Disconnects code objects from infrequently used unoptimized functions.

runtime/vm/stub_code_arm.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_ARM)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 1571 matching lines @@
   __ LoadFromOffset(kWord, R0, R6, target_offset);
   __ LoadFromOffset(kWord, R1, R6, count_offset);
   __ adds(R1, R1, ShifterOperand(Smi::RawValue(1)));
   __ StoreToOffset(kWord, R1, R6, count_offset);
   __ b(&call_target_function, VC);  // No overflow.
   __ LoadImmediate(R1, Smi::RawValue(Smi::kMaxValue));
   __ StoreToOffset(kWord, R1, R6, count_offset);
 
   __ Bind(&call_target_function);
   // R0: target function.
-  __ ldr(R0, FieldAddress(R0, Function::code_offset()));
-  __ ldr(R0, FieldAddress(R0, Code::instructions_offset()));
+  __ ldr(R1, FieldAddress(R0, Function::code_offset()));
+  if (FLAG_collect_code) {
+    // If we are collecting code, the code object may be null.
+    Label is_compiled;
+    __ CompareImmediate(R1, reinterpret_cast<intptr_t>(Object::null()));
+    __ b(&is_compiled, NE);
+    __ EnterStubFrame();
+    // Preserve arg desc. and IC data object.
+    __ PushList((1 << R4) | (1 << R5));
+    __ Push(R0);  // Pass function.
+    __ CallRuntime(kCompileFunctionRuntimeEntry, 1);
+    __ Pop(R0);  // Discard argument.
+    __ PopList((1 << R4) | (1 << R5));  // Restore arg desc. and IC data.
+    __ LeaveStubFrame();
+    // R0: target function.
+    __ ldr(R1, FieldAddress(R0, Function::code_offset()));
+    __ Bind(&is_compiled);
+  }
+  __ ldr(R0, FieldAddress(R1, Code::instructions_offset()));
   __ AddImmediate(R0, Instructions::HeaderSize() - kHeapObjectTag);
   __ bx(R0);
 
   // Instance in R0, return its class-id in R0 as Smi.
   __ Bind(&get_class_id_as_smi);
 
   // Test if Smi -> load Smi class for comparison.
   __ tst(R0, ShifterOperand(kSmiTagMask));
   __ mov(R0, ShifterOperand(Smi::RawValue(kSmiCid)), EQ);
   __ bx(LR, EQ);
@@ skipping 502 matching lines @@
   __ ldr(left, Address(SP, 4 * kWordSize));
   __ ldr(right, Address(SP, 3 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ PopList((1 << R0) | (1 << R1) | (1 << R2));
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM