LLVM  3.7.0
SystemZMCObjectWriter.cpp
Go to the documentation of this file.
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 
13 #include "llvm/MC/MCExpr.h"
14 #include "llvm/MC/MCValue.h"
15 
16 using namespace llvm;
17 
18 namespace {
19 class SystemZObjectWriter : public MCELFObjectTargetWriter {
20 public:
21  SystemZObjectWriter(uint8_t OSABI);
22 
23  ~SystemZObjectWriter() override;
24 
25 protected:
26  // Override MCELFObjectTargetWriter.
27  unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
28  bool IsPCRel) const override;
29 };
30 } // end anonymous namespace
31 
32 SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
33  : MCELFObjectTargetWriter(/*Is64Bit=*/true, OSABI, ELF::EM_S390,
34  /*HasRelocationAddend=*/ true) {}
35 
36 SystemZObjectWriter::~SystemZObjectWriter() {
37 }
38 
39 // Return the relocation type for an absolute value of MCFixupKind Kind.
40 static 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.
51 static 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.
63 static 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.
72 static 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.
81 static 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.
91 static 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.
101 static 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 
109 unsigned SystemZObjectWriter::GetRelocType(const MCValue &Target,
110  const MCFixup &Fixup,
111  bool IsPCRel) const {
113  unsigned Kind = Fixup.getKind();
114  switch (Modifier) {
116  if (IsPCRel)
117  return getPCRelReloc(Kind);
118  return getAbsoluteReloc(Kind);
119 
121  assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
122  return getTLSLEReloc(Kind);
123 
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 
130  assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
131  return getTLSLDOReloc(Kind);
132 
134  assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
135  return getTLSLDMReloc(Kind);
136 
138  assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
139  return getTLSGDReloc(Kind);
140 
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 
147  assert(IsPCRel && "@PLT shouldt be PC-relative");
148  return getPLTReloc(Kind);
149 
150  default:
151  llvm_unreachable("Modifier not supported");
152  }
153 }
154 
156  uint8_t OSABI) {
157  MCELFObjectTargetWriter *MOTW = new SystemZObjectWriter(OSABI);
158  return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false);
159 }
This represents an "assembler immediate".
Definition: MCValue.h:44
Defines the object file and target independent interfaces used by the assembler backend to write nati...
static unsigned getTLSGDReloc(unsigned Kind)
Encode information on a single operation to perform on a byte sequence (e.g., an encoded instruction)...
Definition: MCFixup.h:62
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:98
A four-byte fixup.
Definition: MCFixup.h:26
static unsigned getPCRelReloc(unsigned Kind)
#define true
Definition: ConvertUTF.c:66
static unsigned getTLSLEReloc(unsigned Kind)
MCSymbolRefExpr::VariantKind getAccessVariant() const
Definition: MCValue.cpp:46
MCObjectWriter * createSystemZObjectWriter(raw_pwrite_stream &OS, uint8_t OSABI)
static unsigned getPLTReloc(unsigned Kind)
static unsigned getTLSLDMReloc(unsigned Kind)
MCFixupKind getKind() const
Definition: MCFixup.h:89
A one-byte fixup.
Definition: MCFixup.h:24
PowerPC TLS Dynamic Call Fixup
static unsigned getAbsoluteReloc(unsigned Kind)
Target - Wrapper for Target specific information.
MCObjectWriter * createELFObjectWriter(MCELFObjectTargetWriter *MOTW, raw_pwrite_stream &OS, bool IsLittleEndian)
Construct a new ELF writer instance.
A eight-byte fixup.
Definition: MCFixup.h:27
static unsigned getTLSLDOReloc(unsigned Kind)
An abstract base class for streams implementations that also support a pwrite operation.
Definition: raw_ostream.h:321
const ARM::ArchExtKind Kind
A two-byte fixup.
Definition: MCFixup.h:25