Add flag --use_slow_path to test slow paths. Started with implementation for implicit closure all...

runtime/vm/stub_code_ia32.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
 #include "vm/ic_data.h"
 #include "vm/object_store.h"
 #include "vm/pages.h"
 #include "vm/resolver.h"
 #include "vm/scavenger.h"
 #include "vm/stub_code.h"
 
 
 #define __ assembler->
 
 namespace dart {
 
 DEFINE_FLAG(bool, inline_alloc, true, "Inline allocation of objects.");
+DEFINE_FLAG(bool, use_slow_path, false,
+    "Set to true for debugging & verifying the slow paths.");
 
 // Input parameters:
 //   ESP : points to return address.
 //   ESP + 4 : address of last argument in argument array.
 //   ESP + 4*EDX : address of first argument in argument array.
 //   ESP + 4*EDX + 4 : address of return value.
 //   ECX : address of the runtime function to call.
 //   EDX : number of arguments to the call.
 // Must preserve callee saved registers EDI and EBX.
 static void GenerateCallRuntimeStub(Assembler* assembler) {
@@ skipping 1218 matching lines @@
   if (FLAG_inline_alloc &&
       PageSpace::IsPageAllocatableSize(closure_size + context_size)) {
     Label slow_case;
     Heap* heap = Isolate::Current()->heap();
     __ movl(EAX, Address::Absolute(heap->TopAddress()));
     __ leal(EBX, Address(EAX, closure_size));
     if (is_implicit_instance_closure) {
       __ movl(ECX, EBX);  // ECX: new context address.
       __ addl(EBX, Immediate(context_size));
     }
+    if (FLAG_use_slow_path) {
+      __ jmp(&slow_case);
+    }
     // Check if the allocation fits into the remaining space.
     // EAX: potential new closure object.
     // ECX: potential new context object (only if is_implicit_closure).
     // EBX: potential next object start.
     __ cmpl(EBX, Address::Absolute(heap->EndAddress()));
     __ j(ABOVE_EQUAL, &slow_case, Assembler::kNearJump);
 
     // Successfully allocated the object, now update top to point to
     // next object start and initialize the object.
     __ movl(Address::Absolute(heap->TopAddress()), EBX);
@@ skipping 247 matching lines @@
   // EAX: Target function.
   __ movl(EAX, FieldAddress(EAX, Function::code_offset()));
   __ movl(EAX, FieldAddress(EAX, Code::instructions_offset()));
   __ addl(EAX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(EAX);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32