55e9eb416e
The order file indicates how input sections should be sorted within each output section, based on the symbols contained within those sections. This diff sets the stage for implementing and testing `.subsections_via_symbols`, where we will break up InputSections by each symbol and sort them more granularly. Reviewed By: smeenai Differential Revision: https://reviews.llvm.org/D79668
110 lines
3.3 KiB
C++
110 lines
3.3 KiB
C++
//===- OutputSection.h ------------------------------------------*- C++ -*-===//
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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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#ifndef LLD_MACHO_OUTPUT_SECTION_H
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#define LLD_MACHO_OUTPUT_SECTION_H
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#include "lld/Common/LLVM.h"
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#include "llvm/ADT/DenseMap.h"
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namespace lld {
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namespace macho {
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class InputSection;
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class OutputSegment;
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// Output sections represent the finalized sections present within the final
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// linked executable. They can represent special sections (like the symbol
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// table), or represent coalesced sections from the various inputs given to the
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// linker with the same segment / section name.
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class OutputSection {
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public:
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enum Kind {
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MergedKind,
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SyntheticKind,
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};
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OutputSection(Kind kind, StringRef name) : name(name), sectionKind(kind) {}
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virtual ~OutputSection() = default;
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Kind kind() const { return sectionKind; }
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// These accessors will only be valid after finalizing the section.
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uint64_t getSegmentOffset() const;
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// How much space the section occupies in the address space.
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virtual size_t getSize() const = 0;
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// How much space the section occupies in the file. Most sections are copied
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// as-is so their file size is the same as their address space size.
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virtual uint64_t getFileSize() const { return getSize(); }
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// Hidden sections omit header content, but body content may still be present.
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virtual bool isHidden() const { return false; }
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// Unneeded sections are omitted entirely (header and body).
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virtual bool isNeeded() const { return true; }
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// Some sections may allow coalescing other raw input sections.
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virtual void mergeInput(InputSection *input);
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// Specifically finalizes addresses and section size, not content.
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virtual void finalize() {
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// TODO investigate refactoring synthetic section finalization logic into
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// overrides of this function.
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}
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virtual void writeTo(uint8_t *buf) const = 0;
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StringRef name;
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OutputSegment *parent = nullptr;
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uint32_t index = 0;
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uint64_t addr = 0;
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uint64_t fileOff = 0;
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uint32_t align = 1;
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uint32_t flags = 0;
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private:
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Kind sectionKind;
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};
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class OutputSectionComparator {
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public:
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OutputSectionComparator(uint32_t segmentOrder,
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const std::vector<StringRef> §Ordering)
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: segmentOrder(segmentOrder) {
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for (uint32_t j = 0, m = sectOrdering.size(); j < m; ++j)
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sectionOrdering[sectOrdering[j]] = j;
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}
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uint32_t sectionOrder(StringRef secname) {
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auto sectIt = sectionOrdering.find(secname);
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if (sectIt != sectionOrdering.end())
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return sectIt->second;
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return sectionOrdering.size();
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}
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// Sort sections within a common segment, which stores them in
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// a MapVector of section name -> section
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bool operator()(const std::pair<StringRef, OutputSection *> &a,
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const std::pair<StringRef, OutputSection *> &b) {
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return sectionOrder(a.first) < sectionOrder(b.first);
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}
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bool operator<(const OutputSectionComparator &b) {
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return segmentOrder < b.segmentOrder;
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}
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private:
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uint32_t segmentOrder;
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llvm::DenseMap<StringRef, uint32_t> sectionOrdering;
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};
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} // namespace macho
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} // namespace lld
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#endif
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