xref: /freebsd/contrib/llvm-project/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZELFObjectWriter.cpp (revision a90b9d0159070121c221b966469c3e36d912bf82)
1 //===-- SystemZELFObjectWriter.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 
9 #include "MCTargetDesc/SystemZMCFixups.h"
10 #include "MCTargetDesc/SystemZMCTargetDesc.h"
11 #include "llvm/BinaryFormat/ELF.h"
12 #include "llvm/MC/MCContext.h"
13 #include "llvm/MC/MCELFObjectWriter.h"
14 #include "llvm/MC/MCExpr.h"
15 #include "llvm/MC/MCFixup.h"
16 #include "llvm/MC/MCObjectWriter.h"
17 #include "llvm/MC/MCValue.h"
18 #include "llvm/Support/ErrorHandling.h"
19 #include <cassert>
20 #include <cstdint>
21 #include <memory>
22 
23 using namespace llvm;
24 
25 namespace {
26 
27 class SystemZELFObjectWriter : public MCELFObjectTargetWriter {
28 public:
29   SystemZELFObjectWriter(uint8_t OSABI);
30   ~SystemZELFObjectWriter() override = default;
31 
32 protected:
33   // Override MCELFObjectTargetWriter.
34   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
35                         const MCFixup &Fixup, bool IsPCRel) const override;
36 };
37 
38 } // end anonymous namespace
39 
40 SystemZELFObjectWriter::SystemZELFObjectWriter(uint8_t OSABI)
41     : MCELFObjectTargetWriter(/*Is64Bit_=*/true, OSABI, ELF::EM_S390,
42                               /*HasRelocationAddend_=*/true) {}
43 
44 // Return the relocation type for an absolute value of MCFixupKind Kind.
45 static unsigned getAbsoluteReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
46   switch (Kind) {
47   case FK_Data_1:
48   case SystemZ::FK_390_U8Imm:
49   case SystemZ::FK_390_S8Imm:
50     return ELF::R_390_8;
51   case SystemZ::FK_390_U12Imm:
52     return ELF::R_390_12;
53   case FK_Data_2:
54   case SystemZ::FK_390_U16Imm:
55   case SystemZ::FK_390_S16Imm:
56     return ELF::R_390_16;
57   case SystemZ::FK_390_S20Imm:
58     return ELF::R_390_20;
59   case FK_Data_4:
60   case SystemZ::FK_390_U32Imm:
61   case SystemZ::FK_390_S32Imm:
62     return ELF::R_390_32;
63   case FK_Data_8:
64     return ELF::R_390_64;
65   }
66   Ctx.reportError(Loc, "Unsupported absolute address");
67   return 0;
68 }
69 
70 // Return the relocation type for a PC-relative value of MCFixupKind Kind.
71 static unsigned getPCRelReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
72   switch (Kind) {
73   case FK_Data_2:
74   case SystemZ::FK_390_U16Imm:
75   case SystemZ::FK_390_S16Imm:
76     return ELF::R_390_PC16;
77   case FK_Data_4:
78   case SystemZ::FK_390_U32Imm:
79   case SystemZ::FK_390_S32Imm:
80     return ELF::R_390_PC32;
81   case FK_Data_8:
82     return ELF::R_390_PC64;
83   case SystemZ::FK_390_PC12DBL:
84     return ELF::R_390_PC12DBL;
85   case SystemZ::FK_390_PC16DBL:
86     return ELF::R_390_PC16DBL;
87   case SystemZ::FK_390_PC24DBL:
88     return ELF::R_390_PC24DBL;
89   case SystemZ::FK_390_PC32DBL:
90     return ELF::R_390_PC32DBL;
91   }
92   Ctx.reportError(Loc, "Unsupported PC-relative address");
93   return 0;
94 }
95 
96 // Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
97 static unsigned getTLSLEReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
98   switch (Kind) {
99   case FK_Data_4: return ELF::R_390_TLS_LE32;
100   case FK_Data_8: return ELF::R_390_TLS_LE64;
101   }
102   Ctx.reportError(Loc, "Unsupported thread-local address (local-exec)");
103   return 0;
104 }
105 
106 // Return the R_390_TLS_LDO* relocation type for MCFixupKind Kind.
107 static unsigned getTLSLDOReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
108   switch (Kind) {
109   case FK_Data_4: return ELF::R_390_TLS_LDO32;
110   case FK_Data_8: return ELF::R_390_TLS_LDO64;
111   }
112   Ctx.reportError(Loc, "Unsupported thread-local address (local-dynamic)");
113   return 0;
114 }
115 
116 // Return the R_390_TLS_LDM* relocation type for MCFixupKind Kind.
117 static unsigned getTLSLDMReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
118   switch (Kind) {
119   case FK_Data_4: return ELF::R_390_TLS_LDM32;
120   case FK_Data_8: return ELF::R_390_TLS_LDM64;
121   case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_LDCALL;
122   }
123   Ctx.reportError(Loc, "Unsupported thread-local address (local-dynamic)");
124   return 0;
125 }
126 
127 // Return the R_390_TLS_GD* relocation type for MCFixupKind Kind.
128 static unsigned getTLSGDReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
129   switch (Kind) {
130   case FK_Data_4: return ELF::R_390_TLS_GD32;
131   case FK_Data_8: return ELF::R_390_TLS_GD64;
132   case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_GDCALL;
133   }
134   Ctx.reportError(Loc, "Unsupported thread-local address (general-dynamic)");
135   return 0;
136 }
137 
138 // Return the PLT relocation counterpart of MCFixupKind Kind.
139 static unsigned getPLTReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
140   switch (Kind) {
141   case SystemZ::FK_390_PC12DBL: return ELF::R_390_PLT12DBL;
142   case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
143   case SystemZ::FK_390_PC24DBL: return ELF::R_390_PLT24DBL;
144   case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
145   }
146   Ctx.reportError(Loc, "Unsupported PC-relative PLT address");
147   return 0;
148 }
149 
150 unsigned SystemZELFObjectWriter::getRelocType(MCContext &Ctx,
151                                               const MCValue &Target,
152                                               const MCFixup &Fixup,
153                                               bool IsPCRel) const {
154   SMLoc Loc = Fixup.getLoc();
155   unsigned Kind = Fixup.getKind();
156   if (Kind >= FirstLiteralRelocationKind)
157     return Kind - FirstLiteralRelocationKind;
158   MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
159   switch (Modifier) {
160   case MCSymbolRefExpr::VK_None:
161     if (IsPCRel)
162       return getPCRelReloc(Ctx, Loc, Kind);
163     return getAbsoluteReloc(Ctx, Loc, Kind);
164 
165   case MCSymbolRefExpr::VK_NTPOFF:
166     assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
167     return getTLSLEReloc(Ctx, Loc, Kind);
168 
169   case MCSymbolRefExpr::VK_INDNTPOFF:
170     if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
171       return ELF::R_390_TLS_IEENT;
172     Ctx.reportError(Loc, "Only PC-relative INDNTPOFF accesses are supported for now");
173     return 0;
174 
175   case MCSymbolRefExpr::VK_DTPOFF:
176     assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
177     return getTLSLDOReloc(Ctx, Loc, Kind);
178 
179   case MCSymbolRefExpr::VK_TLSLDM:
180     assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
181     return getTLSLDMReloc(Ctx, Loc, Kind);
182 
183   case MCSymbolRefExpr::VK_TLSGD:
184     assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
185     return getTLSGDReloc(Ctx, Loc, Kind);
186 
187   case MCSymbolRefExpr::VK_GOT:
188     if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
189       return ELF::R_390_GOTENT;
190     Ctx.reportError(Loc, "Only PC-relative GOT accesses are supported for now");
191     return 0;
192 
193   case MCSymbolRefExpr::VK_PLT:
194     assert(IsPCRel && "@PLT shouldn't be PC-relative");
195     return getPLTReloc(Ctx, Loc, Kind);
196 
197   default:
198     llvm_unreachable("Modifier not supported");
199   }
200 }
201 
202 std::unique_ptr<MCObjectTargetWriter>
203 llvm::createSystemZELFObjectWriter(uint8_t OSABI) {
204   return std::make_unique<SystemZELFObjectWriter>(OSABI);
205 }
206