Reject lack of "use asm" marker in asm typer.

src/typing-asm.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"
 
 #include "src/typing-asm.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
@@ skipping 58 matching lines @@
 bool AsmTyper::Validate() {
   VisitAsmModule(root_);
   return valid_ && !HasStackOverflow();
 }
 
 
 void AsmTyper::VisitAsmModule(FunctionLiteral* fun) {
   Scope* scope = fun->scope();
   if (!scope->is_function_scope()) FAIL(fun, "not at function scope");
 
+  ExpressionStatement* use_asm = fun->body()->first()->AsExpressionStatement();
+  if (use_asm == NULL) FAIL(fun, "missing \"use asm\"");
+  Literal* use_asm_literal = use_asm->expression()->AsLiteral();
+  if (use_asm_literal == NULL) FAIL(fun, "missing \"use asm\"");
+  if (!use_asm_literal->raw_value()->AsString()->IsOneByteEqualTo("use asm"))
+    FAIL(fun, "missing \"use asm\"");
+
   // Module parameters.
   for (int i = 0; i < scope->num_parameters(); ++i) {
     Variable* param = scope->parameter(i);
     DCHECK(GetType(param) == NULL);
     SetType(param, Type::None(zone()));
   }
 
   ZoneList<Declaration*>* decls = scope->declarations();
 
   // Set all globals to type Any.
@@ skipping 1363 matching lines @@
 
 
 void AsmTyper::VisitRewritableAssignmentExpression(
     RewritableAssignmentExpression* expr) {
   RECURSE(Visit(expr->expression()));
 }
 
 
 }  // namespace internal
 }  // namespace v8