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llvm-for-llvmta/lib/ExecutionEngine/JITLink/EHFrameSupport.cpp

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2022-04-25 10:02:23 +02:00
//===-------- JITLink_EHFrameSupport.cpp - JITLink eh-frame utils ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "EHFrameSupportImpl.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/Config/config.h"
#include "llvm/ExecutionEngine/Orc/TargetProcess/RegisterEHFrames.h"
#include "llvm/Support/DynamicLibrary.h"
#define DEBUG_TYPE "jitlink"
namespace llvm {
namespace jitlink {
EHFrameSplitter::EHFrameSplitter(StringRef EHFrameSectionName)
: EHFrameSectionName(EHFrameSectionName) {}
Error EHFrameSplitter::operator()(LinkGraph &G) {
auto *EHFrame = G.findSectionByName(EHFrameSectionName);
if (!EHFrame) {
LLVM_DEBUG({
dbgs() << "EHFrameSplitter: No " << EHFrameSectionName
<< " section. Nothing to do\n";
});
return Error::success();
}
LLVM_DEBUG({
dbgs() << "EHFrameSplitter: Processing " << EHFrameSectionName << "...\n";
});
DenseMap<Block *, LinkGraph::SplitBlockCache> Caches;
{
// Pre-build the split caches.
for (auto *B : EHFrame->blocks())
Caches[B] = LinkGraph::SplitBlockCache::value_type();
for (auto *Sym : EHFrame->symbols())
Caches[&Sym->getBlock()]->push_back(Sym);
for (auto *B : EHFrame->blocks())
llvm::sort(*Caches[B], [](const Symbol *LHS, const Symbol *RHS) {
return LHS->getOffset() > RHS->getOffset();
});
}
// Iterate over blocks (we do this by iterating over Caches entries rather
// than EHFrame->blocks() as we will be inserting new blocks along the way,
// which would invalidate iterators in the latter sequence.
for (auto &KV : Caches) {
auto &B = *KV.first;
auto &BCache = KV.second;
if (auto Err = processBlock(G, B, BCache))
return Err;
}
return Error::success();
}
Error EHFrameSplitter::processBlock(LinkGraph &G, Block &B,
LinkGraph::SplitBlockCache &Cache) {
LLVM_DEBUG({
dbgs() << " Processing block at " << formatv("{0:x16}", B.getAddress())
<< "\n";
});
// eh-frame should not contain zero-fill blocks.
if (B.isZeroFill())
return make_error<JITLinkError>("Unexpected zero-fill block in " +
EHFrameSectionName + " section");
if (B.getSize() == 0) {
LLVM_DEBUG(dbgs() << " Block is empty. Skipping.\n");
return Error::success();
}
BinaryStreamReader BlockReader(B.getContent(), G.getEndianness());
while (true) {
uint64_t RecordStartOffset = BlockReader.getOffset();
LLVM_DEBUG({
dbgs() << " Processing CFI record at "
<< formatv("{0:x16}", B.getAddress()) << "\n";
});
uint32_t Length;
if (auto Err = BlockReader.readInteger(Length))
return Err;
if (Length != 0xffffffff) {
if (auto Err = BlockReader.skip(Length))
return Err;
} else {
uint64_t ExtendedLength;
if (auto Err = BlockReader.readInteger(ExtendedLength))
return Err;
if (auto Err = BlockReader.skip(ExtendedLength))
return Err;
}
// If this was the last block then there's nothing to split
if (BlockReader.empty()) {
LLVM_DEBUG(dbgs() << " Extracted " << B << "\n");
return Error::success();
}
uint64_t BlockSize = BlockReader.getOffset() - RecordStartOffset;
auto &NewBlock = G.splitBlock(B, BlockSize);
(void)NewBlock;
LLVM_DEBUG(dbgs() << " Extracted " << NewBlock << "\n");
}
}
EHFrameEdgeFixer::EHFrameEdgeFixer(StringRef EHFrameSectionName,
unsigned PointerSize, Edge::Kind Delta64,
Edge::Kind Delta32, Edge::Kind NegDelta32)
: EHFrameSectionName(EHFrameSectionName), PointerSize(PointerSize),
Delta64(Delta64), Delta32(Delta32), NegDelta32(NegDelta32) {}
Error EHFrameEdgeFixer::operator()(LinkGraph &G) {
auto *EHFrame = G.findSectionByName(EHFrameSectionName);
if (!EHFrame) {
LLVM_DEBUG({
dbgs() << "EHFrameEdgeFixer: No " << EHFrameSectionName
<< " section. Nothing to do\n";
});
return Error::success();
}
// Check that we support the graph's pointer size.
if (G.getPointerSize() != 4 && G.getPointerSize() != 8)
return make_error<JITLinkError>(
"EHFrameEdgeFixer only supports 32 and 64 bit targets");
LLVM_DEBUG({
dbgs() << "EHFrameEdgeFixer: Processing " << EHFrameSectionName << "...\n";
});
ParseContext PC(G);
// Build a map of all blocks and symbols in the text sections. We will use
// these for finding / building edge targets when processing FDEs.
for (auto &Sec : G.sections()) {
PC.AddrToSyms.addSymbols(Sec.symbols());
if (auto Err = PC.AddrToBlock.addBlocks(Sec.blocks(),
BlockAddressMap::includeNonNull))
return Err;
}
// Sort eh-frame blocks into address order to ensure we visit CIEs before
// their child FDEs.
std::vector<Block *> EHFrameBlocks;
for (auto *B : EHFrame->blocks())
EHFrameBlocks.push_back(B);
llvm::sort(EHFrameBlocks, [](const Block *LHS, const Block *RHS) {
return LHS->getAddress() < RHS->getAddress();
});
// Loop over the blocks in address order.
for (auto *B : EHFrameBlocks)
if (auto Err = processBlock(PC, *B))
return Err;
return Error::success();
}
Error EHFrameEdgeFixer::processBlock(ParseContext &PC, Block &B) {
LLVM_DEBUG({
dbgs() << " Processing block at " << formatv("{0:x16}", B.getAddress())
<< "\n";
});
// eh-frame should not contain zero-fill blocks.
if (B.isZeroFill())
return make_error<JITLinkError>("Unexpected zero-fill block in " +
EHFrameSectionName + " section");
if (B.getSize() == 0) {
LLVM_DEBUG(dbgs() << " Block is empty. Skipping.\n");
return Error::success();
}
// Find the offsets of any existing edges from this block.
BlockEdgeMap BlockEdges;
for (auto &E : B.edges())
if (E.isRelocation()) {
if (BlockEdges.count(E.getOffset()))
return make_error<JITLinkError>(
"Multiple relocations at offset " +
formatv("{0:x16}", E.getOffset()) + " in " + EHFrameSectionName +
" block at address " + formatv("{0:x16}", B.getAddress()));
BlockEdges[E.getOffset()] = EdgeTarget(E);
}
CIEInfosMap CIEInfos;
BinaryStreamReader BlockReader(B.getContent(), PC.G.getEndianness());
while (!BlockReader.empty()) {
size_t RecordStartOffset = BlockReader.getOffset();
LLVM_DEBUG({
dbgs() << " Processing CFI record at "
<< formatv("{0:x16}", B.getAddress() + RecordStartOffset) << "\n";
});
// Get the record length.
size_t RecordRemaining;
{
uint32_t Length;
if (auto Err = BlockReader.readInteger(Length))
return Err;
// If Length < 0xffffffff then use the regular length field, otherwise
// read the extended length field.
if (Length != 0xffffffff)
RecordRemaining = Length;
else {
uint64_t ExtendedLength;
if (auto Err = BlockReader.readInteger(ExtendedLength))
return Err;
RecordRemaining = ExtendedLength;
}
}
if (BlockReader.bytesRemaining() < RecordRemaining)
return make_error<JITLinkError>(
"Incomplete CFI record at " +
formatv("{0:x16}", B.getAddress() + RecordStartOffset));
// Read the CIE delta for this record.
uint64_t CIEDeltaFieldOffset = BlockReader.getOffset() - RecordStartOffset;
uint32_t CIEDelta;
if (auto Err = BlockReader.readInteger(CIEDelta))
return Err;
if (CIEDelta == 0) {
if (auto Err = processCIE(PC, B, RecordStartOffset,
CIEDeltaFieldOffset + RecordRemaining,
CIEDeltaFieldOffset))
return Err;
} else {
if (auto Err = processFDE(PC, B, RecordStartOffset,
CIEDeltaFieldOffset + RecordRemaining,
CIEDeltaFieldOffset, CIEDelta, BlockEdges))
return Err;
}
// Move to the next record.
BlockReader.setOffset(RecordStartOffset + CIEDeltaFieldOffset +
RecordRemaining);
}
return Error::success();
}
Error EHFrameEdgeFixer::processCIE(ParseContext &PC, Block &B,
size_t RecordOffset, size_t RecordLength,
size_t CIEDeltaFieldOffset) {
LLVM_DEBUG(dbgs() << " Record is CIE\n");
auto RecordContent = B.getContent().substr(RecordOffset, RecordLength);
BinaryStreamReader RecordReader(RecordContent, PC.G.getEndianness());
// Skip past the CIE delta field: we've already processed this far.
RecordReader.setOffset(CIEDeltaFieldOffset + 4);
auto &CIESymbol =
PC.G.addAnonymousSymbol(B, RecordOffset, RecordLength, false, false);
CIEInformation CIEInfo(CIESymbol);
uint8_t Version = 0;
if (auto Err = RecordReader.readInteger(Version))
return Err;
if (Version != 0x01)
return make_error<JITLinkError>("Bad CIE version " + Twine(Version) +
" (should be 0x01) in eh-frame");
auto AugInfo = parseAugmentationString(RecordReader);
if (!AugInfo)
return AugInfo.takeError();
// Skip the EH Data field if present.
if (AugInfo->EHDataFieldPresent)
if (auto Err = RecordReader.skip(PC.G.getPointerSize()))
return Err;
// Read and sanity check the code alignment factor.
{
uint64_t CodeAlignmentFactor = 0;
if (auto Err = RecordReader.readULEB128(CodeAlignmentFactor))
return Err;
if (CodeAlignmentFactor != 1)
return make_error<JITLinkError>("Unsupported CIE code alignment factor " +
Twine(CodeAlignmentFactor) +
" (expected 1)");
}
// Read and sanity check the data alignment factor.
{
int64_t DataAlignmentFactor = 0;
if (auto Err = RecordReader.readSLEB128(DataAlignmentFactor))
return Err;
if (DataAlignmentFactor != -8)
return make_error<JITLinkError>("Unsupported CIE data alignment factor " +
Twine(DataAlignmentFactor) +
" (expected -8)");
}
// Skip the return address register field.
if (auto Err = RecordReader.skip(1))
return Err;
uint64_t AugmentationDataLength = 0;
if (auto Err = RecordReader.readULEB128(AugmentationDataLength))
return Err;
uint32_t AugmentationDataStartOffset = RecordReader.getOffset();
uint8_t *NextField = &AugInfo->Fields[0];
while (uint8_t Field = *NextField++) {
switch (Field) {
case 'L': {
CIEInfo.FDEsHaveLSDAField = true;
uint8_t LSDAPointerEncoding;
if (auto Err = RecordReader.readInteger(LSDAPointerEncoding))
return Err;
if (!isSupportedPointerEncoding(LSDAPointerEncoding))
return make_error<JITLinkError>(
"Unsupported LSDA pointer encoding " +
formatv("{0:x2}", LSDAPointerEncoding) + " in CIE at " +
formatv("{0:x16}", CIESymbol.getAddress()));
CIEInfo.LSDAPointerEncoding = LSDAPointerEncoding;
break;
}
case 'P': {
uint8_t PersonalityPointerEncoding = 0;
if (auto Err = RecordReader.readInteger(PersonalityPointerEncoding))
return Err;
if (PersonalityPointerEncoding !=
(dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
dwarf::DW_EH_PE_sdata4))
return make_error<JITLinkError>(
"Unspported personality pointer "
"encoding " +
formatv("{0:x2}", PersonalityPointerEncoding) + " in CIE at " +
formatv("{0:x16}", CIESymbol.getAddress()));
uint32_t PersonalityPointerAddress;
if (auto Err = RecordReader.readInteger(PersonalityPointerAddress))
return Err;
break;
}
case 'R': {
uint8_t FDEPointerEncoding;
if (auto Err = RecordReader.readInteger(FDEPointerEncoding))
return Err;
if (!isSupportedPointerEncoding(FDEPointerEncoding))
return make_error<JITLinkError>(
"Unsupported FDE pointer encoding " +
formatv("{0:x2}", FDEPointerEncoding) + " in CIE at " +
formatv("{0:x16}", CIESymbol.getAddress()));
CIEInfo.FDEPointerEncoding = FDEPointerEncoding;
break;
}
default:
llvm_unreachable("Invalid augmentation string field");
}
}
if (RecordReader.getOffset() - AugmentationDataStartOffset >
AugmentationDataLength)
return make_error<JITLinkError>("Read past the end of the augmentation "
"data while parsing fields");
assert(!PC.CIEInfos.count(CIESymbol.getAddress()) &&
"Multiple CIEs recorded at the same address?");
PC.CIEInfos[CIESymbol.getAddress()] = std::move(CIEInfo);
return Error::success();
}
Error EHFrameEdgeFixer::processFDE(ParseContext &PC, Block &B,
size_t RecordOffset, size_t RecordLength,
size_t CIEDeltaFieldOffset,
uint32_t CIEDelta,
BlockEdgeMap &BlockEdges) {
LLVM_DEBUG(dbgs() << " Record is FDE\n");
JITTargetAddress RecordAddress = B.getAddress() + RecordOffset;
auto RecordContent = B.getContent().substr(RecordOffset, RecordLength);
BinaryStreamReader RecordReader(RecordContent, PC.G.getEndianness());
// Skip past the CIE delta field: we've already read this far.
RecordReader.setOffset(CIEDeltaFieldOffset + 4);
auto &FDESymbol =
PC.G.addAnonymousSymbol(B, RecordOffset, RecordLength, false, false);
CIEInformation *CIEInfo = nullptr;
{
// Process the CIE pointer field.
auto CIEEdgeItr = BlockEdges.find(RecordOffset + CIEDeltaFieldOffset);
JITTargetAddress CIEAddress =
RecordAddress + CIEDeltaFieldOffset - CIEDelta;
if (CIEEdgeItr == BlockEdges.end()) {
LLVM_DEBUG({
dbgs() << " Adding edge at "
<< formatv("{0:x16}", RecordAddress + CIEDeltaFieldOffset)
<< " to CIE at: " << formatv("{0:x16}", CIEAddress) << "\n";
});
if (auto CIEInfoOrErr = PC.findCIEInfo(CIEAddress))
CIEInfo = *CIEInfoOrErr;
else
return CIEInfoOrErr.takeError();
assert(CIEInfo->CIESymbol && "CIEInfo has no CIE symbol set");
B.addEdge(NegDelta32, RecordOffset + CIEDeltaFieldOffset,
*CIEInfo->CIESymbol, 0);
} else {
LLVM_DEBUG({
dbgs() << " Already has edge at "
<< formatv("{0:x16}", RecordAddress + CIEDeltaFieldOffset)
<< " to CIE at " << formatv("{0:x16}", CIEAddress) << "\n";
});
auto &EI = CIEEdgeItr->second;
if (EI.Addend)
return make_error<JITLinkError>(
"CIE edge at " +
formatv("{0:x16}", RecordAddress + CIEDeltaFieldOffset) +
" has non-zero addend");
if (auto CIEInfoOrErr = PC.findCIEInfo(EI.Target->getAddress()))
CIEInfo = *CIEInfoOrErr;
else
return CIEInfoOrErr.takeError();
}
}
{
// Process the PC-Begin field.
Block *PCBeginBlock = nullptr;
JITTargetAddress PCBeginFieldOffset = RecordReader.getOffset();
auto PCEdgeItr = BlockEdges.find(RecordOffset + PCBeginFieldOffset);
if (PCEdgeItr == BlockEdges.end()) {
auto PCBeginPtrInfo =
readEncodedPointer(CIEInfo->FDEPointerEncoding,
RecordAddress + PCBeginFieldOffset, RecordReader);
if (!PCBeginPtrInfo)
return PCBeginPtrInfo.takeError();
JITTargetAddress PCBegin = PCBeginPtrInfo->first;
Edge::Kind PCBeginEdgeKind = PCBeginPtrInfo->second;
LLVM_DEBUG({
dbgs() << " Adding edge at "
<< formatv("{0:x16}", RecordAddress + PCBeginFieldOffset)
<< " to PC at " << formatv("{0:x16}", PCBegin) << "\n";
});
auto PCBeginSym = getOrCreateSymbol(PC, PCBegin);
if (!PCBeginSym)
return PCBeginSym.takeError();
B.addEdge(PCBeginEdgeKind, RecordOffset + PCBeginFieldOffset, *PCBeginSym,
0);
PCBeginBlock = &PCBeginSym->getBlock();
} else {
auto &EI = PCEdgeItr->second;
LLVM_DEBUG({
dbgs() << " Already has edge at "
<< formatv("{0:x16}", RecordAddress + PCBeginFieldOffset)
<< " to PC at " << formatv("{0:x16}", EI.Target->getAddress());
if (EI.Addend)
dbgs() << " + " << formatv("{0:x16}", EI.Addend);
dbgs() << "\n";
});
// Make sure the existing edge points at a defined block.
if (!EI.Target->isDefined()) {
auto EdgeAddr = RecordAddress + PCBeginFieldOffset;
return make_error<JITLinkError>("FDE edge at " +
formatv("{0:x16}", EdgeAddr) +
" points at external block");
}
PCBeginBlock = &EI.Target->getBlock();
if (auto Err = RecordReader.skip(
getPointerEncodingDataSize(CIEInfo->FDEPointerEncoding)))
return Err;
}
// Add a keep-alive edge from the FDE target to the FDE to ensure that the
// FDE is kept alive if its target is.
assert(PCBeginBlock && "PC-begin block not recorded");
LLVM_DEBUG({
dbgs() << " Adding keep-alive edge from target at "
<< formatv("{0:x16}", PCBeginBlock->getAddress()) << " to FDE at "
<< formatv("{0:x16}", RecordAddress) << "\n";
});
PCBeginBlock->addEdge(Edge::KeepAlive, 0, FDESymbol, 0);
}
// Skip over the PC range size field.
if (auto Err = RecordReader.skip(
getPointerEncodingDataSize(CIEInfo->FDEPointerEncoding)))
return Err;
if (CIEInfo->FDEsHaveLSDAField) {
uint64_t AugmentationDataSize;
if (auto Err = RecordReader.readULEB128(AugmentationDataSize))
return Err;
JITTargetAddress LSDAFieldOffset = RecordReader.getOffset();
auto LSDAEdgeItr = BlockEdges.find(RecordOffset + LSDAFieldOffset);
if (LSDAEdgeItr == BlockEdges.end()) {
auto LSDAPointerInfo =
readEncodedPointer(CIEInfo->LSDAPointerEncoding,
RecordAddress + LSDAFieldOffset, RecordReader);
if (!LSDAPointerInfo)
return LSDAPointerInfo.takeError();
JITTargetAddress LSDA = LSDAPointerInfo->first;
Edge::Kind LSDAEdgeKind = LSDAPointerInfo->second;
auto LSDASym = getOrCreateSymbol(PC, LSDA);
if (!LSDASym)
return LSDASym.takeError();
LLVM_DEBUG({
dbgs() << " Adding edge at "
<< formatv("{0:x16}", RecordAddress + LSDAFieldOffset)
<< " to LSDA at " << formatv("{0:x16}", LSDA) << "\n";
});
B.addEdge(LSDAEdgeKind, RecordOffset + LSDAFieldOffset, *LSDASym, 0);
} else {
LLVM_DEBUG({
auto &EI = LSDAEdgeItr->second;
dbgs() << " Already has edge at "
<< formatv("{0:x16}", RecordAddress + LSDAFieldOffset)
<< " to LSDA at " << formatv("{0:x16}", EI.Target->getAddress());
if (EI.Addend)
dbgs() << " + " << formatv("{0:x16}", EI.Addend);
dbgs() << "\n";
});
if (auto Err = RecordReader.skip(AugmentationDataSize))
return Err;
}
} else {
LLVM_DEBUG(dbgs() << " Record does not have LSDA field.\n");
}
return Error::success();
}
Expected<EHFrameEdgeFixer::AugmentationInfo>
EHFrameEdgeFixer::parseAugmentationString(BinaryStreamReader &RecordReader) {
AugmentationInfo AugInfo;
uint8_t NextChar;
uint8_t *NextField = &AugInfo.Fields[0];
if (auto Err = RecordReader.readInteger(NextChar))
return std::move(Err);
while (NextChar != 0) {
switch (NextChar) {
case 'z':
AugInfo.AugmentationDataPresent = true;
break;
case 'e':
if (auto Err = RecordReader.readInteger(NextChar))
return std::move(Err);
if (NextChar != 'h')
return make_error<JITLinkError>("Unrecognized substring e" +
Twine(NextChar) +
" in augmentation string");
AugInfo.EHDataFieldPresent = true;
break;
case 'L':
case 'P':
case 'R':
*NextField++ = NextChar;
break;
default:
return make_error<JITLinkError>("Unrecognized character " +
Twine(NextChar) +
" in augmentation string");
}
if (auto Err = RecordReader.readInteger(NextChar))
return std::move(Err);
}
return std::move(AugInfo);
}
bool EHFrameEdgeFixer::isSupportedPointerEncoding(uint8_t PointerEncoding) {
using namespace dwarf;
// We only support PC-rel for now.
if ((PointerEncoding & 0x70) != DW_EH_PE_pcrel)
return false;
// readEncodedPointer does not handle indirect.
if (PointerEncoding & DW_EH_PE_indirect)
return false;
// Supported datatypes.
switch (PointerEncoding & 0xf) {
case DW_EH_PE_absptr:
case DW_EH_PE_udata4:
case DW_EH_PE_udata8:
case DW_EH_PE_sdata4:
case DW_EH_PE_sdata8:
return true;
}
return false;
}
unsigned EHFrameEdgeFixer::getPointerEncodingDataSize(uint8_t PointerEncoding) {
using namespace dwarf;
assert(isSupportedPointerEncoding(PointerEncoding) &&
"Unsupported pointer encoding");
switch (PointerEncoding & 0xf) {
case DW_EH_PE_absptr:
return PointerSize;
case DW_EH_PE_udata4:
case DW_EH_PE_sdata4:
return 4;
case DW_EH_PE_udata8:
case DW_EH_PE_sdata8:
return 8;
default:
llvm_unreachable("Unsupported encoding");
}
}
Expected<std::pair<JITTargetAddress, Edge::Kind>>
EHFrameEdgeFixer::readEncodedPointer(uint8_t PointerEncoding,
JITTargetAddress PointerFieldAddress,
BinaryStreamReader &RecordReader) {
static_assert(sizeof(JITTargetAddress) == sizeof(uint64_t),
"Result must be able to hold a uint64_t");
assert(isSupportedPointerEncoding(PointerEncoding) &&
"Unsupported pointer encoding");
using namespace dwarf;
// Isolate data type, remap absptr to udata4 or udata8. This relies on us
// having verified that the graph uses 32-bit or 64-bit pointers only at the
// start of this pass.
uint8_t EffectiveType = PointerEncoding & 0xf;
if (EffectiveType == DW_EH_PE_absptr)
EffectiveType = (PointerSize == 8) ? DW_EH_PE_udata8 : DW_EH_PE_udata4;
JITTargetAddress Addr;
Edge::Kind PointerEdgeKind;
switch (EffectiveType) {
case DW_EH_PE_udata4: {
uint32_t Val;
if (auto Err = RecordReader.readInteger(Val))
return std::move(Err);
Addr = PointerFieldAddress + Val;
PointerEdgeKind = Delta32;
break;
}
case DW_EH_PE_udata8: {
uint64_t Val;
if (auto Err = RecordReader.readInteger(Val))
return std::move(Err);
Addr = PointerFieldAddress + Val;
PointerEdgeKind = Delta64;
break;
}
case DW_EH_PE_sdata4: {
int32_t Val;
if (auto Err = RecordReader.readInteger(Val))
return std::move(Err);
Addr = PointerFieldAddress + Val;
PointerEdgeKind = Delta32;
break;
}
case DW_EH_PE_sdata8: {
int64_t Val;
if (auto Err = RecordReader.readInteger(Val))
return std::move(Err);
Addr = PointerFieldAddress + Val;
PointerEdgeKind = Delta64;
break;
}
}
if (PointerEdgeKind == Edge::Invalid)
return make_error<JITLinkError>(
"Unspported edge kind for encoded pointer at " +
formatv("{0:x}", PointerFieldAddress));
return std::make_pair(Addr, Delta64);
}
Expected<Symbol &> EHFrameEdgeFixer::getOrCreateSymbol(ParseContext &PC,
JITTargetAddress Addr) {
Symbol *CanonicalSym = nullptr;
auto UpdateCanonicalSym = [&](Symbol *Sym) {
if (!CanonicalSym || Sym->getLinkage() < CanonicalSym->getLinkage() ||
Sym->getScope() < CanonicalSym->getScope() ||
(Sym->hasName() && !CanonicalSym->hasName()) ||
Sym->getName() < CanonicalSym->getName())
CanonicalSym = Sym;
};
if (auto *SymbolsAtAddr = PC.AddrToSyms.getSymbolsAt(Addr))
for (auto *Sym : *SymbolsAtAddr)
UpdateCanonicalSym(Sym);
// If we found an existing symbol at the given address then use it.
if (CanonicalSym)
return *CanonicalSym;
// Otherwise search for a block covering the address and create a new symbol.
auto *B = PC.AddrToBlock.getBlockCovering(Addr);
if (!B)
return make_error<JITLinkError>("No symbol or block covering address " +
formatv("{0:x16}", Addr));
return PC.G.addAnonymousSymbol(*B, Addr - B->getAddress(), 0, false, false);
}
EHFrameRegistrar::~EHFrameRegistrar() {}
Error InProcessEHFrameRegistrar::registerEHFrames(
JITTargetAddress EHFrameSectionAddr, size_t EHFrameSectionSize) {
return orc::registerEHFrameSection(
jitTargetAddressToPointer<void *>(EHFrameSectionAddr),
EHFrameSectionSize);
}
Error InProcessEHFrameRegistrar::deregisterEHFrames(
JITTargetAddress EHFrameSectionAddr, size_t EHFrameSectionSize) {
return orc::deregisterEHFrameSection(
jitTargetAddressToPointer<void *>(EHFrameSectionAddr),
EHFrameSectionSize);
}
LinkGraphPassFunction
createEHFrameRecorderPass(const Triple &TT,
StoreFrameRangeFunction StoreRangeAddress) {
const char *EHFrameSectionName = nullptr;
if (TT.getObjectFormat() == Triple::MachO)
EHFrameSectionName = "__eh_frame";
else
EHFrameSectionName = ".eh_frame";
auto RecordEHFrame =
[EHFrameSectionName,
StoreFrameRange = std::move(StoreRangeAddress)](LinkGraph &G) -> Error {
// Search for a non-empty eh-frame and record the address of the first
// symbol in it.
JITTargetAddress Addr = 0;
size_t Size = 0;
if (auto *S = G.findSectionByName(EHFrameSectionName)) {
auto R = SectionRange(*S);
Addr = R.getStart();
Size = R.getSize();
}
if (Addr == 0 && Size != 0)
return make_error<JITLinkError>("__eh_frame section can not have zero "
"address with non-zero size");
StoreFrameRange(Addr, Size);
return Error::success();
};
return RecordEHFrame;
}
} // end namespace jitlink
} // end namespace llvm