[v7,04/18] gendwarfksyms: Add a cache for processed DIEs

Message ID	20241219210736.2990838-24-samitolvanen@google.com (mailing list archive)
State	New
Headers	show Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EDF691D6DD4 for <linux-kbuild@vger.kernel.org>; Thu, 19 Dec 2024 21:07:57 +0000 (UTC) Date: Thu, 19 Dec 2024 21:07:41 +0000 In-Reply-To: <20241219210736.2990838-20-samitolvanen@google.com> Precedence: bulk Mime-Version: 1.0 References: <20241219210736.2990838-20-samitolvanen@google.com> Message-ID: <20241219210736.2990838-24-samitolvanen@google.com> Subject: [PATCH v7 04/18] gendwarfksyms: Add a cache for processed DIEs From: Sami Tolvanen <samitolvanen@google.com> To: Masahiro Yamada <masahiroy@kernel.org>, Luis Chamberlain <mcgrof@kernel.org>, Miguel Ojeda <ojeda@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Matthew Maurer <mmaurer@google.com>, Alex Gaynor <alex.gaynor@gmail.com>, Gary Guo <gary@garyguo.net>, Petr Pavlu <petr.pavlu@suse.com>, Daniel Gomez <da.gomez@samsung.com>, Neal Gompa <neal@gompa.dev>, Hector Martin <marcan@marcan.st>, Janne Grunau <j@jannau.net>, Miroslav Benes <mbenes@suse.cz>, Asahi Linux <asahi@lists.linux.dev>, Sedat Dilek <sedat.dilek@gmail.com>, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, rust-for-linux@vger.kernel.org, Sami Tolvanen <samitolvanen@google.com> Content-Type: text/plain; charset="UTF-8"
Series	Implement DWARF modversions \| expand [v7,00/18] Implement DWARF modversions [v7,01/18] tools: Add gendwarfksyms [v7,02/18] gendwarfksyms: Add address matching [v7,03/18] gendwarfksyms: Expand base_type [v7,04/18] gendwarfksyms: Add a cache for processed DIEs [v7,05/18] gendwarfksyms: Expand type modifiers and typedefs [v7,06/18] gendwarfksyms: Expand subroutine_type [v7,07/18] gendwarfksyms: Expand array_type [v7,08/18] gendwarfksyms: Expand structure types [v7,09/18] gendwarfksyms: Limit structure expansion [v7,10/18] gendwarfksyms: Add die_map debugging [v7,11/18] gendwarfksyms: Add symtypes output [v7,12/18] gendwarfksyms: Add symbol versioning [v7,13/18] gendwarfksyms: Add support for kABI rules [v7,14/18] gendwarfksyms: Add support for reserved and ignored fields [v7,15/18] gendwarfksyms: Add support for symbol type pointers [v7,16/18] export: Add __gendwarfksyms_ptr_ references to exported symbols [v7,17/18] kbuild: Add gendwarfksyms as an alternative to genksyms [v7,18/18] Documentation/kbuild: Add DWARF module versioning

diff --git a/scripts/gendwarfksyms/Makefile b/scripts/gendwarfksyms/Makefile index 9f8fec4fd39b..c0d4ce50fc27 100644 --- a/scripts/gendwarfksyms/Makefile +++ b/scripts/gendwarfksyms/Makefile @@ -2,6 +2,7 @@ hostprogs-always-y += gendwarfksyms gendwarfksyms-objs += gendwarfksyms.o +gendwarfksyms-objs += die.o gendwarfksyms-objs += dwarf.o gendwarfksyms-objs += symbols.o diff --git a/scripts/gendwarfksyms/die.c b/scripts/gendwarfksyms/die.c new file mode 100644 index 000000000000..b7d900c6a9c8 --- /dev/null +++ b/scripts/gendwarfksyms/die.c @@ -0,0 +1,143 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2024 Google LLC + */ + +#include <string.h> +#include "gendwarfksyms.h" + +#define DIE_HASH_BITS 15 + +/* {die->addr, state} -> struct die * */ +static HASHTABLE_DEFINE(die_map, 1 << DIE_HASH_BITS); + +static unsigned int map_hits; +static unsigned int map_misses; + +static inline unsigned int die_hash(uintptr_t addr, enum die_state state) +{ + return hash_32(addr_hash(addr) ^ (unsigned int)state); +} + +static void init_die(struct die *cd) +{ + cd->state = DIE_INCOMPLETE; + cd->fqn = NULL; + cd->tag = -1; + cd->addr = 0; + INIT_LIST_HEAD(&cd->fragments); +} + +static struct die *create_die(Dwarf_Die *die, enum die_state state) +{ + struct die *cd; + + cd = xmalloc(sizeof(struct die)); + init_die(cd); + cd->addr = (uintptr_t)die->addr; + + hash_add(die_map, &cd->hash, die_hash(cd->addr, state)); + return cd; +} + +int __die_map_get(uintptr_t addr, enum die_state state, struct die **res) +{ + struct die *cd; + + hash_for_each_possible(die_map, cd, hash, die_hash(addr, state)) { + if (cd->addr == addr && cd->state == state) { + *res = cd; + return 0; + } + } + + return -1; +} + +struct die *die_map_get(Dwarf_Die *die, enum die_state state) +{ + struct die *cd; + + if (__die_map_get((uintptr_t)die->addr, state, &cd) == 0) { + map_hits++; + return cd; + } + + map_misses++; + return create_die(die, state); +} + +static void reset_die(struct die *cd) +{ + struct die_fragment *tmp; + struct die_fragment *df; + + list_for_each_entry_safe(df, tmp, &cd->fragments, list) { + if (df->type == FRAGMENT_STRING) + free(df->data.str); + free(df); + } + + if (cd->fqn && *cd->fqn) + free(cd->fqn); + init_die(cd); +} + +void die_map_free(void) +{ + struct hlist_node *tmp; + unsigned int stats[DIE_LAST + 1]; + struct die *cd; + int i; + + memset(stats, 0, sizeof(stats)); + + hash_for_each_safe(die_map, cd, tmp, hash) { + stats[cd->state]++; + reset_die(cd); + free(cd); + } + hash_init(die_map); + + if (map_hits + map_misses > 0) + debug("hits %u, misses %u (hit rate %.02f%%)", map_hits, + map_misses, + (100.0f * map_hits) / (map_hits + map_misses)); + + for (i = 0; i <= DIE_LAST; i++) + debug("%s: %u entries", die_state_name(i), stats[i]); +} + +static struct die_fragment *append_item(struct die *cd) +{ + struct die_fragment *df; + + df = xmalloc(sizeof(struct die_fragment)); + df->type = FRAGMENT_EMPTY; + list_add_tail(&df->list, &cd->fragments); + return df; +} + +void die_map_add_string(struct die *cd, const char *str) +{ + struct die_fragment *df; + + if (!cd) + return; + + df = append_item(cd); + df->data.str = xstrdup(str); + df->type = FRAGMENT_STRING; +} + +void die_map_add_die(struct die *cd, struct die *child) +{ + struct die_fragment *df; + + if (!cd) + return; + + df = append_item(cd); + df->data.addr = child->addr; + df->type = FRAGMENT_DIE; +} diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c index 74e75b8ec891..f40e23a547da 100644 --- a/scripts/gendwarfksyms/dwarf.c +++ b/scripts/gendwarfksyms/dwarf.c @@ -72,17 +72,19 @@ static bool match_export_symbol(struct state *state, Dwarf_Die *die) /* * Type string processing */ -static void process(const char *s) +static void process(struct die *cache, const char *s) { s = s ?: "<null>"; if (dump_dies) fputs(s, stderr); + + die_map_add_string(cache, s); } #define MAX_FMT_BUFFER_SIZE 128 -static void process_fmt(const char *fmt, ...) +static void process_fmt(struct die *cache, const char *fmt, ...) { char buf[MAX_FMT_BUFFER_SIZE]; va_list args; @@ -92,7 +94,7 @@ static void process_fmt(const char *fmt, ...) if (checkp(vsnprintf(buf, sizeof(buf), fmt, args)) >= sizeof(buf)) error("vsnprintf overflow: increase MAX_FMT_BUFFER_SIZE"); - process(buf); + process(cache, buf); va_end(args); } @@ -165,18 +167,28 @@ static char *get_fqn(Dwarf_Die *die) return fqn; } -static void process_fqn(Dwarf_Die *die) +static void update_fqn(struct die *cache, Dwarf_Die *die) +{ + if (!cache->fqn) + cache->fqn = get_fqn(die) ?: ""; +} + +static void process_fqn(struct die *cache, Dwarf_Die *die) { - process(" "); - process(get_fqn(die) ?: ""); + update_fqn(cache, die); + if (*cache->fqn) + process(cache, " "); + process(cache, cache->fqn); } -#define DEFINE_PROCESS_UDATA_ATTRIBUTE(attribute) \ - static void process_##attribute##_attr(Dwarf_Die *die) \ - { \ - Dwarf_Word value; \ - if (get_udata_attr(die, DW_AT_##attribute, &value)) \ - process_fmt(" " #attribute "(%" PRIu64 ")", value); \ +#define DEFINE_PROCESS_UDATA_ATTRIBUTE(attribute) \ + static void process_##attribute##_attr(struct die *cache, \ + Dwarf_Die *die) \ + { \ + Dwarf_Word value; \ + if (get_udata_attr(die, DW_AT_##attribute, &value)) \ + process_fmt(cache, " " #attribute "(%" PRIu64 ")", \ + value); \ } DEFINE_PROCESS_UDATA_ATTRIBUTE(alignment) @@ -188,8 +200,9 @@ bool match_all(Dwarf_Die *die) return true; } -int process_die_container(struct state *state, Dwarf_Die *die, - die_callback_t func, die_match_callback_t match) +int process_die_container(struct state *state, struct die *cache, + Dwarf_Die *die, die_callback_t func, + die_match_callback_t match) { Dwarf_Die current; int res; @@ -198,7 +211,7 @@ int process_die_container(struct state *state, Dwarf_Die *die, while (!res) { if (match(&current)) { /* <0 = error, 0 = continue, >0 = stop */ - res = checkp(func(state, &current)); + res = checkp(func(state, cache, &current)); if (res) return res; } @@ -209,39 +222,78 @@ int process_die_container(struct state *state, Dwarf_Die *die, return 0; } -static int process_type(struct state *state, Dwarf_Die *die); +static int process_type(struct state *state, struct die *parent, + Dwarf_Die *die); -static void process_type_attr(struct state *state, Dwarf_Die *die) +static void process_type_attr(struct state *state, struct die *cache, + Dwarf_Die *die) { Dwarf_Die type; if (get_ref_die_attr(die, DW_AT_type, &type)) { - check(process_type(state, &type)); + check(process_type(state, cache, &type)); return; } /* Compilers can omit DW_AT_type -- print out 'void' to clarify */ - process("base_type void"); + process(cache, "base_type void"); +} + +static void process_base_type(struct state *state, struct die *cache, + Dwarf_Die *die) +{ + process(cache, "base_type"); + process_fqn(cache, die); + process_byte_size_attr(cache, die); + process_encoding_attr(cache, die); + process_alignment_attr(cache, die); } -static void process_base_type(struct state *state, Dwarf_Die *die) +static void process_cached(struct state *state, struct die *cache, + Dwarf_Die *die) { - process("base_type"); - process_fqn(die); - process_byte_size_attr(die); - process_encoding_attr(die); - process_alignment_attr(die); + struct die_fragment *df; + Dwarf_Die child; + + list_for_each_entry(df, &cache->fragments, list) { + switch (df->type) { + case FRAGMENT_STRING: + process(NULL, df->data.str); + break; + case FRAGMENT_DIE: + if (!dwarf_die_addr_die(dwarf_cu_getdwarf(die->cu), + (void *)df->data.addr, &child)) + error("dwarf_die_addr_die failed"); + check(process_type(state, NULL, &child)); + break; + default: + error("empty die_fragment"); + } + } } -#define PROCESS_TYPE(type) \ - case DW_TAG_##type##_type: \ - process_##type##_type(state, die); \ +#define PROCESS_TYPE(type) \ + case DW_TAG_##type##_type: \ + process_##type##_type(state, cache, die); \ break; -static int process_type(struct state *state, Dwarf_Die *die) +static int process_type(struct state *state, struct die *parent, Dwarf_Die *die) { + struct die *cache; int tag = dwarf_tag(die); + /* + * If we have the DIE already cached, use it instead of walking + * through DWARF. + */ + cache = die_map_get(die, DIE_COMPLETE); + + if (cache->state == DIE_COMPLETE) { + process_cached(state, cache, die); + die_map_add_die(parent, cache); + return 0; + } + switch (tag) { PROCESS_TYPE(base) default: @@ -249,6 +301,11 @@ static int process_type(struct state *state, Dwarf_Die *die) break; } + /* Update cache state and append to the parent (if any) */ + cache->tag = tag; + cache->state = DIE_COMPLETE; + die_map_add_die(parent, cache); + return 0; } @@ -259,14 +316,15 @@ static void process_symbol(struct state *state, Dwarf_Die *die, die_callback_t process_func) { debug("%s", state->sym->name); - check(process_func(state, die)); + check(process_func(state, NULL, die)); if (dump_dies) fputs("\n", stderr); } -static int __process_subprogram(struct state *state, Dwarf_Die *die) +static int __process_subprogram(struct state *state, struct die *cache, + Dwarf_Die *die) { - process("subprogram"); + process(cache, "subprogram"); return 0; } @@ -275,10 +333,11 @@ static void process_subprogram(struct state *state, Dwarf_Die *die) process_symbol(state, die, __process_subprogram); } -static int __process_variable(struct state *state, Dwarf_Die *die) +static int __process_variable(struct state *state, struct die *cache, + Dwarf_Die *die) { - process("variable "); - process_type_attr(state, die); + process(cache, "variable "); + process_type_attr(state, cache, die); return 0; } @@ -287,7 +346,8 @@ static void process_variable(struct state *state, Dwarf_Die *die) process_symbol(state, die, __process_variable); } -static int process_exported_symbols(struct state *unused, Dwarf_Die *die) +static int process_exported_symbols(struct state *unused, struct die *cache, + Dwarf_Die *die) { int tag = dwarf_tag(die); @@ -297,7 +357,7 @@ static int process_exported_symbols(struct state *unused, Dwarf_Die *die) case DW_TAG_class_type: case DW_TAG_structure_type: return check(process_die_container( - NULL, die, process_exported_symbols, match_all)); + NULL, cache, die, process_exported_symbols, match_all)); /* Possible exported symbols */ case DW_TAG_subprogram: @@ -321,6 +381,6 @@ static int process_exported_symbols(struct state *unused, Dwarf_Die *die) void process_cu(Dwarf_Die *cudie) { - check(process_die_container(NULL, cudie, process_exported_symbols, + check(process_die_container(NULL, NULL, cudie, process_exported_symbols, match_all)); } diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c index 1763234b6329..7552fde495ef 100644 --- a/scripts/gendwarfksyms/gendwarfksyms.c +++ b/scripts/gendwarfksyms/gendwarfksyms.c @@ -43,6 +43,10 @@ static int process_module(Dwfl_Module *mod, void **userdata, const char *name, debug("%s", name); dbg = dwfl_module_getdwarf(mod, &dwbias); + /* + * Look for exported symbols in each CU, follow the DIE tree, and add + * the entries to die_map. + */ do { res = dwarf_get_units(dbg, cu, &cu, NULL, NULL, &cudie, NULL); if (res < 0) @@ -53,6 +57,8 @@ static int process_module(Dwfl_Module *mod, void **userdata, const char *name, process_cu(&cudie); } while (cu); + die_map_free(); + return DWARF_CB_OK; } diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h index cb9fd78a58da..601f877bc8ca 100644 --- a/scripts/gendwarfksyms/gendwarfksyms.h +++ b/scripts/gendwarfksyms/gendwarfksyms.h @@ -87,6 +87,61 @@ void symbol_read_symtab(int fd); struct symbol *symbol_get(const char *name); void symbol_free(void); +/* + * die.c + */ + +enum die_state { + DIE_INCOMPLETE, + DIE_COMPLETE, + DIE_LAST = DIE_COMPLETE +}; + +enum die_fragment_type { + FRAGMENT_EMPTY, + FRAGMENT_STRING, + FRAGMENT_DIE +}; + +struct die_fragment { + enum die_fragment_type type; + union { + char *str; + uintptr_t addr; + } data; + struct list_head list; +}; + +#define CASE_CONST_TO_STR(name) \ + case name: \ + return #name; + +static inline const char *die_state_name(enum die_state state) +{ + switch (state) { + CASE_CONST_TO_STR(DIE_INCOMPLETE) + CASE_CONST_TO_STR(DIE_COMPLETE) + } + + error("unexpected die_state: %d", state); +} + +struct die { + enum die_state state; + char *fqn; + int tag; + uintptr_t addr; + struct list_head fragments; + struct hlist_node hash; +}; + +int __die_map_get(uintptr_t addr, enum die_state state, struct die **res); +struct die *die_map_get(Dwarf_Die *die, enum die_state state); +void die_map_add_string(struct die *pd, const char *str); +void die_map_add_linebreak(struct die *pd, int linebreak); +void die_map_add_die(struct die *pd, struct die *child); +void die_map_free(void); + /* * dwarf.c */ @@ -96,12 +151,14 @@ struct state { Dwarf_Die die; }; -typedef int (*die_callback_t)(struct state *state, Dwarf_Die *die); +typedef int (*die_callback_t)(struct state *state, struct die *cache, + Dwarf_Die *die); typedef bool (*die_match_callback_t)(Dwarf_Die *die); bool match_all(Dwarf_Die *die); -int process_die_container(struct state *state, Dwarf_Die *die, - die_callback_t func, die_match_callback_t match); +int process_die_container(struct state *state, struct die *cache, + Dwarf_Die *die, die_callback_t func, + die_match_callback_t match); void process_cu(Dwarf_Die *cudie);

[v7,04/18] gendwarfksyms: Add a cache for processed DIEs

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Patch