Port some more code to x64

syzygy/agent/common/stack_walker_x86.h

-// Copyright 2015 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-// Defines an X86 stack walker for standard frames that contain a saved EBP
-// value at the top, generated by the common preamble:
-//
-//   push ebp      // Save the previous EBP. ESP now points at the saved EBP.
-//   mov ebp, esp  // EBP now points at the saved EBP.
-//
-// The algorithms expects the stack to be laid out as follows:
-//
-// +-------------+  <-- top of stack
-// | ...data.... |
-// | ret address |
-// +-------------+
-// |  saved ebp  |
-// | ...data.... |  <-- frame 0 (root)
-// | ret address |
-// +-------------+
-// |  saved ebp  |
-// | ...data.... |  <-- frame 1
-// | ret address |
-// +-------------+
-// .      .      .
-// .      .      .
-// +-------------+
-// |  saved ebp  |
-// | ...data.... |  <-- frame n (leaf)
-// | ret address |
-// +-------------+  <-- bottom of stack
-//
-// If the stack is truly laid out as above then there are a few invariants that
-// must hold:
-//
-// - The return address of the previous frame is at EBP + 4. This must be a
-//   sensible return address (non-null, and not in the stack itself).
-// - Frames are laid out linearly on the stack, so successive EBP values must
-//   be monotonically increasing.
-// - Push aligns the stack to the machine word size, so all EBP values must be
-//   4-byte aligned.
-// - There must be the content of the saved EBP and a return pointer between
-//   any two successive EBP values, so they must be at least 8 bytes apart.
-// - The frames must be entirely contained within the stack itself, so strictly
-//   between the known bottom and top of the stack.
-//
-// The algorithm walks the stack as far as it can while the above invariants
-// hold true, saving the value of the return pointer for each valid frame
-// encountered. Note that it can quickly derail if frame pointer optimization
-// is enabled, or at any frame that uses a non-standard layout.
-
-#ifndef SYZYGY_AGENT_COMMON_STACK_WALKER_X86_H_
-#define SYZYGY_AGENT_COMMON_STACK_WALKER_X86_H_
-
-#include "syzygy/common/asan_parameters.h"
-
-namespace agent {
-namespace common {
-
-using StackId = ::common::AsanStackId;
-
-// Heuristically walks the current stack. Does not consider its own stack
-// frame. Frames are expected to have a standard layout with the top of the
-// frame being a saved frame pointer, and the bottom of a frame being a return
-// address.
-// @param bottom_frames_to_skip The number of frames to skip from the bottom
-//     of the stack.
-// @param max_frame_count The maximum number of frames that can be written to
-//     @p frames.
-// @param frames The array to be populated with the computed frames.
-// @param absolute_stack_id Pointer to the stack ID that will be calculated as
-//     we are walking the stack.
-// @returns the number of frames successfully walked and stored in @p frames.
-size_t WalkStack(size_t bottom_frames_to_skip,
-                 size_t max_frame_count,
-                 void** frames,
-                 StackId* absolute_stack_id);
-
-// Implementation of WalkStack, with explicitly provided @p current_ebp,
-// @p stack_bottom and @p stack_top. Exposed for much easier unittesting.
-// @param current_ebp The current stack frame base to start walking from.
-//     This must be a valid stack location from which to start walking.
-// @param stack_bottom The bottom of the stack to walk. (Lower address.)
-// @param stack_top The top of the stack to walk. (Higher address.)
-// @param bottom_frames_to_skip The number of frames to skip from the bottom
-//     of the stack.
-// @param max_frame_count The maximum number of frames that can be written to
-//     @p frames.
-// @param frames The array to be populated with the computed frames.
-// @param absolute_stack_id Pointer to the stack ID that will be calculated as
-//     we are walking the stack.
-// @returns the number of frames successfully walked and stored in @p frames.
-size_t WalkStackImpl(const void* current_ebp,
-                     const void* stack_bottom,
-                     const void* stack_top,
-                     size_t bottom_frames_to_skip,
-                     size_t max_frame_count,
-                     void** frames,
-                     StackId* absolute_stack_id);
-
-}  // namespace common
-}  // namespace agent
-
-#endif  // SYZYGY_AGENT_COMMON_STACK_WALKER_X86_H_