Have dump_syms output the full symbol table.

Some of the symbols in the stack trace are not found in the .dynsym
section but were located in the full symbol table .symtab section
instead. This was causing some of our stack traces to be incomplete or
point to incorrect function names.

Since we only output function names, there are actually not that many
more symbols located in .symtab that aren't in .dynsym. It is better to
simply output all symbols found so our stack traces are complete.

R=mark@chromium.org, thestig@chromium.org
BUG=561447

Review URL: https://codereview.chromium.org/1824063002 .

Patch from David Yen <dyen@chromium.org>.

1 files changed, 47 insertions, 18 deletions

diff --git a/src/common/linux/dump_symbols.cc b/src/common/linux/dump_symbols.cc
index d6c593fa..5d2aac7e 100644
--- a/src/common/linux/dump_symbols.cc
+++ b/src/common/linux/dump_symbols.cc
@@ -684,32 +684,61 @@ bool LoadSymbols(const string& obj_file,
     }
 
     // See if there are export symbols available.
-    const Shdr* dynsym_section =
-      FindElfSectionByName<ElfClass>(".dynsym", SHT_DYNSYM,
-                                     sections, names, names_end,
-                                     elf_header->e_shnum);
-    const Shdr* dynstr_section =
-      FindElfSectionByName<ElfClass>(".dynstr", SHT_STRTAB,
-                                     sections, names, names_end,
-                                     elf_header->e_shnum);
-    if (dynsym_section && dynstr_section) {
-      info->LoadedSection(".dynsym");
+    const Shdr* symtab_section =
+        FindElfSectionByName<ElfClass>(".symtab", SHT_SYMTAB,
+                                       sections, names, names_end,
+                                       elf_header->e_shnum);
+    const Shdr* strtab_section =
+        FindElfSectionByName<ElfClass>(".strtab", SHT_STRTAB,
+                                       sections, names, names_end,
+                                       elf_header->e_shnum);
+    if (symtab_section && strtab_section) {
+      info->LoadedSection(".symtab");
 
-      const uint8_t* dynsyms =
+      const uint8_t* symtab =
           GetOffset<ElfClass, uint8_t>(elf_header,
-                                       dynsym_section->sh_offset);
-      const uint8_t* dynstrs =
+                                       symtab_section->sh_offset);
+      const uint8_t* strtab =
           GetOffset<ElfClass, uint8_t>(elf_header,
-                                       dynstr_section->sh_offset);
+                                       strtab_section->sh_offset);
       bool result =
-          ELFSymbolsToModule(dynsyms,
-                             dynsym_section->sh_size,
-                             dynstrs,
-                             dynstr_section->sh_size,
+          ELFSymbolsToModule(symtab,
+                             symtab_section->sh_size,
+                             strtab,
+                             strtab_section->sh_size,
                              big_endian,
                              ElfClass::kAddrSize,
                              module);
       found_usable_info = found_usable_info || result;
+    } else {
+      // Look in dynsym only if full symbol table was not available.
+      const Shdr* dynsym_section =
+          FindElfSectionByName<ElfClass>(".dynsym", SHT_DYNSYM,
+                                         sections, names, names_end,
+                                         elf_header->e_shnum);
+      const Shdr* dynstr_section =
+          FindElfSectionByName<ElfClass>(".dynstr", SHT_STRTAB,
+                                         sections, names, names_end,
+                                         elf_header->e_shnum);
+      if (dynsym_section && dynstr_section) {
+        info->LoadedSection(".dynsym");
+
+        const uint8_t* dynsyms =
+            GetOffset<ElfClass, uint8_t>(elf_header,
+                                         dynsym_section->sh_offset);
+        const uint8_t* dynstrs =
+            GetOffset<ElfClass, uint8_t>(elf_header,
+                                         dynstr_section->sh_offset);
+        bool result =
+            ELFSymbolsToModule(dynsyms,
+                               dynsym_section->sh_size,
+                               dynstrs,
+                               dynstr_section->sh_size,
+                               big_endian,
+                               ElfClass::kAddrSize,
+                               module);
+        found_usable_info = found_usable_info || result;
+      }
     }
   }