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

base/profiler/win32_stack_frame_unwinder.h

+// 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.
+
+#ifndef BASE_PROFILER_WIN32_STACK_FRAME_UNWINDER_H_
+#define BASE_PROFILER_WIN32_STACK_FRAME_UNWINDER_H_
+
+#include <windows.h>
+
+#include "base/base_export.h"
+#include "base/macros.h"
+
+namespace base {
+
+#if !defined(_WIN64)
+// Allows code to compile for x86. Actual support for x86 will require either
+// refactoring these interfaces or separate architecture-specific interfaces.
+using PRUNTIME_FUNCTION = void*;
+#endif  // !defined(_WIN64)
+
+// Instances of this class are expected to be created and destroyed for each
+// stack unwinding, outside of SuspendThread/ResumeThread.
+class BASE_EXPORT Win32StackFrameUnwinder {
+ public:
+  // Interface for Win32 unwind-related functionality this class depends
+  // on. Provides a seam for testing.
+  class BASE_EXPORT UnwindFunctions {
+   public:
+    virtual ~UnwindFunctions();
+
+    virtual PRUNTIME_FUNCTION LookupFunctionEntry(DWORD64 program_counter,
+                                                  PDWORD64 image_base) = 0;
+    virtual void VirtualUnwind(DWORD64 image_base,
+                               DWORD64 program_counter,
+                               PRUNTIME_FUNCTION runtime_function,
+                               CONTEXT* context) = 0;
+   protected:
+    UnwindFunctions();
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(UnwindFunctions);
+  };
+
+  class BASE_EXPORT Win32UnwindFunctions : public UnwindFunctions {
+   public:
+    Win32UnwindFunctions();
+
+    virtual PRUNTIME_FUNCTION LookupFunctionEntry(DWORD64 program_counter,
+                                                  PDWORD64 image_base) override;
+
+    virtual void VirtualUnwind(DWORD64 image_base, DWORD64 program_counter,
+                               PRUNTIME_FUNCTION runtime_function,
+                               CONTEXT* context) override;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Win32UnwindFunctions);
+  };
+
+  Win32StackFrameUnwinder();
+  ~Win32StackFrameUnwinder();
+
+  bool TryUnwind(CONTEXT* context);
+
+ private:
+  // This function is for test purposes only.
+  Win32StackFrameUnwinder(UnwindFunctions* unwind_functions);
+  friend class Win32StackFrameUnwinderTest;
+
+  // State associated with each stack unwinding.
+  bool at_top_frame_;
+  bool unwind_info_present_for_all_frames_;
+  const void* pending_blacklisted_module_;
+
+  Win32UnwindFunctions win32_unwind_functions_;
+  UnwindFunctions* const unwind_functions_;
+
+  DISALLOW_COPY_AND_ASSIGN(Win32StackFrameUnwinder);
+};
+
+}  // namespace base
+
+#endif  // BASE_PROFILER_WIN32_STACK_FRAME_UNWINDER_H_