Hi Pali,
On Tue, 25 Apr 2023 at 10:21, Pali Rohár pali@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 sjg@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_MSYShelpThe Portable Executable (PE) format used by Windows does not supportweak symbols very well. Even where it can be made to work, the __weakfunction attribute cannot be made to work with PE. Supporting weaksymbols would involve changing the source code in undesirable ways.This option controls whether weak symbols are used, or not. Whendisabled, 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-wea...
- gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-wea...
*/ +#ifdef CONFIG_WEAK_SYMBOLS #define __weak __attribute__((__weak__)) +#else +#define __weak +#endif
#endif /* __LINUX_COMPILER_ATTRIBUTES_H */
2.40.0.634.g4ca3ef3211-goog