Assembler changes for enabling GrowHeap in Wasm

src/arm64/assembler-arm64-inl.h

 // Copyright 2013 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.
 
 #ifndef V8_ARM64_ASSEMBLER_ARM64_INL_H_
 #define V8_ARM64_ASSEMBLER_ARM64_INL_H_
 
 #include "src/arm64/assembler-arm64.h"
 #include "src/assembler.h"
 #include "src/debug/debug.h"
@@ skipping 23 matching lines @@
   Assembler::set_target_address_at(isolate_, pc_, host_, target,
                                    icache_flush_mode);
   if (write_barrier_mode == UPDATE_WRITE_BARRIER && host() != NULL &&
       IsCodeTarget(rmode_)) {
     Object* target_code = Code::GetCodeFromTargetAddress(target);
     host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(
         host(), this, HeapObject::cast(target_code));
   }
 }
 
+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());
   return reg_code;
 }
 
 
 inline CPURegister::RegisterType CPURegister::type() const {
   DCHECK(IsValidOrNone());
   return reg_type;
@@ skipping 632 matching lines @@
 int RelocInfo::target_address_size() {
   return kPointerSize;
 }
 
 
 Address RelocInfo::target_address() {
   DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_));
   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_)
                               || rmode_ == EMBEDDED_OBJECT
                               || rmode_ == EXTERNAL_REFERENCE);
   return Assembler::target_pointer_address_at(pc_);
 }
 
 
 Address RelocInfo::constant_pool_entry_address() {
@@ skipping 532 matching lines @@
 
 void Assembler::ClearRecordedAstId() {
   recorded_ast_id_ = TypeFeedbackId::None();
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ARM64_ASSEMBLER_ARM64_INL_H_