DwarfException.cpp [plain text]
#include "DwarfException.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
DwarfException::DwarfException(AsmPrinter *A)
: Asm(A), MMI(Asm->MMI) {}
DwarfException::~DwarfException() {}
unsigned DwarfException::SharedTypeIds(const LandingPadInfo *L,
const LandingPadInfo *R) {
const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
unsigned LSize = LIds.size(), RSize = RIds.size();
unsigned MinSize = LSize < RSize ? LSize : RSize;
unsigned Count = 0;
for (; Count != MinSize; ++Count)
if (LIds[Count] != RIds[Count])
return Count;
return Count;
}
bool DwarfException::PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
unsigned LSize = LIds.size(), RSize = RIds.size();
unsigned MinSize = LSize < RSize ? LSize : RSize;
for (unsigned i = 0; i != MinSize; ++i)
if (LIds[i] != RIds[i])
return LIds[i] < RIds[i];
return LSize < RSize;
}
unsigned DwarfException::
ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
SmallVectorImpl<ActionEntry> &Actions,
SmallVectorImpl<unsigned> &FirstActions) {
const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
SmallVector<int, 16> FilterOffsets;
FilterOffsets.reserve(FilterIds.size());
int Offset = -1;
for (std::vector<unsigned>::const_iterator
I = FilterIds.begin(), E = FilterIds.end(); I != E; ++I) {
FilterOffsets.push_back(Offset);
Offset -= MCAsmInfo::getULEB128Size(*I);
}
FirstActions.reserve(LandingPads.size());
int FirstAction = 0;
unsigned SizeActions = 0;
const LandingPadInfo *PrevLPI = 0;
for (SmallVectorImpl<const LandingPadInfo *>::const_iterator
I = LandingPads.begin(), E = LandingPads.end(); I != E; ++I) {
const LandingPadInfo *LPI = *I;
const std::vector<int> &TypeIds = LPI->TypeIds;
unsigned NumShared = PrevLPI ? SharedTypeIds(LPI, PrevLPI) : 0;
unsigned SizeSiteActions = 0;
if (NumShared < TypeIds.size()) {
unsigned SizeAction = 0;
unsigned PrevAction = (unsigned)-1;
if (NumShared) {
unsigned SizePrevIds = PrevLPI->TypeIds.size();
assert(Actions.size());
PrevAction = Actions.size() - 1;
SizeAction =
MCAsmInfo::getSLEB128Size(Actions[PrevAction].NextAction) +
MCAsmInfo::getSLEB128Size(Actions[PrevAction].ValueForTypeID);
for (unsigned j = NumShared; j != SizePrevIds; ++j) {
assert(PrevAction != (unsigned)-1 && "PrevAction is invalid!");
SizeAction -=
MCAsmInfo::getSLEB128Size(Actions[PrevAction].ValueForTypeID);
SizeAction += -Actions[PrevAction].NextAction;
PrevAction = Actions[PrevAction].Previous;
}
}
for (unsigned J = NumShared, M = TypeIds.size(); J != M; ++J) {
int TypeID = TypeIds[J];
assert(-1 - TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
unsigned SizeTypeID = MCAsmInfo::getSLEB128Size(ValueForTypeID);
int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
SizeAction = SizeTypeID + MCAsmInfo::getSLEB128Size(NextAction);
SizeSiteActions += SizeAction;
ActionEntry Action = { ValueForTypeID, NextAction, PrevAction };
Actions.push_back(Action);
PrevAction = Actions.size() - 1;
}
FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
}
FirstActions.push_back(FirstAction);
SizeActions += SizeSiteActions;
PrevLPI = LPI;
}
return SizeActions;
}
bool DwarfException::CallToNoUnwindFunction(const MachineInstr *MI) {
assert(MI->isCall() && "This should be a call instruction!");
bool MarkedNoUnwind = false;
bool SawFunc = false;
for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) {
const MachineOperand &MO = MI->getOperand(I);
if (!MO.isGlobal()) continue;
const Function *F = dyn_cast<Function>(MO.getGlobal());
if (F == 0) continue;
if (SawFunc) {
MarkedNoUnwind = false;
break;
}
MarkedNoUnwind = F->doesNotThrow();
SawFunc = true;
}
return MarkedNoUnwind;
}
void DwarfException::
ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
const RangeMapType &PadMap,
const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
const SmallVectorImpl<unsigned> &FirstActions) {
MCSymbol *LastLabel = 0;
bool SawPotentiallyThrowing = false;
bool PreviousIsInvoke = false;
for (MachineFunction::const_iterator I = Asm->MF->begin(), E = Asm->MF->end();
I != E; ++I) {
for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
MI != E; ++MI) {
if (!MI->isLabel()) {
if (MI->isCall())
SawPotentiallyThrowing |= !CallToNoUnwindFunction(MI);
continue;
}
MCSymbol *BeginLabel = MI->getOperand(0).getMCSymbol();
if (BeginLabel == LastLabel)
SawPotentiallyThrowing = false;
RangeMapType::const_iterator L = PadMap.find(BeginLabel);
if (L == PadMap.end())
continue;
const PadRange &P = L->second;
const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
"Inconsistent landing pad map!");
if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) {
CallSiteEntry Site = { LastLabel, BeginLabel, 0, 0 };
CallSites.push_back(Site);
PreviousIsInvoke = false;
}
LastLabel = LandingPad->EndLabels[P.RangeIndex];
assert(BeginLabel && LastLabel && "Invalid landing pad!");
if (!LandingPad->LandingPadLabel) {
PreviousIsInvoke = false;
} else {
CallSiteEntry Site = {
BeginLabel,
LastLabel,
LandingPad->LandingPadLabel,
FirstActions[P.PadIndex]
};
if (PreviousIsInvoke && Asm->MAI->isExceptionHandlingDwarf()) {
CallSiteEntry &Prev = CallSites.back();
if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
Prev.EndLabel = Site.EndLabel;
continue;
}
}
if (Asm->MAI->isExceptionHandlingDwarf())
CallSites.push_back(Site);
else {
unsigned SiteNo = MMI->getCallSiteBeginLabel(BeginLabel);
if (CallSites.size() < SiteNo)
CallSites.resize(SiteNo);
CallSites[SiteNo - 1] = Site;
}
PreviousIsInvoke = true;
}
}
}
if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) {
CallSiteEntry Site = { LastLabel, 0, 0, 0 };
CallSites.push_back(Site);
}
}
void DwarfException::EmitExceptionTable() {
const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
SmallVector<const LandingPadInfo *, 64> LandingPads;
LandingPads.reserve(PadInfos.size());
for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
LandingPads.push_back(&PadInfos[i]);
std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
SmallVector<ActionEntry, 32> Actions;
SmallVector<unsigned, 64> FirstActions;
unsigned SizeActions=ComputeActionsTable(LandingPads, Actions, FirstActions);
RangeMapType PadMap;
for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
const LandingPadInfo *LandingPad = LandingPads[i];
for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
MCSymbol *BeginLabel = LandingPad->BeginLabels[j];
assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
PadRange P = { i, j };
PadMap[BeginLabel] = P;
}
}
SmallVector<CallSiteEntry, 64> CallSites;
ComputeCallSiteTable(CallSites, PadMap, LandingPads, FirstActions);
bool IsSJLJ = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true;
unsigned CallSiteTableLength;
if (IsSJLJ)
CallSiteTableLength = 0;
else {
unsigned SiteStartSize = 4; unsigned SiteLengthSize = 4; unsigned LandingPadSize = 4; CallSiteTableLength =
CallSites.size() * (SiteStartSize + SiteLengthSize + LandingPadSize);
}
for (unsigned i = 0, e = CallSites.size(); i < e; ++i) {
CallSiteTableLength += MCAsmInfo::getULEB128Size(CallSites[i].Action);
if (IsSJLJ)
CallSiteTableLength += MCAsmInfo::getULEB128Size(i);
}
const MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection();
unsigned TTypeEncoding;
unsigned TypeFormatSize;
if (!HaveTTData) {
TTypeEncoding = dwarf::DW_EH_PE_omit;
TypeFormatSize = Asm->getDataLayout().getPointerSize();
} else {
TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
TypeFormatSize = Asm->GetSizeOfEncodedValue(TTypeEncoding);
}
if (LSDASection)
Asm->OutStreamer.SwitchSection(LSDASection);
Asm->EmitAlignment(2);
MCSymbol *GCCETSym =
Asm->OutContext.GetOrCreateSymbol(Twine("GCC_except_table")+
Twine(Asm->getFunctionNumber()));
Asm->OutStreamer.EmitLabel(GCCETSym);
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("exception",
Asm->getFunctionNumber()));
if (IsSJLJ)
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("_LSDA_",
Asm->getFunctionNumber()));
Asm->EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
Asm->EmitEncodingByte(TTypeEncoding, "@TType");
unsigned SizeTypes = TypeInfos.size() * TypeFormatSize;
unsigned CallSiteTableLengthSize =
MCAsmInfo::getULEB128Size(CallSiteTableLength);
unsigned TTypeBaseOffset =
sizeof(int8_t) + CallSiteTableLengthSize + CallSiteTableLength + SizeActions + SizeTypes;
unsigned TTypeBaseOffsetSize = MCAsmInfo::getULEB128Size(TTypeBaseOffset);
unsigned TotalSize =
sizeof(int8_t) + sizeof(int8_t) + (HaveTTData ? TTypeBaseOffsetSize : 0) + TTypeBaseOffset; unsigned SizeAlign = (4 - TotalSize) & 3;
if (HaveTTData) {
Asm->EmitULEB128(TTypeBaseOffset, "@TType base offset", SizeAlign);
SizeAlign = 0;
}
bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
if (IsSJLJ) {
Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
unsigned idx = 0;
for (SmallVectorImpl<CallSiteEntry>::const_iterator
I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
const CallSiteEntry &S = *I;
if (VerboseAsm) {
Asm->OutStreamer.AddComment(">> Call Site " + Twine(idx) + " <<");
Asm->OutStreamer.AddComment(" On exception at call site "+Twine(idx));
}
Asm->EmitULEB128(idx);
if (VerboseAsm) {
if (S.Action == 0)
Asm->OutStreamer.AddComment(" Action: cleanup");
else
Asm->OutStreamer.AddComment(" Action: " +
Twine((S.Action - 1) / 2 + 1));
}
Asm->EmitULEB128(S.Action);
}
} else {
assert(Asm->MAI->isExceptionHandlingDwarf());
Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
unsigned Entry = 0;
for (SmallVectorImpl<CallSiteEntry>::const_iterator
I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
const CallSiteEntry &S = *I;
MCSymbol *EHFuncBeginSym =
Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
MCSymbol *BeginLabel = S.BeginLabel;
if (BeginLabel == 0)
BeginLabel = EHFuncBeginSym;
MCSymbol *EndLabel = S.EndLabel;
if (EndLabel == 0)
EndLabel = Asm->GetTempSymbol("eh_func_end", Asm->getFunctionNumber());
if (VerboseAsm)
Asm->OutStreamer.AddComment(">> Call Site " + Twine(++Entry) + " <<");
Asm->EmitLabelDifference(BeginLabel, EHFuncBeginSym, 4);
if (VerboseAsm)
Asm->OutStreamer.AddComment(Twine(" Call between ") +
BeginLabel->getName() + " and " +
EndLabel->getName());
Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
if (!S.PadLabel) {
if (VerboseAsm)
Asm->OutStreamer.AddComment(" has no landing pad");
Asm->OutStreamer.EmitIntValue(0, 4);
} else {
if (VerboseAsm)
Asm->OutStreamer.AddComment(Twine(" jumps to ") +
S.PadLabel->getName());
Asm->EmitLabelDifference(S.PadLabel, EHFuncBeginSym, 4);
}
if (VerboseAsm) {
if (S.Action == 0)
Asm->OutStreamer.AddComment(" On action: cleanup");
else
Asm->OutStreamer.AddComment(" On action: " +
Twine((S.Action - 1) / 2 + 1));
}
Asm->EmitULEB128(S.Action);
}
}
int Entry = 0;
for (SmallVectorImpl<ActionEntry>::const_iterator
I = Actions.begin(), E = Actions.end(); I != E; ++I) {
const ActionEntry &Action = *I;
if (VerboseAsm) {
Asm->OutStreamer.AddComment(">> Action Record " + Twine(++Entry) + " <<");
}
if (VerboseAsm) {
if (Action.ValueForTypeID > 0)
Asm->OutStreamer.AddComment(" Catch TypeInfo " +
Twine(Action.ValueForTypeID));
else if (Action.ValueForTypeID < 0)
Asm->OutStreamer.AddComment(" Filter TypeInfo " +
Twine(Action.ValueForTypeID));
else
Asm->OutStreamer.AddComment(" Cleanup");
}
Asm->EmitSLEB128(Action.ValueForTypeID);
if (VerboseAsm) {
if (Action.NextAction == 0) {
Asm->OutStreamer.AddComment(" No further actions");
} else {
unsigned NextAction = Entry + (Action.NextAction + 1) / 2;
Asm->OutStreamer.AddComment(" Continue to action "+Twine(NextAction));
}
}
Asm->EmitSLEB128(Action.NextAction);
}
EmitTypeInfos(TTypeEncoding);
Asm->EmitAlignment(2);
}
void DwarfException::EmitTypeInfos(unsigned TTypeEncoding) {
const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
int Entry = 0;
if (VerboseAsm && !TypeInfos.empty()) {
Asm->OutStreamer.AddComment(">> Catch TypeInfos <<");
Asm->OutStreamer.AddBlankLine();
Entry = TypeInfos.size();
}
for (std::vector<const GlobalVariable *>::const_reverse_iterator
I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
const GlobalVariable *GV = *I;
if (VerboseAsm)
Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--));
Asm->EmitTTypeReference(GV, TTypeEncoding);
}
if (VerboseAsm && !FilterIds.empty()) {
Asm->OutStreamer.AddComment(">> Filter TypeInfos <<");
Asm->OutStreamer.AddBlankLine();
Entry = 0;
}
for (std::vector<unsigned>::const_iterator
I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
unsigned TypeID = *I;
if (VerboseAsm) {
--Entry;
if (TypeID != 0)
Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry));
}
Asm->EmitULEB128(TypeID);
}
}
void DwarfException::EndModule() {
llvm_unreachable("Should be implemented");
}
void DwarfException::BeginFunction(const MachineFunction *MF) {
llvm_unreachable("Should be implemented");
}
void DwarfException::EndFunction() {
llvm_unreachable("Should be implemented");
}