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llvm-for-llvmta/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOARM.h

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//===----- RuntimeDyldMachOARM.h ---- MachO/ARM specific code. ----*- C++ -*-=//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOARM_H
#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOARM_H
#include "../RuntimeDyldMachO.h"
#include <string>
#define DEBUG_TYPE "dyld"
namespace llvm {
class RuntimeDyldMachOARM
: public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOARM> {
private:
typedef RuntimeDyldMachOCRTPBase<RuntimeDyldMachOARM> ParentT;
public:
typedef uint32_t TargetPtrT;
RuntimeDyldMachOARM(RuntimeDyld::MemoryManager &MM,
JITSymbolResolver &Resolver)
: RuntimeDyldMachOCRTPBase(MM, Resolver) {}
unsigned getMaxStubSize() const override { return 8; }
unsigned getStubAlignment() override { return 4; }
Expected<JITSymbolFlags> getJITSymbolFlags(const SymbolRef &SR) override {
auto Flags = RuntimeDyldImpl::getJITSymbolFlags(SR);
if (!Flags)
return Flags.takeError();
Flags->getTargetFlags() = ARMJITSymbolFlags::fromObjectSymbol(SR);
return Flags;
}
uint64_t modifyAddressBasedOnFlags(uint64_t Addr,
JITSymbolFlags Flags) const override {
if (Flags.getTargetFlags() & ARMJITSymbolFlags::Thumb)
Addr |= 0x1;
return Addr;
}
bool isAddrTargetThumb(unsigned SectionID, uint64_t Offset) {
auto TargetObjAddr = Sections[SectionID].getObjAddress() + Offset;
for (auto &KV : GlobalSymbolTable) {
auto &Entry = KV.second;
auto SymbolObjAddr =
Sections[Entry.getSectionID()].getObjAddress() + Entry.getOffset();
if (TargetObjAddr == SymbolObjAddr)
return (Entry.getFlags().getTargetFlags() & ARMJITSymbolFlags::Thumb);
}
return false;
}
Expected<int64_t> decodeAddend(const RelocationEntry &RE) const {
const SectionEntry &Section = Sections[RE.SectionID];
uint8_t *LocalAddress = Section.getAddressWithOffset(RE.Offset);
switch (RE.RelType) {
default:
return memcpyAddend(RE);
case MachO::ARM_RELOC_BR24: {
uint32_t Temp = readBytesUnaligned(LocalAddress, 4);
Temp &= 0x00ffffff; // Mask out the opcode.
// Now we've got the shifted immediate, shift by 2, sign extend and ret.
return SignExtend32<26>(Temp << 2);
}
case MachO::ARM_THUMB_RELOC_BR22: {
// This is a pair of instructions whose operands combine to provide 22
// bits of displacement:
// Encoding for high bits 1111 0XXX XXXX XXXX
// Encoding for low bits 1111 1XXX XXXX XXXX
uint16_t HighInsn = readBytesUnaligned(LocalAddress, 2);
if ((HighInsn & 0xf800) != 0xf000)
return make_error<StringError>("Unrecognized thumb branch encoding "
"(BR22 high bits)",
inconvertibleErrorCode());
uint16_t LowInsn = readBytesUnaligned(LocalAddress + 2, 2);
if ((LowInsn & 0xf800) != 0xf800)
return make_error<StringError>("Unrecognized thumb branch encoding "
"(BR22 low bits)",
inconvertibleErrorCode());
return SignExtend64<23>(((HighInsn & 0x7ff) << 12) |
((LowInsn & 0x7ff) << 1));
}
}
}
Expected<relocation_iterator>
processRelocationRef(unsigned SectionID, relocation_iterator RelI,
const ObjectFile &BaseObjT,
ObjSectionToIDMap &ObjSectionToID,
StubMap &Stubs) override {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile &>(BaseObjT);
MachO::any_relocation_info RelInfo =
Obj.getRelocation(RelI->getRawDataRefImpl());
uint32_t RelType = Obj.getAnyRelocationType(RelInfo);
// Set to true for thumb functions in this (or previous) TUs.
// Will be used to set the TargetIsThumbFunc member on the relocation entry.
bool TargetIsLocalThumbFunc = false;
if (Obj.getPlainRelocationExternal(RelInfo)) {
auto Symbol = RelI->getSymbol();
StringRef TargetName;
if (auto TargetNameOrErr = Symbol->getName())
TargetName = *TargetNameOrErr;
else
return TargetNameOrErr.takeError();
// If the target is external but the value doesn't have a name then we've
// converted the value to a section/offset pair, but we still need to set
// the IsTargetThumbFunc bit, so look the value up in the globla symbol table.
auto EntryItr = GlobalSymbolTable.find(TargetName);
if (EntryItr != GlobalSymbolTable.end()) {
TargetIsLocalThumbFunc =
EntryItr->second.getFlags().getTargetFlags() &
ARMJITSymbolFlags::Thumb;
}
}
if (Obj.isRelocationScattered(RelInfo)) {
if (RelType == MachO::ARM_RELOC_HALF_SECTDIFF)
return processHALFSECTDIFFRelocation(SectionID, RelI, Obj,
ObjSectionToID);
else if (RelType == MachO::GENERIC_RELOC_VANILLA)
return processScatteredVANILLA(SectionID, RelI, Obj, ObjSectionToID,
TargetIsLocalThumbFunc);
else
return ++RelI;
}
// Sanity check relocation type.
switch (RelType) {
UNIMPLEMENTED_RELOC(MachO::ARM_RELOC_PAIR);
UNIMPLEMENTED_RELOC(MachO::ARM_RELOC_SECTDIFF);
UNIMPLEMENTED_RELOC(MachO::ARM_RELOC_LOCAL_SECTDIFF);
UNIMPLEMENTED_RELOC(MachO::ARM_RELOC_PB_LA_PTR);
UNIMPLEMENTED_RELOC(MachO::ARM_THUMB_32BIT_BRANCH);
UNIMPLEMENTED_RELOC(MachO::ARM_RELOC_HALF);
default:
if (RelType > MachO::ARM_RELOC_HALF_SECTDIFF)
return make_error<RuntimeDyldError>(("MachO ARM relocation type " +
Twine(RelType) +
" is out of range").str());
break;
}
RelocationEntry RE(getRelocationEntry(SectionID, Obj, RelI));
if (auto AddendOrErr = decodeAddend(RE))
RE.Addend = *AddendOrErr;
else
return AddendOrErr.takeError();
RE.IsTargetThumbFunc = TargetIsLocalThumbFunc;
RelocationValueRef Value;
if (auto ValueOrErr = getRelocationValueRef(Obj, RelI, RE, ObjSectionToID))
Value = *ValueOrErr;
else
return ValueOrErr.takeError();
// If this is a branch from a thumb function (BR22) then make sure we mark
// the value as being a thumb stub: we don't want to mix it up with an ARM
// stub targeting the same function.
if (RE.RelType == MachO::ARM_THUMB_RELOC_BR22)
Value.IsStubThumb = true;
if (RE.IsPCRel)
makeValueAddendPCRel(Value, RelI,
(RE.RelType == MachO::ARM_THUMB_RELOC_BR22) ? 4 : 8);
// If this is a non-external branch target check whether Value points to a
// thumb func.
if (!Value.SymbolName && (RelType == MachO::ARM_RELOC_BR24 ||
RelType == MachO::ARM_THUMB_RELOC_BR22))
RE.IsTargetThumbFunc = isAddrTargetThumb(Value.SectionID, Value.Offset);
if (RE.RelType == MachO::ARM_RELOC_BR24 ||
RE.RelType == MachO::ARM_THUMB_RELOC_BR22)
processBranchRelocation(RE, Value, Stubs);
else {
RE.Addend = Value.Offset;
if (Value.SymbolName)
addRelocationForSymbol(RE, Value.SymbolName);
else
addRelocationForSection(RE, Value.SectionID);
}
return ++RelI;
}
void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
LLVM_DEBUG(dumpRelocationToResolve(RE, Value));
const SectionEntry &Section = Sections[RE.SectionID];
uint8_t *LocalAddress = Section.getAddressWithOffset(RE.Offset);
// If the relocation is PC-relative, the value to be encoded is the
// pointer difference.
if (RE.IsPCRel) {
uint64_t FinalAddress = Section.getLoadAddressWithOffset(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).
Value -= (RE.RelType == MachO::ARM_THUMB_RELOC_BR22) ? 4 : 8;
}
switch (RE.RelType) {
case MachO::ARM_THUMB_RELOC_BR22: {
Value += RE.Addend;
uint16_t HighInsn = readBytesUnaligned(LocalAddress, 2);
assert((HighInsn & 0xf800) == 0xf000 &&
"Unrecognized thumb branch encoding (BR22 high bits)");
HighInsn = (HighInsn & 0xf800) | ((Value >> 12) & 0x7ff);
uint16_t LowInsn = readBytesUnaligned(LocalAddress + 2, 2);
assert((LowInsn & 0xf800) == 0xf800 &&
"Unrecognized thumb branch encoding (BR22 low bits)");
LowInsn = (LowInsn & 0xf800) | ((Value >> 1) & 0x7ff);
writeBytesUnaligned(HighInsn, LocalAddress, 2);
writeBytesUnaligned(LowInsn, LocalAddress + 2, 2);
break;
}
case MachO::ARM_RELOC_VANILLA:
if (RE.IsTargetThumbFunc)
Value |= 0x01;
writeBytesUnaligned(Value + RE.Addend, LocalAddress, 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.
Value += RE.Addend;
// The low two bits of the value are not encoded.
Value >>= 2;
// Mask the value to 24 bits.
uint64_t FinalValue = Value & 0xffffff;
// 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.
uint32_t Temp = readBytesUnaligned(LocalAddress, 4);
writeBytesUnaligned((Temp & ~0xffffff) | FinalValue, LocalAddress, 4);
break;
}
case MachO::ARM_RELOC_HALF_SECTDIFF: {
uint64_t SectionABase = Sections[RE.Sections.SectionA].getLoadAddress();
uint64_t SectionBBase = Sections[RE.Sections.SectionB].getLoadAddress();
assert((Value == SectionABase || Value == SectionBBase) &&
"Unexpected HALFSECTDIFF relocation value.");
Value = SectionABase - SectionBBase + RE.Addend;
if (RE.Size & 0x1) // :upper16:
Value = (Value >> 16);
bool IsThumb = RE.Size & 0x2;
Value &= 0xffff;
uint32_t Insn = readBytesUnaligned(LocalAddress, 4);
if (IsThumb)
Insn = (Insn & 0x8f00fbf0) | ((Value & 0xf000) >> 12) |
((Value & 0x0800) >> 1) | ((Value & 0x0700) << 20) |
((Value & 0x00ff) << 16);
else
Insn = (Insn & 0xfff0f000) | ((Value & 0xf000) << 4) | (Value & 0x0fff);
writeBytesUnaligned(Insn, LocalAddress, 4);
break;
}
default:
llvm_unreachable("Invalid relocation type");
}
}
Error finalizeSection(const ObjectFile &Obj, unsigned SectionID,
const SectionRef &Section) {
StringRef Name;
if (Expected<StringRef> NameOrErr = Section.getName())
Name = *NameOrErr;
else
consumeError(NameOrErr.takeError());
if (Name == "__nl_symbol_ptr")
return populateIndirectSymbolPointersSection(cast<MachOObjectFile>(Obj),
Section, SectionID);
return Error::success();
}
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.getAddressWithOffset(i->second);
} else {
// Create a new stub function.
assert(Section.getStubOffset() % 4 == 0 && "Misaligned stub");
Stubs[Value] = Section.getStubOffset();
uint32_t StubOpcode = 0;
if (RE.RelType == MachO::ARM_RELOC_BR24)
StubOpcode = 0xe51ff004; // ldr pc, [pc, #-4]
else if (RE.RelType == MachO::ARM_THUMB_RELOC_BR22)
StubOpcode = 0xf000f8df; // ldr pc, [pc]
else
llvm_unreachable("Unrecognized relocation");
Addr = Section.getAddressWithOffset(Section.getStubOffset());
writeBytesUnaligned(StubOpcode, Addr, 4);
uint8_t *StubTargetAddr = Addr + 4;
RelocationEntry StubRE(
RE.SectionID, StubTargetAddr - Section.getAddress(),
MachO::GENERIC_RELOC_VANILLA, Value.Offset, false, 2);
StubRE.IsTargetThumbFunc = RE.IsTargetThumbFunc;
if (Value.SymbolName)
addRelocationForSymbol(StubRE, Value.SymbolName);
else
addRelocationForSection(StubRE, Value.SectionID);
Section.advanceStubOffset(getMaxStubSize());
}
RelocationEntry TargetRE(RE.SectionID, RE.Offset, RE.RelType, 0,
RE.IsPCRel, RE.Size);
resolveRelocation(TargetRE, (uint64_t)Addr);
}
Expected<relocation_iterator>
processHALFSECTDIFFRelocation(unsigned SectionID, relocation_iterator RelI,
const ObjectFile &BaseTObj,
ObjSectionToIDMap &ObjSectionToID) {
const MachOObjectFile &MachO =
static_cast<const MachOObjectFile&>(BaseTObj);
MachO::any_relocation_info RE =
MachO.getRelocation(RelI->getRawDataRefImpl());
// For a half-diff relocation the length bits actually record whether this
// is a movw/movt, and whether this is arm or thumb.
// Bit 0 indicates movw (b0 == 0) or movt (b0 == 1).
// Bit 1 indicates arm (b1 == 0) or thumb (b1 == 1).
unsigned HalfDiffKindBits = MachO.getAnyRelocationLength(RE);
bool IsThumb = HalfDiffKindBits & 0x2;
SectionEntry &Section = Sections[SectionID];
uint32_t RelocType = MachO.getAnyRelocationType(RE);
bool IsPCRel = MachO.getAnyRelocationPCRel(RE);
uint64_t Offset = RelI->getOffset();
uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
int64_t Immediate = readBytesUnaligned(LocalAddress, 4); // Copy the whole instruction out.
if (IsThumb)
Immediate = ((Immediate & 0x0000000f) << 12) |
((Immediate & 0x00000400) << 1) |
((Immediate & 0x70000000) >> 20) |
((Immediate & 0x00ff0000) >> 16);
else
Immediate = ((Immediate >> 4) & 0xf000) | (Immediate & 0xfff);
++RelI;
MachO::any_relocation_info RE2 =
MachO.getRelocation(RelI->getRawDataRefImpl());
uint32_t AddrA = MachO.getScatteredRelocationValue(RE);
section_iterator SAI = getSectionByAddress(MachO, AddrA);
assert(SAI != MachO.section_end() && "Can't find section for address A");
uint64_t SectionABase = SAI->getAddress();
uint64_t SectionAOffset = AddrA - SectionABase;
SectionRef SectionA = *SAI;
bool IsCode = SectionA.isText();
uint32_t SectionAID = ~0U;
if (auto SectionAIDOrErr =
findOrEmitSection(MachO, SectionA, IsCode, ObjSectionToID))
SectionAID = *SectionAIDOrErr;
else
return SectionAIDOrErr.takeError();
uint32_t AddrB = MachO.getScatteredRelocationValue(RE2);
section_iterator SBI = getSectionByAddress(MachO, AddrB);
assert(SBI != MachO.section_end() && "Can't find section for address B");
uint64_t SectionBBase = SBI->getAddress();
uint64_t SectionBOffset = AddrB - SectionBBase;
SectionRef SectionB = *SBI;
uint32_t SectionBID = ~0U;
if (auto SectionBIDOrErr =
findOrEmitSection(MachO, SectionB, IsCode, ObjSectionToID))
SectionBID = *SectionBIDOrErr;
else
return SectionBIDOrErr.takeError();
uint32_t OtherHalf = MachO.getAnyRelocationAddress(RE2) & 0xffff;
unsigned Shift = (HalfDiffKindBits & 0x1) ? 16 : 0;
uint32_t FullImmVal = (Immediate << Shift) | (OtherHalf << (16 - Shift));
int64_t Addend = FullImmVal - (AddrA - AddrB);
// addend = Encoded - Expected
// = Encoded - (AddrA - AddrB)
LLVM_DEBUG(dbgs() << "Found SECTDIFF: AddrA: " << AddrA
<< ", AddrB: " << AddrB << ", Addend: " << Addend
<< ", SectionA ID: " << SectionAID << ", SectionAOffset: "
<< SectionAOffset << ", SectionB ID: " << SectionBID
<< ", SectionBOffset: " << SectionBOffset << "\n");
RelocationEntry R(SectionID, Offset, RelocType, Addend, SectionAID,
SectionAOffset, SectionBID, SectionBOffset, IsPCRel,
HalfDiffKindBits);
addRelocationForSection(R, SectionAID);
return ++RelI;
}
};
}
#undef DEBUG_TYPE
#endif
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