use clang-cl's -Zc:dllexportInlines- for Skia (tdf#144598)

This is clang-cl's equivalent of -fvisibility-inlines-hidden,
and it seems to be also sort of the equivalent of MSVC's
-Zc:inline. So it saves build time and disk space.

As an additional effect, this disables emitting copies
of inlines functions in every .o file where the function
is called (even if inlined), which means that it hopefully
avoids the problem of SkOpts_avx.cpp generating a copy
of SkRect::round() which would include AVX code, and
the linker might select this as the instance of SkRect::round()
to keep, thus making SSE2 code call AVX code without checking
for AVX availability first.

Change-Id: I97541ae11d05f489894bc9233271eb21fd520f43
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/122335
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/external/skia/Library_skia.mk b/external/skia/Library_skia.mk
index 60b8a3caccb1..b1b4f874f44a 100644
--- a/external/skia/Library_skia.mk
+++ b/external/skia/Library_skia.mk
@@ -59,6 +59,17 @@ $(eval $(call gb_Library_use_system_win32_libs,skia,\
     usp10 \
     gdi32 \
 ))
+
+# cl.exe (and thus clang-cl) likes to emit copies of inline functions even when not needed,
+# which means that for e.g. AVX-compiled sources the .o may contain a copy of an inline
+# function built using AVX, and the linker may select that copy as the one to keep, thus
+# introducing AVX code into generic code. Avoid generating such inlines. The flag currently
+# cannot be used for the whole Skia, because code built without the flag cannot use
+# libraries built with the flag, so cl.exe-built VCL would have undefined references.
+ifeq ($(HAVE_LO_CLANG_DLLEXPORTINLINES),TRUE)
+LO_SKIA_AVOID_INLINE_COPIES := -Zc:dllexportInlines-
+endif
+
 else ifeq ($(OS),MACOSX)
 
 $(eval $(call gb_Library_use_system_darwin_frameworks,skia,\
@@ -830,20 +841,25 @@ $(eval $(call gb_Library_add_generated_exception_objects,skia,\
 
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\
     UnpackedTarball/skia/src/opts/SkOpts_avx, $(CXXFLAGS_INTRINSICS_AVX) $(LO_CLANG_CXXFLAGS_INTRINSICS_AVX) \
+        $(LO_SKIA_AVOID_INLINE_COPIES) \
 ))
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\
     UnpackedTarball/skia/src/opts/SkOpts_hsw, \
         $(CXXFLAGS_INTRINSICS_AVX2) $(CXXFLAGS_INTRINSICS_F16C) $(CXXFLAGS_INTRINSICS_FMA) \
         $(LO_CLANG_CXXFLAGS_INTRINSICS_AVX2) $(LO_CLANG_CXXFLAGS_INTRINSICS_F16C) $(LO_CLANG_CXXFLAGS_INTRINSICS_FMA) \
+        $(LO_SKIA_AVOID_INLINE_COPIES) \
 ))
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\
     UnpackedTarball/skia/src/opts/SkOpts_sse41, $(CXXFLAGS_INTRINSICS_SSE41) $(LO_CLANG_CXXFLAGS_INTRINSICS_SSE41) \
+        $(LO_SKIA_AVOID_INLINE_COPIES) \
 ))
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\
     UnpackedTarball/skia/src/opts/SkOpts_sse42, $(CXXFLAGS_INTRINSICS_SSE42) $(LO_CLANG_CXXFLAGS_INTRINSICS_SSE42) \
+        $(LO_SKIA_AVOID_INLINE_COPIES) \
 ))
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\
     UnpackedTarball/skia/src/opts/SkOpts_ssse3, $(CXXFLAGS_INTRINSICS_SSSE3) $(LO_CLANG_CXXFLAGS_INTRINSICS_SSSE3) \
+        $(LO_SKIA_AVOID_INLINE_COPIES) \
 ))
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\
     UnpackedTarball/skia/src/opts/SkOpts_crc32 \
@@ -851,6 +867,7 @@ $(eval $(call gb_Library_add_generated_exception_objects,skia,\
 
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\
     UnpackedTarball/skia/src/opts/SkOpts_skx, $(CXXFLAGS_INTRINSICS_AVX512)  $(LO_CLANG_CXXFLAGS_INTRINSICS_AVX512)\
+        $(LO_SKIA_AVOID_INLINE_COPIES) \
 ))
 
 $(eval $(call gb_Library_add_generated_exception_objects,skia,\