1 //===-- ARMELFObjectWriter.cpp - ARM ELF Writer ---------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "MCTargetDesc/ARMFixupKinds.h"
11 #include "MCTargetDesc/ARMMCTargetDesc.h"
12 #include "llvm/BinaryFormat/ELF.h"
13 #include "llvm/MC/MCContext.h"
14 #include "llvm/MC/MCELFObjectWriter.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCFixup.h"
17 #include "llvm/MC/MCObjectWriter.h"
18 #include "llvm/MC/MCValue.h"
19 #include "llvm/Support/ErrorHandling.h"
20 #include "llvm/Support/raw_ostream.h"
27 class ARMELFObjectWriter : public MCELFObjectTargetWriter {
28 enum { DefaultEABIVersion = 0x05000000U };
30 unsigned GetRelocTypeInner(const MCValue &Target, const MCFixup &Fixup,
31 bool IsPCRel, MCContext &Ctx) const;
34 ARMELFObjectWriter(uint8_t OSABI);
36 ~ARMELFObjectWriter() override = default;
38 unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
39 const MCFixup &Fixup, bool IsPCRel) const override;
41 bool needsRelocateWithSymbol(const MCSymbol &Sym,
42 unsigned Type) const override;
45 } // end anonymous namespace
47 ARMELFObjectWriter::ARMELFObjectWriter(uint8_t OSABI)
48 : MCELFObjectTargetWriter(/*Is64Bit*/ false, OSABI,
50 /*HasRelocationAddend*/ false) {}
52 bool ARMELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
53 unsigned Type) const {
54 // FIXME: This is extremely conservative. This really needs to use a
55 // whitelist with a clear explanation for why each realocation needs to
56 // point to the symbol, not to the section.
61 case ELF::R_ARM_PREL31:
62 case ELF::R_ARM_ABS32:
67 // Need to examine the Fixup when determining whether to
68 // emit the relocation as an explicit symbol or as a section relative
70 unsigned ARMELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
73 return GetRelocTypeInner(Target, Fixup, IsPCRel, Ctx);
76 unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
79 MCContext &Ctx) const {
80 MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
83 switch ((unsigned)Fixup.getKind()) {
85 Ctx.reportFatalError(Fixup.getLoc(), "unsupported relocation on symbol");
86 return ELF::R_ARM_NONE;
90 llvm_unreachable("Unsupported Modifier");
91 case MCSymbolRefExpr::VK_None:
92 return ELF::R_ARM_REL32;
93 case MCSymbolRefExpr::VK_GOTTPOFF:
94 return ELF::R_ARM_TLS_IE32;
95 case MCSymbolRefExpr::VK_ARM_GOT_PREL:
96 return ELF::R_ARM_GOT_PREL;
97 case MCSymbolRefExpr::VK_ARM_PREL31:
98 return ELF::R_ARM_PREL31;
100 case ARM::fixup_arm_blx:
101 case ARM::fixup_arm_uncondbl:
103 case MCSymbolRefExpr::VK_PLT:
104 return ELF::R_ARM_CALL;
105 case MCSymbolRefExpr::VK_TLSCALL:
106 return ELF::R_ARM_TLS_CALL;
108 return ELF::R_ARM_CALL;
110 case ARM::fixup_arm_condbl:
111 case ARM::fixup_arm_condbranch:
112 case ARM::fixup_arm_uncondbranch:
113 return ELF::R_ARM_JUMP24;
114 case ARM::fixup_t2_condbranch:
115 return ELF::R_ARM_THM_JUMP19;
116 case ARM::fixup_t2_uncondbranch:
117 return ELF::R_ARM_THM_JUMP24;
118 case ARM::fixup_arm_movt_hi16:
119 return ELF::R_ARM_MOVT_PREL;
120 case ARM::fixup_arm_movw_lo16:
121 return ELF::R_ARM_MOVW_PREL_NC;
122 case ARM::fixup_t2_movt_hi16:
123 return ELF::R_ARM_THM_MOVT_PREL;
124 case ARM::fixup_t2_movw_lo16:
125 return ELF::R_ARM_THM_MOVW_PREL_NC;
126 case ARM::fixup_arm_thumb_br:
127 return ELF::R_ARM_THM_JUMP11;
128 case ARM::fixup_arm_thumb_bcc:
129 return ELF::R_ARM_THM_JUMP8;
130 case ARM::fixup_arm_thumb_bl:
131 case ARM::fixup_arm_thumb_blx:
133 case MCSymbolRefExpr::VK_TLSCALL:
134 return ELF::R_ARM_THM_TLS_CALL;
136 return ELF::R_ARM_THM_CALL;
140 switch ((unsigned)Fixup.getKind()) {
142 Ctx.reportFatalError(Fixup.getLoc(), "unsupported relocation on symbol");
143 return ELF::R_ARM_NONE;
147 llvm_unreachable("unsupported Modifier");
148 case MCSymbolRefExpr::VK_None:
149 return ELF::R_ARM_ABS8;
154 llvm_unreachable("unsupported modifier");
155 case MCSymbolRefExpr::VK_None:
156 return ELF::R_ARM_ABS16;
161 llvm_unreachable("Unsupported Modifier");
162 case MCSymbolRefExpr::VK_ARM_NONE:
163 return ELF::R_ARM_NONE;
164 case MCSymbolRefExpr::VK_GOT:
165 return ELF::R_ARM_GOT_BREL;
166 case MCSymbolRefExpr::VK_TLSGD:
167 return ELF::R_ARM_TLS_GD32;
168 case MCSymbolRefExpr::VK_TPOFF:
169 return ELF::R_ARM_TLS_LE32;
170 case MCSymbolRefExpr::VK_GOTTPOFF:
171 return ELF::R_ARM_TLS_IE32;
172 case MCSymbolRefExpr::VK_None:
173 return ELF::R_ARM_ABS32;
174 case MCSymbolRefExpr::VK_GOTOFF:
175 return ELF::R_ARM_GOTOFF32;
176 case MCSymbolRefExpr::VK_ARM_GOT_PREL:
177 return ELF::R_ARM_GOT_PREL;
178 case MCSymbolRefExpr::VK_ARM_TARGET1:
179 return ELF::R_ARM_TARGET1;
180 case MCSymbolRefExpr::VK_ARM_TARGET2:
181 return ELF::R_ARM_TARGET2;
182 case MCSymbolRefExpr::VK_ARM_PREL31:
183 return ELF::R_ARM_PREL31;
184 case MCSymbolRefExpr::VK_ARM_SBREL:
185 return ELF::R_ARM_SBREL32;
186 case MCSymbolRefExpr::VK_ARM_TLSLDO:
187 return ELF::R_ARM_TLS_LDO32;
188 case MCSymbolRefExpr::VK_TLSCALL:
189 return ELF::R_ARM_TLS_CALL;
190 case MCSymbolRefExpr::VK_TLSDESC:
191 return ELF::R_ARM_TLS_GOTDESC;
192 case MCSymbolRefExpr::VK_TLSLDM:
193 return ELF::R_ARM_TLS_LDM32;
194 case MCSymbolRefExpr::VK_ARM_TLSDESCSEQ:
195 return ELF::R_ARM_TLS_DESCSEQ;
197 case ARM::fixup_arm_condbranch:
198 case ARM::fixup_arm_uncondbranch:
199 return ELF::R_ARM_JUMP24;
200 case ARM::fixup_arm_movt_hi16:
203 llvm_unreachable("Unsupported Modifier");
204 case MCSymbolRefExpr::VK_None:
205 return ELF::R_ARM_MOVT_ABS;
206 case MCSymbolRefExpr::VK_ARM_SBREL:
207 return ELF::R_ARM_MOVT_BREL;
209 case ARM::fixup_arm_movw_lo16:
212 llvm_unreachable("Unsupported Modifier");
213 case MCSymbolRefExpr::VK_None:
214 return ELF::R_ARM_MOVW_ABS_NC;
215 case MCSymbolRefExpr::VK_ARM_SBREL:
216 return ELF::R_ARM_MOVW_BREL_NC;
218 case ARM::fixup_t2_movt_hi16:
221 llvm_unreachable("Unsupported Modifier");
222 case MCSymbolRefExpr::VK_None:
223 return ELF::R_ARM_THM_MOVT_ABS;
224 case MCSymbolRefExpr::VK_ARM_SBREL:
225 return ELF::R_ARM_THM_MOVT_BREL;
227 case ARM::fixup_t2_movw_lo16:
230 llvm_unreachable("Unsupported Modifier");
231 case MCSymbolRefExpr::VK_None:
232 return ELF::R_ARM_THM_MOVW_ABS_NC;
233 case MCSymbolRefExpr::VK_ARM_SBREL:
234 return ELF::R_ARM_THM_MOVW_BREL_NC;
239 std::unique_ptr<MCObjectWriter>
240 llvm::createARMELFObjectWriter(raw_pwrite_stream &OS, uint8_t OSABI,
241 bool IsLittleEndian) {
242 return createELFObjectWriter(llvm::make_unique<ARMELFObjectWriter>(OSABI), OS,