LLVM  10.0.0svn
SystemZMCObjectWriter.cpp
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1 //===-- SystemZMCObjectWriter.cpp - SystemZ ELF writer --------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
11 #include "llvm/BinaryFormat/ELF.h"
13 #include "llvm/MC/MCExpr.h"
14 #include "llvm/MC/MCFixup.h"
15 #include "llvm/MC/MCObjectWriter.h"
16 #include "llvm/MC/MCValue.h"
18 #include <cassert>
19 #include <cstdint>
20 
21 using namespace llvm;
22 
23 namespace {
24 
25 class SystemZObjectWriter : public MCELFObjectTargetWriter {
26 public:
27  SystemZObjectWriter(uint8_t OSABI);
28  ~SystemZObjectWriter() override = default;
29 
30 protected:
31  // Override MCELFObjectTargetWriter.
32  unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
33  const MCFixup &Fixup, bool IsPCRel) const override;
34 };
35 
36 } // end anonymous namespace
37 
38 SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
39  : MCELFObjectTargetWriter(/*Is64Bit_=*/true, OSABI, ELF::EM_S390,
40  /*HasRelocationAddend_=*/ true) {}
41 
42 // Return the relocation type for an absolute value of MCFixupKind Kind.
43 static unsigned getAbsoluteReloc(unsigned Kind) {
44  switch (Kind) {
45  case FK_Data_1: return ELF::R_390_8;
46  case FK_Data_2: return ELF::R_390_16;
47  case FK_Data_4: return ELF::R_390_32;
48  case FK_Data_8: return ELF::R_390_64;
49  }
50  llvm_unreachable("Unsupported absolute address");
51 }
52 
53 // Return the relocation type for a PC-relative value of MCFixupKind Kind.
54 static unsigned getPCRelReloc(unsigned Kind) {
55  switch (Kind) {
56  case FK_Data_2: return ELF::R_390_PC16;
57  case FK_Data_4: return ELF::R_390_PC32;
58  case FK_Data_8: return ELF::R_390_PC64;
59  case SystemZ::FK_390_PC12DBL: return ELF::R_390_PC12DBL;
60  case SystemZ::FK_390_PC16DBL: return ELF::R_390_PC16DBL;
61  case SystemZ::FK_390_PC24DBL: return ELF::R_390_PC24DBL;
62  case SystemZ::FK_390_PC32DBL: return ELF::R_390_PC32DBL;
63  }
64  llvm_unreachable("Unsupported PC-relative address");
65 }
66 
67 // Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
68 static unsigned getTLSLEReloc(unsigned Kind) {
69  switch (Kind) {
70  case FK_Data_4: return ELF::R_390_TLS_LE32;
71  case FK_Data_8: return ELF::R_390_TLS_LE64;
72  }
73  llvm_unreachable("Unsupported absolute address");
74 }
75 
76 // Return the R_390_TLS_LDO* relocation type for MCFixupKind Kind.
77 static unsigned getTLSLDOReloc(unsigned Kind) {
78  switch (Kind) {
79  case FK_Data_4: return ELF::R_390_TLS_LDO32;
80  case FK_Data_8: return ELF::R_390_TLS_LDO64;
81  }
82  llvm_unreachable("Unsupported absolute address");
83 }
84 
85 // Return the R_390_TLS_LDM* relocation type for MCFixupKind Kind.
86 static unsigned getTLSLDMReloc(unsigned Kind) {
87  switch (Kind) {
88  case FK_Data_4: return ELF::R_390_TLS_LDM32;
89  case FK_Data_8: return ELF::R_390_TLS_LDM64;
90  case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_LDCALL;
91  }
92  llvm_unreachable("Unsupported absolute address");
93 }
94 
95 // Return the R_390_TLS_GD* relocation type for MCFixupKind Kind.
96 static unsigned getTLSGDReloc(unsigned Kind) {
97  switch (Kind) {
98  case FK_Data_4: return ELF::R_390_TLS_GD32;
99  case FK_Data_8: return ELF::R_390_TLS_GD64;
100  case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_GDCALL;
101  }
102  llvm_unreachable("Unsupported absolute address");
103 }
104 
105 // Return the PLT relocation counterpart of MCFixupKind Kind.
106 static unsigned getPLTReloc(unsigned Kind) {
107  switch (Kind) {
108  case SystemZ::FK_390_PC12DBL: return ELF::R_390_PLT12DBL;
109  case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
110  case SystemZ::FK_390_PC24DBL: return ELF::R_390_PLT24DBL;
111  case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
112  }
113  llvm_unreachable("Unsupported absolute address");
114 }
115 
117  const MCValue &Target,
118  const MCFixup &Fixup,
119  bool IsPCRel) const {
121  unsigned Kind = Fixup.getKind();
122  switch (Modifier) {
124  if (IsPCRel)
125  return getPCRelReloc(Kind);
126  return getAbsoluteReloc(Kind);
127 
129  assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
130  return getTLSLEReloc(Kind);
131 
133  if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
134  return ELF::R_390_TLS_IEENT;
135  llvm_unreachable("Only PC-relative INDNTPOFF accesses are supported for now");
136 
138  assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
139  return getTLSLDOReloc(Kind);
140 
142  assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
143  return getTLSLDMReloc(Kind);
144 
146  assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
147  return getTLSGDReloc(Kind);
148 
150  if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
151  return ELF::R_390_GOTENT;
152  llvm_unreachable("Only PC-relative GOT accesses are supported for now");
153 
155  assert(IsPCRel && "@PLT shouldt be PC-relative");
156  return getPLTReloc(Kind);
157 
158  default:
159  llvm_unreachable("Modifier not supported");
160  }
161 }
162 
163 std::unique_ptr<MCObjectTargetWriter>
165  return std::make_unique<SystemZObjectWriter>(OSABI);
166 }
This class represents lattice values for constants.
Definition: AllocatorList.h:23
This represents an "assembler immediate".
Definition: MCValue.h:39
block Block Frequency true
MCSymbolRefExpr::VariantKind getAccessVariant() const
Definition: MCValue.cpp:46
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:77
std::unique_ptr< MCObjectTargetWriter > createSystemZObjectWriter(uint8_t OSABI)
static unsigned getRelocType(const MCValue &Target, const MCFixupKind FixupKind, const bool IsPCRel)
Translates generic PPC fixup kind to Mach-O/PPC relocation type enum.
A four-byte fixup.
Definition: MCFixup.h:26
static unsigned getPCRelReloc(unsigned Kind)
Context object for machine code objects.
Definition: MCContext.h:65
static unsigned getTLSLEReloc(unsigned Kind)
static unsigned getPLTReloc(unsigned Kind)
static unsigned getTLSLDMReloc(unsigned Kind)
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
A one-byte fixup.
Definition: MCFixup.h:24
PowerPC TLS Dynamic Call Fixup
static unsigned getAbsoluteReloc(unsigned Kind)
Target - Wrapper for Target specific information.
A eight-byte fixup.
Definition: MCFixup.h:27
static unsigned getTLSLDOReloc(unsigned Kind)
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
A two-byte fixup.
Definition: MCFixup.h:25
MCFixupKind getKind() const
Definition: MCFixup.h:126