From 2ef645ba50544b879a82ea30e606f18c9af98917 Mon Sep 17 00:00:00 2001 From: David Brazdil Date: Wed, 17 Jun 2015 18:20:52 +0100 Subject: [PATCH] ART: Allow PackedSwitch instructions with zero targets Optimizing and the interpreter wrongly assumed that a PackedSwitch always has at least one target. This patch removes the corresponding DCHECKs and adds a regression test case. This is a resubmission of CL I32b7033ed38de6f1d1a6ee5d5bf12f3a47c9b37e Bug: 21863783 Change-Id: I04e6e124bdd16591ba27c79490e6ce183c36b691 --- compiler/optimizing/builder.cc | 14 +++++++-- runtime/interpreter/interpreter_common.h | 5 +++- test/501-regression-packed-switch/expected.txt | 0 test/501-regression-packed-switch/info.txt | 2 ++ test/501-regression-packed-switch/smali/Test.smali | 29 +++++++++++++++++++ test/501-regression-packed-switch/src/Main.java | 33 ++++++++++++++++++++++ 6 files changed, 80 insertions(+), 3 deletions(-) create mode 100644 test/501-regression-packed-switch/expected.txt create mode 100644 test/501-regression-packed-switch/info.txt create mode 100644 test/501-regression-packed-switch/smali/Test.smali create mode 100644 test/501-regression-packed-switch/src/Main.java diff --git a/compiler/optimizing/builder.cc b/compiler/optimizing/builder.cc index 1f9287cbf..cdd7636c0 100644 --- a/compiler/optimizing/builder.cc +++ b/compiler/optimizing/builder.cc @@ -1210,14 +1210,20 @@ bool HGraphBuilder::NeedsAccessCheck(uint32_t type_index) const { } void HGraphBuilder::BuildPackedSwitch(const Instruction& instruction, uint32_t dex_pc) { + // Verifier guarantees that the payload for PackedSwitch contains: + // (a) number of entries (may be zero) + // (b) first and lowest switch case value (entry 0, always present) + // (c) list of target pcs (entries 1 <= i <= N) SwitchTable table(instruction, dex_pc, false); // Value to test against. HInstruction* value = LoadLocal(instruction.VRegA(), Primitive::kPrimInt); + // Retrieve number of entries. uint16_t num_entries = table.GetNumEntries(); - // There should be at least one entry here. - DCHECK_GT(num_entries, 0U); + if (num_entries == 0) { + return; + } // Chained cmp-and-branch, starting from starting_key. int32_t starting_key = table.GetEntryAt(0); @@ -1229,6 +1235,10 @@ void HGraphBuilder::BuildPackedSwitch(const Instruction& instruction, uint32_t d } void HGraphBuilder::BuildSparseSwitch(const Instruction& instruction, uint32_t dex_pc) { + // Verifier guarantees that the payload for SparseSwitch contains: + // (a) number of entries (may be zero) + // (b) sorted key values (entries 0 <= i < N) + // (c) target pcs corresponding to the switch values (entries N <= i < 2*N) SwitchTable table(instruction, dex_pc, true); // Value to test against. diff --git a/runtime/interpreter/interpreter_common.h b/runtime/interpreter/interpreter_common.h index 6fafcd161..0124d9037 100644 --- a/runtime/interpreter/interpreter_common.h +++ b/runtime/interpreter/interpreter_common.h @@ -295,7 +295,10 @@ static inline int32_t DoPackedSwitch(const Instruction* inst, const ShadowFrame& int32_t test_val = shadow_frame.GetVReg(inst->VRegA_31t(inst_data)); DCHECK_EQ(switch_data[0], static_cast(Instruction::kPackedSwitchSignature)); uint16_t size = switch_data[1]; - DCHECK_GT(size, 0); + if (size == 0) { + // Empty packed switch, move forward by 3 (size of PACKED_SWITCH). + return 3; + } const int32_t* keys = reinterpret_cast(&switch_data[2]); DCHECK(IsAligned<4>(keys)); int32_t first_key = keys[0]; diff --git a/test/501-regression-packed-switch/expected.txt b/test/501-regression-packed-switch/expected.txt new file mode 100644 index 000000000..e69de29bb diff --git a/test/501-regression-packed-switch/info.txt b/test/501-regression-packed-switch/info.txt new file mode 100644 index 000000000..fbd93fa81 --- /dev/null +++ b/test/501-regression-packed-switch/info.txt @@ -0,0 +1,2 @@ +Regression test for the interpreter and optimizing's builder which used +to trip when compiled code contained a packed switch with no targets. diff --git a/test/501-regression-packed-switch/smali/Test.smali b/test/501-regression-packed-switch/smali/Test.smali new file mode 100644 index 000000000..8756ed5f2 --- /dev/null +++ b/test/501-regression-packed-switch/smali/Test.smali @@ -0,0 +1,29 @@ +# +# Copyright (C) 2015 The Android Open Source Project +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +.class public LTest; + +.super Ljava/lang/Object; + +.method public static EmptyPackedSwitch(I)I + .registers 1 + packed-switch v0, :pswitch_data_6a + const/4 v0, 0x5 + return v0 + + :pswitch_data_6a + .packed-switch 0x0 + .end packed-switch +.end method diff --git a/test/501-regression-packed-switch/src/Main.java b/test/501-regression-packed-switch/src/Main.java new file mode 100644 index 000000000..b80bc62c5 --- /dev/null +++ b/test/501-regression-packed-switch/src/Main.java @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2015 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +import java.lang.reflect.Method; +import java.lang.reflect.Type; + +public class Main { + + // Workaround for b/18051191. + class InnerClass {} + + public static void main(String args[]) throws Exception { + Class c = Class.forName("Test"); + Method m = c.getMethod("EmptyPackedSwitch", new Class[] { int.class }); + Integer result = (Integer) m.invoke(null, new Integer(42)); + if (result != 5) { + throw new Error("Expected 5, got " + result); + } + } +} -- 2.11.0