This commit enriches memprof's symbol table and event stream with
information about C-symbols. That information will provide demangling
capabilities to the parser.
The following data is stored in symtab for each symbol:
| SYMTAB_CFUNC | symbol address | symbol name |
1 byte 8 bytes
magic
number
The following data is stored in event for each newly loaded symbol:
| (AEVENT_SYMTAB | ASOURCE_CFUNC) | symbol address | symbol name |
1 byte 8 bytes
magic
number
Part of tarantool/tarantool#5813
---
src/lj_memprof.c | 154 ++++++++++++++++++++++++++++++++++++++++++++---
src/lj_memprof.h | 17 ++++--
2 files changed, 160 insertions(+), 11 deletions(-)
diff --git a/src/lj_memprof.c b/src/lj_memprof.c
index 2c1ef3b8..17f97cc9 100644
--- a/src/lj_memprof.c
+++ b/src/lj_memprof.c
@@ -5,10 +5,16 @@
** Copyright (C) 2015-2019 IPONWEB Ltd.
*/
+#define _GNU_SOURCE
+#include <elf.h>
+
#define lj_memprof_c
#define LUA_CORE
#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <link.h>
#include "lj_arch.h"
#include "lj_memprof.h"
@@ -24,7 +30,118 @@
static const unsigned char ljs_header[] = {'l', 'j', 's', LJS_CURRENT_VERSION,
0x0, 0x0, 0x0};
-static void dump_symtab(struct lj_wbuf *out, const struct global_State *g)
+typedef struct {
+ uint32_t nbuckets;
+ uint32_t symoffset;
+ uint32_t bloom_size;
+ uint32_t bloom_shift;
+} ghashtab_header;
+
+uint32_t ghashtab_size(ElfW(Addr) ghashtab)
+{
+ uint32_t last_entry = 0;
+ uint32_t* cur_bucket = NULL;
+ uint32_t* entry = NULL;
+
+ const void* chain_address = NULL;
+ ghashtab_header* header = (ghashtab_header*)ghashtab;
+ const void* buckets = (void*)ghashtab + sizeof(ghashtab_header) + (sizeof(uint64_t) * header->bloom_size);
+
+ cur_bucket = (uint32_t*)buckets;
+ for (uint32_t i = 0; i < header->nbuckets; ++i) {
+ if (last_entry < *cur_bucket)
+ last_entry = *cur_bucket;
+ cur_bucket++;
+ }
+
+ if (last_entry < header->symoffset)
+ return header->symoffset;
+
+ chain_address = buckets + (sizeof(uint32_t) * header->nbuckets);
+ do {
+ entry = (uint32_t*)(chain_address + (last_entry - header->symoffset) * sizeof(uint32_t));
+ last_entry++;
+ } while (!(*entry & 1));
+
+ return last_entry;
+}
+
+struct symbol_resolver_conf {
+ struct lj_wbuf *buf;
+ const uint8_t header;
+
+ uint32_t cur_lib;
+ uint32_t lib_cnt_prev;
+ uint32_t to_dump_cnt;
+ uint32_t *lib_cnt;
+};
+
+int resolve_symbolnames(struct dl_phdr_info* info, size_t info_size, void* data)
+{
+ if(strcmp(info->dlpi_name, "linux-vdso.so.1") == 0) {
+ return 0;
+ }
+
+ ElfW(Dyn*) dyn = NULL;
+ ElfW(Sym*) sym = NULL;
+ ElfW(Word*) hashtab = NULL;
+ ElfW(Word) sym_cnt = 0;
+
+ char* strtab = 0;
+ char* sym_name = 0;
+
+ struct symbol_resolver_conf *conf = data;
+ const uint8_t header = conf->header;
+ struct lj_wbuf *buf = conf->buf;
+
+ conf->lib_cnt_prev = *conf->lib_cnt;
+ uint32_t lib_cnt_prev = conf->lib_cnt_prev;
+
+ if((conf->to_dump_cnt = info->dlpi_adds - lib_cnt_prev) == 0) {
+ /* No new libraries, stop resolver. */
+ return 1;
+ }
+
+ uint32_t lib_cnt = info->dlpi_adds - info->dlpi_subs;
+ if(conf->cur_lib < lib_cnt - conf->to_dump_cnt) {
+ /* That lib is already dumped, skip it. */
+ ++conf->cur_lib;
+ return 0;
+ }
+
+ for (size_t header_index = 0; header_index < info->dlpi_phnum; ++header_index) {
+ if (info->dlpi_phdr[header_index].p_type == PT_DYNAMIC) {
+ dyn = (ElfW(Dyn)*)(info->dlpi_addr + info->dlpi_phdr[header_index].p_vaddr);
+
+ while(dyn->d_tag != DT_NULL) {
+ if (dyn->d_tag == DT_HASH) {
+ hashtab = (ElfW(Word*))dyn->d_un.d_ptr;
+ sym_cnt = hashtab[1];
+ }
+ else if (dyn->d_tag == DT_GNU_HASH && sym_cnt == 0)
+ sym_cnt = ghashtab_size(dyn->d_un.d_ptr);
+ else if (dyn->d_tag == DT_STRTAB)
+ strtab = (char*)dyn->d_un.d_ptr;
+ else if (dyn->d_tag == DT_SYMTAB) {
+ sym = (ElfW(Sym*))dyn->d_un.d_ptr;
+
+ for (ElfW(Word) sym_index = 0; sym_index < sym_cnt; sym_index++) {
+ sym_name = &strtab[sym[sym_index].st_name];
+ lj_wbuf_addbyte(buf, header);
+ lj_wbuf_addu64(buf, sym[sym_index].st_value + info->dlpi_addr);
+ lj_wbuf_addstring(buf, sym_name);
+ }
+ }
+ dyn++;
+ }
+ }
+ }
+
+ ++conf->cur_lib;
+ return 0;
+}
+
+static void dump_symtab(struct lj_wbuf *out, const struct global_State *g, uint32_t *lib_cnt)
{
const GCRef *iter = &g->gc.root;
const GCobj *o;
@@ -49,6 +166,17 @@ static void dump_symtab(struct lj_wbuf *out, const struct global_State *g)
iter = &o->gch.nextgc;
}
+ /* Write symbols. */
+ struct symbol_resolver_conf conf = {
+ /* buf: */ out,
+ /* header: */ SYMTAB_CFUNC,
+ /* cur_lib: */ 0,
+ /* lib_cnt_prev: */ *lib_cnt,
+ /* to_dump_cnt: */ 0,
+ /* lib_cnt: */ lib_cnt
+ };
+ dl_iterate_phdr(resolve_symbolnames, &conf);
+
lj_wbuf_addbyte(out, SYMTAB_FINAL);
}
@@ -78,6 +206,7 @@ struct memprof {
struct alloc orig_alloc; /* Original allocator. */
struct lj_memprof_options opt; /* Profiling options. */
int saved_errno; /* Saved errno when profiler deinstrumented. */
+ uint32_t lib_cnt; /* Number of currently loaded libs. */
};
static struct memprof memprof = {0};
@@ -105,15 +234,26 @@ static void memprof_write_lfunc(struct lj_wbuf *out, uint8_t aevent,
}
static void memprof_write_cfunc(struct lj_wbuf *out, uint8_t aevent,
- const GCfunc *fn)
+ const GCfunc *fn, uint32_t *lib_cnt)
{
+ /* Check if there are any new libs. */
+ struct symbol_resolver_conf conf = {
+ /* buf: */ out,
+ /* header: */ AEVENT_SYMTAB | ASOURCE_CFUNC,
+ /* cur_lib: */ 0,
+ /* lib_cnt_prev: */ *lib_cnt,
+ /* to_dump_cnt: */ 0,
+ /* lib_cnt: */ lib_cnt
+ };
+ dl_iterate_phdr(resolve_symbolnames, &conf);
+
lj_wbuf_addbyte(out, aevent | ASOURCE_CFUNC);
lj_wbuf_addu64(out, (uintptr_t)fn->c.f);
}
static void memprof_write_ffunc(struct lj_wbuf *out, uint8_t aevent,
GCfunc *fn, struct lua_State *L,
- cTValue *frame)
+ cTValue *frame, uint32_t *lib_cnt)
{
cTValue *pframe = frame_prev(frame);
GCfunc *pfn = frame_func(pframe);
@@ -126,7 +266,7 @@ static void memprof_write_ffunc(struct lj_wbuf *out, uint8_t aevent,
if (pfn != NULL && isluafunc(pfn))
memprof_write_lfunc(out, aevent, pfn, L, frame);
else
- memprof_write_cfunc(out, aevent, fn);
+ memprof_write_cfunc(out, aevent, fn, lib_cnt);
}
static void memprof_write_func(struct memprof *mp, uint8_t aevent)
@@ -139,9 +279,9 @@ static void memprof_write_func(struct memprof *mp, uint8_t aevent)
if (isluafunc(fn))
memprof_write_lfunc(out, aevent, fn, L, NULL);
else if (isffunc(fn))
- memprof_write_ffunc(out, aevent, fn, L, frame);
+ memprof_write_ffunc(out, aevent, fn, L, frame, &mp->lib_cnt);
else if (iscfunc(fn))
- memprof_write_cfunc(out, aevent, fn);
+ memprof_write_cfunc(out, aevent, fn, &mp->lib_cnt);
else
lua_assert(0);
}
@@ -249,7 +389,7 @@ int lj_memprof_start(struct lua_State *L, const struct lj_memprof_options *opt)
/* Init output. */
lj_wbuf_init(&mp->out, mp_opt->writer, mp_opt->ctx, mp_opt->buf, mp_opt->len);
- dump_symtab(&mp->out, mp->g);
+ dump_symtab(&mp->out, mp->g, &mp->lib_cnt);
/* Write prologue. */
lj_wbuf_addn(&mp->out, ljm_header, ljm_header_len);
diff --git a/src/lj_memprof.h b/src/lj_memprof.h
index 3417475d..337fa76a 100644
--- a/src/lj_memprof.h
+++ b/src/lj_memprof.h
@@ -16,7 +16,7 @@
#include "lj_def.h"
#include "lj_wbuf.h"
-#define LJS_CURRENT_VERSION 0x1
+#define LJS_CURRENT_VERSION 0x2
/*
** symtab format:
@@ -25,12 +25,14 @@
** prologue := 'l' 'j' 's' version reserved
** version := <BYTE>
** reserved := <BYTE> <BYTE> <BYTE>
-** sym := sym-lua | sym-final
+** sym := sym-lua | sym-cfunc | sym-final
** sym-lua := sym-header sym-addr sym-chunk sym-line
** sym-header := <BYTE>
** sym-addr := <ULEB128>
** sym-chunk := string
** sym-line := <ULEB128>
+** sym-cfunc := sym-header sym-addr sym-name
+** sym-name := string
** sym-final := sym-header
** string := string-len string-payload
** string-len := <ULEB128>
@@ -51,9 +53,10 @@
*/
#define SYMTAB_LFUNC ((uint8_t)0)
+#define SYMTAB_CFUNC ((uint8_t)1)
#define SYMTAB_FINAL ((uint8_t)0x80)
-#define LJM_CURRENT_FORMAT_VERSION 0x01
+#define LJM_CURRENT_FORMAT_VERSION 0x02
/*
** Event stream format:
@@ -64,10 +67,11 @@
** prologue := 'l' 'j' 'm' version reserved
** version := <BYTE>
** reserved := <BYTE> <BYTE> <BYTE>
-** event := event-alloc | event-realloc | event-free
+** event := event-alloc | event-realloc | event-free | event-symtab
** event-alloc := event-header loc? naddr nsize
** event-realloc := event-header loc? oaddr osize naddr nsize
** event-free := event-header loc? oaddr osize
+** event-symtab := event-header sym-addr sym-name
** event-header := <BYTE>
** loc := loc-lua | loc-c
** loc-lua := sym-addr line-no
@@ -78,7 +82,11 @@
** naddr := <ULEB128>
** osize := <ULEB128>
** nsize := <ULEB128>
+** sym-name := string
** epilogue := event-header
+** string := string-len string-payload
+** string-len := <ULEB128>
+** string-payload := <BYTE> {string-len}
**
** <BYTE> : A single byte (no surprises here)
** <ULEB128>: Unsigned integer represented in ULEB128 encoding
@@ -97,6 +105,7 @@
*/
/* Allocation events. */
+#define AEVENT_SYMTAB ((uint8_t)0)
#define AEVENT_ALLOC ((uint8_t)1)
#define AEVENT_FREE ((uint8_t)2)
#define AEVENT_REALLOC ((uint8_t)(AEVENT_ALLOC | AEVENT_FREE))
--
2.33.0