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a8febf2283
We already do this for shstrtab, so might as well do it for strtab. This extracts the string table building code into a separate class. The idea is to use it for other object formats too. I mostly wanted to do this for the general principle, but it does save a little bit on object file size. I tried this on a clang bootstrap and saved 0.54% on the sum of object file sizes (1.14 MB out of 212 MB for a release build). Differential Revision: http://reviews.llvm.org/D3533 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207670 91177308-0d34-0410-b5e6-96231b3b80d8
52 lines
1.4 KiB
C++
52 lines
1.4 KiB
C++
//===-- StringTableBuilder.cpp - String table building utility ------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Object/StringTableBuilder.h"
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using namespace llvm;
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static bool compareBySuffix(StringRef a, StringRef b) {
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size_t sizeA = a.size();
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size_t sizeB = b.size();
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size_t len = std::min(sizeA, sizeB);
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for (size_t i = 0; i < len; ++i) {
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char ca = a[sizeA - i - 1];
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char cb = b[sizeB - i - 1];
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if (ca != cb)
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return ca > cb;
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}
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return sizeA > sizeB;
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}
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void StringTableBuilder::finalize() {
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SmallVector<StringRef, 8> Strings;
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for (auto i = StringIndexMap.begin(), e = StringIndexMap.end(); i != e; ++i)
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Strings.push_back(i->getKey());
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std::sort(Strings.begin(), Strings.end(), compareBySuffix);
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// FIXME: Starting with a null byte is ELF specific. Generalize this so we
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// can use the class with other object formats.
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StringTable += '\x00';
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StringRef Previous;
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for (StringRef s : Strings) {
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if (Previous.endswith(s)) {
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StringIndexMap[s] = StringTable.size() - 1 - s.size();
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continue;
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}
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StringIndexMap[s] = StringTable.size();
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StringTable += s;
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StringTable += '\x00';
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Previous = s;
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}
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}
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