[turbofan] Make sure there is space for lazy deopt patching before the constant pool.

BUG=chromium:446647
LOG=n
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/874863003

Cr-Commit-Position: refs/heads/master@{#26327}

src/compiler/code-generator.cc

@@ -85,8 +85,6 @@ Handle<Code> CodeGenerator::GenerateCode() {
     }
   }
 
-  FinishCode(masm());
-
   // Ensure there is space for lazy deoptimization in the code.
   if (!info->IsStub()) {
     int target_offset = masm()->pc_offset() + Deoptimizer::patch_size();
@@ -95,6 +93,8 @@ Handle<Code> CodeGenerator::GenerateCode() {
     }
   }
 
+  FinishCode(masm());
+
   safepoints()->Emit(masm(), frame()->GetSpillSlotCount());
 
   // TODO(titzer): what are the right code flags here?

test/mjsunit/compiler/regress-446647.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --always-opt --turbo-filter=* --turbo-deoptimization --allow-natives-syntax
+
+function f(a,b) {
+  a%b
+};
+
+f({ toString : function() { %DeoptimizeFunction(f); }});