Allow reading just CFI data when reading symbols

R=thestig at https://breakpad.appspot.com/517002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1124 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 104 insertions, 93 deletions

diff --git a/src/common/linux/dump_symbols.cc b/src/common/linux/dump_symbols.cc
index fed27b7a..f2d42660 100644
--- a/src/common/linux/dump_symbols.cc
+++ b/src/common/linux/dump_symbols.cc
@@ -515,6 +515,7 @@ bool LoadSymbols(const string& obj_file,
                  const typename ElfClass::Ehdr* elf_header,
                  const bool read_gnu_debug_link,
                  LoadSymbolsInfo<ElfClass>* info,
+                 SymbolData symbol_data,
                  Module* module) {
   typedef typename ElfClass::Addr Addr;
   typedef typename ElfClass::Phdr Phdr;
@@ -535,81 +536,85 @@ bool LoadSymbols(const string& obj_file,
   bool found_debug_info_section = false;
   bool found_usable_info = false;
 
-  // Look for STABS debugging information, and load it if present.
-  const Shdr* stab_section =
+  if (symbol_data != ONLY_CFI) {
+    // Look for STABS debugging information, and load it if present.
+    const Shdr* stab_section =
       FindElfSectionByName<ElfClass>(".stab", SHT_PROGBITS,
                                      sections, names, names_end,
                                      elf_header->e_shnum);
-  if (stab_section) {
-    const Shdr* stabstr_section = stab_section->sh_link + sections;
-    if (stabstr_section) {
-      found_debug_info_section = true;
-      found_usable_info = true;
-      info->LoadedSection(".stab");
-      if (!LoadStabs<ElfClass>(elf_header, stab_section, stabstr_section,
-                               big_endian, module)) {
-        fprintf(stderr, "%s: \".stab\" section found, but failed to load STABS"
-                " debugging information\n", obj_file.c_str());
+    if (stab_section) {
+      const Shdr* stabstr_section = stab_section->sh_link + sections;
+      if (stabstr_section) {
+        found_debug_info_section = true;
+        found_usable_info = true;
+        info->LoadedSection(".stab");
+        if (!LoadStabs<ElfClass>(elf_header, stab_section, stabstr_section,
+                                 big_endian, module)) {
+          fprintf(stderr, "%s: \".stab\" section found, but failed to load"
+                  " STABS debugging information\n", obj_file.c_str());
+        }
       }
     }
-  }
 
-  // Look for DWARF debugging information, and load it if present.
-  const Shdr* dwarf_section =
+    // Look for DWARF debugging information, and load it if present.
+    const Shdr* dwarf_section =
       FindElfSectionByName<ElfClass>(".debug_info", SHT_PROGBITS,
                                      sections, names, names_end,
                                      elf_header->e_shnum);
-  if (dwarf_section) {
-    found_debug_info_section = true;
-    found_usable_info = true;
-    info->LoadedSection(".debug_info");
-    if (!LoadDwarf<ElfClass>(obj_file, elf_header, big_endian, module))
-      fprintf(stderr, "%s: \".debug_info\" section found, but failed to load "
-              "DWARF debugging information\n", obj_file.c_str());
-  }
-
-  // Dwarf Call Frame Information (CFI) is actually independent from
-  // the other DWARF debugging information, and can be used alone.
-  const Shdr* dwarf_cfi_section =
-      FindElfSectionByName<ElfClass>(".debug_frame", SHT_PROGBITS,
-                                     sections, names, names_end,
-                                     elf_header->e_shnum);
-  if (dwarf_cfi_section) {
-    // Ignore the return value of this function; even without call frame
-    // information, the other debugging information could be perfectly
-    // useful.
-    info->LoadedSection(".debug_frame");
-    bool result =
-        LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".debug_frame",
-                               dwarf_cfi_section, false, 0, 0, big_endian,
-                               module);
-    found_usable_info = found_usable_info || result;
-  }
-
-  // Linux C++ exception handling information can also provide
-  // unwinding data.
-  const Shdr* eh_frame_section =
-      FindElfSectionByName<ElfClass>(".eh_frame", SHT_PROGBITS,
-                                     sections, names, names_end,
-                                     elf_header->e_shnum);
-  if (eh_frame_section) {
-    // Pointers in .eh_frame data may be relative to the base addresses of
-    // certain sections. Provide those sections if present.
-    const Shdr* got_section =
-        FindElfSectionByName<ElfClass>(".got", SHT_PROGBITS,
+    if (dwarf_section) {
+      found_debug_info_section = true;
+      found_usable_info = true;
+      info->LoadedSection(".debug_info");
+      if (!LoadDwarf<ElfClass>(obj_file, elf_header, big_endian, module))
+        fprintf(stderr, "%s: \".debug_info\" section found, but failed to load "
+                "DWARF debugging information\n", obj_file.c_str());
+    }
+  }
+
+  if (symbol_data != NO_CFI) {
+    // Dwarf Call Frame Information (CFI) is actually independent from
+    // the other DWARF debugging information, and can be used alone.
+    const Shdr* dwarf_cfi_section =
+        FindElfSectionByName<ElfClass>(".debug_frame", SHT_PROGBITS,
                                        sections, names, names_end,
                                        elf_header->e_shnum);
-    const Shdr* text_section =
-        FindElfSectionByName<ElfClass>(".text", SHT_PROGBITS,
+    if (dwarf_cfi_section) {
+      // Ignore the return value of this function; even without call frame
+      // information, the other debugging information could be perfectly
+      // useful.
+      info->LoadedSection(".debug_frame");
+      bool result =
+          LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".debug_frame",
+                                 dwarf_cfi_section, false, 0, 0, big_endian,
+                                 module);
+      found_usable_info = found_usable_info || result;
+    }
+
+    // Linux C++ exception handling information can also provide
+    // unwinding data.
+    const Shdr* eh_frame_section =
+        FindElfSectionByName<ElfClass>(".eh_frame", SHT_PROGBITS,
                                        sections, names, names_end,
                                        elf_header->e_shnum);
-    info->LoadedSection(".eh_frame");
-    // As above, ignore the return value of this function.
-    bool result =
-        LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".eh_frame",
-                               eh_frame_section, true,
-                               got_section, text_section, big_endian, module);
-    found_usable_info = found_usable_info || result;
+    if (eh_frame_section) {
+      // Pointers in .eh_frame data may be relative to the base addresses of
+      // certain sections. Provide those sections if present.
+      const Shdr* got_section =
+          FindElfSectionByName<ElfClass>(".got", SHT_PROGBITS,
+                                         sections, names, names_end,
+                                         elf_header->e_shnum);
+      const Shdr* text_section =
+          FindElfSectionByName<ElfClass>(".text", SHT_PROGBITS,
+                                         sections, names, names_end,
+                                         elf_header->e_shnum);
+      info->LoadedSection(".eh_frame");
+      // As above, ignore the return value of this function.
+      bool result =
+          LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".eh_frame",
+                                 eh_frame_section, true,
+                                 got_section, text_section, big_endian, module);
+      found_usable_info = found_usable_info || result;
+    }
   }
 
   if (!found_debug_info_section) {
@@ -642,32 +647,36 @@ bool LoadSymbols(const string& obj_file,
                 obj_file.c_str());
       }
     } else {
-      // The caller doesn't want to consult .gnu_debuglink.
-      // See if there are export symbols available.
-      const Shdr* dynsym_section =
+      if (symbol_data != ONLY_CFI) {
+        // The caller doesn't want to consult .gnu_debuglink.
+        // 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 =
+        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;
+        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;
+        }
       }
 
       // Return true if some usable information was found, since
@@ -736,7 +745,7 @@ template<typename ElfClass>
 bool ReadSymbolDataElfClass(const typename ElfClass::Ehdr* elf_header,
                              const string& obj_filename,
                              const std::vector<string>& debug_dirs,
-                             bool cfi,
+                             SymbolData symbol_data,
                              Module** out_module) {
   typedef typename ElfClass::Ehdr Ehdr;
   typedef typename ElfClass::Shdr Shdr;
@@ -770,7 +779,8 @@ bool ReadSymbolDataElfClass(const typename ElfClass::Ehdr* elf_header,
   LoadSymbolsInfo<ElfClass> info(debug_dirs);
   scoped_ptr<Module> module(new Module(name, os, architecture, id));
   if (!LoadSymbols<ElfClass>(obj_filename, big_endian, elf_header,
-                             !debug_dirs.empty(), &info, module.get())) {
+                             !debug_dirs.empty(), &info,
+                             symbol_data, module.get())) {
     const string debuglink_file = info.debuglink_file();
     if (debuglink_file.empty())
       return false;
@@ -808,7 +818,8 @@ bool ReadSymbolDataElfClass(const typename ElfClass::Ehdr* elf_header,
     }
 
     if (!LoadSymbols<ElfClass>(debuglink_file, debug_big_endian,
-                               debug_elf_header, false, &info, module.get())) {
+                               debug_elf_header, false, &info,
+                               symbol_data, module.get())) {
       return false;
     }
   }
@@ -825,7 +836,7 @@ namespace google_breakpad {
 bool ReadSymbolDataInternal(const uint8_t* obj_file,
                             const string& obj_filename,
                             const std::vector<string>& debug_dirs,
-                            bool cfi,
+                            SymbolData symbol_data,
                             Module** module) {
 
   if (!IsValidElf(obj_file)) {
@@ -837,12 +848,12 @@ bool ReadSymbolDataInternal(const uint8_t* obj_file,
   if (elfclass == ELFCLASS32) {
     return ReadSymbolDataElfClass<ElfClass32>(
         reinterpret_cast<const Elf32_Ehdr*>(obj_file), obj_filename, debug_dirs,
-        cfi, module);
+        symbol_data, module);
   }
   if (elfclass == ELFCLASS64) {
     return ReadSymbolDataElfClass<ElfClass64>(
         reinterpret_cast<const Elf64_Ehdr*>(obj_file), obj_filename, debug_dirs,
-        cfi, module);
+        symbol_data, module);
   }
 
   return false;
@@ -850,20 +861,20 @@ bool ReadSymbolDataInternal(const uint8_t* obj_file,
 
 bool WriteSymbolFile(const string &obj_file,
                      const std::vector<string>& debug_dirs,
-                     bool cfi,
+                     SymbolData symbol_data,
                      std::ostream &sym_stream) {
   Module* module;
-  if (!ReadSymbolData(obj_file, debug_dirs, cfi, &module))
+  if (!ReadSymbolData(obj_file, debug_dirs, symbol_data, &module))
     return false;
 
-  bool result = module->Write(sym_stream, cfi);
+  bool result = module->Write(sym_stream, symbol_data);
   delete module;
   return result;
 }
 
 bool ReadSymbolData(const string& obj_file,
                     const std::vector<string>& debug_dirs,
-                    bool cfi,
+                    SymbolData symbol_data,
                     Module** module) {
   MmapWrapper map_wrapper;
   void* elf_header = NULL;
@@ -871,7 +882,7 @@ bool ReadSymbolData(const string& obj_file,
     return false;
 
   return ReadSymbolDataInternal(reinterpret_cast<uint8_t*>(elf_header),
-                                obj_file, debug_dirs, cfi, module);
+                                obj_file, debug_dirs, symbol_data, module);
 }
 
 }  // namespace google_breakpad