Build fails with strict-aliasing violations
eli-schwartz opened this issue · comments
I tried to build with the following *FLAGS to optimize the build: -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing
The -Werror=* flags are important to detect cases where the compiler can try to optimize based on assuming UB cannot happen, and miscompile code that has UB in it. strict-aliasing issues are always bad but LTO can make them even worse.
I got this error:
[1/625] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DHAVE_CONFIG_H -DLAF_LINUX -DLAF_SKIA -DNDEBUG -DPNG_NO_MMX_CODE -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/harfbuzz -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/simpleini -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/aseprite-1.3.6_build/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -std=c++17 -MD -MT laf/base/CMakeFiles/laf-base.dir/cfile.cpp.o -MF laf/base/CMakeFiles/laf-base.dir/cfile.cpp.o.d -o laf/base/CMakeFiles/laf-base.dir/cfile.cpp.o -c /var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp
FAILED: laf/base/CMakeFiles/laf-base.dir/cfile.cpp.o
/usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DHAVE_CONFIG_H -DLAF_LINUX -DLAF_SKIA -DNDEBUG -DPNG_NO_MMX_CODE -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/harfbuzz -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/simpleini -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/aseprite-1.3.6_build/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -std=c++17 -MD -MT laf/base/CMakeFiles/laf-base.dir/cfile.cpp.o -MF laf/base/CMakeFiles/laf-base.dir/cfile.cpp.o.d -o laf/base/CMakeFiles/laf-base.dir/cfile.cpp.o -c /var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp: In function ‘float base::fgetf(FILE*)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp:117:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
117 | return *reinterpret_cast<float*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp: In function ‘double base::fgetd(FILE*)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp:159:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
159 | return *reinterpret_cast<double*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp: In function ‘int base::fputf(float, FILE*)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp:234:19: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
234 | const int b = *(reinterpret_cast<int*>(&l));
| ~^~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp: In function ‘int base::fputd(double, FILE*)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/cfile.cpp:257:25: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
257 | const long long b = *(reinterpret_cast<long long*>(&l));
| ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: some warnings being treated as errors
[2/625] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DHAVE_CONFIG_H -DLAF_LINUX -DLAF_SKIA -DNDEBUG -DPNG_NO_MMX_CODE -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/harfbuzz -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/simpleini -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/aseprite-1.3.6_build/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -std=c++17 -MD -MT laf/base/CMakeFiles/laf-base.dir/serialization.cpp.o -MF laf/base/CMakeFiles/laf-base.dir/serialization.cpp.o.d -o laf/base/CMakeFiles/laf-base.dir/serialization.cpp.o -c /var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp
FAILED: laf/base/CMakeFiles/laf-base.dir/serialization.cpp.o
/usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DHAVE_CONFIG_H -DLAF_LINUX -DLAF_SKIA -DNDEBUG -DPNG_NO_MMX_CODE -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/harfbuzz -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/simpleini -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/aseprite-1.3.6_build/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -std=c++17 -MD -MT laf/base/CMakeFiles/laf-base.dir/serialization.cpp.o -MF laf/base/CMakeFiles/laf-base.dir/serialization.cpp.o.d -o laf/base/CMakeFiles/laf-base.dir/serialization.cpp.o -c /var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘std::ostream& base::serialization::little_endian::write_float(std::ostream&, float)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:60:19: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
60 | const int b = *(reinterpret_cast<int*>(&value));
| ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘std::ostream& base::serialization::little_endian::write_double(std::ostream&, double)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:70:25: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
70 | const long long b = *(reinterpret_cast<long long*>(&value));
| ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘float base::serialization::little_endian::read_float(std::istream&)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:129:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
129 | return *reinterpret_cast<float*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘double base::serialization::little_endian::read_double(std::istream&)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:151:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
151 | return *reinterpret_cast<double*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘std::ostream& base::serialization::big_endian::write_float(std::ostream&, float)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:185:19: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
185 | const int b = *(reinterpret_cast<int*>(&value));
| ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘std::ostream& base::serialization::big_endian::write_double(std::ostream&, double)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:195:25: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
195 | const long long b = *(reinterpret_cast<long long*>(&value));
| ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘float base::serialization::big_endian::read_float(std::istream&)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:254:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
254 | return *reinterpret_cast<float*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp: In function ‘double base::serialization::big_endian::read_double(std::istream&)’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf/base/serialization.cpp:276:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
276 | return *reinterpret_cast<double*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: some warnings being treated as errors
[3/625] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DENABLE_DATA_RECOVERY -DENABLE_NEWS -DENABLE_SAVE -DENABLE_SCRIPTING -DENABLE_UI -DENABLE_WEBSOCKET -DHAVE_CONFIG_H -DHAVE_CONFIG_OVERRIDE_H=1 -DLAF_LINUX -DLAF_SKIA -DLAF_WITH_REGION -DNDEBUG -DPNG_NO_MMX_CODE -DSK_ALLOW_STATIC_GLOBAL_INITIALIZERS=1 -DSK_BUILD_FOR_UNIX -DSK_ENABLE_SKSL=1 -DSK_GAMMA_APPLY_TO_A8 -DSK_GAMMA_SRGB -DSK_GL=1 -DSK_INTERNAL -DSK_R32_SHIFT=16 -DSK_SCALAR_TO_FLOAT_EXCLUDED -DSK_SUPPORT_GPU=1 -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/harfbuzz -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/simpleini -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/observable -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/.. -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/aseprite-1.3.6_build/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/fixmath/.. -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/doc/.. -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/skia-3338e90707323d2cd3a150276acb9f39933deee2 -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/cityhash/src -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -Wall -Wno-switch -Wimplicit-fallthrough -std=c++17 -Wno-sign-compare -MD -MT src/dio/CMakeFiles/dio-lib.dir/aseprite_decoder.cpp.o -MF src/dio/CMakeFiles/dio-lib.dir/aseprite_decoder.cpp.o.d -o src/dio/CMakeFiles/dio-lib.dir/aseprite_decoder.cpp.o -c /var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/aseprite_decoder.cpp
FAILED: src/dio/CMakeFiles/dio-lib.dir/aseprite_decoder.cpp.o
/usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DENABLE_DATA_RECOVERY -DENABLE_NEWS -DENABLE_SAVE -DENABLE_SCRIPTING -DENABLE_UI -DENABLE_WEBSOCKET -DHAVE_CONFIG_H -DHAVE_CONFIG_OVERRIDE_H=1 -DLAF_LINUX -DLAF_SKIA -DLAF_WITH_REGION -DNDEBUG -DPNG_NO_MMX_CODE -DSK_ALLOW_STATIC_GLOBAL_INITIALIZERS=1 -DSK_BUILD_FOR_UNIX -DSK_ENABLE_SKSL=1 -DSK_GAMMA_APPLY_TO_A8 -DSK_GAMMA_SRGB -DSK_GL=1 -DSK_INTERNAL -DSK_R32_SHIFT=16 -DSK_SCALAR_TO_FLOAT_EXCLUDED -DSK_SUPPORT_GPU=1 -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/harfbuzz -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/simpleini -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/observable -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/.. -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/aseprite-1.3.6_build/laf -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/fixmath/.. -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/doc/.. -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/skia-3338e90707323d2cd3a150276acb9f39933deee2 -I/var/tmp/portage/dev-games/aseprite-1.3.6/work/third_party/cityhash/src -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -Wall -Wno-switch -Wimplicit-fallthrough -std=c++17 -Wno-sign-compare -MD -MT src/dio/CMakeFiles/dio-lib.dir/aseprite_decoder.cpp.o -MF src/dio/CMakeFiles/dio-lib.dir/aseprite_decoder.cpp.o.d -o src/dio/CMakeFiles/dio-lib.dir/aseprite_decoder.cpp.o -c /var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/aseprite_decoder.cpp
/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/aseprite_decoder.cpp: In member function ‘float dio::AsepriteDecoder::readFloat()’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/aseprite_decoder.cpp:428:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
428 | return *reinterpret_cast<float*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/aseprite_decoder.cpp: In member function ‘double dio::AsepriteDecoder::readDouble()’:
/var/tmp/portage/dev-games/aseprite-1.3.6/work/src/dio/aseprite_decoder.cpp:468:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
468 | return *reinterpret_cast<double*>(&v);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: some warnings being treated as errors
ninja: build stopped: cannot make progress due to previous errors.
Originally reported downstream: https://bugs.gentoo.org/924692
Full build log: build.log
Recent laf main code don't has reinterpret_cast invocations, so these errors may be fixed by fetching recent laf codebase.
My report is about 1.3.6
Which part of the commits since 1.3.6 do you believe solved this issue?
Sorry, misread source code. Proposed PR aseprite/laf#84 intended to fix this.