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//===- lib/MC/MCSection.cpp - Machine Code Section Representation ---------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCSection.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCFragment.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <utility>
using namespace llvm;
MCSection::MCSection(SectionVariant V, StringRef Name, SectionKind K,
MCSymbol *Begin)
: Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false),
IsRegistered(false), DummyFragment(this), Name(Name), Variant(V),
Kind(K) {}
MCSymbol *MCSection::getEndSymbol(MCContext &Ctx) {
if (!End)
End = Ctx.createTempSymbol("sec_end", true);
return End;
}
bool MCSection::hasEnded() const { return End && End->isInSection(); }
MCSection::~MCSection() = default;
void MCSection::setBundleLockState(BundleLockStateType NewState) {
if (NewState == NotBundleLocked) {
if (BundleLockNestingDepth == 0) {
report_fatal_error("Mismatched bundle_lock/unlock directives");
}
if (--BundleLockNestingDepth == 0) {
BundleLockState = NotBundleLocked;
}
return;
}
// If any of the directives is an align_to_end directive, the whole nested
// group is align_to_end. So don't downgrade from align_to_end to just locked.
if (BundleLockState != BundleLockedAlignToEnd) {
BundleLockState = NewState;
}
++BundleLockNestingDepth;
}
MCSection::iterator
MCSection::getSubsectionInsertionPoint(unsigned Subsection) {
if (Subsection == 0 && SubsectionFragmentMap.empty())
return end();
SmallVectorImpl<std::pair<unsigned, MCFragment *>>::iterator MI =
std::lower_bound(SubsectionFragmentMap.begin(),
SubsectionFragmentMap.end(),
std::make_pair(Subsection, (MCFragment *)nullptr));
bool ExactMatch = false;
if (MI != SubsectionFragmentMap.end()) {
ExactMatch = MI->first == Subsection;
if (ExactMatch)
++MI;
}
iterator IP;
if (MI == SubsectionFragmentMap.end())
IP = end();
else
IP = MI->second->getIterator();
if (!ExactMatch && Subsection != 0) {
// The GNU as documentation claims that subsections have an alignment of 4,
// although this appears not to be the case.
MCFragment *F = new MCDataFragment();
SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
getFragmentList().insert(IP, F);
F->setParent(this);
}
return IP;
}
StringRef MCSection::getVirtualSectionKind() const { return "virtual"; }
void MCSection::addPendingLabel(MCSymbol *label, unsigned Subsection) {
PendingLabels.push_back(PendingLabel(label, Subsection));
}
void MCSection::flushPendingLabels(MCFragment *F, uint64_t FOffset,
unsigned Subsection) {
if (PendingLabels.empty())
return;
// Set the fragment and fragment offset for all pending symbols in the
// specified Subsection, and remove those symbols from the pending list.
for (auto It = PendingLabels.begin(); It != PendingLabels.end(); ++It) {
PendingLabel& Label = *It;
if (Label.Subsection == Subsection) {
Label.Sym->setFragment(F);
Label.Sym->setOffset(FOffset);
PendingLabels.erase(It--);
}
}
}
void MCSection::flushPendingLabels() {
// Make sure all remaining pending labels point to data fragments, by
// creating new empty data fragments for each Subsection with labels pending.
while (!PendingLabels.empty()) {
PendingLabel& Label = PendingLabels[0];
iterator CurInsertionPoint =
this->getSubsectionInsertionPoint(Label.Subsection);
MCFragment *F = new MCDataFragment();
getFragmentList().insert(CurInsertionPoint, F);
F->setParent(this);
flushPendingLabels(F, 0, Label.Subsection);
}
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void MCSection::dump() const {
raw_ostream &OS = errs();
OS << "<MCSection";
OS << " Fragments:[\n ";
for (auto it = begin(), ie = end(); it != ie; ++it) {
if (it != begin())
OS << ",\n ";
it->dump();
}
OS << "]>";
}
#endif
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