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Fix crashes on 32-bit async client lib when -fomit-frame-pointer

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- Ensure asm parameters are in registers, so we do not de-reference from
   bogus stack pointer.

 - Make return address undefined in DWARF unwind info in my_context_spawn,
   so DWARF-based unwinders will know this is the end of the call stack
   (same as the amd64 fix for the similar issue).
This commit is contained in:
unknown 2012-10-31 12:47:25 +01:00
parent bc5232a65d
commit 27bcea09e5
1 changed files with 16 additions and 5 deletions
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21
mysys/my_context.c
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@ -437,6 +437,8 @@ my_context_destroy(struct my_context *c)
int
my_context_spawn(struct my_context *c, void (*f)(void *), void *d)
{
void (*tmp_f)(void *)= f;
void *tmp_d= d;
int ret;
DBUG_SWAP_CODE_STATE(&c->dbug_state);
@ -454,6 +456,15 @@ my_context_spawn(struct my_context *c, void (*f)(void *), void *d)
(
"movl %%esp, (%[save])\n\t"
"movl %[stack], %%esp\n\t"
#if __GNUC__ >= 4 && __GNUC_MINOR__ >= 4
/*
This emits a DWARF DW_CFA_undefined directive to make the return address
undefined. This indicates that this is the top of the stack frame, and
helps tools that use DWARF stack unwinding to obtain stack traces.
(I use numeric constant to avoid a dependency on libdwarf includes).
*/
".cfi_escape 0x07, 8\n\t"
#endif
/* Push the parameter on the stack. */
"pushl %[d]\n\t"
"movl %%ebp, 4(%[save])\n\t"
@ -483,13 +494,13 @@ my_context_spawn(struct my_context *c, void (*f)(void *), void *d)
"3:\n\t"
"movl $1, %[ret]\n"
"4:\n"
: [ret] "=a" (ret)
: [ret] "=a" (ret),
[f] "+c" (tmp_f),
[d] "+d" (tmp_d)
: [stack] "a" (c->stack_top),
/* Need this in callee-save register to preserve across function call. */
[save] "D" (&c->save[0]),
[f] "m" (f),
[d] "m" (d)
: "ecx", "edx", "memory", "cc"
[save] "D" (&c->save[0])
: "memory", "cc"
);
DBUG_SWAP_CODE_STATE(&c->dbug_state);