Unify the stack layout for construct frames

src/arm/builtins-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/codegen.h"
 #include "src/debug.h"
@@ skipping 606 matching lines @@
       // r2 is an AllocationSite. We are creating a memento from it, so we
       // need to increment the memento create count.
       __ ldr(r3, FieldMemOperand(r2,
                                  AllocationSite::kPretenureCreateCountOffset));
       __ add(r3, r3, Operand(Smi::FromInt(1)));
       __ str(r3, FieldMemOperand(r2,
                                  AllocationSite::kPretenureCreateCountOffset));
       __ bind(&count_incremented);
     }
 
+    __ pop(r1);  // Constructor function.

[Dmitry Lomov (no reviews), 2015/06/24 15:49:47]

Use __ Drop(1)

[arv (Not doing code reviews), 2015/06/24 15:54:10]

That is not an option here because we need to have the constructor function in
r1. It is used on line 672

[Dmitry Lomov (no reviews), 2015/06/24 15:58:32]

Ah silly me. Thanks

+
     __ push(r4);
     __ push(r4);
 
-    // Reload the number of arguments and the constructor from the stack.
+    // Reload the number of arguments from the stack.
     // sp[0]: receiver
     // sp[1]: receiver
-    // sp[2]: constructor function
-    // sp[3]: number of arguments (smi-tagged)
-    __ ldr(r1, MemOperand(sp, 2 * kPointerSize));
-    __ ldr(r3, MemOperand(sp, 3 * kPointerSize));
+    // sp[2]: number of arguments (smi-tagged)
+    __ ldr(r3, MemOperand(sp, 2 * kPointerSize));
 
     // Set up pointer to last argument.
     __ add(r2, fp, Operand(StandardFrameConstants::kCallerSPOffset));
 
     // Set up number of arguments for function call below
     __ SmiUntag(r0, r3);
 
     // Copy arguments and receiver to the expression stack.
     // r0: number of arguments
     // r1: constructor function
@@ skipping 57 matching lines @@
     // Throw away the result of the constructor invocation and use the
     // on-stack receiver as the result.
     __ bind(&use_receiver);
     __ ldr(r0, MemOperand(sp));
 
     // Remove receiver from the stack, remove caller arguments, and
     // return.
     __ bind(&exit);
     // r0: result
     // sp[0]: receiver (newly allocated object)
-    // sp[1]: constructor function
-    // sp[2]: number of arguments (smi-tagged)
-    __ ldr(r1, MemOperand(sp, 2 * kPointerSize));
+    // sp[1]: number of arguments (smi-tagged)
+    __ ldr(r1, MemOperand(sp, kPointerSize));
 
     // Leave construct frame.
   }
 
   __ add(sp, sp, Operand(r1, LSL, kPointerSizeLog2 - 1));
   __ add(sp, sp, Operand(kPointerSize));
   __ IncrementCounter(isolate->counters()->constructed_objects(), 1, r1, r2);
   __ Jump(lr);
 }
 
@@ skipping 1083 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM