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
16 using namespace llvm;
17
18 namespace {
19 class SystemZObjectWriter : public MCELFObjectTargetWriter {
20 public:
21 SystemZObjectWriter(uint8_t OSABI);
22
23 virtual ~SystemZObjectWriter();
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
SystemZObjectWriter(uint8_t OSABI)32 SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
33 : MCELFObjectTargetWriter(/*Is64Bit=*/true, OSABI, ELF::EM_S390,
34 /*HasRelocationAddend=*/ true) {}
35
~SystemZObjectWriter()36 SystemZObjectWriter::~SystemZObjectWriter() {
37 }
38
39 // Return the relocation type for an absolute value of MCFixupKind Kind.
getAbsoluteReloc(unsigned 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.
getPCRelReloc(unsigned 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 case SystemZ::FK_390_PLT16DBL: return ELF::R_390_PLT16DBL;
59 case SystemZ::FK_390_PLT32DBL: return ELF::R_390_PLT32DBL;
60 }
61 llvm_unreachable("Unsupported PC-relative address");
62 }
63
64 // Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
getTLSLEReloc(unsigned Kind)65 static unsigned getTLSLEReloc(unsigned Kind) {
66 switch (Kind) {
67 case FK_Data_4: return ELF::R_390_TLS_LE32;
68 case FK_Data_8: return ELF::R_390_TLS_LE64;
69 }
70 llvm_unreachable("Unsupported absolute address");
71 }
72
73 // Return the PLT relocation counterpart of MCFixupKind Kind.
getPLTReloc(unsigned Kind)74 static unsigned getPLTReloc(unsigned Kind) {
75 switch (Kind) {
76 case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
77 case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
78 }
79 llvm_unreachable("Unsupported absolute address");
80 }
81
GetRelocType(const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const82 unsigned SystemZObjectWriter::GetRelocType(const MCValue &Target,
83 const MCFixup &Fixup,
84 bool IsPCRel) const {
85 MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
86 unsigned Kind = Fixup.getKind();
87 switch (Modifier) {
88 case MCSymbolRefExpr::VK_None:
89 if (IsPCRel)
90 return getPCRelReloc(Kind);
91 return getAbsoluteReloc(Kind);
92
93 case MCSymbolRefExpr::VK_NTPOFF:
94 assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
95 return getTLSLEReloc(Kind);
96
97 case MCSymbolRefExpr::VK_GOT:
98 if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
99 return ELF::R_390_GOTENT;
100 llvm_unreachable("Only PC-relative GOT accesses are supported for now");
101
102 case MCSymbolRefExpr::VK_PLT:
103 assert(IsPCRel && "@PLT shouldt be PC-relative");
104 return getPLTReloc(Kind);
105
106 default:
107 llvm_unreachable("Modifier not supported");
108 }
109 }
110
createSystemZObjectWriter(raw_ostream & OS,uint8_t OSABI)111 MCObjectWriter *llvm::createSystemZObjectWriter(raw_ostream &OS,
112 uint8_t OSABI) {
113 MCELFObjectTargetWriter *MOTW = new SystemZObjectWriter(OSABI);
114 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false);
115 }
116