#ifndef LLVM_MC_MCASMBACKEND_H
#define LLVM_MC_MCASMBACKEND_H
+#include "llvm/ADT/ArrayRef.h"
#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCFixup.h"
-#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ErrorHandling.h"
class MCAsmLayout;
class MCAssembler;
class MCELFObjectTargetWriter;
-class MCFixup;
+struct MCFixupKindInfo;
class MCFragment;
class MCInst;
-class MCInstFragment;
+class MCRelaxableFragment;
class MCObjectWriter;
class MCSection;
class MCValue;
-template<typename T>
-class SmallVectorImpl;
class raw_ostream;
/// MCAsmBackend - Generic interface to target specific assembler backends.
class MCAsmBackend {
- MCAsmBackend(const MCAsmBackend &); // DO NOT IMPLEMENT
- void operator=(const MCAsmBackend &); // DO NOT IMPLEMENT
+ MCAsmBackend(const MCAsmBackend &) LLVM_DELETED_FUNCTION;
+ void operator=(const MCAsmBackend &) LLVM_DELETED_FUNCTION;
+
protected: // Can only create subclasses.
MCAsmBackend();
- unsigned HasReliableSymbolDifference : 1;
+ unsigned HasDataInCodeSupport : 1;
public:
virtual ~MCAsmBackend();
+ /// lifetime management
+ virtual void reset() {}
+
/// createObjectWriter - Create a new MCObjectWriter instance for use by the
/// assembler backend to emit the final object file.
virtual MCObjectWriter *createObjectWriter(raw_ostream &OS) const = 0;
/// createELFObjectTargetWriter - Create a new ELFObjectTargetWriter to enable
/// non-standard ELFObjectWriters.
- virtual MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
+ virtual MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
llvm_unreachable("createELFObjectTargetWriter is not supported by asm "
"backend");
}
- /// 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.
- bool hasReliableSymbolDifference() const {
- return HasReliableSymbolDifference;
- }
+ /// hasDataInCodeSupport - Check whether this target implements data-in-code
+ /// markers. If not, data region directives will be ignored.
+ bool hasDataInCodeSupport() const { return HasDataInCodeSupport; }
/// doesSectionRequireSymbols - Check whether the given section requires that
/// all symbols (even temporaries) have symbol table entries.
virtual const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const;
/// processFixupValue - Target hook to adjust the literal value of a fixup
- /// if necessary. The default does nothing.
+ /// if necessary. IsResolved signals whether the caller believes a relocation
+ /// is needed; the target can modify the value. The default does nothing.
virtual void processFixupValue(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFixup &Fixup, const MCFragment *DF,
- MCValue &Target, uint64_t &Value) {}
-
- /// @}
+ const MCValue &Target, uint64_t &Value,
+ bool &IsResolved) {}
- /// applyFixup - Apply the \arg Value for given \arg Fixup into the provided
+ /// applyFixup - Apply the \p Value for given \p Fixup into the provided
/// data fragment, at the offset specified by the fixup and following the
/// fixup kind as appropriate.
virtual void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
- uint64_t Value) const = 0;
+ uint64_t Value, bool IsPCRel) const = 0;
/// @}
/// fixupNeedsRelaxation - Target specific predicate for whether a given
/// fixup requires the associated instruction to be relaxed.
- virtual bool fixupNeedsRelaxation(const MCFixup &Fixup,
- uint64_t Value,
- const MCInstFragment *DF,
+ virtual bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
+ const MCRelaxableFragment *DF,
const MCAsmLayout &Layout) const = 0;
/// RelaxInstruction - Relax the instruction in the given fragment to the next
/// wider instruction.
///
- /// \param Inst - The instruction to relax, which may be the same as the
+ /// \param Inst The instruction to relax, which may be the same as the
/// output.
- /// \parm Res [output] - On return, the relaxed instruction.
+ /// \param [out] Res On return, the relaxed instruction.
virtual void relaxInstruction(const MCInst &Inst, MCInst &Res) const = 0;
/// @}
+ /// 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.
+ ///
+ virtual unsigned getMinimumNopSize() const { return 1; }
+
/// 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.
/// handleAssemblerFlag - Handle any target-specific assembler flags.
/// By default, do nothing.
virtual void handleAssemblerFlag(MCAssemblerFlag Flag) {}
+
+ /// \brief Generate the compact unwind encoding for the CFI instructions.
+ virtual uint32_t
+ generateCompactUnwindEncoding(ArrayRef<MCCFIInstruction>) const {
+ return 0;
+ }
};
} // End llvm namespace