Add new relocation type WASM_MEMORY_SIZE_REFERENCE, use relocatable pointers to update wasm memory …

src/compiler/arm64/code-generator-arm64.cc

 // 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.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/arm64/frames-arm64.h"
 #include "src/arm64/macro-assembler-arm64.h"
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
@@ skipping 165 matching lines @@
     if (op->IsRegister()) {
       return Operand(ToRegister(op).W());
     }
     return ToImmediate(op);
   }
 
   Operand ToImmediate(InstructionOperand* operand) {
     Constant constant = ToConstant(operand);
     switch (constant.type()) {
       case Constant::kInt32:
-        return Operand(constant.ToInt32());
+        if (constant.rmode() == RelocInfo::WASM_MEMORY_SIZE_REFERENCE) {
+          return Operand(constant.ToInt32(), constant.rmode());
+        } else {
+          return Operand(constant.ToInt32());
+        }
       case Constant::kInt64:
-        if (constant.rmode() == RelocInfo::WASM_MEMORY_REFERENCE) {
+        if (constant.rmode() == RelocInfo::WASM_MEMORY_REFERENCE ||
+            constant.rmode() == RelocInfo::WASM_MEMORY_SIZE_REFERENCE) {

[titzer, 2016/04/28 11:40:19]

I think we are limiting ourselves to 32 bit sizes now, so we can drop this case
(or even better, have a DCHECK). Here and in the other 64-bit code generators.

[gdeepti, 2016/05/02 23:56:08]

Dropped, and added a DCHECK for x64 & Arm64. There was a bug in the constructor
for RelocatablePtrConstantInfo which was causing relocatable int32 constants to
be treated as int64 constants. This was happening only on arm64 because x64 uses
the Immediates vector in compiler/instruction.h for adding/retrieving immediates
and does not use the constructor. Fixed now. 

           return Operand(constant.ToInt64(), constant.rmode());
         } else {
           return Operand(constant.ToInt64());
         }
       case Constant::kFloat32:
         return Operand(
             isolate()->factory()->NewNumber(constant.ToFloat32(), TENURED));
       case Constant::kFloat64:
         return Operand(
             isolate()->factory()->NewNumber(constant.ToFloat64(), TENURED));
@@ skipping 1656 matching lines @@
       padding_size -= kInstructionSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8