From cac5a7e871f1f346b317894359ad06fa7bd67fba Mon Sep 17 00:00:00 2001 From: Vladimir Marko Date: Mon, 22 Feb 2016 10:39:50 +0000 Subject: Optimizing: Improve const-string code generation. For strings in the boot image, use either direct pointers or pc-relative addresses. For other strings, use PC-relative access to the dex cache arrays for AOT and direct address of the string's dex cache slot for JIT. For aosp_flounder-userdebug: - 32-bit boot.oat: -692KiB (-0.9%) - 64-bit boot.oat: -948KiB (-1.1%) - 32-bit dalvik cache total: -900KiB (-0.9%) - 64-bit dalvik cache total: -3672KiB (-1.5%) (contains more files than the 32-bit dalvik cache) For aosp_flounder-userdebug forced to compile PIC: - 32-bit boot.oat: -380KiB (-0.5%) - 64-bit boot.oat: -928KiB (-1.0%) - 32-bit dalvik cache total: -468KiB (-0.4%) - 64-bit dalvik cache total: -1928KiB (-0.8%) (contains more files than the 32-bit dalvik cache) Bug: 26884697 Change-Id: Iec7266ce67e6fedc107be78fab2e742a8dab2696 --- compiler/utils/string_reference.h | 64 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 compiler/utils/string_reference.h (limited to 'compiler/utils/string_reference.h') diff --git a/compiler/utils/string_reference.h b/compiler/utils/string_reference.h new file mode 100644 index 0000000000..72552f21aa --- /dev/null +++ b/compiler/utils/string_reference.h @@ -0,0 +1,64 @@ +/* + * Copyright (C) 2016 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. + */ + +#ifndef ART_COMPILER_UTILS_STRING_REFERENCE_H_ +#define ART_COMPILER_UTILS_STRING_REFERENCE_H_ + +#include + +#include "base/logging.h" +#include "utf-inl.h" + +namespace art { + +class DexFile; + +// A string is uniquely located by its DexFile and the string_ids_ table index into that DexFile. +struct StringReference { + StringReference(const DexFile* file, uint32_t index) : dex_file(file), string_index(index) { } + + const DexFile* dex_file; + uint32_t string_index; +}; + +// Compare the actual referenced string values. Used for string reference deduplication. +struct StringReferenceValueComparator { + bool operator()(StringReference sr1, StringReference sr2) const { + // Note that we want to deduplicate identical strings even if they are referenced + // by different dex files, so we need some (any) total ordering of strings, rather + // than references. However, the references should usually be from the same dex file, + // so we choose the dex file string ordering so that we can simply compare indexes + // and avoid the costly string comparison in the most common case. + if (sr1.dex_file == sr2.dex_file) { + // Use the string order enforced by the dex file verifier. + DCHECK_EQ( + sr1.string_index < sr2.string_index, + CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues( + sr1.dex_file->GetStringData(sr1.dex_file->GetStringId(sr1.string_index)), + sr1.dex_file->GetStringData(sr2.dex_file->GetStringId(sr2.string_index))) < 0); + return sr1.string_index < sr2.string_index; + } else { + // Cannot compare indexes, so do the string comparison. + return CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues( + sr1.dex_file->GetStringData(sr1.dex_file->GetStringId(sr1.string_index)), + sr1.dex_file->GetStringData(sr2.dex_file->GetStringId(sr2.string_index))) < 0; + } + } +}; + +} // namespace art + +#endif // ART_COMPILER_UTILS_STRING_REFERENCE_H_ -- cgit v1.2.3-59-g8ed1b