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Hi,
I am discovering clang's compiler flags as HPA writes in [0]...
"-fgnu-inlines would be a better option.
We could also simply #define inline inline __attribute__((gnu_inline))"
[1] says on clang-7 compiler-flags...
Generate output compatible with the standard GNU Objective-C runtime
-fgnu89-inline, -fno-gnu89-inline
...and...
Place each function in its own section (ELF Only)
-fgnu-inline-asm, -fno-gnu-inline-asm
Should that be '-fgnu89-inline'?
You happen to know what '-fgnu-inline-asm' does and it is an option?
This what Linux v4.17 says about inline defines...
[ include/linux/compiler-gcc.h ]
...
/*
* Force always-inline if the user requests it so via the .config,
* or if gcc is too old.
* GCC does not warn about unused static inline functions for
* -Wunused-function. This turns out to avoid the need for complex #ifdef
* directives. Suppress the warning in clang as well by using "unused"
* function attribute, which is redundant but not harmful for gcc.
*/
#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
!defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
#define inline inline __attribute__((always_inline,unused)) notrace
#define __inline__ __inline__ __attribute__((always_inline,unused)) notrace
#define __inline __inline __attribute__((always_inline,unused)) notrace
#else
/* A lot of inline functions can cause havoc with function tracing */
#define inline inline __attribute__((unused)) notrace
#define __inline__ __inline__ __attribute__((unused)) notrace
#define __inline __inline __attribute__((unused)) notrace
#endif
...
[ include/linux/compiler_types.h ]
...
/*
* Allow us to avoid 'defined but not used' warnings on functions and data,
* as well as force them to be emitted to the assembly file.
*
* As of gcc 3.4, static functions that are not marked with attribute((used))
* may be elided from the assembly file. As of gcc 3.4, static data not so
* marked will not be elided, but this may change in a future gcc version.
*
* NOTE: Because distributions shipped with a backported unit-at-a-time
* compiler in gcc 3.3, we must define __used to be __attribute__((used))
* for gcc >=3.3 instead of 3.4.
*
* In prior versions of gcc, such functions and data would be emitted, but
* would be warned about except with attribute((unused)).
*
* Mark functions that are referenced only in inline assembly as __used so
* the code is emitted even though it appears to be unreferenced.
*/
#ifndef __used
# define __used /* unimplemented */
#endif
#ifndef __maybe_unused
# define __maybe_unused /* unimplemented */
#endif
#ifndef __always_unused
# define __always_unused /* unimplemented */
#endif
#ifndef noinline
#define noinline
#endif
/*
* Rather then using noinline to prevent stack consumption, use
* noinline_for_stack instead. For documentation reasons.
*/
#define noinline_for_stack noinline
#ifndef __always_inline
#define __always_inline inline
#endif
...
Regards,
- Sedat -
[0] https://patchwork.kernel.org/patch/10444075/
[1] https://clang.llvm.org/docs/ClangCommandLineReference.html
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