#include "DwarfException.h"
#include "llvm/Module.h"
+#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineLocation.h"
-#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCAsmInfo.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Target/TargetFrameInfo.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/Target/Mangler.h"
+#include "llvm/DataLayout.h"
+#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/Dwarf.h"
-#include "llvm/Support/Timer.h"
-#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Twine.h"
using namespace llvm;
-static TimerGroup &getDwarfTimerGroup() {
- static TimerGroup DwarfTimerGroup("Dwarf Exception");
- return DwarfTimerGroup;
-}
-
-DwarfException::DwarfException(raw_ostream &OS, AsmPrinter *A,
- const MCAsmInfo *T)
- : Dwarf(OS, A, T, "eh"), shouldEmitTable(false), shouldEmitMoves(false),
- shouldEmitTableModule(false), shouldEmitMovesModule(false),
- ExceptionTimer(0) {
- if (TimePassesIsEnabled)
- ExceptionTimer = new Timer("Dwarf Exception Writer",
- getDwarfTimerGroup());
-}
-
-DwarfException::~DwarfException() {
- delete ExceptionTimer;
-}
-
-/// EmitCIE - Emit a Common Information Entry (CIE). This holds information that
-/// is shared among many Frame Description Entries. There is at least one CIE
-/// in every non-empty .debug_frame section.
-void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
- // Size and sign of stack growth.
- int stackGrowth =
- Asm->TM.getFrameInfo()->getStackGrowthDirection() ==
- TargetFrameInfo::StackGrowsUp ?
- TD->getPointerSize() : -TD->getPointerSize();
-
- // Begin eh frame section.
- Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering().getEHFrameSection());
-
- if (MAI->is_EHSymbolPrivate())
- O << MAI->getPrivateGlobalPrefix();
-
- O << "EH_frame" << Index << ":\n";
- EmitLabel("section_eh_frame", Index);
-
- // Define base labels.
- EmitLabel("eh_frame_common", Index);
-
- // Define the eh frame length.
- EmitDifference("eh_frame_common_end", Index,
- "eh_frame_common_begin", Index, true);
- Asm->EOL("Length of Common Information Entry");
-
- // EH frame header.
- EmitLabel("eh_frame_common_begin", Index);
- Asm->EmitInt32((int)0);
- Asm->EOL("CIE Identifier Tag");
- Asm->EmitInt8(dwarf::DW_CIE_VERSION);
- Asm->EOL("CIE Version");
-
- // The personality presence indicates that language specific information will
- // show up in the eh frame.
- Asm->EmitString(Personality ? "zPLR" : "zR");
- Asm->EOL("CIE Augmentation");
-
- // Round out reader.
- Asm->EmitULEB128Bytes(1);
- Asm->EOL("CIE Code Alignment Factor");
- Asm->EmitSLEB128Bytes(stackGrowth);
- Asm->EOL("CIE Data Alignment Factor");
- Asm->EmitInt8(RI->getDwarfRegNum(RI->getRARegister(), true));
- Asm->EOL("CIE Return Address Column");
-
- // If there is a personality, we need to indicate the function's location.
- if (Personality) {
- unsigned Encoding = 0;
- Asm->EmitULEB128Bytes(7);
- Asm->EOL("Augmentation Size");
-
- if (MAI->getNeedsIndirectEncoding()) {
- Encoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
- dwarf::DW_EH_PE_indirect;
- Asm->EmitInt8(Encoding);
- Asm->EOL("Personality", Encoding);
- } else {
- Encoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
- Asm->EmitInt8(Encoding);
- Asm->EOL("Personality", Encoding);
- }
-
- PrintRelDirective(true);
- O << MAI->getPersonalityPrefix();
- Asm->EmitExternalGlobal((const GlobalVariable *)(Personality));
- O << MAI->getPersonalitySuffix();
- if (strcmp(MAI->getPersonalitySuffix(), "+4@GOTPCREL"))
- O << "-" << MAI->getPCSymbol();
- Asm->EOL("Personality");
-
- Encoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
- Asm->EmitInt8(Encoding);
- Asm->EOL("LSDA Encoding", Encoding);
-
- Encoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
- Asm->EmitInt8(Encoding);
- Asm->EOL("FDE Encoding", Encoding);
- } else {
- Asm->EmitULEB128Bytes(1);
- Asm->EOL("Augmentation Size");
-
- unsigned Encoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
- Asm->EmitInt8(Encoding);
- Asm->EOL("FDE Encoding", Encoding);
- }
-
- // Indicate locations of general callee saved registers in frame.
- std::vector<MachineMove> Moves;
- RI->getInitialFrameState(Moves);
- EmitFrameMoves(NULL, 0, Moves, true);
-
- // On Darwin the linker honors the alignment of eh_frame, which means it must
- // be 8-byte on 64-bit targets to match what gcc does. Otherwise you get
- // holes which confuse readers of eh_frame.
- Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
- 0, 0, false);
- EmitLabel("eh_frame_common_end", Index);
-
- Asm->EOL();
-}
-
-/// EmitFDE - Emit the Frame Description Entry (FDE) for the function.
-void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
- assert(!EHFrameInfo.function->hasAvailableExternallyLinkage() &&
- "Should not emit 'available externally' functions at all");
-
- const Function *TheFunc = EHFrameInfo.function;
-
- Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering().getEHFrameSection());
-
- // Externally visible entry into the functions eh frame info. If the
- // corresponding function is static, this should not be externally visible.
- if (!TheFunc->hasLocalLinkage())
- if (const char *GlobalEHDirective = MAI->getGlobalEHDirective())
- O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
-
- // If corresponding function is weak definition, this should be too.
- if (TheFunc->isWeakForLinker() && MAI->getWeakDefDirective())
- O << MAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
-
- // If there are no calls then you can't unwind. This may mean we can omit the
- // EH Frame, but some environments do not handle weak absolute symbols. If
- // UnwindTablesMandatory is set we cannot do this optimization; the unwind
- // info is to be available for non-EH uses.
- if (!EHFrameInfo.hasCalls && !UnwindTablesMandatory &&
- (!TheFunc->isWeakForLinker() ||
- !MAI->getWeakDefDirective() ||
- MAI->getSupportsWeakOmittedEHFrame())) {
- O << EHFrameInfo.FnName << " = 0\n";
- // This name has no connection to the function, so it might get
- // dead-stripped when the function is not, erroneously. Prohibit
- // dead-stripping unconditionally.
- if (const char *UsedDirective = MAI->getUsedDirective())
- O << UsedDirective << EHFrameInfo.FnName << "\n\n";
- } else {
- O << EHFrameInfo.FnName << ":\n";
-
- // EH frame header.
- EmitDifference("eh_frame_end", EHFrameInfo.Number,
- "eh_frame_begin", EHFrameInfo.Number, true);
- Asm->EOL("Length of Frame Information Entry");
-
- EmitLabel("eh_frame_begin", EHFrameInfo.Number);
-
- EmitSectionOffset("eh_frame_begin", "eh_frame_common",
- EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
- true, true, false);
-
- Asm->EOL("FDE CIE offset");
-
- EmitReference("eh_func_begin", EHFrameInfo.Number, true, true);
- Asm->EOL("FDE initial location");
- EmitDifference("eh_func_end", EHFrameInfo.Number,
- "eh_func_begin", EHFrameInfo.Number, true);
- Asm->EOL("FDE address range");
+DwarfException::DwarfException(AsmPrinter *A)
+ : Asm(A), MMI(Asm->MMI) {}
- // If there is a personality and landing pads then point to the language
- // specific data area in the exception table.
- if (MMI->getPersonalities()[0] != NULL) {
- Asm->EmitULEB128Bytes(4);
- Asm->EOL("Augmentation size");
-
- if (EHFrameInfo.hasLandingPads)
- EmitReference("exception", EHFrameInfo.Number, true, true);
- else
- Asm->EmitInt32((int)0);
- Asm->EOL("Language Specific Data Area");
- } else {
- Asm->EmitULEB128Bytes(0);
- Asm->EOL("Augmentation size");
- }
-
- // Indicate locations of function specific callee saved registers in frame.
- EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves,
- true);
-
- // On Darwin the linker honors the alignment of eh_frame, which means it
- // must be 8-byte on 64-bit targets to match what gcc does. Otherwise you
- // get holes which confuse readers of eh_frame.
- Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
- 0, 0, false);
- EmitLabel("eh_frame_end", EHFrameInfo.Number);
-
- // If the function is marked used, this table should be also. We cannot
- // make the mark unconditional in this case, since retaining the table also
- // retains the function in this case, and there is code around that depends
- // on unused functions (calling undefined externals) being dead-stripped to
- // link correctly. Yes, there really is.
- if (MMI->isUsedFunction(EHFrameInfo.function))
- if (const char *UsedDirective = MAI->getUsedDirective())
- O << UsedDirective << EHFrameInfo.FnName << "\n\n";
- }
-
- Asm->EOL();
-}
+DwarfException::~DwarfException() {}
/// SharedTypeIds - How many leading type ids two landing pads have in common.
unsigned DwarfException::SharedTypeIds(const LandingPadInfo *L,
I = LandingPads.begin(), E = LandingPads.end(); I != E; ++I) {
const LandingPadInfo *LPI = *I;
const std::vector<int> &TypeIds = LPI->TypeIds;
- const unsigned NumShared = PrevLPI ? SharedTypeIds(LPI, PrevLPI) : 0;
+ unsigned NumShared = PrevLPI ? SharedTypeIds(LPI, PrevLPI) : 0;
unsigned SizeSiteActions = 0;
if (NumShared < TypeIds.size()) {
unsigned SizeAction = 0;
- ActionEntry *PrevAction = 0;
+ unsigned PrevAction = (unsigned)-1;
if (NumShared) {
- const unsigned SizePrevIds = PrevLPI->TypeIds.size();
+ unsigned SizePrevIds = PrevLPI->TypeIds.size();
assert(Actions.size());
- PrevAction = &Actions.back();
- SizeAction = MCAsmInfo::getSLEB128Size(PrevAction->NextAction) +
- MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
+ 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(PrevAction->ValueForTypeID);
- SizeAction += -PrevAction->NextAction;
- PrevAction = PrevAction->Previous;
+ MCAsmInfo::getSLEB128Size(Actions[PrevAction].ValueForTypeID);
+ SizeAction += -Actions[PrevAction].NextAction;
+ PrevAction = Actions[PrevAction].Previous;
}
}
ActionEntry Action = { ValueForTypeID, NextAction, PrevAction };
Actions.push_back(Action);
- PrevAction = &Actions.back();
+ PrevAction = Actions.size() - 1;
}
// Record the first action of the landing pad site.
// Information used when created the call-site table. The action record
// field of the call site record is the offset of the first associated
// action record, relative to the start of the actions table. This value is
- // biased by 1 (1 in dicating the start of the actions table), and 0
+ // biased by 1 (1 indicating the start of the actions table), and 0
// indicates that there are no actions.
FirstActions.push_back(FirstAction);
return SizeActions;
}
+/// CallToNoUnwindFunction - Return `true' if this is a call to a function
+/// marked `nounwind'. Return `false' otherwise.
+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) {
+ // Be conservative. If we have more than one function operand for this
+ // call, then we can't make the assumption that it's the callee and
+ // not a parameter to the call.
+ //
+ // FIXME: Determine if there's a way to say that `F' is the callee or
+ // parameter.
+ MarkedNoUnwind = false;
+ break;
+ }
+
+ MarkedNoUnwind = F->doesNotThrow();
+ SawFunc = true;
+ }
+
+ return MarkedNoUnwind;
+}
+
/// ComputeCallSiteTable - Compute the call-site table. The entry for an invoke
/// has a try-range containing the call, a non-zero landing pad, and an
/// appropriate action. The entry for an ordinary call has a try-range
const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
const SmallVectorImpl<unsigned> &FirstActions) {
// The end label of the previous invoke or nounwind try-range.
- unsigned LastLabel = 0;
+ MCSymbol *LastLabel = 0;
// Whether there is a potentially throwing instruction (currently this means
// an ordinary call) between the end of the previous try-range and now.
bool PreviousIsInvoke = false;
// Visit all instructions in order of address.
- for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
+ 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()) {
- SawPotentiallyThrowing |= MI->getDesc().isCall();
+ if (MI->isCall())
+ SawPotentiallyThrowing |= !CallToNoUnwindFunction(MI);
continue;
}
- unsigned BeginLabel = MI->getOperand(0).getImm();
- assert(BeginLabel && "Invalid label!");
-
// End of the previous try-range?
+ MCSymbol *BeginLabel = MI->getOperand(0).getMCSymbol();
if (BeginLabel == LastLabel)
SawPotentiallyThrowing = false;
// Beginning of a new try-range?
- RangeMapType::iterator L = PadMap.find(BeginLabel);
+ RangeMapType::const_iterator L = PadMap.find(BeginLabel);
if (L == PadMap.end())
// Nope, it was just some random label.
continue;
// instruction between the previous try-range and this one may throw,
// create a call-site entry with no landing pad for the region between the
// try-ranges.
- if (SawPotentiallyThrowing &&
- MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf) {
+ 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) {
+ if (!LandingPad->LandingPadLabel) {
+ // Create a gap.
+ PreviousIsInvoke = false;
+ } else {
// This try-range is for an invoke.
CallSiteEntry Site = {
BeginLabel,
FirstActions[P.PadIndex]
};
- // Try to merge with the previous call-site.
- if (PreviousIsInvoke) {
+ // Try to merge with the previous call-site. SJLJ doesn't do this
+ if (PreviousIsInvoke && Asm->MAI->isExceptionHandlingDwarf()) {
CallSiteEntry &Prev = CallSites.back();
if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
// Extend the range of the previous entry.
}
// Otherwise, create a new call-site.
- CallSites.push_back(Site);
+ if (Asm->MAI->isExceptionHandlingDwarf())
+ CallSites.push_back(Site);
+ else {
+ // SjLj EH must maintain the call sites in the order assigned
+ // to them by the SjLjPrepare pass.
+ unsigned SiteNo = MMI->getCallSiteBeginLabel(BeginLabel);
+ if (CallSites.size() < SiteNo)
+ CallSites.resize(SiteNo);
+ CallSites[SiteNo - 1] = Site;
+ }
PreviousIsInvoke = true;
- } else {
- // Create a gap.
- PreviousIsInvoke = false;
}
}
}
// If some instruction between the previous try-range and the end of the
// function may throw, create a call-site entry with no landing pad for the
// region following the try-range.
- if (SawPotentiallyThrowing &&
- MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf) {
+ if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) {
CallSiteEntry Site = { LastLabel, 0, 0, 0 };
CallSites.push_back(Site);
}
/// The general organization of the table is complex, but the basic concepts are
/// easy. First there is a header which describes the location and organization
/// of the three components that follow.
-///
+///
/// 1. The landing pad site information describes the range of code covered by
/// the try. In our case it's an accumulation of the ranges covered by the
/// invokes in the try. There is also a reference to the landing pad that
/// site, each type ID is checked for a match to the current exception. If
/// it matches then the exception and type id are passed on to the landing
/// pad. Otherwise the next action is looked up. This chain is terminated
-/// with a next action of zero. If no type id is found the the frame is
+/// with a next action of zero. If no type id is found then the frame is
/// unwound and handling continues.
/// 3. Type ID table contains references to all the C++ typeinfo for all
-/// catches in the function. This tables is reversed indexed base 1.
+/// catches in the function. This tables is reverse indexed base 1.
void DwarfException::EmitExceptionTable() {
- const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
+ const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
- if (PadInfos.empty()) return;
// Sort the landing pads in order of their type ids. This is used to fold
// duplicate actions.
// landing pad site.
SmallVector<ActionEntry, 32> Actions;
SmallVector<unsigned, 64> FirstActions;
- unsigned SizeActions = ComputeActionsTable(LandingPads, Actions, FirstActions);
+ unsigned SizeActions=ComputeActionsTable(LandingPads, Actions, FirstActions);
// Invokes and nounwind calls have entries in PadMap (due to being bracketed
// by try-range labels when lowered). Ordinary calls do not, so appropriate
- // try-ranges for them need be deduced when using Dwarf exception handling.
+ // try-ranges for them need be deduced when using DWARF exception handling.
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) {
- unsigned BeginLabel = LandingPad->BeginLabels[j];
+ MCSymbol *BeginLabel = LandingPad->BeginLabels[j];
assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
PadRange P = { i, j };
PadMap[BeginLabel] = P;
// Final tallies.
// Call sites.
- const unsigned SiteStartSize = sizeof(int32_t); // DW_EH_PE_udata4
- const unsigned SiteLengthSize = sizeof(int32_t); // DW_EH_PE_udata4
- const unsigned LandingPadSize = sizeof(int32_t); // DW_EH_PE_udata4
- unsigned SizeSites;
-
- bool HaveTTData = (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj)
- ? (!TypeInfos.empty() || !FilterIds.empty()) : true;
-
+ 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; // dwarf::DW_EH_PE_udata4
+ unsigned SiteLengthSize = 4; // dwarf::DW_EH_PE_udata4
+ unsigned LandingPadSize = 4; // dwarf::DW_EH_PE_udata4
+ CallSiteTableLength =
+ CallSites.size() * (SiteStartSize + SiteLengthSize + LandingPadSize);
+ }
- if (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- SizeSites = 0;
- } else
- SizeSites = CallSites.size() *
- (SiteStartSize + SiteLengthSize + LandingPadSize);
for (unsigned i = 0, e = CallSites.size(); i < e; ++i) {
- SizeSites += MCAsmInfo::getULEB128Size(CallSites[i].Action);
- if (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj)
- SizeSites += MCAsmInfo::getULEB128Size(i);
+ CallSiteTableLength += MCAsmInfo::getULEB128Size(CallSites[i].Action);
+ if (IsSJLJ)
+ CallSiteTableLength += MCAsmInfo::getULEB128Size(i);
}
- // Type infos.
- const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
- unsigned SizeTypes = TypeInfos.size() * TypeInfoSize;
- unsigned TypeOffset = sizeof(int8_t) + // Call site format
- MCAsmInfo::getULEB128Size(SizeSites) + // Call-site table length
- SizeSites + SizeActions + SizeTypes;
-
- unsigned TotalSize = sizeof(int8_t) + // LPStart format
- sizeof(int8_t) + // TType format
- (HaveTTData ?
- MCAsmInfo::getULEB128Size(TypeOffset) : 0) + // TType base offset
- TypeOffset;
-
- unsigned SizeAlign = (4 - TotalSize) & 3;
-
- // Begin the exception table.
+ // Type infos.
const MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection();
- Asm->OutStreamer.SwitchSection(LSDASection);
- Asm->EmitAlignment(2, 0, 0, false);
- O << "GCC_except_table" << SubprogramCount << ":\n";
-
- for (unsigned i = 0; i != SizeAlign; ++i) {
- Asm->EmitInt8(0);
- Asm->EOL("Padding");
- }
-
- EmitLabel("exception", SubprogramCount);
- if (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- std::string SjLjName = "_lsda_";
- SjLjName += MF->getFunction()->getName().str();
- EmitLabel(SjLjName.c_str(), 0);
- }
+ unsigned TTypeEncoding;
+ unsigned TypeFormatSize;
- // Emit the header.
- unsigned Encoding = dwarf::DW_EH_PE_omit;
- Asm->EmitInt8(Encoding);
- Asm->EOL("@LPStart format", Encoding);
-
-#if 0
- if (TypeInfos.empty() && FilterIds.empty()) {
- // If there are no typeinfos or filters, there is nothing to emit, optimize
- // by specifying the "omit" encoding.
- Encoding = dwarf::DW_EH_PE_omit;
- Asm->EmitInt8(Encoding);
- Asm->EOL("@TType format", Encoding);
+ if (!HaveTTData) {
+ // For SjLj exceptions, if there is no TypeInfo, then we just explicitly say
+ // that we're omitting that bit.
+ TTypeEncoding = dwarf::DW_EH_PE_omit;
+ // dwarf::DW_EH_PE_absptr
+ TypeFormatSize = Asm->getDataLayout().getPointerSize();
} else {
// Okay, we have actual filters or typeinfos to emit. As such, we need to
// pick a type encoding for them. We're about to emit a list of pointers to
// mode, this reference will require a relocation by the dynamic linker.
//
// Because of this, we have a couple of options:
+ //
// 1) If we are in -static mode, we can always use an absolute reference
// from the LSDA, because the static linker will resolve it.
+ //
// 2) Otherwise, if the LSDA section is writable, we can output the direct
// reference to the typeinfo and allow the dynamic linker to relocate
// it. Since it is in a writable section, the dynamic linker won't
// have a problem.
+ //
// 3) Finally, if we're in PIC mode and the LDSA section isn't writable,
// we need to use some form of indirection. For example, on Darwin,
// we can output a statically-relocatable reference to a dyld stub. The
// need to tell the personality function of the unwinder to indirect
// through the dyld stub.
//
- // FIXME: When this is actually implemented, we'll have to emit the stubs
+ // FIXME: When (3) is actually implemented, we'll have to emit the stubs
// somewhere. This predicate should be moved to a shared location that is
// in target-independent code.
//
- if (LSDASection->isWritable() ||
- Asm->TM.getRelocationModel() == Reloc::Static) {
- Encoding = DW_EH_PE_absptr;
- Asm->EmitInt8(Encoding);
- Asm->EOL("TType format", Encoding);
- } else {
- Encoding = DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4;
- Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
- Asm->EOL("TType format", Encoding);
- }
- Asm->EmitULEB128Bytes(TypeOffset);
- Asm->EOL("TType base offset");
+ TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
+ TypeFormatSize = Asm->GetSizeOfEncodedValue(TTypeEncoding);
}
-#else
- // For SjLj exceptions, if there is no TypeInfo, then we just explicitly
- // say that we're omitting that bit.
- // FIXME: does this apply to Dwarf also? The above #if 0 implies yes?
- if (!HaveTTData) {
- Encoding = dwarf::DW_EH_PE_omit;
- Asm->EmitInt8(Encoding);
- Asm->EOL("@TType format", Encoding);
- } else {
- Encoding = dwarf::DW_EH_PE_absptr;
- Asm->EmitInt8(Encoding);
- Asm->EOL("@TType format", Encoding);
- Asm->EmitULEB128Bytes(TypeOffset);
- Asm->EOL("@TType base offset");
+
+ // Begin the exception table.
+ // Sometimes we want not to emit the data into separate section (e.g. ARM
+ // EHABI). In this case LSDASection will be NULL.
+ if (LSDASection)
+ Asm->OutStreamer.SwitchSection(LSDASection);
+ Asm->EmitAlignment(2);
+
+ // Emit the LSDA.
+ 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()));
+
+ // Emit the LSDA header.
+ Asm->EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
+ Asm->EmitEncodingByte(TTypeEncoding, "@TType");
+
+ // The type infos need to be aligned. GCC does this by inserting padding just
+ // before the type infos. However, this changes the size of the exception
+ // table, so you need to take this into account when you output the exception
+ // table size. However, the size is output using a variable length encoding.
+ // So by increasing the size by inserting padding, you may increase the number
+ // of bytes used for writing the size. If it increases, say by one byte, then
+ // you now need to output one less byte of padding to get the type infos
+ // aligned. However this decreases the size of the exception table. This
+ // changes the value you have to output for the exception table size. Due to
+ // the variable length encoding, the number of bytes used for writing the
+ // length may decrease. If so, you then have to increase the amount of
+ // padding. And so on. If you look carefully at the GCC code you will see that
+ // it indeed does this in a loop, going on and on until the values stabilize.
+ // We chose another solution: don't output padding inside the table like GCC
+ // does, instead output it before the table.
+ unsigned SizeTypes = TypeInfos.size() * TypeFormatSize;
+ unsigned CallSiteTableLengthSize =
+ MCAsmInfo::getULEB128Size(CallSiteTableLength);
+ unsigned TTypeBaseOffset =
+ sizeof(int8_t) + // Call site format
+ CallSiteTableLengthSize + // Call site table length size
+ CallSiteTableLength + // Call site table length
+ SizeActions + // Actions size
+ SizeTypes;
+ unsigned TTypeBaseOffsetSize = MCAsmInfo::getULEB128Size(TTypeBaseOffset);
+ unsigned TotalSize =
+ sizeof(int8_t) + // LPStart format
+ sizeof(int8_t) + // TType format
+ (HaveTTData ? TTypeBaseOffsetSize : 0) + // TType base offset size
+ TTypeBaseOffset; // TType base offset
+ unsigned SizeAlign = (4 - TotalSize) & 3;
+
+ if (HaveTTData) {
+ // Account for any extra padding that will be added to the call site table
+ // length.
+ Asm->EmitULEB128(TTypeBaseOffset, "@TType base offset", SizeAlign);
+ SizeAlign = 0;
}
-#endif
- // SjLj Exception handilng
- if (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- Encoding = dwarf::DW_EH_PE_udata4;
- Asm->EmitInt8(Encoding);
- Asm->EOL("Call site format", Encoding);
- Asm->EmitULEB128Bytes(SizeSites);
- Asm->EOL("Call site table length");
+ bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
+
+ // SjLj Exception handling
+ if (IsSJLJ) {
+ Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
+
+ // Add extra padding if it wasn't added to the TType base offset.
+ Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
// Emit the landing pad site information.
unsigned idx = 0;
// Offset of the landing pad, counted in 16-byte bundles relative to the
// @LPStart address.
- Asm->EmitULEB128Bytes(idx);
- Asm->EOL("Landing pad");
+ if (VerboseAsm) {
+ Asm->OutStreamer.AddComment(">> Call Site " + Twine(idx) + " <<");
+ Asm->OutStreamer.AddComment(" On exception at call site "+Twine(idx));
+ }
+ Asm->EmitULEB128(idx);
// Offset of the first associated action record, relative to the start of
// the action table. This value is biased by 1 (1 indicates the start of
// the action table), and 0 indicates that there are no actions.
- Asm->EmitULEB128Bytes(S.Action);
- Asm->EOL("Action");
+ 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 {
// DWARF Exception handling
- assert(MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf);
+ assert(Asm->MAI->isExceptionHandlingDwarf());
// The call-site table is a list of all call sites that may throw an
// exception (including C++ 'throw' statements) in the procedure
// * The first action record for that call site.
//
// A missing entry in the call-site table indicates that a call is not
- // supposed to throw. Such calls include:
- //
- // * Calls to destructors within cleanup code. C++ semantics forbids these
- // calls to throw.
- // * Calls to intrinsic routines in the standard library which are known
- // not to throw (sin, memcpy, et al).
- //
- // If the runtime does not find the call-site entry for a given call, it
- // will call `terminate()'.
+ // supposed to throw.
// Emit the landing pad call site table.
- Encoding = dwarf::DW_EH_PE_udata4;
- Asm->EmitInt8(Encoding);
- Asm->EOL("Call site format", Encoding);
- Asm->EmitULEB128Bytes(SizeSites);
- Asm->EOL("Call site table size");
+ Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
+ // Add extra padding if it wasn't added to the TType base offset.
+ 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;
- const char *BeginTag;
- unsigned BeginNumber;
- if (!S.BeginLabel) {
- BeginTag = "eh_func_begin";
- BeginNumber = SubprogramCount;
- } else {
- BeginTag = "label";
- BeginNumber = S.BeginLabel;
- }
+ 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());
+
// Offset of the call site relative to the previous call site, counted in
// number of 16-byte bundles. The first call site is counted relative to
// the start of the procedure fragment.
- EmitSectionOffset(BeginTag, "eh_func_begin", BeginNumber, SubprogramCount,
- true, true);
- Asm->EOL("Region start");
-
- if (!S.EndLabel)
- EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
- true);
- else
- EmitDifference("label", S.EndLabel, BeginTag, BeginNumber, true);
-
- Asm->EOL("Region length");
+ 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);
// Offset of the landing pad, counted in 16-byte bundles relative to the
// @LPStart address.
- if (!S.PadLabel)
- Asm->EmitInt32(0);
- else
- EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
- true, true);
-
- Asm->EOL("Landing pad");
+ if (!S.PadLabel) {
+ if (VerboseAsm)
+ Asm->OutStreamer.AddComment(" has no landing pad");
+ Asm->OutStreamer.EmitIntValue(0, 4/*size*/, 0/*addrspace*/);
+ } else {
+ if (VerboseAsm)
+ Asm->OutStreamer.AddComment(Twine(" jumps to ") +
+ S.PadLabel->getName());
+ Asm->EmitLabelDifference(S.PadLabel, EHFuncBeginSym, 4);
+ }
// Offset of the first associated action record, relative to the start of
// the action table. This value is biased by 1 (1 indicates the start of
// the action table), and 0 indicates that there are no actions.
- Asm->EmitULEB128Bytes(S.Action);
- Asm->EOL("Action");
+ 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);
}
}
// Emit the Action Table.
+ int Entry = 0;
for (SmallVectorImpl<ActionEntry>::const_iterator
I = Actions.begin(), E = Actions.end(); I != E; ++I) {
const ActionEntry &Action = *I;
+ if (VerboseAsm) {
+ // Emit comments that decode the action table.
+ Asm->OutStreamer.AddComment(">> Action Record " + Twine(++Entry) + " <<");
+ }
+
// Type Filter
//
// Used by the runtime to match the type of the thrown exception to the
// type of the catch clauses or the types in the exception specification.
-
- Asm->EmitSLEB128Bytes(Action.ValueForTypeID);
- Asm->EOL("TypeInfo index");
+ 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);
// Action Record
//
// Self-relative signed displacement in bytes of the next action record,
// or 0 if there is no next action record.
+ 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);
+ }
- Asm->EmitSLEB128Bytes(Action.NextAction);
- Asm->EOL("Next action");
+ // Emit the Catch TypeInfos.
+ if (VerboseAsm && !TypeInfos.empty()) {
+ Asm->OutStreamer.AddComment(">> Catch TypeInfos <<");
+ Asm->OutStreamer.AddBlankLine();
+ Entry = TypeInfos.size();
}
- // Emit the Catch Clauses. The code for the catch clauses following the same
- // try is similar to a switch statement. The catch clause action record
- // informs the runtime about the type of a catch clause and about the
- // associated switch value.
- //
- // Action Record Fields:
- //
- // * Filter Value
- // Positive value, starting at 1. Index in the types table of the
- // __typeinfo for the catch-clause type. 1 is the first word preceding
- // TTBase, 2 is the second word, and so on. Used by the runtime to check
- // if the thrown exception type matches the catch-clause type. Back-end
- // generated switch statements check against this value.
- //
- // * Next
- // Signed offset, in bytes from the start of this field, to the next
- // chained action record, or zero if none.
- //
- // The order of the action records determined by the next field is the order
- // of the catch clauses as they appear in the source code, and must be kept in
- // the same order. As a result, changing the order of the catch clause would
- // change the semantics of the program.
- for (std::vector<GlobalVariable *>::const_reverse_iterator
+ for (std::vector<const GlobalVariable *>::const_reverse_iterator
I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
const GlobalVariable *GV = *I;
- PrintRelDirective();
-
- if (GV) {
- std::string GLN;
- O << Asm->getGlobalLinkName(GV, GLN);
- } else {
- O << "0";
- }
-
- Asm->EOL("TypeInfo");
+ if (VerboseAsm)
+ Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--));
+ if (GV)
+ Asm->EmitReference(GV, TTypeEncoding);
+ else
+ Asm->OutStreamer.EmitIntValue(0,Asm->GetSizeOfEncodedValue(TTypeEncoding),
+ 0);
}
- // Emit the Type Table.
+ // Emit the Exception Specifications.
+ 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;
- Asm->EmitULEB128Bytes(TypeID);
- Asm->EOL("Filter TypeInfo index");
+ if (VerboseAsm) {
+ --Entry;
+ if (TypeID != 0)
+ Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry));
+ }
+
+ Asm->EmitULEB128(TypeID);
}
- Asm->EmitAlignment(2, 0, 0, false);
+ Asm->EmitAlignment(2);
}
/// EndModule - Emit all exception information that should come after the
/// content.
void DwarfException::EndModule() {
- if (MAI->getExceptionHandlingType() != ExceptionHandling::Dwarf)
- return;
- if (TimePassesIsEnabled)
- ExceptionTimer->startTimer();
-
- if (shouldEmitMovesModule || shouldEmitTableModule) {
- const std::vector<Function *> Personalities = MMI->getPersonalities();
- for (unsigned i = 0; i < Personalities.size(); ++i)
- EmitCIE(Personalities[i], i);
-
- for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
- E = EHFrames.end(); I != E; ++I)
- EmitFDE(*I);
- }
-
- if (TimePassesIsEnabled)
- ExceptionTimer->stopTimer();
+ llvm_unreachable("Should be implemented");
}
-/// BeginFunction - Gather pre-function exception information. Assumes being
-/// emitted immediately after the function entry point.
-void DwarfException::BeginFunction(MachineFunction *MF) {
- if (TimePassesIsEnabled)
- ExceptionTimer->startTimer();
-
- this->MF = MF;
- shouldEmitTable = shouldEmitMoves = false;
-
- if (MMI && MAI->doesSupportExceptionHandling()) {
- // Map all labels and get rid of any dead landing pads.
- MMI->TidyLandingPads();
-
- // If any landing pads survive, we need an EH table.
- if (MMI->getLandingPads().size())
- shouldEmitTable = true;
-
- // See if we need frame move info.
- if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
- shouldEmitMoves = true;
-
- if (shouldEmitMoves || shouldEmitTable)
- // Assumes in correct section after the entry point.
- EmitLabel("eh_func_begin", ++SubprogramCount);
- }
-
- shouldEmitTableModule |= shouldEmitTable;
- shouldEmitMovesModule |= shouldEmitMoves;
-
- if (TimePassesIsEnabled)
- ExceptionTimer->stopTimer();
+/// BeginFunction - Gather pre-function exception information. Assumes it's
+/// being emitted immediately after the function entry point.
+void DwarfException::BeginFunction(const MachineFunction *MF) {
+ llvm_unreachable("Should be implemented");
}
/// EndFunction - Gather and emit post-function exception information.
///
void DwarfException::EndFunction() {
- if (TimePassesIsEnabled)
- ExceptionTimer->startTimer();
-
- if (shouldEmitMoves || shouldEmitTable) {
- EmitLabel("eh_func_end", SubprogramCount);
- EmitExceptionTable();
-
- // Save EH frame information
- EHFrames.push_back(
- FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
- SubprogramCount,
- MMI->getPersonalityIndex(),
- MF->getFrameInfo()->hasCalls(),
- !MMI->getLandingPads().empty(),
- MMI->getFrameMoves(),
- MF->getFunction()));
- }
-
- if (TimePassesIsEnabled)
- ExceptionTimer->stopTimer();
+ llvm_unreachable("Should be implemented");
}
projects / oota-llvm.git / blobdiff