[wasm] Unreachability fix for br_table.

src/wasm/function-body-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/zone-containers.h"
@@ skipping 662 matching lines @@
           case kExprBlock: {
             // The break environment is the outer environment.
             BlockTypeOperand operand(this, pc_);
             SsaEnv* break_env = ssa_env_;
             PushBlock(break_env);
             SetEnv("block:start", Steal(break_env));
             SetBlockType(&control_.back(), operand);
             len = 1 + operand.length;
             break;
           }
           case kExprThrow: {

[rossberg, 2017/01/20 13:14:29]

Does this need an EndControl, too?

             CHECK_PROTOTYPE_OPCODE(wasm_eh_prototype);
             Value value = Pop(0, kWasmI32);
             BUILD(Throw, value.node);
             break;
           }
           case kExprTry: {
             CHECK_PROTOTYPE_OPCODE(wasm_eh_prototype);
             BlockTypeOperand operand(this, pc_);
             SsaEnv* outer_env = ssa_env_;
             SsaEnv* try_env = Steal(outer_env);
@@ skipping 252 matching lines @@
                 if (target >= control_.size()) {
                   error(pos, "improper branch in br_table");
                   break;
                 }
                 BreakTo(target);
               }
               // br_table ends the control flow like br.
               ssa_env_ = break_env;
             }
             len = 1 + iterator.length();
+            EndControl();
             break;
           }
           case kExprReturn: {
             DoReturn();
             break;
           }
           case kExprUnreachable: {
             BUILD(Unreachable, position());
             EndControl();
             break;
@@ skipping 1046 matching lines @@
 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
                                            const byte* start, const byte* end) {
   Decoder decoder(start, end);
   return WasmDecoder::AnalyzeLoopAssignment(&decoder, start,
                                             static_cast<int>(num_locals), zone);
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8