VM: Enable collection of unoptimized code for optimized functions.

runtime/vm/code_patcher.cc

 // Copyright (c) 2012, 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/code_patcher.h"
 #include "vm/cpu.h"
 #include "vm/instructions.h"
 #include "vm/object.h"
 #include "vm/virtual_memory.h"
 
@@ skipping 34 matching lines @@
     buffer++;
   }
   CPU::FlushICache(code_address, num_bytes);
   // The buffer is not executed. No need to flush.
 }
 
 
 // The patch code buffer contains the jmp code which will be inserted at
 // entry point.
 void CodePatcher::PatchEntry(const Code& code) {
+  ASSERT(!IsEntryPatched(code));
   const uword patch_addr = code.GetEntryPatchPc();
   ASSERT(patch_addr != 0);
   JumpPattern jmp_entry(patch_addr, code);
   ASSERT(!jmp_entry.IsValid());
   const uword patch_buffer = code.GetPatchCodePc();
   ASSERT(patch_buffer != 0);
   JumpPattern jmp_patch(patch_buffer, code);
   ASSERT(jmp_patch.IsValid());
   const uword jump_target = jmp_patch.TargetAddress();
   intptr_t length = jmp_patch.pattern_length_in_bytes();
   {
     WritableInstructionsScope writable_code(patch_addr, length);
     WritableInstructionsScope writable_buffer(patch_buffer, length);
     SwapCode(jmp_patch.pattern_length_in_bytes(),
              reinterpret_cast<char*>(patch_addr),
              reinterpret_cast<char*>(patch_buffer));
     jmp_entry.SetTargetAddress(jump_target);
   }
 }
 
 
 // The entry point is a jmp instruction, the patch code buffer contains
 // original code, the entry point contains the jump instruction.
 void CodePatcher::RestoreEntry(const Code& code) {
+  if (!IsEntryPatched(code)) return;
   const uword patch_addr = code.GetEntryPatchPc();
   ASSERT(patch_addr != 0);
   JumpPattern jmp_entry(patch_addr, code);
   ASSERT(jmp_entry.IsValid());
   const uword jump_target = jmp_entry.TargetAddress();
   const uword patch_buffer = code.GetPatchCodePc();
   ASSERT(patch_buffer != 0);
   // 'patch_buffer' contains original entry code.
   JumpPattern jmp_patch(patch_buffer, code);
   ASSERT(!jmp_patch.IsValid());
@@ skipping 36 matching lines @@
     const uword obj_start = code.GetPointerOffsetAt(i) + code.EntryPoint();
     const uword obj_end  = obj_start + kWordSize;
     if ((obj_start < limit) && (obj_end > patch_addr)) {
       return false;
     }
   }
   return true;
 }
 
 }  // namespace dart