Commit eb0481bb authored by Josh Poimboeuf's avatar Josh Poimboeuf
Browse files

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: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent 53257a97

tools/objtool/elf.c

+7 −9
Original line number Diff line number Diff line
@@ -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);

		elf_hash_add(section, &sec->hash, sec->idx);

		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) {
@@ -888,19 +888,18 @@ static int read_reloc(struct section *rsec, int i, struct reloc *reloc) 


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 reloc *reloc;

	unsigned int symndx;

	struct symbol *sym;

	int i;



	if (!elf_alloc_hash(reloc, elf->text_size / 16))

	if (!elf_alloc_hash(reloc, elf->num_relocs))

		return -1;



	list_for_each_entry(rsec, &elf->sections, list) {

		if ((rsec->sh.sh_type != SHT_RELA) &&

		    (rsec->sh.sh_type != SHT_REL))

		if (!is_reloc_sec(rsec))

			continue;



		rsec->base = find_section_by_index(elf, rsec->sh.sh_info);
@@ -942,12 +941,11 @@ static int read_relocs(struct elf *elf) 
			nr_reloc++;

		}

		max_reloc = max(max_reloc, nr_reloc);

		tot_reloc += nr_reloc;

	}



	if (opts.stats) {

		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);

	}

tools/objtool/include/objtool/elf.h

+7 −1
Original line number Diff line number Diff line
@@ -90,8 +90,9 @@ struct elf { 
	int fd;

	bool changed;

	char *name;

	unsigned int text_size, num_files;

	unsigned int num_files;

	struct list_head sections;

	unsigned long num_relocs;



	int symbol_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);

}



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)						\

	list_for_each_entry(sec, &file->elf->sections, list)