diff options
Diffstat (limited to 'packages/gcc/11.2.0/0005-libstdc-Add-nostdinc-for-c-17-sources-PR100017.patch')
| -rw-r--r-- | packages/gcc/11.2.0/0005-libstdc-Add-nostdinc-for-c-17-sources-PR100017.patch | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/packages/gcc/11.2.0/0005-libstdc-Add-nostdinc-for-c-17-sources-PR100017.patch b/packages/gcc/11.2.0/0005-libstdc-Add-nostdinc-for-c-17-sources-PR100017.patch new file mode 100644 index 0000000..8851e98 --- /dev/null +++ b/packages/gcc/11.2.0/0005-libstdc-Add-nostdinc-for-c-17-sources-PR100017.patch @@ -0,0 +1,78 @@ +From 4fde88e5dd152fe866a97b12e0f8229970d15cb3 Mon Sep 17 00:00:00 2001 +From: Jonathan Wakely <jwakely@redhat.com> +Date: Fri, 7 Jan 2022 15:21:03 +0000 +Subject: [PATCH] libstdc++: Add -nostdinc++ for c++17 sources [PR100017] + +When building a build!=host compiler, the just-built gcc can't be used +to build the target libstdc++ (because it is built for the host triplet, +not the build triplet). The top-level configure.ac sets up the build +flags for libstdc++ (and other "raw_cxx" libs) like this: + +GCC_TARGET_TOOL(c++ for libstdc++, RAW_CXX_FOR_TARGET, CXX, + [gcc/xgcc -shared-libgcc -B$$r/$(HOST_SUBDIR)/gcc -nostdinc++ -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src/.libs -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/libsupc++/.libs], + c++) + +The -nostdinc++ flag is only used for the IN-TREE-TOOL, i.e. when using +the just-built gcc/xgcc compiler. This means that the cross-compiler +used to build libstdc++ will add its own libstdc++ headers to the +include path. That results in the #include <cfenv> in +src/c++17/floating_to_chars.cc and src/c++17/floating_from_chars.cc +doing #include_next <fenv.h> and finding the libstdc++ fenv.h wrapper +from the host compiler. Because that has the same include guard as the +<fenv.h> in the libstdc++ we're trying to build, we never reach the +underlying <fenv.h> from libc. That results in several errors of the +form: + +error: 'fenv_t' has not been declared in '::' + +The most correct fix would be to add -nostdinc++ to the +RAW_CXX_FOR_TARGET variable in configure.ac, or the +RAW_CXX_TARGET_EXPORTS variable in Makefile.tpl. + +Another solution would be to make the libstdc++ <fenv.h> wrapper use +_GLIBCXX_INCLUDE_NEXT_C_HEADERS like our <stdlib.h> and other C header +wrappers. + +For now though, the simplest and safest solution is to just add +-nostdinc++ to the CXXFLAGS used for src/c++17/*.cc, which is what this +does. + +libstdc++-v3/ChangeLog: + + PR libstdc++/100017 + * src/c++17/Makefile.am (AM_CXXFLAGS): Add -nostdinc++. + * src/c++17/Makefile.in: Regenerate. +--- + libstdc++-v3/src/c++17/Makefile.am | 2 +- + libstdc++-v3/src/c++17/Makefile.in | 2 +- + 2 files changed, 2 insertions(+), 2 deletions(-) + +diff --git a/libstdc++-v3/src/c++17/Makefile.am b/libstdc++-v3/src/c++17/Makefile.am +index f08553a1dd78..3d53f652fac9 100644 +--- a/libstdc++-v3/src/c++17/Makefile.am ++++ b/libstdc++-v3/src/c++17/Makefile.am +@@ -79,7 +79,7 @@ endif + # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden + # as the occasion calls for it. + AM_CXXFLAGS = \ +- -std=gnu++17 \ ++ -std=gnu++17 -nostdinc++ \ + $(glibcxx_lt_pic_flag) $(glibcxx_compiler_shared_flag) \ + $(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \ + $(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS) \ +diff --git a/libstdc++-v3/src/c++17/Makefile.in b/libstdc++-v3/src/c++17/Makefile.in +index 63984ecd52ad..8c02be6514f8 100644 +--- a/libstdc++-v3/src/c++17/Makefile.in ++++ b/libstdc++-v3/src/c++17/Makefile.in +@@ -455,7 +455,7 @@ libc__17convenience_la_SOURCES = $(sources) $(inst_sources) + # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden + # as the occasion calls for it. + AM_CXXFLAGS = \ +- -std=gnu++17 \ ++ -std=gnu++17 -nostdinc++ \ + $(glibcxx_lt_pic_flag) $(glibcxx_compiler_shared_flag) \ + $(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \ + $(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS) \ +-- +2.34.1 + |