Revision: 6031
Author: [email protected]
Date: Wed Dec 15 06:35:46 2010
Log: Fix issue 982.
When splitting at the beginning of a use interval assign coinciding
position to the split child instead of leaving it to parent.
BUG=v8:982
Review URL: http://codereview.chromium.org/5898001
http://code.google.com/p/v8/source/detail?r=6031
Added:
/branches/bleeding_edge/test/mjsunit/regress/regress-982.js
Modified:
/branches/bleeding_edge/src/lithium-allocator.cc
=======================================
--- /dev/null
+++ /branches/bleeding_edge/test/mjsunit/regress/regress-982.js Wed Dec 15
06:35:46 2010
@@ -0,0 +1,45 @@
+// Copyright 2010 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 f(a) {
+ return {className: 'xxx'};
+};
+
+var x = 1;
+
+function g(active) {
+ for (i = 1; i <= 20000; i++) {
+ if (i == active) {
+ x = i;
+ if (f("" + i) != null) { }
+ } else {
+ if (f("" + i) != null) { }
+ }
+ }
+}
+
+g(0);
=======================================
--- /branches/bleeding_edge/src/lithium-allocator.cc Fri Dec 10 06:25:10
2010
+++ /branches/bleeding_edge/src/lithium-allocator.cc Wed Dec 15 06:35:46
2010
@@ -296,13 +296,21 @@
// position is contained in one of the intervals in the chain, we
// split that interval and use the first part.
UseInterval* current = FirstSearchIntervalForPosition(position);
+
+ // If the split position coincides with the beginning of a use interval
+ // we need to split use positons in a special way.
+ bool split_at_start = false;
+
while (current != NULL) {
if (current->Contains(position)) {
current->SplitAt(position);
break;
}
UseInterval* next = current->next();
- if (next->start().Value() >= position.Value()) break;
+ if (next->start().Value() >= position.Value()) {
+ split_at_start = (next->start().Value() == position.Value());
+ break;
+ }
current = next;
}
@@ -319,9 +327,19 @@
// position after it.
UsePosition* use_after = first_pos_;
UsePosition* use_before = NULL;
- while (use_after != NULL && use_after->pos().Value() <=
position.Value()) {
- use_before = use_after;
- use_after = use_after->next();
+ if (split_at_start) {
+ // The split position coincides with the beginning of a use interval
(the
+ // end of a lifetime hole). Use at this position should be attributed
to
+ // the split child because split child owns use interval covering it.
+ while (use_after != NULL && use_after->pos().Value() <
position.Value()) {
+ use_before = use_after;
+ use_after = use_after->next();
+ }
+ } else {
+ while (use_after != NULL && use_after->pos().Value() <=
position.Value()) {
+ use_before = use_after;
+ use_after = use_after->next();
+ }
}
// Partition original use positions to the two live ranges.
--
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