From: Nick Desaulniers ndesaulniers@google.com
commit 587f17018a2c6c414e41a312b002faaef60cf423 upstream.
This allows C code to make use of compilers with support for output variables along the fallthrough path via preprocessor define:
CONFIG_CC_HAS_ASM_GOTO_OUTPUT
[ This is not used anywhere yet, and currently released compilers don't support this yet, but it's coming, and I have some local experimental patches to take advantage of it when it does - Linus ]
Signed-off-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- init/Kconfig | 4 ++++ 1 file changed, 4 insertions(+)
--- a/init/Kconfig +++ b/init/Kconfig @@ -38,6 +38,10 @@ config CC_HAS_ASM_GOTO_TIED_OUTPUT # Detect buggy gcc and clang, fixed in gcc-11 clang-14. def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .\n": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null)
+config CC_HAS_ASM_GOTO_OUTPUT + depends on CC_HAS_ASM_GOTO + def_bool $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null) + config TOOLS_SUPPORT_RELR def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)