1 //===-- SystemZMCAsmBackend.cpp - SystemZ assembler backend ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "MCTargetDesc/SystemZMCTargetDesc.h"
11 #include "MCTargetDesc/SystemZMCFixups.h"
12 #include "llvm/MC/MCAsmBackend.h"
13 #include "llvm/MC/MCELFObjectWriter.h"
14 #include "llvm/MC/MCFixupKindInfo.h"
15 #include "llvm/MC/MCInst.h"
16 #include "llvm/MC/MCObjectWriter.h"
20 // Value is a fully-resolved relocation value: Symbol + Addend [- Pivot].
21 // Return the bits that should be installed in a relocation field for
23 static uint64_t extractBitsForFixup(MCFixupKind Kind, uint64_t Value) {
24 if (Kind < FirstTargetFixupKind)
27 switch (unsigned(Kind)) {
28 case SystemZ::FK_390_PC16DBL:
29 case SystemZ::FK_390_PC32DBL:
30 case SystemZ::FK_390_PLT16DBL:
31 case SystemZ::FK_390_PLT32DBL:
32 return (int64_t)Value / 2;
35 llvm_unreachable("Unknown fixup kind!");
39 class SystemZMCAsmBackend : public MCAsmBackend {
42 SystemZMCAsmBackend(uint8_t osABI)
45 // Override MCAsmBackend
46 virtual unsigned getNumFixupKinds() const override {
47 return SystemZ::NumTargetFixupKinds;
49 virtual const MCFixupKindInfo &
50 getFixupKindInfo(MCFixupKind Kind) const override;
51 virtual void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
52 uint64_t Value) const override;
53 virtual bool mayNeedRelaxation(const MCInst &Inst) const override {
56 virtual bool fixupNeedsRelaxation(const MCFixup &Fixup,
58 const MCRelaxableFragment *Fragment,
59 const MCAsmLayout &Layout) const override {
62 virtual void relaxInstruction(const MCInst &Inst,
63 MCInst &Res) const override {
64 llvm_unreachable("SystemZ does do not have assembler relaxation");
66 virtual bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override;
67 virtual MCObjectWriter *createObjectWriter(raw_ostream &OS) const override {
68 return createSystemZObjectWriter(OS, OSABI);
71 } // end anonymous namespace
73 const MCFixupKindInfo &
74 SystemZMCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
75 const static MCFixupKindInfo Infos[SystemZ::NumTargetFixupKinds] = {
76 { "FK_390_PC16DBL", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
77 { "FK_390_PC32DBL", 0, 32, MCFixupKindInfo::FKF_IsPCRel },
78 { "FK_390_PLT16DBL", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
79 { "FK_390_PLT32DBL", 0, 32, MCFixupKindInfo::FKF_IsPCRel }
82 if (Kind < FirstTargetFixupKind)
83 return MCAsmBackend::getFixupKindInfo(Kind);
85 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
87 return Infos[Kind - FirstTargetFixupKind];
90 void SystemZMCAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
91 unsigned DataSize, uint64_t Value) const {
92 MCFixupKind Kind = Fixup.getKind();
93 unsigned Offset = Fixup.getOffset();
94 unsigned Size = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
96 assert(Offset + Size <= DataSize && "Invalid fixup offset!");
98 // Big-endian insertion of Size bytes.
99 Value = extractBitsForFixup(Kind, Value);
100 unsigned ShiftValue = (Size * 8) - 8;
101 for (unsigned I = 0; I != Size; ++I) {
102 Data[Offset + I] |= uint8_t(Value >> ShiftValue);
107 bool SystemZMCAsmBackend::writeNopData(uint64_t Count,
108 MCObjectWriter *OW) const {
109 for (uint64_t I = 0; I != Count; ++I)
114 MCAsmBackend *llvm::createSystemZMCAsmBackend(const Target &T,
115 const MCRegisterInfo &MRI,
116 StringRef TT, StringRef CPU) {
117 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS());
118 return new SystemZMCAsmBackend(OSABI);