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

src/asmjs/asm-wasm-builder.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/v8.h"
 
 // Required to get M_E etc. in MSVC.
 #if defined(_WIN32)
 #define _USE_MATH_DEFINES
 #endif
@@ skipping 83 matching lines @@
     }
     foreign_init_function_->ExportAs(
         CStrVector(AsmWasmBuilder::foreign_init_name));
     foreign_init_function_->SetSignature(b.Build());
     for (size_t pos = 0; pos < foreign_variables_.size(); ++pos) {
       foreign_init_function_->EmitGetLocal(static_cast<uint32_t>(pos));
       ForeignVariable* fv = &foreign_variables_[pos];
       uint32_t index = LookupOrInsertGlobal(fv->var, fv->type);
       foreign_init_function_->EmitWithVarInt(kExprSetGlobal, index);
     }
+    foreign_init_function_->Emit(kExprEnd);
   }
 
   Handle<FixedArray> GetForeignArgs() {
     Handle<FixedArray> ret = isolate_->factory()->NewFixedArray(
         static_cast<int>(foreign_variables_.size()));
     for (size_t i = 0; i < foreign_variables_.size(); ++i) {
       ForeignVariable* fv = &foreign_variables_[i];
       ret->set(static_cast<int>(i), *fv->name);
     }
     return ret;
@@ skipping 10 matching lines @@
       return false;
     }
     if (!typer_finished_ && !typer_failed_) {
       typer_->FailWithMessage("Module missing export section.");
       typer_failed_ = true;
     }
     if (typer_failed_) {
       return false;
     }
     BuildForeignInitFunction();
+    init_function_->Emit(kExprEnd);  // finish init function.
     return true;
   }
 
   void VisitVariableDeclaration(VariableDeclaration* decl) {}
 
   void VisitFunctionDeclaration(FunctionDeclaration* decl) {
     DCHECK_EQ(kModuleScope, scope_);
     DCHECK_NULL(current_function_builder_);
     FunctionLiteral* old_func = decl->fun();
     Zone zone(isolate_->allocator(), ZONE_NAME);
@@ skipping 392 matching lines @@
           DCHECK_NE(kWasmStmt, type);
           InsertParameter(scope->parameter(i), type, i);
         }
       } else {
         UNREACHABLE();
       }
     }
     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) {
     UNREACHABLE();
   }
 
   void VisitConditional(Conditional* expr) {
     DCHECK_EQ(kFuncScope, scope_);
     RECURSE(Visit(expr->condition()));
     // WASM ifs come with implicit blocks for both arms.
@@ skipping 1439 matching lines @@
   impl.builder_->WriteAsmJsOffsetTable(*asm_offsets_buffer);
   return {module_buffer, asm_offsets_buffer, success};
 }
 
 const char* AsmWasmBuilder::foreign_init_name = "__foreign_init__";
 const char* AsmWasmBuilder::single_function_name = "__single_function__";
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8