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MC: Refactor ObjectSymbolizer to make relocation/section info generation lazy.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188878 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ahmed Bougacha 2013-08-21 07:28:07 +00:00
parent 07e8f8f643
commit cdef37a9d8
2 changed files with 166 additions and 143 deletions
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27
include/llvm/MC/MCObjectSymbolizer.h
View File

@ -32,22 +32,14 @@ class MCObjectSymbolizer : public MCSymbolizer {
protected:
const object::ObjectFile *Obj;
typedef DenseMap<uint64_t, object::RelocationRef> AddrToRelocMap;
typedef std::vector<object::SectionRef> SortedSectionList;
SortedSectionList SortedSections;
// Map a load address to the first relocation that applies there. As far as I
// know, if there are several relocations at the exact same address, they are
// related and the others can be determined from the first that was found in
// the relocation table. For instance, on x86-64 mach-o, a SUBTRACTOR
// relocation (referencing the minuend symbol) is followed by an UNSIGNED
// relocation (referencing the subtrahend symbol).
AddrToRelocMap AddrToReloc;
// Helpers around SortedSections.
SortedSectionList::const_iterator findSectionContaining(uint64_t Addr) const;
void insertSection(object::SectionRef Section);
const object::RelocationRef *findRelocationAt(uint64_t Addr);
const object::SectionRef *findSectionContaining(uint64_t Addr);
MCObjectSymbolizer(MCContext &Ctx, OwningPtr<MCRelocationInfo> &RelInfo,
const object::ObjectFile *Obj);
@ -56,9 +48,9 @@ public:
/// \name Overridden MCSymbolizer methods:
/// @{
bool tryAddingSymbolicOperand(MCInst &MI, raw_ostream &cStream,
int64_t Value,
uint64_t Address, bool IsBranch,
uint64_t Offset, uint64_t InstSize);
int64_t Value, uint64_t Address,
bool IsBranch, uint64_t Offset,
uint64_t InstSize);
void tryAddingPcLoadReferenceComment(raw_ostream &cStream,
int64_t Value, uint64_t Address);
@ -68,6 +60,15 @@ public:
static MCObjectSymbolizer *
createObjectSymbolizer(MCContext &Ctx, OwningPtr<MCRelocationInfo> &RelInfo,
const object::ObjectFile *Obj);
private:
typedef DenseMap<uint64_t, object::RelocationRef> AddrToRelocMap;
typedef std::vector<object::SectionRef> SortedSectionList;
SortedSectionList SortedSections;
AddrToRelocMap AddrToReloc;
void buildSectionList();
void buildRelocationByAddrMap();
};
}

282
lib/MC/MCObjectSymbolizer.cpp
View File

@ -28,47 +28,170 @@ namespace {
class MCMachObjectSymbolizer : public MCObjectSymbolizer {
public:
MCMachObjectSymbolizer(MCContext &Ctx, OwningPtr<MCRelocationInfo> &RelInfo,
const object::MachOObjectFile *MachOOF)
: MCObjectSymbolizer(Ctx, RelInfo, MachOOF)
{}
const MachOObjectFile *MOOF) {}
void tryAddingPcLoadReferenceComment(raw_ostream &cStream,
int64_t Value, uint64_t Address) {
AddrToRelocMap::iterator RI = AddrToReloc.find(Address);
if (RI != AddrToReloc.end()) {
const MCExpr *RelExpr = RelInfo->createExprForRelocation(RI->second);
if (!RelExpr || RelExpr->EvaluateAsAbsolute(Value) == false)
return;
}
uint64_t Addr = Value;
SortedSectionList::const_iterator SI = findSectionContaining(Addr);
if (SI != SortedSections.end()) {
const SectionRef &S = *SI;
StringRef Name; S.getName(Name);
uint64_t SAddr; S.getAddress(SAddr);
if (Name == "__cstring") {
StringRef Contents;
S.getContents(Contents);
Contents = Contents.substr(Addr - SAddr);
cStream << " ## literal pool for: "
<< Contents.substr(0, Contents.find_first_of(0));
}
}
}
int64_t Value,
uint64_t Address) LLVM_OVERRIDE;
};
} // End unnamed namespace
void MCMachObjectSymbolizer::
tryAddingPcLoadReferenceComment(raw_ostream &cStream, int64_t Value,
uint64_t Address) {
if (const RelocationRef *R = findRelocationAt(Address)) {
const MCExpr *RelExpr = RelInfo->createExprForRelocation(*R);
if (!RelExpr || RelExpr->EvaluateAsAbsolute(Value) == false)
return;
}
uint64_t Addr = Value;
if (const SectionRef *S = findSectionContaining(Addr)) {
StringRef Name; S->getName(Name);
uint64_t SAddr; S->getAddress(SAddr);
if (Name == "__cstring") {
StringRef Contents;
S->getContents(Contents);
Contents = Contents.substr(Addr - SAddr);
cStream << " ## literal pool for: "
<< Contents.substr(0, Contents.find_first_of(0));
}
}
}
//===- MCObjectSymbolizer -------------------------------------------------===//
MCObjectSymbolizer::MCObjectSymbolizer(MCContext &Ctx,
OwningPtr<MCRelocationInfo> &RelInfo,
const ObjectFile *Obj)
: MCSymbolizer(Ctx, RelInfo), Obj(Obj), SortedSections(), AddrToReloc() {
}
bool MCObjectSymbolizer::
tryAddingSymbolicOperand(MCInst &MI, raw_ostream &cStream,
int64_t Value, uint64_t Address, bool IsBranch,
uint64_t Offset, uint64_t InstSize) {
if (const RelocationRef *R = findRelocationAt(Address + Offset)) {
if (const MCExpr *RelExpr = RelInfo->createExprForRelocation(*R)) {
MI.addOperand(MCOperand::CreateExpr(RelExpr));
return true;
}
// Only try to create a symbol+offset expression if there is no relocation.
return false;
}
// Interpret Value as a branch target.
if (IsBranch == false)
return false;
uint64_t UValue = Value;
// FIXME: map instead of looping each time?
error_code ec;
for (section_iterator SI = Obj->begin_sections(),
SE = Obj->end_sections();
SI != SE;
SI.increment(ec)) {
for (symbol_iterator SI = Obj->begin_symbols(), SE = Obj->end_symbols();
SI != SE; SI.increment(ec)) {
if (ec) break;
uint64_t SymAddr; SI->getAddress(SymAddr);
uint64_t SymSize; SI->getSize(SymSize);
StringRef SymName; SI->getName(SymName);
SymbolRef::Type SymType; SI->getType(SymType);
if (SymAddr == UnknownAddressOrSize || SymSize == UnknownAddressOrSize
|| SymName.empty() || SymType != SymbolRef::ST_Function)
continue;
if ( SymAddr == UValue ||
(SymAddr <= UValue && SymAddr + SymSize > UValue)) {
MCSymbol *Sym = Ctx.GetOrCreateSymbol(SymName);
const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
if (SymAddr != UValue) {
const MCExpr *Off = MCConstantExpr::Create(UValue - SymAddr, Ctx);
Expr = MCBinaryExpr::CreateAdd(Expr, Off, Ctx);
}
MI.addOperand(MCOperand::CreateExpr(Expr));
return true;
}
}
return false;
}
void MCObjectSymbolizer::
tryAddingPcLoadReferenceComment(raw_ostream &cStream,
int64_t Value, uint64_t Address) {
}
StringRef MCObjectSymbolizer::findExternalFunctionAt(uint64_t Addr) {
return StringRef();
}
MCObjectSymbolizer *
MCObjectSymbolizer::createObjectSymbolizer(MCContext &Ctx,
OwningPtr<MCRelocationInfo> &RelInfo,
const ObjectFile *Obj) {
if (const MachOObjectFile *MOOF = dyn_cast<MachOObjectFile>(Obj))
return new MCMachObjectSymbolizer(Ctx, RelInfo, MOOF);
return new MCObjectSymbolizer(Ctx, RelInfo, Obj);
}
// SortedSections implementation.
static bool SectionStartsBefore(const SectionRef &S, uint64_t Addr) {
uint64_t SAddr; S.getAddress(SAddr);
return SAddr < Addr;
}
const SectionRef *MCObjectSymbolizer::findSectionContaining(uint64_t Addr) {
if (SortedSections.empty())
buildSectionList();
SortedSectionList::iterator
EndIt = SortedSections.end(),
It = std::lower_bound(SortedSections.begin(), EndIt,
Addr, SectionStartsBefore);
if (It == EndIt)
return 0;
uint64_t SAddr; It->getAddress(SAddr);
uint64_t SSize; It->getSize(SSize);
if (Addr >= SAddr + SSize)
return 0;
return &*It;
}
const RelocationRef *MCObjectSymbolizer::findRelocationAt(uint64_t Addr) {
if (AddrToReloc.empty())
buildRelocationByAddrMap();
AddrToRelocMap::const_iterator RI = AddrToReloc.find(Addr);
if (RI == AddrToReloc.end())
return 0;
return &RI->second;
}
void MCObjectSymbolizer::buildSectionList() {
error_code ec;
for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
SI != SE; SI.increment(ec)) {
if (ec) break;
bool RequiredForExec; SI->isRequiredForExecution(RequiredForExec);
if (RequiredForExec == false)
continue;
uint64_t SAddr; SI->getAddress(SAddr);
uint64_t SSize; SI->getSize(SSize);
SortedSectionList::iterator It = std::lower_bound(SortedSections.begin(),
SortedSections.end(),
SAddr,
SectionStartsBefore);
if (It != SortedSections.end()) {
uint64_t FoundSAddr; It->getAddress(FoundSAddr);
if (FoundSAddr < SAddr + SSize)
llvm_unreachable("Inserting overlapping sections");
}
SortedSections.insert(It, *SI);
}
}
void MCObjectSymbolizer::buildRelocationByAddrMap() {
error_code ec;
for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
SI != SE; SI.increment(ec)) {
if (ec) break;
section_iterator RelSecI = SI->getRelocatedSection();
@ -80,7 +203,6 @@ MCObjectSymbolizer::MCObjectSymbolizer(MCContext &Ctx,
bool RequiredForExec; RelSecI->isRequiredForExecution(RequiredForExec);
if (RequiredForExec == false || Size == 0)
continue;
insertSection(*SI);
for (relocation_iterator RI = SI->begin_relocations(),
RE = SI->end_relocations();
RI != RE;
@ -112,103 +234,3 @@ MCObjectSymbolizer::MCObjectSymbolizer(MCContext &Ctx,
}
}
}
bool MCObjectSymbolizer::
tryAddingSymbolicOperand(MCInst &MI, raw_ostream &cStream,
int64_t Value, uint64_t Address, bool IsBranch,
uint64_t Offset, uint64_t InstSize) {
AddrToRelocMap::iterator RI = AddrToReloc.find(Address + Offset);
if (RI != AddrToReloc.end()) {
if (const MCExpr *RelExpr = RelInfo->createExprForRelocation(RI->second)) {
MI.addOperand(MCOperand::CreateExpr(RelExpr));
return true;
}
// Only try to create a symbol+offset expression if there is no relocation.
return false;
}
// Interpret Value as a branch target.
if (IsBranch == false)
return false;
uint64_t UValue = Value;
// FIXME: map instead of looping each time?
error_code ec;
for (symbol_iterator SI = Obj->begin_symbols(),
SE = Obj->end_symbols();
SI != SE;
SI.increment(ec)) {
if (ec) break;
uint64_t SymAddr; SI->getAddress(SymAddr);
uint64_t SymSize; SI->getSize(SymSize);
StringRef SymName; SI->getName(SymName);
SymbolRef::Type SymType; SI->getType(SymType);
if (SymAddr == UnknownAddressOrSize || SymSize == UnknownAddressOrSize
|| SymName.empty() || SymType != SymbolRef::ST_Function)
continue;
if ( SymAddr == UValue ||
(SymAddr <= UValue && SymAddr + SymSize > UValue)) {
MCSymbol *Sym = Ctx.GetOrCreateSymbol(SymName);
const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
if (SymAddr != UValue) {
const MCExpr *Off = MCConstantExpr::Create(UValue - SymAddr, Ctx);
Expr = MCBinaryExpr::CreateAdd(Expr, Off, Ctx);
}
MI.addOperand(MCOperand::CreateExpr(Expr));
return true;
}
}
return false;
}
void MCObjectSymbolizer::
tryAddingPcLoadReferenceComment(raw_ostream &cStream,
int64_t Value, uint64_t Address) {
}
MCObjectSymbolizer *
MCObjectSymbolizer::createObjectSymbolizer(MCContext &Ctx,
OwningPtr<MCRelocationInfo> &RelInfo,
const ObjectFile *Obj) {
if (const MachOObjectFile *MachOOF = dyn_cast<MachOObjectFile>(Obj)) {
return new MCMachObjectSymbolizer(Ctx, RelInfo, MachOOF);
}
return new MCObjectSymbolizer(Ctx, RelInfo, Obj);
}
// SortedSections implementation.
static bool SectionStartsBefore(const SectionRef &S, uint64_t Addr) {
uint64_t SAddr; S.getAddress(SAddr);
return SAddr < Addr;
}
MCObjectSymbolizer::SortedSectionList::const_iterator
MCObjectSymbolizer::findSectionContaining(uint64_t Addr) const {
SortedSectionList::const_iterator
EndIt = SortedSections.end(),
It = std::lower_bound(SortedSections.begin(), EndIt,
Addr, SectionStartsBefore);
if (It == EndIt)
return It;
uint64_t SAddr; It->getAddress(SAddr);
uint64_t SSize; It->getSize(SSize);
if (Addr >= SAddr + SSize)
return EndIt;
return It;
}
void MCObjectSymbolizer::insertSection(SectionRef Sec) {
uint64_t SAddr; Sec.getAddress(SAddr);
uint64_t SSize; Sec.getSize(SSize);
SortedSectionList::iterator It = std::lower_bound(SortedSections.begin(),
SortedSections.end(),
SAddr,
SectionStartsBefore);
if (It != SortedSections.end()) {
uint64_t FoundSAddr; It->getAddress(FoundSAddr);
if (FoundSAddr < SAddr + SSize)
llvm_unreachable("Inserting overlapping sections");
}
SortedSections.insert(It, Sec);
}