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Code Issues Releases Wiki Activity

objtool: Fix reloc_hash size 

With CONFIG_DEBUG_INFO, DWARF creates a lot of relocations and
reloc_hash is woefully undersized, which can affect performance
significantly.  Fix that.

Link: https://lore.kernel.org/r/38ef60dc8043270bf3b9dfd139ae2a30ca3f75cc.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
This commit is contained in:
Josh Poimboeuf 2023-05-30 10:20:57 -07:00
parent 53257a977a
commit eb0481bbc4
2 changed files with 14 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
tools/objtool/elf.c
View File

@ -328,12 +328,12 @@ static int read_sections(struct elf *elf)
} }
} }
if (sec->sh.sh_flags & SHF_EXECINSTR)
elf->text_size += sec->sh.sh_size;
list_add_tail(&sec->list, &elf->sections); list_add_tail(&sec->list, &elf->sections);
elf_hash_add(section, &sec->hash, sec->idx); elf_hash_add(section, &sec->hash, sec->idx);
elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name)); elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
if (is_reloc_sec(sec))
elf->num_relocs += sec->sh.sh_size / sec->sh.sh_entsize;
} }
if (opts.stats) { if (opts.stats) {
@ -888,19 +888,18 @@ static int read_reloc(struct section *rsec, int i, struct reloc *reloc)
static int read_relocs(struct elf *elf) static int read_relocs(struct elf *elf)
{ {
unsigned long nr_reloc, max_reloc = 0, tot_reloc = 0; unsigned long nr_reloc, max_reloc = 0;
struct section *rsec; struct section *rsec;
struct reloc *reloc; struct reloc *reloc;
unsigned int symndx; unsigned int symndx;
struct symbol *sym; struct symbol *sym;
int i; int i;
if (!elf_alloc_hash(reloc, elf->text_size / 16)) if (!elf_alloc_hash(reloc, elf->num_relocs))
return -1; return -1;
list_for_each_entry(rsec, &elf->sections, list) { list_for_each_entry(rsec, &elf->sections, list) {
if ((rsec->sh.sh_type != SHT_RELA) && if (!is_reloc_sec(rsec))
(rsec->sh.sh_type != SHT_REL))
continue; continue;
rsec->base = find_section_by_index(elf, rsec->sh.sh_info); rsec->base = find_section_by_index(elf, rsec->sh.sh_info);
@ -942,12 +941,11 @@ static int read_relocs(struct elf *elf)
nr_reloc++; nr_reloc++;
} }
max_reloc = max(max_reloc, nr_reloc); max_reloc = max(max_reloc, nr_reloc);
tot_reloc += nr_reloc;
} }
if (opts.stats) { if (opts.stats) {
printf("max_reloc: %lu\n", max_reloc); printf("max_reloc: %lu\n", max_reloc);
printf("tot_reloc: %lu\n", tot_reloc); printf("num_relocs: %lu\n", elf->num_relocs);
printf("reloc_bits: %d\n", elf->reloc_bits); printf("reloc_bits: %d\n", elf->reloc_bits);
} }

8
tools/objtool/include/objtool/elf.h
View File

@ -90,8 +90,9 @@ struct elf {
int fd; int fd;
bool changed; bool changed;
char *name; char *name;
unsigned int text_size, num_files; unsigned int num_files;
struct list_head sections; struct list_head sections;
unsigned long num_relocs;
int symbol_bits; int symbol_bits;
int symbol_name_bits; int symbol_name_bits;
@ -158,6 +159,11 @@ static inline size_t elf_rela_size(struct elf *elf)
return elf_addr_size(elf) == 4 ? sizeof(Elf32_Rela) : sizeof(Elf64_Rela); return elf_addr_size(elf) == 4 ? sizeof(Elf32_Rela) : sizeof(Elf64_Rela);
} }
static inline bool is_reloc_sec(struct section *sec)
{
return sec->sh.sh_type == SHT_RELA || sec->sh.sh_type == SHT_REL;
}
#define for_each_sec(file, sec) \ #define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list) list_for_each_entry(sec, &file->elf->sections, list)