Assembler changes for enabling GrowHeap in Wasm

src/arm64/assembler-arm64-inl.h

Index: src/arm64/assembler-arm64-inl.h
diff --git a/src/arm64/assembler-arm64-inl.h b/src/arm64/assembler-arm64-inl.h
index aeca563c37f577b5a2582ea3605c026d6ca23704..2aaaa726c1c0f3f1f2eabc817f4df8bf69d7c672 100644
--- a/src/arm64/assembler-arm64-inl.h
+++ b/src/arm64/assembler-arm64-inl.h
@@ -41,6 +41,17 @@ void RelocInfo::set_target_address(Address target,
   }
 }
 
+void RelocInfo::update_wasm_memory_reference(
+    Address old_base, Address new_base, size_t old_size, size_t new_size,
+    ICacheFlushMode icache_flush_mode) {
+  DCHECK(IsWasmMemoryReference(rmode_));
+  DCHECK(new_size > old_size);
+  DCHECK(old_base + old_size >= wasm_memory_reference());
+  Address updated_reference = wasm_memory_reference() + (new_base - old_base);
+  DCHECK(new_base + new_size >= updated_reference);
+  Assembler::set_target_address_at(isolate_, pc_, host_, updated_reference,

[Yang, 2016/03/08 05:41:50]

There doesn't seem to be anything platform dependent here. Would it be possible
to move this to src/assembler.cc?

[gdeepti1, 2016/03/09 04:01:43]

Added it in platform specific headers because that seemed to be the case for all
other INLINE functions defined in assembler.h. Would you prefer that it was
changed to a regular function and moved to assembler.cc? 

[gdeepti1, 2016/03/11 03:55:51]

Update from previous comment - the bounds checking in this function was
incorrect for ia32/x64 because target_address_at/set_target_address_at methods
use pc relative addresses. Fixed in the latest patch, this does make the
implementation slightly different for ia32/x64 vs arm/arm64. 

+                                   icache_flush_mode);
+}
 
 inline int CPURegister::code() const {
   DCHECK(IsValid());
@@ -693,6 +704,10 @@ Address RelocInfo::target_address() {
   return Assembler::target_address_at(pc_, host_);
 }
 
+Address RelocInfo::wasm_memory_reference() {
+  DCHECK(IsWasmMemoryReference(rmode_));
+  return Assembler::target_address_at(pc_, host_);
+}
 
 Address RelocInfo::target_address_address() {
   DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_)