MCAsmBackend - Generic interface to target specific assembler backends. More...

#include <MCAsmBackend.h>

Collaboration diagram for llvm::MCAsmBackend:

Public Member Functions
virtual	~MCAsmBackend ()

virtual void	reset ()
	lifetime management More...

virtual MCObjectWriter *	createObjectWriter (raw_ostream &OS) const =0

virtual MCELFObjectTargetWriter *	createELFObjectTargetWriter () const

bool	hasReliableSymbolDifference () const

bool	hasDataInCodeSupport () const

virtual bool	doesSectionRequireSymbols (const MCSection &Section) const

virtual bool	isSectionAtomizable (const MCSection &Section) const

virtual void	applyFixup (const MCFixup &Fixup, char *Data, unsigned DataSize, uint64_t Value) const =0

virtual unsigned	getMinimumNopSize () const

virtual bool	writeNopData (uint64_t Count, MCObjectWriter *OW) const =0

virtual void	handleAssemblerFlag (MCAssemblerFlag Flag)

virtual uint32_t	generateCompactUnwindEncoding (ArrayRef< MCCFIInstruction >) const
	Generate the compact unwind encoding for the CFI instructions. More...

Target Fixup Interfaces
virtual unsigned	getNumFixupKinds () const =0
	getNumFixupKinds - Get the number of target specific fixup kinds. More...

virtual const MCFixupKindInfo &	getFixupKindInfo (MCFixupKind Kind) const
	getFixupKindInfo - Get information on a fixup kind. More...

virtual void	processFixupValue (const MCAssembler &Asm, const MCAsmLayout &Layout, const MCFixup &Fixup, const MCFragment *DF, MCValue &Target, uint64_t &Value, bool &IsResolved)

Target Relaxation Interfaces
virtual bool	mayNeedRelaxation (const MCInst &Inst) const =0

virtual bool	fixupNeedsRelaxation (const MCFixup &Fixup, uint64_t Value, const MCRelaxableFragment *DF, const MCAsmLayout &Layout) const =0

virtual void	relaxInstruction (const MCInst &Inst, MCInst &Res) const =0

Protected Member Functions
	MCAsmBackend ()

Protected Attributes
unsigned	HasReliableSymbolDifference: 1

unsigned	HasDataInCodeSupport: 1

Detailed Description

MCAsmBackend - Generic interface to target specific assembler backends.

Definition at line 34 of file MCAsmBackend.h.

Constructor & Destructor Documentation

MCAsmBackend::MCAsmBackend ( )

protected

Definition at line 15 of file MCAsmBackend.cpp.

MCAsmBackend::~MCAsmBackend ( )

virtual

Definition at line 18 of file MCAsmBackend.cpp.

Member Function Documentation

virtual void llvm::MCAsmBackend::applyFixup	(	const MCFixup &	Fixup,
		char *	Data,
		unsigned	DataSize,
		uint64_t	Value
	)		const

pure virtual

applyFixup - Apply the Value for given Fixup into the provided data fragment, at the offset specified by the fixup and following the fixup kind as appropriate.

Referenced by llvm::MCAssembler::Finish().

virtual MCELFObjectTargetWriter* llvm::MCAsmBackend::createELFObjectTargetWriter ( ) const

inlinevirtual

createELFObjectTargetWriter - Create a new ELFObjectTargetWriter to enable non-standard ELFObjectWriters.

Definition at line 56 of file MCAsmBackend.h.

References llvm_unreachable.

virtual MCObjectWriter* llvm::MCAsmBackend::createObjectWriter ( raw_ostream & OS ) const

pure virtual

createObjectWriter - Create a new MCObjectWriter instance for use by the assembler backend to emit the final object file.

virtual bool llvm::MCAsmBackend::doesSectionRequireSymbols ( const MCSection & Section ) const

inlinevirtual

doesSectionRequireSymbols - Check whether the given section requires that all symbols (even temporaries) have symbol table entries.

Definition at line 81 of file MCAsmBackend.h.

Referenced by llvm::MCAssembler::isSymbolLinkerVisible().

virtual bool llvm::MCAsmBackend::fixupNeedsRelaxation	(	const MCFixup &	Fixup,
		uint64_t	Value,
		const MCRelaxableFragment *	DF,
		const MCAsmLayout &	Layout
	)		const

pure virtual

fixupNeedsRelaxation - Target specific predicate for whether a given fixup requires the associated instruction to be relaxed.

virtual uint32_t llvm::MCAsmBackend::generateCompactUnwindEncoding ( ArrayRef< MCCFIInstruction > ) const

inlinevirtual

Generate the compact unwind encoding for the CFI instructions.

Definition at line 166 of file MCAsmBackend.h.

Referenced by llvm::MCStreamer::generateCompactUnwindEncodings().

const MCFixupKindInfo & MCAsmBackend::getFixupKindInfo ( MCFixupKind Kind ) const

virtual

getFixupKindInfo - Get information on a fixup kind.

Definition at line 21 of file MCAsmBackend.cpp.

References llvm::array_lengthof(), and llvm::MCFixupKindInfo::FKF_IsPCRel.

Referenced by llvm::MachObjectWriter::isFixupKindPCRel().

virtual unsigned llvm::MCAsmBackend::getMinimumNopSize ( ) const

inlinevirtual

getMinimumNopSize - Returns the minimum size of a nop in bytes on this target. The assembler will use this to emit excess padding in situations where the padding required for simple alignment would be less than the minimum nop size.

Definition at line 151 of file MCAsmBackend.h.

Referenced by llvm::MCAssembler::computeFragmentSize().

virtual unsigned llvm::MCAsmBackend::getNumFixupKinds ( ) const

pure virtual

getNumFixupKinds - Get the number of target specific fixup kinds.

virtual void llvm::MCAsmBackend::handleAssemblerFlag ( MCAssemblerFlag Flag )

inlinevirtual

handleAssemblerFlag - Handle any target-specific assembler flags. By default, do nothing.

Definition at line 162 of file MCAsmBackend.h.

bool llvm::MCAsmBackend::hasDataInCodeSupport ( ) const

inline

hasDataInCodeSupport - Check whether this target implements data-in-code markers. If not, data region directives will be ignored.

Definition at line 77 of file MCAsmBackend.h.

References HasDataInCodeSupport.

bool llvm::MCAsmBackend::hasReliableSymbolDifference ( ) const

inline

hasReliableSymbolDifference - Check whether this target implements accurate relocations for differences between symbols. If not, differences between symbols will always be relocatable expressions and any references to temporary symbols will be assumed to be in the same atom, unless they reside in a different section.

This should always be true (since it results in fewer relocations with no loss of functionality), but is currently supported as a way to maintain exact object compatibility with Darwin 'as' (on non-x86_64). It should eventually should be eliminated.

Definition at line 71 of file MCAsmBackend.h.

References HasReliableSymbolDifference.

Referenced by llvm::MachObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl().

virtual bool llvm::MCAsmBackend::isSectionAtomizable ( const MCSection & Section ) const

inlinevirtual

isSectionAtomizable - Check whether the given section can be split into atoms.

See Also: MCAssembler::isSymbolLinkerVisible().

Definition at line 89 of file MCAsmBackend.h.

Referenced by llvm::MCAssembler::getAtom().

virtual bool llvm::MCAsmBackend::mayNeedRelaxation ( const MCInst & Inst ) const

pure virtual

mayNeedRelaxation - Check whether the given instruction may need relaxation.

Parameters

Inst	- The instruction to test.

Referenced by llvm::MCObjectStreamer::EmitInstruction().

virtual void llvm::MCAsmBackend::processFixupValue	(	const MCAssembler &	Asm,
		const MCAsmLayout &	Layout,
		const MCFixup &	Fixup,
		const MCFragment *	DF,
		MCValue &	Target,
		uint64_t &	Value,
		bool &	IsResolved
	)

inlinevirtual

processFixupValue - Target hook to adjust the literal value of a fixup if necessary. IsResolved signals whether the caller believes a relocation is needed; the target can modify the value. The default does nothing.

Definition at line 105 of file MCAsmBackend.h.

virtual void llvm::MCAsmBackend::relaxInstruction	(	const MCInst &	Inst,
		MCInst &	Res
	)		const

pure virtual

RelaxInstruction - Relax the instruction in the given fragment to the next wider instruction.

Parameters

	Inst	The instruction to relax, which may be the same as the output.
[out]	Res	On return, the relaxed instruction.

Referenced by llvm::MCObjectStreamer::EmitInstruction().

virtual void llvm::MCAsmBackend::reset ( )

inlinevirtual

lifetime management

Definition at line 48 of file MCAsmBackend.h.

Referenced by llvm::LLVMTargetMachine::addPassesToEmitFile(), and llvm::MCAssembler::reset().

virtual bool llvm::MCAsmBackend::writeNopData	(	uint64_t	Count,
		MCObjectWriter *	OW
	)		const

pure virtual

writeNopData - Write an (optimal) nop sequence of Count bytes to the given output. If the target cannot generate such a sequence, it should return an error.