Revert of [wasm] Enforce that function bodies end with the \"end\" opcode....

Revert of [wasm] Enforce that function bodies end with the \"end\" opcode. (patchset #3 id:40001 of https://codereview.chromium.org/2630553002/ )

Reason for revert:
Caused tree to close by failing compilation:

https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20clang/builds/4451

Original issue's description:
> [wasm] Enforce that function bodies end with the \"end\" opcode.
>
> R=rossberg@chromium.org
> BUG=chromium:575167
>
> Review-Url: https://codereview.chromium.org/2630553002
> Cr-Commit-Position: refs/heads/master@{#42286}
> Committed: https://chromium.googlesource.com/v8/v8/+/fcc6e85ec6b01e5367795f98aff104b1ff23f619

TBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:575167

Review-Url: https://codereview.chromium.org/2628883006
Cr-Commit-Position: refs/heads/master@{#42287}

src/asmjs/asm-wasm-builder.cc

@@ -101,7 +101,6 @@ class AsmWasmBuilderImpl final : public AstVisitor<AsmWasmBuilderImpl> {
       uint32_t index = LookupOrInsertGlobal(fv->var, fv->type);
       foreign_init_function_->EmitWithVarInt(kExprSetGlobal, index);
     }
-    foreign_init_function_->Emit(kExprEnd);
   }
 
   Handle<FixedArray> GetForeignArgs() {
@@ -132,7 +131,6 @@ class AsmWasmBuilderImpl final : public AstVisitor<AsmWasmBuilderImpl> {
       return false;
     }
     BuildForeignInitFunction();
-    init_function_->Emit(kExprEnd);  // finish init function.
     return true;
   }
 
@@ -545,10 +543,6 @@ class AsmWasmBuilderImpl final : public AstVisitor<AsmWasmBuilderImpl> {
     RECURSE(VisitDeclarations(scope->declarations()));
     if (typer_failed_) return;
     RECURSE(VisitStatements(expr->body()));
-    if (scope_ == kFuncScope) {
-      // Finish the function-body scope block.
-      current_function_builder_->Emit(kExprEnd);
-    }
   }
 
   void VisitNativeFunctionLiteral(NativeFunctionLiteral* expr) {

src/wasm/function-body-decoder.cc

@@ -39,6 +39,8 @@ namespace wasm {
     error("Invalid opcode (enable with --" #flag ")");         \
     break;                                                     \
   }
+// TODO(titzer): this is only for intermediate migration.
+#define IMPLICIT_FUNCTION_END 1
 
 // An SsaEnv environment carries the current local variable renaming
 // as well as the current effect and control dependency in the TF graph.
@@ -491,14 +493,41 @@ class WasmFullDecoder : public WasmDecoder {
 
     if (failed()) return TraceFailed();
 
-    if (!control_.empty()) {
-      // Generate a better error message whether the unterminated control
-      // structure is the function body block or an innner structure.
-      if (control_.size() > 1) {
-        error(pc_, control_.back().pc, "unterminated control structure");
-      } else {
-        error("function body must end with \"end\" opcode.");
+#if IMPLICIT_FUNCTION_END
+    // With implicit end support (old style), the function block
+    // remains on the stack. Other control blocks are an error.
+    if (control_.size() > 1) {
+      error(pc_, control_.back().pc, "unterminated control structure");
+      return TraceFailed();
+    }
+
+    // Assume an implicit end to the function body block.
+    if (control_.size() == 1) {
+      Control* c = &control_.back();
+      if (ssa_env_->go()) {
+        FallThruTo(c);
+      }
+
+      if (c->end_env->go()) {
+        // Push the end values onto the stack.
+        stack_.resize(c->stack_depth);
+        if (c->merge.arity == 1) {
+          stack_.push_back(c->merge.vals.first);
+        } else {
+          for (unsigned i = 0; i < c->merge.arity; i++) {
+            stack_.push_back(c->merge.vals.array[i]);
+          }
+        }
+
+        TRACE("  @%-8d #xx:%-20s|", startrel(pc_), "ImplicitReturn");
+        SetEnv("function:end", c->end_env);
+        DoReturn();
+        TRACE("\n");
       }
+    }
+#else
+    if (!control_.empty()) {
+      error(pc_, control_.back().pc, "unterminated control structure");
       return TraceFailed();
     }
 
@@ -506,6 +535,7 @@ class WasmFullDecoder : public WasmDecoder {
       error("function body must end with \"end\" opcode.");
       return false;
     }
+#endif
 
     if (FLAG_trace_wasm_decode_time) {
       double ms = decode_timer.Elapsed().InMillisecondsF();

src/wasm/wasm-macro-gen.h

@@ -59,7 +59,6 @@
 // Control.
 //------------------------------------------------------------------------------
 #define WASM_NOP kExprNop
-#define WASM_END kExprEnd
 
 #define ARITY_0 0
 #define ARITY_1 1

src/wasm/wasm-text.cc

@@ -141,7 +141,7 @@ void wasm::PrintWasmText(const WasmModule *module,
   AccountingAllocator allocator;
   Zone zone(&allocator, ZONE_NAME);
   int line_nr = 0;
-  int control_depth = 1;
+  int control_depth = 0;
 
   // Print the function signature.
   os << "func";

test/cctest/wasm/test-run-wasm-interpreter.cc

@@ -219,7 +219,7 @@ TEST(Breakpoint_I32Add) {
 }
 
 TEST(Step_I32Mul) {
-  static const int kTraceLength = 5;
+  static const int kTraceLength = 4;
   byte code[] = {WASM_I32_MUL(WASM_GET_LOCAL(0), WASM_GET_LOCAL(1))};
 
   WasmRunner<int32_t, uint32_t, uint32_t> r(kExecuteInterpreted);

test/cctest/wasm/test-run-wasm-module.cc

@@ -63,12 +63,6 @@ void TestModuleException(Zone* zone, WasmModuleBuilder* builder) {
 
 void ExportAsMain(WasmFunctionBuilder* f) { f->ExportAs(CStrVector("main")); }
 
-#define EMIT_CODE_WITH_END(f, code)  \
-  do {                               \
-    f->EmitCode(code, sizeof(code)); \
-    f->Emit(kExprEnd);               \
-  } while (false)
-
 }  // namespace
 
 TEST(Run_WasmModule_Return114) {
@@ -82,7 +76,7 @@ TEST(Run_WasmModule_Return114) {
     WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
     ExportAsMain(f);
     byte code[] = {WASM_I32V_2(kReturnValue)};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModule(&zone, builder, kReturnValue);
   }
   Cleanup();
@@ -101,14 +95,14 @@ TEST(Run_WasmModule_CallAdd) {
     uint16_t param2 = 1;
     byte code1[] = {
         WASM_I32_ADD(WASM_GET_LOCAL(param1), WASM_GET_LOCAL(param2))};
-    EMIT_CODE_WITH_END(f1, code1);
+    f1->EmitCode(code1, sizeof(code1));
 
     WasmFunctionBuilder* f2 = builder->AddFunction(sigs.i_v());
 
     ExportAsMain(f2);
     byte code2[] = {
         WASM_CALL_FUNCTION(f1->func_index(), WASM_I32V_2(77), WASM_I32V_1(22))};
-    EMIT_CODE_WITH_END(f2, code2);
+    f2->EmitCode(code2, sizeof(code2));
     TestModule(&zone, builder, 99);
   }
   Cleanup();
@@ -127,7 +121,7 @@ TEST(Run_WasmModule_ReadLoadedDataSegment) {
     ExportAsMain(f);
     byte code[] = {
         WASM_LOAD_MEM(MachineType::Int32(), WASM_I32V_1(kDataSegmentDest0))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     byte data[] = {0xaa, 0xbb, 0xcc, 0xdd};
     builder->AddDataSegment(data, sizeof(data), kDataSegmentDest0);
     TestModule(&zone, builder, 0xddccbbaa);
@@ -155,7 +149,7 @@ TEST(Run_WasmModule_CheckMemoryIsZero) {
                 WASM_BRV(3, WASM_I32V_1(-1)),
                 WASM_INC_LOCAL_BY(localIndex, 4))),
         WASM_I32V_1(11))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModule(&zone, builder, 11);
   }
   Cleanup();
@@ -180,7 +174,7 @@ TEST(Run_WasmModule_CallMain_recursive) {
                                                WASM_INC_LOCAL(localIndex)),
                                 WASM_CALL_FUNCTION0(0)),
                        WASM_I32V_1(55))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModule(&zone, builder, 55);
   }
   Cleanup();
@@ -198,13 +192,13 @@ TEST(Run_WasmModule_Global) {
     WasmFunctionBuilder* f1 = builder->AddFunction(sigs.i_v());
     byte code1[] = {
         WASM_I32_ADD(WASM_GET_GLOBAL(global1), WASM_GET_GLOBAL(global2))};
-    EMIT_CODE_WITH_END(f1, code1);
+    f1->EmitCode(code1, sizeof(code1));
     WasmFunctionBuilder* f2 = builder->AddFunction(sigs.i_v());
     ExportAsMain(f2);
     byte code2[] = {WASM_SET_GLOBAL(global1, WASM_I32V_1(56)),
                     WASM_SET_GLOBAL(global2, WASM_I32V_1(41)),
                     WASM_RETURN1(WASM_CALL_FUNCTION0(f1->func_index()))};
-    EMIT_CODE_WITH_END(f2, code2);
+    f2->EmitCode(code2, sizeof(code2));
     TestModule(&zone, builder, 97);
   }
   Cleanup();
@@ -299,7 +293,7 @@ class WasmSerializationTest {
 
     WasmFunctionBuilder* f = builder->AddFunction(sigs.i_i());
     byte code[] = {WASM_GET_LOCAL(0), kExprI32Const, 1, kExprI32Add};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     f->ExportAs(CStrVector(kFunctionName));
 
     ZoneBuffer buffer(&zone_);
@@ -431,7 +425,7 @@ TEST(MemorySize) {
     WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
     ExportAsMain(f);
     byte code[] = {WASM_MEMORY_SIZE};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModule(&zone, builder, kExpectedValue);
   }
   Cleanup();
@@ -450,7 +444,7 @@ TEST(Run_WasmModule_MemSize_GrowMem) {
     ExportAsMain(f);
     byte code[] = {WASM_GROW_MEMORY(WASM_I32V_1(10)), WASM_DROP,
                    WASM_MEMORY_SIZE};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModule(&zone, builder, kExpectedValue);
   }
   Cleanup();
@@ -468,7 +462,7 @@ TEST(GrowMemoryZero) {
     WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
     ExportAsMain(f);
     byte code[] = {WASM_GROW_MEMORY(WASM_I32V(0))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModule(&zone, builder, kExpectedValue);
   }
   Cleanup();
@@ -539,7 +533,7 @@ TEST(TestInterruptLoop) {
                                     WASM_I32V(InterruptThread::signal_value_)),
                      WASM_BR(1))),
         WASM_I32V(121)};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     ZoneBuffer buffer(&zone);
     builder->WriteTo(buffer);
 
@@ -578,7 +572,7 @@ TEST(Run_WasmModule_GrowMemoryInIf) {
     ExportAsMain(f);
     byte code[] = {WASM_IF_ELSE_I(WASM_I32V(0), WASM_GROW_MEMORY(WASM_I32V(1)),
                                   WASM_I32V(12))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModule(&zone, builder, 12);
   }
   Cleanup();
@@ -600,7 +594,7 @@ TEST(Run_WasmModule_GrowMemOobOffset) {
     byte code[] = {WASM_GROW_MEMORY(WASM_I32V_1(1)),
                    WASM_STORE_MEM(MachineType::Int32(), WASM_I32V(index),
                                   WASM_I32V(value))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
     TestModuleException(&zone, builder);
   }
   Cleanup();
@@ -623,7 +617,7 @@ TEST(Run_WasmModule_GrowMemOobFixedIndex) {
                    WASM_STORE_MEM(MachineType::Int32(), WASM_I32V(index),
                                   WASM_I32V(value)),
                    WASM_LOAD_MEM(MachineType::Int32(), WASM_I32V(index))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
 
     HandleScope scope(isolate);
     ZoneBuffer buffer(&zone);
@@ -671,7 +665,7 @@ TEST(Run_WasmModule_GrowMemOobVariableIndex) {
                    WASM_STORE_MEM(MachineType::Int32(), WASM_GET_LOCAL(0),
                                   WASM_I32V(value)),
                    WASM_LOAD_MEM(MachineType::Int32(), WASM_GET_LOCAL(0))};
-    EMIT_CODE_WITH_END(f, code);
+    f->EmitCode(code, sizeof(code));
 
     HandleScope scope(isolate);
     ZoneBuffer buffer(&zone);
@@ -730,7 +724,7 @@ TEST(Run_WasmModule_Global_init) {
     WasmFunctionBuilder* f1 = builder->AddFunction(sigs.i_v());
     byte code[] = {
         WASM_I32_ADD(WASM_GET_GLOBAL(global1), WASM_GET_GLOBAL(global2))};
-    EMIT_CODE_WITH_END(f1, code);
+    f1->EmitCode(code, sizeof(code));
     ExportAsMain(f1);
     TestModule(&zone, builder, 999999);
   }
@@ -762,7 +756,7 @@ static void RunWasmModuleGlobalInitTest(ValueType type, CType expected) {
 
       WasmFunctionBuilder* f1 = builder->AddFunction(&sig);
       byte code[] = {WASM_GET_GLOBAL(global)};
-      EMIT_CODE_WITH_END(f1, code);
+      f1->EmitCode(code, sizeof(code));
       ExportAsMain(f1);
       TestModule(&zone, builder, expected);
     }

test/cctest/wasm/test-run-wasm.cc

@@ -1851,19 +1851,13 @@ static void TestBuildGraphForSimpleExpression(WasmOpcode opcode) {
   FunctionSig* sig = WasmOpcodes::Signature(opcode);
 
   if (sig->parameter_count() == 1) {
-    byte code[] = {WASM_NO_LOCALS, kExprGetLocal, 0, static_cast<byte>(opcode),
-                   WASM_END};
+    byte code[] = {WASM_NO_LOCALS, kExprGetLocal, 0, static_cast<byte>(opcode)};
     TestBuildingGraph(&zone, &jsgraph, nullptr, sig, nullptr, code,
                       code + arraysize(code));
   } else {
     CHECK_EQ(2, sig->parameter_count());
-    byte code[] = {WASM_NO_LOCALS,
-                   kExprGetLocal,
-                   0,
-                   kExprGetLocal,
-                   1,
-                   static_cast<byte>(opcode),
-                   WASM_END};
+    byte code[] = {WASM_NO_LOCALS,           kExprGetLocal, 0, kExprGetLocal, 1,
+                   static_cast<byte>(opcode)};
     TestBuildingGraph(&zone, &jsgraph, nullptr, sig, nullptr, code,
                       code + arraysize(code));
   }

test/cctest/wasm/test-wasm-breakpoints.cc

@@ -60,11 +60,11 @@ TEST(CollectPossibleBreakpoints) {
   Handle<WasmInstanceObject> instance = runner.module().instance_object();
   std::vector<debug::Location> locations;
   CheckLocations(instance->compiled_module(), {0, 0}, {1, 0},
-                 {{0, 1}, {0, 2}, {0, 4}, {0, 6}, {0, 7}});
+                 {{0, 1}, {0, 2}, {0, 4}, {0, 6}});
   CheckLocations(instance->compiled_module(), {0, 2}, {0, 4}, {{0, 2}});
   CheckLocations(instance->compiled_module(), {0, 2}, {0, 5}, {{0, 2}, {0, 4}});
-  CheckLocations(instance->compiled_module(), {0, 7}, {0, 8}, {{0, 7}});
-  CheckLocations(instance->compiled_module(), {0, 7}, {1, 0}, {{0, 7}});
-  CheckLocations(instance->compiled_module(), {0, 8}, {1, 0}, {});
-  CheckLocationsFail(instance->compiled_module(), {0, 9}, {1, 0});
+  CheckLocations(instance->compiled_module(), {0, 6}, {0, 7}, {{0, 6}});
+  CheckLocations(instance->compiled_module(), {0, 6}, {1, 0}, {{0, 6}});
+  CheckLocations(instance->compiled_module(), {0, 7}, {1, 0}, {});
+  CheckLocationsFail(instance->compiled_module(), {0, 8}, {1, 0});
 }

test/cctest/wasm/wasm-run-utils.h

@@ -509,18 +509,7 @@ class WasmFunctionCompiler : private GraphAndBuilders {
   uint32_t function_index() { return function_->func_index; }
 
   void Build(const byte* start, const byte* end) {
-    size_t locals_size = local_decls.Size();
-    size_t total_size = end - start + locals_size + 1;
-    byte* buffer = static_cast<byte*>(zone()->New(total_size));
-    // Prepend the local decls to the code.
-    local_decls.Emit(buffer);
-    // Emit the code.
-    memcpy(buffer + locals_size, start, end - start);
-    // Append an extra end opcode.
-    buffer[total_size - 1] = kExprEnd;
-
-    start = buffer;
-    end = buffer + total_size;
+    local_decls.Prepend(zone(), &start, &end);
 
     CHECK_GE(kMaxInt, end - start);
     int len = static_cast<int>(end - start);

test/debugger/debug/wasm/frame-inspection.js

@@ -15,8 +15,8 @@ var break_count = 0;
 const expected_frames = [
   // func-name; wasm?; pos; line; col
   ['call_debugger', false],        // --
-  ['wasm_2', true, 56, 2, 2],      // --
-  ['wasm_1', true, 52, 3, 2],      // --
+  ['wasm_2', true, 56, 2, 0],      // --
+  ['wasm_1', true, 52, 3, 0],      // --
   ['testFrameInspection', false],  // --
   ['', false]
 ];

test/inspector/debugger/wasm-scripts-expected.txt

 Check that inspector gets two wasm scripts at module creation time.
 Script #0 parsed. URL: v8://test/testFunction
 Script #1 parsed. URL: v8://test/runTestRunction
-Script #2 parsed. URL: wasm://wasm/wasm-e783515e/wasm-e783515e-0
-Script #3 parsed. URL: wasm://wasm/wasm-e783515e/wasm-e783515e-1
-Source for wasm://wasm/wasm-e783515e/wasm-e783515e-0:
+Script #2 parsed. URL: wasm://wasm/wasm-911a065e/wasm-911a065e-0
+Script #3 parsed. URL: wasm://wasm/wasm-911a065e/wasm-911a065e-1
+Source for wasm://wasm/wasm-911a065e/wasm-911a065e-0:
 func $nopFunction
-  nop
-end
+nop
 
-Source for wasm://wasm/wasm-e783515e/wasm-e783515e-1:
+Source for wasm://wasm/wasm-911a065e/wasm-911a065e-1:
 func $main
-  block
-    i32.const 2
-    drop
-  end
+block
+  i32.const 2
+  drop
 end
 

test/inspector/debugger/wasm-source-expected.txt

@@ -2,8 +2,8 @@ Check that inspector gets disassembled wasm code
 Paused on debugger!
 Number of frames: 5
 [0]     debugger;
-[1]   call 0
-[2]     call_indirect 2
+[1] call 0
+[2]   call_indirect 2
 [3]   instance.exports.main();
 [4] testFunction(module_bytes)
 Finished.

test/inspector/debugger/wasm-stack-expected.txt

@@ -2,8 +2,8 @@ Running testFunction with generated WASM bytes...
 Paused on 'debugger;'
 Number of frames: 5
   - [0] {"functionName":"call_debugger","function_lineNumber":1,"function_columnNumber":24,"lineNumber":2,"columnNumber":4}
-  - [1] {"functionName":"call_func","lineNumber":1,"columnNumber":2}
-  - [2] {"functionName":"main","lineNumber":2,"columnNumber":4}
+  - [1] {"functionName":"call_func","lineNumber":1,"columnNumber":0}
+  - [2] {"functionName":"main","lineNumber":2,"columnNumber":2}
   - [3] {"functionName":"testFunction","function_lineNumber":0,"function_columnNumber":21,"lineNumber":14,"columnNumber":19}
   - [4] {"functionName":"","function_lineNumber":0,"function_columnNumber":0,"lineNumber":0,"columnNumber":0}
 Getting v8-generated stack trace...

test/mjsunit/wasm/table.js

@@ -152,7 +152,7 @@ function assertTableIsValid(table) {
 
 (function TestSet() {
   let builder = new WasmModuleBuilder;
-  builder.addExport("wasm", builder.addFunction("", kSig_v_v).addBody([]));
+  builder.addExport("wasm", builder.addFunction("", kSig_v_v));
   builder.addExport("host", builder.addImport("test", "f", kSig_v_v));
   let {wasm, host} = builder.instantiate({test: {f() {}}}).exports;
 
@@ -200,7 +200,7 @@ function assertTableIsValid(table) {
 
 (function TestIndexing() {
   let builder = new WasmModuleBuilder;
-  builder.addExport("wasm", builder.addFunction("", kSig_v_v).addBody([]));
+  builder.addExport("wasm", builder.addFunction("", kSig_v_v));
   builder.addExport("host", builder.addImport("test", "f", kSig_v_v));
   let {wasm, host} = builder.instantiate({test: {f() {}}}).exports;
 
@@ -223,7 +223,7 @@ function assertTableIsValid(table) {
 
 (function TestGrow() {
   let builder = new WasmModuleBuilder;
-  builder.addExport("wasm", builder.addFunction("", kSig_v_v).addBody([]));
+  builder.addExport("wasm", builder.addFunction("", kSig_v_v));
   builder.addExport("host", builder.addImport("test", "f", kSig_v_v));
   let {wasm, host} = builder.instantiate({test: {f() {}}}).exports;
 

test/mjsunit/wasm/wasm-module-builder.js

@@ -98,8 +98,6 @@ class WasmFunctionBuilder {
 
   addBody(body) {
     this.body = body;
-    // Automatically add the end for the function block to the body.
-    body.push(kExprEnd);
     return this;
   }
 

test/unittests/value-serializer-unittest.cc

@@ -2439,10 +2439,10 @@ bool ValueSerializerTestWithWasm::g_saved_flag = false;
 // A simple module which exports an "increment" function.
 // Copied from test/mjsunit/wasm/incrementer.wasm.
 const unsigned char kIncrementerWasm[] = {
-    0,   97, 115, 109, 13, 0,  0, 0, 1,   6,   1,  96,  1,   127, 1,   127,
-    3,   2,  1,   0,   7,  13, 1, 9, 105, 110, 99, 114, 101, 109, 101, 110,
-    116, 0,  0,   10,  9,  1,  7, 0, 32,  0,   65, 1,   106, 11,
-};
+    0x00, 0x61, 0x73, 0x6d, 0x0d, 0x00, 0x00, 0x00, 0x01, 0x06, 0x01, 0x60,
+    0x01, 0x7f, 0x01, 0x7f, 0x03, 0x02, 0x01, 0x00, 0x07, 0x0d, 0x01, 0x09,
+    0x69, 0x6e, 0x63, 0x72, 0x65, 0x6d, 0x65, 0x6e, 0x74, 0x00, 0x00, 0x0a,
+    0x08, 0x01, 0x06, 0x00, 0x20, 0x00, 0x41, 0x01, 0x6a};
 
 TEST_F(ValueSerializerTestWithWasm, RoundTripWasmModule) {
   RoundTripTest(
@@ -2521,7 +2521,6 @@ const unsigned char kSerializedIncrementerWasm[] = {
     0x2f, 0x2f};
 
 TEST_F(ValueSerializerTestWithWasm, DecodeWasmModule) {
-  if (true) return;  // TODO(mtrofin): fix this test
   std::vector<uint8_t> raw(
       kSerializedIncrementerWasm,
       kSerializedIncrementerWasm + sizeof(kSerializedIncrementerWasm));
@@ -2542,7 +2541,6 @@ const unsigned char kSerializedIncrementerWasmWithInvalidCompiledData[] = {
     0x01, 0x06, 0x00, 0x20, 0x00, 0x41, 0x01, 0x6a, 0x00};
 
 TEST_F(ValueSerializerTestWithWasm, DecodeWasmModuleWithInvalidCompiledData) {
-  if (true) return;  // TODO(titzer): regenerate this test
   std::vector<uint8_t> raw(
       kSerializedIncrementerWasmWithInvalidCompiledData,
       kSerializedIncrementerWasmWithInvalidCompiledData +

test/unittests/wasm/function-body-decoder-unittest.cc

@@ -108,19 +108,7 @@ class FunctionBodyDecoderTest : public TestWithZone {
   // verification failures.
   void Verify(ErrorCode expected, FunctionSig* sig, const byte* start,
               const byte* end) {
-    size_t locals_size = local_decls.Size();
-    size_t total_size = end - start + locals_size + 1;
-    byte* buffer = static_cast<byte*>(zone()->New(total_size));
-    // Prepend the local decls to the code.
-    local_decls.Emit(buffer);
-    // Emit the code.
-    memcpy(buffer + locals_size, start, end - start);
-    // Append an extra end opcode.
-    buffer[total_size - 1] = kExprEnd;
-
-    start = buffer;
-    end = buffer + total_size;
-
+    local_decls.Prepend(zone(), &start, &end);
     // Verify the code.
     DecodeResult result = VerifyWasmCode(
         zone()->allocator(), module == nullptr ? nullptr : module->module, sig,
@@ -473,7 +461,11 @@ TEST_F(FunctionBodyDecoderTest, Block0Block0) {
 }
 
 TEST_F(FunctionBodyDecoderTest, Block0_end) {
-  EXPECT_FAILURE(v_v, WASM_EMPTY_BLOCK, kExprEnd);
+  EXPECT_VERIFIES(v_v, WASM_EMPTY_BLOCK, kExprEnd);
+}
+
+TEST_F(FunctionBodyDecoderTest, Block0_end_end) {
+  EXPECT_FAILURE(v_v, WASM_EMPTY_BLOCK, kExprEnd, kExprEnd);
 }
 
 TEST_F(FunctionBodyDecoderTest, Block1) {
@@ -726,13 +718,14 @@ TEST_F(FunctionBodyDecoderTest, IfNopElseNop) {
   EXPECT_VERIFIES(v_i, WASM_IF_ELSE(WASM_GET_LOCAL(0), WASM_NOP, WASM_NOP));
 }
 
-TEST_F(FunctionBodyDecoderTest, If_end) {
-  static const byte code[] = {kExprGetLocal, 0, WASM_IF_OP, kExprEnd};
+TEST_F(FunctionBodyDecoderTest, If_end_end) {
+  static const byte code[] = {kExprGetLocal, 0, WASM_IF_OP, kExprEnd, kExprEnd};
   EXPECT_VERIFIES_C(v_i, code);
 }
 
-TEST_F(FunctionBodyDecoderTest, If_end_end) {
-  static const byte code[] = {kExprGetLocal, 0, WASM_IF_OP, kExprEnd, kExprEnd};
+TEST_F(FunctionBodyDecoderTest, If_end_end_end) {
+  static const byte code[] = {kExprGetLocal, 0,        WASM_IF_OP,
+                              kExprEnd,      kExprEnd, kExprEnd};
   EXPECT_FAILURE_C(v_i, code);
 }
 

test/unittests/wasm/module-decoder-unittest.cc

@@ -933,7 +933,7 @@ TEST_F(WasmFunctionVerifyTest, Ok_v_v_empty) {
       kLocalF32,  // --
       6,
       kLocalF64,  // --
-      kExprEnd    // body
+      kExprNop    // body
   };
 
   FunctionResult result =

test/unittests/wasm/wasm-macro-gen-unittest.cc

@@ -49,7 +49,6 @@ TEST_F(WasmMacroGenTest, Constants) {
 
 TEST_F(WasmMacroGenTest, Statements) {
   EXPECT_SIZE(1, WASM_NOP);
-  EXPECT_SIZE(1, WASM_END);
 
   EXPECT_SIZE(4, WASM_SET_LOCAL(0, WASM_ZERO));