| Message ID | 20241008183823.36676-33-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Implement DWARF modversions | expand |
On 10/8/24 20:38, Sami Tolvanen wrote: > Add support for producing genksyms-style symtypes files. Process > die_map to find the longest expansions for each type, and use symtypes > references in type definitions. The basic file format is similar to > genksyms, with two notable exceptions: > > 1. Type names with spaces (common with Rust) in references are > wrapped in single quotes. E.g.: > > s#'core::result::Result<u8, core::num::error::ParseIntError>' > > 2. The actual type definition is the simple parsed DWARF format we > output with --dump-dies, not the preprocessed C-style format > genksyms produces. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > Acked-by: Neal Gompa <neal@gompa.dev> > --- > scripts/gendwarfksyms/Makefile | 1 + > scripts/gendwarfksyms/die.c | 11 + > scripts/gendwarfksyms/dwarf.c | 1 + > scripts/gendwarfksyms/gendwarfksyms.c | 36 ++- > scripts/gendwarfksyms/gendwarfksyms.h | 19 ++ > scripts/gendwarfksyms/symbols.c | 4 +- > scripts/gendwarfksyms/types.c | 359 ++++++++++++++++++++++++++ > 7 files changed, 428 insertions(+), 3 deletions(-) > create mode 100644 scripts/gendwarfksyms/types.c > > diff --git a/scripts/gendwarfksyms/Makefile b/scripts/gendwarfksyms/Makefile > index c06145d84df8..6540282dc746 100644 > --- a/scripts/gendwarfksyms/Makefile > +++ b/scripts/gendwarfksyms/Makefile > @@ -6,5 +6,6 @@ gendwarfksyms-objs += cache.o > gendwarfksyms-objs += die.o > gendwarfksyms-objs += dwarf.o > gendwarfksyms-objs += symbols.o > +gendwarfksyms-objs += types.o > > HOSTLDLIBS_gendwarfksyms := -ldw -lelf > diff --git a/scripts/gendwarfksyms/die.c b/scripts/gendwarfksyms/die.c > index 2829387fd815..df1ca3a032bb 100644 > --- a/scripts/gendwarfksyms/die.c > +++ b/scripts/gendwarfksyms/die.c > @@ -22,6 +22,7 @@ static inline unsigned int die_hash(uintptr_t addr, enum die_state state) > static void init_die(struct die *cd) > { > cd->state = DIE_INCOMPLETE; > + cd->mapped = false; > cd->fqn = NULL; > cd->tag = -1; > cd->addr = 0; > @@ -83,6 +84,16 @@ static void reset_die(struct die *cd) > init_die(cd); > } > > +void die_map_for_each(die_map_callback_t func, void *arg) > +{ > + struct hlist_node *tmp; > + struct die *cd; > + > + hash_for_each_safe(die_map, cd, tmp, hash) { > + func(cd, arg); > + } > +} > + > void die_map_free(void) > { > struct hlist_node *tmp; > diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c > index d67cac16f8fb..e1a9e9061b1d 100644 > --- a/scripts/gendwarfksyms/dwarf.c > +++ b/scripts/gendwarfksyms/dwarf.c > @@ -728,6 +728,7 @@ static void process_symbol(struct state *state, Dwarf_Die *die, > { > debug("%s", state->sym->name); > check(process_func(state, NULL, die)); > + state->sym->state = SYMBOL_MAPPED; > if (dump_dies) > fputs("\n", stderr); > } > diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c > index d40692a703bb..24c87523fc3a 100644 > --- a/scripts/gendwarfksyms/gendwarfksyms.c > +++ b/scripts/gendwarfksyms/gendwarfksyms.c > @@ -21,6 +21,11 @@ int debug; > int dump_dies; > /* Print debugging information about die_map changes */ > int dump_die_map; > +/* Print out type strings (i.e. type_map) */ > +int dump_types; > +/* Write a symtypes file */ > +int symtypes; > +static const char *symtypes_file; > > static void usage(void) > { > @@ -29,6 +34,8 @@ static void usage(void) > " -d, --debug Print debugging information\n" > " --dump-dies Dump DWARF DIE contents\n" > " --dump-die-map Print debugging information about die_map changes\n" > + " --dump-types Dump type strings\n" > + " -T, --symtypes file Write a symtypes file\n" > " -h, --help Print this message\n" > "\n", > stderr); > @@ -41,6 +48,7 @@ static int process_module(Dwfl_Module *mod, void **userdata, const char *name, > Dwarf_Die cudie; > Dwarf_CU *cu = NULL; > Dwarf *dbg; > + FILE *symfile = arg; > int res; > > debug("%s", name); > @@ -60,6 +68,10 @@ static int process_module(Dwfl_Module *mod, void **userdata, const char *name, > process_cu(&cudie); > } while (cu); > > + /* > + * Use die_map to expand type strings and write them to `symfile`. > + */ > + generate_symtypes(symfile); > die_map_free(); > > return DWARF_CB_OK; > @@ -72,22 +84,29 @@ static const Dwfl_Callbacks callbacks = { > > int main(int argc, char **argv) > { > + FILE *symfile = NULL; > unsigned int n; > int opt; > > struct option opts[] = { { "debug", 0, NULL, 'd' }, > { "dump-dies", 0, &dump_dies, 1 }, > { "dump-die-map", 0, &dump_die_map, 1 }, > + { "dump-types", 0, &dump_types, 1 }, > + { "symtypes", 1, NULL, 'T' }, > { "help", 0, NULL, 'h' }, > { 0, 0, NULL, 0 } }; > > - while ((opt = getopt_long(argc, argv, "dh", opts, NULL)) != EOF) { > + while ((opt = getopt_long(argc, argv, "dT:h", opts, NULL)) != EOF) { > switch (opt) { > case 0: > break; > case 'd': > debug = 1; > break; > + case 'T': > + symtypes = 1; > + symtypes_file = optarg; > + break; > case 'h': > usage(); > return 0; > @@ -107,6 +126,16 @@ int main(int argc, char **argv) > > symbol_read_exports(stdin); > > + if (symtypes_file) { > + symfile = fopen(symtypes_file, "w"); > + > + if (!symfile) { > + error("fopen failed for '%s': %s", symtypes_file, > + strerror(errno)); > + return -1; Nit: The 'return -1;' statement is not needed since error() doesn't return. > + } > + } > + > for (n = optind; n < argc; n++) { > Dwfl *dwfl; > int fd; > @@ -129,11 +158,14 @@ int main(int argc, char **argv) > > dwfl_report_end(dwfl, NULL, NULL); > > - if (dwfl_getmodules(dwfl, &process_module, NULL, 0)) > + if (dwfl_getmodules(dwfl, &process_module, symfile, 0)) > error("dwfl_getmodules failed for '%s'", argv[n]); > > dwfl_end(dwfl); > } > > + if (symfile) > + check(fclose(symfile)); > + > return 0; > } > diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h > index 126916e85ee0..e47b5e967520 100644 > --- a/scripts/gendwarfksyms/gendwarfksyms.h > +++ b/scripts/gendwarfksyms/gendwarfksyms.h > @@ -25,6 +25,8 @@ > extern int debug; > extern int dump_dies; > extern int dump_die_map; > +extern int dump_types; > +extern int symtypes; > > /* > * Output helpers > @@ -93,6 +95,11 @@ static inline unsigned int addr_hash(uintptr_t addr) > return hash_ptr((const void *)addr); > } > > +enum symbol_state { > + SYMBOL_UNPROCESSED, > + SYMBOL_MAPPED, > +}; > + > struct symbol_addr { > uint32_t section; > Elf64_Addr address; > @@ -103,6 +110,8 @@ struct symbol { > struct symbol_addr addr; > struct hlist_node addr_hash; > struct hlist_node name_hash; > + enum symbol_state state; > + uintptr_t die_addr; > }; > > typedef void (*symbol_callback_t)(struct symbol *, void *arg); > @@ -156,6 +165,7 @@ static inline const char *die_state_name(enum die_state state) > > struct die { > enum die_state state; > + bool mapped; > char *fqn; > int tag; > uintptr_t addr; > @@ -163,10 +173,13 @@ struct die { > struct hlist_node hash; > }; > > +typedef void (*die_map_callback_t)(struct die *, void *arg); > + > 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_for_each(die_map_callback_t func, void *arg); > void die_map_add_die(struct die *pd, struct die *child); > void die_map_free(void); > > @@ -228,4 +241,10 @@ int process_die_container(struct state *state, struct die *cache, > > void process_cu(Dwarf_Die *cudie); > > +/* > + * types.c > + */ > + > +void generate_symtypes(FILE *file); > + > #endif /* __GENDWARFKSYMS_H */ > diff --git a/scripts/gendwarfksyms/symbols.c b/scripts/gendwarfksyms/symbols.c > index 6cb99b8769ea..e414257333e5 100644 > --- a/scripts/gendwarfksyms/symbols.c > +++ b/scripts/gendwarfksyms/symbols.c > @@ -92,6 +92,7 @@ void symbol_read_exports(FILE *file) > sym = xcalloc(1, sizeof(struct symbol)); > sym->name = name; > sym->addr.section = SHN_UNDEF; > + sym->state = SYMBOL_UNPROCESSED; > > hash_add(symbol_names, &sym->name_hash, hash_str(sym->name)); > ++nsym; > @@ -107,7 +108,8 @@ static void get_symbol(struct symbol *sym, void *arg) > { > struct symbol **res = arg; > > - *res = sym; > + if (sym->state == SYMBOL_UNPROCESSED) > + *res = sym; > } What is the reason to check that the symbol is in the unprocessed state here? > > struct symbol *symbol_get(const char *name) > diff --git a/scripts/gendwarfksyms/types.c b/scripts/gendwarfksyms/types.c > new file mode 100644 > index 000000000000..c05811299eba > --- /dev/null > +++ b/scripts/gendwarfksyms/types.c > @@ -0,0 +1,359 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2024 Google LLC > + */ > + > +#include "gendwarfksyms.h" > + > +static struct expansion_cache expansion_cache; > + > +/* > + * A simple linked list of shared or owned strings to avoid copying strings > + * around when not necessary. > + */ > +struct type_list_entry { > + const char *str; > + void *owned; > + struct list_head list; > +}; > + > +static void type_list_free(struct list_head *list) > +{ > + struct type_list_entry *entry; > + struct type_list_entry *tmp; > + > + list_for_each_entry_safe(entry, tmp, list, list) { > + if (entry->owned) > + free(entry->owned); > + free(entry); > + } > + > + INIT_LIST_HEAD(list); > +} > + > +static int type_list_append(struct list_head *list, const char *s, void *owned) > +{ > + struct type_list_entry *entry; > + > + if (!s) > + return 0; > + > + entry = xmalloc(sizeof(struct type_list_entry)); > + entry->str = s; > + entry->owned = owned; > + list_add_tail(&entry->list, list); > + > + return strlen(entry->str); > +} > + > +static void type_list_write(struct list_head *list, FILE *file) > +{ > + struct type_list_entry *entry; > + > + list_for_each_entry(entry, list, list) { > + if (entry->str) > + checkp(fputs(entry->str, file)); > + } > +} > + > +/* > + * An expanded type string in symtypes format. > + */ > +struct type_expansion { > + char *name; > + size_t len; > + struct list_head expanded; > + struct hlist_node hash; > +}; > + > +static void type_expansion_init(struct type_expansion *type) > +{ > + type->name = NULL; > + type->len = 0; > + INIT_LIST_HEAD(&type->expanded); > +} > + > +static inline void type_expansion_free(struct type_expansion *type) > +{ > + free(type->name); > + type->name = NULL; > + type->len = 0; > + type_list_free(&type->expanded); > +} > + > +static void type_expansion_append(struct type_expansion *type, const char *s, > + void *owned) > +{ > + type->len += type_list_append(&type->expanded, s, owned); > +} > + > +/* > + * type_map -- the longest expansions for each type. > + * > + * const char *name -> struct type_expansion * > + */ > +#define TYPE_HASH_BITS 16 > +static HASHTABLE_DEFINE(type_map, 1 << TYPE_HASH_BITS); > + > +static int type_map_get(const char *name, struct type_expansion **res) > +{ > + struct type_expansion *e; > + > + hash_for_each_possible(type_map, e, hash, hash_str(name)) { > + if (!strcmp(name, e->name)) { > + *res = e; > + return 0; > + } > + } > + > + return -1; > +} > + > +static void type_map_add(const char *name, struct type_expansion *type) > +{ > + struct type_expansion *e; > + > + if (type_map_get(name, &e)) { > + e = xmalloc(sizeof(struct type_expansion)); > + type_expansion_init(e); > + e->name = xstrdup(name); > + > + hash_add(type_map, &e->hash, hash_str(e->name)); > + > + if (dump_types) > + debug("adding %s", e->name); > + } else { > + /* Use the longest available expansion */ > + if (type->len <= e->len) > + return; > + > + type_list_free(&e->expanded); > + > + if (dump_types) > + debug("replacing %s", e->name); > + } > + > + /* Take ownership of type->expanded */ > + list_replace_init(&type->expanded, &e->expanded); > + e->len = type->len; > + > + if (dump_types) { > + checkp(fputs(e->name, stderr)); > + checkp(fputs(" ", stderr)); > + type_list_write(&e->expanded, stderr); > + checkp(fputs("\n", stderr)); > + } > +} > + > +static void type_map_write(FILE *file) > +{ > + struct type_expansion *e; > + struct hlist_node *tmp; > + > + if (!file) > + return; > + > + hash_for_each_safe(type_map, e, tmp, hash) { > + checkp(fputs(e->name, file)); > + checkp(fputs(" ", file)); > + type_list_write(&e->expanded, file); > + checkp(fputs("\n", file)); > + } > +} > + > +static void type_map_free(void) > +{ > + struct type_expansion *e; > + struct hlist_node *tmp; > + > + hash_for_each_safe(type_map, e, tmp, hash) { > + type_expansion_free(e); > + free(e); > + } > + > + hash_init(type_map); > +} > + > +/* > + * Type reference format: <prefix>#<name>, where prefix: > + * s -> structure > + * u -> union > + * e -> enum > + * t -> typedef > + * > + * Names with spaces are additionally wrapped in single quotes. > + */ > +static char get_type_prefix(int tag) > +{ > + switch (tag) { > + case DW_TAG_class_type: > + case DW_TAG_structure_type: > + return 's'; > + case DW_TAG_union_type: > + return 'u'; > + case DW_TAG_enumeration_type: > + return 'e'; > + case DW_TAG_typedef_type: > + return 't'; > + default: > + return 0; > + } > +} > + > +static char *get_type_name(struct die *cache) > +{ > + const char *quote; > + char prefix; > + char *name; > + > + if (cache->state == DIE_INCOMPLETE) { > + warn("found incomplete cache entry: %p", cache); > + return NULL; > + } > + if (!cache->fqn || !*cache->fqn) > + return NULL; > + > + prefix = get_type_prefix(cache->tag); > + if (!prefix) > + return NULL; > + > + /* Wrap names with spaces in single quotes */ > + quote = strstr(cache->fqn, " ") ? "'" : ""; > + > + /* <prefix>#<type_name>\0 */ > + if (asprintf(&name, "%c#%s%s%s", prefix, quote, cache->fqn, quote) < 0) > + error("asprintf failed for '%s'", cache->fqn); > + > + return name; > +} > + > +static void __type_expand(struct die *cache, struct type_expansion *type, > + bool recursive); > + > +static void type_expand_child(struct die *cache, struct type_expansion *type, > + bool recursive) > +{ > + struct type_expansion child; > + char *name; > + > + name = get_type_name(cache); > + if (!name) { > + __type_expand(cache, type, recursive); > + return; > + } > + > + if (recursive && !__cache_was_expanded(&expansion_cache, cache->addr)) { > + __cache_mark_expanded(&expansion_cache, cache->addr); > + type_expansion_init(&child); > + __type_expand(cache, &child, true); > + type_map_add(name, &child); > + type_expansion_free(&child); > + } > + > + type_expansion_append(type, name, name); > +} > + > +static void __type_expand(struct die *cache, struct type_expansion *type, > + bool recursive) > +{ > + struct die_fragment *df; > + struct die *child; > + > + list_for_each_entry(df, &cache->fragments, list) { > + switch (df->type) { > + case FRAGMENT_STRING: > + type_expansion_append(type, df->data.str, NULL); > + break; > + case FRAGMENT_DIE: > + /* Use a complete die_map expansion if available */ > + if (__die_map_get(df->data.addr, DIE_COMPLETE, > + &child) && > + __die_map_get(df->data.addr, DIE_UNEXPANDED, > + &child)) > + error("unknown child: %" PRIxPTR, > + df->data.addr); > + > + type_expand_child(child, type, recursive); > + break; > + case FRAGMENT_LINEBREAK: > + /* > + * Keep whitespace in the symtypes format, but avoid > + * repeated spaces. > + */ > + if (list_is_last(&df->list, &cache->fragments) || > + list_next_entry(df, list)->type != > + FRAGMENT_LINEBREAK) > + type_expansion_append(type, " ", NULL); > + break; > + default: > + error("empty die_fragment in %p", cache); > + } > + } > +} > + > +static void type_expand(struct die *cache, struct type_expansion *type, > + bool recursive) > +{ > + type_expansion_init(type); > + __type_expand(cache, type, recursive); > + cache_clear_expanded(&expansion_cache); > +} > + > +static void expand_type(struct die *cache, void *arg) > +{ > + struct type_expansion type; > + char *name; > + > + if (cache->mapped) > + return; > + > + cache->mapped = true; > + > + /* > + * Skip unexpanded die_map entries if there's a complete > + * expansion available for this DIE. > + */ > + if (cache->state == DIE_UNEXPANDED && > + !__die_map_get(cache->addr, DIE_COMPLETE, &cache)) { > + if (cache->mapped) > + return; > + > + cache->mapped = true; > + } > + > + name = get_type_name(cache); > + if (!name) > + return; > + > + debug("%s", name); > + type_expand(cache, &type, true); > + type_map_add(name, &type); > + > + type_expansion_free(&type); > + free(name); > +} > + > +void generate_symtypes(FILE *file) > +{ > + hash_init(expansion_cache.cache); > + > + /* > + * die_map processing: > + * > + * 1. die_map contains all types referenced in exported symbol > + * signatures, but can contain duplicates just like the original > + * DWARF, and some references may not be fully expanded depending > + * on how far we processed the DIE tree for that specific symbol. > + * > + * For each die_map entry, find the longest available expansion, > + * and add it to type_map. > + */ > + die_map_for_each(expand_type, NULL); > + > + /* > + * 2. If a symtypes file is requested, write type_map contents to > + * the file. > + */ > + type_map_write(file); > + type_map_free(); > +}
Hi Petr, On Thu, Oct 17, 2024 at 7:13 AM Petr Pavlu <petr.pavlu@suse.com> wrote: > > On 10/8/24 20:38, Sami Tolvanen wrote: > > + if (symtypes_file) { > > + symfile = fopen(symtypes_file, "w"); > > + > > + if (!symfile) { > > + error("fopen failed for '%s': %s", symtypes_file, > > + strerror(errno)); > > + return -1; > > Nit: The 'return -1;' statement is not needed since error() doesn't > return. Ah, missed this one. I'll fix this in v5. > > @@ -107,7 +108,8 @@ static void get_symbol(struct symbol *sym, void *arg) > > { > > struct symbol **res = arg; > > > > - *res = sym; > > + if (sym->state == SYMBOL_UNPROCESSED) > > + *res = sym; > > } > > What is the reason to check that the symbol is in the unprocessed state > here? At this point it's mostly a sanity check to avoid extra work in case we run into more than one DIE that matches a symbol (or its aliases). This actually happened in earlier versions because we handled symbol type pointers (patch 17) as soon as we found them, but now that we just save them for later in case they're needed, this probably isn't strictly necessary anymore. I don't see any downsides in keeping this check though. Sami
diff --git a/scripts/gendwarfksyms/Makefile b/scripts/gendwarfksyms/Makefile index c06145d84df8..6540282dc746 100644 --- a/scripts/gendwarfksyms/Makefile +++ b/scripts/gendwarfksyms/Makefile @@ -6,5 +6,6 @@ gendwarfksyms-objs += cache.o gendwarfksyms-objs += die.o gendwarfksyms-objs += dwarf.o gendwarfksyms-objs += symbols.o +gendwarfksyms-objs += types.o HOSTLDLIBS_gendwarfksyms := -ldw -lelf diff --git a/scripts/gendwarfksyms/die.c b/scripts/gendwarfksyms/die.c index 2829387fd815..df1ca3a032bb 100644 --- a/scripts/gendwarfksyms/die.c +++ b/scripts/gendwarfksyms/die.c @@ -22,6 +22,7 @@ static inline unsigned int die_hash(uintptr_t addr, enum die_state state) static void init_die(struct die *cd) { cd->state = DIE_INCOMPLETE; + cd->mapped = false; cd->fqn = NULL; cd->tag = -1; cd->addr = 0; @@ -83,6 +84,16 @@ static void reset_die(struct die *cd) init_die(cd); } +void die_map_for_each(die_map_callback_t func, void *arg) +{ + struct hlist_node *tmp; + struct die *cd; + + hash_for_each_safe(die_map, cd, tmp, hash) { + func(cd, arg); + } +} + void die_map_free(void) { struct hlist_node *tmp; diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c index d67cac16f8fb..e1a9e9061b1d 100644 --- a/scripts/gendwarfksyms/dwarf.c +++ b/scripts/gendwarfksyms/dwarf.c @@ -728,6 +728,7 @@ static void process_symbol(struct state *state, Dwarf_Die *die, { debug("%s", state->sym->name); check(process_func(state, NULL, die)); + state->sym->state = SYMBOL_MAPPED; if (dump_dies) fputs("\n", stderr); } diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c index d40692a703bb..24c87523fc3a 100644 --- a/scripts/gendwarfksyms/gendwarfksyms.c +++ b/scripts/gendwarfksyms/gendwarfksyms.c @@ -21,6 +21,11 @@ int debug; int dump_dies; /* Print debugging information about die_map changes */ int dump_die_map; +/* Print out type strings (i.e. type_map) */ +int dump_types; +/* Write a symtypes file */ +int symtypes; +static const char *symtypes_file; static void usage(void) { @@ -29,6 +34,8 @@ static void usage(void) " -d, --debug Print debugging information\n" " --dump-dies Dump DWARF DIE contents\n" " --dump-die-map Print debugging information about die_map changes\n" + " --dump-types Dump type strings\n" + " -T, --symtypes file Write a symtypes file\n" " -h, --help Print this message\n" "\n", stderr); @@ -41,6 +48,7 @@ static int process_module(Dwfl_Module *mod, void **userdata, const char *name, Dwarf_Die cudie; Dwarf_CU *cu = NULL; Dwarf *dbg; + FILE *symfile = arg; int res; debug("%s", name); @@ -60,6 +68,10 @@ static int process_module(Dwfl_Module *mod, void **userdata, const char *name, process_cu(&cudie); } while (cu); + /* + * Use die_map to expand type strings and write them to `symfile`. + */ + generate_symtypes(symfile); die_map_free(); return DWARF_CB_OK; @@ -72,22 +84,29 @@ static const Dwfl_Callbacks callbacks = { int main(int argc, char **argv) { + FILE *symfile = NULL; unsigned int n; int opt; struct option opts[] = { { "debug", 0, NULL, 'd' }, { "dump-dies", 0, &dump_dies, 1 }, { "dump-die-map", 0, &dump_die_map, 1 }, + { "dump-types", 0, &dump_types, 1 }, + { "symtypes", 1, NULL, 'T' }, { "help", 0, NULL, 'h' }, { 0, 0, NULL, 0 } }; - while ((opt = getopt_long(argc, argv, "dh", opts, NULL)) != EOF) { + while ((opt = getopt_long(argc, argv, "dT:h", opts, NULL)) != EOF) { switch (opt) { case 0: break; case 'd': debug = 1; break; + case 'T': + symtypes = 1; + symtypes_file = optarg; + break; case 'h': usage(); return 0; @@ -107,6 +126,16 @@ int main(int argc, char **argv) symbol_read_exports(stdin); + if (symtypes_file) { + symfile = fopen(symtypes_file, "w"); + + if (!symfile) { + error("fopen failed for '%s': %s", symtypes_file, + strerror(errno)); + return -1; + } + } + for (n = optind; n < argc; n++) { Dwfl *dwfl; int fd; @@ -129,11 +158,14 @@ int main(int argc, char **argv) dwfl_report_end(dwfl, NULL, NULL); - if (dwfl_getmodules(dwfl, &process_module, NULL, 0)) + if (dwfl_getmodules(dwfl, &process_module, symfile, 0)) error("dwfl_getmodules failed for '%s'", argv[n]); dwfl_end(dwfl); } + if (symfile) + check(fclose(symfile)); + return 0; } diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h index 126916e85ee0..e47b5e967520 100644 --- a/scripts/gendwarfksyms/gendwarfksyms.h +++ b/scripts/gendwarfksyms/gendwarfksyms.h @@ -25,6 +25,8 @@ extern int debug; extern int dump_dies; extern int dump_die_map; +extern int dump_types; +extern int symtypes; /* * Output helpers @@ -93,6 +95,11 @@ static inline unsigned int addr_hash(uintptr_t addr) return hash_ptr((const void *)addr); } +enum symbol_state { + SYMBOL_UNPROCESSED, + SYMBOL_MAPPED, +}; + struct symbol_addr { uint32_t section; Elf64_Addr address; @@ -103,6 +110,8 @@ struct symbol { struct symbol_addr addr; struct hlist_node addr_hash; struct hlist_node name_hash; + enum symbol_state state; + uintptr_t die_addr; }; typedef void (*symbol_callback_t)(struct symbol *, void *arg); @@ -156,6 +165,7 @@ static inline const char *die_state_name(enum die_state state) struct die { enum die_state state; + bool mapped; char *fqn; int tag; uintptr_t addr; @@ -163,10 +173,13 @@ struct die { struct hlist_node hash; }; +typedef void (*die_map_callback_t)(struct die *, void *arg); + 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_for_each(die_map_callback_t func, void *arg); void die_map_add_die(struct die *pd, struct die *child); void die_map_free(void); @@ -228,4 +241,10 @@ int process_die_container(struct state *state, struct die *cache, void process_cu(Dwarf_Die *cudie); +/* + * types.c + */ + +void generate_symtypes(FILE *file); + #endif /* __GENDWARFKSYMS_H */ diff --git a/scripts/gendwarfksyms/symbols.c b/scripts/gendwarfksyms/symbols.c index 6cb99b8769ea..e414257333e5 100644 --- a/scripts/gendwarfksyms/symbols.c +++ b/scripts/gendwarfksyms/symbols.c @@ -92,6 +92,7 @@ void symbol_read_exports(FILE *file) sym = xcalloc(1, sizeof(struct symbol)); sym->name = name; sym->addr.section = SHN_UNDEF; + sym->state = SYMBOL_UNPROCESSED; hash_add(symbol_names, &sym->name_hash, hash_str(sym->name)); ++nsym; @@ -107,7 +108,8 @@ static void get_symbol(struct symbol *sym, void *arg) { struct symbol **res = arg; - *res = sym; + if (sym->state == SYMBOL_UNPROCESSED) + *res = sym; } struct symbol *symbol_get(const char *name) diff --git a/scripts/gendwarfksyms/types.c b/scripts/gendwarfksyms/types.c new file mode 100644 index 000000000000..c05811299eba --- /dev/null +++ b/scripts/gendwarfksyms/types.c @@ -0,0 +1,359 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2024 Google LLC + */ + +#include "gendwarfksyms.h" + +static struct expansion_cache expansion_cache; + +/* + * A simple linked list of shared or owned strings to avoid copying strings + * around when not necessary. + */ +struct type_list_entry { + const char *str; + void *owned; + struct list_head list; +}; + +static void type_list_free(struct list_head *list) +{ + struct type_list_entry *entry; + struct type_list_entry *tmp; + + list_for_each_entry_safe(entry, tmp, list, list) { + if (entry->owned) + free(entry->owned); + free(entry); + } + + INIT_LIST_HEAD(list); +} + +static int type_list_append(struct list_head *list, const char *s, void *owned) +{ + struct type_list_entry *entry; + + if (!s) + return 0; + + entry = xmalloc(sizeof(struct type_list_entry)); + entry->str = s; + entry->owned = owned; + list_add_tail(&entry->list, list); + + return strlen(entry->str); +} + +static void type_list_write(struct list_head *list, FILE *file) +{ + struct type_list_entry *entry; + + list_for_each_entry(entry, list, list) { + if (entry->str) + checkp(fputs(entry->str, file)); + } +} + +/* + * An expanded type string in symtypes format. + */ +struct type_expansion { + char *name; + size_t len; + struct list_head expanded; + struct hlist_node hash; +}; + +static void type_expansion_init(struct type_expansion *type) +{ + type->name = NULL; + type->len = 0; + INIT_LIST_HEAD(&type->expanded); +} + +static inline void type_expansion_free(struct type_expansion *type) +{ + free(type->name); + type->name = NULL; + type->len = 0; + type_list_free(&type->expanded); +} + +static void type_expansion_append(struct type_expansion *type, const char *s, + void *owned) +{ + type->len += type_list_append(&type->expanded, s, owned); +} + +/* + * type_map -- the longest expansions for each type. + * + * const char *name -> struct type_expansion * + */ +#define TYPE_HASH_BITS 16 +static HASHTABLE_DEFINE(type_map, 1 << TYPE_HASH_BITS); + +static int type_map_get(const char *name, struct type_expansion **res) +{ + struct type_expansion *e; + + hash_for_each_possible(type_map, e, hash, hash_str(name)) { + if (!strcmp(name, e->name)) { + *res = e; + return 0; + } + } + + return -1; +} + +static void type_map_add(const char *name, struct type_expansion *type) +{ + struct type_expansion *e; + + if (type_map_get(name, &e)) { + e = xmalloc(sizeof(struct type_expansion)); + type_expansion_init(e); + e->name = xstrdup(name); + + hash_add(type_map, &e->hash, hash_str(e->name)); + + if (dump_types) + debug("adding %s", e->name); + } else { + /* Use the longest available expansion */ + if (type->len <= e->len) + return; + + type_list_free(&e->expanded); + + if (dump_types) + debug("replacing %s", e->name); + } + + /* Take ownership of type->expanded */ + list_replace_init(&type->expanded, &e->expanded); + e->len = type->len; + + if (dump_types) { + checkp(fputs(e->name, stderr)); + checkp(fputs(" ", stderr)); + type_list_write(&e->expanded, stderr); + checkp(fputs("\n", stderr)); + } +} + +static void type_map_write(FILE *file) +{ + struct type_expansion *e; + struct hlist_node *tmp; + + if (!file) + return; + + hash_for_each_safe(type_map, e, tmp, hash) { + checkp(fputs(e->name, file)); + checkp(fputs(" ", file)); + type_list_write(&e->expanded, file); + checkp(fputs("\n", file)); + } +} + +static void type_map_free(void) +{ + struct type_expansion *e; + struct hlist_node *tmp; + + hash_for_each_safe(type_map, e, tmp, hash) { + type_expansion_free(e); + free(e); + } + + hash_init(type_map); +} + +/* + * Type reference format: <prefix>#<name>, where prefix: + * s -> structure + * u -> union + * e -> enum + * t -> typedef + * + * Names with spaces are additionally wrapped in single quotes. + */ +static char get_type_prefix(int tag) +{ + switch (tag) { + case DW_TAG_class_type: + case DW_TAG_structure_type: + return 's'; + case DW_TAG_union_type: + return 'u'; + case DW_TAG_enumeration_type: + return 'e'; + case DW_TAG_typedef_type: + return 't'; + default: + return 0; + } +} + +static char *get_type_name(struct die *cache) +{ + const char *quote; + char prefix; + char *name; + + if (cache->state == DIE_INCOMPLETE) { + warn("found incomplete cache entry: %p", cache); + return NULL; + } + if (!cache->fqn || !*cache->fqn) + return NULL; + + prefix = get_type_prefix(cache->tag); + if (!prefix) + return NULL; + + /* Wrap names with spaces in single quotes */ + quote = strstr(cache->fqn, " ") ? "'" : ""; + + /* <prefix>#<type_name>\0 */ + if (asprintf(&name, "%c#%s%s%s", prefix, quote, cache->fqn, quote) < 0) + error("asprintf failed for '%s'", cache->fqn); + + return name; +} + +static void __type_expand(struct die *cache, struct type_expansion *type, + bool recursive); + +static void type_expand_child(struct die *cache, struct type_expansion *type, + bool recursive) +{ + struct type_expansion child; + char *name; + + name = get_type_name(cache); + if (!name) { + __type_expand(cache, type, recursive); + return; + } + + if (recursive && !__cache_was_expanded(&expansion_cache, cache->addr)) { + __cache_mark_expanded(&expansion_cache, cache->addr); + type_expansion_init(&child); + __type_expand(cache, &child, true); + type_map_add(name, &child); + type_expansion_free(&child); + } + + type_expansion_append(type, name, name); +} + +static void __type_expand(struct die *cache, struct type_expansion *type, + bool recursive) +{ + struct die_fragment *df; + struct die *child; + + list_for_each_entry(df, &cache->fragments, list) { + switch (df->type) { + case FRAGMENT_STRING: + type_expansion_append(type, df->data.str, NULL); + break; + case FRAGMENT_DIE: + /* Use a complete die_map expansion if available */ + if (__die_map_get(df->data.addr, DIE_COMPLETE, + &child) && + __die_map_get(df->data.addr, DIE_UNEXPANDED, + &child)) + error("unknown child: %" PRIxPTR, + df->data.addr); + + type_expand_child(child, type, recursive); + break; + case FRAGMENT_LINEBREAK: + /* + * Keep whitespace in the symtypes format, but avoid + * repeated spaces. + */ + if (list_is_last(&df->list, &cache->fragments) || + list_next_entry(df, list)->type != + FRAGMENT_LINEBREAK) + type_expansion_append(type, " ", NULL); + break; + default: + error("empty die_fragment in %p", cache); + } + } +} + +static void type_expand(struct die *cache, struct type_expansion *type, + bool recursive) +{ + type_expansion_init(type); + __type_expand(cache, type, recursive); + cache_clear_expanded(&expansion_cache); +} + +static void expand_type(struct die *cache, void *arg) +{ + struct type_expansion type; + char *name; + + if (cache->mapped) + return; + + cache->mapped = true; + + /* + * Skip unexpanded die_map entries if there's a complete + * expansion available for this DIE. + */ + if (cache->state == DIE_UNEXPANDED && + !__die_map_get(cache->addr, DIE_COMPLETE, &cache)) { + if (cache->mapped) + return; + + cache->mapped = true; + } + + name = get_type_name(cache); + if (!name) + return; + + debug("%s", name); + type_expand(cache, &type, true); + type_map_add(name, &type); + + type_expansion_free(&type); + free(name); +} + +void generate_symtypes(FILE *file) +{ + hash_init(expansion_cache.cache); + + /* + * die_map processing: + * + * 1. die_map contains all types referenced in exported symbol + * signatures, but can contain duplicates just like the original + * DWARF, and some references may not be fully expanded depending + * on how far we processed the DIE tree for that specific symbol. + * + * For each die_map entry, find the longest available expansion, + * and add it to type_map. + */ + die_map_for_each(expand_type, NULL); + + /* + * 2. If a symtypes file is requested, write type_map contents to + * the file. + */ + type_map_write(file); + type_map_free(); +}
Add support for producing genksyms-style symtypes files. Process die_map to find the longest expansions for each type, and use symtypes references in type definitions. The basic file format is similar to genksyms, with two notable exceptions: 1. Type names with spaces (common with Rust) in references are wrapped in single quotes. E.g.: s#'core::result::Result<u8, core::num::error::ParseIntError>' 2. The actual type definition is the simple parsed DWARF format we output with --dump-dies, not the preprocessed C-style format genksyms produces. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Neal Gompa <neal@gompa.dev> --- scripts/gendwarfksyms/Makefile | 1 + scripts/gendwarfksyms/die.c | 11 + scripts/gendwarfksyms/dwarf.c | 1 + scripts/gendwarfksyms/gendwarfksyms.c | 36 ++- scripts/gendwarfksyms/gendwarfksyms.h | 19 ++ scripts/gendwarfksyms/symbols.c | 4 +- scripts/gendwarfksyms/types.c | 359 ++++++++++++++++++++++++++ 7 files changed, 428 insertions(+), 3 deletions(-) create mode 100644 scripts/gendwarfksyms/types.c