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* RE: PE target support in configure & Makefile
@ 2015-11-05  2:18 writeonce
  0 siblings, 0 replies; 3+ messages in thread
From: writeonce @ 2015-11-05  2:18 UTC (permalink / raw)
  To: musl

On 11/04/2015 08:52 PM, Rich Felker wrote:
> On Wed, Nov 04, 2015 at 05:39:55PM -0700, writeonce@midipix.org wrote:
>> Greetings,
>>
>> As many of you know, musl has been ported to winnt (and has an already
>> working bash/dash, core shell utilities, and a native toolchain) without
>> applying any patches to the upstream source tree.[1] Thus far, however,
>> we have been building musl using a deviant script that we now hope to
>> retire.
> 
> Thanks for the report/info/patch. Since build system overhaul is
> already on the roadmap for this release cycle, I'm including some
> general comments on things that could be changed as part of this reply
> where they're related to things you want to change.
> 
>> As musl's build system is currently being revisited, I would like
>> propose (with the attached patch as a reference) the addition of the
>> following features:
>>
>> 1. add rules for $(ARCH)/%.c: C-language arch-specific files.
> 
> After discussing this briefly on IRC I think this is a change that
> would be welcome in general as part of the build overhaul in this
> release cycle. There are actually a number of reasons we might want to
> transition from asm source files to C files with inline asm for _most_
> (not all; see below) of the arch-specific asm:
> 
> - Enabling LTO inlining.
> 
> - Ability to generate code for multiple calling conventions/ABIs from
>    the same sources.
> 
> - Eliminating the issue of missing CFI in asm source files.
> 
> - Eliminating most ugly non-code directives in asm source files.
> 
> Of course some functions cannot be written in C at all: mainly vfork,
> setjmp, the tlsdesc functions, and anything else that returns twice or
> has a nonstandard calling convention.
> 
> No decision needs to be made at this time however; enabling arch
> replacements via C files in addition to just asm files does not
> require that we change anything.
> 
>> 2. --arch=ARCH: alternate arch-specific source files.
>> at the present, ARCH is derived from TARGET and has no corresponding
>> configure switch. Adding --arch support would allow setting nt32 and
>> nt64 as the arch directories for winnt's i686 and x86_64 targets,
>> respectively.
> 
> I think this should be derived from target (by default, obtained from
> $CC -dumpmachine). Adding yet another option that can be set
> inconsistently and which has not-widely-known interaction with the
> standard options seems like a bad idea.
> 

That works too, of course, but would require special-casing the PE
targets since -dumpmachine returns x86_64-nt64-midipix
(i686-nt32-midipix), whereas the arch-specific files are in nt64 (nt32).

>> 3. PE target detection, shared library linker flags.
>> at the present, musl's configure script assumes ELF targets as well as
>> its own loader routine (_dlstart). PE target support could be added with
>> only a minimal effort if we a) detect PE targets using the compiler, and
>> b) set PE/ELF-specific linker flags accordingly.
> 
> See my comments below interleaved with the patch.
> 
>> diff -u musl-1.1.12/configure musl-1.1.12.alt/configure
>> --- musl-1.1.12/configure	2015-10-19 19:12:57.000000000 -0400
>> +++ musl-1.1.12.alt/configure	2015-11-04 18:08:50.676855247 -0500
>> @@ -22,6 +22,7 @@
>>   System types:
>>     --target=TARGET         configure to run on target TARGET [detected]
>>     --host=HOST             same as --target
>> +  --arch=ARCH             use alternate ARCH-specific source files for TARGET
>>   
>>   Optional features:
>>     --enable-optimize=...   optimize listed components for speed over size [auto]
>> @@ -166,6 +167,7 @@
>>   --enable-gcc-wrapper|--enable-gcc-wrapper=yes) wrapper=yes ; gcc_wrapper=yes ;;
>>   --disable-gcc-wrapper|--enable-gcc-wrapper=no) wrapper=no ;;
>>   --enable-*|--disable-*|--with-*|--without-*|--*dir=*|--build=*) ;;
>> +--arch=*) ARCH=${arg#*=} ;;
>>   --host=*|--target=*) target=${arg#*=} ;;
>>   -* ) echo "$0: unknown option $arg" ;;
>>   CC=*) CC=${arg#*=} ;;
>> @@ -280,7 +282,7 @@
>>   #
>>   # Convert to just ARCH
>>   #
>> -case "$target" in
>> +test -z "$ARCH" && case "$target" in
>>   # Catch these early to simplify matching for 32-bit archs
>>   mips64*|powerpc64*) fail "$0: unsupported target \"$target\"" ;;
>>   arm*) ARCH=arm ;;
>> @@ -504,6 +506,10 @@
>>   CFLAGS_AUTO="${CFLAGS_AUTO# }"
>>   fi
>>   
>> +# detect PE targets
>> +test -z "$PE_TARGET" && "$CC" -dM -E - < /dev/null \
>> +	| grep __PE__ >/dev/null && PE_TARGET=yes
>> +
>>   # Some patched GCC builds have these defaults messed up...
>>   tryldflag LDFLAGS_AUTO -Wl,--hash-style=both
> 
> Why not just use the $ARCH names for midipix rather than probing the
> compiler for something you already know?
> 

Indeed. And if end up special-casing the targets for ARCH, then
PE_TARGET should probably be set as part of that same check.

>> @@ -513,7 +519,7 @@
>>   # runtime library; implementation error is also a possibility.
>>   tryldflag LDFLAGS_AUTO -Wl,--no-undefined
>>   
>> -test "$shared" = "no" || {
>> +test "$shared" = "no" || test "$PE_TARGET" = "yes" || {
>>   # Disable dynamic linking if ld is broken and can't do -Bsymbolic-functions
>>   LDFLAGS_DUMMY=
>>   tryldflag LDFLAGS_DUMMY -Wl,-Bsymbolic-functions || {
>> @@ -523,6 +529,19 @@
>>   }
>>   }
> 
> I think we can actually make -Bsymbolic-functions optional and just
> detect it. As an aside, we could support interposing malloc (a widely
> requested feature, though one that requires a lot of care to make
> safe) by using --dynamic-list-data and --dynamic-list FILE, where FILE
> contains a list of the malloc-related symbols, instead of
> -Bsymbolic-functions. Or we could just drop it alltogether and let
> visibility do the work for us instead.
> 
>> +# PE/ELF-specific LDFLAGS
>> +test "$shared" = "no" || {
>> +
>> +test "$PE_TARGET" = "yes" && "$CC" -dM -E - < /dev/null \
>> +	| grep __SIZEOF_POINTER__ | grep 4 >/dev/null && underscore='_'
>> +
>> +test "$PE_TARGET" = "yes" && \
>> +	LDFLAGS_IMG_FMT="-Wl,-e,${underscore}__libc_entry_point -Wl,--subsystem,windows"
>> +
>> +test "$PE_TARGET" = "yes" || \
>> +	LDFLAGS_IMG_FMT="-Wl,-e,_dlstart -Wl,-Bsymbolic-functions"
>> +}
> 
> Why not just arrange for the name to always be the same at the C
> source level by using one fewer underscore in the 32-bit version?
> Complex logic like this should be minimized at the configure level.

Indeed :-)

> 
> Rich
> 
> 




^ permalink raw reply	[flat|nested] 3+ messages in thread
* PE target support in configure & Makefile
@ 2015-11-05  0:39 writeonce
  2015-11-05  1:52 ` Rich Felker
  0 siblings, 1 reply; 3+ messages in thread
From: writeonce @ 2015-11-05  0:39 UTC (permalink / raw)
  To: musl

[-- Attachment #1: Type: text/plain, Size: 1200 bytes --]

Greetings,

As many of you know, musl has been ported to winnt (and has an already
working bash/dash, core shell utilities, and a native toolchain) without
applying any patches to the upstream source tree.[1] Thus far, however,
we have been building musl using a deviant script that we now hope to
retire.

As musl's build system is currently being revisited, I would like
propose (with the attached patch as a reference) the addition of the
following features:

1. add rules for $(ARCH)/%.c: C-language arch-specific files.

2. --arch=ARCH: alternate arch-specific source files.
at the present, ARCH is derived from TARGET and has no corresponding
configure switch. Adding --arch support would allow setting nt32 and
nt64 as the arch directories for winnt's i686 and x86_64 targets,
respectively.

3. PE target detection, shared library linker flags.
at the present, musl's configure script assumes ELF targets as well as
its own loader routine (_dlstart). PE target support could be added with
only a minimal effort if we a) detect PE targets using the compiler, and
b) set PE/ELF-specific linker flags accordingly.

Best regards,
z.g.

[1] git://midipix.org/mmglue


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: musl-pe-support.patch --]
[-- Type: text/x-diff; name="musl-pe-support.patch";, Size: 3435 bytes --]

diff -u musl-1.1.12/configure musl-1.1.12.alt/configure
--- musl-1.1.12/configure	2015-10-19 19:12:57.000000000 -0400
+++ musl-1.1.12.alt/configure	2015-11-04 18:08:50.676855247 -0500
@@ -22,6 +22,7 @@
 System types:
   --target=TARGET         configure to run on target TARGET [detected]
   --host=HOST             same as --target
+  --arch=ARCH             use alternate ARCH-specific source files for TARGET
 
 Optional features:
   --enable-optimize=...   optimize listed components for speed over size [auto]
@@ -166,6 +167,7 @@
 --enable-gcc-wrapper|--enable-gcc-wrapper=yes) wrapper=yes ; gcc_wrapper=yes ;;
 --disable-gcc-wrapper|--enable-gcc-wrapper=no) wrapper=no ;;
 --enable-*|--disable-*|--with-*|--without-*|--*dir=*|--build=*) ;;
+--arch=*) ARCH=${arg#*=} ;;
 --host=*|--target=*) target=${arg#*=} ;;
 -* ) echo "$0: unknown option $arg" ;;
 CC=*) CC=${arg#*=} ;;
@@ -280,7 +282,7 @@
 #
 # Convert to just ARCH
 #
-case "$target" in
+test -z "$ARCH" && case "$target" in
 # Catch these early to simplify matching for 32-bit archs
 mips64*|powerpc64*) fail "$0: unsupported target \"$target\"" ;;
 arm*) ARCH=arm ;;
@@ -504,6 +506,10 @@
 CFLAGS_AUTO="${CFLAGS_AUTO# }"
 fi
 
+# detect PE targets
+test -z "$PE_TARGET" && "$CC" -dM -E - < /dev/null \
+	| grep __PE__ >/dev/null && PE_TARGET=yes
+
 # Some patched GCC builds have these defaults messed up...
 tryldflag LDFLAGS_AUTO -Wl,--hash-style=both
 
@@ -513,7 +519,7 @@
 # runtime library; implementation error is also a possibility.
 tryldflag LDFLAGS_AUTO -Wl,--no-undefined
 
-test "$shared" = "no" || {
+test "$shared" = "no" || test "$PE_TARGET" = "yes" || {
 # Disable dynamic linking if ld is broken and can't do -Bsymbolic-functions
 LDFLAGS_DUMMY=
 tryldflag LDFLAGS_DUMMY -Wl,-Bsymbolic-functions || {
@@ -523,6 +529,19 @@
 }
 }
 
+# PE/ELF-specific LDFLAGS
+test "$shared" = "no" || {
+
+test "$PE_TARGET" = "yes" && "$CC" -dM -E - < /dev/null \
+	| grep __SIZEOF_POINTER__ | grep 4 >/dev/null && underscore='_'
+
+test "$PE_TARGET" = "yes" && \
+	LDFLAGS_IMG_FMT="-Wl,-e,${underscore}__libc_entry_point -Wl,--subsystem,windows"
+
+test "$PE_TARGET" = "yes" || \
+	LDFLAGS_IMG_FMT="-Wl,-e,_dlstart -Wl,-Bsymbolic-functions"
+}
+
 # Find compiler runtime library
 test -z "$LIBCC" && tryldflag LIBCC -lgcc && tryldflag LIBCC -lgcc_eh
 test -z "$LIBCC" && tryldflag LIBCC -lcompiler_rt
@@ -634,7 +653,7 @@
 CFLAGS_MEMOPS = $CFLAGS_MEMOPS
 CFLAGS_NOSSP = $CFLAGS_NOSSP
 CPPFLAGS = $CPPFLAGS
-LDFLAGS = $LDFLAGS_AUTO $LDFLAGS
+LDFLAGS = $LDFLAGS_AUTO $LDFLAGS $LDFLAGS_IMG_FMT
 CROSS_COMPILE = $CROSS_COMPILE
 LIBCC = $LIBCC
 OPTIMIZE_GLOBS = $OPTIMIZE_GLOBS
diff -u musl-1.1.12/Makefile musl-1.1.12.alt/Makefile
--- musl-1.1.12/Makefile	2015-10-19 19:12:57.000000000 -0400
+++ musl-1.1.12.alt/Makefile	2015-11-04 17:48:16.764815762 -0500
@@ -133,6 +133,9 @@
 %.o: $(ARCH)/%.s
 	$(AS_CMD) $(CFLAGS_ALL_STATIC)
 
+%.o: $(ARCH)/%.c $(GENH) $(IMPH)
+	$(CC) $(CFLAGS_ALL_STATIC) -c -o $@ $<
+
 %.o: %.c $(GENH) $(IMPH)
 	$(CC) $(CFLAGS_ALL_STATIC) -c -o $@ $<
 
@@ -142,12 +145,14 @@
 %.lo: $(ARCH)/%.s
 	$(AS_CMD) $(CFLAGS_ALL_SHARED)
 
+%.lo: $(ARCH)/%.c $(GENH) $(IMPH)
+	$(CC) $(CFLAGS_ALL_SHARED) -c -o $@ $<
+
 %.lo: %.c $(GENH) $(IMPH)
 	$(CC) $(CFLAGS_ALL_SHARED) -c -o $@ $<
 
 lib/libc.so: $(LOBJS)
 	$(CC) $(CFLAGS_ALL_SHARED) $(LDFLAGS) -nostdlib -shared \
-	-Wl,-e,_dlstart -Wl,-Bsymbolic-functions \
 	-o $@ $(LOBJS) $(LIBCC)
 
 lib/libc.a: $(OBJS)

^ permalink raw reply	[flat|nested] 3+ messages in thread
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2015-11-05  1:52 ` Rich Felker

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