From e814a9b96b0da9b1155700cbddfaa08befe58cb3 Mon Sep 17 00:00:00 2001 From: "jkummerow@chromium.org" Date: Wed, 21 Aug 2013 15:31:03 +0000 Subject: [PATCH] Fix "Hole" leak in TryBuildConsolidatedElementLoad R=verwaest@chromium.org Review URL: https://codereview.chromium.org/23361007 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16262 ce2b1a6d-e550-0410-aec6-3dcde31c8c00 --- src/hydrogen.cc | 12 +++++++- test/mjsunit/regress/consolidated-holey-load.js | 40 +++++++++++++++++++++++++ 2 files changed, 51 insertions(+), 1 deletion(-) create mode 100644 test/mjsunit/regress/consolidated-holey-load.js diff --git a/src/hydrogen.cc b/src/hydrogen.cc index ef384a0..1fc6f08 100644 --- a/src/hydrogen.cc +++ b/src/hydrogen.cc @@ -5529,6 +5529,7 @@ HInstruction* HOptimizedGraphBuilder::TryBuildConsolidatedElementLoad( bool has_smi_or_object_maps = false; bool has_js_array_access = false; bool has_non_js_array_access = false; + bool has_seen_holey_elements = false; Handle most_general_consolidated_map; for (int i = 0; i < maps->length(); ++i) { Handle map = maps->at(i); @@ -5551,6 +5552,10 @@ HInstruction* HOptimizedGraphBuilder::TryBuildConsolidatedElementLoad( } else { return NULL; } + // Remember if we've ever seen holey elements. + if (IsHoleyElementsKind(map->elements_kind())) { + has_seen_holey_elements = true; + } // Remember the most general elements kind, the code for its load will // properly handle all of the more specific cases. if ((i == 0) || IsMoreGeneralElementsKindTransition( @@ -5562,10 +5567,15 @@ HInstruction* HOptimizedGraphBuilder::TryBuildConsolidatedElementLoad( if (!has_double_maps && !has_smi_or_object_maps) return NULL; HCheckMaps* check_maps = Add(object, maps); + // FAST_ELEMENTS is considered more general than FAST_HOLEY_SMI_ELEMENTS. + // If we've seen both, the consolidated load must use FAST_HOLEY_ELEMENTS. + ElementsKind consolidated_elements_kind = has_seen_holey_elements + ? GetHoleyElementsKind(most_general_consolidated_map->elements_kind()) + : most_general_consolidated_map->elements_kind(); HInstruction* instr = BuildUncheckedMonomorphicElementAccess( object, key, val, check_maps, most_general_consolidated_map->instance_type() == JS_ARRAY_TYPE, - most_general_consolidated_map->elements_kind(), + consolidated_elements_kind, false, NEVER_RETURN_HOLE, STANDARD_STORE); return instr; } diff --git a/test/mjsunit/regress/consolidated-holey-load.js b/test/mjsunit/regress/consolidated-holey-load.js new file mode 100644 index 0000000..ef8f1ef --- /dev/null +++ b/test/mjsunit/regress/consolidated-holey-load.js @@ -0,0 +1,40 @@ +// 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. + +// Flags: --allow-natives-syntax + +function foo(array) { + return array[0]; +} + +var a = [1, 2, , 4]; // Holey Smi elements. +var b = ["abcd", 0]; // Fast elements. +foo(b); // Observe fast elements first, or the IC will transition without +foo(a); // going polymorphic. +%OptimizeFunctionOnNextCall(foo); +var c = [, 0]; +assertEquals(undefined, foo(c)); // Elided hole check will leak the hole. -- 2.7.4