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

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 24 matching lines @@
                                    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,
+    Address old_base, Address new_base, int32_t old_size, int32_t new_size,
     ICacheFlushMode icache_flush_mode) {
-  DCHECK(IsWasmMemoryReference(rmode_));
-  DCHECK(old_base <= wasm_memory_reference() &&
-         wasm_memory_reference() < old_base + old_size);
-  Address updated_reference = new_base + (wasm_memory_reference() - old_base);
-  DCHECK(new_base <= updated_reference &&
-         updated_reference < new_base + new_size);
-  Assembler::set_target_address_at(isolate_, pc_, host_, updated_reference,
-                                   icache_flush_mode);
+  DCHECK(IsWasmMemoryReference(rmode_) || IsWasmMemorySizeReference(rmode_));
+  if (IsWasmMemoryReference(rmode_) && old_base != new_base) {
+    Address updated_memory_reference;
+    DCHECK(old_base <= wasm_memory_reference() &&
+           wasm_memory_reference() < old_base + old_size);
+    updated_memory_reference = new_base + (wasm_memory_reference() - old_base);
+    DCHECK(new_base <= updated_memory_reference &&
+           updated_memory_reference < new_base + new_size);
+    Assembler::set_target_address_at(
+        isolate_, pc_, host_, updated_memory_reference, icache_flush_mode);
+  } else if (IsWasmMemorySizeReference(rmode_)) {
+    int32_t updated_size_reference;
+    DCHECK(wasm_memory_size_reference() <= old_size);
+    updated_size_reference =
+        new_size + (wasm_memory_size_reference() - old_size);
+    DCHECK(updated_size_reference <= new_size);
+    Memory::int32_at(Assembler::target_pointer_address_at(pc_)) =
+        updated_size_reference;
+  } else {
+    UNREACHABLE();
+  }
 }
 
 inline int CPURegister::code() const {
   DCHECK(IsValid());
   return reg_code;
 }
 
 
 inline CPURegister::RegisterType CPURegister::type() const {
   DCHECK(IsValidOrNone());
@@ skipping 635 matching lines @@
 }
 
 
 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_);
+  return Memory::Address_at(Assembler::target_pointer_address_at(pc_));
+}
+
+int32_t RelocInfo::wasm_memory_size_reference() {
+  DCHECK(IsWasmMemorySizeReference(rmode_));
+  return Memory::int32_at(Assembler::target_pointer_address_at(pc_));
 }
 
 Address RelocInfo::target_address_address() {
   DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_)
                               || rmode_ == EMBEDDED_OBJECT
                               || rmode_ == EXTERNAL_REFERENCE);
   return Assembler::target_pointer_address_at(pc_);
 }
 
 
@@ skipping 533 matching lines @@
 
 void Assembler::ClearRecordedAstId() {
   recorded_ast_id_ = TypeFeedbackId::None();
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ARM64_ASSEMBLER_ARM64_INL_H_