3646ee503d
Summary: There were a few issues with the previous setup: 1. The section sorting comparator used a declarative map of section names to determine the correct order, but it turns out we need to match on more than just names -- in particular, an upcoming diff will sort based on whether the S_ZERO_FILL flag is set. This diff changes the sorter to a more imperative but flexible form. 2. We were sorting OutputSections stored in a MapVector, which left the MapVector in an inconsistent state -- the wrong keys map to the wrong values! In practice, we weren't doing key lookups (only container iteration) after the sort, so this was fine, but it was still a dubious state of affairs. This diff copies the OutputSections to a vector before sorting them. 3. We were adding unneeded OutputSections to OutputSegments and then filtering them out later, which meant that we had to remember whether an OutputSegment was in a pre- or post-filtered state. This diff only adds the sections to the segments if they are needed. In addition to those major changes, two minor ones worth noting: 1. I renamed all OutputSection variable names to `osec`, to parallel `isec`. Previously we were using some inconsistent combination of `osec`, `os`, and `section`. 2. I added a check (and a test) for InputSections with names that clashed with those of our synthetic OutputSections. Reviewers: #lld-macho Subscribers: llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D81887
68 lines
1.9 KiB
C++
68 lines
1.9 KiB
C++
//===- OutputSegment.cpp --------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "OutputSegment.h"
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#include "InputSection.h"
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#include "MergedOutputSection.h"
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#include "SyntheticSections.h"
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#include "lld/Common/ErrorHandler.h"
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#include "lld/Common/Memory.h"
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#include "llvm/BinaryFormat/MachO.h"
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using namespace llvm;
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using namespace llvm::MachO;
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using namespace lld;
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using namespace lld::macho;
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static uint32_t initProt(StringRef name) {
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if (name == segment_names::text)
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return VM_PROT_READ | VM_PROT_EXECUTE;
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if (name == segment_names::pageZero)
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return 0;
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if (name == segment_names::linkEdit)
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return VM_PROT_READ;
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return VM_PROT_READ | VM_PROT_WRITE;
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}
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static uint32_t maxProt(StringRef name) {
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if (name == segment_names::pageZero)
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return 0;
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return VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
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}
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size_t OutputSegment::numNonHiddenSections() const {
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size_t count = 0;
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for (const OutputSection *osec : sections) {
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count += (!osec->isHidden() ? 1 : 0);
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}
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return count;
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}
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void OutputSegment::addOutputSection(OutputSection *osec) {
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osec->parent = this;
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sections.push_back(osec);
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}
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static llvm::DenseMap<StringRef, OutputSegment *> nameToOutputSegment;
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std::vector<OutputSegment *> macho::outputSegments;
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OutputSegment *macho::getOrCreateOutputSegment(StringRef name) {
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OutputSegment *&segRef = nameToOutputSegment[name];
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if (segRef != nullptr)
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return segRef;
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segRef = make<OutputSegment>();
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segRef->name = name;
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segRef->maxProt = maxProt(name);
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segRef->initProt = initProt(name);
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outputSegments.push_back(segRef);
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return segRef;
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}
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