[PATCH v2 5/5] perf annotate: Add symbol name when using capstone

Namhyung Kim
2024-03-29T21:58:16Z

This is to keep the existing behavior with objdump. It needs to show
symbol information of global variables like below:

Percent | Source code & Disassembly of elf for cycles:P (1 samples, percent: local period)
------------------------------------------------------------------------------------------------
: 0 0xffffffff81338f70 <vm_normal_page>:
0.00 : ffffffff81338f70: endbr64
0.00 : ffffffff81338f74: callq 0xffffffff81083a40
0.00 : ffffffff81338f79: movq %rdi, %r8
0.00 : ffffffff81338f7c: movq %rdx, %rdi
0.00 : ffffffff81338f7f: callq *0x17021c3(%rip) # ffffffff82a3b148 <pv_ops+0x1e8>
0.00 : ffffffff81338f85: movq 0xffbf3c(%rip), %rdx # ffffffff82334ec8 <physical_mask>
0.00 : ffffffff81338f8c: testq %rax, %rax ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
0.00 : ffffffff81338f8f: je 0xffffffff81338fd0 here
0.00 : ffffffff81338f91: movq %rax, %rcx
0.00 : ffffffff81338f94: andl $1, %ecx

Cc: Changbin Du <changbin.du@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/util/disasm.c | 74 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 71 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index cd2f7d67f423..1148153ea94f 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -1363,6 +1363,12 @@ static int open_capstone_handle(struct annotate_args *args, bool is_64bit,
!strcmp(opt->disassembler_style, "att"))
cs_option(*handle, CS_OPT_SYNTAX, CS_OPT_SYNTAX_ATT);

+ /*
+ * Resolving address operands to symbols is implemented
+ * on x86 by investigating instruction details.
+ */
+ cs_option(*handle, CS_OPT_DETAIL, CS_OPT_ON);
+
return 0;
}

@@ -1383,6 +1389,63 @@ static int find_file_offset(u64 start, u64 len, u64 pgoff, void *arg)
return 0;
}

+static void print_capstone_detail(cs_insn *insn, char *buf, size_t len,
+ struct annotate_args *args, u64 addr)
+{
+ int i;
+ struct map *map = args->ms.map;
+ struct symbol *sym;
+
+ /* TODO: support more architectures */
+ if (!arch__is(args->arch, "x86"))
+ return;
+
+ if (insn->detail == NULL)
+ return;
+
+ for (i = 0; i < insn->detail->x86.op_count; i++) {
+ cs_x86_op *op = &insn->detail->x86.operands[i];
+ u64 orig_addr;
+
+ if (op->type != X86_OP_MEM)
+ continue;
+
+ /* only print RIP-based global symbols for now */
+ if (op->mem.base != X86_REG_RIP)
+ continue;
+
+ /* get the target address */
+ orig_addr = addr + insn->size + op->mem.disp;
+ addr = map__objdump_2mem(map, orig_addr);
+
+ if (map__dso(map)->kernel) {
+ /*
+ * The kernel maps can be splitted into sections,
+ * let's find the map first and the search the symbol.
+ */
+ map = maps__find(map__kmaps(map), addr);
+ if (map == NULL)
+ continue;
+ }
+
+ /* convert it to map-relative address for search */
+ addr = map__map_ip(map, addr);
+
+ sym = map__find_symbol(map, addr);
+ if (sym == NULL)
+ continue;
+
+ if (addr == sym->start) {
+ scnprintf(buf, len, "\t# %"PRIx64" <%s>",
+ orig_addr, sym->name);
+ } else {
+ scnprintf(buf, len, "\t# %"PRIx64" <%s+%#"PRIx64">",
+ orig_addr, sym->name, addr - sym->start);
+ }
+ break;
+ }
+}
+
static int symbol__disassemble_capstone(char *filename, struct symbol *sym,
struct annotate_args *args)
{
@@ -1453,9 +1516,14 @@ static int symbol__disassemble_capstone(char *filename, struct symbol *sym,

count = cs_disasm(handle, buf, len, start, len, &insn);
for (i = 0, offset = 0; i < count; i++) {
- scnprintf(disasm_buf, sizeof(disasm_buf),
- " %-7s %s",
- insn[i].mnemonic, insn[i].op_str);
+ int printed;
+
+ printed = scnprintf(disasm_buf, sizeof(disasm_buf),
+ " %-7s %s",
+ insn[i].mnemonic, insn[i].op_str);
+ print_capstone_detail(&insn[i], disasm_buf + printed,
+ sizeof(disasm_buf) - printed, args,
+ start + offset);

args->offset = offset;
args->line = disasm_buf;
--
2.44.0.478.gd926399ef9-goog