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perf annotate-data: Invalidate caller-saved regs for all calls

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Previously, the x86 call handler returned early without invalidating
caller-saved registers when the call target symbol could not be resolved
(func == NULL). This violated the ABI which requires caller-saved
registers to be considered clobbered after any call instruction.

Fix this by:
1. Always invalidating caller-saved registers for any call instruction
   (except __fentry__ which preserves registers)
2. Using dl->ops.target.name as fallback when func->name is unavailable,
   allowing return type lookup for more call targets

This is a conservative change that may reduce type coverage for indirect
calls (e.g., callq *(%rax)) where we cannot determine the return type
but it ensures correctness.

Signed-off-by: Zecheng Li <zli94@ncsu.edu>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Zecheng Li
2026-03-09 13:55:22 -04:00
committed by Namhyung Kim
parent 22b320777c
commit d35b0d5877
1 changed files with 13 additions and 6 deletions
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19
tools/perf/util/annotate-arch/annotate-x86.c
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@@ -229,24 +229,31 @@ static void update_insn_state_x86(struct type_state *state,
if (ins__is_call(&dl->ins)) {
struct symbol *func = dl->ops.target.sym;
const char *call_name;
if (func == NULL)
return;
/* Try to resolve the call target name */
if (func)
call_name = func->name;
else
call_name = dl->ops.target.name;
/* __fentry__ will preserve all registers */
if (!strcmp(func->name, "__fentry__"))
if (call_name && !strcmp(call_name, "__fentry__"))
return;
pr_debug_dtp("call [%x] %s\n", insn_offset, func->name);
if (call_name)
pr_debug_dtp("call [%x] %s\n", insn_offset, call_name);
else
pr_debug_dtp("call [%x] <unknown>\n", insn_offset);
/* Otherwise invalidate caller-saved registers after call */
/* Invalidate caller-saved registers after call (ABI requirement) */
for (unsigned i = 0; i < ARRAY_SIZE(state->regs); i++) {
if (state->regs[i].caller_saved)
invalidate_reg_state(&state->regs[i]);
}
/* Update register with the return type (if any) */
if (die_find_func_rettype(cu_die, func->name, &type_die)) {
if (call_name && die_find_func_rettype(cu_die, call_name, &type_die)) {
tsr = &state->regs[state->ret_reg];
tsr->type = type_die;
tsr->kind = TSR_KIND_TYPE;