Disconnects code objects from infrequently used unoptimized functions.

runtime/vm/stub_code_ia32.cc

 // Copyright (c) 2013, 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/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 1595 matching lines @@
   const intptr_t target_offset = ICData::TargetIndexFor(num_args) * kWordSize;
   const intptr_t count_offset = ICData::CountIndexFor(num_args) * kWordSize;
   __ movl(EAX, Address(EBX, target_offset));
   __ addl(Address(EBX, count_offset), Immediate(Smi::RawValue(1)));
   __ j(NO_OVERFLOW, &call_target_function, Assembler::kNearJump);
   __ movl(Address(EBX, count_offset),
           Immediate(Smi::RawValue(Smi::kMaxValue)));
 
   __ Bind(&call_target_function);
   // EAX: Target function.
-  __ movl(EAX, FieldAddress(EAX, Function::code_offset()));
-  __ movl(EAX, FieldAddress(EAX, Code::instructions_offset()));
+  Label is_compiled;
+  __ movl(EBX, FieldAddress(EAX, Function::code_offset()));
+  if (FLAG_collect_code) {
+    // If code might be GC'd, then EBX might be null. If it is, recompile.
+    __ cmpl(EBX, raw_null);
+    __ j(NOT_EQUAL, &is_compiled, Assembler::kNearJump);
+    __ EnterStubFrame();
+    __ pushl(EDX);  // Preserve arguments descriptor array.
+    __ pushl(ECX);  // Preserve IC data object.
+    __ pushl(EAX);  // Pass function.
+    __ CallRuntime(kCompileFunctionRuntimeEntry, 1);
+    __ popl(EAX);  // Restore function.
+    __ popl(ECX);  // Restore IC data array.
+    __ popl(EDX);  // Restore arguments descriptor array.
+    __ LeaveFrame();
+    __ movl(EBX, FieldAddress(EAX, Function::code_offset()));
+    __ Bind(&is_compiled);
+  }
+  __ movl(EAX, FieldAddress(EBX, Code::instructions_offset()));
   __ addl(EAX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(EAX);
 
   // Instance in EAX, return its class-id in EAX as Smi.
   __ Bind(&get_class_id_as_smi);
   Label not_smi;
   // Test if Smi -> load Smi class for comparison.
   __ testl(EAX, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, &not_smi, Assembler::kNearJump);
   __ movl(EAX, Immediate(Smi::RawValue(kSmiCid)));
@@ skipping 545 matching lines @@
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ popl(temp);
   __ popl(right);
   __ popl(left);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32