[wasm] add atomic opcodes

src/wasm/wasm-opcodes.cc

Index: src/wasm/wasm-opcodes.cc
diff --git a/src/wasm/wasm-opcodes.cc b/src/wasm/wasm-opcodes.cc
index cd2dde47480c9a6323006e361d3bb6af89990b6b..8f81b81a50bd9c4eb54c8952a354c227532a644d 100644
--- a/src/wasm/wasm-opcodes.cc
+++ b/src/wasm/wasm-opcodes.cc
@@ -88,6 +88,7 @@ static const FunctionSig* kSimdExprSigs[] = {
 static byte kSimpleExprSigTable[256];
 static byte kSimpleAsmjsExprSigTable[256];
 static byte kSimdExprSigTable[256];
+static byte kAtomicExprSigTable[256];
 
 // Initialize the signature table.
 static void InitSigTables() {
@@ -105,6 +106,12 @@ static void InitSigTables() {
   kSimdExprSigTable[simd_index] = static_cast<int>(kSigEnum_##sig) + 1;
   FOREACH_SIMD_0_OPERAND_OPCODE(SET_SIG_TABLE)
 #undef SET_SIG_TABLE
+  byte atomic_index;
+#define SET_ATOMIC_SIG_TABLE(name, opcode, sig) \
+  atomic_index = opcode & 0xff;                 \
+  kAtomicExprSigTable[atomic_index] = static_cast<int>(kSigEnum_##sig) + 1;
+  FOREACH_ATOMIC_OPCODE(SET_ATOMIC_SIG_TABLE)
+#undef SET_ATOMIC_SIG_TABLE
 }
 
 class SigTable {
@@ -125,6 +132,10 @@ class SigTable {
     return const_cast<FunctionSig*>(
         kSimdExprSigs[kSimdExprSigTable[static_cast<byte>(opcode & 0xff)]]);
   }
+  FunctionSig* AtomicSignature(WasmOpcode opcode) const {
+    return const_cast<FunctionSig*>(
+        kSimpleExprSigs[kAtomicExprSigTable[static_cast<byte>(opcode & 0xff)]]);
+  }
 };
 
 static base::LazyInstance<SigTable>::type sig_table = LAZY_INSTANCE_INITIALIZER;
@@ -141,6 +152,10 @@ FunctionSig* WasmOpcodes::AsmjsSignature(WasmOpcode opcode) {
   return sig_table.Get().AsmjsSignature(opcode);
 }
 
+FunctionSig* WasmOpcodes::AtomicSignature(WasmOpcode opcode) {
+  return sig_table.Get().AtomicSignature(opcode);
+}
+
 // TODO(titzer): pull WASM_64 up to a common header.
 #if !V8_TARGET_ARCH_32_BIT || V8_TARGET_ARCH_X64
 #define WASM_64 1