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

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

Index: src/compiler/arm64/code-generator-arm64.cc
diff --git a/src/compiler/arm64/code-generator-arm64.cc b/src/compiler/arm64/code-generator-arm64.cc
index 48c82f00d64eb3f17576994e8fbe81ac19c66255..e7062bdb7f921623709f25e47822c346a7986668 100644
--- a/src/compiler/arm64/code-generator-arm64.cc
+++ b/src/compiler/arm64/code-generator-arm64.cc
@@ -183,9 +183,14 @@ class Arm64OperandConverter final : public InstructionOperandConverter {
     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());