s"
 #define TARGET_USES_SYSV4_OPT 1
 
 #undef DBX_REGISTER_NUMBER
+
+/* Include order changes for musl, same as in generic linux.h.  */
+#if DEFAULT_LIBC == LIBC_MUSL
+#define INCLUDE_DEFAULTS_MUSL_GPP			\
+    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },		\
+    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 1 },		\
+    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1,	\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },
+
+#ifdef LOCAL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_LOCAL			\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },		\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_LOCAL
+#endif
+
+#ifdef PREFIX_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_PREFIX
+#endif
+
+#ifdef CROSS_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_CROSS			\
+    { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#ifdef TOOL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_TOOL			\
+    { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_TOOL
+#endif
+
+#ifdef NATIVE_SYSTEM_HEADER_DIR
+#define INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 },	\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_NATIVE
+#endif
+
+#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
+# undef INCLUDE_DEFAULTS_MUSL_LOCAL
+# define INCLUDE_DEFAULTS_MUSL_LOCAL
+# undef INCLUDE_DEFAULTS_MUSL_NATIVE
+# define INCLUDE_DEFAULTS_MUSL_NATIVE
+#else
+# undef INCLUDE_DEFAULTS_MUSL_CROSS
+# define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#undef INCLUDE_DEFAULTS
+#define INCLUDE_DEFAULTS				\
+  {							\
+    INCLUDE_DEFAULTS_MUSL_GPP				\
+    INCLUDE_DEFAULTS_MUSL_LOCAL				\
+    INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    INCLUDE_DEFAULTS_MUSL_CROSS				\
+    INCLUDE_DEFAULTS_MUSL_TOOL				\
+    INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 },		\
+    { 0, 0, 0, 0, 0, 0 }				\
+  }
+#endif
diff --git a/gcc/config/rs6000/sysv4le.h b/gcc/config/rs6000/sysv4le.h
index 1559777..d216357 100644
--- a/gcc/config/rs6000/sysv4le.h
+++ b/gcc/config/rs6000/sysv4le.h
@@ -34,3 +34,6 @@
 
 #undef	MULTILIB_DEFAULTS
 #define	MULTILIB_DEFAULTS { "mlittle", "mcall-sysv" }
+
+#undef MUSL_DYNAMIC_LINKER_E
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","le")
diff --git a/gcc/config/sh/linux.h b/gcc/config/sh/linux.h
index 3dad514..0dfc865 100644
--- a/gcc/config/sh/linux.h
+++ b/gcc/config/sh/linux.h
@@ -45,6 +45,27 @@ along with GCC; see the file COPYING3.  If not see
 
 #define TARGET_ASM_FILE_END file_end_indicate_exec_stack
 
+#if TARGET_ENDIAN_DEFAULT == MASK_LITTLE_ENDIAN
+#define MUSL_DYNAMIC_LINKER_E "%{mb:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{!ml:eb}"
+#endif
+
+#if TARGET_CPU_DEFAULT & (MASK_HARD_SH2A_DOUBLE | MASK_SH4)
+/* "-nofpu" if any nofpu option is specified.  */
+#define MUSL_DYNAMIC_LINKER_FP \
+  "%{m1|m2|m2a-nofpu|m3|m4-nofpu|m4-100-nofpu|m4-200-nofpu|m4-300-nofpu|" \
+  "m4-340|m4-400|m4-500|m4al:-nofpu}"
+#else
+/* "-nofpu" if none of the hard fpu options are specified.  */
+#define MUSL_DYNAMIC_LINKER_FP "%{m2a|m4|m4-100|m4-200|m4-300|m4a:;:-nofpu}"
+#endif
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-sh" MUSL_DYNAMIC_LINKER_E MUSL_DYNAMIC_LINKER_FP \
+  "%{mfdpic:-fdpic}.so.1"
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
 
 #undef SUBTARGET_LINK_EMUL_SUFFIX
diff --git a/gcc/configure b/gcc/configure
index 0d8c5e7..695e7c4 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -26791,6 +26791,9 @@ if test "${gcc_cv_libc_provides_ssp+set}" = set; then :
 else
   gcc_cv_libc_provides_ssp=no
     case "$target" in
+       *-*-musl*)
+	 # All versions of musl provide stack protector
+	 gcc_cv_libc_provides_ssp=yes;;
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)
       # glibc 2.4 and later provides __stack_chk_fail and
       # either __stack_chk_guard, or TLS access to stack guard canary.
@@ -26824,6 +26827,7 @@ else
 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now
 	 # simply assert that glibc does provide this, which is true for all
 	 # realistically usable GNU/Hurd configurations.
+	 # All supported versions of musl provide it as well
 	 gcc_cv_libc_provides_ssp=yes;;
        *-*-darwin* | *-*-freebsd*)
 	 ac_fn_c_check_func "$LINENO" "__stack_chk_fail" "ac_cv_func___stack_chk_fail"
@@ -26906,6 +26910,9 @@ case "$target" in
       gcc_cv_target_dl_iterate_phdr=no
     fi
     ;;
+  *-linux-musl*)
+    gcc_cv_target_dl_iterate_phdr=yes
+    ;;
 esac
 
 if test x$gcc_cv_target_dl_iterate_phdr = xyes; then
diff --git a/gcc/configure.ac b/gcc/configure.ac
index a78a1d7..b6425ef 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -4669,6 +4669,9 @@ AC_CACHE_CHECK(__stack_chk_fail in target C library,
       gcc_cv_libc_provides_ssp,
       [gcc_cv_libc_provides_ssp=no
     case "$target" in
+       *-*-musl*)
+	 # All versions of musl provide stack protector
+	 gcc_cv_libc_provides_ssp=yes;;
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)
       [# glibc 2.4 and later provides __stack_chk_fail and
       # either __stack_chk_guard, or TLS access to stack guard canary.
@@ -4702,6 +4705,7 @@ AC_CACHE_CHECK(__stack_chk_fail in target C library,
 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now
 	 # simply assert that glibc does provide this, which is true for all
 	 # realistically usable GNU/Hurd configurations.
+	 # All supported versions of musl provide it as well
 	 gcc_cv_libc_provides_ssp=yes;;
        *-*-darwin* | *-*-freebsd*)
 	 AC_CHECK_FUNC(__stack_chk_fail,[gcc_cv_libc_provides_ssp=yes],
@@ -4767,6 +4771,9 @@ case "$target" in
       gcc_cv_target_dl_iterate_phdr=no
     fi
     ;;
+  *-linux-musl*)
+    gcc_cv_target_dl_iterate_phdr=yes
+    ;;
 esac
 GCC_TARGET_TEMPLATE([TARGET_DL_ITERATE_PHDR])
 if test x$gcc_cv_target_dl_iterate_phdr = xyes; then
diff --git a/gcc/cp/cfns.gperf b/gcc/cp/cfns.gperf
index ef1ed08..721c741 100644
--- a/gcc/cp/cfns.gperf
+++ b/gcc/cp/cfns.gperf
@@ -20,9 +20,7 @@ along with GCC; see the file COPYING3.  If not see
 __inline
 #endif
 static unsigned int hash (const char *, unsigned int);
-#ifdef __GNUC__
-__inline
-#endif
+static inline
 const char * libc_name_p (const char *, unsigned int);
 %}
 %%
diff --git a/gcc/cp/cfns.h b/gcc/cp/cfns.h
index 62cdfab..4a27a26 100644
--- a/gcc/cp/cfns.h
+++ b/gcc/cp/cfns.h
@@ -51,9 +51,7 @@ along with GCC; see the file COPYING3.  If not see
 __inline
 #endif
 static unsigned int hash (const char *, unsigned int);
-#ifdef __GNUC__
-__inline
-#endif
+static inline
 const char * libc_name_p (const char *, unsigned int);
 /* maximum key range = 391, duplicates = 0 */
 
@@ -122,12 +120,7 @@ hash (register const char *str, register unsigned int len)
   return hval + asso_values[(unsigned char)str[len - 1]];
 }
 
-#ifdef __GNUC__
-__inline
-#ifdef __GNUC_STDC_INLINE__
-__attribute__ ((__gnu_inline__))
-#endif
-#endif
+static inline
 const char *
 libc_name_p (register const char *str, register unsigned int len)
 {
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 625fef2..159615f 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -595,7 +595,7 @@ Objective-C and Objective-C++ Dialects}.
 -mcpu=@var{cpu}}
 
 @emph{GNU/Linux Options}
-@gccoptlist{-mglibc -muclibc -mbionic -mandroid @gol
+@gccoptlist{-mglibc -muclibc -mmusl -mbionic -mandroid @gol
 -tno-android-cc -tno-android-ld}
 
 @emph{H8/300 Options}
@@ -12879,13 +12879,19 @@ These @samp{-m} options are defined for GNU/Linux targets:
 @item -mglibc
 @opindex mglibc
 Use the GNU C library.  This is the default except
-on @samp{*-*-linux-*uclibc*} and @samp{*-*-linux-*android*} targets.
+on @samp{*-*-linux-*uclibc*}, @samp{*-*-linux-*musl*} and
+@samp{*-*-linux-*android*} targets.
 
 @item -muclibc
 @opindex muclibc
 Use uClibc C library.  This is the default on
 @samp{*-*-linux-*uclibc*} targets.
 
+@item -mmusl
+@opindex mmusl
+Use the musl C library.  This is the default on
+@samp{*-*-linux-*musl*} targets.
+
 @item -mbionic
 @opindex mbionic
 Use Bionic C library.  This is the default on
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 939dcc8..a3b0912 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -603,7 +603,7 @@ proper position among the other output files.  */
 
 #ifndef LINK_SSP_SPEC
 #ifdef TARGET_LIBC_PROVIDES_SSP
-#define LINK_SSP_SPEC "%{fstack-protector:}"
+#define LINK_SSP_SPEC "%{fstack-protector|fstack-protector-all:-lssp_nonshared}"
 #else
 #define LINK_SSP_SPEC "%{fstack-protector|fstack-protector-all:-lssp_nonshared -lssp}"
 #endif
diff --git a/libgcc/config/arm/linux-atomic-64bit.c b/libgcc/config/arm/linux-atomic-64bit.c
index af94c7f..36570e5 100644
--- a/libgcc/config/arm/linux-atomic-64bit.c
+++ b/libgcc/config/arm/linux-atomic-64bit.c
@@ -33,7 +33,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    kernels; we check for that in an init section and bail out rather
    unceremoneously.  */
 
-extern unsigned int __write (int fd, const void *buf, unsigned int count);
+extern int write (int fd, const void *buf, unsigned int count);
 extern void abort (void);
 
 /* Kernel helper for compare-and-exchange.  */
@@ -56,7 +56,7 @@ static void __check_for_sync8_kernelhelper (void)
 	 for the user - I'm not sure I can rely on much else being
 	 available at this point, so do the same as generic-morestack.c
 	 write () and abort ().  */
-      __write (2 /* stderr.  */, err, sizeof (err));
+      write (2 /* stderr.  */, err, sizeof (err));
       abort ();
     }
 };
diff --git a/libgcc/config/rs6000/linux-unwind.h b/libgcc/config/rs6000/linux-unwind.h
index 13bf413..9cc3af1 100644
--- a/libgcc/config/rs6000/linux-unwind.h
+++ b/libgcc/config/rs6000/linux-unwind.h
@@ -182,6 +182,7 @@ get_regs (struct _Unwind_Context *context)
 static long
 ppc_linux_aux_vector (long which)
 {
+#ifdef __GLIBC__
   /* __libc_stack_end holds the original stack passed to a process.  */
   extern long *__libc_stack_end;
   long argc;
@@ -206,6 +207,10 @@ ppc_linux_aux_vector (long which)
     if (auxp->a_type == which)
       return auxp->a_val;
   return 0;
+#else
+  extern unsigned long getauxval(unsigned long);
+  return getauxval(which);
+#endif
 }
 
 /* Do code reading to identify a signal frame, and set the frame
diff --git a/libgcc/unwind-dw2-fde-dip.c b/libgcc/unwind-dw2-fde-dip.c
index a048495..0a71e31 100644
--- a/libgcc/unwind-dw2-fde-dip.c
+++ b/libgcc/unwind-dw2-fde-dip.c
@@ -54,6 +54,12 @@
 #endif
 
 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
+    && defined(TARGET_DL_ITERATE_PHDR) \
+    && defined(__linux__)
+# define USE_PT_GNU_EH_FRAME
+#endif
+
+#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
     && defined(__FreeBSD__) && __FreeBSD__ >= 7
 # define ElfW __ElfN
 # define USE_PT_GNU_EH_FRAME
diff --git a/libgfortran/acinclude.m4 b/libgfortran/acinclude.m4
index 645b248..73203b9 100644
--- a/libgfortran/acinclude.m4
+++ b/libgfortran/acinclude.m4
@@ -99,7 +99,7 @@ void foo (void);
 	      [Define to 1 if the target supports #pragma weak])
   fi
   case "$host" in
-    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | alpha*-dec-osf* )
+    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | alpha*-dec-osf* | *-*-musl* )
       AC_DEFINE(GTHREAD_USE_WEAK, 0,
 		[Define to 0 if the target shouldn't use #pragma weak])
       ;;
diff --git a/libgfortran/configure b/libgfortran/configure
index 227f556..c4abe04 100755
--- a/libgfortran/configure
+++ b/libgfortran/configure
@@ -25564,7 +25564,7 @@ $as_echo "#define SUPPORTS_WEAK 1" >>confdefs.h
 
   fi
   case "$host" in
-    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | alpha*-dec-osf* )
+    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | alpha*-dec-osf* | *-*-musl* )
 
 $as_echo "#define GTHREAD_USE_WEAK 0" >>confdefs.h
 
diff --git a/libitm/config/arm/hwcap.cc b/libitm/config/arm/hwcap.cc
index 007c10e..e35dbfb 100644
--- a/libitm/config/arm/hwcap.cc
+++ b/libitm/config/arm/hwcap.cc
@@ -40,7 +40,7 @@ int GTM_hwcap HIDDEN = 0
 
 #ifdef __linux__
 #include <unistd.h>
-#include <sys/fcntl.h>
+#include <fcntl.h>
 #include <elf.h>
 
 static void __attribute__((constructor))
diff --git a/libitm/config/linux/x86/tls.h b/libitm/config/linux/x86/tls.h
index 01f7c27..7fcafa8 100644
--- a/libitm/config/linux/x86/tls.h
+++ b/libitm/config/linux/x86/tls.h
@@ -25,16 +25,19 @@
 #ifndef LIBITM_X86_TLS_H
 #define LIBITM_X86_TLS_H 1
 
-#if defined(__GLIBC_PREREQ) && __GLIBC_PREREQ(2, 10)
+#if defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 10)
 /* Use slots in the TCB head rather than __thread lookups.
    GLIBC has reserved words 10 through 13 for TM.  */
 #define HAVE_ARCH_GTM_THREAD 1
 #define HAVE_ARCH_GTM_THREAD_DISP 1
 #endif
+#endif
 
 #include "config/generic/tls.h"
 
-#if defined(__GLIBC_PREREQ) && __GLIBC_PREREQ(2, 10)
+#if defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 10)
 namespace GTM HIDDEN {
 
 #ifdef __x86_64__
@@ -101,5 +104,6 @@ static inline void set_abi_disp(struct abi_dispatch *x)
 
 } // namespace GTM
 #endif /* >= GLIBC 2.10 */
+#endif
 
 #endif // LIBITM_X86_TLS_H
diff --git a/libstdc++-v3/config/os/generic/os_defines.h b/libstdc++-v3/config/os/generic/os_defines.h
index 3199bf3..b8d7c16 100644
--- a/libstdc++-v3/config/os/generic/os_defines.h
+++ b/libstdc++-v3/config/os/generic/os_defines.h
@@ -33,4 +33,9 @@
 // System-specific #define, typedefs, corrections, etc, go here.  This
 // file will come before all others.
 
+// Disable the weak reference logic in gthr.h for os/generic because it
+// is broken on every platform unless there is implementation specific
+// workaround in gthr-posix.h and at link-time for static linking.
+#define _GLIBCXX_GTHREAD_USE_WEAK 0
+
 #endif
diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
index b0e2cd9..df79771 100644
--- a/libstdc++-v3/configure.host
+++ b/libstdc++-v3/configure.host
@@ -242,6 +242,9 @@ case "${host_os}" in
   freebsd*)
     os_include_dir="os/bsd/freebsd"
     ;;
+  linux-musl*)
+    os_include_dir="os/generic"
+    ;;
   gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
     if [ "$uclibc" = "yes" ]; then
       os_include_dir="os/uclibc"

[-- Attachment #3: gcc-5.3.0.diff --]
[-- Type: text/x-diff, Size: 37442 bytes --]

diff --git a/fixincludes/mkfixinc.sh b/fixincludes/mkfixinc.sh
index 6653fedb..0d96c8c 100755
--- a/fixincludes/mkfixinc.sh
+++ b/fixincludes/mkfixinc.sh
@@ -19,7 +19,8 @@ case $machine in
     powerpc-*-eabi*    | \
     powerpc-*-rtems*   | \
     powerpcle-*-eabisim* | \
-    powerpcle-*-eabi* )
+    powerpcle-*-eabi* | \
+    *-musl* )
 	#  IF there is no include fixing,
 	#  THEN create a no-op fixer and exit
 	(echo "#! /bin/sh" ; echo "exit 0" ) > ${target}
diff --git a/gcc/config.gcc b/gcc/config.gcc
index c835734..046121c 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -575,7 +575,7 @@ case ${target} in
 esac
 
 # Common C libraries.
-tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3"
+tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3 LIBC_MUSL=4"
 
 # 32-bit x86 processors supported by --with-arch=.  Each processor
 # MUST be separated by exactly one space.
@@ -720,6 +720,9 @@ case ${target} in
     *-*-*uclibc*)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
       ;;
+    *-*-*musl*)
+      tm_defines="$tm_defines DEFAULT_LIBC=LIBC_MUSL"
+      ;;
     *)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"
       ;;
@@ -2413,6 +2416,10 @@ powerpc*-*-linux*)
 	    powerpc*-*-linux*paired*)
 		tm_file="${tm_file} rs6000/750cl.h" ;;
 	esac
+	case ${target} in
+	    *-linux*-musl*)
+		enable_secureplt=yes ;;
+	esac
 	if test x${enable_secureplt} = xyes; then
 		tm_file="rs6000/secureplt.h ${tm_file}"
 	fi
diff --git a/gcc/config/aarch64/aarch64-linux.h b/gcc/config/aarch64/aarch64-linux.h
index 257acf0..c51c8b2 100644
--- a/gcc/config/aarch64/aarch64-linux.h
+++ b/gcc/config/aarch64/aarch64-linux.h
@@ -23,6 +23,9 @@
 
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"
 
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"
+
 #undef  ASAN_CC1_SPEC
 #define ASAN_CC1_SPEC "%{%:sanitize(address):-funwind-tables}"
 
diff --git a/gcc/config/alpha/linux.h b/gcc/config/alpha/linux.h
index c567f43..475ea06 100644
--- a/gcc/config/alpha/linux.h
+++ b/gcc/config/alpha/linux.h
@@ -61,10 +61,14 @@ along with GCC; see the file COPYING3.  If not see
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* Determine what functions are present at the runtime;
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index e9d65dc..f12e6bd 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -77,6 +77,23 @@
     %{mfloat-abi=soft*:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "} \
     %{!mfloat-abi=*:" GLIBC_DYNAMIC_LINKER_DEFAULT "}"
 
+/* For ARM musl currently supports four dynamic linkers:
+   - ld-musl-arm.so.1 - for the EABI-derived soft-float ABI
+   - ld-musl-armhf.so.1 - for the EABI-derived hard-float ABI
+   - ld-musl-armeb.so.1 - for the EABI-derived soft-float ABI, EB
+   - ld-musl-armebhf.so.1 - for the EABI-derived hard-float ABI, EB
+   musl does not support the legacy OABI mode.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, EL. */
+#undef  MUSL_DYNAMIC_LINKER
+#if TARGET_BIG_ENDIAN_DEFAULT
+#define MUSL_DYNAMIC_LINKER_E "%{mlittle-endian:;:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
+#endif
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
+
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */
 #undef  LINK_SPEC
diff --git a/gcc/config/glibc-stdint.h b/gcc/config/glibc-stdint.h
index 3fc67dc..98f4f04 100644
--- a/gcc/config/glibc-stdint.h
+++ b/gcc/config/glibc-stdint.h
@@ -22,6 +22,12 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+/* Systems using musl libc should use this header and make sure
+   OPTION_MUSL is defined correctly before using the TYPE macros. */
+#ifndef OPTION_MUSL
+#define OPTION_MUSL 0
+#endif
+
 #define SIG_ATOMIC_TYPE "int"
 
 #define INT8_TYPE "signed char"
@@ -43,12 +49,12 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define UINT_LEAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "long long unsigned int")
 
 #define INT_FAST8_TYPE "signed char"
-#define INT_FAST16_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
-#define INT_FAST32_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
+#define INT_FAST16_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long int" : "int")
+#define INT_FAST32_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long int" : "int")
 #define INT_FAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "long long int")
 #define UINT_FAST8_TYPE "unsigned char"
-#define UINT_FAST16_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "unsigned int")
-#define UINT_FAST32_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "unsigned int")
+#define UINT_FAST16_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long unsigned int" : "unsigned int")
+#define UINT_FAST32_TYPE (LONG_TYPE_SIZE == 64 && !OPTION_MUSL ? "long unsigned int" : "unsigned int")
 #define UINT_FAST64_TYPE (LONG_TYPE_SIZE == 64 ? "long unsigned int" : "long long unsigned int")
 
 #define INTPTR_TYPE (LONG_TYPE_SIZE == 64 ? "long int" : "int")
diff --git a/gcc/config/i386/linux.h b/gcc/config/i386/linux.h
index a100963..385aefd 100644
--- a/gcc/config/i386/linux.h
+++ b/gcc/config/i386/linux.h
@@ -21,3 +21,6 @@ along with GCC; see the file COPYING3.  If not see
 
 #define GNU_USER_LINK_EMULATION "elf_i386"
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-i386.so.1"
diff --git a/gcc/config/i386/linux64.h b/gcc/config/i386/linux64.h
index a27d3be..e300480 100644
--- a/gcc/config/i386/linux64.h
+++ b/gcc/config/i386/linux64.h
@@ -30,3 +30,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define GLIBC_DYNAMIC_LINKER32 "/lib/ld-linux.so.2"
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld-linux-x86-64.so.2"
 #define GLIBC_DYNAMIC_LINKERX32 "/libx32/ld-linux-x32.so.2"
+
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-i386.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-x86_64.so.1"
+#undef MUSL_DYNAMIC_LINKERX32
+#define MUSL_DYNAMIC_LINKERX32 "/lib/ld-musl-x32.so.1"
diff --git a/gcc/config/i386/pmm_malloc.h b/gcc/config/i386/pmm_malloc.h
index 901001b..0696c20 100644
--- a/gcc/config/i386/pmm_malloc.h
+++ b/gcc/config/i386/pmm_malloc.h
@@ -27,12 +27,13 @@
 #include <stdlib.h>
 
 /* We can't depend on <stdlib.h> since the prototype of posix_memalign
-   may not be visible.  */
+   may not be visible and we can't pollute the namespace either.  */
 #ifndef __cplusplus
-extern int posix_memalign (void **, size_t, size_t);
+extern int _mm_posix_memalign (void **, size_t, size_t)
 #else
-extern "C" int posix_memalign (void **, size_t, size_t) throw ();
+extern "C" int _mm_posix_memalign (void **, size_t, size_t) throw ()
 #endif
+__asm__("posix_memalign");
 
 static __inline void *
 _mm_malloc (size_t size, size_t alignment)
@@ -42,7 +43,7 @@ _mm_malloc (size_t size, size_t alignment)
     return malloc (size);
   if (alignment == 2 || (sizeof (void *) == 8 && alignment == 4))
     alignment = sizeof (void *);
-  if (posix_memalign (&ptr, alignment, size) == 0)
+  if (_mm_posix_memalign (&ptr, alignment, size) == 0)
     return ptr;
   else
     return NULL;
diff --git a/gcc/config/linux.c b/gcc/config/linux.c
index 2081e34..37515bf 100644
--- a/gcc/config/linux.c
+++ b/gcc/config/linux.c
@@ -26,7 +26,7 @@ along with GCC; see the file COPYING3.  If not see
 bool
 linux_libc_has_function (enum function_class fn_class)
 {
-  if (OPTION_GLIBC)
+  if (OPTION_GLIBC || OPTION_MUSL)
     return true;
   if (OPTION_BIONIC)
     if (fn_class == function_c94
diff --git a/gcc/config/linux.h b/gcc/config/linux.h
index 857389a..a2094ce 100644
--- a/gcc/config/linux.h
+++ b/gcc/config/linux.h
@@ -32,10 +32,14 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 #define GNU_USER_TARGET_OS_CPP_BUILTINS()			\
@@ -50,21 +54,25 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     } while (0)
 
 /* Determine which dynamic linker to use depending on whether GLIBC or
-   uClibc or Bionic is the default C library and whether
-   -muclibc or -mglibc or -mbionic has been passed to change the default.  */
+   uClibc or Bionic or musl is the default C library and whether
+   -muclibc or -mglibc or -mbionic or -mmusl has been passed to change
+   the default.  */
 
-#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LD1, LD2, LD3)	\
-  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:" LD1 "}}"
+#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LIBC4, LD1, LD2, LD3, LD4)	\
+  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:%{" LIBC4 ":" LD4 ";:" LD1 "}}}"
 
 #if DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", G, U, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", "mmusl", G, U, B, M)
 #elif DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", U, G, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", "mmusl", U, G, B, M)
 #elif DEFAULT_LIBC == LIBC_BIONIC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", B, G, U)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", "mmusl", B, G, U, M)
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mmusl", "mglibc", "muclibc", "mbionic", M, G, U, B)
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif /* DEFAULT_LIBC */
@@ -81,24 +89,101 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define BIONIC_DYNAMIC_LINKER32 "/system/bin/linker"
 #define BIONIC_DYNAMIC_LINKER64 "/system/bin/linker64"
 #define BIONIC_DYNAMIC_LINKERX32 "/system/bin/linkerx32"
+/* Should be redefined for each target that supports musl.  */
+#define MUSL_DYNAMIC_LINKER "/dev/null"
+#define MUSL_DYNAMIC_LINKER32 "/dev/null"
+#define MUSL_DYNAMIC_LINKER64 "/dev/null"
+#define MUSL_DYNAMIC_LINKERX32 "/dev/null"
 
 #define GNU_USER_DYNAMIC_LINKER						\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER,	\
-			 BIONIC_DYNAMIC_LINKER)
+			 BIONIC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
 #define GNU_USER_DYNAMIC_LINKER32					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, \
-			 BIONIC_DYNAMIC_LINKER32)
+			 BIONIC_DYNAMIC_LINKER32, MUSL_DYNAMIC_LINKER32)
 #define GNU_USER_DYNAMIC_LINKER64					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, \
-			 BIONIC_DYNAMIC_LINKER64)
+			 BIONIC_DYNAMIC_LINKER64, MUSL_DYNAMIC_LINKER64)
 #define GNU_USER_DYNAMIC_LINKERX32					\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERX32, UCLIBC_DYNAMIC_LINKERX32, \
-			 BIONIC_DYNAMIC_LINKERX32)
+			 BIONIC_DYNAMIC_LINKERX32, MUSL_DYNAMIC_LINKERX32)
 
 /* Whether we have Bionic libc runtime */
 #undef TARGET_HAS_BIONIC
 #define TARGET_HAS_BIONIC (OPTION_BIONIC)
 
+/* musl avoids problematic includes by rearranging the include directories.
+ * Unfortunately, this is mostly duplicated from cppdefault.c */
+#if DEFAULT_LIBC == LIBC_MUSL
+#define INCLUDE_DEFAULTS_MUSL_GPP			\
+    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },		\
+    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 1 },		\
+    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1,	\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },
+
+#ifdef LOCAL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_LOCAL			\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },		\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_LOCAL
+#endif
+
+#ifdef PREFIX_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_PREFIX
+#endif
+
+#ifdef CROSS_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_CROSS			\
+    { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#ifdef TOOL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_TOOL			\
+    { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_TOOL
+#endif
+
+#ifdef NATIVE_SYSTEM_HEADER_DIR
+#define INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 },	\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_NATIVE
+#endif
+
+#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
+# undef INCLUDE_DEFAULTS_MUSL_LOCAL
+# define INCLUDE_DEFAULTS_MUSL_LOCAL
+# undef INCLUDE_DEFAULTS_MUSL_NATIVE
+# define INCLUDE_DEFAULTS_MUSL_NATIVE
+#else
+# undef INCLUDE_DEFAULTS_MUSL_CROSS
+# define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#undef INCLUDE_DEFAULTS
+#define INCLUDE_DEFAULTS				\
+  {							\
+    INCLUDE_DEFAULTS_MUSL_GPP				\
+    INCLUDE_DEFAULTS_MUSL_LOCAL				\
+    INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    INCLUDE_DEFAULTS_MUSL_CROSS				\
+    INCLUDE_DEFAULTS_MUSL_TOOL				\
+    INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 },		\
+    { 0, 0, 0, 0, 0, 0 }				\
+  }
+#endif
+
 #if (DEFAULT_LIBC == LIBC_UCLIBC) && defined (SINGLE_LIBC) /* uClinux */
 /* This is a *uclinux* target.  We don't define below macros to normal linux
    versions, because doing so would require *uclinux* targets to include
diff --git a/gcc/config/linux.opt b/gcc/config/linux.opt
index c054338..ef055a7 100644
--- a/gcc/config/linux.opt
+++ b/gcc/config/linux.opt
@@ -28,5 +28,9 @@ Target Report RejectNegative Var(linux_libc,LIBC_GLIBC) Negative(muclibc)
 Use GNU C library
 
 muclibc
-Target Report RejectNegative Var(linux_libc,LIBC_UCLIBC) Negative(mbionic)
+Target Report RejectNegative Var(linux_libc,LIBC_UCLIBC) Negative(mmusl)
 Use uClibc C library
+
+mmusl
+Target Report RejectNegative Var(linux_libc,LIBC_MUSL) Negative(mbionic)
+Use musl C library
diff --git a/gcc/config/microblaze/linux.h b/gcc/config/microblaze/linux.h
index 655a70f..a8a3f3e 100644
--- a/gcc/config/microblaze/linux.h
+++ b/gcc/config/microblaze/linux.h
@@ -28,10 +28,20 @@
 #undef TLS_NEEDS_GOT
 #define TLS_NEEDS_GOT 1
 
-#define DYNAMIC_LINKER "/lib/ld.so.1"
+#define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
+
+#if TARGET_BIG_ENDIAN_DEFAULT == 0 /* LE */
+#define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:;:el}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{mlittle-endian:el}"
+#endif
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-microblaze" MUSL_DYNAMIC_LINKER_E ".so.1"
+
 #undef  SUBTARGET_EXTRA_SPECS
 #define SUBTARGET_EXTRA_SPECS \
-  { "dynamic_linker", DYNAMIC_LINKER }
+  { "dynamic_linker", GNU_USER_DYNAMIC_LINKER }
 
 #undef LINK_SPEC
 #define LINK_SPEC "%{shared:-shared} \
diff --git a/gcc/config/mips/linux.h b/gcc/config/mips/linux.h
index 91df261..fb358e2 100644
--- a/gcc/config/mips/linux.h
+++ b/gcc/config/mips/linux.h
@@ -37,7 +37,13 @@ along with GCC; see the file COPYING3.  If not see
 #define UCLIBC_DYNAMIC_LINKERN32 \
   "%{mnan=2008:/lib32/ld-uClibc-mipsn8.so.0;:/lib32/ld-uClibc.so.0}"
 
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-mips%{EL:el}%{msoft-float:-sf}.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-mips64%{EL:el}%{msoft-float:-sf}.so.1"
+#define MUSL_DYNAMIC_LINKERN32 "/lib/ld-musl-mipsn32%{EL:el}%{msoft-float:-sf}.so.1"
+
 #define BIONIC_DYNAMIC_LINKERN32 "/system/bin/linker32"
 #define GNU_USER_DYNAMIC_LINKERN32 \
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERN32, UCLIBC_DYNAMIC_LINKERN32, \
-                         BIONIC_DYNAMIC_LINKERN32)
+                         BIONIC_DYNAMIC_LINKERN32, MUSL_DYNAMIC_LINKERN32)
diff --git a/gcc/config/rs6000/linux.h b/gcc/config/rs6000/linux.h
index fe0ebd6..a68ff69 100644
--- a/gcc/config/rs6000/linux.h
+++ b/gcc/config/rs6000/linux.h
@@ -30,10 +30,14 @@
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* Determine what functions are present at the runtime;
diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index 0879e7e..5ed892c 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -174,20 +174,24 @@ extern int dot_symbols;
 #undef	ASM_DEFAULT_SPEC
 #undef	ASM_SPEC
 #undef	LINK_OS_LINUX_SPEC
+#undef	LINK_SECURE_PLT_SPEC
 
 #ifndef	RS6000_BI_ARCH
 #define	ASM_DEFAULT_SPEC "-mppc64"
 #define	ASM_SPEC	 "%(asm_spec64) %(asm_spec_common)"
 #define	LINK_OS_LINUX_SPEC "%(link_os_linux_spec64)"
+#define	LINK_SECURE_PLT_SPEC ""
 #else
 #if DEFAULT_ARCH64_P
 #define	ASM_DEFAULT_SPEC "-mppc%{!m32:64}"
 #define	ASM_SPEC	 "%{m32:%(asm_spec32)}%{!m32:%(asm_spec64)} %(asm_spec_common)"
 #define	LINK_OS_LINUX_SPEC "%{m32:%(link_os_linux_spec32)}%{!m32:%(link_os_linux_spec64)}"
+#define	LINK_SECURE_PLT_SPEC "%{m32: " LINK_SECURE_PLT_DEFAULT_SPEC "}"
 #else
 #define	ASM_DEFAULT_SPEC "-mppc%{m64:64}"
 #define	ASM_SPEC	 "%{!m64:%(asm_spec32)}%{m64:%(asm_spec64)} %(asm_spec_common)"
 #define	LINK_OS_LINUX_SPEC "%{!m64:%(link_os_linux_spec32)}%{m64:%(link_os_linux_spec64)}"
+#define	LINK_SECURE_PLT_SPEC "%{!m64: " LINK_SECURE_PLT_DEFAULT_SPEC "}"
 #endif
 #endif
 
@@ -299,10 +303,14 @@ extern int dot_symbols;
 #define OPTION_GLIBC  (DEFAULT_LIBC == LIBC_GLIBC)
 #define OPTION_UCLIBC (DEFAULT_LIBC == LIBC_UCLIBC)
 #define OPTION_BIONIC (DEFAULT_LIBC == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (DEFAULT_LIBC == LIBC_MUSL)
 #else
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#undef OPTION_MUSL
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 #endif
 
 /* Determine what functions are present at the runtime;
@@ -363,19 +371,32 @@ extern int dot_symbols;
 #else
 #define GLIBC_DYNAMIC_LINKER64 "%{mabi=elfv2:/lib64/ld64.so.2;:/lib64/ld64.so.1}"
 #endif
+
+#define MUSL_DYNAMIC_LINKER32 \
+  "/lib/ld-musl-powerpc" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
+#define MUSL_DYNAMIC_LINKER64 \
+  "/lib/ld-musl-powerpc64" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
+
 #define UCLIBC_DYNAMIC_LINKER32 "/lib/ld-uClibc.so.0"
 #define UCLIBC_DYNAMIC_LINKER64 "/lib/ld64-uClibc.so.0"
 #if DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{mmusl:" M ";:" U "}}"
 #elif DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{muclibc:" U ";:%{mmusl:" M ";:" G "}}"
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{muclibc:" U ";:" M "}}"
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif
 #define GNU_USER_DYNAMIC_LINKER32 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, \
+			 MUSL_DYNAMIC_LINKER32)
 #define GNU_USER_DYNAMIC_LINKER64 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, \
+			 MUSL_DYNAMIC_LINKER64)
 
 #undef  DEFAULT_ASM_ENDIAN
 #if (TARGET_DEFAULT & MASK_LITTLE_ENDIAN)
diff --git a/gcc/config/rs6000/secureplt.h b/gcc/config/rs6000/secureplt.h
index b463463..77edf2a 100644
--- a/gcc/config/rs6000/secureplt.h
+++ b/gcc/config/rs6000/secureplt.h
@@ -18,3 +18,4 @@ along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
 #define CC1_SECURE_PLT_DEFAULT_SPEC "-msecure-plt"
+#define LINK_SECURE_PLT_DEFAULT_SPEC "--secure-plt"
diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
index c6c31dc..28af26d 100644
--- a/gcc/config/rs6000/sysv4.h
+++ b/gcc/config/rs6000/sysv4.h
@@ -538,6 +538,10 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
 #define CC1_SECURE_PLT_DEFAULT_SPEC ""
 #endif
 
+#ifndef LINK_SECURE_PLT_DEFAULT_SPEC
+#define LINK_SECURE_PLT_DEFAULT_SPEC ""
+#endif
+
 /* Pass -G xxx to the compiler.  */
 #undef CC1_SPEC
 #define	CC1_SPEC "%{G*} %(cc1_cpu)" \
@@ -567,6 +571,7 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
                : %(link_start_default)     }"
 
 #define LINK_START_DEFAULT_SPEC ""
+#define LINK_SECURE_PLT_SPEC LINK_SECURE_PLT_DEFAULT_SPEC
 
 #undef	LINK_SPEC
 #define	LINK_SPEC "\
@@ -574,6 +579,7 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
 %{R*} \
 %(link_shlib) \
 %{!T*: %(link_start) } \
+%{!static: %{!mbss-plt: %(link_secure_plt)}} \
 %(link_os)"
 
 /* Shared libraries are not default.  */
@@ -757,17 +763,27 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
 
 #define LINK_START_LINUX_SPEC ""
 
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","")
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
 #define UCLIBC_DYNAMIC_LINKER "/lib/ld-uClibc.so.0"
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-powerpc" MUSL_DYNAMIC_LINKER_E "%{msoft-float:-sf}.so.1"
 #if DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{mmusl:" M ";:" U "}}"
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{mglibc:" G ";:%{muclibc:" U ";:" M "}}"
 #elif !defined (DEFAULT_LIBC) || DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) \
+  "%{muclibc:" U ";:%{mmusl:" M ";:" G "}}"
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif
 #define GNU_USER_DYNAMIC_LINKER \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER, \
+			 MUSL_DYNAMIC_LINKER)
 
 #define LINK_OS_LINUX_SPEC "-m elf32ppclinux %{!shared: %{!static: \
   %{rdynamic:-export-dynamic} \
@@ -889,6 +905,7 @@ ncrtn.o%s"
   { "link_os_openbsd",		LINK_OS_OPENBSD_SPEC },			\
   { "link_os_default",		LINK_OS_DEFAULT_SPEC },			\
   { "cc1_secure_plt_default",	CC1_SECURE_PLT_DEFAULT_SPEC },		\
+  { "link_secure_plt",		LINK_SECURE_PLT_SPEC },			\
   { "cpp_os_ads",		CPP_OS_ADS_SPEC },			\
   { "cpp_os_yellowknife",	CPP_OS_YELLOWKNIFE_SPEC },		\
   { "cpp_os_mvme",		CPP_OS_MVME_SPEC },			\
@@ -943,3 +960,73 @@ ncrtn.o%s"
 /* This target uses the sysv4.opt file.  */
 #define TARGET_USES_SYSV4_OPT 1
 
+/* Include order changes for musl, same as in generic linux.h.  */
+#if DEFAULT_LIBC == LIBC_MUSL
+#define INCLUDE_DEFAULTS_MUSL_GPP			\
+    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },		\
+    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1,		\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 1 },		\
+    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1,	\
+      GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },
+
+#ifdef LOCAL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_LOCAL			\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },		\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_LOCAL
+#endif
+
+#ifdef PREFIX_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_PREFIX
+#endif
+
+#ifdef CROSS_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_CROSS			\
+    { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#ifdef TOOL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_TOOL			\
+    { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_TOOL
+#endif
+
+#ifdef NATIVE_SYSTEM_HEADER_DIR
+#define INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 },	\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_NATIVE
+#endif
+
+#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
+# undef INCLUDE_DEFAULTS_MUSL_LOCAL
+# define INCLUDE_DEFAULTS_MUSL_LOCAL
+# undef INCLUDE_DEFAULTS_MUSL_NATIVE
+# define INCLUDE_DEFAULTS_MUSL_NATIVE
+#else
+# undef INCLUDE_DEFAULTS_MUSL_CROSS
+# define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#undef INCLUDE_DEFAULTS
+#define INCLUDE_DEFAULTS				\
+  {							\
+    INCLUDE_DEFAULTS_MUSL_GPP				\
+    INCLUDE_DEFAULTS_MUSL_LOCAL				\
+    INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    INCLUDE_DEFAULTS_MUSL_CROSS				\
+    INCLUDE_DEFAULTS_MUSL_TOOL				\
+    INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 },		\
+    { 0, 0, 0, 0, 0, 0 }				\
+  }
+#endif
diff --git a/gcc/config/rs6000/sysv4le.h b/gcc/config/rs6000/sysv4le.h
index 66ee7ca..f00e8b0 100644
--- a/gcc/config/rs6000/sysv4le.h
+++ b/gcc/config/rs6000/sysv4le.h
@@ -31,3 +31,5 @@
 /* Little-endian PowerPC64 Linux uses the ELF v2 ABI by default.  */
 #define LINUX64_DEFAULT_ABI_ELFv2
 
+#undef MUSL_DYNAMIC_LINKER_E
+#define MUSL_DYNAMIC_LINKER_E ENDIAN_SELECT("","le","le")
diff --git a/gcc/config/sh/linux.h b/gcc/config/sh/linux.h
index 0f5d614..61cf777 100644
--- a/gcc/config/sh/linux.h
+++ b/gcc/config/sh/linux.h
@@ -43,6 +43,27 @@ along with GCC; see the file COPYING3.  If not see
 
 #define TARGET_ASM_FILE_END file_end_indicate_exec_stack
 
+#if TARGET_ENDIAN_DEFAULT == MASK_LITTLE_ENDIAN
+#define MUSL_DYNAMIC_LINKER_E "%{mb:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{!ml:eb}"
+#endif
+
+#if TARGET_CPU_DEFAULT & (MASK_HARD_SH2A_DOUBLE | MASK_SH4)
+/* "-nofpu" if any nofpu option is specified.  */
+#define MUSL_DYNAMIC_LINKER_FP \
+  "%{m1|m2|m2a-nofpu|m3|m4-nofpu|m4-100-nofpu|m4-200-nofpu|m4-300-nofpu|" \
+  "m4-340|m4-400|m4-500|m4al:-nofpu}"
+#else
+/* "-nofpu" if none of the hard fpu options are specified.  */
+#define MUSL_DYNAMIC_LINKER_FP "%{m2a|m4|m4-100|m4-200|m4-300|m4a:;:-nofpu}"
+#endif
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-sh" MUSL_DYNAMIC_LINKER_E MUSL_DYNAMIC_LINKER_FP \
+  "%{mfdpic:-fdpic}.so.1"
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
 
 #undef SUBTARGET_LINK_EMUL_SUFFIX
diff --git a/gcc/configure b/gcc/configure
index 3c92795..84d93fd 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -27802,6 +27802,9 @@ if test "${gcc_cv_libc_provides_ssp+set}" = set; then :
 else
   gcc_cv_libc_provides_ssp=no
     case "$target" in
+       *-*-musl*)
+	 # All versions of musl provide stack protector
+	 gcc_cv_libc_provides_ssp=yes;;
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)
       # glibc 2.4 and later provides __stack_chk_fail and
       # either __stack_chk_guard, or TLS access to stack guard canary.
@@ -27834,6 +27837,7 @@ fi
 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now
 	 # simply assert that glibc does provide this, which is true for all
 	 # realistically usable GNU/Hurd configurations.
+	 # All supported versions of musl provide it as well
 	 gcc_cv_libc_provides_ssp=yes;;
        *-*-darwin* | *-*-freebsd*)
 	 ac_fn_c_check_func "$LINENO" "__stack_chk_fail" "ac_cv_func___stack_chk_fail"
@@ -27930,6 +27934,9 @@ case "$target" in
       gcc_cv_target_dl_iterate_phdr=no
     fi
     ;;
+  *-linux-musl*)
+    gcc_cv_target_dl_iterate_phdr=yes
+    ;;
 esac
 
 if test x$gcc_cv_target_dl_iterate_phdr = xyes; then
diff --git a/gcc/configure.ac b/gcc/configure.ac
index d414081..134e561 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5282,6 +5282,9 @@ AC_CACHE_CHECK(__stack_chk_fail in target C library,
       gcc_cv_libc_provides_ssp,
       [gcc_cv_libc_provides_ssp=no
     case "$target" in
+       *-*-musl*)
+	 # All versions of musl provide stack protector
+	 gcc_cv_libc_provides_ssp=yes;;
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)
       # glibc 2.4 and later provides __stack_chk_fail and
       # either __stack_chk_guard, or TLS access to stack guard canary.
@@ -5308,6 +5311,7 @@ AC_CACHE_CHECK(__stack_chk_fail in target C library,
 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now
 	 # simply assert that glibc does provide this, which is true for all
 	 # realistically usable GNU/Hurd configurations.
+	 # All supported versions of musl provide it as well
 	 gcc_cv_libc_provides_ssp=yes;;
        *-*-darwin* | *-*-freebsd*)
 	 AC_CHECK_FUNC(__stack_chk_fail,[gcc_cv_libc_provides_ssp=yes],
@@ -5381,6 +5385,9 @@ case "$target" in
       gcc_cv_target_dl_iterate_phdr=no
     fi
     ;;
+  *-linux-musl*)
+    gcc_cv_target_dl_iterate_phdr=yes
+    ;;
 esac
 GCC_TARGET_TEMPLATE([TARGET_DL_ITERATE_PHDR])
 if test x$gcc_cv_target_dl_iterate_phdr = xyes; then
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d3be589..27d698e 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -667,7 +667,7 @@ Objective-C and Objective-C++ Dialects}.
 -mcpu=@var{cpu}}
 
 @emph{GNU/Linux Options}
-@gccoptlist{-mglibc -muclibc -mbionic -mandroid @gol
+@gccoptlist{-mglibc -muclibc -mmusl -mbionic -mandroid @gol
 -tno-android-cc -tno-android-ld}
 
 @emph{H8/300 Options}
@@ -15325,13 +15325,19 @@ These @samp{-m} options are defined for GNU/Linux targets:
 @item -mglibc
 @opindex mglibc
 Use the GNU C library.  This is the default except
-on @samp{*-*-linux-*uclibc*} and @samp{*-*-linux-*android*} targets.
+on @samp{*-*-linux-*uclibc*}, @samp{*-*-linux-*musl*} and
+@samp{*-*-linux-*android*} targets.
 
 @item -muclibc
 @opindex muclibc
 Use uClibc C library.  This is the default on
 @samp{*-*-linux-*uclibc*} targets.
 
+@item -mmusl
+@opindex mmusl
+Use the musl C library.  This is the default on
+@samp{*-*-linux-*musl*} targets.
+
 @item -mbionic
 @opindex mbionic
 Use Bionic C library.  This is the default on
diff --git a/gcc/gcc.c b/gcc/gcc.c
index d956c36..5289b6e 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -729,7 +729,8 @@ proper position among the other output files.  */
 #ifndef LINK_SSP_SPEC
 #ifdef TARGET_LIBC_PROVIDES_SSP
 #define LINK_SSP_SPEC "%{fstack-protector|fstack-protector-all" \
-		       "|fstack-protector-strong|fstack-protector-explicit:}"
+		       "|fstack-protector-strong|fstack-protector-explicit" \
+		       ":-lssp_nonshared}"
 #else
 #define LINK_SSP_SPEC "%{fstack-protector|fstack-protector-all" \
 		       "|fstack-protector-strong|fstack-protector-explicit" \
diff --git a/libcilkrts/runtime/os-unix.c b/libcilkrts/runtime/os-unix.c
index cb582dd..e43d7d5 100644
--- a/libcilkrts/runtime/os-unix.c
+++ b/libcilkrts/runtime/os-unix.c
@@ -51,6 +51,7 @@
 #if defined __linux__
 #   include <sys/sysinfo.h>
 #   include <sys/syscall.h>
+#   include <sched.h>
 #elif defined __APPLE__
 #   include <sys/sysctl.h>
     // Uses sysconf(_SC_NPROCESSORS_ONLN) in verbose output
@@ -400,28 +401,19 @@ COMMON_SYSDEP void __cilkrts_sleep(void)
 
 COMMON_SYSDEP void __cilkrts_yield(void)
 {
-#if __APPLE__ || __FreeBSD__ || __VXWORKS__
-    // On MacOS, call sched_yield to yield quantum.  I'm not sure why we
-    // don't do this on Linux also.
-    sched_yield();
-#elif defined(__DragonFly__)
-    // On DragonFly BSD, call sched_yield to yield quantum.
-    sched_yield();
-#elif defined(__MIC__)
+#if defined(__MIC__)
     // On MIC, pthread_yield() really trashes things.  Arch's measurements
     // showed that calling _mm_delay_32() (or doing nothing) was a better
     // option.  Delaying 1024 clock cycles is a reasonable compromise between
     // giving up the processor and latency starting up when work becomes
     // available
     _mm_delay_32(1024);
-#elif defined(__ANDROID__) || (defined(__sun__) && defined(__svr4__))
-    // On Android and Solaris, call sched_yield to yield quantum.  I'm not
-    // sure why we don't do this on Linux also.
-    sched_yield();
-#else
-    // On Linux, call pthread_yield (which in turn will call sched_yield)
-    // to yield quantum.
+#elif defined(__sun__) && !defined(__svr4__)
+    // On old SunOS call pthread_yield to yield a quantum.
     pthread_yield();
+#else
+    // On other platforms call sched_yield to yield a quantum.
+    sched_yield();
 #endif
 }
 
diff --git a/libgcc/unwind-dw2-fde-dip.c b/libgcc/unwind-dw2-fde-dip.c
index e1e566b..137dced 100644
--- a/libgcc/unwind-dw2-fde-dip.c
+++ b/libgcc/unwind-dw2-fde-dip.c
@@ -59,6 +59,12 @@
 
 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
     && defined(TARGET_DL_ITERATE_PHDR) \
+    && defined(__linux__)
+# define USE_PT_GNU_EH_FRAME
+#endif
+
+#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
+    && defined(TARGET_DL_ITERATE_PHDR) \
     && (defined(__DragonFly__) || defined(__FreeBSD__))
 # define ElfW __ElfN
 # define USE_PT_GNU_EH_FRAME
diff --git a/libgfortran/acinclude.m4 b/libgfortran/acinclude.m4
index ba890f9..30b8b1a6 100644
--- a/libgfortran/acinclude.m4
+++ b/libgfortran/acinclude.m4
@@ -100,7 +100,7 @@ void foo (void);
 	      [Define to 1 if the target supports #pragma weak])
   fi
   case "$host" in
-    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* )
+    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | *-*-musl* )
       AC_DEFINE(GTHREAD_USE_WEAK, 0,
 		[Define to 0 if the target shouldn't use #pragma weak])
       ;;
diff --git a/libgfortran/configure b/libgfortran/configure
index bb3107b..8fcdbe1 100755
--- a/libgfortran/configure
+++ b/libgfortran/configure
@@ -26456,7 +26456,7 @@ $as_echo "#define SUPPORTS_WEAK 1" >>confdefs.h
 
   fi
   case "$host" in
-    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* )
+    *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | *-*-musl* )
 
 $as_echo "#define GTHREAD_USE_WEAK 0" >>confdefs.h
 
diff --git a/libitm/config/arm/hwcap.cc b/libitm/config/arm/hwcap.cc
index a1c2cfd..ea8f023 100644
--- a/libitm/config/arm/hwcap.cc
+++ b/libitm/config/arm/hwcap.cc
@@ -40,7 +40,7 @@ int GTM_hwcap HIDDEN = 0
 
 #ifdef __linux__
 #include <unistd.h>
-#include <sys/fcntl.h>
+#include <fcntl.h>
 #include <elf.h>
 
 static void __attribute__((constructor))
diff --git a/libitm/config/linux/x86/tls.h b/libitm/config/linux/x86/tls.h
index e731ab7..54ad8b6 100644
--- a/libitm/config/linux/x86/tls.h
+++ b/libitm/config/linux/x86/tls.h
@@ -25,16 +25,19 @@
 #ifndef LIBITM_X86_TLS_H
 #define LIBITM_X86_TLS_H 1
 
-#if defined(__GLIBC_PREREQ) && __GLIBC_PREREQ(2, 10)
+#if defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 10)
 /* Use slots in the TCB head rather than __thread lookups.
    GLIBC has reserved words 10 through 13 for TM.  */
 #define HAVE_ARCH_GTM_THREAD 1
 #define HAVE_ARCH_GTM_THREAD_DISP 1
 #endif
+#endif
 
 #include "config/generic/tls.h"
 
-#if defined(__GLIBC_PREREQ) && __GLIBC_PREREQ(2, 10)
+#if defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 10)
 namespace GTM HIDDEN {
 
 #ifdef __x86_64__
@@ -101,5 +104,6 @@ static inline void set_abi_disp(struct abi_dispatch *x)
 
 } // namespace GTM
 #endif /* >= GLIBC 2.10 */
+#endif
 
 #endif // LIBITM_X86_TLS_H
diff --git a/libstdc++-v3/config/os/generic/os_defines.h b/libstdc++-v3/config/os/generic/os_defines.h
index 45bf52a..103ec0e 100644
--- a/libstdc++-v3/config/os/generic/os_defines.h
+++ b/libstdc++-v3/config/os/generic/os_defines.h
@@ -33,4 +33,9 @@
 // System-specific #define, typedefs, corrections, etc, go here.  This
 // file will come before all others.
 
+// Disable the weak reference logic in gthr.h for os/generic because it
+// is broken on every platform unless there is implementation specific
+// workaround in gthr-posix.h and at link-time for static linking.
+#define _GLIBCXX_GTHREAD_USE_WEAK 0
+
 #endif
diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
index 640199c..106134e 100644
--- a/libstdc++-v3/configure.host
+++ b/libstdc++-v3/configure.host
@@ -273,6 +273,9 @@ case "${host_os}" in
   freebsd*)
     os_include_dir="os/bsd/freebsd"
     ;;
+  linux-musl*)
+    os_include_dir="os/generic"
+    ;;
   gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
     if [ "$uclibc" = "yes" ]; then
       os_include_dir="os/uclibc"

[-- Attachment #4: gcc-6.1.0.diff --]
[-- Type: text/x-diff, Size: 7244 bytes --]

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 3d044e8..82523e1 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -40269,10 +40269,10 @@ ix86_expand_builtin (tree exp, rtx target, rtx subtarget,
     {
     case IX86_BUILTIN_CPU_INIT:
       {
-	/* Make it call __cpu_indicator_init in libgcc. */
+	/* Make it call __cpu_indicator_init_local in libgcc.a. */
 	tree call_expr, fndecl, type;
         type = build_function_type_list (integer_type_node, NULL_TREE); 
-	fndecl = build_fn_decl ("__cpu_indicator_init", type);
+	fndecl = build_fn_decl ("__cpu_indicator_init_local", type);
 	call_expr = build_call_expr (fndecl, 0); 
 	return expand_expr (call_expr, target, mode, EXPAND_NORMAL);
       }
diff --git a/gcc/config/i386/pmm_malloc.h b/gcc/config/i386/pmm_malloc.h
index a1f98d3..4f6b2dc 100644
--- a/gcc/config/i386/pmm_malloc.h
+++ b/gcc/config/i386/pmm_malloc.h
@@ -27,12 +27,13 @@
 #include <stdlib.h>
 
 /* We can't depend on <stdlib.h> since the prototype of posix_memalign
-   may not be visible.  */
+   may not be visible and we can't pollute the namespace either.  */
 #ifndef __cplusplus
-extern int posix_memalign (void **, size_t, size_t);
+extern int _mm_posix_memalign (void **, size_t, size_t)
 #else
-extern "C" int posix_memalign (void **, size_t, size_t) throw ();
+extern "C" int _mm_posix_memalign (void **, size_t, size_t) throw ()
 #endif
+__asm__("posix_memalign");
 
 static __inline void *
 _mm_malloc (size_t size, size_t alignment)
@@ -42,7 +43,7 @@ _mm_malloc (size_t size, size_t alignment)
     return malloc (size);
   if (alignment == 2 || (sizeof (void *) == 8 && alignment == 4))
     alignment = sizeof (void *);
-  if (posix_memalign (&ptr, alignment, size) == 0)
+  if (_mm_posix_memalign (&ptr, alignment, size) == 0)
     return ptr;
   else
     return NULL;
diff --git a/gcc/config/linux.c b/gcc/config/linux.c
index 250296b..16c3768 100644
--- a/gcc/config/linux.c
+++ b/gcc/config/linux.c
@@ -26,7 +26,7 @@ along with GCC; see the file COPYING3.  If not see
 bool
 linux_libc_has_function (enum function_class fn_class)
 {
-  if (OPTION_GLIBC)
+  if (OPTION_GLIBC || OPTION_MUSL)
     return true;
   if (OPTION_BIONIC)
     if (fn_class == function_c94
diff --git a/gcc/configure b/gcc/configure
index 1c6e340..7e8b5d6 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -29390,6 +29390,33 @@ fi
 $as_echo "$gcc_cv_no_pie" >&6; }
 if test "$gcc_cv_no_pie" = "yes"; then
   NO_PIE_FLAG="-no-pie"
+else
+  # Check if -nopie works.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -nopie option" >&5
+$as_echo_n "checking for -nopie option... " >&6; }
+if test "${gcc_cv_nopie+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  saved_LDFLAGS="$LDFLAGS"
+     LDFLAGS="$LDFLAGS -nopie"
+     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int main(void) {return 0;}
+_ACEOF
+if ac_fn_cxx_try_link "$LINENO"; then :
+  gcc_cv_nopie=yes
+else
+  gcc_cv_nopie=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+     LDFLAGS="$saved_LDFLAGS"
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_nopie" >&5
+$as_echo "$gcc_cv_nopie" >&6; }
+  if test "$gcc_cv_nopie" = "yes"; then
+    NO_PIE_FLAG="-nopie"
+  fi
 fi
 
 
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 6c1dcd9..0ca7647 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -6098,6 +6098,19 @@ AC_CACHE_CHECK([for -no-pie option],
    LDFLAGS="$saved_LDFLAGS"])
 if test "$gcc_cv_no_pie" = "yes"; then
   NO_PIE_FLAG="-no-pie"
+else
+  # Check if -nopie works.
+  AC_CACHE_CHECK([for -nopie option],
+    [gcc_cv_nopie],
+    [saved_LDFLAGS="$LDFLAGS"
+     LDFLAGS="$LDFLAGS -nopie"
+     AC_LINK_IFELSE([int main(void) {return 0;}],
+       [gcc_cv_nopie=yes],
+       [gcc_cv_nopie=no])
+     LDFLAGS="$saved_LDFLAGS"])
+  if test "$gcc_cv_nopie" = "yes"; then
+    NO_PIE_FLAG="-nopie"
+  fi
 fi
 AC_SUBST([NO_PIE_FLAG])
 
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 1af5920..0208d61 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -860,7 +860,8 @@ proper position among the other output files.  */
 #ifndef LINK_SSP_SPEC
 #ifdef TARGET_LIBC_PROVIDES_SSP
 #define LINK_SSP_SPEC "%{fstack-protector|fstack-protector-all" \
-		       "|fstack-protector-strong|fstack-protector-explicit:}"
+		       "|fstack-protector-strong|fstack-protector-explicit" \
+		       ":-lssp_nonshared}"
 #else
 #define LINK_SSP_SPEC "%{fstack-protector|fstack-protector-all" \
 		       "|fstack-protector-strong|fstack-protector-explicit" \
diff --git a/libcilkrts/runtime/os-unix.c b/libcilkrts/runtime/os-unix.c
index cb582dd..e43d7d5 100644
--- a/libcilkrts/runtime/os-unix.c
+++ b/libcilkrts/runtime/os-unix.c
@@ -51,6 +51,7 @@
 #if defined __linux__
 #   include <sys/sysinfo.h>
 #   include <sys/syscall.h>
+#   include <sched.h>
 #elif defined __APPLE__
 #   include <sys/sysctl.h>
     // Uses sysconf(_SC_NPROCESSORS_ONLN) in verbose output
@@ -400,28 +401,19 @@ COMMON_SYSDEP void __cilkrts_sleep(void)
 
 COMMON_SYSDEP void __cilkrts_yield(void)
 {
-#if __APPLE__ || __FreeBSD__ || __VXWORKS__
-    // On MacOS, call sched_yield to yield quantum.  I'm not sure why we
-    // don't do this on Linux also.
-    sched_yield();
-#elif defined(__DragonFly__)
-    // On DragonFly BSD, call sched_yield to yield quantum.
-    sched_yield();
-#elif defined(__MIC__)
+#if defined(__MIC__)
     // On MIC, pthread_yield() really trashes things.  Arch's measurements
     // showed that calling _mm_delay_32() (or doing nothing) was a better
     // option.  Delaying 1024 clock cycles is a reasonable compromise between
     // giving up the processor and latency starting up when work becomes
     // available
     _mm_delay_32(1024);
-#elif defined(__ANDROID__) || (defined(__sun__) && defined(__svr4__))
-    // On Android and Solaris, call sched_yield to yield quantum.  I'm not
-    // sure why we don't do this on Linux also.
-    sched_yield();
-#else
-    // On Linux, call pthread_yield (which in turn will call sched_yield)
-    // to yield quantum.
+#elif defined(__sun__) && !defined(__svr4__)
+    // On old SunOS call pthread_yield to yield a quantum.
     pthread_yield();
+#else
+    // On other platforms call sched_yield to yield a quantum.
+    sched_yield();
 #endif
 }
 
diff --git a/libgcc/config/i386/cpuinfo.c b/libgcc/config/i386/cpuinfo.c
index 8c2248d..6c82f15 100644
--- a/libgcc/config/i386/cpuinfo.c
+++ b/libgcc/config/i386/cpuinfo.c
@@ -485,7 +485,7 @@ __cpu_indicator_init (void)
   return 0;
 }
 
-#if defined SHARED && defined USE_ELF_SYMVER
-__asm__ (".symver __cpu_indicator_init, __cpu_indicator_init@GCC_4.8.0");
-__asm__ (".symver __cpu_model, __cpu_model@GCC_4.8.0");
+#ifndef SHARED
+int __cpu_indicator_init_local (void)
+  __attribute__ ((weak, alias ("__cpu_indicator_init")));
 #endif
diff --git a/libgcc/config/i386/t-linux b/libgcc/config/i386/t-linux
index 11bb46e..4f47f7b 100644
--- a/libgcc/config/i386/t-linux
+++ b/libgcc/config/i386/t-linux
@@ -3,4 +3,4 @@
 # t-slibgcc-elf-ver and t-linux
 SHLIB_MAPFILES = libgcc-std.ver $(srcdir)/config/i386/libgcc-glibc.ver
 
-HOST_LIBGCC2_CFLAGS += -mlong-double-80 -DUSE_ELF_SYMVER
+HOST_LIBGCC2_CFLAGS += -mlong-double-80

Re: musl-cross-make / litecross improvements

[Patrick Oppenlander]

On 07/05/16 06:49, Szabolcs Nagy wrote:
> i think the powerpc patches wont apply

There is one (very minor) change required in gcc/config/rs6000/sysv4.h.

The sh sibcall patch also required a very small change in 
gcc/config/sh/sh.md.

Other than that the rest applied.

         Patrick

patrick@gtr ~/src/patrick/musl-cross-make (git)-[master] % diff -ur 
patches/gcc-5.2.0 patches/gcc-5.3.0
diff -u -ur patches/gcc-5.2.0/0001-musl.diff 
patches/gcc-5.3.0/0001-musl.diff
--- patches/gcc-5.2.0/0001-musl.diff    2016-05-05 15:23:11.817513705 +1000
+++ patches/gcc-5.3.0/0001-musl.diff    2016-05-06 14:36:54.454162324 +1000
@@ -466,16 +466,16 @@

   /* Pass -G xxx to the compiler.  */
   #undef CC1_SPEC
-@@ -586,7 +589,8 @@ ENDIAN_SELECT(" -mbig", " -mlittle", 
DEFAULT_ASM_ENDIAN)
+@@ -574,7 +577,8 @@
+ %{R*} \
+ %(link_shlib) \
+ %{!T*: %(link_start) } \
+-%(link_os)"
++%(link_os) \
++"%{!mbss-plt: %{!msecure-plt: %(link_secure_plt_default)}}"

- /* Override the default target of the linker.  */
- #define    LINK_TARGET_SPEC \
--  ENDIAN_SELECT("", " --oformat elf32-powerpcle", "")
-+  ENDIAN_SELECT("", " --oformat elf32-powerpcle", "") \
-+  "%{!mbss-plt: %{!msecure-plt: %(link_secure_plt_default)}}"
-
- /* Any specific OS flags.  */
- #define LINK_OS_SPEC "\
+ /* Shared libraries are not default.  */
+ #define LINK_SHLIB_SPEC "\
  @@ -762,17 +766,23 @@ ENDIAN_SELECT(" -mbig", " -mlittle", 
DEFAULT_ASM_ENDIAN)

   #define LINK_START_LINUX_SPEC ""
diff -u -ur patches/gcc-5.2.0/0008-shsibcall.diff 
patches/gcc-5.3.0/0008-shsibcall.diff
--- patches/gcc-5.2.0/0008-shsibcall.diff    2016-05-05 
15:23:11.817513705 +1000
+++ patches/gcc-5.3.0/0008-shsibcall.diff    2016-05-06 
15:18:09.679230171 +1000
@@ -4,7 +4,7 @@
          (call (mem:SI (match_operand:SI 1 "symbol_ref_operand" ""))
                (match_operand 2 "" "")))
      (use (reg:SI FPSCR_MODES_REG))
--   (clobber (match_scratch:SI 3 "=k"))
+-   (clobber (match_scratch:SI 3 "=&k"))
  +   (clobber (reg:SI R1_REG))
      (return)]
     "TARGET_SH2 && !TARGET_FDPIC"