From: Maxim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: tarantool-patches@dev.tarantool.org, imun@tarantool.org, skaplun@tarantool.org Subject: [Tarantool-patches] [PATCH luajit v4 1/2] memprof: extend symtab with C-symbols Date: Sat, 30 Oct 2021 16:25:24 +0300 [thread overview] Message-ID: <6759290ff3f50f8a819d940b30c8903c9cd8883c.1635600120.git.m.kokryashkin@tarantool.org> (raw) In-Reply-To: <cover.1635600120.git.m.kokryashkin@tarantool.org> 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 | 159 ++++++++++++++++++++++++++++++++++++++++++++--- src/lj_memprof.h | 17 +++-- 2 files changed, 165 insertions(+), 11 deletions(-) diff --git a/src/lj_memprof.c b/src/lj_memprof.c index 2c1ef3b8..30c9697c 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 +30,123 @@ 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) +struct ghashtab_header { + uint32_t nbuckets; + uint32_t symoffset; + uint32_t bloom_size; + uint32_t bloom_shift; +}; + +uint32_t ghashtab_size(ElfW(Addr) ghashtab) +{ + /* + * There is no easy way to get count of symbols in GNU hashtable, so the + * only way to do this is to iterate over it. + */ + uint32_t last_entry = 0; + uint32_t *cur_bucket = NULL; + uint32_t *entry = NULL; + + const void *chain_address = NULL; + struct ghashtab_header *header = (struct ghashtab_header*)ghashtab; + const void *buckets = (void*)ghashtab + sizeof(struct 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 +171,17 @@ static void dump_symtab(struct lj_wbuf *out, const struct global_State *g) iter = &o->gch.nextgc; } + /* Write symbols. */ + struct symbol_resolver_conf conf = { + out, + SYMTAB_CFUNC, + 0, + *lib_cnt, + 0, + lib_cnt + }; + dl_iterate_phdr(resolve_symbolnames, &conf); + lj_wbuf_addbyte(out, SYMTAB_FINAL); } @@ -78,6 +211,7 @@ 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 +239,26 @@ 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 = { + out, + AEVENT_SYMTAB | ASOURCE_CFUNC, + 0, + *lib_cnt, + 0, + 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 +271,7 @@ 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 +284,9 @@ 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 +394,7 @@ 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
next prev parent reply other threads:[~2021-10-30 13:26 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-10-30 13:25 [Tarantool-patches] [PATCH luajit v4 0/2] memprof: add demangling capabilities for C functions Maxim Kokryashkin via Tarantool-patches 2021-10-30 13:25 ` Maxim Kokryashkin via Tarantool-patches [this message] 2021-12-21 14:38 ` [Tarantool-patches] [PATCH luajit v4 1/2] memprof: extend symtab with C-symbols Sergey Kaplun via Tarantool-patches 2021-10-30 13:25 ` [Tarantool-patches] [PATCH luajit v4 2/2] memprof: update memprof parser Maxim Kokryashkin via Tarantool-patches
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