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Lang Hames 9a3ce89b6d [ExecutionEngine][MCJIT][Orc] Replace RuntimeDyld::SymbolInfo with JITSymbol.
This patch replaces RuntimeDyld::SymbolInfo with JITSymbol: A symbol class
that is capable of lazy materialization (i.e. the symbol definition needn't be
emitted until the address is requested). This can be used to support common
and weak symbols in the JIT (though this is not implemented in this patch).

For consistency, RuntimeDyld::SymbolResolver is renamed to JITSymbolResolver.

For space efficiency a new class, JITEvaluatedSymbol, is introduced that
behaves like the old RuntimeDyld::SymbolInfo - i.e. it is just a pair of an
address and symbol flags. Instances of JITEvaluatedSymbol can be used in
symbol-tables to avoid paying the space cost of the materializer.

llvm-svn: 277386
2016-08-01 20:49:11 +00:00

302 lines
11 KiB
C++

//===----- 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_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() override { return 8; }
unsigned getStubAlignment() override { return 4; }
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);
}
}
}
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);
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);
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_RELOC_BR22);
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));
RE.Addend = decodeAddend(RE);
RelocationValueRef Value;
if (auto ValueOrErr = getRelocationValueRef(Obj, RelI, RE, ObjSectionToID))
Value = *ValueOrErr;
else
return ValueOrErr.takeError();
if (RE.IsPCRel)
makeValueAddendPCRel(Value, RelI, 8);
if ((RE.RelType & 0xf) == MachO::ARM_RELOC_BR24)
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 {
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).
// FIXME: For now, assume ARM mode.
Value -= 8;
}
switch (RE.RelType) {
case MachO::ARM_RELOC_VANILLA:
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);
Value &= 0xffff;
uint32_t Insn = readBytesUnaligned(LocalAddress, 4);
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;
Section.getName(Name);
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.
Stubs[Value] = Section.getStubOffset();
uint8_t *StubTargetAddr = createStubFunction(
Section.getAddressWithOffset(Section.getStubOffset()));
RelocationEntry StubRE(
RE.SectionID, StubTargetAddr - Section.getAddress(),
MachO::GENERIC_RELOC_VANILLA, Value.Offset, false, 2);
if (Value.SymbolName)
addRelocationForSymbol(StubRE, Value.SymbolName);
else
addRelocationForSection(StubRE, Value.SectionID);
Addr = Section.getAddressWithOffset(Section.getStubOffset());
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);
if (HalfDiffKindBits & 0x2)
llvm_unreachable("Thumb not yet supported.");
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.
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)
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);
addRelocationForSection(R, SectionBID);
return ++RelI;
}
};
}
#undef DEBUG_TYPE
#endif