Emit unwinding information for TurboFan code.

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

+// 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) {
+  block_will_exit_ = false;
+
+  auto lookup = block_initial_states_.find(block->rpo_number().ToInt());
+  if (lookup != block_initial_states_.end()) {
+    if (!lookup->second.register_.is(eh_frame_writer_.base_register()) &&
+        lookup->second.offset_ != eh_frame_writer_.base_offset()) {
+      eh_frame_writer_.AdvanceLocation(pc_offset);
+      eh_frame_writer_.SetBaseAddressRegisterAndOffset(lookup->second.register_,
+                                                       lookup->second.offset_);
+    } else if (!lookup->second.register_.is(eh_frame_writer_.base_register())) {
+      eh_frame_writer_.AdvanceLocation(pc_offset);
+      eh_frame_writer_.SetBaseAddressRegister(lookup->second.register_);
+    } else if (lookup->second.offset_ != eh_frame_writer_.base_offset()) {
+      eh_frame_writer_.AdvanceLocation(pc_offset);
+      eh_frame_writer_.SetBaseAddressOffset(lookup->second.offset_);
+    }
+
+    tracking_fp_ = lookup->second.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 (block_will_exit_) return;
+
+  for (const RpoNumber& successor : block->successors()) {
+    BlockInitialState state = {eh_frame_writer_.base_register(),
+                               eh_frame_writer_.base_offset(), tracking_fp_};
+    auto inserted = block_initial_states_.insert({successor.ToInt(), state});
+    // If we already had an entry for this BB, check that the values are the
+    // same we were trying to insert.
+    if (!inserted.second) {
+      DCHECK(inserted.first->second.register_.is(state.register_));
+      DCHECK_EQ(inserted.first->second.offset_, state.offset_);
+      DCHECK_EQ(inserted.first->second.tracking_fp_, state.tracking_fp_);
+    }
+  }
+}
+
+void UnwindingInfoWriter::MarkFrameConstructed(int pc_base) {
+  // push rbp
+  eh_frame_writer_.AdvanceLocation(pc_base + 1);
+  eh_frame_writer_.IncreaseBaseAddressOffset(kInt64Size);
+  eh_frame_writer_.RecordRegisterSavedToStack(rbp);
+
+  // mov rbp, rsp
+  eh_frame_writer_.AdvanceLocation(pc_base + 4);
+  eh_frame_writer_.SetBaseAddressRegister(rbp);
+
+  tracking_fp_ = true;
+}
+
+void UnwindingInfoWriter::MarkFrameDeconstructed(int pc_base) {
+  // 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