PrologEpilogInserter.cpp File Reference

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/CodeGen/WinEHFuncInfo.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Pass.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <functional>
#include <limits>
#include <utility>
#include <vector>

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "prologepilog"

Typedefs
using	MBBVector = SmallVector< MachineBasicBlock *, 4 >
using	StackObjSet = SmallSetVector< int, 8 >
	StackObjSet - A set of stack object indexes. More...
using	SavedDbgValuesMap = SmallDenseMap< MachineBasicBlock *, SmallVector< MachineInstr *, 4 >, 4 >

Functions
	STATISTIC (NumLeafFuncWithSpills, "Number of leaf functions with CSRs")
	STATISTIC (NumFuncSeen, "Number of functions seen in PEI")
	INITIALIZE_PASS_BEGIN (PEI, DEBUG_TYPE, "Prologue/Epilogue Insertion", false, false) INITIALIZE_PASS_END(PEI
	STATISTIC (NumBytesStackSpace, "Number of bytes used for stack in all functions")
static void	stashEntryDbgValues (MachineBasicBlock &MBB, SavedDbgValuesMap &EntryDbgValues)
	Stash DBG_VALUEs that describe parameters and which are placed at the start of the block. More...
static void	assignCalleeSavedSpillSlots (MachineFunction &F, const BitVector &SavedRegs, unsigned &MinCSFrameIndex, unsigned &MaxCSFrameIndex)
static void	updateLiveness (MachineFunction &MF)
	Helper function to update the liveness information for the callee-saved registers. More...
static void	insertCSRSaves (MachineBasicBlock &SaveBlock, ArrayRef< CalleeSavedInfo > CSI)
	Insert restore code for the callee-saved registers used in the function. More...
static void	insertCSRRestores (MachineBasicBlock &RestoreBlock, std::vector< CalleeSavedInfo > &CSI)
	Insert restore code for the callee-saved registers used in the function. More...
static void	AdjustStackOffset (MachineFrameInfo &MFI, int FrameIdx, bool StackGrowsDown, int64_t &Offset, unsigned &MaxAlign, unsigned Skew)
	AdjustStackOffset - Helper function used to adjust the stack frame offset. More...
static void	computeFreeStackSlots (MachineFrameInfo &MFI, bool StackGrowsDown, unsigned MinCSFrameIndex, unsigned MaxCSFrameIndex, int64_t FixedCSEnd, BitVector &StackBytesFree)
	Compute which bytes of fixed and callee-save stack area are unused and keep track of them in StackBytesFree. More...
static bool	scavengeStackSlot (MachineFrameInfo &MFI, int FrameIdx, bool StackGrowsDown, unsigned MaxAlign, BitVector &StackBytesFree)
	Assign frame object to an unused portion of the stack in the fixed stack object range. More...
static void	AssignProtectedObjSet (const StackObjSet &UnassignedObjs, SmallSet< int, 16 > &ProtectedObjs, MachineFrameInfo &MFI, bool StackGrowsDown, int64_t &Offset, unsigned &MaxAlign, unsigned Skew)
	AssignProtectedObjSet - Helper function to assign large stack objects (i.e., those required to be close to the Stack Protector) to stack offsets. More...

Variables
static cl::opt< unsigned >	WarnStackSize ("warn-stack-size", cl::Hidden, cl::init((unsigned) -1), cl::desc("Warn for stack size bigger than the given" " number"))
	DEBUG_TYPE
Prologue Epilogue Insertion &Frame	Finalization
Prologue Epilogue Insertion &Frame	false

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "prologepilog"

Definition at line 74 of file PrologEpilogInserter.cpp.

Referenced by stashEntryDbgValues().

Typedef Documentation

MBBVector

using MBBVector = SmallVector<MachineBasicBlock *, 4>

Definition at line 76 of file PrologEpilogInserter.cpp.

SavedDbgValuesMap

using SavedDbgValuesMap = SmallDenseMap<MachineBasicBlock *, SmallVector<MachineInstr *, 4>, 4>

Definition at line 173 of file PrologEpilogInserter.cpp.

StackObjSet

using StackObjSet = SmallSetVector<int, 8>

StackObjSet - A set of stack object indexes.

Definition at line 170 of file PrologEpilogInserter.cpp.

Function Documentation

AdjustStackOffset()

static void AdjustStackOffset ( MachineFrameInfo &  MFI, int  FrameIdx, bool  StackGrowsDown, int64_t &  Offset, unsigned &  MaxAlign, unsigned  Skew  )

inlinestatic

AdjustStackOffset - Helper function used to adjust the stack frame offset.

Definition at line 634 of file PrologEpilogInserter.cpp.

References llvm::alignTo(), llvm::dbgs(), llvm::MachineFrameInfo::getObjectAlignment(), llvm::MachineFrameInfo::getObjectSize(), LLVM_DEBUG, llvm::max(), and llvm::MachineFrameInfo::setObjectOffset().

Referenced by AssignProtectedObjSet(), and INITIALIZE_PASS().

assignCalleeSavedSpillSlots()

static void assignCalleeSavedSpillSlots ( MachineFunction &  F, const BitVector &  SavedRegs, unsigned &  MinCSFrameIndex, unsigned &  MaxCSFrameIndex  )

static

Definition at line 380 of file PrologEpilogInserter.cpp.

References llvm::TargetFrameLowering::assignCalleeSavedSpillSlots(), llvm::MachineFrameInfo::CreateFixedSpillStackObject(), llvm::MachineFrameInfo::CreateStackObject(), llvm::BitVector::empty(), llvm::MachineRegisterInfo::getCalleeSavedRegs(), llvm::TargetFrameLowering::getCalleeSavedSpillSlots(), llvm::MachineFunction::getFrameInfo(), llvm::TargetSubtargetInfo::getFrameLowering(), llvm::TargetRegisterInfo::getMinimalPhysRegClass(), llvm::MachineFunction::getRegInfo(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::TargetRegisterInfo::getSpillAlignment(), llvm::TargetRegisterInfo::getSpillSize(), llvm::TargetFrameLowering::getStackAlignment(), llvm::MachineFunction::getSubtarget(), llvm::TargetRegisterInfo::hasReservedSpillSlot(), llvm::TargetFrameLowering::SpillSlot::Offset, llvm::TargetFrameLowering::SpillSlot::Reg, Reg, llvm::MachineFrameInfo::setCalleeSavedInfo(), Size, and llvm::BitVector::test().

Referenced by insertCSRRestores().

AssignProtectedObjSet()

static void AssignProtectedObjSet ( const StackObjSet &  UnassignedObjs, SmallSet< int, 16 > &  ProtectedObjs, MachineFrameInfo &  MFI, bool  StackGrowsDown, int64_t &  Offset, unsigned &  MaxAlign, unsigned  Skew  )

static

AssignProtectedObjSet - Helper function to assign large stack objects (i.e., those required to be close to the Stack Protector) to stack offsets.

Definition at line 768 of file PrologEpilogInserter.cpp.

References llvm::TargetFrameLowering::adjustForHiPEPrologue(), llvm::TargetFrameLowering::adjustForSegmentedStacks(), llvm::MachineFrameInfo::adjustsStack(), AdjustStackOffset(), llvm::alignTo(), llvm::DIExpression::ApplyOffset, assert(), llvm::SetVector< T, Vector, Set >::begin(), llvm::SmallVectorTemplateCommon< T >::begin(), llvm::MachineBasicBlock::begin(), llvm::MachineOperand::ChangeToRegister(), computeFreeStackSlots(), llvm::SmallPtrSetImpl< NodeRef >::count(), llvm::dbgs(), llvm::TargetStackID::Default, llvm::df_ext_begin(), llvm::df_ext_end(), llvm::numbers::e, E, llvm::TargetFrameLowering::eliminateCallFramePseudoInstr(), llvm::TargetRegisterInfo::eliminateFrameIndex(), llvm::TargetFrameLowering::emitEpilogue(), llvm::TargetFrameLowering::emitPrologue(), llvm::SmallVectorBase::empty(), llvm::SetVector< T, Vector, Set >::empty(), llvm::TargetFrameLowering::enableStackSlotScavenging(), llvm::SetVector< T, Vector, Set >::end(), llvm::SmallVectorTemplateCommon< T >::end(), llvm::MachineBasicBlock::end(), llvm::Function::getCallingConv(), llvm::MachineInstr::getDebugExpression(), llvm::TargetFrameLowering::getFrameIndexReference(), llvm::TargetFrameLowering::getFrameIndexReferencePreferSP(), llvm::MachineFunction::getFrameInfo(), llvm::TargetSubtargetInfo::getFrameLowering(), llvm::MachineFunction::getFunction(), llvm::MachineOperand::getImm(), llvm::MachineOperand::getIndex(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::MachineFrameInfo::getLocalFrameMaxAlign(), llvm::MachineFrameInfo::getLocalFrameObjectCount(), llvm::MachineFrameInfo::getLocalFrameObjectMap(), llvm::MachineFrameInfo::getLocalFrameSize(), llvm::MachineFrameInfo::getMaxAlignment(), llvm::MachineFrameInfo::getMaxCallFrameSize(), llvm::MachineFunction::getMMI(), llvm::MachineBasicBlock::getNumber(), llvm::MachineFunction::getNumBlockIDs(), llvm::MachineInstr::getNumOperands(), llvm::MachineFrameInfo::getObjectAlignment(), llvm::MachineFrameInfo::getObjectIndexBegin(), llvm::MachineFrameInfo::getObjectIndexEnd(), llvm::MachineFrameInfo::getObjectOffset(), llvm::MachineFrameInfo::getObjectSize(), llvm::MachineFrameInfo::getObjectSSPLayout(), llvm::TargetFrameLowering::getOffsetOfLocalArea(), llvm::MachineInstr::getOpcode(), llvm::MachineInstr::getOperand(), llvm::TargetMachine::getOptLevel(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::TargetFrameLowering::getStackAlignment(), llvm::TargetFrameLowering::getStackAlignmentSkew(), llvm::TargetFrameLowering::getStackGrowthDirection(), llvm::MachineFrameInfo::getStackID(), llvm::MachineFrameInfo::getStackProtectorIndex(), llvm::MachineFunction::getSubtarget(), llvm::MachineFunction::getTarget(), llvm::TargetFrameLowering::getTransientStackAlignment(), llvm::MachineFrameInfo::getUseLocalStackAllocationBlock(), llvm::MachineFunction::getWinEHFuncInfo(), llvm::TargetFrameLowering::hasFP(), llvm::TargetFrameLowering::hasReservedCallFrame(), llvm::MachineFrameInfo::hasStackProtectorIndex(), llvm::MachineFrameInfo::hasVarSizedObjects(), llvm::CallingConv::HiPE, I, llvm::ARM_PROC::IE, if(), llvm::TargetFrameLowering::inlineStackProbe(), llvm::SetVector< T, Vector, Set >::insert(), llvm::SmallSet< T, N, C >::insert(), llvm::DIExpression::isComplex(), llvm::MachineFrameInfo::isDeadObjectIndex(), llvm::MachineInstr::isDebugValue(), llvm::MachineOperand::isFI(), llvm::TargetFrameLowering::isFPCloseToIncomingSP(), llvm::DIExpression::isImplicit(), llvm::MachineInstr::isIndirectDebugValue(), llvm::MachineFrameInfo::isObjectPreAllocated(), LLVM_DEBUG, llvm_unreachable, llvm::max(), MI, llvm::TargetFrameLowering::needsFrameIndexResolution(), llvm::TargetRegisterInfo::needsStackRealignment(), llvm::CodeGenOpt::None, llvm::TargetMachine::Options, llvm::TargetFrameLowering::orderFrameObjects(), llvm::DIExpression::prepend(), llvm::DIExpression::prependOpcodes(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), Reg, llvm::TargetRegisterInfo::requiresFrameIndexReplacementScavenging(), llvm::SmallVectorImpl< T >::resize(), scavengeStackSlot(), llvm::MachineModuleInfo::setHasNosplitStack(), llvm::MachineModuleInfo::setHasSplitStack(), llvm::MachineOperand::setImm(), llvm::MachineOperand::setIsDebug(), llvm::MachineOperand::setMetadata(), llvm::MachineFrameInfo::setObjectOffset(), llvm::MachineFrameInfo::setStackSize(), llvm::MachineFunction::shouldSplitStack(), Size, llvm::MachineFrameInfo::SSPLK_AddrOf, llvm::MachineFrameInfo::SSPLK_LargeArray, llvm::MachineFrameInfo::SSPLK_None, llvm::MachineFrameInfo::SSPLK_SmallArray, llvm::ARM_MB::ST, llvm::TargetFrameLowering::StackGrowsDown, llvm::TargetOptions::StackSymbolOrdering, llvm::DIExpression::StackValue, llvm::TargetFrameLowering::targetHandlesStackFrameRounding(), TII, TRI, llvm::TargetRegisterInfo::useFPForScavengingIndex(), and llvm::Align::value().

Referenced by INITIALIZE_PASS().

computeFreeStackSlots()

static void computeFreeStackSlots ( MachineFrameInfo &  MFI, bool  StackGrowsDown, unsigned  MinCSFrameIndex, unsigned  MaxCSFrameIndex, int64_t  FixedCSEnd, BitVector &  StackBytesFree  )

inlinestatic

Compute which bytes of fixed and callee-save stack area are unused and keep track of them in StackBytesFree.

Definition at line 665 of file PrologEpilogInserter.cpp.

References llvm::TargetStackID::Default, llvm::MachineFrameInfo::getObjectIndexBegin(), llvm::MachineFrameInfo::getObjectOffset(), llvm::MachineFrameInfo::getObjectSize(), llvm::MachineFrameInfo::getStackID(), llvm::max(), llvm::SmallVectorTemplateBase< T >::push_back(), llvm::BitVector::reset(), and llvm::BitVector::resize().

Referenced by AssignProtectedObjSet().

INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	PEI	,
		DEBUG_TYPE	,
		"Prologue/Epilogue Insertion"	,
		false	,
		false
	)

insertCSRRestores()

static void insertCSRRestores ( MachineBasicBlock &  RestoreBlock, std::vector< CalleeSavedInfo > &  CSI  )

static

Insert restore code for the callee-saved registers used in the function.

Definition at line 560 of file PrologEpilogInserter.cpp.

References assert(), assignCalleeSavedSpillSlots(), llvm::MachineBasicBlock::begin(), llvm::BuildMI(), llvm::TargetFrameLowering::determineCalleeSaves(), F(), llvm::MCInstrInfo::get(), llvm::MachineFrameInfo::getCalleeSavedInfo(), llvm::MachineBasicBlock::getFirstTerminator(), llvm::MachineFunction::getFrameInfo(), llvm::TargetSubtargetInfo::getFrameLowering(), llvm::MachineFunction::getFunction(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::getKillRegState(), llvm::TargetRegisterInfo::getMinimalPhysRegClass(), llvm::MachineBasicBlock::getParent(), llvm::MachineFunction::getProperties(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::MachineFunction::getSubtarget(), llvm::MachineFrameInfo::hasCalls(), llvm::MachineFunctionProperties::hasProperty(), I, insertCSRSaves(), llvm::TargetInstrInfo::loadRegFromStackSlot(), llvm::max(), llvm::MachineFunctionProperties::NoVRegs, Reg, llvm::TargetFrameLowering::restoreCalleeSavedRegisters(), llvm::reverse(), llvm::MachineFrameInfo::setCalleeSavedInfoValid(), TII, TRI, and updateLiveness().

insertCSRSaves()

static void insertCSRSaves ( MachineBasicBlock &  SaveBlock, ArrayRef< CalleeSavedInfo >  CSI  )

static

Insert restore code for the callee-saved registers used in the function.

Definition at line 533 of file PrologEpilogInserter.cpp.

References llvm::MachineBasicBlock::begin(), llvm::BuildMI(), llvm::MCInstrInfo::get(), llvm::TargetSubtargetInfo::getFrameLowering(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::getKillRegState(), llvm::TargetRegisterInfo::getMinimalPhysRegClass(), llvm::MachineBasicBlock::getParent(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::MachineFunction::getSubtarget(), I, Reg, llvm::TargetFrameLowering::spillCalleeSavedRegisters(), llvm::TargetInstrInfo::storeRegToStackSlot(), TII, and TRI.

Referenced by insertCSRRestores().

scavengeStackSlot()

static bool scavengeStackSlot ( MachineFrameInfo &  MFI, int  FrameIdx, bool  StackGrowsDown, unsigned  MaxAlign, BitVector &  StackBytesFree  )

inlinestatic

Assign frame object to an unused portion of the stack in the fixed stack object range.

Return true if the allocation was successful.

Definition at line 707 of file PrologEpilogInserter.cpp.

References llvm::alignTo(), llvm::BitVector::clear(), llvm::dbgs(), llvm::BitVector::find_first(), llvm::BitVector::find_next(), llvm::MachineFrameInfo::getObjectAlignment(), llvm::MachineFrameInfo::getObjectSize(), llvm::MachineFrameInfo::isVariableSizedObjectIndex(), LLVM_DEBUG, llvm::BitVector::none(), llvm::BitVector::reset(), llvm::MachineFrameInfo::setObjectOffset(), llvm::BitVector::size(), and llvm::BitVector::test().

Referenced by AssignProtectedObjSet().

stashEntryDbgValues()

static void stashEntryDbgValues ( MachineBasicBlock &  MBB, SavedDbgValuesMap &  EntryDbgValues  )

static

Stash DBG_VALUEs that describe parameters and which are placed at the start of the block.

Later on, after the prologue code has been emitted, the stashed DBG_VALUEs will be reinserted at the start of the block.

Definition at line 178 of file PrologEpilogInserter.cpp.

References llvm::MachineFrameInfo::adjustsStack(), assert(), llvm::MachineFunction::begin(), llvm::TargetFrameLowering::canSimplifyCallFramePseudos(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::count(), DEBUG_TYPE, llvm::LLVMContext::diagnose(), llvm::numbers::e, E, llvm::TargetFrameLowering::eliminateCallFramePseudoInstr(), llvm::MachineFunction::end(), llvm::InlineAsm::Extra_IsAlignStack, F(), llvm::DIExpression::fragmentsOverlap(), llvm::MachineFunction::front(), llvm::TargetInstrInfo::getCallFrameDestroyOpcode(), llvm::TargetInstrInfo::getCallFrameSetupOpcode(), llvm::Function::getContext(), llvm::MachineFunction::getFrameInfo(), llvm::TargetSubtargetInfo::getFrameLowering(), llvm::TargetInstrInfo::getFrameSize(), llvm::MachineFunction::getFunction(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::MachineFrameInfo::getMaxCallFrameSize(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::MachineFrameInfo::getRestorePoint(), llvm::MachineFrameInfo::getSavePoint(), llvm::MachineFrameInfo::getStackSize(), llvm::Function::getSubprogram(), llvm::MachineFunction::getSubtarget(), llvm::MachineFunction::getTarget(), llvm::Function::hasFnAttribute(), I, llvm::TargetInstrInfo::isFrameInstr(), llvm::MachineFrameInfo::isMaxCallFrameSizeComputed(), MI, llvm::InlineAsm::MIOp_ExtraInfo, llvm::none_of(), llvm::TargetFrameLowering::processFunctionBeforeFrameFinalized(), llvm::SmallVectorTemplateBase< T >::push_back(), llvm::MachineBasicBlock::push_back(), llvm::TargetRegisterInfo::requiresFrameIndexScavenging(), llvm::TargetRegisterInfo::requiresRegisterScavenging(), llvm::scavengeFrameVirtualRegs(), llvm::MachineFrameInfo::setAdjustsStack(), llvm::MachineFrameInfo::setMaxCallFrameSize(), llvm::MachineFrameInfo::setRestorePoint(), llvm::MachineFrameInfo::setSavePoint(), Size, TII, TRI, llvm::LLVMTargetMachine::usesPhysRegsForPEI(), and WarnStackSize.

STATISTIC() [1/3]

STATISTIC	(	NumLeafFuncWithSpills	,
		"Number of leaf functions with CSRs"
	)

STATISTIC() [2/3]

STATISTIC	(	NumFuncSeen	,
		"Number of functions seen in PEI"
	)

STATISTIC() [3/3]

STATISTIC	(	NumBytesStackSpace	,
		"Number of bytes used for stack in all functions"
	)

updateLiveness()

static void updateLiveness ( MachineFunction &  MF )

static

Helper function to update the liveness information for the callee-saved registers.

Definition at line 460 of file PrologEpilogInserter.cpp.

References llvm::MachineFunction::front(), llvm::MachineFunction::getFrameInfo(), and llvm::MachineFrameInfo::getSavePoint().

Referenced by insertCSRRestores().

Variable Documentation

DEBUG_TYPE

DEBUG_TYPE

Definition at line 150 of file PrologEpilogInserter.cpp.

false

Prologue Epilogue Insertion& Frame false

Definition at line 150 of file PrologEpilogInserter.cpp.

Finalization

Prologue Epilogue Insertion& Frame Finalization

Definition at line 150 of file PrologEpilogInserter.cpp.

WarnStackSize

cl::opt<unsigned> WarnStackSize("warn-stack-size", cl::Hidden, cl::init((unsigned) -1), cl::desc("Warn for stack size bigger than the given" " number"))

static

Referenced by stashEntryDbgValues().