From: Ian Rogers <irogers@google.com>
Date: Sun, 5 Oct 2025 21:22:03 +0000 (-0700)
Subject: perf llvm: Reduce LLVM initialization
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0e52f3f9f15fdf914247f514f46d14b4fa4b2cbb;p=users%2Fhch%2Fmisc.git

perf llvm: Reduce LLVM initialization

Move the 3 LLVM initialization routines to be called in a single
init_llvm function that has its own bool to avoid repeated
initialization.

Reduce the scope of triplet and avoid copying strings for x86.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Charlie Jenkins <charlie@rivosinc.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Haibo Xu <haibo1.xu@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
[ Move init_llvm() under HAVE_LIBLLVM_SUPPORT to fix the build ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/util/llvm.c b/tools/perf/util/llvm.c
index ddc737194692..b71649d616e3 100644
--- a/tools/perf/util/llvm.c
+++ b/tools/perf/util/llvm.c
@@ -74,8 +74,19 @@ void dso__free_a2l_llvm(struct dso *dso __maybe_unused)
 	/* Nothing to free. */
 }
 
+#ifdef HAVE_LIBLLVM_SUPPORT
+static void init_llvm(void)
+{
+	static bool init;
+
+	if (!init) {
+		LLVMInitializeAllTargetInfos();
+		LLVMInitializeAllTargetMCs();
+		LLVMInitializeAllDisassemblers();
+		init = true;
+	}
+}
 
-#if defined(HAVE_LIBLLVM_SUPPORT)
 struct find_file_offset_data {
 	u64 ip;
 	u64 offset;
@@ -184,7 +195,6 @@ int symbol__disassemble_llvm(const char *filename, struct symbol *sym,
 	u64 len;
 	u64 pc;
 	bool is_64bit;
-	char triplet[64];
 	char disasm_buf[2048];
 	size_t disasm_len;
 	struct disasm_line *dl;
@@ -197,26 +207,25 @@ int symbol__disassemble_llvm(const char *filename, struct symbol *sym,
 	if (args->options->objdump_path)
 		return -1;
 
-	LLVMInitializeAllTargetInfos();
-	LLVMInitializeAllTargetMCs();
-	LLVMInitializeAllDisassemblers();
-
 	buf = read_symbol(filename, map, sym, &len, &is_64bit);
 	if (buf == NULL)
 		return -1;
 
+	init_llvm();
 	if (arch__is(args->arch, "x86")) {
-		if (is_64bit)
-			scnprintf(triplet, sizeof(triplet), "x86_64-pc-linux");
-		else
-			scnprintf(triplet, sizeof(triplet), "i686-pc-linux");
+		const char *triplet = is_64bit ? "x86_64-pc-linux" : "i686-pc-linux";
+
+		disasm = LLVMCreateDisasm(triplet, &storage, /*tag_type=*/0,
+					  /*get_op_info=*/NULL, symbol_lookup_callback);
 	} else {
+		char triplet[64];
+
 		scnprintf(triplet, sizeof(triplet), "%s-linux-gnu",
 			  args->arch->name);
+		disasm = LLVMCreateDisasm(triplet, &storage, /*tag_type=*/0,
+					  /*get_op_info=*/NULL, symbol_lookup_callback);
 	}
 
-	disasm = LLVMCreateDisasm(triplet, &storage, 0, NULL,
-				  symbol_lookup_callback);
 	if (disasm == NULL)
 		goto err;