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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-21 09:47:19 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-21 09:47:19 -0700 |
| commit | 227c3e9eb5cf3552c2cc83225df6d14adb05f8e8 (patch) | |
| tree | 529caf68f7c4a670813ecddb718e5118ce3cef70 /init | |
| parent | 56c631f5aec35117b0b5862a09a447a72dfbd678 (diff) | |
| parent | 32ee8230b2b06c50f583e14fcd174d7d2edb52f5 (diff) | |
Merge tag 'compiler-attributes-for-linus-v5.4' of git://github.com/ojeda/linux
Pull asm inline support from Miguel Ojeda:
"Make use of gcc 9's "asm inline()" (Rasmus Villemoes):
gcc 9+ (and gcc 8.3, 7.5) provides a way to override the otherwise
crude heuristic that gcc uses to estimate the size of the code
represented by an asm() statement. From the gcc docs
If you use 'asm inline' instead of just 'asm', then for inlining
purposes the size of the asm is taken as the minimum size, ignoring
how many instructions GCC thinks it is.
For compatibility with older compilers, we obviously want a
#if [understands asm inline]
#define asm_inline asm inline
#else
#define asm_inline asm
#endif
But since we #define the identifier inline to attach some attributes,
we have to use an alternate spelling of that keyword. gcc provides
both __inline__ and __inline, and we currently #define both to inline,
so they all have the same semantics.
We have to free up one of __inline__ and __inline, and the latter is
by far the easiest.
The two x86 changes cause smaller code gen differences than I'd
expect, but I think we do want the asm_inline thing available sooner
or later, so this is just to get the ball rolling"
* tag 'compiler-attributes-for-linus-v5.4' of git://github.com/ojeda/linux:
x86: bug.h: use asm_inline in _BUG_FLAGS definitions
x86: alternative.h: use asm_inline for all alternative variants
compiler-types.h: add asm_inline definition
compiler_types.h: don't #define __inline
lib/zstd/mem.h: replace __inline by inline
staging: rtl8723bs: replace __inline by inline
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index f4534c58342d..7020238fd263 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -33,6 +33,9 @@ config CC_HAS_ASM_GOTO config TOOLS_SUPPORT_RELR def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) +config CC_HAS_ASM_INLINE + def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) + config CC_HAS_WARN_MAYBE_UNINITIALIZED def_bool $(cc-option,-Wmaybe-uninitialized) help |