llvm::EHStreamer Class Reference

Emits exception handling directives. More...

#include "CodeGen/AsmPrinter/EHStreamer.h"

Inheritance 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	CallSiteRange
	Structure describing a contiguous range of call-sites which reside in the same procedure fragment. More...
struct	PadRange
	Structure holding a try-range and the associated landing pad. More...

Public Member Functions
	EHStreamer (AsmPrinter *A)
	~EHStreamer () override
void	setSymbolSize (const MCSymbol *Sym, uint64_t Size) override
	For symbols that have a size designated (e.g.
void	beginInstruction (const MachineInstr *MI) override
	Process beginning of an instruction.
void	endInstruction () override
	Process end of an instruction.
Public Member Functions inherited from llvm::AsmPrinterHandler
virtual	~AsmPrinterHandler ()
	Pin vtable to this file.
virtual void	setSymbolSize (const MCSymbol *Sym, uint64_t Size)=0
	For symbols that have a size designated (e.g.
virtual void	beginModule (Module *M)
virtual void	endModule ()=0
	Emit all sections that should come after the content.
virtual void	beginFunction (const MachineFunction *MF)=0
	Gather pre-function debug information.
virtual void	markFunctionEnd ()
virtual void	endFunction (const MachineFunction *MF)=0
	Gather post-function debug information.
virtual void	beginBasicBlockSection (const MachineBasicBlock &MBB)
	Process the beginning of a new basic-block-section within a function.
virtual void	endBasicBlockSection (const MachineBasicBlock &MBB)
	Process the end of a basic-block-section within a function.
virtual void	beginFunclet (const MachineBasicBlock &MBB, MCSymbol *Sym=nullptr)
	Emit target-specific EH funclet machinery.
virtual void	endFunclet ()
virtual void	beginInstruction (const MachineInstr *MI)=0
	Process beginning of an instruction.
virtual void	endInstruction ()=0
	Process end of an instruction.

Static Public Member Functions
static bool	callToNoUnwindFunction (const MachineInstr *MI)
	Return ‘true’ if this is a call to a function marked ‘nounwind’.

Protected Types
using	RangeMapType = DenseMap< MCSymbol *, PadRange >

Protected Member Functions
void	computeActionsTable (const SmallVectorImpl< const LandingPadInfo * > &LandingPads, SmallVectorImpl< ActionEntry > &Actions, SmallVectorImpl< unsigned > &FirstActions)
	Compute the actions table and gather the first action index for each landing pad site.
void	computePadMap (const SmallVectorImpl< const LandingPadInfo * > &LandingPads, RangeMapType &PadMap)
virtual void	computeCallSiteTable (SmallVectorImpl< CallSiteEntry > &CallSites, SmallVectorImpl< CallSiteRange > &CallSiteRanges, const SmallVectorImpl< const LandingPadInfo * > &LandingPads, const SmallVectorImpl< unsigned > &FirstActions)
	Compute the call-site table and the call-site ranges.
MCSymbol *	emitExceptionTable ()
	Emit landing pads and actions.
virtual void	emitTypeInfos (unsigned TTypeEncoding, MCSymbol *TTBaseLabel)

Static Protected Member Functions
static unsigned	sharedTypeIDs (const LandingPadInfo *L, const LandingPadInfo *R)
	How many leading type ids two landing pads have in common.
static bool	isFilterEHSelector (int Selector)
static bool	isCleanupEHSelector (int Selector)
static bool	isCatchEHSelector (int Selector)

Protected Attributes
AsmPrinter *	Asm
	Target of directive emission.
MachineModuleInfo *	MMI
	Collected machine module information.

Detailed Description

Emits exception handling directives.

Definition at line 30 of file EHStreamer.h.

Member Typedef Documentation

RangeMapType

using llvm::EHStreamer::RangeMapType = DenseMap<MCSymbol *, PadRange>

protected

Definition at line 51 of file EHStreamer.h.

Constructor & Destructor Documentation

EHStreamer()

EHStreamer::EHStreamer

(

AsmPrinter *

A

)

Definition at line 37 of file EHStreamer.cpp.

~EHStreamer()

EHStreamer::~EHStreamer ( )

overridedefault

Member Function Documentation

beginInstruction()

void llvm::EHStreamer::beginInstruction ( const MachineInstr *  MI )

inlineoverridevirtual

Process beginning of an instruction.

Implements llvm::AsmPrinterHandler.

Definition at line 155 of file EHStreamer.h.

callToNoUnwindFunction()

bool EHStreamer::callToNoUnwindFunction ( const MachineInstr *  MI )

static

Return ‘true’ if this is a call to a function marked ‘nounwind’.

Return ‘false’ otherwise.

Definition at line 157 of file EHStreamer.cpp.

References assert(), F, and MI.

Referenced by computeCallSiteTable().

computeActionsTable()

void 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 52 of file EHStreamer.cpp.

References Asm, assert(), llvm::MachineFunction::getFilterIds(), llvm::getSLEB128Size(), llvm::getULEB128Size(), isFilterEHSelector(), llvm::AsmPrinter::MF, llvm::Offset, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorImpl< T >::reserve(), sharedTypeIDs(), llvm::SmallVectorBase< Size_T >::size(), and llvm::LandingPadInfo::TypeIds.

Referenced by emitExceptionTable().

computeCallSiteTable()

void EHStreamer::computeCallSiteTable ( SmallVectorImpl< CallSiteEntry > &  CallSites, SmallVectorImpl< CallSiteRange > &  CallSiteRanges, const SmallVectorImpl< const LandingPadInfo * > &  LandingPads, const SmallVectorImpl< unsigned > &  FirstActions  )

protectedvirtual

Compute the call-site table and the call-site ranges.

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. CallSiteRanges vector is only populated for Itanium exception handling.

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.

Call-sites are split into one or more call-site ranges associated with different sections of the function.

• Without -basic-block-sections, all call-sites are grouped into one call-site-range corresponding to the function section.
• With -basic-block-sections, one call-site range is created for each section, with its FragmentBeginLabel and FragmentEndLabel respectively

Reimplemented in llvm::WasmException.

Definition at line 230 of file EHStreamer.cpp.

References llvm::EHStreamer::CallSiteEntry::Action, llvm::AIX, Asm, assert(), llvm::SmallVectorTemplateCommon< T, typename >::back(), llvm::MachineFunction::back(), llvm::LandingPadInfo::BeginLabels, callToNoUnwindFunction(), computePadMap(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::EHStreamer::CallSiteEntry::EndLabel, llvm::LandingPadInfo::EndLabels, llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::find(), llvm::MachineFunction::front(), llvm::MachineFunction::getCallSiteBeginLabel(), llvm::MCAsmInfo::getExceptionHandlingType(), llvm::AsmPrinter::getFunctionBegin(), llvm::AsmPrinter::getMBBExceptionSym(), llvm::MachineBasicBlock::getSectionIDNum(), llvm::MachineBasicBlock::isBeginSection(), llvm::MachineBasicBlock::isEHPad(), llvm::MachineBasicBlock::isEndSection(), llvm::LandingPadInfo::LandingPadLabel, llvm::EHStreamer::CallSiteEntry::LPad, llvm::AsmPrinter::MAI, MBB, llvm::AsmPrinter::MBBSectionRanges, llvm::AsmPrinter::MF, MI, P, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorImpl< T >::resize(), llvm::SmallVectorBase< Size_T >::size(), llvm::SjLj, and llvm::MCAsmInfo::usesCFIForEH().

Referenced by emitExceptionTable().

computePadMap()

void EHStreamer::computePadMap ( const SmallVectorImpl< const LandingPadInfo * > &  LandingPads, RangeMapType &  PadMap  )

protected

Definition at line 187 of file EHStreamer.cpp.

References assert(), llvm::LandingPadInfo::BeginLabels, llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::count(), llvm::MCSymbol::isDefined(), N, P, and llvm::SmallVectorBase< Size_T >::size().

Referenced by computeCallSiteTable().

emitExceptionTable()

MCSymbol * 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.

Returns the starting symbol of an exception table.

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.

Returns the starting symbol of an exception table.

Definition at line 380 of file EHStreamer.cpp.

References llvm::EHStreamer::CallSiteEntry::Action, Asm, assert(), llvm::SmallVectorTemplateCommon< T, typename >::back(), llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::EHStreamer::CallSiteEntry::BeginLabel, llvm::EHStreamer::CallSiteRange::CallSiteBeginIdx, llvm::EHStreamer::CallSiteRange::CallSiteEndIdx, computeActionsTable(), computeCallSiteTable(), Context, llvm::MCSymbolRefExpr::create(), llvm::MCBinaryExpr::createSub(), llvm::AsmPrinter::createTempSymbol(), llvm::AsmPrinter::CurrentFnSym, llvm::dwarf::DW_EH_PE_absptr, llvm::dwarf::DW_EH_PE_omit, llvm::dwarf::DW_EH_PE_pcrel, llvm::dwarf::DW_EH_PE_udata4, llvm::AsmPrinter::emitAlignment(), llvm::AsmPrinter::emitCallSiteOffset(), llvm::AsmPrinter::emitCallSiteValue(), llvm::AsmPrinter::emitEncodingByte(), llvm::AsmPrinter::emitLabelDifferenceAsULEB128(), llvm::AsmPrinter::emitSLEB128(), emitTypeInfos(), llvm::AsmPrinter::emitULEB128(), llvm::SmallVectorTemplateCommon< T, typename >::end(), llvm::EHStreamer::CallSiteEntry::EndLabel, llvm::EHStreamer::CallSiteRange::FragmentBeginLabel, llvm::MachineFunction::front(), llvm::TargetLoweringObjectFile::getCallSiteEncoding(), llvm::MCAsmInfo::getCodePointerSize(), llvm::MCAsmInfo::getExceptionHandlingType(), llvm::MachineFunction::getFilterIds(), llvm::MachineFunction::getFunction(), llvm::AsmPrinter::getFunctionNumber(), llvm::MachineFunction::getLandingPads(), llvm::AsmPrinter::getMBBExceptionSym(), llvm::MCSymbol::getName(), llvm::AsmPrinter::getObjFileLowering(), llvm::MCContext::getOrCreateSymbol(), llvm::TargetLoweringObjectFile::getSectionForLSDA(), llvm::AsmPrinter::GetSizeOfEncodedValue(), llvm::getSLEB128Size(), llvm::TargetLoweringObjectFile::getTTypeEncoding(), llvm::MachineFunction::getTypeInfos(), llvm::getULEB128Size(), llvm::MCAsmInfo::hasLEB128Directives(), I, llvm::AsmPrinter::isPositionIndependent(), llvm::LandingPadInfo::LandingPadLabel, llvm::EHStreamer::CallSiteEntry::LPad, llvm::AsmPrinter::MAI, llvm::AsmPrinter::MF, llvm::AsmPrinter::OutContext, llvm::AsmPrinter::OutStreamer, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::report_fatal_error(), llvm::SmallVectorImpl< T >::reserve(), llvm::SmallVectorBase< Size_T >::size(), llvm::SjLj, llvm::sort(), llvm::AsmPrinter::TM, and llvm::Wasm.

Referenced by llvm::DwarfCFIException::endFunction(), llvm::ARMException::endFunction(), llvm::WinException::endFunction(), llvm::AIXException::endFunction(), and llvm::WasmException::endFunction().

emitTypeInfos()

void EHStreamer::emitTypeInfos ( unsigned  TTypeEncoding, MCSymbol *  TTBaseLabel  )

protectedvirtual

Definition at line 809 of file EHStreamer.cpp.

References Asm, llvm::AsmPrinter::emitTTypeReference(), llvm::AsmPrinter::emitULEB128(), llvm::MachineFunction::getFilterIds(), llvm::MachineFunction::getTypeInfos(), I, isFilterEHSelector(), llvm::AsmPrinter::MF, llvm::AsmPrinter::OutStreamer, and llvm::reverse().

Referenced by emitExceptionTable().

endInstruction()

void llvm::EHStreamer::endInstruction ( )

inlineoverridevirtual

Process end of an instruction.

Implements llvm::AsmPrinterHandler.

Definition at line 156 of file EHStreamer.h.

isCatchEHSelector()

static bool llvm::EHStreamer::isCatchEHSelector ( int  Selector )

inlinestaticprotected

Definition at line 147 of file EHStreamer.h.

isCleanupEHSelector()

static bool llvm::EHStreamer::isCleanupEHSelector ( int  Selector )

inlinestaticprotected

Definition at line 146 of file EHStreamer.h.

isFilterEHSelector()

static bool llvm::EHStreamer::isFilterEHSelector ( int  Selector )

inlinestaticprotected

Definition at line 145 of file EHStreamer.h.

Referenced by computeActionsTable(), and emitTypeInfos().

setSymbolSize()

void llvm::EHStreamer::setSymbolSize ( const MCSymbol *  Sym, uint64_t  Size  )

inlineoverridevirtual

For symbols that have a size designated (e.g.

common symbols), this tracks that size.

Implements llvm::AsmPrinterHandler.

Definition at line 154 of file EHStreamer.h.

sharedTypeIDs()

unsigned EHStreamer::sharedTypeIDs ( const LandingPadInfo *  L, const LandingPadInfo *  R  )

staticprotected

How many leading type ids two landing pads have in common.

Definition at line 42 of file EHStreamer.cpp.

Referenced by computeActionsTable().

Member Data Documentation

Asm

AsmPrinter* llvm::EHStreamer::Asm

protected

Target of directive emission.

Definition at line 33 of file EHStreamer.h.

Referenced by llvm::DwarfCFIException::beginBasicBlockSection(), llvm::WinException::beginFunclet(), llvm::DwarfCFIException::beginFunction(), llvm::ARMException::beginFunction(), llvm::WinException::beginFunction(), computeActionsTable(), computeCallSiteTable(), llvm::WasmException::computeCallSiteTable(), emitExceptionTable(), emitTypeInfos(), llvm::DwarfCFIException::endBasicBlockSection(), llvm::WinException::endFunclet(), llvm::ARMException::endFunction(), llvm::WinException::endFunction(), llvm::AIXException::endFunction(), llvm::WasmException::endFunction(), llvm::DwarfCFIException::endModule(), llvm::WasmException::endModule(), llvm::WinException::endModule(), llvm::ARMException::markFunctionEnd(), llvm::WinException::markFunctionEnd(), and llvm::WinException::WinException().

MMI

MachineModuleInfo* llvm::EHStreamer::MMI

protected

Collected machine module information.

Definition at line 36 of file EHStreamer.h.

Referenced by llvm::DwarfCFIException::beginBasicBlockSection(), llvm::WinException::beginFunclet(), and llvm::WinException::endModule().

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The documentation for this class was generated from the following files:

• lib/CodeGen/AsmPrinter/EHStreamer.h
• lib/CodeGen/AsmPrinter/EHStreamer.cpp