LLVM 19.0.0git
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llvm::AVRFrameLowering Class Reference

Utilities for creating function call frames. More...

#include "Target/AVR/AVRFrameLowering.h"

Inheritance diagram for llvm::AVRFrameLowering:
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Public Member Functions

 AVRFrameLowering ()
 
void emitPrologue (MachineFunction &MF, MachineBasicBlock &MBB) const override
 emitProlog/emitEpilog - These methods insert prolog and epilog code into the function.
 
void emitEpilogue (MachineFunction &MF, MachineBasicBlock &MBB) const override
 
bool hasFP (const MachineFunction &MF) const override
 hasFP - Return true if the specified function should have a dedicated frame pointer register.
 
bool spillCalleeSavedRegisters (MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, ArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const override
 spillCalleeSavedRegisters - Issues instruction(s) to spill all callee saved registers and returns true if it isn't possible / profitable to do so by issuing a series of store instructions via storeRegToStackSlot().
 
bool restoreCalleeSavedRegisters (MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, MutableArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const override
 restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee saved registers and returns true if it isn't possible / profitable to do so by issuing a series of load instructions via loadRegToStackSlot().
 
bool hasReservedCallFrame (const MachineFunction &MF) const override
 hasReservedCallFrame - Under normal circumstances, when a frame pointer is not required, we reserve argument space for call sites in the function immediately on entry to the current function.
 
bool canSimplifyCallFramePseudos (const MachineFunction &MF) const override
 canSimplifyCallFramePseudos - When possible, it's best to simplify the call frame pseudo ops before doing frame index elimination.
 
void determineCalleeSaves (MachineFunction &MF, BitVector &SavedRegs, RegScavenger *RS=nullptr) const override
 This method determines which of the registers reported by TargetRegisterInfo::getCalleeSavedRegs() should actually get saved.
 
MachineBasicBlock::iterator eliminateCallFramePseudoInstr (MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const override
 This method is called during prolog/epilog code insertion to eliminate call frame setup and destroy pseudo instructions (but only if the Target is using them).
 
- Public Member Functions inherited from llvm::TargetFrameLowering
 TargetFrameLowering (StackDirection D, Align StackAl, int LAO, Align TransAl=Align(1), bool StackReal=true)
 
virtual ~TargetFrameLowering ()
 
StackDirection getStackGrowthDirection () const
 getStackGrowthDirection - Return the direction the stack grows
 
unsigned getStackAlignment () const
 getStackAlignment - This method returns the number of bytes to which the stack pointer must be aligned on entry to a function.
 
Align getStackAlign () const
 getStackAlignment - This method returns the number of bytes to which the stack pointer must be aligned on entry to a function.
 
virtual uint64_t getStackThreshold () const
 getStackThreshold - Return the maximum stack size
 
int alignSPAdjust (int SPAdj) const
 alignSPAdjust - This method aligns the stack adjustment to the correct alignment.
 
Align getTransientStackAlign () const
 getTransientStackAlignment - This method returns the number of bytes to which the stack pointer must be aligned at all times, even between calls.
 
bool isStackRealignable () const
 isStackRealignable - This method returns whether the stack can be realigned.
 
virtual bool isStackIdSafeForLocalArea (unsigned StackId) const
 This method returns whether or not it is safe for an object with the given stack id to be bundled into the local area.
 
int getOffsetOfLocalArea () const
 getOffsetOfLocalArea - This method returns the offset of the local area from the stack pointer on entrance to a function.
 
virtual bool allocateScavengingFrameIndexesNearIncomingSP (const MachineFunction &MF) const
 Control the placement of special register scavenging spill slots when allocating a stack frame.
 
virtual bool assignCalleeSavedSpillSlots (MachineFunction &MF, const TargetRegisterInfo *TRI, std::vector< CalleeSavedInfo > &CSI, unsigned &MinCSFrameIndex, unsigned &MaxCSFrameIndex) const
 assignCalleeSavedSpillSlots - Allows target to override spill slot assignment logic.
 
virtual bool assignCalleeSavedSpillSlots (MachineFunction &MF, const TargetRegisterInfo *TRI, std::vector< CalleeSavedInfo > &CSI) const
 
virtual const SpillSlotgetCalleeSavedSpillSlots (unsigned &NumEntries) const
 getCalleeSavedSpillSlots - This method returns a pointer to an array of pairs, that contains an entry for each callee saved register that must be spilled to a particular stack location if it is spilled.
 
virtual bool targetHandlesStackFrameRounding () const
 targetHandlesStackFrameRounding - Returns true if the target is responsible for rounding up the stack frame (probably at emitPrologue time).
 
virtual bool enableShrinkWrapping (const MachineFunction &MF) const
 Returns true if the target will correctly handle shrink wrapping.
 
virtual bool enableStackSlotScavenging (const MachineFunction &MF) const
 Returns true if the stack slot holes in the fixed and callee-save stack area should be used when allocating other stack locations to reduce stack size.
 
virtual bool enableCalleeSaveSkip (const MachineFunction &MF) const
 Returns true if the target can safely skip saving callee-saved registers for noreturn nounwind functions.
 
virtual void emitPrologue (MachineFunction &MF, MachineBasicBlock &MBB) const =0
 emitProlog/emitEpilog - These methods insert prolog and epilog code into the function.
 
virtual void emitEpilogue (MachineFunction &MF, MachineBasicBlock &MBB) const =0
 
virtual void emitZeroCallUsedRegs (BitVector RegsToZero, MachineBasicBlock &MBB) const
 emitZeroCallUsedRegs - Zeros out call used registers.
 
virtual void emitCalleeSavedFrameMovesFullCFA (MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI) const
 With basic block sections, emit callee saved frame moves for basic blocks that are in a different section.
 
virtual bool enableCFIFixup (MachineFunction &MF) const
 Returns true if we may need to fix the unwind information for the function.
 
virtual void resetCFIToInitialState (MachineBasicBlock &MBB) const
 Emit CFI instructions that recreate the state of the unwind information upon fucntion entry.
 
virtual void inlineStackProbe (MachineFunction &MF, MachineBasicBlock &PrologueMBB) const
 Replace a StackProbe stub (if any) with the actual probe code inline.
 
virtual bool stackProbeFunctionModifiesSP () const
 Does the stack probe function call return with a modified stack pointer?
 
virtual void adjustForSegmentedStacks (MachineFunction &MF, MachineBasicBlock &PrologueMBB) const
 Adjust the prologue to have the function use segmented stacks.
 
virtual void adjustForHiPEPrologue (MachineFunction &MF, MachineBasicBlock &PrologueMBB) const
 Adjust the prologue to add Erlang Run-Time System (ERTS) specific code in the assembly prologue to explicitly handle the stack.
 
virtual bool spillCalleeSavedRegisters (MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, ArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const
 spillCalleeSavedRegisters - Issues instruction(s) to spill all callee saved registers and returns true if it isn't possible / profitable to do so by issuing a series of store instructions via storeRegToStackSlot().
 
virtual bool restoreCalleeSavedRegisters (MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, MutableArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const
 restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee saved registers and returns true if it isn't possible / profitable to do so by issuing a series of load instructions via loadRegToStackSlot().
 
virtual bool keepFramePointer (const MachineFunction &MF) const
 Return true if the target wants to keep the frame pointer regardless of the function attribute "frame-pointer".
 
virtual bool hasFP (const MachineFunction &MF) const =0
 hasFP - Return true if the specified function should have a dedicated frame pointer register.
 
virtual bool hasReservedCallFrame (const MachineFunction &MF) const
 hasReservedCallFrame - Under normal circumstances, when a frame pointer is not required, we reserve argument space for call sites in the function immediately on entry to the current function.
 
virtual bool canSimplifyCallFramePseudos (const MachineFunction &MF) const
 canSimplifyCallFramePseudos - When possible, it's best to simplify the call frame pseudo ops before doing frame index elimination.
 
virtual bool needsFrameIndexResolution (const MachineFunction &MF) const
 
virtual StackOffset getFrameIndexReference (const MachineFunction &MF, int FI, Register &FrameReg) const
 getFrameIndexReference - This method should return the base register and offset used to reference a frame index location.
 
virtual StackOffset getFrameIndexReferencePreferSP (const MachineFunction &MF, int FI, Register &FrameReg, bool IgnoreSPUpdates) const
 Same as getFrameIndexReference, except that the stack pointer (as opposed to the frame pointer) will be the preferred value for FrameReg.
 
virtual StackOffset getNonLocalFrameIndexReference (const MachineFunction &MF, int FI) const
 getNonLocalFrameIndexReference - This method returns the offset used to reference a frame index location.
 
virtual void getCalleeSaves (const MachineFunction &MF, BitVector &SavedRegs) const
 Returns the callee-saved registers as computed by determineCalleeSaves in the BitVector SavedRegs.
 
virtual void determineCalleeSaves (MachineFunction &MF, BitVector &SavedRegs, RegScavenger *RS=nullptr) const
 This method determines which of the registers reported by TargetRegisterInfo::getCalleeSavedRegs() should actually get saved.
 
virtual void processFunctionBeforeFrameFinalized (MachineFunction &MF, RegScavenger *RS=nullptr) const
 processFunctionBeforeFrameFinalized - This method is called immediately before the specified function's frame layout (MF.getFrameInfo()) is finalized.
 
virtual void processFunctionBeforeFrameIndicesReplaced (MachineFunction &MF, RegScavenger *RS=nullptr) const
 processFunctionBeforeFrameIndicesReplaced - This method is called immediately before MO_FrameIndex operands are eliminated, but after the frame is finalized.
 
virtual unsigned getWinEHParentFrameOffset (const MachineFunction &MF) const
 
virtual MachineBasicBlock::iterator eliminateCallFramePseudoInstr (MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const
 This method is called during prolog/epilog code insertion to eliminate call frame setup and destroy pseudo instructions (but only if the Target is using them).
 
virtual void orderFrameObjects (const MachineFunction &MF, SmallVectorImpl< int > &objectsToAllocate) const
 Order the symbols in the local stack frame.
 
virtual bool canUseAsPrologue (const MachineBasicBlock &MBB) const
 Check whether or not the given MBB can be used as a prologue for the target.
 
virtual bool canUseAsEpilogue (const MachineBasicBlock &MBB) const
 Check whether or not the given MBB can be used as a epilogue for the target.
 
virtual TargetStackID::Value getStackIDForScalableVectors () const
 Returns the StackID that scalable vectors should be associated with.
 
virtual bool isSupportedStackID (TargetStackID::Value ID) const
 
virtual bool isProfitableForNoCSROpt (const Function &F) const
 Check if the no-CSR optimisation is profitable for the given function.
 
virtual int getInitialCFAOffset (const MachineFunction &MF) const
 Return initial CFA offset value i.e.
 
virtual Register getInitialCFARegister (const MachineFunction &MF) const
 Return initial CFA register value i.e.
 
virtual DwarfFrameBase getDwarfFrameBase (const MachineFunction &MF) const
 Return the frame base information to be encoded in the DWARF subprogram debug info.
 

Additional Inherited Members

- Public Types inherited from llvm::TargetFrameLowering
enum  StackDirection { StackGrowsUp , StackGrowsDown }
 
- Static Public Member Functions inherited from llvm::TargetFrameLowering
static bool isSafeForNoCSROpt (const Function &F)
 Check if given function is safe for not having callee saved registers.
 

Detailed Description

Utilities for creating function call frames.

Definition at line 17 of file AVRFrameLowering.h.

Constructor & Destructor Documentation

◆ AVRFrameLowering()

llvm::AVRFrameLowering::AVRFrameLowering ( )
explicit

Definition at line 30 of file AVRFrameLowering.cpp.

Member Function Documentation

◆ canSimplifyCallFramePseudos()

bool llvm::AVRFrameLowering::canSimplifyCallFramePseudos ( const MachineFunction MF) const
overridevirtual

canSimplifyCallFramePseudos - When possible, it's best to simplify the call frame pseudo ops before doing frame index elimination.

This is possible only when frame index references between the pseudos won't need adjusting for the call frame adjustments. Normally, that's true if the function has a reserved call frame or a frame pointer. Some targets (Thumb2, for example) may have more complicated criteria, however, and can override this behavior.

Reimplemented from llvm::TargetFrameLowering.

Definition at line 33 of file AVRFrameLowering.cpp.

◆ determineCalleeSaves()

void llvm::AVRFrameLowering::determineCalleeSaves ( MachineFunction MF,
BitVector SavedRegs,
RegScavenger RS = nullptr 
) const
overridevirtual

This method determines which of the registers reported by TargetRegisterInfo::getCalleeSavedRegs() should actually get saved.

The default implementation checks populates the SavedRegs bitset with all registers which are modified in the function, targets may override this function to save additional registers. This method also sets up the register scavenger ensuring there is a free register or a frameindex available. This method should not be called by any passes outside of PEI, because it may change state passed in by MF and RS. The preferred interface outside PEI is getCalleeSaves.

Reimplemented from llvm::TargetFrameLowering.

Definition at line 418 of file AVRFrameLowering.cpp.

References llvm::TargetFrameLowering::determineCalleeSaves(), hasFP(), and llvm::BitVector::set().

◆ eliminateCallFramePseudoInstr()

MachineBasicBlock::iterator llvm::AVRFrameLowering::eliminateCallFramePseudoInstr ( MachineFunction MF,
MachineBasicBlock MBB,
MachineBasicBlock::iterator  MI 
) const
overridevirtual

This method is called during prolog/epilog code insertion to eliminate call frame setup and destroy pseudo instructions (but only if the Target is using them).

It is responsible for eliminating these instructions, replacing them with concrete instructions. This method need only be implemented if using call frame setup/destroy pseudo instructions. Returns an iterator pointing to the instruction after the replaced one.

Reimplemented from llvm::TargetFrameLowering.

Definition at line 347 of file AVRFrameLowering.cpp.

References llvm::MachineInstrBuilder::addImm(), llvm::MachineInstrBuilder::addReg(), assert(), llvm::BuildMI(), DL, llvm::fixStackStores(), llvm::AVRSubtarget::getInstrInfo(), llvm::TargetFrameLowering::getStackAlign(), llvm::MachineFunction::getSubtarget(), hasReservedCallFrame(), llvm::RegState::Kill, MBB, MI, and TII.

◆ emitEpilogue()

void llvm::AVRFrameLowering::emitEpilogue ( MachineFunction MF,
MachineBasicBlock MBB 
) const
overridevirtual

◆ emitPrologue()

void llvm::AVRFrameLowering::emitPrologue ( MachineFunction MF,
MachineBasicBlock MBB 
) const
overridevirtual

◆ hasFP()

bool llvm::AVRFrameLowering::hasFP ( const MachineFunction MF) const
overridevirtual

hasFP - Return true if the specified function should have a dedicated frame pointer register.

For most targets this is true only if the function has variable sized allocas or if frame pointer elimination is disabled.

Implements llvm::TargetFrameLowering.

Definition at line 235 of file AVRFrameLowering.cpp.

References llvm::MachineFunction::getFrameInfo(), llvm::AVRMachineFunctionInfo::getHasAllocas(), llvm::AVRMachineFunctionInfo::getHasSpills(), llvm::AVRMachineFunctionInfo::getHasStackArgs(), llvm::MachineFunction::getInfo(), and llvm::MachineFrameInfo::hasVarSizedObjects().

Referenced by determineCalleeSaves(), emitEpilogue(), emitPrologue(), and hasReservedCallFrame().

◆ hasReservedCallFrame()

bool llvm::AVRFrameLowering::hasReservedCallFrame ( const MachineFunction MF) const
overridevirtual

hasReservedCallFrame - Under normal circumstances, when a frame pointer is not required, we reserve argument space for call sites in the function immediately on entry to the current function.

This eliminates the need for add/sub sp brackets around call sites. Returns true if the call frame is included as part of the stack frame.

Reimplemented from llvm::TargetFrameLowering.

Definition at line 40 of file AVRFrameLowering.cpp.

References llvm::MachineFunction::getFrameInfo(), hasFP(), and llvm::MachineFrameInfo::hasVarSizedObjects().

Referenced by eliminateCallFramePseudoInstr().

◆ restoreCalleeSavedRegisters()

bool llvm::AVRFrameLowering::restoreCalleeSavedRegisters ( MachineBasicBlock MBB,
MachineBasicBlock::iterator  MI,
MutableArrayRef< CalleeSavedInfo CSI,
const TargetRegisterInfo TRI 
) const
overridevirtual

restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee saved registers and returns true if it isn't possible / profitable to do so by issuing a series of load instructions via loadRegToStackSlot().

If it returns true, and any of the registers in CSI is not restored, it sets the corresponding Restored flag in CSI to false. Returns false otherwise.

Reimplemented from llvm::TargetFrameLowering.

Definition at line 293 of file AVRFrameLowering.cpp.

References assert(), llvm::BuildMI(), DL, llvm::ArrayRef< T >::empty(), llvm::AVRSubtarget::getInstrInfo(), llvm::MachineFunction::getSubtarget(), MBB, MI, Reg, TII, and TRI.

◆ spillCalleeSavedRegisters()

bool llvm::AVRFrameLowering::spillCalleeSavedRegisters ( MachineBasicBlock MBB,
MachineBasicBlock::iterator  MI,
ArrayRef< CalleeSavedInfo CSI,
const TargetRegisterInfo TRI 
) const
overridevirtual

spillCalleeSavedRegisters - Issues instruction(s) to spill all callee saved registers and returns true if it isn't possible / profitable to do so by issuing a series of store instructions via storeRegToStackSlot().

Returns false otherwise.

Reimplemented from llvm::TargetFrameLowering.

Definition at line 243 of file AVRFrameLowering.cpp.

References llvm::MachineInstrBuilder::addReg(), assert(), llvm::BuildMI(), DL, llvm::ArrayRef< T >::empty(), llvm::MachineInstr::FrameSetup, llvm::MachineFunction::getInfo(), llvm::AVRSubtarget::getInstrInfo(), llvm::getKillRegState(), llvm::AVRSubtarget::getRegisterInfo(), llvm::MachineFunction::getSubtarget(), I, MBB, MI, Reg, llvm::reverse(), llvm::AVRMachineFunctionInfo::setCalleeSavedFrameSize(), llvm::MachineInstrBuilder::setMIFlag(), TII, and TRI.


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