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//===-- RuntimeDyldMachO.h - Run-time dynamic linker for MC-JIT ---*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// MachO support for MC-JIT runtime dynamic linker.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_RUNTIME_DYLD_MACHO_H
#define LLVM_RUNTIME_DYLD_MACHO_H
#include "ObjectImageCommon.h"
#include "RuntimeDyldImpl.h"
#include "llvm/Object/MachO.h"
#include "llvm/Support/Format.h"
#define DEBUG_TYPE "dyld"
using namespace llvm;
using namespace llvm::object;
namespace llvm {
class RuntimeDyldMachO : public RuntimeDyldImpl {
protected:
struct SectionOffsetPair {
unsigned SectionID;
uint64_t Offset;
};
struct EHFrameRelatedSections {
EHFrameRelatedSections()
: EHFrameSID(RTDYLD_INVALID_SECTION_ID),
TextSID(RTDYLD_INVALID_SECTION_ID),
ExceptTabSID(RTDYLD_INVALID_SECTION_ID) {}
EHFrameRelatedSections(SID EH, SID T, SID Ex)
: EHFrameSID(EH), TextSID(T), ExceptTabSID(Ex) {}
SID EHFrameSID;
SID TextSID;
SID ExceptTabSID;
};
// When a module is loaded we save the SectionID of the EH frame section
// in a table until we receive a request to register all unregistered
// EH frame sections with the memory manager.
SmallVector<EHFrameRelatedSections, 2> UnregisteredEHFrameSections;
RuntimeDyldMachO(RTDyldMemoryManager *mm) : RuntimeDyldImpl(mm) {}
/// Extract the addend encoded in the instruction.
int64_t decodeAddend(uint8_t *LocalAddress, unsigned NumBytes,
uint32_t RelType) const;
/// Construct a RelocationValueRef representing the relocation target.
/// For Symbols in known sections, this will return a RelocationValueRef
/// representing a (SectionID, Offset) pair.
/// For Symbols whose section is not known, this will return a
/// (SymbolName, Offset) pair, where the Offset is taken from the instruction
/// immediate (held in RE.Addend).
/// In both cases the Addend field is *NOT* fixed up to be PC-relative. That
/// should be done by the caller where appropriate by calling makePCRel on
/// the RelocationValueRef.
RelocationValueRef getRelocationValueRef(ObjectImage &ObjImg,
const relocation_iterator &RI,
const RelocationEntry &RE,
ObjSectionToIDMap &ObjSectionToID,
const SymbolTableMap &Symbols);
/// Make the RelocationValueRef addend PC-relative.
void makeValueAddendPCRel(RelocationValueRef &Value, ObjectImage &ObjImg,
const relocation_iterator &RI);
/// Dump information about the relocation entry (RE) and resolved value.
void dumpRelocationToResolve(const RelocationEntry &RE, uint64_t Value) const;
public:
/// Create an ObjectImage from the given ObjectBuffer.
static ObjectImage *createObjectImage(ObjectBuffer *InputBuffer) {
return new ObjectImageCommon(InputBuffer);
}
/// Create an ObjectImage from the given ObjectFile.
static ObjectImage *
createObjectImageFromFile(std::unique_ptr<object::ObjectFile> InputObject) {
return new ObjectImageCommon(std::move(InputObject));
}
/// Create a RuntimeDyldMachO instance for the given target architecture.
static std::unique_ptr<RuntimeDyldMachO> create(Triple::ArchType Arch,
RTDyldMemoryManager *mm);
/// Write the least significant 'Size' bytes in 'Value' out at the address
/// pointed to by Addr. Check for overflow.
bool writeBytesUnaligned(uint8_t *Addr, uint64_t Value, unsigned Size);
SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
bool isCompatibleFormat(const ObjectBuffer *Buffer) const override;
bool isCompatibleFile(const object::ObjectFile *Obj) const override;
void registerEHFrames() override;
};
/// RuntimeDyldMachOTarget - Templated base class for generic MachO linker
/// algorithms and data structures.
///
/// Concrete, target specific sub-classes can be accessed via the impl()
/// methods. (i.e. the RuntimeDyldMachO hierarchy uses the Curiously
/// Recurring Template Idiom). Concrete subclasses for each target
/// can be found in ./Targets.
template <typename Impl>
class RuntimeDyldMachOCRTPBase : public RuntimeDyldMachO {
private:
Impl &impl() { return static_cast<Impl &>(*this); }
const Impl &impl() const { return static_cast<const Impl &>(*this); }
protected:
/// Parse the given relocation, which must be a non-scattered, and
/// return a RelocationEntry representing the information. The 'Addend' field
/// will contain the unmodified instruction immediate.
RelocationEntry getBasicRelocationEntry(unsigned SectionID,
ObjectImage &ObjImg,
const relocation_iterator &RI) const {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
MachO::any_relocation_info RelInfo =
Obj.getRelocation(RI->getRawDataRefImpl());
const SectionEntry &Section = Sections[SectionID];
bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
unsigned Size = Obj.getAnyRelocationLength(RelInfo);
uint64_t Offset;
RI->getOffset(Offset);
uint8_t *LocalAddress = Section.Address + Offset;
unsigned NumBytes = 1 << Size;
uint32_t RelType = Obj.getAnyRelocationType(RelInfo);
int64_t Addend = impl().decodeAddend(LocalAddress, NumBytes, RelType);
return RelocationEntry(SectionID, Offset, RelType, Addend, IsPCRel, Size);
}
public:
RuntimeDyldMachOCRTPBase(RTDyldMemoryManager *mm) : RuntimeDyldMachO(mm) {}
void finalizeLoad(ObjectImage &ObjImg, ObjSectionToIDMap &SectionMap) {
unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
ObjSectionToIDMap::iterator i, e;
for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
const SectionRef &Section = i->first;
StringRef Name;
Section.getName(Name);
if (Name == "__eh_frame")
EHFrameSID = i->second;
else if (Name == "__text")
TextSID = i->second;
else if (Name == "__gcc_except_tab")
ExceptTabSID = i->second;
else
impl().finalizeSection(ObjImg, i->second, Section);
}
UnregisteredEHFrameSections.push_back(
EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
}
};
} // end namespace llvm
#undef DEBUG_TYPE
#endif
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