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//===----- RuntimeDyldMachOARM.h ---- MachO/ARM specific code. ----*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_RUNTIMEDYLDMACHOARM_H
#define LLVM_RUNTIMEDYLDMACHOARM_H
#include "../RuntimeDyldMachO.h"
#define DEBUG_TYPE "dyld"
namespace llvm {
class RuntimeDyldMachOARM
: public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOARM> {
public:
RuntimeDyldMachOARM(RTDyldMemoryManager *MM) : RuntimeDyldMachOCRTPBase(MM) {}
unsigned getMaxStubSize() override { return 8; }
unsigned getStubAlignment() override { return 1; }
relocation_iterator
processRelocationRef(unsigned SectionID, relocation_iterator RelI,
ObjectImage &ObjImg, ObjSectionToIDMap &ObjSectionToID,
const SymbolTableMap &Symbols, StubMap &Stubs) override {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
MachO::any_relocation_info RelInfo =
Obj.getRelocation(RelI->getRawDataRefImpl());
if (Obj.isRelocationScattered(RelInfo))
return ++++RelI;
RelocationEntry RE(getBasicRelocationEntry(SectionID, ObjImg, RelI));
RelocationValueRef Value(
getRelocationValueRef(ObjImg, RelI, RE, ObjSectionToID, Symbols));
bool IsExtern = Obj.getPlainRelocationExternal(RelInfo);
if (!IsExtern && RE.IsPCRel)
makeValueAddendPCRel(Value, ObjImg, RelI);
if ((RE.RelType & 0xf) == MachO::ARM_RELOC_BR24)
processBranchRelocation(RE, Value, Stubs);
else {
RE.Addend = Value.Addend;
if (Value.SymbolName)
addRelocationForSymbol(RE, Value.SymbolName);
else
addRelocationForSection(RE, Value.SectionID);
}
return ++RelI;
}
void resolveRelocation(const RelocationEntry &RE, uint64_t Value) {
DEBUG(dumpRelocationToResolve(RE, Value));
const SectionEntry &Section = Sections[RE.SectionID];
uint8_t *LocalAddress = Section.Address + RE.Offset;
// If the relocation is PC-relative, the value to be encoded is the
// pointer difference.
if (RE.IsPCRel) {
uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
Value -= FinalAddress;
// ARM PCRel relocations have an effective-PC offset of two instructions
// (four bytes in Thumb mode, 8 bytes in ARM mode).
// FIXME: For now, assume ARM mode.
Value -= 8;
}
switch (RE.RelType) {
default:
llvm_unreachable("Invalid relocation type!");
case MachO::ARM_RELOC_VANILLA:
writeBytesUnaligned(LocalAddress, Value, 1 << RE.Size);
break;
case MachO::ARM_RELOC_BR24: {
// Mask the value into the target address. We know instructions are
// 32-bit aligned, so we can do it all at once.
uint32_t *p = (uint32_t *)LocalAddress;
// The low two bits of the value are not encoded.
Value >>= 2;
// Mask the value to 24 bits.
uint64_t FinalValue = Value & 0xffffff;
// Check for overflow.
if (Value != FinalValue) {
Error("ARM BR24 relocation out of range.");
return;
}
// FIXME: If the destination is a Thumb function (and the instruction
// is a non-predicated BL instruction), we need to change it to a BLX
// instruction instead.
// Insert the value into the instruction.
*p = (*p & ~0xffffff) | FinalValue;
break;
}
case MachO::ARM_THUMB_RELOC_BR22:
case MachO::ARM_THUMB_32BIT_BRANCH:
case MachO::ARM_RELOC_HALF:
case MachO::ARM_RELOC_HALF_SECTDIFF:
case MachO::ARM_RELOC_PAIR:
case MachO::ARM_RELOC_SECTDIFF:
case MachO::ARM_RELOC_LOCAL_SECTDIFF:
case MachO::ARM_RELOC_PB_LA_PTR:
Error("Relocation type not implemented yet!");
return;
}
}
void finalizeSection(ObjectImage &ObjImg, unsigned SectionID,
const SectionRef &Section) {}
private:
void processBranchRelocation(const RelocationEntry &RE,
const RelocationValueRef &Value,
StubMap &Stubs) {
// This is an ARM branch relocation, need to use a stub function.
// Look up for existing stub.
SectionEntry &Section = Sections[RE.SectionID];
RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(Value);
uint8_t *Addr;
if (i != Stubs.end()) {
Addr = Section.Address + i->second;
} else {
// Create a new stub function.
Stubs[Value] = Section.StubOffset;
uint8_t *StubTargetAddr =
createStubFunction(Section.Address + Section.StubOffset);
RelocationEntry StubRE(RE.SectionID, StubTargetAddr - Section.Address,
MachO::GENERIC_RELOC_VANILLA, Value.Addend);
if (Value.SymbolName)
addRelocationForSymbol(StubRE, Value.SymbolName);
else
addRelocationForSection(StubRE, Value.SectionID);
Addr = Section.Address + Section.StubOffset;
Section.StubOffset += getMaxStubSize();
}
RelocationEntry TargetRE(Value.SectionID, RE.Offset, RE.RelType, 0,
RE.IsPCRel, RE.Size);
resolveRelocation(TargetRE, (uint64_t)Addr);
}
};
}
#undef DEBUG_TYPE
#endif // LLVM_RUNTIMEDYLDMACHOARM_H
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