[debugger,interpreter] add source position to stack checks.

DevTools uses the debug interrupt to trap on function entry. Without
source position at the stack check, we would get bogus source positions.

R=mstarzinger@chromium.org
BUG=chromium:595646
LOG=N

Review-Url: https://codereview.chromium.org/1925063002
Cr-Commit-Position: refs/heads/master@{#35864}

src/interpreter/bytecode-array-builder.cc

@@ -860,7 +860,13 @@ BytecodeArrayBuilder& BytecodeArrayBuilder::JumpIfUndefined(
   return OutputJump(Bytecode::kJumpIfUndefined, label);
 }
 
-BytecodeArrayBuilder& BytecodeArrayBuilder::StackCheck() {
+BytecodeArrayBuilder& BytecodeArrayBuilder::StackCheck(int position) {
+  if (position != RelocInfo::kNoPosition) {
+    // We need to attach a non-breakable source position to a stack check,
+    // so we simply add it as expression position.
+    source_position_table_builder_.AddExpressionPosition(bytecodes_.size(),
+                                                         position);
+  }
   Output(Bytecode::kStackCheck);
   return *this;
 }

src/interpreter/bytecode-array-builder.h

@@ -223,7 +223,7 @@ class BytecodeArrayBuilder final : public ZoneObject {
   BytecodeArrayBuilder& JumpIfNull(BytecodeLabel* label);
   BytecodeArrayBuilder& JumpIfUndefined(BytecodeLabel* label);
 
-  BytecodeArrayBuilder& StackCheck();
+  BytecodeArrayBuilder& StackCheck(int position);
 
   BytecodeArrayBuilder& Throw();
   BytecodeArrayBuilder& ReThrow();

src/interpreter/bytecode-generator.cc

@@ -638,7 +638,7 @@ void BytecodeGenerator::MakeBytecodeBody() {
   VisitDeclarations(scope()->declarations());
 
   // Perform a stack-check before the body.
-  builder()->StackCheck();
+  builder()->StackCheck(info()->literal()->start_position());
 
   // Visit statements in the function body.
   VisitStatements(info()->literal()->body());
@@ -1036,7 +1036,7 @@ void BytecodeGenerator::VisitCaseClause(CaseClause* clause) {
 void BytecodeGenerator::VisitIterationBody(IterationStatement* stmt,
                                            LoopBuilder* loop_builder) {
   ControlScopeForIteration execution_control(this, stmt, loop_builder);
-  builder()->StackCheck();
+  builder()->StackCheck(stmt->position());
   Visit(stmt->body());
 }
 

test/mjsunit/debug-stack-check-position.js

+// 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.
+
+// Flags: --expose-debug-as debug --allow-natives-syntax
+
+var Debug = debug.Debug;
+var exception = null;
+var loop = true;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    assertTrue(exec_state.frame(0).sourceLineText().indexOf("BREAK") > 0);
+  } catch (e) {
+    exception = e;
+  }
+}
+
+function f() {     // BREAK
+  return 1;
+}
+
+Debug.setListener(listener);
+
+%ScheduleBreak();  // Break on function entry.
+f();
+
+Debug.setListener(null);
+assertNull(exception);

test/unittests/interpreter/bytecode-array-builder-unittest.cc

@@ -208,7 +208,7 @@ TEST_F(BytecodeArrayBuilderTest, AllBytecodesGenerated) {
       .JumpIfFalse(&start);
 
   // Emit stack check bytecode.
-  builder.StackCheck();
+  builder.StackCheck(0);
 
   // Emit throw and re-throw in it's own basic block so that the rest of the
   // code isn't omitted due to being dead.