[Clank SSM]: Inject chrome module into ChromeUnwinderAndroid.

As preparation for NativeUnwinderAndroid, Chrome Module is injected into
ChromeUnwinderAndroid. Module are compared using their addresses.
The chrome module will eventually be created from proc/maps.

Bug: 989102
Change-Id: I3120c4e352fcefef577c4ef9d8c3e7ed7b5a370b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2083439
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747443}

base/profiler/chrome_unwinder_android.cc

@@ -4,102 +4,25 @@
 
 #include "base/profiler/chrome_unwinder_android.h"
 
-#include "base/android/library_loader/anchor_functions.h"
-#include "base/debug/elf_reader.h"
-#include "base/debug/proc_maps_linux.h"
-#include "base/no_destructor.h"
 #include "base/numerics/checked_math.h"
 #include "base/profiler/module_cache.h"
 #include "base/profiler/native_unwinder.h"
-#include "base/profiler/profile_builder.h"
 #include "build/build_config.h"
 
-extern "C" {
-// The address of |__executable_start| gives the start address of the
-// executable or shared library. This value is used to find the offset address
-// of the instruction in binary from PC.
-extern char __executable_start;
-}
-
 namespace base {
 
-namespace {
-
-const std::string& GetChromeModuleId() {
-  static const base::NoDestructor<std::string> build_id([] {
-#if defined(OFFICIAL_BUILD)
-    base::debug::ElfBuildIdBuffer build_id;
-    size_t build_id_length =
-        base::debug::ReadElfBuildId(&__executable_start, true, build_id);
-    DCHECK_GT(build_id_length, 0u);
-    // Append 0 for the age value.
-    return std::string(build_id, build_id_length) + "0";
-#else
-    // Local chromium builds don't have an ELF build-id note. A synthetic
-    // build id is provided. https://crbug.com/870919
-    return std::string("CCCCCCCCDB511330464892F0B600B4D60");
-#endif
-  }());
-  return *build_id;
-}
-
-StringPiece GetChromeLibraryName() {
-  static const StringPiece library_name([] {
-    Optional<StringPiece> library_name =
-        base::debug::ReadElfLibraryName(&__executable_start);
-    DCHECK(library_name);
-    return *library_name;
-  }());
-  return library_name;
-}
-
-class ChromeModule : public ModuleCache::Module {
- public:
-  ChromeModule() : build_id_(GetChromeModuleId()) {}
-  ~ChromeModule() override = default;
-
-  uintptr_t GetBaseAddress() const override {
-    return reinterpret_cast<uintptr_t>(&__executable_start);
-  }
-
-  std::string GetId() const override { return build_id_; }
-
-  FilePath GetDebugBasename() const override {
-    return FilePath(GetChromeLibraryName());
-  }
-
-  // Gets the size of the module.
-  size_t GetSize() const override {
-    return base::android::kEndOfText - GetBaseAddress();
-  }
-
-  // True if this is a native module.
-  bool IsNative() const override { return true; }
-
-  std::string build_id_;
-};
-
-}  // namespace
-
-ChromeUnwinderAndroid::ChromeUnwinderAndroid(const ArmCFITable* cfi_table)
-    : cfi_table_(cfi_table) {
+ChromeUnwinderAndroid::ChromeUnwinderAndroid(
+    const ArmCFITable* cfi_table,
+    const ModuleCache::Module* chrome_module)
+    : cfi_table_(cfi_table), chrome_module_(chrome_module) {
   DCHECK(cfi_table_);
+  DCHECK(chrome_module_);
 }
 
 ChromeUnwinderAndroid::~ChromeUnwinderAndroid() = default;
 
-void ChromeUnwinderAndroid::AddInitialModules(ModuleCache* module_cache) {
-  std::vector<std::unique_ptr<const ModuleCache::Module>> modules;
-  modules.push_back(std::make_unique<ChromeModule>());
-  chrome_module_id_ = modules.back()->GetId();
-  module_cache->UpdateNonNativeModules({}, std::move(modules));
-}
-
 bool ChromeUnwinderAndroid::CanUnwindFrom(const Frame* current_frame) const {
-  // AddNonNativeModules() should be called first.
-  DCHECK(!chrome_module_id_.empty());
-  return current_frame->module &&
-         current_frame->module->GetId() == chrome_module_id_;
+  return current_frame->module == chrome_module_;
 }
 
 UnwindResult ChromeUnwinderAndroid::TryUnwind(RegisterContext* thread_context,
@@ -109,7 +32,6 @@ UnwindResult ChromeUnwinderAndroid::TryUnwind(RegisterContext* thread_context,
   DCHECK(CanUnwindFrom(&stack->back()));
   do {
     const ModuleCache::Module* module = stack->back().module;
-
     uintptr_t pc = RegisterContextInstructionPointer(thread_context);
     DCHECK_GE(pc, module->GetBaseAddress());
     uintptr_t func_addr = pc - module->GetBaseAddress();
@@ -126,11 +48,6 @@ UnwindResult ChromeUnwinderAndroid::TryUnwind(RegisterContext* thread_context,
   return UnwindResult::UNRECOGNIZED_FRAME;
 }
 
-void ChromeUnwinderAndroid::SetExpectedChromeModuleIdForTesting(
-    const std::string& chrome_module_id) {
-  chrome_module_id_ = chrome_module_id;
-}
-
 // static
 bool ChromeUnwinderAndroid::Step(RegisterContext* thread_context,
                                  uintptr_t stack_top,

base/profiler/chrome_unwinder_android.h

@@ -18,15 +18,13 @@ namespace base {
 // Chrome unwinder implementation for Android, using ArmCfiTable.
 class BASE_EXPORT ChromeUnwinderAndroid : public Unwinder {
  public:
-  ChromeUnwinderAndroid(const ArmCFITable* cfi_table);
+  ChromeUnwinderAndroid(const ArmCFITable* cfi_table,
+                        const ModuleCache::Module* chrome_module);
   ~ChromeUnwinderAndroid() override;
   ChromeUnwinderAndroid(const ChromeUnwinderAndroid&) = delete;
   ChromeUnwinderAndroid& operator=(const ChromeUnwinderAndroid&) = delete;
 
-  void SetExpectedChromeModuleIdForTesting(const std::string& chrome_module_id);
-
   // Unwinder:
-  void AddInitialModules(ModuleCache* module_cache) override;
   bool CanUnwindFrom(const Frame* current_frame) const override;
   UnwindResult TryUnwind(RegisterContext* thread_context,
                          uintptr_t stack_top,
@@ -45,7 +43,7 @@ class BASE_EXPORT ChromeUnwinderAndroid : public Unwinder {
                    const ArmCFITable::FrameEntry& entry);
 
   const ArmCFITable* cfi_table_;
-  std::string chrome_module_id_;
+  const ModuleCache::Module* const chrome_module_;
 };
 
 }  // namespace base

base/profiler/chrome_unwinder_android_unittest.cc

@@ -213,8 +213,7 @@ TEST(ChromeUnwinderAndroidTest, CanUnwindFrom) {
   auto non_chrome_module =
       std::make_unique<TestModule>(0x2000, 0x500, "OtherModule");
 
-  ChromeUnwinderAndroid unwinder(cfi_table.get());
-  unwinder.SetExpectedChromeModuleIdForTesting("ChromeModule");
+  ChromeUnwinderAndroid unwinder(cfi_table.get(), chrome_module.get());
 
   Frame chrome_frame{0x1100, chrome_module.get()};
   EXPECT_TRUE(unwinder.CanUnwindFrom(&chrome_frame));
@@ -231,8 +230,7 @@ TEST(ChromeUnwinderAndroidTest, TryUnwind) {
   const ModuleCache::Module* chrome_module = AddNativeModule(
       &module_cache, std::make_unique<TestModule>(0x1000, 0x500));
 
-  ChromeUnwinderAndroid unwinder(cfi_table.get());
-  unwinder.SetExpectedChromeModuleIdForTesting(chrome_module->GetId());
+  ChromeUnwinderAndroid unwinder(cfi_table.get(), chrome_module);
 
   std::vector<uintptr_t> stack_buffer = {
       0xFFFF,
@@ -269,8 +267,7 @@ TEST(ChromeUnwinderAndroidTest, TryUnwindAbort) {
   const ModuleCache::Module* chrome_module = AddNativeModule(
       &module_cache, std::make_unique<TestModule>(0x1000, 0x500));
 
-  ChromeUnwinderAndroid unwinder(cfi_table.get());
-  unwinder.SetExpectedChromeModuleIdForTesting(chrome_module->GetId());
+  ChromeUnwinderAndroid unwinder(cfi_table.get(), chrome_module);
 
   std::vector<uintptr_t> stack_buffer = {
       0xFFFF,
@@ -301,8 +298,7 @@ TEST(ChromeUnwinderAndroidTest, TryUnwindNoData) {
   const ModuleCache::Module* chrome_module = AddNativeModule(
       &module_cache, std::make_unique<TestModule>(0x1000, 0x500));
 
-  ChromeUnwinderAndroid unwinder(cfi_table.get());
-  unwinder.SetExpectedChromeModuleIdForTesting(chrome_module->GetId());
+  ChromeUnwinderAndroid unwinder(cfi_table.get(), chrome_module);
 
   std::vector<uintptr_t> stack_buffer = {0xFFFF};
 
@@ -324,16 +320,4 @@ TEST(ChromeUnwinderAndroidTest, TryUnwindNoData) {
   EXPECT_EQ(std::vector<Frame>({{0x1200, chrome_module}}), stack);
 }
 
-TEST(ChromeUnwinderAndroidTest, AddInitialModules) {
-  auto cfi_table = ArmCFITable::Parse(
-      {reinterpret_cast<const uint8_t*>(cfi_data), sizeof(cfi_data)});
-  ChromeUnwinderAndroid unwinder(cfi_table.get());
-  ModuleCache module_cache;
-  unwinder.AddInitialModules(&module_cache);
-
-  EXPECT_NE(module_cache.GetModuleForAddress(reinterpret_cast<uintptr_t>(
-                &ChromeUnwinderAndroid::StepForTesting)),
-            nullptr);
-}
-
 }  // namespace base