Hi Pali, On Tue, 25 Apr 2023 at 10:21, Pali Rohár <p...@kernel.org> wrote: > > On Monday 24 April 2023 17:08:29 Simon Glass wrote: > > Weak symbols are not well supported by the PE format, so disable them. > > They are supported by PE format. This is likely issue of (older) > toolchain. What about rather requiring better toolchain version and > fix special cases of weak functions do not work correctly?
What compiler are you using? How do weak symbols work in that compiler? I am using: $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-msys/11.3.0/lto-wrapper.exe Target: x86_64-pc-msys Configured with: /c/S/gcc/src/gcc-11.3.0/configure --build=x86_64-pc-msys --prefix=/usr --libexecdir=/usr/lib --enable-bootstrap --enable-shared --enable-shared-libgcc --enable-static --enable-version-specific-runtime-libs --with-arch=x86-64 --with-tune=generic --disable-multilib --enable-__cxa_atexit --with-dwarf2 --enable-languages=c,c++,fortran,lto --enable-graphite --enable-threads=posix --enable-libatomic --enable-libgomp --disable-libitm --enable-libquadmath --enable-libquadmath-support --disable-libssp --disable-win32-registry --disable-symvers --with-gnu-ld --with-gnu-as --disable-isl-version-check --enable-checking=release --without-libiconv-prefix --without-libintl-prefix --with-system-zlib --enable-linker-build-id --with-default-libstdcxx-abi=gcc4-compatible --enable-libstdcxx-filesystem-ts Thread model: posix Supported LTO compression algorithms: zlib gcc version 11.3.0 (GCC) sglass@DESKTOP-OHNGJ4K MINGW64 ~/u-boot $ ld -v GNU ld (GNU Binutils) 2.40 Regards, Simon > > > We need to manually ensure that only one function is present in the source > > code. > > > > Add a Kconfig option to control this and enable it when building for > > Windows. > > > > Signed-off-by: Simon Glass <s...@chromium.org> > > --- > > > > Kconfig | 15 +++++++++++++++ > > include/linux/compiler_attributes.h | 4 ++++ > > 2 files changed, 19 insertions(+) > > > > diff --git a/Kconfig b/Kconfig > > index f24e4f0a331e..ca1402d09d10 100644 > > --- a/Kconfig > > +++ b/Kconfig > > @@ -72,6 +72,21 @@ config CLANG_VERSION > > int > > default $(shell,$(srctree)/scripts/clang-version.sh $(CC)) > > > > +config CC_IS_MSYS > > + def_bool $(success,uname -o | grep -q Msys) > > + > > +config WEAK_SYMBOLS > > + bool "Enable use of weak symbols" > > + default y if !CC_IS_MSYS > > + help > > + The Portable Executable (PE) format used by Windows does not support > > + weak symbols very well. Even where it can be made to work, the > > __weak > > + function attribute cannot be made to work with PE. Supporting weak > > + symbols would involve changing the source code in undesirable ways. > > + > > + This option controls whether weak symbols are used, or not. When > > + disabled, the __weak function attribute does nothing. > > + > > choice > > prompt "Optimization level" > > default CC_OPTIMIZE_FOR_SIZE > > diff --git a/include/linux/compiler_attributes.h > > b/include/linux/compiler_attributes.h > > index 44c9a08d7346..c954109a065b 100644 > > --- a/include/linux/compiler_attributes.h > > +++ b/include/linux/compiler_attributes.h > > @@ -268,6 +268,10 @@ > > * gcc: > > https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute > > * gcc: > > https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute > > */ > > +#ifdef CONFIG_WEAK_SYMBOLS > > #define __weak __attribute__((__weak__)) > > +#else > > +#define __weak > > +#endif > > > > #endif /* __LINUX_COMPILER_ATTRIBUTES_H */ > > -- > > 2.40.0.634.g4ca3ef3211-goog > >
