Update Files

v8/include/v8-unwinder.h

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+// Copyright 2021 the V8 project 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 INCLUDE_V8_UNWINDER_H_
+#define INCLUDE_V8_UNWINDER_H_
+
+#include <memory>
+
+#include "v8-embedder-state-scope.h"  // NOLINT(build/include_directory)
+#include "v8config.h"                 // NOLINT(build/include_directory)
+
+namespace v8 {
+// Holds the callee saved registers needed for the stack unwinder. It is the
+// empty struct if no registers are required. Implemented in
+// include/v8-unwinder-state.h.
+struct CalleeSavedRegisters;
+
+// A RegisterState represents the current state of registers used
+// by the sampling profiler API.
+struct V8_EXPORT RegisterState {
+  RegisterState();
+  ~RegisterState();
+  RegisterState(const RegisterState& other);
+  RegisterState& operator=(const RegisterState& other);
+
+  void* pc;  // Instruction pointer.
+  void* sp;  // Stack pointer.
+  void* fp;  // Frame pointer.
+  void* lr;  // Link register (or nullptr on platforms without a link register).
+  // Callee saved registers (or null if no callee saved registers were stored)
+  std::unique_ptr<CalleeSavedRegisters> callee_saved;
+};
+
+// A StateTag represents a possible state of the VM.
+enum StateTag : int {
+  JS,
+  GC,
+  PARSER,
+  BYTECODE_COMPILER,
+  COMPILER,
+  OTHER,
+  EXTERNAL,
+  ATOMICS_WAIT,
+  IDLE
+};
+
+// The output structure filled up by GetStackSample API function.
+struct SampleInfo {
+  size_t frames_count;              // Number of frames collected.
+  void* external_callback_entry;    // External callback address if VM is
+                                    // executing an external callback.
+  void* context;                    // Incumbent native context address.
+  void* embedder_context;           // Native context address for embedder state
+  StateTag vm_state;                // Current VM state.
+  EmbedderStateTag embedder_state;  // Current Embedder state
+};
+
+struct MemoryRange {
+  const void* start = nullptr;
+  size_t length_in_bytes = 0;
+};
+
+struct JSEntryStub {
+  MemoryRange code;
+};
+
+struct JSEntryStubs {
+  JSEntryStub js_entry_stub;
+  JSEntryStub js_construct_entry_stub;
+  JSEntryStub js_run_microtasks_entry_stub;
+};
+
+/**
+ * Various helpers for skipping over V8 frames in a given stack.
+ *
+ * The unwinder API is only supported on the x64, ARM64 and ARM32 architectures.
+ */
+class V8_EXPORT Unwinder {
+ public:
+  /**
+   * Attempt to unwind the stack to the most recent C++ frame. This function is
+   * signal-safe and does not access any V8 state and thus doesn't require an
+   * Isolate.
+   *
+   * The unwinder needs to know the location of the JS Entry Stub (a piece of
+   * code that is run when C++ code calls into generated JS code). This is used
+   * for edge cases where the current frame is being constructed or torn down
+   * when the stack sample occurs.
+   *
+   * The unwinder also needs the virtual memory range of all possible V8 code
+   * objects. There are two ranges required - the heap code range and the range
+   * for code embedded in the binary.
+   *
+   * Available on x64, ARM64 and ARM32.
+   *
+   * \param code_pages A list of all of the ranges in which V8 has allocated
+   * executable code. The caller should obtain this list by calling
+   * Isolate::CopyCodePages() during the same interrupt/thread suspension that
+   * captures the stack.
+   * \param register_state The current registers. This is an in-out param that
+   * will be overwritten with the register values after unwinding, on success.
+   * \param stack_base The resulting stack pointer and frame pointer values are
+   * bounds-checked against the stack_base and the original stack pointer value
+   * to ensure that they are valid locations in the given stack. If these values
+   * or any intermediate frame pointer values used during unwinding are ever out
+   * of these bounds, unwinding will fail.
+   *
+   * \return True on success.
+   */
+  static bool TryUnwindV8Frames(const JSEntryStubs& entry_stubs,
+                                size_t code_pages_length,
+                                const MemoryRange* code_pages,
+                                RegisterState* register_state,
+                                const void* stack_base);
+
+  /**
+   * Whether the PC is within the V8 code range represented by code_pages.
+   *
+   * If this returns false, then calling UnwindV8Frames() with the same PC
+   * and unwind_state will always fail. If it returns true, then unwinding may
+   * (but not necessarily) be successful.
+   *
+   * Available on x64, ARM64 and ARM32
+   */
+  static bool PCIsInV8(size_t code_pages_length, const MemoryRange* code_pages,
+                       void* pc);
+};
+
+}  // namespace v8
+
+#endif  // INCLUDE_V8_UNWINDER_H_