[PATCH v2 07/12] perf disasm: Rework the string arch__is to use the ELF machine

Ian Rogers
2026-01-22T16:54:31Z

Add new arch__is_x86 and arch__is_powerpc functions that avoid string
comparisons and use the ELF machine. Remove arch__is that is no longer
used.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/annotate-data.c | 10 +++++-----
tools/perf/util/annotate.c | 16 ++++++++--------
tools/perf/util/capstone.c | 2 +-
tools/perf/util/disasm.c | 15 ++++++++++-----
tools/perf/util/disasm.h | 3 ++-
tools/perf/util/llvm.c | 2 +-
6 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index edfcd6e9df9c..44fbd41e3845 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -165,7 +165,7 @@ static void init_type_state(struct type_state *state, const struct arch *arch)
memset(state, 0, sizeof(*state));
INIT_LIST_HEAD(&state->stack_vars);

- if (arch__is(arch, "x86")) {
+ if (arch__is_x86(arch)) {
state->regs[0].caller_saved = true;
state->regs[1].caller_saved = true;
state->regs[2].caller_saved = true;
@@ -526,7 +526,7 @@ static enum type_match_result check_variable(struct data_loc_info *dloc,
needs_pointer = false;
else if (reg == dloc->fbreg || is_fbreg)
needs_pointer = false;
- else if (arch__is(dloc->arch, "x86") && reg == X86_REG_SP)
+ else if (arch__is_x86(dloc->arch) && reg == X86_REG_SP)
needs_pointer = false;

/* Get the type of the variable */
@@ -1071,7 +1071,7 @@ static void delete_var_types(struct die_var_type *var_types)
/* should match to is_stack_canary() in util/annotate.c */
static void setup_stack_canary(struct data_loc_info *dloc)
{
- if (arch__is(dloc->arch, "x86")) {
+ if (arch__is_x86(dloc->arch)) {
dloc->op->segment = INSN_SEG_X86_GS;
dloc->op->imm = true;
dloc->op->offset = 40;
@@ -1311,7 +1311,7 @@ static enum type_match_result check_matching_type(struct type_state *state,

/* Direct this-cpu access like "%gs:0x34740" */
if (dloc->op->segment == INSN_SEG_X86_GS && dloc->op->imm &&
- arch__is(dloc->arch, "x86")) {
+ arch__is_x86(dloc->arch)) {
pr_debug_dtp("this-cpu var");

addr = dloc->op->offset;
@@ -1397,7 +1397,7 @@ static enum type_match_result find_data_type_insn(struct data_loc_info *dloc,

static int arch_supports_insn_tracking(struct data_loc_info *dloc)
{
- if ((arch__is(dloc->arch, "x86")) || (arch__is(dloc->arch, "powerpc")))
+ if ((arch__is_x86(dloc->arch)) || (arch__is_powerpc(dloc->arch)))
return 1;
return 0;
}
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 132af2556aec..79702072568b 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -2474,7 +2474,7 @@ static int extract_reg_offset(const struct arch *arch, const char *str,
* %gs:0x18(%rbx). In that case it should skip the part.
*/
if (*str == arch->objdump.register_char) {
- if (arch__is(arch, "x86")) {
+ if (arch__is_x86(arch)) {
/* FIXME: Handle other segment registers */
if (!strncmp(str, "%gs:", 4))
op_loc->segment = INSN_SEG_X86_GS;
@@ -2571,7 +2571,7 @@ int annotate_get_insn_location(const struct arch *arch, struct disasm_line *dl,
op_loc->reg2 = -1;

if (insn_str == NULL) {
- if (!arch__is(arch, "powerpc"))
+ if (!arch__is_powerpc(arch))
continue;
}

@@ -2580,7 +2580,7 @@ int annotate_get_insn_location(const struct arch *arch, struct disasm_line *dl,
* required fields for op_loc, ie reg1, reg2, offset from the
* raw instruction.
*/
- if (arch__is(arch, "powerpc")) {
+ if (arch__is_powerpc(arch)) {
op_loc->mem_ref = mem_ref;
op_loc->multi_regs = multi_regs;
get_powerpc_regs(dl->raw.raw_insn, !i, op_loc);
@@ -2591,7 +2591,7 @@ int annotate_get_insn_location(const struct arch *arch, struct disasm_line *dl,
} else {
char *s, *p = NULL;

- if (arch__is(arch, "x86")) {
+ if (arch__is_x86(arch)) {
/* FIXME: Handle other segment registers */
if (!strncmp(insn_str, "%gs:", 4)) {
op_loc->segment = INSN_SEG_X86_GS;
@@ -2675,7 +2675,7 @@ static struct annotated_item_stat *annotate_data_stat(struct list_head *head,

static bool is_stack_operation(const struct arch *arch, struct disasm_line *dl)
{
- if (arch__is(arch, "x86")) {
+ if (arch__is_x86(arch)) {
if (!strncmp(dl->ins.name, "push", 4) ||
!strncmp(dl->ins.name, "pop", 3) ||
!strncmp(dl->ins.name, "call", 4) ||
@@ -2689,7 +2689,7 @@ static bool is_stack_operation(const struct arch *arch, struct disasm_line *dl)
static bool is_stack_canary(const struct arch *arch, struct annotated_op_loc *loc)
{
/* On x86_64, %gs:40 is used for stack canary */
- if (arch__is(arch, "x86")) {
+ if (arch__is_x86(arch)) {
if (loc->segment == INSN_SEG_X86_GS && loc->imm &&
loc->offset == 40)
return true;
@@ -2704,7 +2704,7 @@ static bool is_stack_canary(const struct arch *arch, struct annotated_op_loc *lo
*/
static bool is_address_gen_insn(const struct arch *arch, struct disasm_line *dl)
{
- if (arch__is(arch, "x86")) {
+ if (arch__is_x86(arch)) {
if (!strncmp(dl->ins.name, "lea", 3))
return true;
}
@@ -2847,7 +2847,7 @@ __hist_entry__get_data_type(struct hist_entry *he, const struct arch *arch,
}

/* This CPU access in kernel - pretend PC-relative addressing */
- if (dso__kernel(map__dso(ms->map)) && arch__is(arch, "x86") &&
+ if (dso__kernel(map__dso(ms->map)) && arch__is_x86(arch) &&
op_loc->segment == INSN_SEG_X86_GS && op_loc->imm) {
dloc.var_addr = op_loc->offset;
op_loc->reg1 = DWARF_REG_PC;
diff --git a/tools/perf/util/capstone.c b/tools/perf/util/capstone.c
index 2c7feab61b7b..ce06cfd253ef 100644
--- a/tools/perf/util/capstone.c
+++ b/tools/perf/util/capstone.c
@@ -147,7 +147,7 @@ static void print_capstone_detail(cs_insn *insn, char *buf, size_t len,
struct symbol *sym;

/* TODO: support more architectures */
- if (!arch__is(args->arch, "x86"))
+ if (!arch__is_x86(args->arch))
return;

if (insn->detail == NULL)
diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index 2793697ce75c..b7523256c4ad 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -228,9 +228,14 @@ const struct arch *arch__find(const char *name)
return bsearch(name, architectures, nmemb, sizeof(struct arch), arch__key_cmp);
}

-bool arch__is(const struct arch *arch, const char *name)
+bool arch__is_x86(const struct arch *arch)
{
- return !strcmp(arch->name, name);
+ return arch->e_machine == EM_386 || arch->e_machine == EM_X86_64;
+}
+
+bool arch__is_powerpc(const struct arch *arch)
+{
+ return arch->e_machine == EM_PPC || arch->e_machine == EM_PPC64;
}

static void ins_ops__delete(struct ins_operands *ops)
@@ -877,7 +882,7 @@ static const struct ins_ops *__ins__find(const struct arch *arch, const char *na
struct ins *ins;
const int nmemb = arch->nr_instructions;

- if (arch__is(arch, "powerpc")) {
+ if (arch__is_powerpc(arch)) {
/*
* For powerpc, identify the instruction ops
* from the opcode using raw_insn.
@@ -1066,7 +1071,7 @@ struct disasm_line *disasm_line__new(struct annotate_args *args)
goto out_delete;

if (args->offset != -1) {
- if (arch__is(args->arch, "powerpc")) {
+ if (arch__is_powerpc(args->arch)) {
if (disasm_line__parse_powerpc(dl, args) < 0)
goto out_free_line;
} else if (disasm_line__parse(dl->al.line, &dl->ins.name, &dl->ops.raw) < 0)
@@ -1700,7 +1705,7 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
* and typeoff, disassemble to mnemonic notation is not required in
* case of powerpc.
*/
- if (arch__is(args->arch, "powerpc")) {
+ if (arch__is_powerpc(args->arch)) {
extern const char *sort_order;

if (sort_order && !strstr(sort_order, "sym")) {
diff --git a/tools/perf/util/disasm.h b/tools/perf/util/disasm.h
index 4f5c9a985786..db7f1ee3d8e7 100644
--- a/tools/perf/util/disasm.h
+++ b/tools/perf/util/disasm.h
@@ -106,7 +106,8 @@ struct annotate_args {
};

const struct arch *arch__find(const char *name);
-bool arch__is(const struct arch *arch, const char *name);
+bool arch__is_x86(const struct arch *arch);
+bool arch__is_powerpc(const struct arch *arch);

const struct ins_ops *ins__find(const struct arch *arch, const char *name, struct disasm_line *dl);

diff --git a/tools/perf/util/llvm.c b/tools/perf/util/llvm.c
index 4ada9a10bd93..0d126d233c01 100644
--- a/tools/perf/util/llvm.c
+++ b/tools/perf/util/llvm.c
@@ -146,7 +146,7 @@ int symbol__disassemble_llvm(const char *filename, struct symbol *sym,
return errno;

init_llvm();
- if (arch__is(args->arch, "x86")) {
+ if (arch__is_x86(args->arch)) {
const char *triplet = is_64bit ? "x86_64-pc-linux" : "i686-pc-linux";

disasm = LLVMCreateDisasm(triplet, &storage, /*tag_type=*/0,
--
2.52.0.457.g6b5491de43-goog