Stack sampling profiler: re-enable stack collection for stacks terminated by leaf functions

base/profiler/win32_stack_frame_unwinder_unittest.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/profiler/win32_stack_frame_unwinder.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+namespace {
+
+class TestUnwindFunctions : public Win32StackFrameUnwinder::UnwindFunctions {
+ public:
+  TestUnwindFunctions();
+
+  PRUNTIME_FUNCTION LookupFunctionEntry(DWORD64 program_counter,
+                                        PDWORD64 image_base) override;
+  void VirtualUnwind(DWORD64 image_base,
+                     DWORD64 program_counter,
+                     PRUNTIME_FUNCTION runtime_function,
+                     CONTEXT* context) override;
+
+  void SetNoUnwindInfoForNextFrame();
+  void SetImageBaseForNextFrame(DWORD64 image_base);
+
+ private:
+  enum { kRuntimeFunctionPointerIncrement = 1, kImageBaseIncrement = 1 << 20 };
+
+  static const PRUNTIME_FUNCTION kNonNullRuntimeFunctionPointer;
+
+  DWORD64 supplied_program_counter_;
+  DWORD64 custom_image_base_;
+  DWORD64 next_image_base_;
+  bool next_lookup_returns_null_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestUnwindFunctions);
+};
+
+// This value is opaque to Win32StackFrameUnwinder.
+const PRUNTIME_FUNCTION TestUnwindFunctions::kNonNullRuntimeFunctionPointer =
+    reinterpret_cast<PRUNTIME_FUNCTION>(8);
+
+TestUnwindFunctions::TestUnwindFunctions()
+    : supplied_program_counter_(0),
+      custom_image_base_(0),
+      next_image_base_(1 << 20),

[Nico, 2015/08/18 23:20:24]

s/1 << 20/kImageBaseIncrement/ (?)

[Mike Wittman, 2015/08/18 23:43:10]

Done.

+      next_lookup_returns_null_(false) {
+}
+
+PRUNTIME_FUNCTION TestUnwindFunctions::LookupFunctionEntry(
+    DWORD64 program_counter,
+    PDWORD64 image_base) {
+  supplied_program_counter_ = program_counter;
+  if (custom_image_base_) {
+    *image_base = custom_image_base_;
+    custom_image_base_ = 0;
+  } else {
+    *image_base = next_image_base_;
+    next_image_base_ += kImageBaseIncrement;
+  }
+  if (next_lookup_returns_null_) {
+    next_lookup_returns_null_ = false;
+    return nullptr;
+  }
+
+  return kNonNullRuntimeFunctionPointer;
+}
+
+void TestUnwindFunctions::VirtualUnwind(DWORD64 image_base,
+                                        DWORD64 program_counter,
+                                        PRUNTIME_FUNCTION runtime_function,
+                                        CONTEXT* context) {
+  EXPECT_EQ(next_image_base_ - kImageBaseIncrement, image_base);
+  EXPECT_EQ(supplied_program_counter_, program_counter);
+  // This function should only be called when LookupFunctionEntry returns a
+  // non-null value.
+  EXPECT_EQ(kNonNullRuntimeFunctionPointer, runtime_function);
+}
+
+void TestUnwindFunctions::SetNoUnwindInfoForNextFrame() {
+  next_lookup_returns_null_ = true;
+}
+
+void TestUnwindFunctions::SetImageBaseForNextFrame(DWORD64 image_base) {
+  next_image_base_ = image_base;
+}
+
+}  // namespace
+
+class Win32StackFrameUnwinderTest : public testing::Test {
+ protected:
+  Win32StackFrameUnwinderTest() {}
+
+  scoped_ptr<Win32StackFrameUnwinder> CreateUnwinder();
+
+  TestUnwindFunctions unwind_functions_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Win32StackFrameUnwinderTest);
+};
+
+scoped_ptr<Win32StackFrameUnwinder>
+Win32StackFrameUnwinderTest::CreateUnwinder() {
+  return make_scoped_ptr(new Win32StackFrameUnwinder(&unwind_functions_));
+}
+
+// Checks the case where all frames have unwind information.
+TEST_F(Win32StackFrameUnwinderTest, FramesWithUnwindInfo) {
+  scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();

[Nico, 2015/08/18 23:20:24]

Can't this just live on the stack? (also below) Then you don't need
CreateUnwinder().

[Mike Wittman, 2015/08/18 23:43:10]

It could, but I believe I'd have to do one of: make the
Win32StackFrameUnwinder(UnwindFunctions*) constructor public, friend every test
function separately, or construct with placement new in
Win32StackFrameUnwinderTest. This seemed like the least bad option.

[Nico, 2015/08/18 23:49:48]

Maybe add a "// This exists so that Win32StackFrameUnwinder's constructor can be
private with a single friend" type of comment above CreateUnwinder then.

[Mike Wittman, 2015/08/18 23:58:18]

Done.

+  CONTEXT context = {0};
+  EXPECT_TRUE(unwinder->TryUnwind(&context));
+  EXPECT_TRUE(unwinder->TryUnwind(&context));
+  EXPECT_TRUE(unwinder->TryUnwind(&context));
+}
+
+// Checks that the CONTEXT's stack pointer gets popped when the top frame has no
+// unwind information.
+TEST_F(Win32StackFrameUnwinderTest, FrameAtTopWithoutUnwindInfo) {
+  scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();
+  CONTEXT context = {0};
+  const DWORD64 original_rsp = 128;
+  context.Rsp = original_rsp;
+  unwind_functions_.SetNoUnwindInfoForNextFrame();
+  EXPECT_TRUE(unwinder->TryUnwind(&context));
+  EXPECT_EQ(original_rsp, context.Rip);
+  EXPECT_EQ(original_rsp + 8, context.Rsp);
+
+  EXPECT_TRUE(unwinder->TryUnwind(&context));
+  EXPECT_TRUE(unwinder->TryUnwind(&context));
+}
+
+// Checks that a frame below the top of the stack with missing unwind info
+// results in blacklisting the module.
+TEST_F(Win32StackFrameUnwinderTest, BlacklistedModule) {
+  const DWORD64 image_base_for_module_with_bad_function = 1024;
+  {
+    // First stack, with a bad function below the top of the stack.
+    scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();
+    CONTEXT context = {0};
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+
+    unwind_functions_.SetNoUnwindInfoForNextFrame();
+    unwind_functions_.SetImageBaseForNextFrame(
+        image_base_for_module_with_bad_function);
+    EXPECT_FALSE(unwinder->TryUnwind(&context));
+  }
+
+  {
+    // Second stack; check that a function at the top of the stack without
+    // unwind info from the previously-seen module is blacklisted.
+    scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();
+    CONTEXT context = {0};
+    unwind_functions_.SetNoUnwindInfoForNextFrame();
+    unwind_functions_.SetImageBaseForNextFrame(
+        image_base_for_module_with_bad_function);
+    EXPECT_FALSE(unwinder->TryUnwind(&context));
+  }
+
+  {
+    // Third stack; check that a function at the top of the stack *with* unwind
+    // info from the previously-seen module is not blacklisted. Then check that
+    // functions below the top of the stack with unwind info are not
+    // blacklisted, regardless of whether they are in the previously-seen
+    // module.
+    scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();
+    CONTEXT context = {0};
+    unwind_functions_.SetImageBaseForNextFrame(
+        image_base_for_module_with_bad_function);
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+
+    unwind_functions_.SetImageBaseForNextFrame(
+        image_base_for_module_with_bad_function);
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+  }
+
+  {
+    // Fourth stack; check that a function at the top of the stack without
+    // unwind info and not from the previously-seen module is not
+    // blacklisted. Then check that functions below the top of the stack with
+    // unwind info are not blacklisted, regardless of whether they are in the
+    // previously-seen module.
+    scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();
+    CONTEXT context = {0};
+    unwind_functions_.SetNoUnwindInfoForNextFrame();
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+
+    unwind_functions_.SetImageBaseForNextFrame(
+        image_base_for_module_with_bad_function);
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+  }
+}
+
+// Checks that a frame below the top of the stack with missing unwind info does
+// not result in blacklisting the module if the first frame also was missing
+// unwind info. This ensures we don't blacklist an innocent module because the
+// first frame was bad but we didn't know it at the time.
+TEST_F(Win32StackFrameUnwinderTest, ModuleFromQuestionableFrameNotBlacklisted) {
+  const DWORD64 image_base_for_questionable_module = 2048;
+  {
+    // First stack, with both the first and second frames missing unwind info.
+    scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();
+    CONTEXT context = {0};
+    unwind_functions_.SetNoUnwindInfoForNextFrame();
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+
+    unwind_functions_.SetNoUnwindInfoForNextFrame();
+    unwind_functions_.SetImageBaseForNextFrame(
+        image_base_for_questionable_module);
+    EXPECT_FALSE(unwinder->TryUnwind(&context));
+  }
+
+  {
+    // Second stack; check that the questionable module was not blacklisted.
+    scoped_ptr<Win32StackFrameUnwinder> unwinder = CreateUnwinder();
+    CONTEXT context = {0};
+    unwind_functions_.SetNoUnwindInfoForNextFrame();
+    unwind_functions_.SetImageBaseForNextFrame(
+        image_base_for_questionable_module);
+    EXPECT_TRUE(unwinder->TryUnwind(&context));
+  }
+}
+
+}  // namespace base