Support fast case for-in in Crankshaft.

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 857622d5459d2f9351f716c63770c35da2f23e1a..bacea586df588b95fa88224e7ba63d36bca39438 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -925,6 +925,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ cmp(eax, isolate()->factory()->null_value());
   __ j(equal, &exit);
 
+  PrepareForBailoutForId(stmt->PrepareId(), TOS_REG);
+
   // Convert the object to a JS object.
   Label convert, done_convert;
   __ JumpIfSmi(eax, &convert, Label::kNear);
@@ -937,7 +939,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ push(eax);
 
   // Check for proxies.
-  Label call_runtime;
+  Label call_runtime, use_cache, fixed_array;
   STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);
   __ CmpObjectType(eax, LAST_JS_PROXY_TYPE, ecx);
   __ j(below_equal, &call_runtime);
@@ -946,61 +948,19 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // the JSObject::IsSimpleEnum cache validity checks. If we cannot
   // guarantee cache validity, call the runtime system to check cache
   // validity or get the property names in a fixed array.
-  Label next;
-  __ mov(ecx, eax);
-  __ bind(&next);
-
-  // Check that there are no elements.  Register ecx contains the
-  // current JS object we've reached through the prototype chain.
-  __ cmp(FieldOperand(ecx, JSObject::kElementsOffset),
-         isolate()->factory()->empty_fixed_array());
-  __ j(not_equal, &call_runtime);
-
-  // Check that instance descriptors are not empty so that we can
-  // check for an enum cache.  Leave the map in ebx for the subsequent
-  // prototype load.
-  __ mov(ebx, FieldOperand(ecx, HeapObject::kMapOffset));
-  __ mov(edx, FieldOperand(ebx, Map::kInstanceDescriptorsOrBitField3Offset));
-  __ JumpIfSmi(edx, &call_runtime);
-
-  // Check that there is an enum cache in the non-empty instance
-  // descriptors (edx).  This is the case if the next enumeration
-  // index field does not contain a smi.
-  __ mov(edx, FieldOperand(edx, DescriptorArray::kEnumerationIndexOffset));
-  __ JumpIfSmi(edx, &call_runtime);
-
-  // For all objects but the receiver, check that the cache is empty.
-  Label check_prototype;
-  __ cmp(ecx, eax);
-  __ j(equal, &check_prototype, Label::kNear);
-  __ mov(edx, FieldOperand(edx, DescriptorArray::kEnumCacheBridgeCacheOffset));
-  __ cmp(edx, isolate()->factory()->empty_fixed_array());
-  __ j(not_equal, &call_runtime);
-
-  // Load the prototype from the map and loop if non-null.
-  __ bind(&check_prototype);
-  __ mov(ecx, FieldOperand(ebx, Map::kPrototypeOffset));
-  __ cmp(ecx, isolate()->factory()->null_value());
-  __ j(not_equal, &next);
+  __ CheckEnumCache(&call_runtime);
 
-  // The enum cache is valid.  Load the map of the object being
-  // iterated over and use the cache for the iteration.
-  Label use_cache;
   __ mov(eax, FieldOperand(eax, HeapObject::kMapOffset));
   __ jmp(&use_cache, Label::kNear);
 
   // Get the set of properties to enumerate.
   __ bind(&call_runtime);
-  __ push(eax);  // Duplicate the enumerable object on the stack.
+  __ push(eax);
   __ CallRuntime(Runtime::kGetPropertyNamesFast, 1);
-
-  // If we got a map from the runtime call, we can do a fast
-  // modification check. Otherwise, we got a fixed array, and we have
-  // to do a slow check.
-  Label fixed_array;
   __ cmp(FieldOperand(eax, HeapObject::kMapOffset),
          isolate()->factory()->meta_map());
-  __ j(not_equal, &fixed_array, Label::kNear);
+  __ j(not_equal, &fixed_array);
+
 
   // We got a map in register eax. Get the enumeration cache from it.
   __ bind(&use_cache);
@@ -1033,6 +993,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ push(Immediate(Smi::FromInt(0)));  // Initial index.
 
   // Generate code for doing the condition check.
+  PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
   __ bind(&loop);
   __ mov(eax, Operand(esp, 0 * kPointerSize));  // Get the current index.
   __ cmp(eax, Operand(esp, 1 * kPointerSize));  // Compare to the array length.
@@ -1075,7 +1036,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ mov(result_register(), ebx);
   // Perform the assignment as if via '='.
   { EffectContext context(this);
-    EmitAssignment(stmt->each(), stmt->AssignmentId());
+    EmitAssignment(stmt->each());
   }
 
   // Generate code for the body of the loop.
@@ -1094,6 +1055,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ add(esp, Immediate(5 * kPointerSize));
 
   // Exit and decrement the loop depth.
+  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
   __ bind(&exit);
   decrement_loop_depth();
 }
@@ -1853,7 +1815,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr,
 }
 
 
-void FullCodeGenerator::EmitAssignment(Expression* expr, int bailout_ast_id) {
+void FullCodeGenerator::EmitAssignment(Expression* expr) {
   // Invalid left-hand sides are rewritten to have a 'throw
   // ReferenceError' on the left-hand side.
   if (!expr->IsValidLeftHandSide()) {
@@ -1905,7 +1867,6 @@ void FullCodeGenerator::EmitAssignment(Expression* expr, int bailout_ast_id) {
       break;
     }
   }
-  PrepareForBailoutForId(bailout_ast_id, TOS_REG);
   context()->Plug(eax);
 }