Commit ebcef730 authored by Josh Poimboeuf's avatar Josh Poimboeuf
Browse files

objtool: Get rid of reloc->list 

Now that all relocs are allocated in an array, the linked list is no
longer needed.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 49.02G
- After:  peak heap memory consumption: 45.56G

Link: https://lore.kernel.org/r/71e7a2c017dbc46bb497857ec97d67214f832d10.1685464332.git.jpoimboe@kernel.org


Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent e0a9349b

tools/objtool/elf.c

+13 −19
Original line number Diff line number Diff line
@@ -293,7 +293,6 @@ static int read_sections(struct elf *elf) 
		sec = &elf->section_data[i];



		INIT_LIST_HEAD(&sec->symbol_list);

		INIT_LIST_HEAD(&sec->reloc_list);



		s = elf_getscn(elf->elf, i);

		if (!s) {
@@ -333,7 +332,7 @@ static int read_sections(struct elf *elf) 
		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;

			elf->num_relocs += sec_num_entries(sec);

	}



	if (opts.stats) {
@@ -407,7 +406,7 @@ static int read_symbols(struct elf *elf) 
		if (symtab_shndx)

			shndx_data = symtab_shndx->data;



		symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;

		symbols_nr = sec_num_entries(symtab);

	} else {

		/*

		 * A missing symbol table is actually possible if it's an empty
@@ -701,7 +700,7 @@ __elf_create_symbol(struct elf *elf, struct symbol *sym) 
		return NULL;

	}



	new_idx = symtab->sh.sh_size / symtab->sh.sh_entsize;

	new_idx = sec_num_entries(symtab);



	if (GELF_ST_BIND(sym->sym.st_info) != STB_LOCAL)

		goto non_local;
@@ -816,13 +815,13 @@ static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec, 
{

	struct reloc *reloc, empty = { 0 };



	if (reloc_idx >= rsec->sh.sh_size / elf_rela_size(elf)) {

		WARN("%s: bad reloc_idx %u for %s with size 0x%lx",

		     __func__, reloc_idx, rsec->name, rsec->sh.sh_size);

	if (reloc_idx >= sec_num_entries(rsec)) {

		WARN("%s: bad reloc_idx %u for %s with %d relocs",

		     __func__, reloc_idx, rsec->name, sec_num_entries(rsec));

		return NULL;

	}



	reloc = &rsec->reloc_data[reloc_idx];

	reloc = &rsec->relocs[reloc_idx];



	if (memcmp(reloc, &empty, sizeof(empty))) {

		WARN("%s: %s: reloc %d already initialized!",
@@ -841,7 +840,6 @@ static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec, 
		return NULL;



	list_add_tail(&reloc->sym_reloc_entry, &sym->reloc_list);

	list_add_tail(&reloc->list, &rsec->reloc_list);

	elf_hash_add(reloc, &reloc->hash, reloc_hash(reloc));



	return reloc;
@@ -944,14 +942,13 @@ static int read_relocs(struct elf *elf) 
		rsec->base->rsec = rsec;



		nr_reloc = 0;

		rsec->reloc_data = calloc(rsec->sh.sh_size / rsec->sh.sh_entsize,

					  sizeof(*reloc));

		if (!rsec->reloc_data) {

		rsec->relocs = calloc(sec_num_entries(rsec), sizeof(*reloc));

		if (!rsec->relocs) {

			perror("calloc");

			return -1;

		}

		for (i = 0; i < rsec->sh.sh_size / rsec->sh.sh_entsize; i++) {

			reloc = &rsec->reloc_data[i];

		for (i = 0; i < sec_num_entries(rsec); i++) {

			reloc = &rsec->relocs[i];



			if (read_reloc(rsec, i, reloc))

				return -1;
@@ -967,7 +964,6 @@ static int read_relocs(struct elf *elf) 
			}



			list_add_tail(&reloc->sym_reloc_entry, &sym->reloc_list);

			list_add_tail(&reloc->list, &rsec->reloc_list);

			elf_hash_add(reloc, &reloc->hash, reloc_hash(reloc));



			nr_reloc++;
@@ -1093,7 +1089,6 @@ struct section *elf_create_section(struct elf *elf, const char *name, 
	memset(sec, 0, sizeof(*sec));



	INIT_LIST_HEAD(&sec->symbol_list);

	INIT_LIST_HEAD(&sec->reloc_list);



	s = elf_newscn(elf->elf);

	if (!s) {
@@ -1186,9 +1181,8 @@ static struct section *elf_create_rela_section(struct elf *elf, 
	rsec->sh.sh_info = sec->idx;

	rsec->sh.sh_flags = SHF_INFO_LINK;



	rsec->reloc_data = calloc(rsec->sh.sh_size / rsec->sh.sh_entsize,

				  sizeof(struct reloc));

	if (!rsec->reloc_data) {

	rsec->relocs = calloc(sec_num_entries(rsec), sizeof(struct reloc));

	if (!rsec->relocs) {

		perror("calloc");

		return NULL;

	}

tools/objtool/include/objtool/elf.h

+13 −5
Original line number Diff line number Diff line
@@ -33,14 +33,13 @@ struct section { 
	GElf_Shdr sh;

	struct rb_root_cached symbol_tree;

	struct list_head symbol_list;

	struct list_head reloc_list;

	struct section *base, *rsec;

	struct symbol *sym;

	Elf_Data *data;

	char *name;

	int idx;

	bool _changed, text, rodata, noinstr, init, truncate;

	struct reloc *reloc_data;

	struct reloc *relocs;

};



struct symbol {
@@ -68,7 +67,6 @@ struct symbol { 
};



struct reloc {

	struct list_head list;

	struct hlist_node hash;

	union {

		GElf_Rela rela;
@@ -197,6 +195,11 @@ static inline void mark_sec_changed(struct elf *elf, struct section *sec, 
	elf->changed |= changed;

}



static inline unsigned int sec_num_entries(struct section *sec)

{

	return sec->sh.sh_size / sec->sh.sh_entsize;

}



#define for_each_sec(file, sec)						\

	list_for_each_entry(sec, &file->elf->sections, list)
@@ -210,10 +213,15 @@ static inline void mark_sec_changed(struct elf *elf, struct section *sec, 
			sec_for_each_sym(__sec, sym)



#define for_each_reloc(rsec, reloc)					\

	list_for_each_entry(reloc, &rsec->reloc_list, list)

	for (int __i = 0, __fake = 1; __fake; __fake = 0)		\

		for (reloc = rsec->relocs;				\

		     __i < sec_num_entries(rsec);			\

		     __i++, reloc++)



#define for_each_reloc_from(rsec, reloc)				\

	list_for_each_entry_from(reloc, &rsec->reloc_list, list)

	for (int __i = reloc->idx;					\

	     __i < sec_num_entries(rsec);				\

	     __i++, reloc++)



#define OFFSET_STRIDE_BITS	4

#define OFFSET_STRIDE		(1UL << OFFSET_STRIDE_BITS)