1 //===----- RuntimeDyldMachOARM.h ---- MachO/ARM specific code. ----*- C++ -*-=//
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 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOARM_H
11 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOARM_H
13 #include "../RuntimeDyldMachO.h"
15 #define DEBUG_TYPE "dyld"
19 class RuntimeDyldMachOARM
20 : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOARM> {
22 typedef RuntimeDyldMachOCRTPBase<RuntimeDyldMachOARM> ParentT;
26 typedef uint32_t TargetPtrT;
28 RuntimeDyldMachOARM(RTDyldMemoryManager *MM) : RuntimeDyldMachOCRTPBase(MM) {}
30 unsigned getMaxStubSize() override { return 8; }
32 unsigned getStubAlignment() override { return 4; }
34 int64_t decodeAddend(const RelocationEntry &RE) const {
35 const SectionEntry &Section = Sections[RE.SectionID];
36 uint8_t *LocalAddress = Section.Address + RE.Offset;
40 return memcpyAddend(RE);
41 case MachO::ARM_RELOC_BR24: {
42 uint32_t Temp = readBytesUnaligned(LocalAddress, 4);
43 Temp &= 0x00ffffff; // Mask out the opcode.
44 // Now we've got the shifted immediate, shift by 2, sign extend and ret.
45 return SignExtend32<26>(Temp << 2);
51 processRelocationRef(unsigned SectionID, relocation_iterator RelI,
52 const ObjectFile &BaseObjT,
53 ObjSectionToIDMap &ObjSectionToID,
54 StubMap &Stubs) override {
55 const MachOObjectFile &Obj =
56 static_cast<const MachOObjectFile &>(BaseObjT);
57 MachO::any_relocation_info RelInfo =
58 Obj.getRelocation(RelI->getRawDataRefImpl());
59 uint32_t RelType = Obj.getAnyRelocationType(RelInfo);
61 if (Obj.isRelocationScattered(RelInfo)) {
62 if (RelType == MachO::ARM_RELOC_HALF_SECTDIFF)
63 return processHALFSECTDIFFRelocation(SectionID, RelI, Obj,
69 RelocationEntry RE(getRelocationEntry(SectionID, Obj, RelI));
70 RE.Addend = decodeAddend(RE);
71 RelocationValueRef Value(
72 getRelocationValueRef(Obj, RelI, RE, ObjSectionToID));
75 makeValueAddendPCRel(Value, Obj, RelI, 8);
77 if ((RE.RelType & 0xf) == MachO::ARM_RELOC_BR24)
78 processBranchRelocation(RE, Value, Stubs);
80 RE.Addend = Value.Offset;
82 addRelocationForSymbol(RE, Value.SymbolName);
84 addRelocationForSection(RE, Value.SectionID);
90 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
91 DEBUG(dumpRelocationToResolve(RE, Value));
92 const SectionEntry &Section = Sections[RE.SectionID];
93 uint8_t *LocalAddress = Section.Address + RE.Offset;
95 // If the relocation is PC-relative, the value to be encoded is the
96 // pointer difference.
98 uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
99 Value -= FinalAddress;
100 // ARM PCRel relocations have an effective-PC offset of two instructions
101 // (four bytes in Thumb mode, 8 bytes in ARM mode).
102 // FIXME: For now, assume ARM mode.
106 switch (RE.RelType) {
108 llvm_unreachable("Invalid relocation type!");
109 case MachO::ARM_RELOC_VANILLA:
110 writeBytesUnaligned(Value + RE.Addend, LocalAddress, 1 << RE.Size);
112 case MachO::ARM_RELOC_BR24: {
113 // Mask the value into the target address. We know instructions are
114 // 32-bit aligned, so we can do it all at once.
116 // The low two bits of the value are not encoded.
118 // Mask the value to 24 bits.
119 uint64_t FinalValue = Value & 0xffffff;
120 // FIXME: If the destination is a Thumb function (and the instruction
121 // is a non-predicated BL instruction), we need to change it to a BLX
122 // instruction instead.
124 // Insert the value into the instruction.
125 uint32_t Temp = readBytesUnaligned(LocalAddress, 4);
126 writeBytesUnaligned((Temp & ~0xffffff) | FinalValue, LocalAddress, 4);
130 case MachO::ARM_RELOC_HALF_SECTDIFF: {
131 uint64_t SectionABase = Sections[RE.Sections.SectionA].LoadAddress;
132 uint64_t SectionBBase = Sections[RE.Sections.SectionB].LoadAddress;
133 assert((Value == SectionABase || Value == SectionBBase) &&
134 "Unexpected HALFSECTDIFF relocation value.");
135 Value = SectionABase - SectionBBase + RE.Addend;
136 if (RE.Size & 0x1) // :upper16:
137 Value = (Value >> 16);
140 uint32_t Insn = readBytesUnaligned(LocalAddress, 4);
141 Insn = (Insn & 0xfff0f000) | ((Value & 0xf000) << 4) | (Value & 0x0fff);
142 writeBytesUnaligned(Insn, LocalAddress, 4);
146 case MachO::ARM_THUMB_RELOC_BR22:
147 case MachO::ARM_THUMB_32BIT_BRANCH:
148 case MachO::ARM_RELOC_HALF:
149 case MachO::ARM_RELOC_PAIR:
150 case MachO::ARM_RELOC_SECTDIFF:
151 case MachO::ARM_RELOC_LOCAL_SECTDIFF:
152 case MachO::ARM_RELOC_PB_LA_PTR:
153 Error("Relocation type not implemented yet!");
158 void finalizeSection(const ObjectFile &Obj, unsigned SectionID,
159 const SectionRef &Section) {
161 Section.getName(Name);
163 if (Name == "__nl_symbol_ptr")
164 populateIndirectSymbolPointersSection(cast<MachOObjectFile>(Obj),
170 void processBranchRelocation(const RelocationEntry &RE,
171 const RelocationValueRef &Value,
173 // This is an ARM branch relocation, need to use a stub function.
174 // Look up for existing stub.
175 SectionEntry &Section = Sections[RE.SectionID];
176 RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(Value);
178 if (i != Stubs.end()) {
179 Addr = Section.Address + i->second;
181 // Create a new stub function.
182 Stubs[Value] = Section.StubOffset;
183 uint8_t *StubTargetAddr =
184 createStubFunction(Section.Address + Section.StubOffset);
185 RelocationEntry StubRE(RE.SectionID, StubTargetAddr - Section.Address,
186 MachO::GENERIC_RELOC_VANILLA, Value.Offset, false,
188 if (Value.SymbolName)
189 addRelocationForSymbol(StubRE, Value.SymbolName);
191 addRelocationForSection(StubRE, Value.SectionID);
192 Addr = Section.Address + Section.StubOffset;
193 Section.StubOffset += getMaxStubSize();
195 RelocationEntry TargetRE(RE.SectionID, RE.Offset, RE.RelType, 0,
196 RE.IsPCRel, RE.Size);
197 resolveRelocation(TargetRE, (uint64_t)Addr);
201 processHALFSECTDIFFRelocation(unsigned SectionID, relocation_iterator RelI,
202 const ObjectFile &BaseTObj,
203 ObjSectionToIDMap &ObjSectionToID) {
204 const MachOObjectFile &MachO =
205 static_cast<const MachOObjectFile&>(BaseTObj);
206 MachO::any_relocation_info RE =
207 MachO.getRelocation(RelI->getRawDataRefImpl());
210 // For a half-diff relocation the length bits actually record whether this
211 // is a movw/movt, and whether this is arm or thumb.
212 // Bit 0 indicates movw (b0 == 0) or movt (b0 == 1).
213 // Bit 1 indicates arm (b1 == 0) or thumb (b1 == 1).
214 unsigned HalfDiffKindBits = MachO.getAnyRelocationLength(RE);
215 if (HalfDiffKindBits & 0x2)
216 llvm_unreachable("Thumb not yet supported.");
218 SectionEntry &Section = Sections[SectionID];
219 uint32_t RelocType = MachO.getAnyRelocationType(RE);
220 bool IsPCRel = MachO.getAnyRelocationPCRel(RE);
222 RelI->getOffset(Offset);
223 uint8_t *LocalAddress = Section.Address + Offset;
224 int64_t Immediate = readBytesUnaligned(LocalAddress, 4); // Copy the whole instruction out.
225 Immediate = ((Immediate >> 4) & 0xf000) | (Immediate & 0xfff);
228 MachO::any_relocation_info RE2 =
229 MachO.getRelocation(RelI->getRawDataRefImpl());
230 uint32_t AddrA = MachO.getScatteredRelocationValue(RE);
231 section_iterator SAI = getSectionByAddress(MachO, AddrA);
232 assert(SAI != MachO.section_end() && "Can't find section for address A");
233 uint64_t SectionABase = SAI->getAddress();
234 uint64_t SectionAOffset = AddrA - SectionABase;
235 SectionRef SectionA = *SAI;
236 bool IsCode = SectionA.isText();
237 uint32_t SectionAID =
238 findOrEmitSection(MachO, SectionA, IsCode, ObjSectionToID);
240 uint32_t AddrB = MachO.getScatteredRelocationValue(RE2);
241 section_iterator SBI = getSectionByAddress(MachO, AddrB);
242 assert(SBI != MachO.section_end() && "Can't find section for address B");
243 uint64_t SectionBBase = SBI->getAddress();
244 uint64_t SectionBOffset = AddrB - SectionBBase;
245 SectionRef SectionB = *SBI;
246 uint32_t SectionBID =
247 findOrEmitSection(MachO, SectionB, IsCode, ObjSectionToID);
249 uint32_t OtherHalf = MachO.getAnyRelocationAddress(RE2) & 0xffff;
250 unsigned Shift = (HalfDiffKindBits & 0x1) ? 16 : 0;
251 uint32_t FullImmVal = (Immediate << Shift) | (OtherHalf << (16 - Shift));
252 int64_t Addend = FullImmVal - (AddrA - AddrB);
254 // addend = Encoded - Expected
255 // = Encoded - (AddrA - AddrB)
257 DEBUG(dbgs() << "Found SECTDIFF: AddrA: " << AddrA << ", AddrB: " << AddrB
258 << ", Addend: " << Addend << ", SectionA ID: " << SectionAID
259 << ", SectionAOffset: " << SectionAOffset
260 << ", SectionB ID: " << SectionBID
261 << ", SectionBOffset: " << SectionBOffset << "\n");
262 RelocationEntry R(SectionID, Offset, RelocType, Addend, SectionAID,
263 SectionAOffset, SectionBID, SectionBOffset, IsPCRel,
266 addRelocationForSection(R, SectionAID);
267 addRelocationForSection(R, SectionBID);