Emit unwinding information for TurboFan code.

src/compiler/x64/unwinding-info-writer-x64.cc

Index: src/compiler/x64/unwinding-info-writer-x64.cc
diff --git a/src/compiler/x64/unwinding-info-writer-x64.cc b/src/compiler/x64/unwinding-info-writer-x64.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4efba3254f16810afd4b7997b9357a287675d476
--- /dev/null
+++ b/src/compiler/x64/unwinding-info-writer-x64.cc
@@ -0,0 +1,102 @@
+// Copyright 2016 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.
+
+#include "src/compiler/x64/unwinding-info-writer-x64.h"
+#include "src/compiler/instruction.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+void UnwindingInfoWriter::BeginInstructionBlock(int pc_offset,
+                                                const InstructionBlock* block) {
+  if (!enabled()) return;
+
+  block_will_exit_ = false;
+
+  DCHECK_LT(block->rpo_number().ToInt(), block_initial_states_.size());
+  const BlockInitialState* initial_state =
+      block_initial_states_[block->rpo_number().ToInt()];
+  if (initial_state) {
+    if (!initial_state->register_.is(eh_frame_writer_.base_register()) &&
+        initial_state->offset_ != eh_frame_writer_.base_offset()) {
+      eh_frame_writer_.AdvanceLocation(pc_offset);
+      eh_frame_writer_.SetBaseAddressRegisterAndOffset(initial_state->register_,
+                                                       initial_state->offset_);
+    } else if (!initial_state->register_.is(eh_frame_writer_.base_register())) {
+      eh_frame_writer_.AdvanceLocation(pc_offset);
+      eh_frame_writer_.SetBaseAddressRegister(initial_state->register_);
+    } else if (initial_state->offset_ != eh_frame_writer_.base_offset()) {
+      eh_frame_writer_.AdvanceLocation(pc_offset);
+      eh_frame_writer_.SetBaseAddressOffset(initial_state->offset_);
+    }
+
+    tracking_fp_ = initial_state->tracking_fp_;
+  } else {
+    // The entry block always lacks an explicit initial state.
+    // The exit block may lack an explicit state, if it is only reached by
+    //   the block ending in a ret.
+    // All the other blocks must have an explicit initial state.
+    DCHECK(block->predecessors().empty() || block->successors().empty());
+  }
+}
+
+void UnwindingInfoWriter::EndInstructionBlock(const InstructionBlock* block) {
+  if (!enabled() || block_will_exit_) return;
+
+  for (const RpoNumber& successor : block->successors()) {
+    int successor_index = successor.ToInt();
+    DCHECK_LT(successor_index, block_initial_states_.size());
+    const BlockInitialState* existing_state =
+        block_initial_states_[successor_index];
+    // If we already had an entry for this BB, check that the values are the
+    // same we are trying to insert.
+    if (existing_state) {
+      DCHECK(existing_state->register_.is(eh_frame_writer_.base_register()));
+      DCHECK_EQ(existing_state->offset_, eh_frame_writer_.base_offset());
+      DCHECK_EQ(existing_state->tracking_fp_, tracking_fp_);
+    } else {
+      block_initial_states_[successor_index] = new (zone_)
+          BlockInitialState(eh_frame_writer_.base_register(),
+                            eh_frame_writer_.base_offset(), tracking_fp_);
+    }
+  }
+}
+
+void UnwindingInfoWriter::MarkFrameConstructed(int pc_base) {
+  if (!enabled()) return;
+
+  // push rbp
+  eh_frame_writer_.AdvanceLocation(pc_base + 1);
+  eh_frame_writer_.IncreaseBaseAddressOffset(kInt64Size);
+  // <base address> points at the bottom of the current frame on x64 and
+  // <base register> is rsp, which points to the top of the frame by definition.
+  // Thus, the distance between <base address> and the top is -<base offset>.
+  int top_of_stack = -eh_frame_writer_.base_offset();
+  eh_frame_writer_.RecordRegisterSavedToStack(rbp, top_of_stack);
+
+  // mov rbp, rsp
+  eh_frame_writer_.AdvanceLocation(pc_base + 4);
+  eh_frame_writer_.SetBaseAddressRegister(rbp);
+
+  tracking_fp_ = true;
+}
+
+void UnwindingInfoWriter::MarkFrameDeconstructed(int pc_base) {
+  if (!enabled()) return;
+
+  // mov rsp, rbp
+  eh_frame_writer_.AdvanceLocation(pc_base + 3);
+  eh_frame_writer_.SetBaseAddressRegister(rsp);
+
+  // pop rbp
+  eh_frame_writer_.AdvanceLocation(pc_base + 4);
+  eh_frame_writer_.IncreaseBaseAddressOffset(-kInt64Size);
+
+  tracking_fp_ = false;
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8