Convert SIMD wasm ops to runtime function calls

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 afb1eff36687a622a4bb62b3a118281d0af8c10a..535b0aafbbdd6100257c825f277fa29663a57873 100644
--- a/src/wasm/wasm-opcodes.cc
+++ b/src/wasm/wasm-opcodes.cc
@@ -68,7 +68,13 @@ FOREACH_SIGNATURE(DECLARE_SIG)
 static const FunctionSig* kSimpleExprSigs[] = {
     nullptr, FOREACH_SIGNATURE(DECLARE_SIG_ENTRY)};
 
+#define DECLARE_SIMD_SIG_ENTRY(name, ...) &kSig_##name,
+
+static const FunctionSig* kSimdExprSigs[] = {
+    nullptr, FOREACH_SIMD_SIGNATURE(DECLARE_SIMD_SIG_ENTRY)};
+
 static byte kSimpleExprSigTable[256];
+static byte kSimdExprSigTable[256];
 
 // Initialize the signature table.
 static void InitSigTable() {
@@ -80,22 +86,41 @@ static void InitSigTable() {
 #undef SET_SIG_TABLE
 }
 
+// Initialize the signature table.

[titzer, 2016/07/08 14:16:03]

You can just merge this with the above function and rename it to
InitSigTables().

[gdeepti, 2016/07/11 09:50:34]

Done.

+static void InitSimdSigTable() {
+  byte simd_index;
+#define SET_SIG_TABLE(name, opcode, sig) \
+  simd_index = opcode & 0xff;            \
+  kSimdExprSigTable[simd_index] = static_cast<int>(kSigEnum_##sig) + 1;
+  FOREACH_SIMD_OPCODE(SET_SIG_TABLE)
+#undef SET_SIG_TABLE
+}
+
 class SigTable {
  public:
   SigTable() {
     // TODO(ahaas): Move {InitSigTable} into the class.
     InitSigTable();
+    InitSimdSigTable();
   }
   FunctionSig* Signature(WasmOpcode opcode) const {
     return const_cast<FunctionSig*>(
         kSimpleExprSigs[kSimpleExprSigTable[static_cast<byte>(opcode)]]);
   }
+  FunctionSig* SimdSignature(WasmOpcode opcode) const {
+    return const_cast<FunctionSig*>(
+        kSimdExprSigs[kSimdExprSigTable[static_cast<byte>(opcode & 0xff)]]);
+  }
 };
 
 static base::LazyInstance<SigTable>::type sig_table = LAZY_INSTANCE_INITIALIZER;
 
 FunctionSig* WasmOpcodes::Signature(WasmOpcode opcode) {
-  return sig_table.Get().Signature(opcode);
+  if (opcode >> 8 == kSimdPrefix) {
+    return sig_table.Get().SimdSignature(opcode);
+  } else {
+    return sig_table.Get().Signature(opcode);
+  }
 }
 
 // TODO(titzer): pull WASM_64 up to a common header.