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py/nlrx86: Use naked attribute on nlr_push for gcc 8.0 and higher.

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gcc 8.0 supports the naked attribute for x86 systems so it can now be used
here.  And in fact it is necessary to use this for nlr_push because gcc 8.0
no longer generates a prelude for this function (even without the naked
attribute).
This commit is contained in:
Damien George 2018-05-15 11:17:28 +10:00
parent e6b66f1092
commit c97607db5c
1 changed files with 21 additions and 5 deletions
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26
py/nlrx86.c
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@ -39,15 +39,29 @@ unsigned int nlr_push_tail(nlr_buf_t *nlr) asm("nlr_push_tail");
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr); __attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);
#endif #endif
#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 8
// Since gcc 8.0 the naked attribute is supported
#define USE_NAKED (1)
#define UNDO_PRELUDE (0)
#elif defined(__ZEPHYR__) || defined(__ANDROID__)
// Zephyr and Android use a different calling convention by default
#define USE_NAKED (0)
#define UNDO_PRELUDE (0)
#else
#define USE_NAKED (0)
#define UNDO_PRELUDE (1)
#endif
#if USE_NAKED
__attribute__((naked))
#endif
unsigned int nlr_push(nlr_buf_t *nlr) { unsigned int nlr_push(nlr_buf_t *nlr) {
#if !USE_NAKED
(void)nlr; (void)nlr;
#endif
__asm volatile ( __asm volatile (
// Check for Zephyr, which uses a different calling convention #if UNDO_PRELUDE
// by default.
// TODE: Better support for various x86 calling conventions
// (unfortunately, __attribute__((naked)) is not supported on x86).
#if !(defined(__ZEPHYR__) || defined(__ANDROID__))
"pop %ebp \n" // undo function's prelude "pop %ebp \n" // undo function's prelude
#endif #endif
"mov 4(%esp), %edx \n" // load nlr_buf "mov 4(%esp), %edx \n" // load nlr_buf
@ -61,7 +75,9 @@ unsigned int nlr_push(nlr_buf_t *nlr) {
"jmp nlr_push_tail \n" // do the rest in C "jmp nlr_push_tail \n" // do the rest in C
); );
#if !USE_NAKED
return 0; // needed to silence compiler warning return 0; // needed to silence compiler warning
#endif
} }
NORETURN void nlr_jump(void *val) { NORETURN void nlr_jump(void *val) {