1//===-- SystemZMCObjectWriter.cpp - SystemZ ELF writer --------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "MCTargetDesc/SystemZMCTargetDesc.h"
11#include "MCTargetDesc/SystemZMCFixups.h"
12#include "llvm/MC/MCELFObjectWriter.h"
13#include "llvm/MC/MCExpr.h"
14#include "llvm/MC/MCValue.h"
15
16using namespace llvm;
17
18namespace {
19class SystemZObjectWriter : public MCELFObjectTargetWriter {
20public:
21  SystemZObjectWriter(uint8_t OSABI);
22
23  ~SystemZObjectWriter() override;
24
25protected:
26  // Override MCELFObjectTargetWriter.
27  unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
28                        bool IsPCRel) const override;
29};
30} // end anonymous namespace
31
32SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
33  : MCELFObjectTargetWriter(/*Is64Bit=*/true, OSABI, ELF::EM_S390,
34                            /*HasRelocationAddend=*/ true) {}
35
36SystemZObjectWriter::~SystemZObjectWriter() {
37}
38
39// Return the relocation type for an absolute value of MCFixupKind Kind.
40static unsigned getAbsoluteReloc(unsigned Kind) {
41  switch (Kind) {
42  case FK_Data_1: return ELF::R_390_8;
43  case FK_Data_2: return ELF::R_390_16;
44  case FK_Data_4: return ELF::R_390_32;
45  case FK_Data_8: return ELF::R_390_64;
46  }
47  llvm_unreachable("Unsupported absolute address");
48}
49
50// Return the relocation type for a PC-relative value of MCFixupKind Kind.
51static unsigned getPCRelReloc(unsigned Kind) {
52  switch (Kind) {
53  case FK_Data_2:                return ELF::R_390_PC16;
54  case FK_Data_4:                return ELF::R_390_PC32;
55  case FK_Data_8:                return ELF::R_390_PC64;
56  case SystemZ::FK_390_PC16DBL:  return ELF::R_390_PC16DBL;
57  case SystemZ::FK_390_PC32DBL:  return ELF::R_390_PC32DBL;
58  }
59  llvm_unreachable("Unsupported PC-relative address");
60}
61
62// Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
63static unsigned getTLSLEReloc(unsigned Kind) {
64  switch (Kind) {
65  case FK_Data_4: return ELF::R_390_TLS_LE32;
66  case FK_Data_8: return ELF::R_390_TLS_LE64;
67  }
68  llvm_unreachable("Unsupported absolute address");
69}
70
71// Return the R_390_TLS_LDO* relocation type for MCFixupKind Kind.
72static unsigned getTLSLDOReloc(unsigned Kind) {
73  switch (Kind) {
74  case FK_Data_4: return ELF::R_390_TLS_LDO32;
75  case FK_Data_8: return ELF::R_390_TLS_LDO64;
76  }
77  llvm_unreachable("Unsupported absolute address");
78}
79
80// Return the R_390_TLS_LDM* relocation type for MCFixupKind Kind.
81static unsigned getTLSLDMReloc(unsigned Kind) {
82  switch (Kind) {
83  case FK_Data_4: return ELF::R_390_TLS_LDM32;
84  case FK_Data_8: return ELF::R_390_TLS_LDM64;
85  case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_LDCALL;
86  }
87  llvm_unreachable("Unsupported absolute address");
88}
89
90// Return the R_390_TLS_GD* relocation type for MCFixupKind Kind.
91static unsigned getTLSGDReloc(unsigned Kind) {
92  switch (Kind) {
93  case FK_Data_4: return ELF::R_390_TLS_GD32;
94  case FK_Data_8: return ELF::R_390_TLS_GD64;
95  case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_GDCALL;
96  }
97  llvm_unreachable("Unsupported absolute address");
98}
99
100// Return the PLT relocation counterpart of MCFixupKind Kind.
101static unsigned getPLTReloc(unsigned Kind) {
102  switch (Kind) {
103  case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
104  case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
105  }
106  llvm_unreachable("Unsupported absolute address");
107}
108
109unsigned SystemZObjectWriter::GetRelocType(const MCValue &Target,
110                                           const MCFixup &Fixup,
111                                           bool IsPCRel) const {
112  MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
113  unsigned Kind = Fixup.getKind();
114  switch (Modifier) {
115  case MCSymbolRefExpr::VK_None:
116    if (IsPCRel)
117      return getPCRelReloc(Kind);
118    return getAbsoluteReloc(Kind);
119
120  case MCSymbolRefExpr::VK_NTPOFF:
121    assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
122    return getTLSLEReloc(Kind);
123
124  case MCSymbolRefExpr::VK_INDNTPOFF:
125    if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
126      return ELF::R_390_TLS_IEENT;
127    llvm_unreachable("Only PC-relative INDNTPOFF accesses are supported for now");
128
129  case MCSymbolRefExpr::VK_DTPOFF:
130    assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
131    return getTLSLDOReloc(Kind);
132
133  case MCSymbolRefExpr::VK_TLSLDM:
134    assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
135    return getTLSLDMReloc(Kind);
136
137  case MCSymbolRefExpr::VK_TLSGD:
138    assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
139    return getTLSGDReloc(Kind);
140
141  case MCSymbolRefExpr::VK_GOT:
142    if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
143      return ELF::R_390_GOTENT;
144    llvm_unreachable("Only PC-relative GOT accesses are supported for now");
145
146  case MCSymbolRefExpr::VK_PLT:
147    assert(IsPCRel && "@PLT shouldt be PC-relative");
148    return getPLTReloc(Kind);
149
150  default:
151    llvm_unreachable("Modifier not supported");
152  }
153}
154
155MCObjectWriter *llvm::createSystemZObjectWriter(raw_pwrite_stream &OS,
156                                                uint8_t OSABI) {
157  MCELFObjectTargetWriter *MOTW = new SystemZObjectWriter(OSABI);
158  return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false);
159}
160