1 files changed, 59 insertions, 4 deletions

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index c1c338661699..7ec85d567598 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -79,6 +79,19 @@ struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset)
 	return NULL;
 }
 
+struct symbol *find_symbol_by_name(struct elf *elf, const char *name)
+{
+	struct section *sec;
+	struct symbol *sym;
+
+	list_for_each_entry(sec, &elf->sections, list)
+		list_for_each_entry(sym, &sec->symbol_list, list)
+			if (!strcmp(sym->name, name))
+				return sym;
+
+	return NULL;
+}
+
 struct symbol *find_symbol_containing(struct section *sec, unsigned long offset)
 {
 	struct symbol *sym;
@@ -203,10 +216,11 @@ static int read_sections(struct elf *elf)
 
 static int read_symbols(struct elf *elf)
 {
-	struct section *symtab;
-	struct symbol *sym;
+	struct section *symtab, *sec;
+	struct symbol *sym, *pfunc;
 	struct list_head *entry, *tmp;
 	int symbols_nr, i;
+	char *coldstr;
 
 	symtab = find_section_by_name(elf, ".symtab");
 	if (!symtab) {
@@ -281,6 +295,45 @@ static int read_symbols(struct elf *elf)
 		hash_add(sym->sec->symbol_hash, &sym->hash, sym->idx);
 	}
 
+	/* Create parent/child links for any cold subfunctions */
+	list_for_each_entry(sec, &elf->sections, list) {
+		list_for_each_entry(sym, &sec->symbol_list, list) {
+			if (sym->type != STT_FUNC)
+				continue;
+			sym->pfunc = sym->cfunc = sym;
+			coldstr = strstr(sym->name, ".cold.");
+			if (!coldstr)
+				continue;
+
+			coldstr[0] = '\0';
+			pfunc = find_symbol_by_name(elf, sym->name);
+			coldstr[0] = '.';
+
+			if (!pfunc) {
+				WARN("%s(): can't find parent function",
+				     sym->name);
+				goto err;
+			}
+
+			sym->pfunc = pfunc;
+			pfunc->cfunc = sym;
+
+			/*
+			 * Unfortunately, -fnoreorder-functions puts the child
+			 * inside the parent.  Remove the overlap so we can
+			 * have sane assumptions.
+			 *
+			 * Note that pfunc->len now no longer matches
+			 * pfunc->sym.st_size.
+			 */
+			if (sym->sec == pfunc->sec &&
+			    sym->offset >= pfunc->offset &&
+			    sym->offset + sym->len == pfunc->offset + pfunc->len) {
+				pfunc->len -= sym->len;
+			}
+		}
+	}
+
 	return 0;
 
 err:
@@ -466,10 +519,12 @@ struct section *elf_create_section(struct elf *elf, const char *name,
 	sec->sh.sh_flags = SHF_ALLOC;
 
 
-	/* Add section name to .shstrtab */
+	/* Add section name to .shstrtab (or .strtab for Clang) */
 	shstrtab = find_section_by_name(elf, ".shstrtab");
+	if (!shstrtab)
+		shstrtab = find_section_by_name(elf, ".strtab");
 	if (!shstrtab) {
-		WARN("can't find .shstrtab section");
+		WARN("can't find .shstrtab or .strtab section");
 		return NULL;
 	}