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

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 86f8ce123f6784cf56671011e05885fc4c9dd77e..8a0aa13176be07e09c78096337003c0aa26a53a0 100644
--- a/src/arm64/assembler-arm64-inl.h
+++ b/src/arm64/assembler-arm64-inl.h
@@ -42,16 +42,29 @@ 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,
+    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 {
@@ -707,7 +720,12 @@ Address RelocInfo::target_address() {
 
 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() {