[PATCH] Remove possibly unused lines from Makefile

[PATCH] Remove possibly unused lines from Makefile

[Nicholas Wilson]

Hi,

There are a couple of lines I've had to hack out of the Makefile to get Wasm to build. In WebAssembly, we can't use crti.s/crtn.s, because the compiler doesn't support raw assembly chunks like that.

That should be OK, since there are default empty files in "crt/{crti,crtn}.c". Those empty files are currently unused, as all archs provide the assembly versions. For WebAssembly, I'm happy for those empty C files to be used.

There's some clever stuff at the top of the Makefile to construct BASE_SRCS and ARCH_SRCS, and it works fine for WebAssembly: we just compile the dummy .c files if the .s files aren't provided by the arch.

The problem is further down the Makefile, where an apparently unnecessary dependency is placed on the assembly files. I can't work out why these two lines are there, and they need to be removed in one way or another for the Wasm build to succeed. Getting rid of them doesn't seem to have any negative consequences for the standard x86 build.

Patch below.

Thanks,
Nick

============
diff --git a/Makefile b/Makefile
index d2e89979..308ddaae 100644
--- a/Makefile
+++ b/Makefile
@@ -113,10 +113,6 @@ obj/crt/rcrt1.o: $(srcdir)/ldso/dlstart.c
 
 obj/crt/Scrt1.o obj/crt/rcrt1.o: CFLAGS_ALL += -fPIC
 
-obj/crt/$(ARCH)/crti.o: $(srcdir)/crt/$(ARCH)/crti.s
-
-obj/crt/$(ARCH)/crtn.o: $(srcdir)/crt/$(ARCH)/crtn.s
-
 OPTIMIZE_SRCS = $(wildcard $(OPTIMIZE_GLOBS:%=$(srcdir)/src/%))
 $(OPTIMIZE_SRCS:$(srcdir)/%.c=obj/%.o) $(OPTIMIZE_SRCS:$(srcdir)/%.c=obj/%.lo): CFLAGS += -O3
 

Re: [PATCH] Remove possibly unused lines from Makefile

[Rich Felker]

On Thu, Dec 07, 2017 at 03:55:52PM +0000, Nicholas Wilson wrote:
> Hi,
> 
> There are a couple of lines I've had to hack out of the Makefile to
> get Wasm to build. In WebAssembly, we can't use crti.s/crtn.s,
> because the compiler doesn't support raw assembly chunks like that.
> 
> That should be OK, since there are default empty files in
> "crt/{crti,crtn}.c". Those empty files are currently unused, as all
> archs provide the assembly versions. For WebAssembly, I'm happy for
> those empty C files to be used.
> 
> There's some clever stuff at the top of the Makefile to construct
> BASE_SRCS and ARCH_SRCS, and it works fine for WebAssembly: we just
> compile the dummy .c files if the .s files aren't provided by the
> arch.
> 
> The problem is further down the Makefile, where an apparently
> unnecessary dependency is placed on the assembly files. I can't work
> out why these two lines are there, and they need to be removed in
> one way or another for the Wasm build to succeed. Getting rid of
> them doesn't seem to have any negative consequences for the standard
> x86 build.
> 
> Patch below.
> 
> Thanks,
> Nick
> 
> ============
> diff --git a/Makefile b/Makefile
> index d2e89979..308ddaae 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -113,10 +113,6 @@ obj/crt/rcrt1.o: $(srcdir)/ldso/dlstart.c
>  
>  obj/crt/Scrt1.o obj/crt/rcrt1.o: CFLAGS_ALL += -fPIC
>  
> -obj/crt/$(ARCH)/crti.o: $(srcdir)/crt/$(ARCH)/crti.s
> -
> -obj/crt/$(ARCH)/crtn.o: $(srcdir)/crt/$(ARCH)/crtn.s
> -
>  OPTIMIZE_SRCS = $(wildcard $(OPTIMIZE_GLOBS:%=$(srcdir)/src/%))
>  $(OPTIMIZE_SRCS:$(srcdir)/%.c=obj/%.o) $(OPTIMIZE_SRCS:$(srcdir)/%.c=obj/%.lo): CFLAGS += -O3
>  

Looks good. I'm committing this with a message explaining the
historical reasons these lines appeared and why it makes sense to
remove them.

Rich