Emits exception handling directives. More...

#include <EHStreamer.h>

Inheritance diagram for llvm::EHStreamer:

Collaboration diagram for llvm::EHStreamer:

Classes
struct	ActionEntry
	Structure describing an entry in the actions table. More...
struct	CallSiteEntry
	Structure describing an entry in the call-site table. More...
struct	PadRange
	Structure holding a try-range and the associated landing pad. More...
Public Member Functions
	EHStreamer (AsmPrinter *A)
virtual	~EHStreamer ()
void	endModule () override
	Emit all exception information that should come after the content.
void	beginFunction (const MachineFunction *MF) override
void	endFunction (const MachineFunction *) override
	Gather and emit post-function exception information.
void	setSymbolSize (const MCSymbol *Sym, uint64_t Size) override
	For symbols that have a size designated (e.g. common symbols), this tracks that size.
void	beginInstruction (const MachineInstr *MI) override
	Process beginning of an instruction.
void	endInstruction () override
	Process end of an instruction.
Protected Types
typedef DenseMap< MCSymbol *, PadRange >	RangeMapType
Protected Member Functions
unsigned	computeActionsTable (const SmallVectorImpl< const LandingPadInfo * > &LPs, SmallVectorImpl< ActionEntry > &Actions, SmallVectorImpl< unsigned > &FirstActions)
bool	callToNoUnwindFunction (const MachineInstr *MI)
void	computeCallSiteTable (SmallVectorImpl< CallSiteEntry > &CallSites, const RangeMapType &PadMap, const SmallVectorImpl< const LandingPadInfo * > &LPs, const SmallVectorImpl< unsigned > &FirstActions)
void	emitExceptionTable ()
virtual void	emitTypeInfos (unsigned TTypeEncoding)
Static Protected Member Functions
static unsigned	sharedTypeIDs (const LandingPadInfo L, const LandingPadInfo R)
	How many leading type ids two landing pads have in common.
Protected Attributes
AsmPrinter *	Asm
	Target of directive emission.
MachineModuleInfo *	MMI
	Collected machine module information.

Detailed Description

Emits exception handling directives.

Definition at line 31 of file EHStreamer.h.

Member Typedef Documentation

typedef DenseMap<MCSymbol *, PadRange> llvm::EHStreamer::RangeMapType [protected]

Definition at line 51 of file EHStreamer.h.

Constructor & Destructor Documentation

EHStreamer::EHStreamer ( AsmPrinter * A )

Definition at line 28 of file EHStreamer.cpp.

EHStreamer::~EHStreamer ( ) [virtual]

Definition at line 30 of file EHStreamer.cpp.

Member Function Documentation

void EHStreamer::beginFunction ( const MachineFunction * MF ) [override, virtual]

Gather pre-function exception information. Assumes being emitted immediately after the function entry point.

Gather pre-function exception information. Assumes it's being emitted immediately after the function entry point.

Implements llvm::AsmPrinterHandler.

Reimplemented in llvm::ARMException, llvm::DwarfCFIException, and llvm::Win64Exception.

Definition at line 699 of file EHStreamer.cpp.

References llvm_unreachable.

void llvm::EHStreamer::beginInstruction ( const MachineInstr * MI ) [inline, override, virtual]

Process beginning of an instruction.

Implements llvm::AsmPrinterHandler.

Definition at line 132 of file EHStreamer.h.

bool EHStreamer::callToNoUnwindFunction ( const MachineInstr * MI ) [protected]

Return `true' if this is a call to a function marked `nounwind'. Return `false' otherwise.

Definition at line 158 of file EHStreamer.cpp.

References llvm::Function::doesNotThrow(), llvm::dyn_cast(), F(), llvm::MachineOperand::getGlobal(), llvm::MachineInstr::getNumOperands(), llvm::MachineInstr::getOperand(), I, llvm::MachineInstr::isCall(), and llvm::MachineOperand::isGlobal().

Referenced by computeCallSiteTable().

unsigned EHStreamer::computeActionsTable	(	const SmallVectorImpl< const LandingPadInfo * > &	LandingPads,
		SmallVectorImpl< ActionEntry > &	Actions,
		SmallVectorImpl< unsigned > &	FirstActions
	)		`[protected]`

Compute the actions table and gather the first action index for each landing pad site.

Definition at line 50 of file EHStreamer.cpp.

References llvm::SmallVectorTemplateCommon< T >::begin(), llvm::SmallVectorTemplateCommon< T >::end(), llvm::MachineModuleInfo::getFilterIds(), llvm::getSLEB128Size(), llvm::getULEB128Size(), I, MMI, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), llvm::SmallVectorImpl< T >::reserve(), sharedTypeIDs(), llvm::SmallVectorTemplateCommon< T >::size(), llvm::SmallVectorTemplateCommon< T, typename >::size(), and llvm::LandingPadInfo::TypeIds.

Referenced by emitExceptionTable().

void EHStreamer::computeCallSiteTable	(	SmallVectorImpl< CallSiteEntry > &	CallSites,
		const RangeMapType &	PadMap,
		const SmallVectorImpl< const LandingPadInfo * > &	LandingPads,
		const SmallVectorImpl< unsigned > &	FirstActions
	)		`[protected]`

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 containing the call and zero for the landing pad and the action. Calls marked 'nounwind' have no entry and must not be contained in the try-range of any entry - they form gaps in the table. Entries must be ordered by try-range address.

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 containing the call and zero for the landing pad and the action. Calls marked 'nounwind' have no entry and must not be contained in the try-range of any entry - they form gaps in the table. Entries must be ordered by try-range address.

Definition at line 197 of file EHStreamer.cpp.

References llvm::EHStreamer::CallSiteEntry::Action, Asm, llvm::SmallVectorTemplateCommon< T >::back(), llvm::LandingPadInfo::BeginLabels, callToNoUnwindFunction(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT >::end(), llvm::EHStreamer::CallSiteEntry::EndLabel, llvm::LandingPadInfo::EndLabels, llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT >::find(), llvm::MachineModuleInfo::getCallSiteBeginLabel(), llvm::MCAsmInfo::isExceptionHandlingDwarf(), llvm::LandingPad, llvm::LandingPadInfo::LandingPadLabel, llvm::AsmPrinter::MAI, llvm::AsmPrinter::MF, llvm::AArch64CC::MI, MMI, P, llvm::EHStreamer::PadRange::PadIndex, llvm::EHStreamer::CallSiteEntry::PadLabel, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::EHStreamer::PadRange::RangeIndex, llvm::SmallVectorImpl< T >::resize(), and llvm::SmallVectorTemplateCommon< T >::size().

Referenced by emitExceptionTable().

void EHStreamer::emitExceptionTable ( ) [protected]

Emit landing pads and actions.

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 handles the exception once processed. Finally an index into the actions table. 2. The action table, in our case, is composed of pairs of type ids and next action offset. Starting with the action index from the landing pad 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 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.

Emit landing pads and actions.

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 handles the exception once processed. Finally an index into the actions table. 2. The action table, in our case, is composed of pairs of type IDs and next action offset. Starting with the action index from the landing pad 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 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 reverse indexed base 1.

Definition at line 316 of file EHStreamer.cpp.

References llvm::EHStreamer::CallSiteEntry::Action, llvm::MCStreamer::AddComment(), Asm, llvm::SmallVectorTemplateCommon< T >::begin(), llvm::EHStreamer::CallSiteEntry::BeginLabel, llvm::LandingPadInfo::BeginLabels, computeActionsTable(), computeCallSiteTable(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT >::count(), llvm::dwarf::DW_EH_PE_omit, llvm::dwarf::DW_EH_PE_udata4, llvm::AsmPrinter::EmitAlignment(), llvm::AsmPrinter::EmitEncodingByte(), llvm::MCStreamer::EmitIntValue(), llvm::MCStreamer::EmitLabel(), llvm::AsmPrinter::EmitLabelDifference(), llvm::AsmPrinter::EmitSLEB128(), emitTypeInfos(), llvm::AsmPrinter::EmitULEB128(), llvm::SmallVectorTemplateCommon< T >::end(), llvm::EHStreamer::CallSiteEntry::EndLabel, llvm::AsmPrinter::getDataLayout(), llvm::MCAsmInfo::getExceptionHandlingType(), llvm::MachineModuleInfo::getFilterIds(), llvm::AsmPrinter::getFunctionNumber(), llvm::MachineModuleInfo::getLandingPads(), llvm::MCObjectFileInfo::getLSDASection(), llvm::MCSymbol::getName(), llvm::AsmPrinter::getObjFileLowering(), llvm::MCContext::GetOrCreateSymbol(), llvm::DataLayout::getPointerSize(), llvm::AsmPrinter::GetSizeOfEncodedValue(), llvm::AsmPrinter::GetTempSymbol(), llvm::MCObjectFileInfo::getTTypeEncoding(), llvm::MachineModuleInfo::getTypeInfos(), llvm::getULEB128Size(), I, llvm::MCAsmInfo::isExceptionHandlingDwarf(), llvm::MCStreamer::isVerboseAsm(), llvm::LandingPad, llvm::AsmPrinter::MAI, MMI, N, llvm::EHStreamer::ActionEntry::NextAction, llvm::AsmPrinter::OutContext, llvm::AsmPrinter::OutStreamer, P, llvm::EHStreamer::CallSiteEntry::PadLabel, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorImpl< T >::reserve(), llvm::SmallVectorTemplateCommon< T >::size(), llvm::SmallVectorTemplateCommon< T, typename >::size(), llvm::SjLj, llvm::MCStreamer::SwitchSection(), llvm::LandingPadInfo::TypeIds, and llvm::EHStreamer::ActionEntry::ValueForTypeID.