Restrict the syntax that we aggressively optimize.

src/fast-codegen.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 71 matching lines @@
 }
 
 
 void FastCodeGenSyntaxChecker::VisitDeclarations(
     ZoneList<Declaration*>* decls) {
   if (!decls->is_empty()) BAILOUT("Function has declarations");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitStatements(ZoneList<Statement*>* stmts) {
-  for (int i = 0, len = stmts->length(); i < len; i++) {
-    Visit(stmts->at(i));
-    CHECK_BAILOUT;
+  if (stmts->length() != 1) {
+    BAILOUT("Function body is not a singleton statement.");
   }
+  Visit(stmts->at(0));
 }
 
 
 void FastCodeGenSyntaxChecker::VisitDeclaration(Declaration* decl) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenSyntaxChecker::VisitBlock(Block* stmt) {
   VisitStatements(stmt->statements());
@@ skipping 163 matching lines @@
 
   // We will only specialize for fields on the object itself.
   // Expression::IsPropertyName implies that the name is a literal
   // symbol but we do not assume that.
   Literal* key = prop->key()->AsLiteral();
   if (key != NULL && key->handle()->IsString()) {
     Handle<Object> receiver = info()->receiver();
     Handle<String> name = Handle<String>::cast(key->handle());
     LookupResult lookup;
     receiver->Lookup(*name, &lookup);
+    if (!lookup.IsValid()) {
+      BAILOUT("Assigned property not found at compile time");
+    }
     if (lookup.holder() != *receiver) BAILOUT("Non-own property assignment");
     if (!lookup.type() == FIELD) BAILOUT("Non-field property assignment");
   } else {
     UNREACHABLE();
     BAILOUT("Unexpected non-string-literal property key");
   }
 
   Visit(expr->value());
 }
 
@@ skipping 15 matching lines @@
 
   // We will only specialize for fields on the object itself.
   // Expression::IsPropertyName implies that the name is a literal
   // symbol but we do not assume that.
   Literal* key = expr->key()->AsLiteral();
   if (key != NULL && key->handle()->IsString()) {
     Handle<Object> receiver = info()->receiver();
     Handle<String> name = Handle<String>::cast(key->handle());
     LookupResult lookup;
     receiver->Lookup(*name, &lookup);
+    if (!lookup.IsValid()) {
+      BAILOUT("Referenced property not found at compile time");
+    }
     if (lookup.holder() != *receiver) BAILOUT("Non-own property reference");
     if (!lookup.type() == FIELD) BAILOUT("Non-field property reference");
   } else {
     UNREACHABLE();
     BAILOUT("Unexpected non-string-literal property key");
   }
 }
 
 
 void FastCodeGenSyntaxChecker::VisitCall(Call* expr) {
@@ skipping 29 matching lines @@
     case Token::OR:
       BAILOUT("BinaryOperation OR");
     case Token::AND:
       BAILOUT("BinaryOperation AND");
 
     case Token::BIT_OR:
       // We support expressions nested on the left because they only require
       // a pair of registers to keep all intermediate values in registers
       // (i.e., the expression stack has height no more than two).
       if (!expr->right()->IsLeaf()) BAILOUT("expression nested on right");
+
+      // We do not allow subexpressions with side effects because we
+      // (currently) bail out to the beginning of the full function.  The
+      // only expressions with side effects that we would otherwise handle
+      // are assignments.
+      if (expr->left()->AsAssignment() != NULL ||
+          expr->right()->AsAssignment() != NULL) {
+        BAILOUT("subexpression of binary operation has side effects");
+      }
+
       Visit(expr->left());
       CHECK_BAILOUT;
       Visit(expr->right());
       break;
 
     case Token::BIT_XOR:
       BAILOUT("BinaryOperation BIT_XOR");
     case Token::BIT_AND:
       BAILOUT("BinaryOperation BIT_AND");
     case Token::SHL:
@@ skipping 335 matching lines @@
 
 
 void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   UNREACHABLE();
 }
 
 #undef __
 
 
 } }  // namespace v8::internal