Temporarily disable optimization for StringWrappers to use native valueOf

V8 stores this information directly in the map of the wrapper, however,
it is not invalidated when the prototype of the wrapper is changed, so
once the bit is set, it is no longer possible to override valueOf.

This bug is currently hidden in Chrome since the i18n extension always
modifies the String.prototype, and so the optimization never kicks in.
Disabling the optimization temporarily allows for snapshotting i18n now.

BUG=v8:2855
R=yangguo@chromium.org
TEST=mjsunit/regress/regress-2855.js

Review URL: https://codereview.chromium.org/23060030

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16292 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index b73006a..2243296 100644 (file)
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -3079,11 +3079,6 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ cmp(r2, r3);
   __ b(ne, if_false);
 
-  // Set the bit in the map to indicate that it has been checked safe for
-  // default valueOf and set true result.
-  __ ldrb(r2, FieldMemOperand(r1, Map::kBitField2Offset));
-  __ orr(r2, r2, Operand(1 << Map::kStringWrapperSafeForDefaultValueOf));
-  __ strb(r2, FieldMemOperand(r1, Map::kBitField2Offset));
   __ jmp(if_true);
 
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);

diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index f08a269..bfe1f22 100644 (file)
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -3030,10 +3030,6 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
          ContextOperand(edx,
                         Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX));
   __ j(not_equal, if_false);
-  // Set the bit in the map to indicate that it has been checked safe for
-  // default valueOf and set true result.
-  __ or_(FieldOperand(ebx, Map::kBitField2Offset),
-         Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
   __ jmp(if_true);
 
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);

diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index b60502c..9da8e54 100644 (file)
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -3099,11 +3099,6 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ lw(a3, ContextOperand(a3, Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX));
   __ Branch(if_false, ne, a2, Operand(a3));
 
-  // Set the bit in the map to indicate that it has been checked safe for
-  // default valueOf and set true result.
-  __ lbu(a2, FieldMemOperand(a1, Map::kBitField2Offset));
-  __ Or(a2, a2, Operand(1 << Map::kStringWrapperSafeForDefaultValueOf));
-  __ sb(a2, FieldMemOperand(a1, Map::kBitField2Offset));
   __ jmp(if_true);
 
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);

diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 6333e87..9f2074c 100644 (file)
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -3007,10 +3007,6 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ cmpq(rcx,
           ContextOperand(rdx, Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX));
   __ j(not_equal, if_false);
-  // Set the bit in the map to indicate that it has been checked safe for
-  // default valueOf and set true result.
-  __ or_(FieldOperand(rbx, Map::kBitField2Offset),
-         Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
   __ jmp(if_true);
 
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);

diff --git a/test/mjsunit/regress/regress-2855.js b/test/mjsunit/regress/regress-2855.js
new file mode 100644 (file)
index 0000000..ac721af
--- /dev/null
+++ b/test/mjsunit/regress/regress-2855.js
@@ -0,0 +1,41 @@
+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+function foo(a) {
+  for (var i = 0; i < 100; ++i)
+    a = new String(a);
+  return a;
+}
+
+var expected = "hello";
+for (var i = 0; i < 4; ++i) {
+  if (i == 2) {
+    String.prototype.valueOf = function() { return 42; }
+    expected = "42";
+  }
+  assertEquals(expected, "" + foo("hello"));
+}