perf llvm: Move llvm functionality into its own file

LLVM disassembly support was in disasm.c and addr2line support in
srcline.c. Move support out of these files into llvm.[ch] and remove
LLVM includes from those files. As disassembly routines can fail, make
failure the only option without HAVE_LIBLLVM_SUPPORT. For simplicity's
sake, duplicate the read_symbol utility function.

The intent with moving LLVM support into a single file is that dynamic
support, using dlopen for libllvm, can be added in later patches. This
can potentially always succeed or fail, so relying on ifdefs isn't
sufficient. Using dlopen is a useful option to minimize the perf tools
dependencies and potentially size.

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: Mark Rutland <mark.rutland@arm.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>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 326 insertions, 0 deletions

diff --git a/tools/perf/util/llvm.c b/tools/perf/util/llvm.c
new file mode 100644
index 000000000000..ddc737194692
--- /dev/null
+++ b/tools/perf/util/llvm.c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "llvm.h"
+#include "annotate.h"
+#include "debug.h"
+#include "dso.h"
+#include "map.h"
+#include "namespaces.h"
+#include "srcline.h"
+#include "symbol.h"
+#include <fcntl.h>
+#include <unistd.h>
+#include <linux/zalloc.h>
+
+#ifdef HAVE_LIBLLVM_SUPPORT
+#include "llvm-c-helpers.h"
+#include <llvm-c/Disassembler.h>
+#include <llvm-c/Target.h>
+#endif
+
+#ifdef HAVE_LIBLLVM_SUPPORT
+static void free_llvm_inline_frames(struct llvm_a2l_frame *inline_frames,
+				    int num_frames)
+{
+	if (inline_frames != NULL) {
+		for (int i = 0; i < num_frames; ++i) {
+			zfree(&inline_frames[i].filename);
+			zfree(&inline_frames[i].funcname);
+		}
+		zfree(&inline_frames);
+	}
+}
+#endif
+
+int llvm__addr2line(const char *dso_name __maybe_unused, u64 addr __maybe_unused,
+		     char **file __maybe_unused, unsigned int *line __maybe_unused,
+		     struct dso *dso __maybe_unused, bool unwind_inlines __maybe_unused,
+		     struct inline_node *node __maybe_unused, struct symbol *sym __maybe_unused)
+{
+#ifdef HAVE_LIBLLVM_SUPPORT
+	struct llvm_a2l_frame *inline_frames = NULL;
+	int num_frames = llvm_addr2line(dso_name, addr, file, line,
+					node && unwind_inlines, &inline_frames);
+
+	if (num_frames == 0 || !inline_frames) {
+		/* Error, or we didn't want inlines. */
+		return num_frames;
+	}
+
+	for (int i = 0; i < num_frames; ++i) {
+		struct symbol *inline_sym =
+			new_inline_sym(dso, sym, inline_frames[i].funcname);
+		char *srcline = NULL;
+
+		if (inline_frames[i].filename) {
+			srcline =
+				srcline_from_fileline(inline_frames[i].filename,
+						      inline_frames[i].line);
+		}
+		if (inline_list__append(inline_sym, srcline, node) != 0) {
+			free_llvm_inline_frames(inline_frames, num_frames);
+			return 0;
+		}
+	}
+	free_llvm_inline_frames(inline_frames, num_frames);
+
+	return num_frames;
+#else
+	return -1;
+#endif
+}
+
+void dso__free_a2l_llvm(struct dso *dso __maybe_unused)
+{
+	/* Nothing to free. */
+}
+
+
+#if defined(HAVE_LIBLLVM_SUPPORT)
+struct find_file_offset_data {
+	u64 ip;
+	u64 offset;
+};
+
+/* This will be called for each PHDR in an ELF binary */
+static int find_file_offset(u64 start, u64 len, u64 pgoff, void *arg)
+{
+	struct find_file_offset_data *data = arg;
+
+	if (start <= data->ip && data->ip < start + len) {
+		data->offset = pgoff + data->ip - start;
+		return 1;
+	}
+	return 0;
+}
+
+static u8 *
+read_symbol(const char *filename, struct map *map, struct symbol *sym,
+	    u64 *len, bool *is_64bit)
+{
+	struct dso *dso = map__dso(map);
+	struct nscookie nsc;
+	u64 start = map__rip_2objdump(map, sym->start);
+	u64 end = map__rip_2objdump(map, sym->end);
+	int fd, count;
+	u8 *buf = NULL;
+	struct find_file_offset_data data = {
+		.ip = start,
+	};
+
+	*is_64bit = false;
+
+	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
+	fd = open(filename, O_RDONLY);
+	nsinfo__mountns_exit(&nsc);
+	if (fd < 0)
+		return NULL;
+
+	if (file__read_maps(fd, /*exe=*/true, find_file_offset, &data,
+			    is_64bit) == 0)
+		goto err;
+
+	*len = end - start;
+	buf = malloc(*len);
+	if (buf == NULL)
+		goto err;
+
+	count = pread(fd, buf, *len, data.offset);
+	close(fd);
+	fd = -1;
+
+	if ((u64)count != *len)
+		goto err;
+
+	return buf;
+
+err:
+	if (fd >= 0)
+		close(fd);
+	free(buf);
+	return NULL;
+}
+#endif
+
+/*
+ * Whenever LLVM wants to resolve an address into a symbol, it calls this
+ * callback. We don't ever actually _return_ anything (in particular, because
+ * it puts quotation marks around what we return), but we use this as a hint
+ * that there is a branch or PC-relative address in the expression that we
+ * should add some textual annotation for after the instruction. The caller
+ * will use this information to add the actual annotation.
+ */
+#ifdef HAVE_LIBLLVM_SUPPORT
+struct symbol_lookup_storage {
+	u64 branch_addr;
+	u64 pcrel_load_addr;
+};
+
+static const char *
+symbol_lookup_callback(void *disinfo, uint64_t value,
+		       uint64_t *ref_type,
+		       uint64_t address __maybe_unused,
+		       const char **ref __maybe_unused)
+{
+	struct symbol_lookup_storage *storage = disinfo;
+
+	if (*ref_type == LLVMDisassembler_ReferenceType_In_Branch)
+		storage->branch_addr = value;
+	else if (*ref_type == LLVMDisassembler_ReferenceType_In_PCrel_Load)
+		storage->pcrel_load_addr = value;
+	*ref_type = LLVMDisassembler_ReferenceType_InOut_None;
+	return NULL;
+}
+#endif
+
+int symbol__disassemble_llvm(const char *filename, struct symbol *sym,
+			     struct annotate_args *args __maybe_unused)
+{
+#ifdef HAVE_LIBLLVM_SUPPORT
+	struct annotation *notes = symbol__annotation(sym);
+	struct map *map = args->ms.map;
+	struct dso *dso = map__dso(map);
+	u64 start = map__rip_2objdump(map, sym->start);
+	u8 *buf;
+	u64 len;
+	u64 pc;
+	bool is_64bit;
+	char triplet[64];
+	char disasm_buf[2048];
+	size_t disasm_len;
+	struct disasm_line *dl;
+	LLVMDisasmContextRef disasm = NULL;
+	struct symbol_lookup_storage storage;
+	char *line_storage = NULL;
+	size_t line_storage_len = 0;
+	int ret = -1;
+
+	if (args->options->objdump_path)
+		return -1;
+
+	LLVMInitializeAllTargetInfos();
+	LLVMInitializeAllTargetMCs();
+	LLVMInitializeAllDisassemblers();
+
+	buf = read_symbol(filename, map, sym, &len, &is_64bit);
+	if (buf == NULL)
+		return -1;
+
+	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");
+	} else {
+		scnprintf(triplet, sizeof(triplet), "%s-linux-gnu",
+			  args->arch->name);
+	}
+
+	disasm = LLVMCreateDisasm(triplet, &storage, 0, NULL,
+				  symbol_lookup_callback);
+	if (disasm == NULL)
+		goto err;
+
+	if (args->options->disassembler_style &&
+	    !strcmp(args->options->disassembler_style, "intel"))
+		LLVMSetDisasmOptions(disasm,
+				     LLVMDisassembler_Option_AsmPrinterVariant);
+
+	/*
+	 * This needs to be set after AsmPrinterVariant, due to a bug in LLVM;
+	 * setting AsmPrinterVariant makes a new instruction printer, making it
+	 * forget about the PrintImmHex flag (which is applied before if both
+	 * are given to the same call).
+	 */
+	LLVMSetDisasmOptions(disasm, LLVMDisassembler_Option_PrintImmHex);
+
+	/* add the function address and name */
+	scnprintf(disasm_buf, sizeof(disasm_buf), "%#"PRIx64" <%s>:",
+		  start, sym->name);
+
+	args->offset = -1;
+	args->line = disasm_buf;
+	args->line_nr = 0;
+	args->fileloc = NULL;
+	args->ms.sym = sym;
+
+	dl = disasm_line__new(args);
+	if (dl == NULL)
+		goto err;
+
+	annotation_line__add(&dl->al, &notes->src->source);
+
+	pc = start;
+	for (u64 offset = 0; offset < len; ) {
+		unsigned int ins_len;
+
+		storage.branch_addr = 0;
+		storage.pcrel_load_addr = 0;
+
+		ins_len = LLVMDisasmInstruction(disasm, buf + offset,
+						len - offset, pc,
+						disasm_buf, sizeof(disasm_buf));
+		if (ins_len == 0)
+			goto err;
+		disasm_len = strlen(disasm_buf);
+
+		if (storage.branch_addr != 0) {
+			char *name = llvm_name_for_code(dso, filename,
+							storage.branch_addr);
+			if (name != NULL) {
+				disasm_len += scnprintf(disasm_buf + disasm_len,
+							sizeof(disasm_buf) -
+								disasm_len,
+							" <%s>", name);
+				free(name);
+			}
+		}
+		if (storage.pcrel_load_addr != 0) {
+			char *name = llvm_name_for_data(dso, filename,
+							storage.pcrel_load_addr);
+			disasm_len += scnprintf(disasm_buf + disasm_len,
+						sizeof(disasm_buf) - disasm_len,
+						"  # %#"PRIx64,
+						storage.pcrel_load_addr);
+			if (name) {
+				disasm_len += scnprintf(disasm_buf + disasm_len,
+							sizeof(disasm_buf) -
+							disasm_len,
+							" <%s>", name);
+				free(name);
+			}
+		}
+
+		args->offset = offset;
+		args->line = expand_tabs(disasm_buf, &line_storage,
+					 &line_storage_len);
+		args->line_nr = 0;
+		args->fileloc = NULL;
+		args->ms.sym = sym;
+
+		llvm_addr2line(filename, pc, &args->fileloc,
+			       (unsigned int *)&args->line_nr, false, NULL);
+
+		dl = disasm_line__new(args);
+		if (dl == NULL)
+			goto err;
+
+		annotation_line__add(&dl->al, &notes->src->source);
+
+		free(args->fileloc);
+		pc += ins_len;
+		offset += ins_len;
+	}
+
+	ret = 0;
+
+err:
+	LLVMDisasmDispose(disasm);
+	free(buf);
+	free(line_storage);
+	return ret;
+#else // HAVE_LIBLLVM_SUPPORT
+	pr_debug("The LLVM disassembler isn't linked in for %s in %s\n",
+		 sym->name, filename);
+	return -1;
+#endif
+}