On Fri, Aug 16, 2024 at 2:39 AM Sami Tolvanen <samitolva...@google.com> wrote:
>
> The compiler may choose not to emit type information in DWARF for all
> aliases, but it's possible for each alias to be exported separately.
> To ensure we find type information for the aliases as well, read
> {section, address} tuples from the symbol table and match symbols also
> by address.
>
> Signed-off-by: Sami Tolvanen <samitolva...@google.com>
> ---
> scripts/gendwarfksyms/gendwarfksyms.c | 2 +
> scripts/gendwarfksyms/gendwarfksyms.h | 7 ++
> scripts/gendwarfksyms/symbols.c | 161 +++++++++++++++++++++++++-
> 3 files changed, 165 insertions(+), 5 deletions(-)
>
> diff --git a/scripts/gendwarfksyms/gendwarfksyms.c
> b/scripts/gendwarfksyms/gendwarfksyms.c
> index d209b237766b..e2f8ee5a4bf3 100644
> --- a/scripts/gendwarfksyms/gendwarfksyms.c
> +++ b/scripts/gendwarfksyms/gendwarfksyms.c
> @@ -118,6 +118,8 @@ int main(int argc, const char **argv)
> return -1;
> }
>
> + check(symbol_read_symtab(fd));
> +
> dwfl = dwfl_begin(&callbacks);
> if (!dwfl) {
> error("dwfl_begin failed for '%s': %s",
> object_files[n],
> diff --git a/scripts/gendwarfksyms/gendwarfksyms.h
> b/scripts/gendwarfksyms/gendwarfksyms.h
> index 03f3e408a839..cb9106dfddb9 100644
> --- a/scripts/gendwarfksyms/gendwarfksyms.h
> +++ b/scripts/gendwarfksyms/gendwarfksyms.h
> @@ -61,6 +61,10 @@ extern bool debug;
> /*
> * symbols.c
> */
> +struct symbol_addr {
> + uint32_t section;
> + Elf64_Addr address;
> +};
>
> static inline u32 name_hash(const char *name)
> {
> @@ -69,10 +73,13 @@ static inline u32 name_hash(const char *name)
>
> struct symbol {
> const char *name;
> + struct symbol_addr addr;
> + struct hlist_node addr_hash;
> struct hlist_node name_hash;
> };
>
> extern int symbol_read_exports(FILE *file);
> +extern int symbol_read_symtab(int fd);
> extern struct symbol *symbol_get(const char *name);
>
> /*
> diff --git a/scripts/gendwarfksyms/symbols.c b/scripts/gendwarfksyms/symbols.c
> index 673ad9cf9e77..f96acb941196 100644
> --- a/scripts/gendwarfksyms/symbols.c
> +++ b/scripts/gendwarfksyms/symbols.c
> @@ -6,11 +6,43 @@
> #include "gendwarfksyms.h"
>
> #define SYMBOL_HASH_BITS 15
> +
> +/* struct symbol_addr -> struct symbol */
> +static DEFINE_HASHTABLE(symbol_addrs, SYMBOL_HASH_BITS);
> +/* name -> struct symbol */
> static DEFINE_HASHTABLE(symbol_names, SYMBOL_HASH_BITS);
>
> +static inline u32 symbol_addr_hash(const struct symbol_addr *addr)
> +{
> + return jhash(addr, sizeof(struct symbol_addr), 0);
> +}
> +
> typedef int (*symbol_callback_t)(struct symbol *, void *arg);
>
> -static int for_each(const char *name, symbol_callback_t func, void *data)
> +static int __for_each_addr(struct symbol *sym, symbol_callback_t func,
> + void *data)
> +{
> + struct hlist_node *tmp;
> + struct symbol *match = NULL;
> + int processed = 0;
> +
> + hash_for_each_possible_safe(symbol_addrs, match, tmp, addr_hash,
> + symbol_addr_hash(&sym->addr)) {
> + if (match == sym)
> + continue; /* Already processed */
> +
> + if (match->addr.section == sym->addr.section &&
> + match->addr.address == sym->addr.address) {
> + check(func(match, data));
> + ++processed;
> + }
> + }
> +
> + return processed;
> +}
> +
> +static int for_each(const char *name, bool name_only, symbol_callback_t func,
> + void *data)
> {
> struct hlist_node *tmp;
> struct symbol *match;
> @@ -23,9 +55,13 @@ static int for_each(const char *name, symbol_callback_t
> func, void *data)
> if (strcmp(match->name, name))
> continue;
>
> + /* Call func for the match, and all address matches */
> if (func)
> check(func(match, data));
>
> + if (!name_only && match->addr.section != SHN_UNDEF)
> + return checkp(__for_each_addr(match, func, data)) + 1;
> +
> return 1;
> }
>
> @@ -34,7 +70,7 @@ static int for_each(const char *name, symbol_callback_t
> func, void *data)
>
> static bool is_exported(const char *name)
> {
> - return checkp(for_each(name, NULL, NULL)) > 0;
> + return checkp(for_each(name, true, NULL, NULL)) > 0;
> }
>
> int symbol_read_exports(FILE *file)
> @@ -57,13 +93,14 @@ int symbol_read_exports(FILE *file)
> if (is_exported(name))
> continue; /* Ignore duplicates */
>
> - sym = malloc(sizeof(struct symbol));
> + sym = calloc(1, sizeof(struct symbol));
I am tired of noise changes when reviewing this patch set.
2/19 added malloc(), which is immediately replaced with calloc() by 3/19.
--
Best Regards
Masahiro Yamada
