Rewrite {amd64,i386}-pseudo.c to better specify register liveness.

clang was using eax to construct %0 here:

  asm ("mov %%eax, 0(%0)\n\t"
       "mov %%ebx, 4(%0)\n\t"
       "mov %%ecx, 8(%0)\n\t"
       "mov %%edx, 12(%0)\n\t"
       "mov %%esi, 16(%0)\n\t"
       "mov %%edi, 20(%0)\n\t"
       : /* no output operands */
       : "r" (data)
       : "eax", "ebx", "ecx", "edx", "esi", "edi");

which caused amd64-word.exp (and others similarly) to fail.
It's a perfectly legit thing for clang to do given the available data.
The patch fixes this by marking the registers as live from the
time of the preceding breakpoint.

gdb/testsuite/ChangeLog:

	* gdb.arch/amd64-pseudo.c (main): Rewrite to better specify when
	eax,etc. are live with values set by gdb and thus the compiler can't
	use them.
	* gdb.arch/i386-pseudo.c (main): Ditto.
This commit is contained in:
Doug Evans 2014-08-28 11:38:22 -07:00
parent 376c8d5bbb
commit fb0576e983
3 changed files with 59 additions and 23 deletions

View File

@ -1,3 +1,10 @@
2014-08-28 Doug Evans <dje@google.com>
* gdb.arch/amd64-pseudo.c (main): Rewrite to better specify when
eax,etc. are live with values set by gdb and thus the compiler can't
use them.
* gdb.arch/i386-pseudo.c (main): Ditto.
2014-08-27 Doug Evans <dje@google.com>
* lib/gdb.exp (gdb_compile_shlib): Add support for clang.

View File

@ -39,6 +39,21 @@ int data[] = {
int
main (int argc, char **argv)
{
register int eax asm ("eax");
register int ebx asm ("ebx");
register int ecx asm ("ecx");
register int edx asm ("edx");
register int esi asm ("esi");
register int edi asm ("edi");
register long r8 asm ("r8");
register long r9 asm ("r9");
register long r10 asm ("r10");
register long r11 asm ("r11");
register long r12 asm ("r12");
register long r13 asm ("r13");
register long r14 asm ("r14");
register long r15 asm ("r15");
asm ("mov 0(%0), %%eax\n\t"
"mov 4(%0), %%ebx\n\t"
"mov 8(%0), %%ecx\n\t"
@ -61,15 +76,13 @@ main (int argc, char **argv)
: /* no output operands */
: "r" (data)
: "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15");
asm ("nop"); /* second breakpoint here */
/* amd64-dword.exp writes eax-edi here.
Tell gcc they're clobbered so it doesn't try to keep "data" in
one of them. */
asm (""
: /* no outputs */
: /* no inputs */
: "eax", "ebx", "ecx", "edx", "esi", "edi");
asm ("nop" /* second breakpoint here */
/* amd64-{byte,word,dword}.exp write eax-edi here.
Tell gcc/clang they're live. */
: "=r" (eax), "=r" (ebx), "=r" (ecx),
"=r" (edx), "=r" (esi), "=r" (edi)
: /* no inputs */);
asm ("mov %%eax, 0(%0)\n\t"
"mov %%ebx, 4(%0)\n\t"
@ -78,17 +91,18 @@ main (int argc, char **argv)
"mov %%esi, 16(%0)\n\t"
"mov %%edi, 20(%0)\n\t"
: /* no output operands */
: "r" (data)
: "eax", "ebx", "ecx", "edx", "esi", "edi");
asm ("nop"); /* third breakpoint here */
: "r" (data),
/* Mark these as inputs so that gcc/clang won't try to use them as
a temp to build %0. */
"r" (eax), "r" (ebx), "r" (ecx),
"r" (edx), "r" (esi), "r" (edi));
/* amd64-dword.exp writes r8-r15 here.
Tell gcc they're clobbered so it doesn't try to keep "data" in
one of them. */
asm (""
: /* no outputs */
: /* no inputs */
: "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15");
asm ("nop" /* third breakpoint here */
/* amd64-{byte,word,dword}.exp write r8-r15 here.
Tell gcc/clang they're live. */
: "=r" (r8), "=r" (r9), "=r" (r10), "=r" (r11),
"=r" (r12), "=r" (r13), "=r" (r14), "=r" (r15)
: /* no inputs */);
asm ("mov %%r8d, 24(%0)\n\t"
"mov %%r9d, 28(%0)\n\t"
@ -99,8 +113,11 @@ main (int argc, char **argv)
"mov %%r14d, 48(%0)\n\t"
"mov %%r15d, 52(%0)\n\t"
: /* no output operands */
: "r" (data)
: "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15");
: "r" (data),
/* Mark these as inputs so that gcc/clang won't try to use them as
a temp to build %0. */
"r" (r8), "r" (r9), "r" (r10), "r" (r11),
"r" (r12), "r" (r13), "r" (r14), "r" (r15));
puts ("Bye!"); /* forth breakpoint here */
return 0;

View File

@ -29,6 +29,11 @@ int data[] = {
int
main (int argc, char **argv)
{
register int eax asm ("eax");
register int ebx asm ("ebx");
register int ecx asm ("ecx");
register int edx asm ("edx");
asm ("mov 0(%0), %%eax\n\t"
"mov 4(%0), %%ebx\n\t"
"mov 8(%0), %%ecx\n\t"
@ -36,15 +41,22 @@ main (int argc, char **argv)
: /* no output operands */
: "r" (data)
: "eax", "ebx", "ecx", "edx");
asm ("nop"); /* first breakpoint here */
asm ("nop" /* first breakpoint here */
/* i386-{byte,word}.exp write eax-edx here.
Tell gcc/clang they're live. */
: "=r" (eax), "=r" (ebx), "=r" (ecx), "=r" (edx)
: /* no inputs */);
asm ("mov %%eax, 0(%0)\n\t"
"mov %%ebx, 4(%0)\n\t"
"mov %%ecx, 8(%0)\n\t"
"mov %%edx, 12(%0)\n\t"
: /* no output operands */
: "r" (data)
: "eax", "ebx", "ecx", "edx");
: "r" (data),
/* Mark these as inputs so that gcc/clang won't try to use them as
a temp to build %0. */
"r" (eax), "r" (ebx), "r" (ecx), "r" (edx));
puts ("Bye!"); /* second breakpoint here */
return 0;