perf annotate: Use an array for the disassembler preference

[ Upstream commit bde4ccfd5ab5361490514fc4af7497989cfbee17 ]

Prior to this change a string was used which could cause issues with
an unrecognized disassembler in symbol__disassembler. Change to
initializing an array of perf_disassembler enum values. If a value
already exists then adding it a second time is ignored to avoid array
out of bounds problems present in the previous code, it also allows a
statically sized array and removes memory allocation needs. Errors in
the disassembler string are reported when the config is parsed during
perf annotate or perf top start up. If the array is uninitialized
after processing the config file the default llvm, capstone then
objdump values are added but without a need to parse a string.

Fixes: a6e8a58de629 ("perf disasm: Allow configuring what disassemblers to use")
Closes: https://lore.kernel.org/lkml/CAP-5=fUdfCyxmEiTpzS2uumUp3-SyQOseX2xZo81-dQtWXj6vA@mail.gmail.com/
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20250124043856.1177264-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 15 insertions, 68 deletions

diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index 41a2b08670dc5..28ceb76e465ba 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -2213,56 +2213,6 @@ out_free_command:
 	return err;
 }
 
-static int annotation_options__init_disassemblers(struct annotation_options *options)
-{
-	char *disassembler;
-
-	if (options->disassemblers_str == NULL) {
-		const char *default_disassemblers_str =
-#ifdef HAVE_LIBLLVM_SUPPORT
-				"llvm,"
-#endif
-#ifdef HAVE_LIBCAPSTONE_SUPPORT
-				"capstone,"
-#endif
-				"objdump";
-
-		options->disassemblers_str = strdup(default_disassemblers_str);
-		if (!options->disassemblers_str)
-			goto out_enomem;
-	}
-
-	disassembler = strdup(options->disassemblers_str);
-	if (disassembler == NULL)
-		goto out_enomem;
-
-	while (1) {
-		char *comma = strchr(disassembler, ',');
-
-		if (comma != NULL)
-			*comma = '\0';
-
-		options->disassemblers[options->nr_disassemblers++] = strim(disassembler);
-
-		if (comma == NULL)
-			break;
-
-		disassembler = comma + 1;
-
-		if (options->nr_disassemblers >= MAX_DISASSEMBLERS) {
-			pr_debug("annotate.disassemblers can have at most %d entries, ignoring \"%s\"\n",
-				 MAX_DISASSEMBLERS, disassembler);
-			break;
-		}
-	}
-
-	return 0;
-
-out_enomem:
-	pr_err("Not enough memory for annotate.disassemblers\n");
-	return -1;
-}
-
 int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
 {
 	struct annotation_options *options = args->options;
@@ -2271,7 +2221,6 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
 	char symfs_filename[PATH_MAX];
 	bool delete_extract = false;
 	struct kcore_extract kce;
-	const char *disassembler;
 	bool decomp = false;
 	int err = dso__disassemble_filename(dso, symfs_filename, sizeof(symfs_filename));
 
@@ -2331,28 +2280,26 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
 		}
 	}
 
-	err = annotation_options__init_disassemblers(options);
-	if (err)
-		goto out_remove_tmp;
-
 	err = -1;
+	for (u8 i = 0; i < ARRAY_SIZE(options->disassemblers) && err != 0; i++) {
+		enum perf_disassembler dis = options->disassemblers[i];
 
-	for (int i = 0; i < options->nr_disassemblers && err != 0; ++i) {
-		disassembler = options->disassemblers[i];
-
-		if (!strcmp(disassembler, "llvm"))
+		switch (dis) {
+		case PERF_DISASM_LLVM:
 			err = symbol__disassemble_llvm(symfs_filename, sym, args);
-		else if (!strcmp(disassembler, "capstone"))
+			break;
+		case PERF_DISASM_CAPSTONE:
 			err = symbol__disassemble_capstone(symfs_filename, sym, args);
-		else if (!strcmp(disassembler, "objdump"))
+			break;
+		case PERF_DISASM_OBJDUMP:
 			err = symbol__disassemble_objdump(symfs_filename, sym, args);
-		else
-			pr_debug("Unknown disassembler %s, skipping...\n", disassembler);
-	}
-
-	if (err == 0) {
-		pr_debug("Disassembled with %s\nannotate.disassemblers=%s\n",
-			 disassembler, options->disassemblers_str);
+			break;
+		case PERF_DISASM_UNKNOWN: /* End of disassemblers. */
+		default:
+			goto out_remove_tmp;
+		}
+		if (err == 0)
+			pr_debug("Disassembled with %s\n", perf_disassembler__strs[dis]);
 	}
 out_remove_tmp:
 	if (decomp)