Implement optional turbofan UnalignedLoad and UnalignedStore operators

src/compiler/wasm-compiler.h

 // Copyright 2015 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_COMPILER_WASM_COMPILER_H_
 #define V8_COMPILER_WASM_COMPILER_H_
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/wasm/wasm-opcodes.h"
@@ skipping 101 matching lines @@
   Node* Invert(Node* node);
   Node* FunctionTable();
 
   //-----------------------------------------------------------------------
   // Operations that concern the linear memory.
   //-----------------------------------------------------------------------
   Node* MemSize(uint32_t offset);
   Node* LoadGlobal(uint32_t index);
   Node* StoreGlobal(uint32_t index, Node* val);
   Node* LoadMem(wasm::LocalType type, MachineType memtype, Node* index,
-                uint32_t offset);
-  Node* StoreMem(MachineType type, Node* index, uint32_t offset, Node* val);
+                uint32_t offset, bool aligned);

[titzer, 2016/03/22 15:00:20]

This alignment parameter will be more than a boolean. It's actually a power two,
under the theory that we can generate better code for a word32 load aligned on a
2-byte boundary.

+  Node* StoreMem(MachineType type, Node* index, uint32_t offset, bool aligned,
+                 Node* val);
 
   static void PrintDebugName(Node* node);
 
   Node* Control() { return *control_; }
   Node* Effect() { return *effect_; }
 
   void set_module(wasm::ModuleEnv* module) { this->module_ = module; }
 
   void set_control_ptr(Node** control) { this->control_ = control; }
 
@@ skipping 102 matching lines @@
     Node** buf = Buffer(count);
     if (buf != buffer) memcpy(buf, buffer, count * sizeof(Node*));
     return buf;
   }
 };
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_WASM_COMPILER_H_