+//===-- MipsASMBackend.cpp - Mips Asm Backend ----------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the MipsAsmBackend and MipsELFObjectWriter classes.
+//
+//===----------------------------------------------------------------------===//
+//
+
+#include "MipsFixupKinds.h"
#include "MCTargetDesc/MipsMCTargetDesc.h"
-#include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCELFObjectWriter.h"
-#include "llvm/MC/MCExpr.h"
-#include "llvm/MC/MCMachObjectWriter.h"
+#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCObjectWriter.h"
-#include "llvm/MC/MCSectionELF.h"
-#include "llvm/MC/MCSectionMachO.h"
-#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCSubtargetInfo.h"
-#include "llvm/Object/MachOFormat.h"
-#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
+
using namespace llvm;
-namespace {
-class MipsELFObjectWriter : public MCELFObjectTargetWriter {
-public:
- MipsELFObjectWriter(bool is64Bit, Triple::OSType OSType, uint16_t EMachine,
- bool HasRelocationAddend)
- : MCELFObjectTargetWriter(is64Bit, OSType, EMachine,
- HasRelocationAddend) {}
-};
+// Prepare value for the target space for it
+static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
+
+ // Add/subtract and shift
+ switch (Kind) {
+ default:
+ return 0;
+ case FK_GPRel_4:
+ case FK_Data_4:
+ case Mips::fixup_Mips_LO16:
+ break;
+ case Mips::fixup_Mips_PC16:
+ // So far we are only using this type for branches.
+ // For branches we start 1 instruction after the branch
+ // so the displacement will be one instruction size less.
+ Value -= 4;
+ // The displacement is then divided by 4 to give us an 18 bit
+ // address range.
+ Value >>= 2;
+ break;
+ case Mips::fixup_Mips_26:
+ // So far we are only using this type for jumps.
+ // The displacement is then divided by 4 to give us an 28 bit
+ // address range.
+ Value >>= 2;
+ break;
+ case Mips::fixup_Mips_HI16:
+ case Mips::fixup_Mips_GOT_Local:
+ // Get the higher 16-bits. Also add 1 if bit 15 is 1.
+ Value = (Value >> 16) + ((Value & 0x8000) != 0);
+ break;
+ }
+ return Value;
+}
+
+namespace {
class MipsAsmBackend : public MCAsmBackend {
+ Triple::OSType OSType;
+ bool IsLittle; // Big or little endian
+
public:
- MipsAsmBackend(const Target &T)
- : MCAsmBackend() {}
+ MipsAsmBackend(const Target &T, Triple::OSType _OSType, bool _isLittle) :
+ MCAsmBackend(), OSType(_OSType), IsLittle(_isLittle) {}
- unsigned getNumFixupKinds() const {
- return 1; //tbd
+ MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
+ return createMipsELFObjectWriter(OS, OSType, IsLittle);
}
/// ApplyFixup - Apply the \arg Value for given \arg Fixup into the provided
/// data fragment, at the offset specified by the fixup and following the
/// fixup kind as appropriate.
- void ApplyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
+ void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
uint64_t Value) const {
+ MCFixupKind Kind = Fixup.getKind();
+ Value = adjustFixupValue((unsigned)Kind, Value);
+
+ if (!Value)
+ return; // Doesn't change encoding.
+
+ // Where do we start in the object
+ unsigned Offset = Fixup.getOffset();
+ // Number of bytes we need to fixup
+ unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
+ // Used to point to big endian bytes
+ unsigned FullSize;
+
+ switch ((unsigned)Kind) {
+ case Mips::fixup_Mips_16:
+ FullSize = 2;
+ break;
+ case Mips::fixup_Mips_64:
+ FullSize = 8;
+ break;
+ default:
+ FullSize = 4;
+ break;
+ }
+
+ // Grab current value, if any, from bits.
+ uint64_t CurVal = 0;
+
+ for (unsigned i = 0; i != NumBytes; ++i) {
+ unsigned Idx = IsLittle ? i : (FullSize - 1 - i);
+ CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i*8);
+ }
+
+ uint64_t Mask = ((uint64_t)(-1) >> (64 - getFixupKindInfo(Kind).TargetSize));
+ CurVal = (CurVal & ~Mask) | ((CurVal + Value) & Mask);
+
+ // Write out the fixed up bytes back to the code/data bits.
+ for (unsigned i = 0; i != NumBytes; ++i) {
+ unsigned Idx = IsLittle ? i : (FullSize - 1 - i);
+ Data[Offset + Idx] = (uint8_t)((CurVal >> (i*8)) & 0xff);
+ }
+ }
+
+ unsigned getNumFixupKinds() const { return Mips::NumTargetFixupKinds; }
+
+ const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const {
+ const static MCFixupKindInfo Infos[Mips::NumTargetFixupKinds] = {
+ // This table *must* be in same the order of fixup_* kinds in
+ // MipsFixupKinds.h.
+ //
+ // name offset bits flags
+ { "fixup_Mips_16", 0, 16, 0 },
+ { "fixup_Mips_32", 0, 32, 0 },
+ { "fixup_Mips_REL32", 0, 32, 0 },
+ { "fixup_Mips_26", 0, 26, 0 },
+ { "fixup_Mips_HI16", 0, 16, 0 },
+ { "fixup_Mips_LO16", 0, 16, 0 },
+ { "fixup_Mips_GPREL16", 0, 16, 0 },
+ { "fixup_Mips_LITERAL", 0, 16, 0 },
+ { "fixup_Mips_GOT_Global", 0, 16, 0 },
+ { "fixup_Mips_GOT_Local", 0, 16, 0 },
+ { "fixup_Mips_PC16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
+ { "fixup_Mips_CALL16", 0, 16, 0 },
+ { "fixup_Mips_GPREL32", 0, 32, 0 },
+ { "fixup_Mips_SHIFT5", 6, 5, 0 },
+ { "fixup_Mips_SHIFT6", 6, 5, 0 },
+ { "fixup_Mips_64", 0, 64, 0 },
+ { "fixup_Mips_TLSGD", 0, 16, 0 },
+ { "fixup_Mips_GOTTPREL", 0, 16, 0 },
+ { "fixup_Mips_TPREL_HI", 0, 16, 0 },
+ { "fixup_Mips_TPREL_LO", 0, 16, 0 },
+ { "fixup_Mips_TLSLDM", 0, 16, 0 },
+ { "fixup_Mips_DTPREL_HI", 0, 16, 0 },
+ { "fixup_Mips_DTPREL_LO", 0, 16, 0 },
+ { "fixup_Mips_Branch_PCRel", 0, 16, MCFixupKindInfo::FKF_IsPCRel }
+ };
+
+ if (Kind < FirstTargetFixupKind)
+ return MCAsmBackend::getFixupKindInfo(Kind);
+
+ assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
+ "Invalid kind!");
+ return Infos[Kind - FirstTargetFixupKind];
}
/// @name Target Relaxation Interfaces
/// relaxation.
///
/// \param Inst - The instruction to test.
- bool MayNeedRelaxation(const MCInst &Inst) const {
+ bool mayNeedRelaxation(const MCInst &Inst) const {
return false;
}
- /// RelaxInstruction - Relax the instruction in the given fragment to the next
- /// wider instruction.
+ /// fixupNeedsRelaxation - Target specific predicate for whether a given
+ /// fixup requires the associated instruction to be relaxed.
+ bool fixupNeedsRelaxation(const MCFixup &Fixup,
+ uint64_t Value,
+ const MCInstFragment *DF,
+ const MCAsmLayout &Layout) const {
+ // FIXME.
+ assert(0 && "RelaxInstruction() unimplemented");
+ return false;
+ }
+
+ /// 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
- /// output.
+ /// \param Inst - The instruction to relax, which may be the same
+ /// as the output.
/// \parm Res [output] - On return, the relaxed instruction.
- void RelaxInstruction(const MCInst &Inst, MCInst &Res) const {
+ void relaxInstruction(const MCInst &Inst, MCInst &Res) const {
}
-
+
/// @}
- /// 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.
+ /// 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.
///
/// \return - True on success.
- bool WriteNopData(uint64_t Count, MCObjectWriter *OW) const {
- return false;
+ bool writeNopData(uint64_t Count, MCObjectWriter *OW) const {
+ return true;
}
};
-class MipsEB_AsmBackend : public MipsAsmBackend {
-public:
- Triple::OSType OSType;
-
- MipsEB_AsmBackend(const Target &T, Triple::OSType _OSType)
- : MipsAsmBackend(T), OSType(_OSType) {}
-
- MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
- return createELFObjectWriter(createELFObjectTargetWriter(),
- OS, /*IsLittleEndian*/ false);
- }
+} // namespace
- MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
- return new MipsELFObjectWriter(false, OSType, ELF::EM_MIPS, false);
- }
-};
-
-class MipsEL_AsmBackend : public MipsAsmBackend {
-public:
- Triple::OSType OSType;
-
- MipsEL_AsmBackend(const Target &T, Triple::OSType _OSType)
- : MipsAsmBackend(T), OSType(_OSType) {}
-
- MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
- return createELFObjectWriter(createELFObjectTargetWriter(),
- OS, /*IsLittleEndian*/ true);
- }
-
- MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
- return new MipsELFObjectWriter(false, OSType, ELF::EM_MIPS, false);
- }
-};
+// MCAsmBackend
+MCAsmBackend *llvm::createMipsAsmBackendEL(const Target &T, StringRef TT) {
+ return new MipsAsmBackend(T, Triple(TT).getOS(),
+ /*IsLittle*/true);
}
-MCAsmBackend *llvm::createMipsAsmBackend(const Target &T, StringRef TT) {
- Triple TheTriple(TT);
-
- // just return little endian for now
- //
- return new MipsEL_AsmBackend(T, Triple(TT).getOS());
+MCAsmBackend *llvm::createMipsAsmBackendEB(const Target &T, StringRef TT) {
+ return new MipsAsmBackend(T, Triple(TT).getOS(),
+ /*IsLittle*/false);
}
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