//===- MCFragment.h - Fragment type hierarchy -------------------*- 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCFRAGMENT_H
#define LLVM_MC_MCFRAGMENT_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/ilist_node.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/SMLoc.h"
#include <cstdint>
#include <utility>
namespace llvm {
class MCSection;
class MCSubtargetInfo;
class MCSymbol;
class MCFragment : public ilist_node_with_parent<MCFragment, MCSection> {
friend class MCAsmLayout;
public:
enum FragmentType : uint8_t {
FT_Align,
FT_Data,
FT_CompactEncodedInst,
FT_Fill,
FT_Nops,
FT_Relaxable,
FT_Org,
FT_Dwarf,
FT_DwarfFrame,
FT_LEB,
FT_BoundaryAlign,
FT_SymbolId,
FT_CVInlineLines,
FT_CVDefRange,
FT_PseudoProbe,
FT_Dummy
};
private:
/// The data for the section this fragment is in.
MCSection *Parent;
/// The atom this fragment is in, as represented by its defining symbol.
const MCSymbol *Atom;
/// The offset of this fragment in its section. This is ~0 until
/// initialized.
uint64_t Offset;
/// The layout order of this fragment.
unsigned LayoutOrder;
/// The subsection this fragment belongs to. This is 0 if the fragment is not
// in any subsection.
unsigned SubsectionNumber = 0;
FragmentType Kind;
/// Whether fragment is being laid out.
bool IsBeingLaidOut;
protected:
bool HasInstructions;
MCFragment(FragmentType Kind, bool HasInstructions,
MCSection *Parent = nullptr);
public:
MCFragment() = delete;
MCFragment(const MCFragment &) = delete;
MCFragment &operator=(const MCFragment &) = delete;
/// Destroys the current fragment.
///
/// This must be used instead of delete as MCFragment is non-virtual.
/// This method will dispatch to the appropriate subclass.
void destroy();
FragmentType getKind() const { return Kind; }
MCSection *getParent() const { return Parent; }
void setParent(MCSection *Value) { Parent = Value; }
const MCSymbol *getAtom() const { return Atom; }
void setAtom(const MCSymbol *Value) { Atom = Value; }
unsigned getLayoutOrder() const { return LayoutOrder; }
void setLayoutOrder(unsigned Value) { LayoutOrder = Value; }
/// Does this fragment have instructions emitted into it? By default
/// this is false, but specific fragment types may set it to true.
bool hasInstructions() const { return HasInstructions; }
void dump() const;
void setSubsectionNumber(unsigned Value) { SubsectionNumber = Value; }
unsigned getSubsectionNumber() const { return SubsectionNumber; }
};
class MCDummyFragment : public MCFragment {
public:
explicit MCDummyFragment(MCSection *Sec) : MCFragment(FT_Dummy, false, Sec) {}
static bool classof(const MCFragment *F) { return F->getKind() == FT_Dummy; }
};
/// Interface implemented by fragments that contain encoded instructions and/or
/// data.
///
class MCEncodedFragment : public MCFragment {
/// Should this fragment be aligned to the end of a bundle?
bool AlignToBundleEnd = false;
uint8_t BundlePadding = 0;
protected:
MCEncodedFragment(MCFragment::FragmentType FType, bool HasInstructions,
MCSection *Sec)
: MCFragment(FType, HasInstructions, Sec) {}
/// The MCSubtargetInfo in effect when the instruction was encoded.
/// It must be non-null for instructions.
const MCSubtargetInfo *STI = nullptr;
public:
static bool classof(const MCFragment *F) {
MCFragment::FragmentType Kind = F->getKind();
switch (Kind) {
default:
return false;
case MCFragment::FT_Relaxable:
case MCFragment::FT_CompactEncodedInst:
case MCFragment::FT_Data:
case MCFragment::FT_Dwarf:
case MCFragment::FT_DwarfFrame:
case MCFragment::FT_PseudoProbe:
return true;
}
}
/// Should this fragment be placed at the end of an aligned bundle?
bool alignToBundleEnd() const { return AlignToBundleEnd; }
void setAlignToBundleEnd(bool V) { AlignToBundleEnd = V; }
/// Get the padding size that must be inserted before this fragment.
/// Used for bundling. By default, no padding is inserted.
/// Note that padding size is restricted to 8 bits. This is an optimization
/// to reduce the amount of space used for each fragment. In practice, larger
/// padding should never be required.
uint8_t getBundlePadding() const { return BundlePadding; }
/// Set the padding size for this fragment. By default it's a no-op,
/// and only some fragments have a meaningful implementation.
void setBundlePadding(uint8_t N) { BundlePadding = N; }
/// Retrieve the MCSubTargetInfo in effect when the instruction was encoded.
/// Guaranteed to be non-null if hasInstructions() == true
const MCSubtargetInfo *getSubtargetInfo() const { return STI; }
/// Record that the fragment contains instructions with the MCSubtargetInfo in
/// effect when the instruction was encoded.
void setHasInstructions(const MCSubtargetInfo &STI) {
HasInstructions = true;
this->STI = &STI;
}
};
/// Interface implemented by fragments that contain encoded instructions and/or
/// data.
///
template<unsigned ContentsSize>
class MCEncodedFragmentWithContents : public MCEncodedFragment {
SmallVector<char, ContentsSize> Contents;
protected:
MCEncodedFragmentWithContents(MCFragment::FragmentType FType,
bool HasInstructions,
MCSection *Sec)
: MCEncodedFragment(FType, HasInstructions, Sec) {}
public:
SmallVectorImpl<char> &getContents() { return Contents; }
const SmallVectorImpl<char> &getContents() const { return Contents; }
};
/// Interface implemented by fragments that contain encoded instructions and/or
/// data and also have fixups registered.
///
template<unsigned ContentsSize, unsigned FixupsSize>
class MCEncodedFragmentWithFixups :
public MCEncodedFragmentWithContents<ContentsSize> {
/// The list of fixups in this fragment.
SmallVector<MCFixup, FixupsSize> Fixups;
protected:
MCEncodedFragmentWithFixups(MCFragment::FragmentType FType,
bool HasInstructions,
MCSection *Sec)
: MCEncodedFragmentWithContents<ContentsSize>(FType, HasInstructions,
Sec) {}
public:
using const_fixup_iterator = SmallVectorImpl<MCFixup>::const_iterator;
using fixup_iterator = SmallVectorImpl<MCFixup>::iterator;
SmallVectorImpl<MCFixup> &getFixups() { return Fixups; }
const SmallVectorImpl<MCFixup> &getFixups() const { return Fixups; }
fixup_iterator fixup_begin() { return Fixups.begin(); }
const_fixup_iterator fixup_begin() const { return Fixups.begin(); }
fixup_iterator fixup_end() { return Fixups.end(); }
const_fixup_iterator fixup_end() const { return Fixups.end(); }
static bool classof(const MCFragment *F) {
MCFragment::FragmentType Kind = F->getKind();
return Kind == MCFragment::FT_Relaxable || Kind == MCFragment::FT_Data ||
Kind == MCFragment::FT_CVDefRange || Kind == MCFragment::FT_Dwarf ||
Kind == MCFragment::FT_DwarfFrame;
}
};
/// Fragment for data and encoded instructions.
///
class MCDataFragment : public MCEncodedFragmentWithFixups<32, 4> {
public:
MCDataFragment(MCSection *Sec = nullptr)
: MCEncodedFragmentWithFixups<32, 4>(FT_Data, false, Sec) {}
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_Data;
}
};
/// This is a compact (memory-size-wise) fragment for holding an encoded
/// instruction (non-relaxable) that has no fixups registered. When applicable,
/// it can be used instead of MCDataFragment and lead to lower memory
/// consumption.
///
class MCCompactEncodedInstFragment : public MCEncodedFragmentWithContents<4> {
public:
MCCompactEncodedInstFragment(MCSection *Sec = nullptr)
: MCEncodedFragmentWithContents(FT_CompactEncodedInst, true, Sec) {
}
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_CompactEncodedInst;
}
};
/// A relaxable fragment holds on to its MCInst, since it may need to be
/// relaxed during the assembler layout and relaxation stage.
///
class MCRelaxableFragment : public MCEncodedFragmentWithFixups<8, 1> {
/// The instruction this is a fragment for.
MCInst Inst;
/// Can we auto pad the instruction?
bool AllowAutoPadding = false;
public:
MCRelaxableFragment(const MCInst &Inst, const MCSubtargetInfo &STI,
MCSection *Sec = nullptr)
: MCEncodedFragmentWithFixups(FT_Relaxable, true, Sec),
Inst(Inst) { this->STI = &STI; }
const MCInst &getInst() const { return Inst; }
void setInst(const MCInst &Value) { Inst = Value; }
bool getAllowAutoPadding() const { return AllowAutoPadding; }
void setAllowAutoPadding(bool V) { AllowAutoPadding = V; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_Relaxable;
}
};
class MCAlignFragment : public MCFragment {
/// The alignment to ensure, in bytes.
Align Alignment;
/// Flag to indicate that (optimal) NOPs should be emitted instead
/// of using the provided value. The exact interpretation of this flag is
/// target dependent.
bool EmitNops : 1;
/// Value to use for filling padding bytes.
int64_t Value;
/// The size of the integer (in bytes) of \p Value.
unsigned ValueSize;
/// The maximum number of bytes to emit; if the alignment
/// cannot be satisfied in this width then this fragment is ignored.
unsigned MaxBytesToEmit;
/// When emitting Nops some subtargets have specific nop encodings.
const MCSubtargetInfo *STI;
public:
MCAlignFragment(Align Alignment, int64_t Value, unsigned ValueSize,
unsigned MaxBytesToEmit, MCSection *Sec = nullptr)
: MCFragment(FT_Align, false, Sec), Alignment(Alignment), EmitNops(false),
Value(Value), ValueSize(ValueSize), MaxBytesToEmit(MaxBytesToEmit) {}
Align getAlignment() const { return Alignment; }
int64_t getValue() const { return Value; }
unsigned getValueSize() const { return ValueSize; }
unsigned getMaxBytesToEmit() const { return MaxBytesToEmit; }
bool hasEmitNops() const { return EmitNops; }
void setEmitNops(bool Value, const MCSubtargetInfo *STI) {
EmitNops = Value;
this->STI = STI;
}
const MCSubtargetInfo *getSubtargetInfo() const { return STI; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_Align;
}
};
class MCFillFragment : public MCFragment {
uint8_t ValueSize;
/// Value to use for filling bytes.
uint64_t Value;
/// The number of bytes to insert.
const MCExpr &NumValues;
/// Source location of the directive that this fragment was created for.
SMLoc Loc;
public:
MCFillFragment(uint64_t Value, uint8_t VSize, const MCExpr &NumValues,
SMLoc Loc, MCSection *Sec = nullptr)
: MCFragment(FT_Fill, false, Sec), ValueSize(VSize), Value(Value),
NumValues(NumValues), Loc(Loc) {}
uint64_t getValue() const { return Value; }
uint8_t getValueSize() const { return ValueSize; }
const MCExpr &getNumValues() const { return NumValues; }
SMLoc getLoc() const { return Loc; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_Fill;
}
};
class MCNopsFragment : public MCFragment {
/// The number of bytes to insert.
int64_t Size;
/// Maximum number of bytes allowed in each NOP instruction.
int64_t ControlledNopLength;
/// Source location of the directive that this fragment was created for.
SMLoc Loc;
/// When emitting Nops some subtargets have specific nop encodings.
const MCSubtargetInfo &STI;
public:
MCNopsFragment(int64_t NumBytes, int64_t ControlledNopLength, SMLoc L,
const MCSubtargetInfo &STI, MCSection *Sec = nullptr)
: MCFragment(FT_Nops, false, Sec), Size(NumBytes),
ControlledNopLength(ControlledNopLength), Loc(L), STI(STI) {}
int64_t getNumBytes() const { return Size; }
int64_t getControlledNopLength() const { return ControlledNopLength; }
SMLoc getLoc() const { return Loc; }
const MCSubtargetInfo *getSubtargetInfo() const { return &STI; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_Nops;
}
};
class MCOrgFragment : public MCFragment {
/// Value to use for filling bytes.
int8_t Value;
/// The offset this fragment should start at.
const MCExpr *Offset;
/// Source location of the directive that this fragment was created for.
SMLoc Loc;
public:
MCOrgFragment(const MCExpr &Offset, int8_t Value, SMLoc Loc,
MCSection *Sec = nullptr)
: MCFragment(FT_Org, false, Sec), Value(Value), Offset(&Offset),
Loc(Loc) {}
const MCExpr &getOffset() const { return *Offset; }
uint8_t getValue() const { return Value; }
SMLoc getLoc() const { return Loc; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_Org;
}
};
class MCLEBFragment : public MCFragment {
/// True if this is a sleb128, false if uleb128.
bool IsSigned;
/// The value this fragment should contain.
const MCExpr *Value;
SmallString<8> Contents;
public:
MCLEBFragment(const MCExpr &Value_, bool IsSigned_, MCSection *Sec = nullptr)
: MCFragment(FT_LEB, false, Sec), IsSigned(IsSigned_), Value(&Value_) {
Contents.push_back(0);
}
const MCExpr &getValue() const { return *Value; }
bool isSigned() const { return IsSigned; }
SmallString<8> &getContents() { return Contents; }
const SmallString<8> &getContents() const { return Contents; }
/// @}
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_LEB;
}
};
class MCDwarfLineAddrFragment : public MCEncodedFragmentWithFixups<8, 1> {
/// The value of the difference between the two line numbers
/// between two .loc dwarf directives.
int64_t LineDelta;
/// The expression for the difference of the two symbols that
/// make up the address delta between two .loc dwarf directives.
const MCExpr *AddrDelta;
public:
MCDwarfLineAddrFragment(int64_t LineDelta, const MCExpr &AddrDelta,
MCSection *Sec = nullptr)
: MCEncodedFragmentWithFixups<8, 1>(FT_Dwarf, false, Sec),
LineDelta(LineDelta), AddrDelta(&AddrDelta) {}
int64_t getLineDelta() const { return LineDelta; }
const MCExpr &getAddrDelta() const { return *AddrDelta; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_Dwarf;
}
};
class MCDwarfCallFrameFragment : public MCEncodedFragmentWithFixups<8, 1> {
/// The expression for the difference of the two symbols that
/// make up the address delta between two .cfi_* dwarf directives.
const MCExpr *AddrDelta;
public:
MCDwarfCallFrameFragment(const MCExpr &AddrDelta, MCSection *Sec = nullptr)
: MCEncodedFragmentWithFixups<8, 1>(FT_DwarfFrame, false, Sec),
AddrDelta(&AddrDelta) {}
const MCExpr &getAddrDelta() const { return *AddrDelta; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_DwarfFrame;
}
};
/// Represents a symbol table index fragment.
class MCSymbolIdFragment : public MCFragment {
const MCSymbol *Sym;
public:
MCSymbolIdFragment(const MCSymbol *Sym, MCSection *Sec = nullptr)
: MCFragment(FT_SymbolId, false, Sec), Sym(Sym) {}
const MCSymbol *getSymbol() { return Sym; }
const MCSymbol *getSymbol() const { return Sym; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_SymbolId;
}
};
/// Fragment representing the binary annotations produced by the
/// .cv_inline_linetable directive.
class MCCVInlineLineTableFragment : public MCFragment {
unsigned SiteFuncId;
unsigned StartFileId;
unsigned StartLineNum;
const MCSymbol *FnStartSym;
const MCSymbol *FnEndSym;
SmallString<8> Contents;
/// CodeViewContext has the real knowledge about this format, so let it access
/// our members.
friend class CodeViewContext;
public:
MCCVInlineLineTableFragment(unsigned SiteFuncId, unsigned StartFileId,
unsigned StartLineNum, const MCSymbol *FnStartSym,
const MCSymbol *FnEndSym,
MCSection *Sec = nullptr)
: MCFragment(FT_CVInlineLines, false, Sec), SiteFuncId(SiteFuncId),
StartFileId(StartFileId), StartLineNum(StartLineNum),
FnStartSym(FnStartSym), FnEndSym(FnEndSym) {}
const MCSymbol *getFnStartSym() const { return FnStartSym; }
const MCSymbol *getFnEndSym() const { return FnEndSym; }
SmallString<8> &getContents() { return Contents; }
const SmallString<8> &getContents() const { return Contents; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_CVInlineLines;
}
};
/// Fragment representing the .cv_def_range directive.
class MCCVDefRangeFragment : public MCEncodedFragmentWithFixups<32, 4> {
SmallVector<std::pair<const MCSymbol *, const MCSymbol *>, 2> Ranges;
SmallString<32> FixedSizePortion;
/// CodeViewContext has the real knowledge about this format, so let it access
/// our members.
friend class CodeViewContext;
public:
MCCVDefRangeFragment(
ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
StringRef FixedSizePortion, MCSection *Sec = nullptr)
: MCEncodedFragmentWithFixups<32, 4>(FT_CVDefRange, false, Sec),
Ranges(Ranges.begin(), Ranges.end()),
FixedSizePortion(FixedSizePortion) {}
ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> getRanges() const {
return Ranges;
}
StringRef getFixedSizePortion() const { return FixedSizePortion.str(); }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_CVDefRange;
}
};
/// Represents required padding such that a particular other set of fragments
/// does not cross a particular power-of-two boundary. The other fragments must
/// follow this one within the same section.
class MCBoundaryAlignFragment : public MCFragment {
/// The alignment requirement of the branch to be aligned.
Align AlignBoundary;
/// The last fragment in the set of fragments to be aligned.
const MCFragment *LastFragment = nullptr;
/// The size of the fragment. The size is lazily set during relaxation, and
/// is not meaningful before that.
uint64_t Size = 0;
/// When emitting Nops some subtargets have specific nop encodings.
const MCSubtargetInfo &STI;
public:
MCBoundaryAlignFragment(Align AlignBoundary, const MCSubtargetInfo &STI,
MCSection *Sec = nullptr)
: MCFragment(FT_BoundaryAlign, false, Sec), AlignBoundary(AlignBoundary),
STI(STI) {}
uint64_t getSize() const { return Size; }
void setSize(uint64_t Value) { Size = Value; }
Align getAlignment() const { return AlignBoundary; }
void setAlignment(Align Value) { AlignBoundary = Value; }
const MCFragment *getLastFragment() const { return LastFragment; }
void setLastFragment(const MCFragment *F) {
assert(!F || getParent() == F->getParent());
LastFragment = F;
}
const MCSubtargetInfo *getSubtargetInfo() const { return &STI; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_BoundaryAlign;
}
};
class MCPseudoProbeAddrFragment : public MCEncodedFragmentWithFixups<8, 1> {
/// The expression for the difference of the two symbols that
/// make up the address delta between two .pseudoprobe directives.
const MCExpr *AddrDelta;
public:
MCPseudoProbeAddrFragment(const MCExpr *AddrDelta, MCSection *Sec = nullptr)
: MCEncodedFragmentWithFixups<8, 1>(FT_PseudoProbe, false, Sec),
AddrDelta(AddrDelta) {}
const MCExpr &getAddrDelta() const { return *AddrDelta; }
static bool classof(const MCFragment *F) {
return F->getKind() == MCFragment::FT_PseudoProbe;
}
};
} // end namespace llvm
#endif // LLVM_MC_MCFRAGMENT_H