You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
112 lines
4.0 KiB
112 lines
4.0 KiB
//===-- llvm/MC/MCFixup.h - Instruction Relocation and Patching -*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_MC_MCFIXUP_H
|
|
#define LLVM_MC_MCFIXUP_H
|
|
|
|
#include "llvm/Support/DataTypes.h"
|
|
#include "llvm/Support/ErrorHandling.h"
|
|
#include "llvm/Support/SMLoc.h"
|
|
#include <cassert>
|
|
|
|
namespace llvm {
|
|
class MCExpr;
|
|
|
|
/// MCFixupKind - Extensible enumeration to represent the type of a fixup.
|
|
enum MCFixupKind {
|
|
FK_Data_1 = 0, ///< A one-byte fixup.
|
|
FK_Data_2, ///< A two-byte fixup.
|
|
FK_Data_4, ///< A four-byte fixup.
|
|
FK_Data_8, ///< A eight-byte fixup.
|
|
FK_PCRel_1, ///< A one-byte pc relative fixup.
|
|
FK_PCRel_2, ///< A two-byte pc relative fixup.
|
|
FK_PCRel_4, ///< A four-byte pc relative fixup.
|
|
FK_PCRel_8, ///< A eight-byte pc relative fixup.
|
|
FK_GPRel_1, ///< A one-byte gp relative fixup.
|
|
FK_GPRel_2, ///< A two-byte gp relative fixup.
|
|
FK_GPRel_4, ///< A four-byte gp relative fixup.
|
|
FK_GPRel_8, ///< A eight-byte gp relative fixup.
|
|
FK_SecRel_1, ///< A one-byte section relative fixup.
|
|
FK_SecRel_2, ///< A two-byte section relative fixup.
|
|
FK_SecRel_4, ///< A four-byte section relative fixup.
|
|
FK_SecRel_8, ///< A eight-byte section relative fixup.
|
|
|
|
FirstTargetFixupKind = 128,
|
|
|
|
// Limit range of target fixups, in case we want to pack more efficiently
|
|
// later.
|
|
MaxTargetFixupKind = (1 << 8)
|
|
};
|
|
|
|
/// MCFixup - Encode information on a single operation to perform on a byte
|
|
/// sequence (e.g., an encoded instruction) which requires assemble- or run-
|
|
/// time patching.
|
|
///
|
|
/// Fixups are used any time the target instruction encoder needs to represent
|
|
/// some value in an instruction which is not yet concrete. The encoder will
|
|
/// encode the instruction assuming the value is 0, and emit a fixup which
|
|
/// communicates to the assembler backend how it should rewrite the encoded
|
|
/// value.
|
|
///
|
|
/// During the process of relaxation, the assembler will apply fixups as
|
|
/// symbolic values become concrete. When relaxation is complete, any remaining
|
|
/// fixups become relocations in the object file (or errors, if the fixup cannot
|
|
/// be encoded on the target).
|
|
class MCFixup {
|
|
/// The value to put into the fixup location. The exact interpretation of the
|
|
/// expression is target dependent, usually it will be one of the operands to
|
|
/// an instruction or an assembler directive.
|
|
const MCExpr *Value;
|
|
|
|
/// The byte index of start of the relocation inside the encoded instruction.
|
|
uint32_t Offset;
|
|
|
|
/// The target dependent kind of fixup item this is. The kind is used to
|
|
/// determine how the operand value should be encoded into the instruction.
|
|
unsigned Kind;
|
|
|
|
/// The source location which gave rise to the fixup, if any.
|
|
SMLoc Loc;
|
|
public:
|
|
static MCFixup Create(uint32_t Offset, const MCExpr *Value,
|
|
MCFixupKind Kind, SMLoc Loc = SMLoc()) {
|
|
assert(unsigned(Kind) < MaxTargetFixupKind && "Kind out of range!");
|
|
MCFixup FI;
|
|
FI.Value = Value;
|
|
FI.Offset = Offset;
|
|
FI.Kind = unsigned(Kind);
|
|
FI.Loc = Loc;
|
|
return FI;
|
|
}
|
|
|
|
MCFixupKind getKind() const { return MCFixupKind(Kind); }
|
|
|
|
uint32_t getOffset() const { return Offset; }
|
|
void setOffset(uint32_t Value) { Offset = Value; }
|
|
|
|
const MCExpr *getValue() const { return Value; }
|
|
|
|
/// getKindForSize - Return the generic fixup kind for a value with the given
|
|
/// size. It is an error to pass an unsupported size.
|
|
static MCFixupKind getKindForSize(unsigned Size, bool isPCRel) {
|
|
switch (Size) {
|
|
default: llvm_unreachable("Invalid generic fixup size!");
|
|
case 1: return isPCRel ? FK_PCRel_1 : FK_Data_1;
|
|
case 2: return isPCRel ? FK_PCRel_2 : FK_Data_2;
|
|
case 4: return isPCRel ? FK_PCRel_4 : FK_Data_4;
|
|
case 8: return isPCRel ? FK_PCRel_8 : FK_Data_8;
|
|
}
|
|
}
|
|
|
|
SMLoc getLoc() const { return Loc; }
|
|
};
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|