Reland "Fix stepping in for-loops."

BUG=v8:3634
LOG=N
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/688243005

Cr-Commit-Position: refs/heads/master@{#25279}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25279 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/full-codegen-arm.cc

@@ -1111,6 +1111,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
+  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   __ cmp(r0, ip);
@@ -1214,6 +1215,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Generate code for doing the condition check.
   PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ bind(&loop);
+  SetExpressionPosition(stmt->each());
+
   // Load the current count to r0, load the length to r1.
   __ Ldrd(r0, r1, MemOperand(sp, 0 * kPointerSize));
   __ cmp(r0, r1);  // Compare to the array length.
@@ -1283,48 +1286,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
-void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
-  Comment cmnt(masm_, "[ ForOfStatement");
-  SetStatementPosition(stmt);
-
-  Iteration loop_statement(this, stmt);
-  increment_loop_depth();
-
-  // var iterator = iterable[Symbol.iterator]();
-  VisitForEffect(stmt->assign_iterator());
-
-  // Loop entry.
-  __ bind(loop_statement.continue_label());
-
-  // result = iterator.next()
-  VisitForEffect(stmt->next_result());
-
-  // if (result.done) break;
-  Label result_not_done;
-  VisitForControl(stmt->result_done(),
-                  loop_statement.break_label(),
-                  &result_not_done,
-                  &result_not_done);
-  __ bind(&result_not_done);
-
-  // each = result.value
-  VisitForEffect(stmt->assign_each());
-
-  // Generate code for the body of the loop.
-  Visit(stmt->body());
-
-  // Check stack before looping.
-  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
-  __ jmp(loop_statement.continue_label());
-
-  // Exit and decrement the loop depth.
-  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_label());
-  decrement_loop_depth();
-}
-
-
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new

src/arm64/full-codegen-arm64.cc

@@ -1109,6 +1109,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
+  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ JumpIfRoot(x0, Heap::kUndefinedValueRootIndex, &exit);
   Register null_value = x15;
@@ -1202,6 +1203,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Generate code for doing the condition check.
   PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ Bind(&loop);
+  SetExpressionPosition(stmt->each());
+
   // Load the current count to x0, load the length to x1.
   __ PeekPair(x0, x1, 0);
   __ Cmp(x0, x1);  // Compare to the array length.
@@ -1271,48 +1274,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
-void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
-  Comment cmnt(masm_, "[ ForOfStatement");
-  SetStatementPosition(stmt);
-
-  Iteration loop_statement(this, stmt);
-  increment_loop_depth();
-
-  // var iterator = iterable[Symbol.iterator]();
-  VisitForEffect(stmt->assign_iterator());
-
-  // Loop entry.
-  __ Bind(loop_statement.continue_label());
-
-  // result = iterator.next()
-  VisitForEffect(stmt->next_result());
-
-  // if (result.done) break;
-  Label result_not_done;
-  VisitForControl(stmt->result_done(),
-                  loop_statement.break_label(),
-                  &result_not_done,
-                  &result_not_done);
-  __ Bind(&result_not_done);
-
-  // each = result.value
-  VisitForEffect(stmt->assign_each());
-
-  // Generate code for the body of the loop.
-  Visit(stmt->body());
-
-  // Check stack before looping.
-  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
-  __ B(loop_statement.continue_label());
-
-  // Exit and decrement the loop depth.
-  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ Bind(loop_statement.break_label());
-  decrement_loop_depth();
-}
-
-
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new space for

src/full-codegen.cc

@@ -136,21 +136,19 @@ void BreakableStatementChecker::VisitWhileStatement(WhileStatement* stmt) {
 
 
 void BreakableStatementChecker::VisitForStatement(ForStatement* stmt) {
-  // Mark for statements breakable if the condition expression is.
+  // We set positions for both init and condition, if they exist.
-  if (stmt->cond() != NULL) {
+  if (stmt->cond() != NULL || stmt->init() != NULL) is_breakable_ = true;
-    Visit(stmt->cond());
-  }
 }
 
 
 void BreakableStatementChecker::VisitForInStatement(ForInStatement* stmt) {
-  // Mark for in statements breakable if the enumerable expression is.
+  // For-in is breakable because we set the position for the enumerable.
-  Visit(stmt->enumerable());
+  is_breakable_ = true;
 }
 
 
 void BreakableStatementChecker::VisitForOfStatement(ForOfStatement* stmt) {
-  // For-of is breakable because of the next() call.
+  // For-of is breakable because we set the position for the next() call.
   is_breakable_ = true;
 }
 
@@ -1345,6 +1343,7 @@ void FullCodeGenerator::VisitForStatement(ForStatement* stmt) {
   SetStatementPosition(stmt);
 
   if (stmt->init() != NULL) {
+    SetStatementPosition(stmt->init());
     Visit(stmt->init());
   }
 
@@ -1359,6 +1358,7 @@ void FullCodeGenerator::VisitForStatement(ForStatement* stmt) {
   PrepareForBailoutForId(stmt->ContinueId(), NO_REGISTERS);
   __ bind(loop_statement.continue_label());
   if (stmt->next() != NULL) {
+    SetStatementPosition(stmt->next());
     Visit(stmt->next());
   }
 
@@ -1371,6 +1371,7 @@ void FullCodeGenerator::VisitForStatement(ForStatement* stmt) {
 
   __ bind(&test);
   if (stmt->cond() != NULL) {
+    SetExpressionPosition(stmt->cond());
     VisitForControl(stmt->cond(),
                     &body,
                     loop_statement.break_label(),
@@ -1385,6 +1386,47 @@ void FullCodeGenerator::VisitForStatement(ForStatement* stmt) {
 }
 
 
+void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
+  Comment cmnt(masm_, "[ ForOfStatement");
+  SetStatementPosition(stmt);
+
+  Iteration loop_statement(this, stmt);
+  increment_loop_depth();
+
+  // var iterator = iterable[Symbol.iterator]();
+  VisitForEffect(stmt->assign_iterator());
+
+  // Loop entry.
+  __ bind(loop_statement.continue_label());
+
+  // result = iterator.next()
+  SetExpressionPosition(stmt->next_result());
+  VisitForEffect(stmt->next_result());
+
+  // if (result.done) break;
+  Label result_not_done;
+  VisitForControl(stmt->result_done(), loop_statement.break_label(),
+                  &result_not_done, &result_not_done);
+  __ bind(&result_not_done);
+
+  // each = result.value
+  VisitForEffect(stmt->assign_each());
+
+  // Generate code for the body of the loop.
+  Visit(stmt->body());
+
+  // Check stack before looping.
+  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
+  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
+  __ jmp(loop_statement.continue_label());
+
+  // Exit and decrement the loop depth.
+  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
+  __ bind(loop_statement.break_label());
+  decrement_loop_depth();
+}
+
+
 void FullCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
   Comment cmnt(masm_, "[ TryCatchStatement");
   SetStatementPosition(stmt);

src/ia32/full-codegen-ia32.cc

@@ -1045,6 +1045,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
+  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ cmp(eax, isolate()->factory()->undefined_value());
   __ j(equal, &exit);
@@ -1139,6 +1140,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Generate code for doing the condition check.
   PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ bind(&loop);
+  SetExpressionPosition(stmt->each());
+
   __ mov(eax, Operand(esp, 0 * kPointerSize));  // Get the current index.
   __ cmp(eax, Operand(esp, 1 * kPointerSize));  // Compare to the array length.
   __ j(above_equal, loop_statement.break_label());
@@ -1205,48 +1208,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
-void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
-  Comment cmnt(masm_, "[ ForOfStatement");
-  SetStatementPosition(stmt);
-
-  Iteration loop_statement(this, stmt);
-  increment_loop_depth();
-
-  // var iterator = iterable[Symbol.iterator]();
-  VisitForEffect(stmt->assign_iterator());
-
-  // Loop entry.
-  __ bind(loop_statement.continue_label());
-
-  // result = iterator.next()
-  VisitForEffect(stmt->next_result());
-
-  // if (result.done) break;
-  Label result_not_done;
-  VisitForControl(stmt->result_done(),
-                  loop_statement.break_label(),
-                  &result_not_done,
-                  &result_not_done);
-  __ bind(&result_not_done);
-
-  // each = result.value
-  VisitForEffect(stmt->assign_each());
-
-  // Generate code for the body of the loop.
-  Visit(stmt->body());
-
-  // Check stack before looping.
-  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
-  __ jmp(loop_statement.continue_label());
-
-  // Exit and decrement the loop depth.
-  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_label());
-  decrement_loop_depth();
-}
-
-
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new

src/mips/full-codegen-mips.cc

@@ -1102,6 +1102,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
+  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ mov(a0, result_register());  // Result as param to InvokeBuiltin below.
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
@@ -1201,6 +1202,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Generate code for doing the condition check.
   PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ bind(&loop);
+  SetExpressionPosition(stmt->each());
+
   // Load the current count to a0, load the length to a1.
   __ lw(a0, MemOperand(sp, 0 * kPointerSize));
   __ lw(a1, MemOperand(sp, 1 * kPointerSize));
@@ -1270,48 +1273,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
-void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
-  Comment cmnt(masm_, "[ ForOfStatement");
-  SetStatementPosition(stmt);
-
-  Iteration loop_statement(this, stmt);
-  increment_loop_depth();
-
-  // var iterator = iterable[Symbol.iterator]();
-  VisitForEffect(stmt->assign_iterator());
-
-  // Loop entry.
-  __ bind(loop_statement.continue_label());
-
-  // result = iterator.next()
-  VisitForEffect(stmt->next_result());
-
-  // if (result.done) break;
-  Label result_not_done;
-  VisitForControl(stmt->result_done(),
-                  loop_statement.break_label(),
-                  &result_not_done,
-                  &result_not_done);
-  __ bind(&result_not_done);
-
-  // each = result.value
-  VisitForEffect(stmt->assign_each());
-
-  // Generate code for the body of the loop.
-  Visit(stmt->body());
-
-  // Check stack before looping.
-  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
-  __ jmp(loop_statement.continue_label());
-
-  // Exit and decrement the loop depth.
-  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_label());
-  decrement_loop_depth();
-}
-
-
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new

src/mips64/full-codegen-mips64.cc

@@ -1097,6 +1097,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
+  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ mov(a0, result_register());  // Result as param to InvokeBuiltin below.
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
@@ -1196,6 +1197,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Generate code for doing the condition check.
   PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ bind(&loop);
+  SetExpressionPosition(stmt->each());
+
   // Load the current count to a0, load the length to a1.
   __ ld(a0, MemOperand(sp, 0 * kPointerSize));
   __ ld(a1, MemOperand(sp, 1 * kPointerSize));
@@ -1265,48 +1268,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
-void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
-  Comment cmnt(masm_, "[ ForOfStatement");
-  SetStatementPosition(stmt);
-
-  Iteration loop_statement(this, stmt);
-  increment_loop_depth();
-
-  // var iterator = iterable[Symbol.iterator]();
-  VisitForEffect(stmt->assign_iterator());
-
-  // Loop entry.
-  __ bind(loop_statement.continue_label());
-
-  // result = iterator.next()
-  VisitForEffect(stmt->next_result());
-
-  // if (result.done) break;
-  Label result_not_done;
-  VisitForControl(stmt->result_done(),
-                  loop_statement.break_label(),
-                  &result_not_done,
-                  &result_not_done);
-  __ bind(&result_not_done);
-
-  // each = result.value
-  VisitForEffect(stmt->assign_each());
-
-  // Generate code for the body of the loop.
-  Visit(stmt->body());
-
-  // Check stack before looping.
-  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
-  __ jmp(loop_statement.continue_label());
-
-  // Exit and decrement the loop depth.
-  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_label());
-  decrement_loop_depth();
-}
-
-
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new

src/parser.cc

@@ -2941,7 +2941,7 @@ void Parser::InitializeForEachStatement(ForEachStatement* stmt,
     // var iterator = subject[Symbol.iterator]();
     assign_iterator = factory()->NewAssignment(
         Token::ASSIGN, factory()->NewVariableProxy(iterator),
-        GetIterator(subject, factory()), RelocInfo::kNoPosition);
+        GetIterator(subject, factory()), subject->position());
 
     // var result = iterator.next();
     {
@@ -2952,11 +2952,11 @@ void Parser::InitializeForEachStatement(ForEachStatement* stmt,
           iterator_proxy, next_literal, RelocInfo::kNoPosition);
       ZoneList<Expression*>* next_arguments =
           new(zone()) ZoneList<Expression*>(0, zone());
-      Expression* next_call = factory()->NewCall(
+      Expression* next_call = factory()->NewCall(next_property, next_arguments,
-          next_property, next_arguments, RelocInfo::kNoPosition);
+                                                 subject->position());
       Expression* result_proxy = factory()->NewVariableProxy(result);
-      next_result = factory()->NewAssignment(
+      next_result = factory()->NewAssignment(Token::ASSIGN, result_proxy,
-          Token::ASSIGN, result_proxy, next_call, RelocInfo::kNoPosition);
+                                             next_call, subject->position());
     }
 
     // result.done
@@ -2975,8 +2975,8 @@ void Parser::InitializeForEachStatement(ForEachStatement* stmt,
       Expression* result_proxy = factory()->NewVariableProxy(result);
       Expression* result_value = factory()->NewProperty(
           result_proxy, value_literal, RelocInfo::kNoPosition);
-      assign_each = factory()->NewAssignment(
+      assign_each = factory()->NewAssignment(Token::ASSIGN, each, result_value,
-          Token::ASSIGN, each, result_value, RelocInfo::kNoPosition);
+                                             each->position());
     }
 
     for_of->Initialize(each, subject, body,
@@ -3154,7 +3154,7 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
   // ForStatement ::
   //   'for' '(' Expression? ';' Expression? ';' Expression? ')' Statement
 
-  int pos = peek_position();
+  int stmt_pos = peek_position();
   Statement* init = NULL;
   ZoneList<const AstRawString*> let_bindings(1, zone());
 
@@ -3177,19 +3177,20 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
                                     CHECK_OK);
       bool accept_OF = decl_props == kHasNoInitializers;
       ForEachStatement::VisitMode mode;
+      int each_pos = position();
 
       if (name != NULL && CheckInOrOf(accept_OF, &mode)) {
         Interface* interface =
             is_const ? Interface::NewConst() : Interface::NewValue();
         ForEachStatement* loop =
-            factory()->NewForEachStatement(mode, labels, pos);
+            factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
         Expression* enumerable = ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
         VariableProxy* each =
-            scope_->NewUnresolved(factory(), name, interface);
+            scope_->NewUnresolved(factory(), name, interface, each_pos);
         Statement* body = ParseStatement(NULL, CHECK_OK);
         InitializeForEachStatement(loop, each, enumerable, body);
         Block* result =
@@ -3216,6 +3217,7 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
       bool accept_IN = name != NULL && decl_props != kHasInitializers;
       bool accept_OF = decl_props == kHasNoInitializers;
       ForEachStatement::VisitMode mode;
+      int each_pos = position();
 
       if (accept_IN && CheckInOrOf(accept_OF, &mode)) {
         // Rewrite a for-in statement of the form
@@ -3235,9 +3237,9 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
         // implementing stack allocated block scoped variables.
         Variable* temp = scope_->DeclarationScope()->NewTemporary(
             ast_value_factory()->dot_for_string());
-        VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
+        VariableProxy* temp_proxy = factory()->NewVariableProxy(temp, each_pos);
         ForEachStatement* loop =
-            factory()->NewForEachStatement(mode, labels, pos);
+            factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
         // The expression does not see the loop variable.
@@ -3246,7 +3248,8 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
         scope_ = for_scope;
         Expect(Token::RPAREN, CHECK_OK);
 
-        VariableProxy* each = scope_->NewUnresolved(factory(), name);
+        VariableProxy* each = scope_->NewUnresolved(
+            factory(), name, Interface::NewValue(), each_pos);
         Statement* body = ParseStatement(NULL, CHECK_OK);
         Block* body_block =
             factory()->NewBlock(NULL, 3, false, RelocInfo::kNoPosition);
@@ -3280,7 +3283,7 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
             expression, lhs_location, "invalid_lhs_in_for", CHECK_OK);
 
         ForEachStatement* loop =
-            factory()->NewForEachStatement(mode, labels, pos);
+            factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
         Expression* enumerable = ParseExpression(true, CHECK_OK);
@@ -3296,14 +3299,13 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
         return loop;
 
       } else {
-        init = factory()->NewExpressionStatement(
+        init = factory()->NewExpressionStatement(expression, position());
-            expression, RelocInfo::kNoPosition);
       }
     }
   }
 
   // Standard 'for' loop
-  ForStatement* loop = factory()->NewForStatement(labels, pos);
+  ForStatement* loop = factory()->NewForStatement(labels, stmt_pos);
   Target target(&this->target_stack_, loop);
 
   // Parsed initializer at this point.
@@ -3326,8 +3328,9 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
 
   Statement* next = NULL;
   if (peek() != Token::RPAREN) {
+    int next_pos = position();
     Expression* exp = ParseExpression(true, CHECK_OK);
-    next = factory()->NewExpressionStatement(exp, RelocInfo::kNoPosition);
+    next = factory()->NewExpressionStatement(exp, next_pos);
   }
   Expect(Token::RPAREN, CHECK_OK);
 

src/x64/full-codegen-x64.cc

@@ -1067,6 +1067,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
+  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
   __ j(equal, &exit);
@@ -1170,6 +1171,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Generate code for doing the condition check.
   PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ bind(&loop);
+  SetExpressionPosition(stmt->each());
+
   __ movp(rax, Operand(rsp, 0 * kPointerSize));  // Get the current index.
   __ cmpp(rax, Operand(rsp, 1 * kPointerSize));  // Compare to the array length.
   __ j(above_equal, loop_statement.break_label());
@@ -1239,48 +1242,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
-void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
-  Comment cmnt(masm_, "[ ForOfStatement");
-  SetStatementPosition(stmt);
-
-  Iteration loop_statement(this, stmt);
-  increment_loop_depth();
-
-  // var iterator = iterable[Symbol.iterator]();
-  VisitForEffect(stmt->assign_iterator());
-
-  // Loop entry.
-  __ bind(loop_statement.continue_label());
-
-  // result = iterator.next()
-  VisitForEffect(stmt->next_result());
-
-  // if (result.done) break;
-  Label result_not_done;
-  VisitForControl(stmt->result_done(),
-                  loop_statement.break_label(),
-                  &result_not_done,
-                  &result_not_done);
-  __ bind(&result_not_done);
-
-  // each = result.value
-  VisitForEffect(stmt->assign_each());
-
-  // Generate code for the body of the loop.
-  Visit(stmt->body());
-
-  // Check stack before looping.
-  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
-  __ jmp(loop_statement.continue_label());
-
-  // Exit and decrement the loop depth.
-  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_label());
-  decrement_loop_depth();
-}
-
-
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new

src/x87/full-codegen-x87.cc

@@ -1034,6 +1034,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
+  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ cmp(eax, isolate()->factory()->undefined_value());
   __ j(equal, &exit);
@@ -1128,6 +1129,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Generate code for doing the condition check.
   PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ bind(&loop);
+  SetExpressionPosition(stmt->each());
+
   __ mov(eax, Operand(esp, 0 * kPointerSize));  // Get the current index.
   __ cmp(eax, Operand(esp, 1 * kPointerSize));  // Compare to the array length.
   __ j(above_equal, loop_statement.break_label());
@@ -1194,48 +1197,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
-void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
-  Comment cmnt(masm_, "[ ForOfStatement");
-  SetStatementPosition(stmt);
-
-  Iteration loop_statement(this, stmt);
-  increment_loop_depth();
-
-  // var iterator = iterable[Symbol.iterator]();
-  VisitForEffect(stmt->assign_iterator());
-
-  // Loop entry.
-  __ bind(loop_statement.continue_label());
-
-  // result = iterator.next()
-  VisitForEffect(stmt->next_result());
-
-  // if (result.done) break;
-  Label result_not_done;
-  VisitForControl(stmt->result_done(),
-                  loop_statement.break_label(),
-                  &result_not_done,
-                  &result_not_done);
-  __ bind(&result_not_done);
-
-  // each = result.value
-  VisitForEffect(stmt->assign_each());
-
-  // Generate code for the body of the loop.
-  Visit(stmt->body());
-
-  // Check stack before looping.
-  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
-  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
-  __ jmp(loop_statement.continue_label());
-
-  // Exit and decrement the loop depth.
-  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_label());
-  decrement_loop_depth();
-}
-
-
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new

test/cctest/test-debug.cc

@@ -2860,7 +2860,7 @@ TEST(DebugStepKeyedLoadLoop) {
   foo->Call(env->Global(), kArgc, args);
 
   // With stepping all break locations are hit.
-  CHECK_EQ(35, break_point_hit_count);
+  CHECK_EQ(45, break_point_hit_count);
 
   v8::Debug::SetDebugEventListener(NULL);
   CheckDebuggerUnloaded();
@@ -2908,7 +2908,7 @@ TEST(DebugStepKeyedStoreLoop) {
   foo->Call(env->Global(), kArgc, args);
 
   // With stepping all break locations are hit.
-  CHECK_EQ(34, break_point_hit_count);
+  CHECK_EQ(44, break_point_hit_count);
 
   v8::Debug::SetDebugEventListener(NULL);
   CheckDebuggerUnloaded();
@@ -2952,7 +2952,7 @@ TEST(DebugStepNamedLoadLoop) {
   foo->Call(env->Global(), 0, NULL);
 
   // With stepping all break locations are hit.
-  CHECK_EQ(55, break_point_hit_count);
+  CHECK_EQ(65, break_point_hit_count);
 
   v8::Debug::SetDebugEventListener(NULL);
   CheckDebuggerUnloaded();
@@ -2995,9 +2995,7 @@ static void DoDebugStepNamedStoreLoop(int expected) {
 
 
 // Test of the stepping mechanism for named load in a loop.
-TEST(DebugStepNamedStoreLoop) {
+TEST(DebugStepNamedStoreLoop) { DoDebugStepNamedStoreLoop(34); }
-  DoDebugStepNamedStoreLoop(24);
-}
 
 
 // Test the stepping mechanism with different ICs.
@@ -3330,14 +3328,14 @@ TEST(DebugStepFor) {
   break_point_hit_count = 0;
   v8::Handle<v8::Value> argv_10[argc] = { v8::Number::New(isolate, 10) };
   foo->Call(env->Global(), argc, argv_10);
-  CHECK_EQ(23, break_point_hit_count);
+  CHECK_EQ(45, break_point_hit_count);
 
   // Looping 100 times.
   step_action = StepIn;
   break_point_hit_count = 0;
   v8::Handle<v8::Value> argv_100[argc] = { v8::Number::New(isolate, 100) };
   foo->Call(env->Global(), argc, argv_100);
-  CHECK_EQ(203, break_point_hit_count);
+  CHECK_EQ(405, break_point_hit_count);
 
   // Get rid of the debug event listener.
   v8::Debug::SetDebugEventListener(NULL);
@@ -3381,7 +3379,7 @@ TEST(DebugStepForContinue) {
   v8::Handle<v8::Value> argv_10[argc] = { v8::Number::New(isolate, 10) };
   result = foo->Call(env->Global(), argc, argv_10);
   CHECK_EQ(5, result->Int32Value());
-  CHECK_EQ(52, break_point_hit_count);
+  CHECK_EQ(62, break_point_hit_count);
 
   // Looping 100 times.
   step_action = StepIn;
@@ -3389,7 +3387,7 @@ TEST(DebugStepForContinue) {
   v8::Handle<v8::Value> argv_100[argc] = { v8::Number::New(isolate, 100) };
   result = foo->Call(env->Global(), argc, argv_100);
   CHECK_EQ(50, result->Int32Value());
-  CHECK_EQ(457, break_point_hit_count);
+  CHECK_EQ(557, break_point_hit_count);
 
   // Get rid of the debug event listener.
   v8::Debug::SetDebugEventListener(NULL);
@@ -3434,7 +3432,7 @@ TEST(DebugStepForBreak) {
   v8::Handle<v8::Value> argv_10[argc] = { v8::Number::New(isolate, 10) };
   result = foo->Call(env->Global(), argc, argv_10);
   CHECK_EQ(9, result->Int32Value());
-  CHECK_EQ(55, break_point_hit_count);
+  CHECK_EQ(64, break_point_hit_count);
 
   // Looping 100 times.
   step_action = StepIn;
@@ -3442,7 +3440,7 @@ TEST(DebugStepForBreak) {
   v8::Handle<v8::Value> argv_100[argc] = { v8::Number::New(isolate, 100) };
   result = foo->Call(env->Global(), argc, argv_100);
   CHECK_EQ(99, result->Int32Value());
-  CHECK_EQ(505, break_point_hit_count);
+  CHECK_EQ(604, break_point_hit_count);
 
   // Get rid of the debug event listener.
   v8::Debug::SetDebugEventListener(NULL);
@@ -3473,7 +3471,7 @@ TEST(DebugStepForIn) {
   step_action = StepIn;
   break_point_hit_count = 0;
   foo->Call(env->Global(), 0, NULL);
-  CHECK_EQ(6, break_point_hit_count);
+  CHECK_EQ(8, break_point_hit_count);
 
   // Create a function for testing stepping. Run it to allow it to get
   // optimized.
@@ -3490,7 +3488,7 @@ TEST(DebugStepForIn) {
   step_action = StepIn;
   break_point_hit_count = 0;
   foo->Call(env->Global(), 0, NULL);
-  CHECK_EQ(8, break_point_hit_count);
+  CHECK_EQ(10, break_point_hit_count);
 
   // Get rid of the debug event listener.
   v8::Debug::SetDebugEventListener(NULL);

test/mjsunit/debug-step.js

@@ -68,7 +68,7 @@ bp1 = Debug.setBreakPoint(f, 1);
 state = 0;
 result = -1;
 f();
-assertEquals(499, result);
+assertEquals(332, result);
 
 // Check that performing 1000 steps with a break point on the statement in the
 // for loop (line 2) will only make i 0 as a real break point breaks even when

test/mjsunit/es6/debug-stepnext-for.js

@@ -0,0 +1,116 @@
+// Copyright 2014 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 --harmony
+
+Debug = debug.Debug;
+var break_count = 0
+var exception = null;
+var log = []
+
+var s = 0;
+var a = [1, 2, 3];
+var i = 0;
+
+function f() {
+  "use strict";
+  debugger;                      // Break a
+  var j;                         // Break b
+
+  for (var i in null) {          // Break c
+    s += a[i];
+  }
+
+  for (j in null) {              // Break d
+    s += a[j];
+  }
+
+  for (var i in a) {             // Break e
+    s += a[i];                   // Break E
+  }
+
+  for (j in a) {                 // Break f
+    s += a[j];                   // Break F
+  }
+
+  for (let i in a) {             // Break g
+    s += a[i];                   // Break G
+  }
+
+  for (var i of a) {             // Break h
+    s += i;                      // Break H
+  }
+
+  for (j of a) {                 // Break i
+    s += j;                      // Break I
+  }
+
+  for (let i of a) {             // Break j
+    s += i;                      // Break J
+  }
+
+  for (var i = 0; i < 3; i++) {  // Break k
+    s += a[i];                   // Break K
+  }
+
+  for (j = 0; j < 3; j++) {      // Break l
+    s += a[j];                   // Break L
+  }
+
+  // TODO(yangguo): add test case for for-let.
+}                                // Break y
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    var line = exec_state.frame(0).sourceLineText();
+    var col = exec_state.frame(0).sourceColumn();
+    print(line);
+    var match = line.match(/\/\/ Break (\w)$/);
+    assertEquals(2, match.length);
+    log.push(match[1] + col);
+    exec_state.prepareStep(Debug.StepAction.StepNext, 1);
+    break_count++;
+  } catch (e) {
+    exception = e;
+  }
+}
+
+Debug.setListener(listener);
+f();
+Debug.setListener(null);         // Break z
+
+print(JSON.stringify(log));
+// The let declaration differs from var in that the loop variable
+// is declared in every iteration.
+var expected = [
+  // Entry
+  "a2","b2",
+  // Empty for-in-var: var decl, get enumerable
+  "c7","c16",
+  // Empty for-in: get enumerable
+  "d12",
+  // For-in-var: var decl, get enumerable, assign, body, assign, body, ...
+  "e7","e16","e11","E4","e11","E4","e11","E4","e11",
+  // For-in: get enumerable, assign, body, assign, body, ...
+  "f12","f7","F4","f7","F4","f7","F4","f7",
+  // For-in-let: get enumerable, next, new let, body, next, new let, ...
+  "g16","g11","g7","G4","g11","g7","G4","g11","g7","G4","g11",
+  // For-of-var: var decl, next(), body, next(), body, ...
+  "h7","h16","H4","h16","H4","h16","H4","h16",
+  // For-of: next(), body, next(), body, ...
+  "i12","I4","i12","I4","i12","I4","i12",
+  // For-of-let: next(), new let, body, next(), new let, ...
+  "j16","j7","J4","j16","j7","J4","j16","j7","J4","j16",
+  // For-var: var decl, condition, body, next, condition, body, ...
+  "k7","k20","K4","k23","k20","K4","k23","k20","K4","k23","k20",
+  // For: init, condition, body, next, condition, body, ...
+  "l11","l16","L4","l19","l16","L4","l19","l16","L4","l19","l16",
+  // Exit.
+  "y0","z0",
+]
+
+assertArrayEquals(expected, log);
+assertEquals(48, s);
+assertNull(exception);