Convert SIMD wasm ops to runtime function calls

src/wasm/ast-decoder.cc

 // 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.
 
 #include "src/signature.h"
 
 #include "src/bit-vector.h"
 #include "src/flags.h"
 #include "src/handles.h"
 #include "src/zone-containers.h"
@@ skipping 504 matching lines @@
   TFNode* DefaultValue(LocalType type) {
     switch (type) {
       case kAstI32:
         return builder_->Int32Constant(0);
       case kAstI64:
         return builder_->Int64Constant(0);
       case kAstF32:
         return builder_->Float32Constant(0);
       case kAstF64:
         return builder_->Float64Constant(0);
+      case kAstS128:
+        return builder_->DefaultS128Value();
       default:
         UNREACHABLE();
         return nullptr;
     }
   }
 
   char* indentation() {
     static const int kMaxIndent = 64;
     static char bytes[kMaxIndent + 1];
     for (int i = 0; i < kMaxIndent; ++i) bytes[i] = ' ';
@@ skipping 47 matching lines @@
     TRACE("wasm-decode %p...%p (module+%d, %d bytes) %s\n",
           reinterpret_cast<const void*>(start_),
           reinterpret_cast<const void*>(limit_), baserel(pc_),
           static_cast<int>(limit_ - start_), builder_ ? "graph building" : "");
 
     if (pc_ >= limit_) return;  // Nothing to do.
 
     while (true) {  // decoding loop.
       unsigned len = 1;
       WasmOpcode opcode = static_cast<WasmOpcode>(*pc_);
+      if (opcode == kSimdPrefix) {

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

Is it possible to make the prefix part of the main switch case below, and then
have a secondary switch in the function you mention in this comment?

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

Done.

+        // TODO(gdeepti): Piggybacking on unop/binop works for now, but this
+        // should be its own function to be able to parse more complex opcodes.
+        len++;
+        byte simd_index = *(pc_ + 1);
+        opcode = static_cast<WasmOpcode>(opcode << 8 | simd_index);
+      }
+
       TRACE("  @%-6d #%02x:%-20s|", startrel(pc_), opcode,
             WasmOpcodes::ShortOpcodeName(opcode));
 
       FunctionSig* sig = WasmOpcodes::Signature(opcode);
       if (sig) {
         // Fast case of a simple operator.
         TFNode* node;
         switch (sig->parameter_count()) {
           case 1: {
             Value val = Pop(0, sig->GetParam(0));
@@ skipping 1028 matching lines @@
 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
                                            const byte* start, const byte* end) {
   FunctionBody body = {nullptr, nullptr, nullptr, start, end};
   WasmFullDecoder decoder(zone, nullptr, body);
   return decoder.AnalyzeLoopAssignmentForTesting(start, num_locals);
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8