When updating instruction states, the call instruction should play a
role since it can change the register states. For simplicity, mark some
registers as scratch registers (should be arch-dependent), and
invalidate them all after a function call.
If the function returns something, the designated register (ret_reg)
will have the type info.
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/util/annotate-data.c | 45 +++++++++++++++++++++++++++++++--
1 file changed, 43 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index bbd271cd3419..54791dfc6244 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -22,10 +22,14 @@
#include "symbol.h"
#include "symbol_conf.h"
-/* Type information in a register, valid when ok is true */
+/*
+ * Type information in a register, valid when @ok is true.
+ * The @scratch registers are invalidated after a function call.
+ */
struct type_state_reg {
Dwarf_Die type;
bool ok;
+ bool scratch;
};
/* Type information in a stack location, dynamically allocated */
@@ -49,6 +53,7 @@ struct type_state_stack {
struct type_state {
struct type_state_reg regs[TYPE_STATE_MAX_REGS];
struct list_head stack_vars;
+ int ret_reg;
};
static bool has_reg_type(struct type_state *state, int reg)
@@ -56,10 +61,23 @@ static bool has_reg_type(struct type_state *state, int reg)
return (unsigned)reg < ARRAY_SIZE(state->regs);
}
-void init_type_state(struct type_state *state, struct arch *arch __maybe_unused)
+void init_type_state(struct type_state *state, struct arch *arch)
{
memset(state, 0, sizeof(*state));
INIT_LIST_HEAD(&state->stack_vars);
+
+ if (arch__is(arch, "x86")) {
+ state->regs[0].scratch = true;
+ state->regs[1].scratch = true;
+ state->regs[2].scratch = true;
+ state->regs[4].scratch = true;
+ state->regs[5].scratch = true;
+ state->regs[8].scratch = true;
+ state->regs[9].scratch = true;
+ state->regs[10].scratch = true;
+ state->regs[11].scratch = true;
+ state->ret_reg = 0;
+ }
}
void exit_type_state(struct type_state *state)
@@ -416,6 +434,29 @@ void update_insn_state(struct type_state *state, struct data_loc_info *dloc,
int fbreg = dloc->fbreg;
int fboff = 0;
+ if (ins__is_call(&dl->ins)) {
+ Dwarf_Die func_die;
+
+ /* __fentry__ will preserve all registers */
+ if (dl->ops.target.sym &&
+ !strcmp(dl->ops.target.sym->name, "__fentry__"))
+ return;
+
+ /* Otherwise invalidate scratch registers after call */
+ for (unsigned i = 0; i < ARRAY_SIZE(state->regs); i++) {
+ if (state->regs[i].scratch)
+ state->regs[i].ok = false;
+ }
+
+ /* Update register with the return type (if any) */
+ if (die_find_realfunc(cu_die, dl->ops.target.addr, &func_die) &&
+ die_get_real_type(&func_die, &type_die)) {
+ state->regs[state->ret_reg].type = type_die;
+ state->regs[state->ret_reg].ok = true;
+ }
+ return;
+ }
+
/* FIXME: remove x86 specific code and handle more instructions like LEA */
if (!strstr(dl->ins.name, "mov"))
return;
--
2.42.0.869.gea05f2083d-goog
|