//
//===----------------------------------------------------------------------===//
//
-// This file contains support for writing dwarf exception info into asm files.
+// This file contains support for writing DWARF exception info into asm files.
//
//===----------------------------------------------------------------------===//
#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/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/Target/TargetData.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/Dwarf.h"
-#include "llvm/Support/Mangler.h"
+#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/Timer.h"
-#include "llvm/Support/raw_ostream.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),
+ : DwarfPrinter(OS, A, T), shouldEmitTable(false),shouldEmitMoves(false),
shouldEmitTableModule(false), shouldEmitMovesModule(false),
ExceptionTimer(0) {
if (TimePassesIsEnabled)
- ExceptionTimer = new Timer("Dwarf Exception Writer",
- getDwarfTimerGroup());
+ ExceptionTimer = new Timer("DWARF Exception Writer");
}
DwarfException::~DwarfException() {
/// 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) {
+void DwarfException::EmitCIE(const Function *PersonalityFn, 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();
+ const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
- O << "EH_frame" << Index << ":\n";
- EmitLabel("section_eh_frame", Index);
+ // Begin eh frame section.
+ Asm->OutStreamer.SwitchSection(TLOF.getEHFrameSection());
+
+ MCSymbol *EHFrameSym;
+ if (TLOF.isFunctionEHFrameSymbolPrivate())
+ EHFrameSym = getDWLabel("EH_frame", Index);
+ else
+ EHFrameSym = Asm->OutContext.GetOrCreateSymbol(Twine("EH_frame") +
+ Twine(Index));
+ Asm->OutStreamer.EmitLabel(EHFrameSym);
+
+ Asm->OutStreamer.EmitLabel(getDWLabel("section_eh_frame", Index));
// Define base labels.
- EmitLabel("eh_frame_common", Index);
+ Asm->OutStreamer.EmitLabel(getDWLabel("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");
+ Asm->OutStreamer.AddComment("Length of Common Information Entry");
+ EmitDifference(getDWLabel("eh_frame_common_end", Index),
+ getDWLabel("eh_frame_common_begin", Index), true);
// 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");
+ Asm->OutStreamer.EmitLabel(getDWLabel("eh_frame_common_begin", Index));
+ Asm->OutStreamer.AddComment("CIE Identifier Tag");
+ Asm->OutStreamer.EmitIntValue(0, 4/*size*/, 0/*addrspace*/);
+ Asm->OutStreamer.AddComment("DW_CIE_VERSION");
+ Asm->OutStreamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1/*size*/, 0/*addr*/);
// The personality presence indicates that language specific information will
- // show up in the eh frame.
- Asm->EmitString(Personality ? "zPLR" : "zR");
- Asm->EOL("CIE Augmentation");
+ // show up in the eh frame. Find out how we are supposed to lower the
+ // personality function reference:
- // 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");
+ unsigned LSDAEncoding = TLOF.getLSDAEncoding();
+ unsigned FDEEncoding = TLOF.getFDEEncoding();
+ unsigned PerEncoding = TLOF.getPersonalityEncoding();
- // If there is a personality, we need to indicate the function's location.
- if (Personality) {
- Asm->EmitULEB128Bytes(7);
- Asm->EOL("Augmentation Size");
+ char Augmentation[6] = { 0 };
+ unsigned AugmentationSize = 0;
+ char *APtr = Augmentation + 1;
- if (MAI->getNeedsIndirectEncoding()) {
- Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
- dwarf::DW_EH_PE_indirect);
- Asm->EOL("Personality (pcrel sdata4 indirect)");
- } else {
- Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
- Asm->EOL("Personality (pcrel sdata4)");
- }
+ if (PersonalityFn) {
+ // There is a personality function.
+ *APtr++ = 'P';
+ AugmentationSize += 1 + SizeOfEncodedValue(PerEncoding);
+ }
+
+ if (UsesLSDA[Index]) {
+ // An LSDA pointer is in the FDE augmentation.
+ *APtr++ = 'L';
+ ++AugmentationSize;
+ }
+
+ if (FDEEncoding != dwarf::DW_EH_PE_absptr) {
+ // A non-default pointer encoding for the FDE.
+ *APtr++ = 'R';
+ ++AugmentationSize;
+ }
- 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");
+ if (APtr != Augmentation + 1)
+ Augmentation[0] = 'z';
- Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
- Asm->EOL("LSDA Encoding (pcrel sdata4)");
+ Asm->OutStreamer.AddComment("CIE Augmentation");
+ Asm->OutStreamer.EmitBytes(StringRef(Augmentation, strlen(Augmentation)+1),0);
- Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
- Asm->EOL("FDE Encoding (pcrel sdata4)");
- } else {
- Asm->EmitULEB128Bytes(1);
- Asm->EOL("Augmentation Size");
+ // Round out reader.
+ EmitULEB128(1, "CIE Code Alignment Factor");
+ EmitSLEB128(stackGrowth, "CIE Data Alignment Factor");
+ Asm->OutStreamer.AddComment("CIE Return Address Column");
+ Asm->EmitInt8(RI->getDwarfRegNum(RI->getRARegister(), true));
+
+ if (Augmentation[0]) {
+ EmitULEB128(AugmentationSize, "Augmentation Size");
- Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
- Asm->EOL("FDE Encoding (pcrel sdata4)");
+ // If there is a personality, we need to indicate the function's location.
+ if (PersonalityFn) {
+ EmitEncodingByte(PerEncoding, "Personality");
+ Asm->OutStreamer.AddComment("Personality");
+ EmitReference(PersonalityFn, PerEncoding);
+ }
+ if (UsesLSDA[Index])
+ EmitEncodingByte(LSDAEncoding, "LSDA");
+ if (FDEEncoding != dwarf::DW_EH_PE_absptr)
+ EmitEncodingByte(FDEEncoding, "FDE");
}
// Indicate locations of general callee saved registers in frame.
std::vector<MachineMove> Moves;
RI->getInitialFrameState(Moves);
- EmitFrameMoves(NULL, 0, Moves, true);
+ EmitFrameMoves(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();
+ Asm->EmitAlignment(TD->getPointerSize() == 4 ? 2 : 3, 0, 0, false);
+ Asm->OutStreamer.EmitLabel(getDWLabel("eh_frame_common_end", Index));
}
/// EmitFDE - Emit the Frame Description Entry (FDE) for the function.
"Should not emit 'available externally' functions at all");
const Function *TheFunc = EHFrameInfo.function;
+ const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+
+ unsigned LSDAEncoding = TLOF.getLSDAEncoding();
+ unsigned FDEEncoding = TLOF.getFDEEncoding();
- Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering().getEHFrameSection());
+ Asm->OutStreamer.SwitchSection(TLOF.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 (!TheFunc->hasLocalLinkage() && TLOF.isFunctionEHSymbolGlobal())
+ Asm->OutStreamer.EmitSymbolAttribute(EHFrameInfo.FunctionEHSym,MCSA_Global);
// If corresponding function is weak definition, this should be too.
if (TheFunc->isWeakForLinker() && MAI->getWeakDefDirective())
- O << MAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
+ Asm->OutStreamer.EmitSymbolAttribute(EHFrameInfo.FunctionEHSym,
+ MCSA_WeakDefinition);
+
+ // If corresponding function is hidden, this should be too.
+ if (TheFunc->hasHiddenVisibility())
+ if (MCSymbolAttr HiddenAttr = MAI->getHiddenVisibilityAttr())
+ Asm->OutStreamer.EmitSymbolAttribute(EHFrameInfo.FunctionEHSym,
+ HiddenAttr);
// 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
if (!EHFrameInfo.hasCalls && !UnwindTablesMandatory &&
(!TheFunc->isWeakForLinker() ||
!MAI->getWeakDefDirective() ||
- MAI->getSupportsWeakOmittedEHFrame())) {
- O << EHFrameInfo.FnName << " = 0\n";
+ TLOF.getSupportsWeakOmittedEHFrame())) {
+ Asm->OutStreamer.EmitAssignment(EHFrameInfo.FunctionEHSym,
+ MCConstantExpr::Create(0, Asm->OutContext));
// 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";
+ if (MAI->hasNoDeadStrip())
+ Asm->OutStreamer.EmitSymbolAttribute(EHFrameInfo.FunctionEHSym,
+ MCSA_NoDeadStrip);
} else {
- O << EHFrameInfo.FnName << ":\n";
+ Asm->OutStreamer.EmitLabel(EHFrameInfo.FunctionEHSym);
// EH frame header.
- EmitDifference("eh_frame_end", EHFrameInfo.Number,
- "eh_frame_begin", EHFrameInfo.Number, true);
- Asm->EOL("Length of Frame Information Entry");
+ Asm->OutStreamer.AddComment("Length of Frame Information Entry");
+ EmitDifference(getDWLabel("eh_frame_end", EHFrameInfo.Number),
+ getDWLabel("eh_frame_begin", EHFrameInfo.Number),
+ true);
- EmitLabel("eh_frame_begin", EHFrameInfo.Number);
+ Asm->OutStreamer.EmitLabel(getDWLabel("eh_frame_begin",EHFrameInfo.Number));
- EmitSectionOffset("eh_frame_begin", "eh_frame_common",
- EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
- true, true, false);
+ Asm->OutStreamer.AddComment("FDE CIE offset");
+ EmitSectionOffset(getDWLabel("eh_frame_begin", EHFrameInfo.Number),
+ getDWLabel("eh_frame_common",
+ EHFrameInfo.PersonalityIndex),
+ true, true);
- Asm->EOL("FDE CIE offset");
+ MCSymbol *EHFuncBeginSym = getDWLabel("eh_func_begin", EHFrameInfo.Number);
- 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");
+ Asm->OutStreamer.AddComment("FDE initial location");
+ EmitReference(EHFuncBeginSym, FDEEncoding);
+
+ Asm->OutStreamer.AddComment("FDE address range");
+ EmitDifference(getDWLabel("eh_func_end", EHFrameInfo.Number),EHFuncBeginSym,
+ SizeOfEncodedValue(FDEEncoding) == 4);
// 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) {
- bool is4Byte = TD->getPointerSize() == sizeof(int32_t);
-
- Asm->EmitULEB128Bytes(is4Byte ? 4 : 8);
- Asm->EOL("Augmentation size");
+ unsigned Size = SizeOfEncodedValue(LSDAEncoding);
+ EmitULEB128(Size, "Augmentation size");
+ Asm->OutStreamer.AddComment("Language Specific Data Area");
if (EHFrameInfo.hasLandingPads)
- EmitReference("exception", EHFrameInfo.Number, true, false);
- else {
- if (is4Byte)
- Asm->EmitInt32((int)0);
- else
- Asm->EmitInt64((int)0);
- }
- Asm->EOL("Language Specific Data Area");
+ EmitReference(getDWLabel("exception", EHFrameInfo.Number),LSDAEncoding);
+ else
+ Asm->OutStreamer.EmitIntValue(0, Size/*size*/, 0/*addrspace*/);
+
} else {
- Asm->EmitULEB128Bytes(0);
- Asm->EOL("Augmentation size");
+ EmitULEB128(0, "Augmentation size");
}
// Indicate locations of function specific callee saved registers in frame.
- EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves,
- true);
+ EmitFrameMoves(EHFuncBeginSym, 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);
+ Asm->OutStreamer.EmitLabel(getDWLabel("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
// 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";
+ if (MAI->hasNoDeadStrip())
+ Asm->OutStreamer.EmitSymbolAttribute(EHFrameInfo.FunctionEHSym,
+ MCSA_NoDeadStrip);
}
-
- Asm->EOL();
+ Asm->OutStreamer.AddBlankLine();
}
/// SharedTypeIds - How many leading type ids two landing pads have in common.
if (NumShared < TypeIds.size()) {
unsigned SizeAction = 0;
- ActionEntry *PrevAction = 0;
+ unsigned PrevAction = (unsigned)-1;
if (NumShared) {
const 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->getDesc().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()) {
+ if (Function *F = dyn_cast<Function>(MO.getGlobal())) {
+ 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.
for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
MI != E; ++MI) {
if (!MI->isLabel()) {
- SawPotentiallyThrowing |= MI->getDesc().isCall();
+ if (MI->getDesc().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;
}
// Otherwise, create a new call-site.
- CallSites.push_back(Site);
+ if (MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf)
+ 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.
/// 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<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;
-
-
- if (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- SizeSites = 0;
- } else
- SizeSites = CallSites.size() *
+ const unsigned SiteStartSize = SizeOfEncodedValue(dwarf::DW_EH_PE_udata4);
+ const unsigned SiteLengthSize = SizeOfEncodedValue(dwarf::DW_EH_PE_udata4);
+ const unsigned LandingPadSize = SizeOfEncodedValue(dwarf::DW_EH_PE_udata4);
+ bool IsSJLJ = MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
+ bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true;
+ unsigned CallSiteTableLength;
+
+ if (IsSJLJ)
+ CallSiteTableLength = 0;
+ else
+ CallSiteTableLength = 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";
+ unsigned TTypeEncoding;
+ unsigned TypeFormatSize;
- for (unsigned i = 0; i != SizeAlign; ++i) {
- Asm->EmitInt8(0);
- Asm->EOL("Padding");
- }
-
- EmitLabel("exception", SubprogramCount);
- if (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- SmallString<16> LSDAName;
- raw_svector_ostream(LSDAName) << MAI->getPrivateGlobalPrefix() <<
- "_LSDA_" << Asm->getFunctionNumber();
- O << LSDAName.str() << ":\n";
- }
-
- // Emit the header.
- Asm->EmitInt8(dwarf::DW_EH_PE_omit);
- Asm->EOL("@LPStart format (DW_EH_PE_omit)");
-
-#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.
- Asm->EmitInt8(dwarf::DW_EH_PE_omit);
- Asm->EOL("@TType format (DW_EH_PE_omit)");
+ 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;
+ TypeFormatSize = SizeOfEncodedValue(dwarf::DW_EH_PE_absptr);
} 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) {
- Asm->EmitInt8(DW_EH_PE_absptr);
- Asm->EOL("TType format (DW_EH_PE_absptr)");
- } else {
- Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
- Asm->EOL("TType format (DW_EH_PE_pcrel | DW_EH_PE_indirect"
- " | DW_EH_PE_sdata4)");
- }
- Asm->EmitULEB128Bytes(TypeOffset);
- Asm->EOL("TType base offset");
+ TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
+ TypeFormatSize = SizeOfEncodedValue(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) {
- Asm->EmitInt8(dwarf::DW_EH_PE_omit);
- Asm->EOL("@TType format (DW_EH_PE_omit)");
- } else {
- Asm->EmitInt8(dwarf::DW_EH_PE_absptr);
- Asm->EOL("@TType format (DW_EH_PE_absptr)");
- Asm->EmitULEB128Bytes(TypeOffset);
- Asm->EOL("@TType base offset");
+
+ // Begin the exception table.
+ Asm->OutStreamer.SwitchSection(LSDASection);
+ Asm->EmitAlignment(2, 0, 0, false);
+
+ // Emit the LSDA.
+ MCSymbol *GCCETSym =
+ Asm->OutContext.GetOrCreateSymbol(Twine("GCC_except_table")+
+ Twine(SubprogramCount));
+ Asm->OutStreamer.EmitLabel(GCCETSym);
+ Asm->OutStreamer.EmitLabel(getDWLabel("exception", SubprogramCount));
+
+ if (IsSJLJ)
+ Asm->OutStreamer.EmitLabel(getDWLabel("_LSDA_", Asm->getFunctionNumber()));
+
+ // Emit the LSDA header.
+ EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
+ 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.
+ EmitULEB128(TTypeBaseOffset, "@TType base offset", SizeAlign);
+ SizeAlign = 0;
}
-#endif
- // SjLj Exception handilng
- if (MAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- Asm->EmitInt8(dwarf::DW_EH_PE_udata4);
- Asm->EOL("Call site format (DW_EH_PE_udata4)");
- Asm->EmitULEB128Bytes(SizeSites);
- Asm->EOL("Call site table length");
+ // SjLj Exception handling
+ if (IsSJLJ) {
+ EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
+
+ // Add extra padding if it wasn't added to the TType base offset.
+ 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");
+ EmitULEB128(idx, "Landing pad");
// 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");
+ EmitULEB128(S.Action, "Action");
}
} else {
// DWARF Exception handling
// * 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.
- Asm->EmitInt8(dwarf::DW_EH_PE_udata4);
- Asm->EOL("Call site format (DW_EH_PE_udata4)");
- Asm->EmitULEB128Bytes(SizeSites);
- Asm->EOL("Call site table size");
+ EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
+
+ // Add extra padding if it wasn't added to the TType base offset.
+ EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
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 = getDWLabel("eh_func_begin", SubprogramCount);
+
+ MCSymbol *BeginLabel = S.BeginLabel;
+ if (BeginLabel == 0)
+ BeginLabel = EHFuncBeginSym;
+ MCSymbol *EndLabel = S.EndLabel;
+ if (EndLabel == 0)
+ EndLabel = getDWLabel("eh_func_end", SubprogramCount);
+
// 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");
+ Asm->OutStreamer.AddComment("Region start");
+ EmitSectionOffset(BeginLabel, EHFuncBeginSym, true, true);
+
+ Asm->OutStreamer.AddComment("Region length");
+ EmitDifference(EndLabel, BeginLabel, true);
- if (!S.EndLabel)
- EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
- true);
- else
- EmitDifference("label", S.EndLabel, BeginTag, BeginNumber, true);
-
- Asm->EOL("Region length");
// Offset of the landing pad, counted in 16-byte bundles relative to the
// @LPStart address.
+ Asm->OutStreamer.AddComment("Landing pad");
if (!S.PadLabel)
- Asm->EmitInt32(0);
+ Asm->OutStreamer.EmitIntValue(0, 4/*size*/, 0/*addrspace*/);
else
- EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
- true, true);
-
- Asm->EOL("Landing pad");
+ EmitSectionOffset(S.PadLabel, EHFuncBeginSym, true, true);
// 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");
+ EmitULEB128(S.Action, "Action");
}
}
// Emit the Action Table.
+ if (Actions.size() != 0) {
+ Asm->OutStreamer.AddComment("-- Action Record Table --");
+ Asm->OutStreamer.AddBlankLine();
+ }
+
for (SmallVectorImpl<ActionEntry>::const_iterator
I = Actions.begin(), E = Actions.end(); I != E; ++I) {
const ActionEntry &Action = *I;
+ Asm->OutStreamer.AddComment("Action Record");
+ Asm->OutStreamer.AddBlankLine();
// 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");
+ EmitSLEB128(Action.ValueForTypeID, " TypeInfo index");
// Action Record
//
// Self-relative signed displacement in bytes of the next action record,
// or 0 if there is no next action record.
-
- Asm->EmitSLEB128Bytes(Action.NextAction);
- Asm->EOL("Next action");
+ EmitSLEB128(Action.NextAction, " Next action");
}
- // 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.
+ // Emit the Catch TypeInfos.
+ if (!TypeInfos.empty()) {
+ Asm->OutStreamer.AddComment("-- Catch TypeInfos --");
+ Asm->OutStreamer.AddBlankLine();
+ }
for (std::vector<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 << "0x0";
- }
- Asm->EOL("TypeInfo");
+ Asm->OutStreamer.AddComment("TypeInfo");
+ if (GV)
+ EmitReference(GV, TTypeEncoding);
+ else
+ Asm->OutStreamer.EmitIntValue(0, SizeOfEncodedValue(TTypeEncoding), 0);
}
- // Emit the Type Table.
+ // Emit the Exception Specifications.
+ if (!FilterIds.empty()) {
+ Asm->OutStreamer.AddComment("-- Filter IDs --");
+ Asm->OutStreamer.AddBlankLine();
+ }
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");
+ EmitULEB128(TypeID, TypeID != 0 ? "Exception specification" : 0);
}
Asm->EmitAlignment(2, 0, 0, false);
if (MAI->getExceptionHandlingType() != ExceptionHandling::Dwarf)
return;
+ if (!shouldEmitMovesModule && !shouldEmitTableModule)
+ return;
+
if (TimePassesIsEnabled)
ExceptionTimer->startTimer();
- if (shouldEmitMovesModule || shouldEmitTableModule) {
- const std::vector<Function *> Personalities = MMI->getPersonalities();
+ const std::vector<Function *> Personalities = MMI->getPersonalities();
- for (unsigned i = 0, e = Personalities.size(); i < e; ++i)
- EmitCIE(Personalities[i], i);
+ for (unsigned I = 0, E = Personalities.size(); I < E; ++I)
+ EmitCIE(Personalities[I], I);
- for (std::vector<FunctionEHFrameInfo>::iterator
- I = EHFrames.begin(), E = EHFrames.end(); I != E; ++I)
- EmitFDE(*I);
- }
+ for (std::vector<FunctionEHFrameInfo>::iterator
+ I = EHFrames.begin(), E = EHFrames.end(); I != E; ++I)
+ EmitFDE(*I);
if (TimePassesIsEnabled)
ExceptionTimer->stopTimer();
}
-/// BeginFunction - Gather pre-function exception information. Assumes being
-/// emitted immediately after the function entry point.
-void DwarfException::BeginFunction(MachineFunction *MF) {
+/// BeginFunction - Gather pre-function exception information. Assumes it's
+/// being emitted immediately after the function entry point.
+void DwarfException::BeginFunction(const MachineFunction *MF) {
+ if (!MMI || !MAI->doesSupportExceptionHandling()) return;
+
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().empty())
- shouldEmitTable = true;
+ // If any landing pads survive, we need an EH table.
+ shouldEmitTable = !MMI->getLandingPads().empty();
- // See if we need frame move info.
- if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
- shouldEmitMoves = true;
+ // See if we need frame move info.
+ shouldEmitMoves = !MF->getFunction()->doesNotThrow() || UnwindTablesMandatory;
- if (shouldEmitMoves || shouldEmitTable)
- // Assumes in correct section after the entry point.
- EmitLabel("eh_func_begin", ++SubprogramCount);
- }
+ if (shouldEmitMoves || shouldEmitTable)
+ // Assumes in correct section after the entry point.
+ Asm->OutStreamer.EmitLabel(getDWLabel("eh_func_begin", ++SubprogramCount));
shouldEmitTableModule |= shouldEmitTable;
shouldEmitMovesModule |= shouldEmitMoves;
if (TimePassesIsEnabled)
ExceptionTimer->startTimer();
- EmitLabel("eh_func_end", SubprogramCount);
- EmitExceptionTable();
+ Asm->OutStreamer.EmitLabel(getDWLabel("eh_func_end", SubprogramCount));
+
+ // Record if this personality index uses a landing pad.
+ bool HasLandingPad = !MMI->getLandingPads().empty();
+ UsesLSDA[MMI->getPersonalityIndex()] |= HasLandingPad;
+
+ // Map all labels and get rid of any dead landing pads.
+ MMI->TidyLandingPads();
+
+ if (HasLandingPad)
+ EmitExceptionTable();
+ const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+ MCSymbol *FunctionEHSym =
+ Asm->GetSymbolWithGlobalValueBase(MF->getFunction(), ".eh",
+ TLOF.isFunctionEHFrameSymbolPrivate());
+
// Save EH frame information
- EHFrames.push_back(FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
- SubprogramCount,
+ EHFrames.push_back(FunctionEHFrameInfo(FunctionEHSym, SubprogramCount,
MMI->getPersonalityIndex(),
MF->getFrameInfo()->hasCalls(),
!MMI->getLandingPads().empty(),
projects / oota-llvm.git / blobdiff