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

src/arm/assembler-arm-inl.h

Index: src/arm/assembler-arm-inl.h
diff --git a/src/arm/assembler-arm-inl.h b/src/arm/assembler-arm-inl.h
index dfb00305fd378eea802482df1296ac08e33731a3..ae7346b7d7d75c843d7713da721b66cd40d819f1 100644
--- a/src/arm/assembler-arm-inl.h
+++ b/src/arm/assembler-arm-inl.h
@@ -76,6 +76,11 @@ Address RelocInfo::wasm_memory_reference() {
   return Assembler::target_address_at(pc_, host_);
 }
 
+uint32_t RelocInfo::wasm_memory_size_reference() {
+  DCHECK(IsWasmMemorySizeReference(rmode_));
+  return reinterpret_cast<uint32_t>(Assembler::target_address_at(pc_, host_));
+}
+
 Address RelocInfo::target_address_address() {
   DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_)
                               || rmode_ == EMBEDDED_OBJECT
@@ -119,16 +124,30 @@ void RelocInfo::set_target_address(Address target,
 }
 
 void RelocInfo::update_wasm_memory_reference(

[titzer, 2016/05/04 11:21:22]

Can we move this into the .cc file? There are other big methods here, but I
think this isn't performance critical enough to warrant being in the -inl.h
file.

Here and in the other architectures as well.

[gdeepti, 2016/05/04 20:14:52]

Done.

-    Address old_base, Address new_base, size_t old_size, size_t new_size,
+    Address old_base, Address new_base, uint32_t old_size, uint32_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_)) {
+    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_)) {
+    uint32_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);
+    Assembler::set_target_address_at(
+        isolate_, pc_, host_, reinterpret_cast<Address>(updated_size_reference),
+        icache_flush_mode);
+  } else {
+    UNREACHABLE();
+  }
 }
 
 Object* RelocInfo::target_object() {