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Diffstat (limited to 'include/llvm/Target/TargetFrameLowering.h')
| -rw-r--r-- | include/llvm/Target/TargetFrameLowering.h | 348 |
1 files changed, 0 insertions, 348 deletions
diff --git a/include/llvm/Target/TargetFrameLowering.h b/include/llvm/Target/TargetFrameLowering.h deleted file mode 100644 index 31017cbc27b8..000000000000 --- a/include/llvm/Target/TargetFrameLowering.h +++ /dev/null @@ -1,348 +0,0 @@ -//===-- llvm/Target/TargetFrameLowering.h ---------------------------*- C++ -*-===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// Interface to describe the layout of a stack frame on the target machine. -// -//===----------------------------------------------------------------------===// - -#ifndef LLVM_TARGET_TARGETFRAMELOWERING_H -#define LLVM_TARGET_TARGETFRAMELOWERING_H - -#include "llvm/CodeGen/MachineBasicBlock.h" -#include <utility> -#include <vector> - -namespace llvm { - class BitVector; - class CalleeSavedInfo; - class MachineFunction; - class RegScavenger; - -/// Information about stack frame layout on the target. It holds the direction -/// of stack growth, the known stack alignment on entry to each function, and -/// the offset to the locals area. -/// -/// The offset to the local area is the offset from the stack pointer on -/// function entry to the first location where function data (local variables, -/// spill locations) can be stored. -class TargetFrameLowering { -public: - enum StackDirection { - StackGrowsUp, // Adding to the stack increases the stack address - StackGrowsDown // Adding to the stack decreases the stack address - }; - - // Maps a callee saved register to a stack slot with a fixed offset. - struct SpillSlot { - unsigned Reg; - int Offset; // Offset relative to stack pointer on function entry. - }; -private: - StackDirection StackDir; - unsigned StackAlignment; - unsigned TransientStackAlignment; - int LocalAreaOffset; - bool StackRealignable; -public: - TargetFrameLowering(StackDirection D, unsigned StackAl, int LAO, - unsigned TransAl = 1, bool StackReal = true) - : StackDir(D), StackAlignment(StackAl), TransientStackAlignment(TransAl), - LocalAreaOffset(LAO), StackRealignable(StackReal) {} - - virtual ~TargetFrameLowering(); - - // These methods return information that describes the abstract stack layout - // of the target machine. - - /// getStackGrowthDirection - Return the direction the stack grows - /// - StackDirection getStackGrowthDirection() const { return StackDir; } - - /// getStackAlignment - This method returns the number of bytes to which the - /// stack pointer must be aligned on entry to a function. Typically, this - /// is the largest alignment for any data object in the target. - /// - unsigned getStackAlignment() const { return StackAlignment; } - - /// alignSPAdjust - This method aligns the stack adjustment to the correct - /// alignment. - /// - int alignSPAdjust(int SPAdj) const { - if (SPAdj < 0) { - SPAdj = -alignTo(-SPAdj, StackAlignment); - } else { - SPAdj = alignTo(SPAdj, StackAlignment); - } - return SPAdj; - } - - /// getTransientStackAlignment - This method returns the number of bytes to - /// which the stack pointer must be aligned at all times, even between - /// calls. - /// - unsigned getTransientStackAlignment() const { - return TransientStackAlignment; - } - - /// isStackRealignable - This method returns whether the stack can be - /// realigned. - bool isStackRealignable() const { - return StackRealignable; - } - - /// Return the skew that has to be applied to stack alignment under - /// certain conditions (e.g. stack was adjusted before function \p MF - /// was called). - virtual unsigned getStackAlignmentSkew(const MachineFunction &MF) const; - - /// getOffsetOfLocalArea - This method returns the offset of the local area - /// from the stack pointer on entrance to a function. - /// - int getOffsetOfLocalArea() const { return LocalAreaOffset; } - - /// isFPCloseToIncomingSP - Return true if the frame pointer is close to - /// the incoming stack pointer, false if it is close to the post-prologue - /// stack pointer. - virtual bool isFPCloseToIncomingSP() const { return true; } - - /// assignCalleeSavedSpillSlots - Allows target to override spill slot - /// assignment logic. If implemented, assignCalleeSavedSpillSlots() should - /// assign frame slots to all CSI entries and return true. If this method - /// returns false, spill slots will be assigned using generic implementation. - /// assignCalleeSavedSpillSlots() may add, delete or rearrange elements of - /// CSI. - virtual bool - assignCalleeSavedSpillSlots(MachineFunction &MF, - const TargetRegisterInfo *TRI, - std::vector<CalleeSavedInfo> &CSI) const { - return false; - } - - /// 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. - /// - /// Each entry in this array contains a <register,offset> pair, indicating the - /// fixed offset from the incoming stack pointer that each register should be - /// spilled at. If a register is not listed here, the code generator is - /// allowed to spill it anywhere it chooses. - /// - virtual const SpillSlot * - getCalleeSavedSpillSlots(unsigned &NumEntries) const { - NumEntries = 0; - return nullptr; - } - - /// targetHandlesStackFrameRounding - Returns true if the target is - /// responsible for rounding up the stack frame (probably at emitPrologue - /// time). - virtual bool targetHandlesStackFrameRounding() const { - return false; - } - - /// Returns true if the target will correctly handle shrink wrapping. - virtual bool enableShrinkWrapping(const MachineFunction &MF) const { - return false; - } - - /// 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 enableStackSlotScavenging(const MachineFunction &MF) const { - return false; - } - - /// emitProlog/emitEpilog - These methods insert prolog and epilog code into - /// the function. - virtual void emitPrologue(MachineFunction &MF, - MachineBasicBlock &MBB) const = 0; - virtual void emitEpilogue(MachineFunction &MF, - MachineBasicBlock &MBB) const = 0; - - /// Replace a StackProbe stub (if any) with the actual probe code inline - virtual void inlineStackProbe(MachineFunction &MF, - MachineBasicBlock &PrologueMBB) const {} - - /// Adjust the prologue to have the function use segmented stacks. This works - /// by adding a check even before the "normal" function prologue. - virtual void adjustForSegmentedStacks(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 void adjustForHiPEPrologue(MachineFunction &MF, - MachineBasicBlock &PrologueMBB) 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(). Returns false otherwise. - virtual bool spillCalleeSavedRegisters(MachineBasicBlock &MBB, - MachineBasicBlock::iterator MI, - const std::vector<CalleeSavedInfo> &CSI, - const TargetRegisterInfo *TRI) const { - return false; - } - - /// 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. - virtual bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB, - MachineBasicBlock::iterator MI, - std::vector<CalleeSavedInfo> &CSI, - const TargetRegisterInfo *TRI) const { - return false; - } - - /// Return true if the target needs to disable frame pointer elimination. - virtual bool noFramePointerElim(const MachineFunction &MF) const; - - /// 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. - virtual bool hasFP(const MachineFunction &MF) const = 0; - - /// 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. - virtual bool hasReservedCallFrame(const MachineFunction &MF) const { - return !hasFP(MF); - } - - /// 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. - virtual bool canSimplifyCallFramePseudos(const MachineFunction &MF) const { - return hasReservedCallFrame(MF) || hasFP(MF); - } - - // needsFrameIndexResolution - Do we need to perform FI resolution for - // this function. Normally, this is required only when the function - // has any stack objects. However, targets may want to override this. - virtual bool needsFrameIndexResolution(const MachineFunction &MF) const; - - /// getFrameIndexReference - This method should return the base register - /// and offset used to reference a frame index location. The offset is - /// returned directly, and the base register is returned via FrameReg. - virtual int getFrameIndexReference(const MachineFunction &MF, int FI, - unsigned &FrameReg) const; - - /// Same as \c getFrameIndexReference, except that the stack pointer (as - /// opposed to the frame pointer) will be the preferred value for \p - /// FrameReg. This is generally used for emitting statepoint or EH tables that - /// use offsets from RSP. If \p IgnoreSPUpdates is true, the returned - /// offset is only guaranteed to be valid with respect to the value of SP at - /// the end of the prologue. - virtual int getFrameIndexReferencePreferSP(const MachineFunction &MF, int FI, - unsigned &FrameReg, - bool IgnoreSPUpdates) const { - // Always safe to dispatch to getFrameIndexReference. - return getFrameIndexReference(MF, FI, FrameReg); - } - - /// This method determines which of the registers reported by - /// TargetRegisterInfo::getCalleeSavedRegs() should actually get saved. - /// The default implementation checks populates the \p 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. - virtual void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs, - RegScavenger *RS = nullptr) const; - - /// processFunctionBeforeFrameFinalized - This method is called immediately - /// before the specified function's frame layout (MF.getFrameInfo()) is - /// finalized. Once the frame is finalized, MO_FrameIndex operands are - /// replaced with direct constants. This method is optional. - /// - virtual void processFunctionBeforeFrameFinalized(MachineFunction &MF, - RegScavenger *RS = nullptr) const { - } - - virtual unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const { - report_fatal_error("WinEH not implemented for this target"); - } - - /// 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. - virtual MachineBasicBlock::iterator - eliminateCallFramePseudoInstr(MachineFunction &MF, - MachineBasicBlock &MBB, - MachineBasicBlock::iterator MI) const { - llvm_unreachable("Call Frame Pseudo Instructions do not exist on this " - "target!"); - } - - - /// Order the symbols in the local stack frame. - /// The list of objects that we want to order is in \p objectsToAllocate as - /// indices into the MachineFrameInfo. The array can be reordered in any way - /// upon return. The contents of the array, however, may not be modified (i.e. - /// only their order may be changed). - /// By default, just maintain the original order. - virtual void - orderFrameObjects(const MachineFunction &MF, - SmallVectorImpl<int> &objectsToAllocate) const { - } - - /// Check whether or not the given \p MBB can be used as a prologue - /// for the target. - /// The prologue will be inserted first in this basic block. - /// This method is used by the shrink-wrapping pass to decide if - /// \p MBB will be correctly handled by the target. - /// As soon as the target enable shrink-wrapping without overriding - /// this method, we assume that each basic block is a valid - /// prologue. - virtual bool canUseAsPrologue(const MachineBasicBlock &MBB) const { - return true; - } - - /// Check whether or not the given \p MBB can be used as a epilogue - /// for the target. - /// The epilogue will be inserted before the first terminator of that block. - /// This method is used by the shrink-wrapping pass to decide if - /// \p MBB will be correctly handled by the target. - /// As soon as the target enable shrink-wrapping without overriding - /// this method, we assume that each basic block is a valid - /// epilogue. - virtual bool canUseAsEpilogue(const MachineBasicBlock &MBB) const { - return true; - } - - /// Check if given function is safe for not having callee saved registers. - /// This is used when interprocedural register allocation is enabled. - static bool isSafeForNoCSROpt(const Function *F) { - if (!F->hasLocalLinkage() || F->hasAddressTaken() || - !F->hasFnAttribute(Attribute::NoRecurse)) - return false; - // Function should not be optimized as tail call. - for (const User *U : F->users()) - if (auto CS = ImmutableCallSite(U)) - if (CS.isTailCall()) - return false; - return true; - } -}; - -} // End llvm namespace - -#endif |