Simd i8x16.extract_lane_s instruction implementation. (#802)

Including:
1. All necessary code for SIMD lanes accessing.
2. i8x16.extract_lane_s implementation.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/wast-parser.cc b/src/wast-parser.cc
index d62a277b..cd9b7bb1 100644
--- a/src/wast-parser.cc
+++ b/src/wast-parser.cc
@@ -173,6 +173,7 @@ bool IsPlainInstr(TokenType token_type) {
     case TokenType::AtomicWake:
     case TokenType::AtomicWait:
     case TokenType::Ternary:
+    case TokenType::SimdLaneOp:
       return true;
     default:
       return false;
@@ -1495,6 +1496,15 @@ Result WastParser::ParsePlainInstr(std::unique_ptr<Expr>* out_expr) {
       break;
     }
 
+    case TokenType::SimdLaneOp: {
+      Token token = Consume();
+      ErrorUnlessOpcodeEnabled(token);
+      uint64_t lane_idx;
+      CHECK_RESULT(ParseNat(&lane_idx));
+      out_expr->reset(new SimdLaneOpExpr(token.opcode(), lane_idx, loc));
+      break;
+    }
+
     default:
       assert(
           !"ParsePlainInstr should only be called when IsPlainInstr() is true");