Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- MCSection.h - Machine Code Sections ----------------------*- C++ -*-===//

//

// 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

//

//===----------------------------------------------------------------------===//

//

// This file declares the MCSection class.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_MC_MCSECTION_H

#define LLVM_MC_MCSECTION_H

#include "llvm/ADT/SmallVector.h"

#include "llvm/ADT/ilist.h"

#include "llvm/MC/MCFragment.h"

#include "llvm/MC/SectionKind.h"

#include "llvm/Support/Alignment.h"

#include <cassert>

#include <utility>

namespace llvm {

class MCAsmInfo;

class MCContext;

class MCExpr;

class MCSymbol;

class raw_ostream;

class Triple;

template <> struct ilist_alloc_traits<MCFragment> {

  static void deleteNode(MCFragment *V);

};

/// Instances of this class represent a uniqued identifier for a section in the

/// current translation unit.  The MCContext class uniques and creates these.

class MCSection {

public:

  static constexpr unsigned NonUniqueID = ~0U;

  enum SectionVariant {

    SV_COFF = 0,

    SV_ELF,

    SV_GOFF,

    SV_MachO,

    SV_Wasm,

    SV_XCOFF,

    SV_SPIRV,

    SV_DXContainer,

  };

  /// Express the state of bundle locked groups while emitting code.

  enum BundleLockStateType {

    NotBundleLocked,

    BundleLocked,

    BundleLockedAlignToEnd

  };

  using FragmentListType = iplist<MCFragment>;

  using const_iterator = FragmentListType::const_iterator;

  using iterator = FragmentListType::iterator;

  using const_reverse_iterator = FragmentListType::const_reverse_iterator;

  using reverse_iterator = FragmentListType::reverse_iterator;

private:

  MCSymbol *Begin;

  MCSymbol *End = nullptr;

  /// The alignment requirement of this section.

  Align Alignment;

  /// The section index in the assemblers section list.

  unsigned Ordinal = 0;

  /// The index of this section in the layout order.

  unsigned LayoutOrder;

  /// Keeping track of bundle-locked state.

  BundleLockStateType BundleLockState = NotBundleLocked;

  /// Current nesting depth of bundle_lock directives.

  unsigned BundleLockNestingDepth = 0;

  /// We've seen a bundle_lock directive but not its first instruction

  /// yet.

  bool BundleGroupBeforeFirstInst : 1;

  /// Whether this section has had instructions emitted into it.

  bool HasInstructions : 1;

  bool IsRegistered : 1;

  MCDummyFragment DummyFragment;

  FragmentListType Fragments;

  /// Mapping from subsection number to insertion point for subsection numbers

  /// below that number.

  SmallVector<std::pair<unsigned, MCFragment *>, 1> SubsectionFragmentMap;

  /// State for tracking labels that don't yet have Fragments

  struct PendingLabel {

    MCSymbol* Sym;

    unsigned Subsection;

    PendingLabel(MCSymbol* Sym, unsigned Subsection = 0)

      : Sym(Sym), Subsection(Subsection) {}

  };

  SmallVector<PendingLabel, 2> PendingLabels;

protected:

  // TODO Make Name private when possible.

  StringRef Name;

  SectionVariant Variant;

  SectionKind Kind;

  MCSection(SectionVariant V, StringRef Name, SectionKind K, MCSymbol *Begin);

  ~MCSection();

public:

  MCSection(const MCSection &) = delete;

  MCSection &operator=(const MCSection &) = delete;

  StringRef getName() const { return Name; }

  SectionKind getKind() const { return Kind; }

  SectionVariant getVariant() const { return Variant; }

  MCSymbol *getBeginSymbol() { return Begin; }

  const MCSymbol *getBeginSymbol() const {

    return const_cast<MCSection *>(this)->getBeginSymbol();

  }

  void setBeginSymbol(MCSymbol *Sym) {

    assert(!Begin);

    Begin = Sym;

  }

  MCSymbol *getEndSymbol(MCContext &Ctx);

  bool hasEnded() const;

  Align getAlign() const { return Alignment; }

  void setAlignment(Align Value) { Alignment = Value; }

  /// Makes sure that Alignment is at least MinAlignment.

  void ensureMinAlignment(Align MinAlignment) {

    if (Alignment < MinAlignment)

      Alignment = MinAlignment;

  }

  unsigned getOrdinal() const { return Ordinal; }

  void setOrdinal(unsigned Value) { Ordinal = Value; }

  unsigned getLayoutOrder() const { return LayoutOrder; }

  void setLayoutOrder(unsigned Value) { LayoutOrder = Value; }

  BundleLockStateType getBundleLockState() const { return BundleLockState; }

  void setBundleLockState(BundleLockStateType NewState);

  bool isBundleLocked() const { return BundleLockState != NotBundleLocked; }

  bool isBundleGroupBeforeFirstInst() const {

    return BundleGroupBeforeFirstInst;

  }

  void setBundleGroupBeforeFirstInst(bool IsFirst) {

    BundleGroupBeforeFirstInst = IsFirst;

  }

  bool hasInstructions() const { return HasInstructions; }

  void setHasInstructions(bool Value) { HasInstructions = Value; }

  bool isRegistered() const { return IsRegistered; }

  void setIsRegistered(bool Value) { IsRegistered = Value; }

  MCSection::FragmentListType &getFragmentList() { return Fragments; }

  const MCSection::FragmentListType &getFragmentList() const {

    return const_cast<MCSection *>(this)->getFragmentList();

  }

  /// Support for MCFragment::getNextNode().

  static FragmentListType MCSection::*getSublistAccess(MCFragment *) {

    return &MCSection::Fragments;

  }

  const MCDummyFragment &getDummyFragment() const { return DummyFragment; }

  MCDummyFragment &getDummyFragment() { return DummyFragment; }

  iterator begin() { return Fragments.begin(); }

  const_iterator begin() const { return Fragments.begin(); }

  iterator end() { return Fragments.end(); }

  const_iterator end() const { return Fragments.end(); }

  MCSection::iterator getSubsectionInsertionPoint(unsigned Subsection);

  void dump() const;

  virtual void printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,

                                    raw_ostream &OS,

                                    const MCExpr *Subsection) const = 0;

  /// Return true if a .align directive should use "optimized nops" to fill

  /// instead of 0s.

  virtual bool useCodeAlign() const = 0;

  /// Check whether this section is "virtual", that is has no actual object

  /// file contents.

  virtual bool isVirtualSection() const = 0;

  virtual StringRef getVirtualSectionKind() const;

  /// Add a pending label for the requested subsection. This label will be

  /// associated with a fragment in flushPendingLabels()

  void addPendingLabel(MCSymbol* label, unsigned Subsection = 0);

  /// Associate all pending labels in a subsection with a fragment.

  void flushPendingLabels(MCFragment *F, uint64_t FOffset = 0,

                          unsigned Subsection = 0);

  /// Associate all pending labels with empty data fragments. One fragment

  /// will be created for each subsection as necessary.

  void flushPendingLabels();

};

} // end namespace llvm

#endif // LLVM_MC_MCSECTION_H