OSO/TinyCC
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

x86-64-asm: Accept high register in clobbers

Browse Source 
The callee saved registers (among them r12-r15) really need
saving/restoring if mentioned in asm clobbers, even if TCC
itself doesn't use them.  E.g. the linux kernel relies on that
in its switch_to() implementation.
This commit is contained in:
Michael Matz
2016-10-08 22:50:16 +02:00
parent ddd461dcc8
commit a2a596e767
3 changed files with 53 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
tests/tcctest.c
View File

@ -2925,6 +2925,29 @@ void fancy_copy2 (unsigned *in, unsigned *out)
void fancy_copy2 (unsigned *in, unsigned *out)
{
asm volatile ("mov %0,(%1)" : : "r" (*in), "r" (out) : "memory");
}
#ifdef __x86_64__
void clobber_r12(void)
{
asm volatile("mov $1, %%r12" ::: "r12");
}
#endif
void test_high_clobbers(void)
{
#ifdef __x86_64__
register long val asm("r12");
long val2;
/* This tests if asm clobbers correctly save/restore callee saved
registers if they are clobbered and if it's the high 8 x86-64
registers. This is fragile for GCC as the constraints do not
correctly capture the data flow, but good enough for us. */
asm volatile("mov $0x4542, %%r12" : "=r" (val):: "memory");
clobber_r12();
asm volatile("mov %%r12, %0" : "=r" (val2) : "r" (val): "memory");
printf("asmhc: 0x%x\n", val2);
#endif
}
void asm_test(void)
@ -3004,6 +3027,7 @@ void asm_test(void)
val = 44;
fancy_copy2 (&val, &val2);
printf ("fancycpy2(%d)=%d\n", val, val2);
asm volatile ("mov $0x4243, %%esi" : "=r" (regvar));
printf ("regvar=%x\n", regvar);
test_high_clobbers();
return;