Switch CallConstructStub to take new.target in register.

src/arm/code-stubs-arm.cc

 // Copyright 2012 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/v8.h"
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 2589 matching lines @@
 
 void CallFunctionStub::Generate(MacroAssembler* masm) {
   CallFunctionNoFeedback(masm, argc(), NeedsChecks(), CallAsMethod());
 }
 
 
 void CallConstructStub::Generate(MacroAssembler* masm) {
   // r0 : number of arguments
   // r1 : the function to call
   // r2 : feedback vector
-  // r3 : (only if r2 is not the megamorphic symbol) slot in feedback
-  //      vector (Smi)
+  // r3 : slot in feedback vector (Smi, for RecordCallTarget)
+  // r4 : original constructor (for IsSuperConstructorCall)
   Label slow, non_function_call;
 
   // Check that the function is not a smi.
   __ JumpIfSmi(r1, &non_function_call);
   // Check that the function is a JSFunction.
-  __ CompareObjectType(r1, r4, r4, JS_FUNCTION_TYPE);
+  __ CompareObjectType(r1, r5, r5, JS_FUNCTION_TYPE);
   __ b(ne, &slow);
 
   if (RecordCallTarget()) {
+    if (IsSuperConstructorCall()) {
+      __ push(r4);

[Michael Starzinger, 2015/07/14 15:02:47]

Potentially applies to all architectures: Note that I realize that on some
architectures we could probably avoid this push and the pop a few lines below,
by massaging GenerateRecordCallTarget appropriately so that it preserves the
register in question. However I would like to do this in a follow-up CL if
possible. But I am of course happy to leave a TODO for all architectures where
this might apply, just let me know.

[jbramley, 2015/07/14 16:57:35]

A TODO is probably a good idea, but it's up to you. On ARM64,
GenerateRecordCallTarget takes a list of scratch registers, and that approach
works quite well.

[Michael Starzinger, 2015/07/15 07:36:36]

Done. Added a TODO here.

+    }
     GenerateRecordCallTarget(masm);
+    if (IsSuperConstructorCall()) {
+      __ pop(r4);
+    }
 
     __ add(r5, r2, Operand::PointerOffsetFromSmiKey(r3));
     if (FLAG_pretenuring_call_new) {
       // Put the AllocationSite from the feedback vector into r2.
       // By adding kPointerSize we encode that we know the AllocationSite
       // entry is at the feedback vector slot given by r3 + 1.
       __ ldr(r2, FieldMemOperand(r5, FixedArray::kHeaderSize + kPointerSize));
     } else {
       Label feedback_register_initialized;
       // Put the AllocationSite from the feedback vector into r2, or undefined.
       __ ldr(r2, FieldMemOperand(r5, FixedArray::kHeaderSize));
       __ ldr(r5, FieldMemOperand(r2, AllocationSite::kMapOffset));
       __ CompareRoot(r5, Heap::kAllocationSiteMapRootIndex);
       __ b(eq, &feedback_register_initialized);
       __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
       __ bind(&feedback_register_initialized);
     }
 
     __ AssertUndefinedOrAllocationSite(r2, r5);
   }
 
   // Pass function as original constructor.
   if (IsSuperConstructorCall()) {
-    __ mov(r4, Operand(1 * kPointerSize));
-    __ add(r4, r4, Operand(r0, LSL, kPointerSizeLog2));
-    __ ldr(r3, MemOperand(sp, r4));
+    __ mov(r3, r4);
   } else {
     __ mov(r3, r1);
   }
 
   // Jump to the function-specific construct stub.
   Register jmp_reg = r4;
   __ ldr(jmp_reg, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
   __ ldr(jmp_reg, FieldMemOperand(jmp_reg,
                                   SharedFunctionInfo::kConstructStubOffset));
   __ add(pc, jmp_reg, Operand(Code::kHeaderSize - kHeapObjectTag));
 
   // r0: number of arguments
   // r1: called object
-  // r4: object type
+  // r5: object type
   Label do_call;
   __ bind(&slow);
-  __ cmp(r4, Operand(JS_FUNCTION_PROXY_TYPE));
+  __ cmp(r5, Operand(JS_FUNCTION_PROXY_TYPE));
   __ b(ne, &non_function_call);
   __ GetBuiltinFunction(r1, Builtins::CALL_FUNCTION_PROXY_AS_CONSTRUCTOR);
   __ jmp(&do_call);
 
   __ bind(&non_function_call);
   __ GetBuiltinFunction(r1, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
   __ bind(&do_call);
   // Set expected number of arguments to zero (not changing r0).
   __ mov(r2, Operand::Zero());
   __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
@@ skipping 2691 matching lines @@
                            MemOperand(fp, 6 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM