[vlc-devel] [PATCH] contrib: pthreads: Fix building with llvm-mingw

[Steve Lhomme]

Le 21/02/2018 à 12:58, Martin Storsjö a écrit :
> This avoids doing things with dlltool that llvm-dlltool doesn't
> implement.
>
> I don't see the need of running a second pass with dlltool to
> produce an output def file and yet another pass to produce
> an import library out of it; just make the linker output the
> import library while linking the dll. (If the import library is
> to be used by MSVC, there is a point in generating it with dlltool
> instead of with ld though. Even then, there's no point in generating
> the def file using dlltool though, when it could just be generated by
> the linker.)
>
> Remove an inline declaration on a function that can't be inline-only
> (static inline).
>
> For non-static inline functions in C, the compiler can choose to
> use the inline function itself, or assume that a definition exists
> in a different translation unit. In this case, clang seems to
> not inline ptw32_cond_check_need_init and creates an undefined
> reference to the same function that should be defined in another
> translation unit (which doesn't exist).
>
> See https://www.greenend.org.uk/rjk/tech/inline.html for more details
> on this.
> ---
>   contrib/src/pthreads/implib.patch        | 33 ++++++++++++++++++++++++++++++++
>   contrib/src/pthreads/remove-inline.patch | 12 ++++++++++++
>   contrib/src/pthreads/rules.mak           |  2 ++
>   3 files changed, 47 insertions(+)
>   create mode 100644 contrib/src/pthreads/implib.patch
>   create mode 100644 contrib/src/pthreads/remove-inline.patch
>
> diff --git a/contrib/src/pthreads/implib.patch b/contrib/src/pthreads/implib.patch
> new file mode 100644
> index 0000000..01ad44b
> --- /dev/null
> +++ b/contrib/src/pthreads/implib.patch
> @@ -0,0 +1,33 @@
> +diff -urN pthreads-orig/GNUmakefile pthreads/GNUmakefile
> +--- pthreads-orig/GNUmakefile	2018-01-05 21:45:34.478551838 +0000
> ++++ pthreads/GNUmakefile	2018-01-05 21:51:37.918541470 +0000
> +@@ -523,25 +523,17 @@
> +
> +
> + $(GC_DLL) $(GCD_DLL): $(DLL_OBJS)
> +-	$(CC) $(OPT) -shared -o $(GC_DLL) $(DLL_OBJS) $(LFLAGS)
> +-	$(DLLTOOL) -z pthread.def $(DLL_OBJS)

In the original makefile it should be $(PTHREAD_DEF). They're not even 
consistent
> +-	$(DLLTOOL) -k --dllname $@ --output-lib $(GC_LIB) --def $(PTHREAD_DEF)
> ++	$(CC) $(OPT) -shared -o $(GC_DLL) -Wl,--out-implib,$(GC_LIB) $(DLL_OBJS) $(LFLAGS)
> +
> + $(GCE_DLL): $(DLL_OBJS)
> +-	$(CC) $(OPT) -mthreads -shared -o $(GCE_DLL) $(DLL_OBJS) $(LFLAGS)
> +-	$(DLLTOOL) -z pthread.def $(DLL_OBJS)
> +-	$(DLLTOOL) -k --dllname $@ --output-lib $(GCE_LIB) --def $(PTHREAD_DEF)
> ++	$(CC) $(OPT) -mthreads -shared -o $(GCE_DLL) -Wl,--out-implib,$(GCE_LIB) $(DLL_OBJS) $(LFLAGS)

You will end up generating a file like pthreadsGC2.def instead of 
pthreads.def. In the context of our contribs it doesn't matter. But if 
you plan on submitting it for backporting it may not be OK.

> +
> + $(GC_INLINED_STAMP) $(GCD_INLINED_STAMP): $(DLL_INLINED_OBJS)
> +-	$(CC) $(OPT) $(XOPT) -shared -o $(GC_DLL) $(DLL_INLINED_OBJS) $(LFLAGS)
> +-	$(DLLTOOL) -z pthread.def $(DLL_INLINED_OBJS)
> +-	$(DLLTOOL) -k --dllname $(GC_DLL) --output-lib $(GC_LIB) --def $(PTHREAD_DEF)
> ++	$(CC) $(OPT) $(XOPT) -shared -o $(GC_DLL) -Wl,--out-implib,$(GC_LIB) $(DLL_INLINED_OBJS) $(LFLAGS)
> + 	echo touched > $(GC_INLINED_STAMP)
> +
> + $(GCE_INLINED_STAMP) $(GCED_INLINED_STAMP): $(DLL_INLINED_OBJS)
> +-	$(CC) $(OPT) $(XOPT) -mthreads -shared -o $(GCE_DLL) $(DLL_INLINED_OBJS)  $(LFLAGS)
> +-	$(DLLTOOL) -z pthread.def $(DLL_INLINED_OBJS)
> +-	$(DLLTOOL) -k --dllname $(GCE_DLL) --output-lib $(GCE_LIB) --def $(PTHREAD_DEF)
> ++	$(CC) $(OPT) $(XOPT) -mthreads -shared -o $(GCE_DLL) -Wl,--out-implib,$(GCE_LIB) $(DLL_INLINED_OBJS)  $(LFLAGS)
> + 	echo touched > $(GCE_INLINED_STAMP)
> +
> + $(GC_STATIC_STAMP) $(GCD_STATIC_STAMP): $(DLL_INLINED_OBJS)
> diff --git a/contrib/src/pthreads/remove-inline.patch b/contrib/src/pthreads/remove-inline.patch
> new file mode 100644
> index 0000000..ef21bde
> --- /dev/null
> +++ b/contrib/src/pthreads/remove-inline.patch
> @@ -0,0 +1,12 @@
> +diff -urN pthreads-orig/ptw32_spinlock_check_need_init.c pthreads/ptw32_spinlock_check_need_init.c
> +--- pthreads-orig/ptw32_spinlock_check_need_init.c	2011-03-10 13:40:17.000000000 +0000
> ++++ pthreads/ptw32_spinlock_check_need_init.c	2018-01-06 07:22:18.399696662 +0000
> +@@ -38,7 +38,7 @@
> + #include "implement.h"
> +
> +
> +-INLINE int
> ++int
> + ptw32_spinlock_check_need_init (pthread_spinlock_t * lock)
> + {
> +   int result = 0;
> diff --git a/contrib/src/pthreads/rules.mak b/contrib/src/pthreads/rules.mak
> index 9c1a03db..8aeaf90 100644
> --- a/contrib/src/pthreads/rules.mak
> +++ b/contrib/src/pthreads/rules.mak
> @@ -19,6 +19,8 @@ pthreads: pthreads-w32-$(PTHREADS_W32_VERSION)-release.tar.gz .sum-pthreads
>   ifdef HAVE_WINSTORE
>   	$(APPLY) $(SRC)/pthreads/winrt.patch
>   endif
> +	$(APPLY) $(SRC)/pthreads/implib.patch
> +	$(APPLY) $(SRC)/pthreads/remove-inline.patch
>   	$(MOVE)
>   
>   ifdef HAVE_CROSS_COMPILE