f9d1425007
These compiler versions are known to miscompile __weak functions and
thus generate kernels that don't necessarily work correctly. If a weak
function is int he same compilation unit as a caller, gcc may end up
inlining it, and thus binding the weak function too early.
See
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
for details.
Cc: Adrian Bunk <bunk@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
37 lines
1.3 KiB
C
37 lines
1.3 KiB
C
#ifndef __LINUX_COMPILER_H
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#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
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#endif
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/* GCC 4.1.[01] miscompiles __weak */
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#if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
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# error Your version of gcc miscompiles the __weak directive
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#endif
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#define __used __attribute__((__used__))
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#define __must_check __attribute__((warn_unused_result))
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#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
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#define __always_inline inline __attribute__((always_inline))
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/*
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* A trick to suppress uninitialized variable warning without generating any
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* code
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*/
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#define uninitialized_var(x) x = x
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#if __GNUC_MINOR__ >= 3
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/* Mark functions as cold. gcc will assume any path leading to a call
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to them will be unlikely. This means a lot of manual unlikely()s
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are unnecessary now for any paths leading to the usual suspects
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like BUG(), printk(), panic() etc. [but let's keep them for now for
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older compilers]
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Early snapshots of gcc 4.3 don't support this and we can't detect this
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in the preprocessor, but we can live with this because they're unreleased.
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Maketime probing would be overkill here.
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gcc also has a __attribute__((__hot__)) to move hot functions into
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a special section, but I don't see any sense in this right now in
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the kernel context */
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#define __cold __attribute__((__cold__))
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#endif
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