140 lines
4.4 KiB
C++
140 lines
4.4 KiB
C++
//===- lib/MC/MCSection.cpp - Machine Code Section Representation ---------===//
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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 "llvm/MC/MCSection.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Config/llvm-config.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCFragment.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include <utility>
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using namespace llvm;
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MCSection::MCSection(SectionVariant V, StringRef Name, SectionKind K,
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MCSymbol *Begin)
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: Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false),
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IsRegistered(false), DummyFragment(this), Name(Name), Variant(V),
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Kind(K) {}
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MCSymbol *MCSection::getEndSymbol(MCContext &Ctx) {
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if (!End)
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End = Ctx.createTempSymbol("sec_end");
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return End;
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}
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bool MCSection::hasEnded() const { return End && End->isInSection(); }
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MCSection::~MCSection() = default;
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void MCSection::setBundleLockState(BundleLockStateType NewState) {
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if (NewState == NotBundleLocked) {
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if (BundleLockNestingDepth == 0) {
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report_fatal_error("Mismatched bundle_lock/unlock directives");
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}
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if (--BundleLockNestingDepth == 0) {
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BundleLockState = NotBundleLocked;
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}
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return;
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}
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// If any of the directives is an align_to_end directive, the whole nested
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// group is align_to_end. So don't downgrade from align_to_end to just locked.
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if (BundleLockState != BundleLockedAlignToEnd) {
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BundleLockState = NewState;
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}
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++BundleLockNestingDepth;
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}
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MCSection::iterator
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MCSection::getSubsectionInsertionPoint(unsigned Subsection) {
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if (Subsection == 0 && SubsectionFragmentMap.empty())
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return end();
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SmallVectorImpl<std::pair<unsigned, MCFragment *>>::iterator MI = lower_bound(
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SubsectionFragmentMap, std::make_pair(Subsection, (MCFragment *)nullptr));
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bool ExactMatch = false;
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if (MI != SubsectionFragmentMap.end()) {
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ExactMatch = MI->first == Subsection;
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if (ExactMatch)
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++MI;
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}
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iterator IP;
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if (MI == SubsectionFragmentMap.end())
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IP = end();
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else
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IP = MI->second->getIterator();
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if (!ExactMatch && Subsection != 0) {
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// The GNU as documentation claims that subsections have an alignment of 4,
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// although this appears not to be the case.
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MCFragment *F = new MCDataFragment();
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SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
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getFragmentList().insert(IP, F);
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F->setParent(this);
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F->setSubsectionNumber(Subsection);
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}
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return IP;
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}
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StringRef MCSection::getVirtualSectionKind() const { return "virtual"; }
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void MCSection::addPendingLabel(MCSymbol *label, unsigned Subsection) {
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PendingLabels.push_back(PendingLabel(label, Subsection));
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}
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void MCSection::flushPendingLabels(MCFragment *F, uint64_t FOffset,
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unsigned Subsection) {
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if (PendingLabels.empty())
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return;
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// Set the fragment and fragment offset for all pending symbols in the
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// specified Subsection, and remove those symbols from the pending list.
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for (auto It = PendingLabels.begin(); It != PendingLabels.end(); ++It) {
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PendingLabel& Label = *It;
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if (Label.Subsection == Subsection) {
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Label.Sym->setFragment(F);
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Label.Sym->setOffset(FOffset);
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PendingLabels.erase(It--);
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}
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}
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}
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void MCSection::flushPendingLabels() {
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// Make sure all remaining pending labels point to data fragments, by
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// creating new empty data fragments for each Subsection with labels pending.
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while (!PendingLabels.empty()) {
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PendingLabel& Label = PendingLabels[0];
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iterator CurInsertionPoint =
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this->getSubsectionInsertionPoint(Label.Subsection);
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MCFragment *F = new MCDataFragment();
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getFragmentList().insert(CurInsertionPoint, F);
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F->setParent(this);
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flushPendingLabels(F, 0, Label.Subsection);
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}
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}
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#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
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LLVM_DUMP_METHOD void MCSection::dump() const {
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raw_ostream &OS = errs();
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OS << "<MCSection";
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OS << " Fragments:[\n ";
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for (auto it = begin(), ie = end(); it != ie; ++it) {
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if (it != begin())
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OS << ",\n ";
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it->dump();
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}
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OS << "]>";
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}
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#endif
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