[PATCH v8 08/17] perf symbol: Avoid use of machine__is

[Ian Rogers]

Switch to using the ELF machine from the dso or running machine rather
than the machine perf_env arch that may fall back on EM_HOST. This
also avoids potentially imprecise string comparisons.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/util/symbol.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index fcaeeddbbb6b..8aaaab0ad4b7 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -851,6 +851,24 @@ static int maps__split_kallsyms_for_kcore(struct maps *kmaps, struct dso *dso)
 	return count;
 }
 
+static uint16_t machine_or_dso_e_machine(struct machine *machine, struct dso *dso)
+{
+	uint16_t e_machine = EM_NONE;
+
+	/* Check for a cached value first. */
+	if (machine && machine->env && machine->env->e_machine != EM_NONE)
+		return machine->env->e_machine;
+
+	/* DSO should be most accurate */
+	if (dso)
+		e_machine = dso__e_machine(dso, machine, /*e_flags=*/NULL);
+
+	if (e_machine != EM_NONE)
+		return e_machine;
+
+	return perf_env__e_machine(machine ? machine->env : NULL, /*e_flags=*/NULL);
+}
+
 /*
  * Split the symbols into maps, making sure there are no overlaps, i.e. the
  * kernel range is broken in several maps, named [kernel].N, as we don't have
@@ -866,14 +884,13 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
 	struct rb_root_cached *root = dso__symbols(dso);
 	struct rb_node *next = rb_first_cached(root);
 	int kernel_range = 0;
-	bool x86_64;
+	uint16_t e_machine = EM_NONE;
 
 	if (!kmaps)
 		return -1;
 
 	machine = maps__machine(kmaps);
-
-	x86_64 = machine__is(machine, "x86_64");
+	e_machine = machine_or_dso_e_machine(machine, dso);
 
 	while (next) {
 		char *module;
@@ -925,7 +942,7 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
 			 */
 			pos->start = map__map_ip(curr_map, pos->start);
 			pos->end   = map__map_ip(curr_map, pos->end);
-		} else if (x86_64 && is_entry_trampoline(pos->name)) {
+		} else if (e_machine == EM_X86_64 && is_entry_trampoline(pos->name)) {
 			/*
 			 * These symbols are not needed anymore since the
 			 * trampoline maps refer to the text section and it's
@@ -1428,7 +1445,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 		free(new_node);
 	}
 
-	if (machine__is(machine, "x86_64")) {
+	if (machine_or_dso_e_machine(machine, dso) == EM_X86_64) {
 		u64 addr;
 
 		/*
@@ -1716,7 +1733,7 @@ int dso__load(struct dso *dso, struct map *map)
 			ret = dso__load_guest_kernel_sym(dso, map);
 
 		machine = maps__machine(map__kmaps(map));
-		if (machine__is(machine, "x86_64"))
+		if (machine_or_dso_e_machine(machine, dso) == EM_X86_64)
 			machine__map_x86_64_entry_trampolines(machine, dso);
 		goto out;
 	}
-- 
2.54.0.545.g6539524ca2-goog