| //===-- CodeGen/MachineFrameInfo.h - Abstract Stack Frame Rep. --*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // The file defines the MachineFrameInfo class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CODEGEN_MACHINEFRAMEINFO_H |
| #define LLVM_CODEGEN_MACHINEFRAMEINFO_H |
| |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/Support/DataTypes.h" |
| #include <cassert> |
| #include <vector> |
| |
| namespace llvm { |
| class raw_ostream; |
| class MachineFunction; |
| class MachineBasicBlock; |
| class BitVector; |
| class AllocaInst; |
| |
| /// The CalleeSavedInfo class tracks the information need to locate where a |
| /// callee saved register is in the current frame. |
| /// Callee saved reg can also be saved to a different register rather than |
| /// on the stack by setting DstReg instead of FrameIdx. |
| class CalleeSavedInfo { |
| unsigned Reg; |
| union { |
| int FrameIdx; |
| unsigned DstReg; |
| }; |
| /// Flag indicating whether the register is actually restored in the epilog. |
| /// In most cases, if a register is saved, it is also restored. There are |
| /// some situations, though, when this is not the case. For example, the |
| /// LR register on ARM is usually saved, but on exit from the function its |
| /// saved value may be loaded directly into PC. Since liveness tracking of |
| /// physical registers treats callee-saved registers are live outside of |
| /// the function, LR would be treated as live-on-exit, even though in these |
| /// scenarios it is not. This flag is added to indicate that the saved |
| /// register described by this object is not restored in the epilog. |
| /// The long-term solution is to model the liveness of callee-saved registers |
| /// by implicit uses on the return instructions, however, the required |
| /// changes in the ARM backend would be quite extensive. |
| bool Restored; |
| /// Flag indicating whether the register is spilled to stack or another |
| /// register. |
| bool SpilledToReg; |
| |
| public: |
| explicit CalleeSavedInfo(unsigned R, int FI = 0) |
| : Reg(R), FrameIdx(FI), Restored(true), SpilledToReg(false) {} |
| |
| // Accessors. |
| unsigned getReg() const { return Reg; } |
| int getFrameIdx() const { return FrameIdx; } |
| unsigned getDstReg() const { return DstReg; } |
| void setFrameIdx(int FI) { |
| FrameIdx = FI; |
| SpilledToReg = false; |
| } |
| void setDstReg(unsigned SpillReg) { |
| DstReg = SpillReg; |
| SpilledToReg = true; |
| } |
| bool isRestored() const { return Restored; } |
| void setRestored(bool R) { Restored = R; } |
| bool isSpilledToReg() const { return SpilledToReg; } |
| }; |
| |
| /// The MachineFrameInfo class represents an abstract stack frame until |
| /// prolog/epilog code is inserted. This class is key to allowing stack frame |
| /// representation optimizations, such as frame pointer elimination. It also |
| /// allows more mundane (but still important) optimizations, such as reordering |
| /// of abstract objects on the stack frame. |
| /// |
| /// To support this, the class assigns unique integer identifiers to stack |
| /// objects requested clients. These identifiers are negative integers for |
| /// fixed stack objects (such as arguments passed on the stack) or nonnegative |
| /// for objects that may be reordered. Instructions which refer to stack |
| /// objects use a special MO_FrameIndex operand to represent these frame |
| /// indexes. |
| /// |
| /// Because this class keeps track of all references to the stack frame, it |
| /// knows when a variable sized object is allocated on the stack. This is the |
| /// sole condition which prevents frame pointer elimination, which is an |
| /// important optimization on register-poor architectures. Because original |
| /// variable sized alloca's in the source program are the only source of |
| /// variable sized stack objects, it is safe to decide whether there will be |
| /// any variable sized objects before all stack objects are known (for |
| /// example, register allocator spill code never needs variable sized |
| /// objects). |
| /// |
| /// When prolog/epilog code emission is performed, the final stack frame is |
| /// built and the machine instructions are modified to refer to the actual |
| /// stack offsets of the object, eliminating all MO_FrameIndex operands from |
| /// the program. |
| /// |
| /// Abstract Stack Frame Information |
| class MachineFrameInfo { |
| public: |
| /// Stack Smashing Protection (SSP) rules require that vulnerable stack |
| /// allocations are located close the stack protector. |
| enum SSPLayoutKind { |
| SSPLK_None, ///< Did not trigger a stack protector. No effect on data |
| ///< layout. |
| SSPLK_LargeArray, ///< Array or nested array >= SSP-buffer-size. Closest |
| ///< to the stack protector. |
| SSPLK_SmallArray, ///< Array or nested array < SSP-buffer-size. 2nd closest |
| ///< to the stack protector. |
| SSPLK_AddrOf ///< The address of this allocation is exposed and |
| ///< triggered protection. 3rd closest to the protector. |
| }; |
| |
| private: |
| // Represent a single object allocated on the stack. |
| struct StackObject { |
| // The offset of this object from the stack pointer on entry to |
| // the function. This field has no meaning for a variable sized element. |
| int64_t SPOffset; |
| |
| // The size of this object on the stack. 0 means a variable sized object, |
| // ~0ULL means a dead object. |
| uint64_t Size; |
| |
| // The required alignment of this stack slot. |
| unsigned Alignment; |
| |
| // If true, the value of the stack object is set before |
| // entering the function and is not modified inside the function. By |
| // default, fixed objects are immutable unless marked otherwise. |
| bool isImmutable; |
| |
| // If true the stack object is used as spill slot. It |
| // cannot alias any other memory objects. |
| bool isSpillSlot; |
| |
| /// If true, this stack slot is used to spill a value (could be deopt |
| /// and/or GC related) over a statepoint. We know that the address of the |
| /// slot can't alias any LLVM IR value. This is very similar to a Spill |
| /// Slot, but is created by statepoint lowering is SelectionDAG, not the |
| /// register allocator. |
| bool isStatepointSpillSlot = false; |
| |
| /// Identifier for stack memory type analagous to address space. If this is |
| /// non-0, the meaning is target defined. Offsets cannot be directly |
| /// compared between objects with different stack IDs. The object may not |
| /// necessarily reside in the same contiguous memory block as other stack |
| /// objects. Objects with differing stack IDs should not be merged or |
| /// replaced substituted for each other. |
| // |
| /// It is assumed a target uses consecutive, increasing stack IDs starting |
| /// from 1. |
| uint8_t StackID; |
| |
| /// If this stack object is originated from an Alloca instruction |
| /// this value saves the original IR allocation. Can be NULL. |
| const AllocaInst *Alloca; |
| |
| // If true, the object was mapped into the local frame |
| // block and doesn't need additional handling for allocation beyond that. |
| bool PreAllocated = false; |
| |
| // If true, an LLVM IR value might point to this object. |
| // Normally, spill slots and fixed-offset objects don't alias IR-accessible |
| // objects, but there are exceptions (on PowerPC, for example, some byval |
| // arguments have ABI-prescribed offsets). |
| bool isAliased; |
| |
| /// If true, the object has been zero-extended. |
| bool isZExt = false; |
| |
| /// If true, the object has been zero-extended. |
| bool isSExt = false; |
| |
| uint8_t SSPLayout; |
| |
| StackObject(uint64_t Size, unsigned Alignment, int64_t SPOffset, |
| bool IsImmutable, bool IsSpillSlot, const AllocaInst *Alloca, |
| bool IsAliased, uint8_t StackID = 0) |
| : SPOffset(SPOffset), Size(Size), Alignment(Alignment), |
| isImmutable(IsImmutable), isSpillSlot(IsSpillSlot), |
| StackID(StackID), Alloca(Alloca), isAliased(IsAliased), |
| SSPLayout(SSPLK_None) {} |
| }; |
| |
| /// The alignment of the stack. |
| unsigned StackAlignment; |
| |
| /// Can the stack be realigned. This can be false if the target does not |
| /// support stack realignment, or if the user asks us not to realign the |
| /// stack. In this situation, overaligned allocas are all treated as dynamic |
| /// allocations and the target must handle them as part of DYNAMIC_STACKALLOC |
| /// lowering. All non-alloca stack objects have their alignment clamped to the |
| /// base ABI stack alignment. |
| /// FIXME: There is room for improvement in this case, in terms of |
| /// grouping overaligned allocas into a "secondary stack frame" and |
| /// then only use a single alloca to allocate this frame and only a |
| /// single virtual register to access it. Currently, without such an |
| /// optimization, each such alloca gets its own dynamic realignment. |
| bool StackRealignable; |
| |
| /// Whether the function has the \c alignstack attribute. |
| bool ForcedRealign; |
| |
| /// The list of stack objects allocated. |
| std::vector<StackObject> Objects; |
| |
| /// This contains the number of fixed objects contained on |
| /// the stack. Because fixed objects are stored at a negative index in the |
| /// Objects list, this is also the index to the 0th object in the list. |
| unsigned NumFixedObjects = 0; |
| |
| /// This boolean keeps track of whether any variable |
| /// sized objects have been allocated yet. |
| bool HasVarSizedObjects = false; |
| |
| /// This boolean keeps track of whether there is a call |
| /// to builtin \@llvm.frameaddress. |
| bool FrameAddressTaken = false; |
| |
| /// This boolean keeps track of whether there is a call |
| /// to builtin \@llvm.returnaddress. |
| bool ReturnAddressTaken = false; |
| |
| /// This boolean keeps track of whether there is a call |
| /// to builtin \@llvm.experimental.stackmap. |
| bool HasStackMap = false; |
| |
| /// This boolean keeps track of whether there is a call |
| /// to builtin \@llvm.experimental.patchpoint. |
| bool HasPatchPoint = false; |
| |
| /// The prolog/epilog code inserter calculates the final stack |
| /// offsets for all of the fixed size objects, updating the Objects list |
| /// above. It then updates StackSize to contain the number of bytes that need |
| /// to be allocated on entry to the function. |
| uint64_t StackSize = 0; |
| |
| /// The amount that a frame offset needs to be adjusted to |
| /// have the actual offset from the stack/frame pointer. The exact usage of |
| /// this is target-dependent, but it is typically used to adjust between |
| /// SP-relative and FP-relative offsets. E.G., if objects are accessed via |
| /// SP then OffsetAdjustment is zero; if FP is used, OffsetAdjustment is set |
| /// to the distance between the initial SP and the value in FP. For many |
| /// targets, this value is only used when generating debug info (via |
| /// TargetRegisterInfo::getFrameIndexReference); when generating code, the |
| /// corresponding adjustments are performed directly. |
| int OffsetAdjustment = 0; |
| |
| /// The prolog/epilog code inserter may process objects that require greater |
| /// alignment than the default alignment the target provides. |
| /// To handle this, MaxAlignment is set to the maximum alignment |
| /// needed by the objects on the current frame. If this is greater than the |
| /// native alignment maintained by the compiler, dynamic alignment code will |
| /// be needed. |
| /// |
| unsigned MaxAlignment = 0; |
| |
| /// Set to true if this function adjusts the stack -- e.g., |
| /// when calling another function. This is only valid during and after |
| /// prolog/epilog code insertion. |
| bool AdjustsStack = false; |
| |
| /// Set to true if this function has any function calls. |
| bool HasCalls = false; |
| |
| /// The frame index for the stack protector. |
| int StackProtectorIdx = -1; |
| |
| /// The frame index for the function context. Used for SjLj exceptions. |
| int FunctionContextIdx = -1; |
| |
| /// This contains the size of the largest call frame if the target uses frame |
| /// setup/destroy pseudo instructions (as defined in the TargetFrameInfo |
| /// class). This information is important for frame pointer elimination. |
| /// It is only valid during and after prolog/epilog code insertion. |
| unsigned MaxCallFrameSize = ~0u; |
| |
| /// The number of bytes of callee saved registers that the target wants to |
| /// report for the current function in the CodeView S_FRAMEPROC record. |
| unsigned CVBytesOfCalleeSavedRegisters = 0; |
| |
| /// The prolog/epilog code inserter fills in this vector with each |
| /// callee saved register saved in either the frame or a different |
| /// register. Beyond its use by the prolog/ epilog code inserter, |
| /// this data is used for debug info and exception handling. |
| std::vector<CalleeSavedInfo> CSInfo; |
| |
| /// Has CSInfo been set yet? |
| bool CSIValid = false; |
| |
| /// References to frame indices which are mapped |
| /// into the local frame allocation block. <FrameIdx, LocalOffset> |
| SmallVector<std::pair<int, int64_t>, 32> LocalFrameObjects; |
| |
| /// Size of the pre-allocated local frame block. |
| int64_t LocalFrameSize = 0; |
| |
| /// Required alignment of the local object blob, which is the strictest |
| /// alignment of any object in it. |
| unsigned LocalFrameMaxAlign = 0; |
| |
| /// Whether the local object blob needs to be allocated together. If not, |
| /// PEI should ignore the isPreAllocated flags on the stack objects and |
| /// just allocate them normally. |
| bool UseLocalStackAllocationBlock = false; |
| |
| /// True if the function dynamically adjusts the stack pointer through some |
| /// opaque mechanism like inline assembly or Win32 EH. |
| bool HasOpaqueSPAdjustment = false; |
| |
| /// True if the function contains operations which will lower down to |
| /// instructions which manipulate the stack pointer. |
| bool HasCopyImplyingStackAdjustment = false; |
| |
| /// True if the function contains a call to the llvm.vastart intrinsic. |
| bool HasVAStart = false; |
| |
| /// True if this is a varargs function that contains a musttail call. |
| bool HasMustTailInVarArgFunc = false; |
| |
| /// True if this function contains a tail call. If so immutable objects like |
| /// function arguments are no longer so. A tail call *can* override fixed |
| /// stack objects like arguments so we can't treat them as immutable. |
| bool HasTailCall = false; |
| |
| /// Not null, if shrink-wrapping found a better place for the prologue. |
| MachineBasicBlock *Save = nullptr; |
| /// Not null, if shrink-wrapping found a better place for the epilogue. |
| MachineBasicBlock *Restore = nullptr; |
| |
| public: |
| explicit MachineFrameInfo(unsigned StackAlignment, bool StackRealignable, |
| bool ForcedRealign) |
| : StackAlignment(StackAlignment), StackRealignable(StackRealignable), |
| ForcedRealign(ForcedRealign) {} |
| |
| /// Return true if there are any stack objects in this function. |
| bool hasStackObjects() const { return !Objects.empty(); } |
| |
| /// This method may be called any time after instruction |
| /// selection is complete to determine if the stack frame for this function |
| /// contains any variable sized objects. |
| bool hasVarSizedObjects() const { return HasVarSizedObjects; } |
| |
| /// Return the index for the stack protector object. |
| int getStackProtectorIndex() const { return StackProtectorIdx; } |
| void setStackProtectorIndex(int I) { StackProtectorIdx = I; } |
| bool hasStackProtectorIndex() const { return StackProtectorIdx != -1; } |
| |
| /// Return the index for the function context object. |
| /// This object is used for SjLj exceptions. |
| int getFunctionContextIndex() const { return FunctionContextIdx; } |
| void setFunctionContextIndex(int I) { FunctionContextIdx = I; } |
| |
| /// This method may be called any time after instruction |
| /// selection is complete to determine if there is a call to |
| /// \@llvm.frameaddress in this function. |
| bool isFrameAddressTaken() const { return FrameAddressTaken; } |
| void setFrameAddressIsTaken(bool T) { FrameAddressTaken = T; } |
| |
| /// This method may be called any time after |
| /// instruction selection is complete to determine if there is a call to |
| /// \@llvm.returnaddress in this function. |
| bool isReturnAddressTaken() const { return ReturnAddressTaken; } |
| void setReturnAddressIsTaken(bool s) { ReturnAddressTaken = s; } |
| |
| /// This method may be called any time after instruction |
| /// selection is complete to determine if there is a call to builtin |
| /// \@llvm.experimental.stackmap. |
| bool hasStackMap() const { return HasStackMap; } |
| void setHasStackMap(bool s = true) { HasStackMap = s; } |
| |
| /// This method may be called any time after instruction |
| /// selection is complete to determine if there is a call to builtin |
| /// \@llvm.experimental.patchpoint. |
| bool hasPatchPoint() const { return HasPatchPoint; } |
| void setHasPatchPoint(bool s = true) { HasPatchPoint = s; } |
| |
| /// Return the minimum frame object index. |
| int getObjectIndexBegin() const { return -NumFixedObjects; } |
| |
| /// Return one past the maximum frame object index. |
| int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; } |
| |
| /// Return the number of fixed objects. |
| unsigned getNumFixedObjects() const { return NumFixedObjects; } |
| |
| /// Return the number of objects. |
| unsigned getNumObjects() const { return Objects.size(); } |
| |
| /// Map a frame index into the local object block |
| void mapLocalFrameObject(int ObjectIndex, int64_t Offset) { |
| LocalFrameObjects.push_back(std::pair<int, int64_t>(ObjectIndex, Offset)); |
| Objects[ObjectIndex + NumFixedObjects].PreAllocated = true; |
| } |
| |
| /// Get the local offset mapping for a for an object. |
| std::pair<int, int64_t> getLocalFrameObjectMap(int i) const { |
| assert (i >= 0 && (unsigned)i < LocalFrameObjects.size() && |
| "Invalid local object reference!"); |
| return LocalFrameObjects[i]; |
| } |
| |
| /// Return the number of objects allocated into the local object block. |
| int64_t getLocalFrameObjectCount() const { return LocalFrameObjects.size(); } |
| |
| /// Set the size of the local object blob. |
| void setLocalFrameSize(int64_t sz) { LocalFrameSize = sz; } |
| |
| /// Get the size of the local object blob. |
| int64_t getLocalFrameSize() const { return LocalFrameSize; } |
| |
| /// Required alignment of the local object blob, |
| /// which is the strictest alignment of any object in it. |
| void setLocalFrameMaxAlign(unsigned Align) { LocalFrameMaxAlign = Align; } |
| |
| /// Return the required alignment of the local object blob. |
| unsigned getLocalFrameMaxAlign() const { return LocalFrameMaxAlign; } |
| |
| /// Get whether the local allocation blob should be allocated together or |
| /// let PEI allocate the locals in it directly. |
| bool getUseLocalStackAllocationBlock() const { |
| return UseLocalStackAllocationBlock; |
| } |
| |
| /// setUseLocalStackAllocationBlock - Set whether the local allocation blob |
| /// should be allocated together or let PEI allocate the locals in it |
| /// directly. |
| void setUseLocalStackAllocationBlock(bool v) { |
| UseLocalStackAllocationBlock = v; |
| } |
| |
| /// Return true if the object was pre-allocated into the local block. |
| bool isObjectPreAllocated(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].PreAllocated; |
| } |
| |
| /// Return the size of the specified object. |
| int64_t getObjectSize(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].Size; |
| } |
| |
| /// Change the size of the specified stack object. |
| void setObjectSize(int ObjectIdx, int64_t Size) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| Objects[ObjectIdx+NumFixedObjects].Size = Size; |
| } |
| |
| /// Return the alignment of the specified stack object. |
| unsigned getObjectAlignment(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].Alignment; |
| } |
| |
| /// setObjectAlignment - Change the alignment of the specified stack object. |
| void setObjectAlignment(int ObjectIdx, unsigned Align) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| Objects[ObjectIdx+NumFixedObjects].Alignment = Align; |
| ensureMaxAlignment(Align); |
| } |
| |
| /// Return the underlying Alloca of the specified |
| /// stack object if it exists. Returns 0 if none exists. |
| const AllocaInst* getObjectAllocation(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].Alloca; |
| } |
| |
| /// Return the assigned stack offset of the specified object |
| /// from the incoming stack pointer. |
| int64_t getObjectOffset(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| assert(!isDeadObjectIndex(ObjectIdx) && |
| "Getting frame offset for a dead object?"); |
| return Objects[ObjectIdx+NumFixedObjects].SPOffset; |
| } |
| |
| bool isObjectZExt(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].isZExt; |
| } |
| |
| void setObjectZExt(int ObjectIdx, bool IsZExt) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| Objects[ObjectIdx+NumFixedObjects].isZExt = IsZExt; |
| } |
| |
| bool isObjectSExt(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].isSExt; |
| } |
| |
| void setObjectSExt(int ObjectIdx, bool IsSExt) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| Objects[ObjectIdx+NumFixedObjects].isSExt = IsSExt; |
| } |
| |
| /// Set the stack frame offset of the specified object. The |
| /// offset is relative to the stack pointer on entry to the function. |
| void setObjectOffset(int ObjectIdx, int64_t SPOffset) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| assert(!isDeadObjectIndex(ObjectIdx) && |
| "Setting frame offset for a dead object?"); |
| Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset; |
| } |
| |
| SSPLayoutKind getObjectSSPLayout(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return (SSPLayoutKind)Objects[ObjectIdx+NumFixedObjects].SSPLayout; |
| } |
| |
| void setObjectSSPLayout(int ObjectIdx, SSPLayoutKind Kind) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| assert(!isDeadObjectIndex(ObjectIdx) && |
| "Setting SSP layout for a dead object?"); |
| Objects[ObjectIdx+NumFixedObjects].SSPLayout = Kind; |
| } |
| |
| /// Return the number of bytes that must be allocated to hold |
| /// all of the fixed size frame objects. This is only valid after |
| /// Prolog/Epilog code insertion has finalized the stack frame layout. |
| uint64_t getStackSize() const { return StackSize; } |
| |
| /// Set the size of the stack. |
| void setStackSize(uint64_t Size) { StackSize = Size; } |
| |
| /// Estimate and return the size of the stack frame. |
| unsigned estimateStackSize(const MachineFunction &MF) const; |
| |
| /// Return the correction for frame offsets. |
| int getOffsetAdjustment() const { return OffsetAdjustment; } |
| |
| /// Set the correction for frame offsets. |
| void setOffsetAdjustment(int Adj) { OffsetAdjustment = Adj; } |
| |
| /// Return the alignment in bytes that this function must be aligned to, |
| /// which is greater than the default stack alignment provided by the target. |
| unsigned getMaxAlignment() const { return MaxAlignment; } |
| |
| /// Make sure the function is at least Align bytes aligned. |
| void ensureMaxAlignment(unsigned Align); |
| |
| /// Return true if this function adjusts the stack -- e.g., |
| /// when calling another function. This is only valid during and after |
| /// prolog/epilog code insertion. |
| bool adjustsStack() const { return AdjustsStack; } |
| void setAdjustsStack(bool V) { AdjustsStack = V; } |
| |
| /// Return true if the current function has any function calls. |
| bool hasCalls() const { return HasCalls; } |
| void setHasCalls(bool V) { HasCalls = V; } |
| |
| /// Returns true if the function contains opaque dynamic stack adjustments. |
| bool hasOpaqueSPAdjustment() const { return HasOpaqueSPAdjustment; } |
| void setHasOpaqueSPAdjustment(bool B) { HasOpaqueSPAdjustment = B; } |
| |
| /// Returns true if the function contains operations which will lower down to |
| /// instructions which manipulate the stack pointer. |
| bool hasCopyImplyingStackAdjustment() const { |
| return HasCopyImplyingStackAdjustment; |
| } |
| void setHasCopyImplyingStackAdjustment(bool B) { |
| HasCopyImplyingStackAdjustment = B; |
| } |
| |
| /// Returns true if the function calls the llvm.va_start intrinsic. |
| bool hasVAStart() const { return HasVAStart; } |
| void setHasVAStart(bool B) { HasVAStart = B; } |
| |
| /// Returns true if the function is variadic and contains a musttail call. |
| bool hasMustTailInVarArgFunc() const { return HasMustTailInVarArgFunc; } |
| void setHasMustTailInVarArgFunc(bool B) { HasMustTailInVarArgFunc = B; } |
| |
| /// Returns true if the function contains a tail call. |
| bool hasTailCall() const { return HasTailCall; } |
| void setHasTailCall() { HasTailCall = true; } |
| |
| /// Computes the maximum size of a callframe and the AdjustsStack property. |
| /// This only works for targets defining |
| /// TargetInstrInfo::getCallFrameSetupOpcode(), getCallFrameDestroyOpcode(), |
| /// and getFrameSize(). |
| /// This is usually computed by the prologue epilogue inserter but some |
| /// targets may call this to compute it earlier. |
| void computeMaxCallFrameSize(const MachineFunction &MF); |
| |
| /// Return the maximum size of a call frame that must be |
| /// allocated for an outgoing function call. This is only available if |
| /// CallFrameSetup/Destroy pseudo instructions are used by the target, and |
| /// then only during or after prolog/epilog code insertion. |
| /// |
| unsigned getMaxCallFrameSize() const { |
| // TODO: Enable this assert when targets are fixed. |
| //assert(isMaxCallFrameSizeComputed() && "MaxCallFrameSize not computed yet"); |
| if (!isMaxCallFrameSizeComputed()) |
| return 0; |
| return MaxCallFrameSize; |
| } |
| bool isMaxCallFrameSizeComputed() const { |
| return MaxCallFrameSize != ~0u; |
| } |
| void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; } |
| |
| /// Returns how many bytes of callee-saved registers the target pushed in the |
| /// prologue. Only used for debug info. |
| unsigned getCVBytesOfCalleeSavedRegisters() const { |
| return CVBytesOfCalleeSavedRegisters; |
| } |
| void setCVBytesOfCalleeSavedRegisters(unsigned S) { |
| CVBytesOfCalleeSavedRegisters = S; |
| } |
| |
| /// Create a new object at a fixed location on the stack. |
| /// All fixed objects should be created before other objects are created for |
| /// efficiency. By default, fixed objects are not pointed to by LLVM IR |
| /// values. This returns an index with a negative value. |
| int CreateFixedObject(uint64_t Size, int64_t SPOffset, bool IsImmutable, |
| bool isAliased = false); |
| |
| /// Create a spill slot at a fixed location on the stack. |
| /// Returns an index with a negative value. |
| int CreateFixedSpillStackObject(uint64_t Size, int64_t SPOffset, |
| bool IsImmutable = false); |
| |
| /// Returns true if the specified index corresponds to a fixed stack object. |
| bool isFixedObjectIndex(int ObjectIdx) const { |
| return ObjectIdx < 0 && (ObjectIdx >= -(int)NumFixedObjects); |
| } |
| |
| /// Returns true if the specified index corresponds |
| /// to an object that might be pointed to by an LLVM IR value. |
| bool isAliasedObjectIndex(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].isAliased; |
| } |
| |
| /// Returns true if the specified index corresponds to an immutable object. |
| bool isImmutableObjectIndex(int ObjectIdx) const { |
| // Tail calling functions can clobber their function arguments. |
| if (HasTailCall) |
| return false; |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].isImmutable; |
| } |
| |
| /// Marks the immutability of an object. |
| void setIsImmutableObjectIndex(int ObjectIdx, bool IsImmutable) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| Objects[ObjectIdx+NumFixedObjects].isImmutable = IsImmutable; |
| } |
| |
| /// Returns true if the specified index corresponds to a spill slot. |
| bool isSpillSlotObjectIndex(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].isSpillSlot; |
| } |
| |
| bool isStatepointSpillSlotObjectIndex(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot; |
| } |
| |
| /// \see StackID |
| uint8_t getStackID(int ObjectIdx) const { |
| return Objects[ObjectIdx+NumFixedObjects].StackID; |
| } |
| |
| /// \see StackID |
| void setStackID(int ObjectIdx, uint8_t ID) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| Objects[ObjectIdx+NumFixedObjects].StackID = ID; |
| } |
| |
| /// Returns true if the specified index corresponds to a dead object. |
| bool isDeadObjectIndex(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx+NumFixedObjects].Size == ~0ULL; |
| } |
| |
| /// Returns true if the specified index corresponds to a variable sized |
| /// object. |
| bool isVariableSizedObjectIndex(int ObjectIdx) const { |
| assert(unsigned(ObjectIdx + NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| return Objects[ObjectIdx + NumFixedObjects].Size == 0; |
| } |
| |
| void markAsStatepointSpillSlotObjectIndex(int ObjectIdx) { |
| assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && |
| "Invalid Object Idx!"); |
| Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot = true; |
| assert(isStatepointSpillSlotObjectIndex(ObjectIdx) && "inconsistent"); |
| } |
| |
| /// Create a new statically sized stack object, returning |
| /// a nonnegative identifier to represent it. |
| int CreateStackObject(uint64_t Size, unsigned Alignment, bool isSpillSlot, |
| const AllocaInst *Alloca = nullptr, uint8_t ID = 0); |
| |
| /// Create a new statically sized stack object that represents a spill slot, |
| /// returning a nonnegative identifier to represent it. |
| int CreateSpillStackObject(uint64_t Size, unsigned Alignment); |
| |
| /// Remove or mark dead a statically sized stack object. |
| void RemoveStackObject(int ObjectIdx) { |
| // Mark it dead. |
| Objects[ObjectIdx+NumFixedObjects].Size = ~0ULL; |
| } |
| |
| /// Notify the MachineFrameInfo object that a variable sized object has been |
| /// created. This must be created whenever a variable sized object is |
| /// created, whether or not the index returned is actually used. |
| int CreateVariableSizedObject(unsigned Alignment, const AllocaInst *Alloca); |
| |
| /// Returns a reference to call saved info vector for the current function. |
| const std::vector<CalleeSavedInfo> &getCalleeSavedInfo() const { |
| return CSInfo; |
| } |
| /// \copydoc getCalleeSavedInfo() |
| std::vector<CalleeSavedInfo> &getCalleeSavedInfo() { return CSInfo; } |
| |
| /// Used by prolog/epilog inserter to set the function's callee saved |
| /// information. |
| void setCalleeSavedInfo(const std::vector<CalleeSavedInfo> &CSI) { |
| CSInfo = CSI; |
| } |
| |
| /// Has the callee saved info been calculated yet? |
| bool isCalleeSavedInfoValid() const { return CSIValid; } |
| |
| void setCalleeSavedInfoValid(bool v) { CSIValid = v; } |
| |
| MachineBasicBlock *getSavePoint() const { return Save; } |
| void setSavePoint(MachineBasicBlock *NewSave) { Save = NewSave; } |
| MachineBasicBlock *getRestorePoint() const { return Restore; } |
| void setRestorePoint(MachineBasicBlock *NewRestore) { Restore = NewRestore; } |
| |
| /// Return a set of physical registers that are pristine. |
| /// |
| /// Pristine registers hold a value that is useless to the current function, |
| /// but that must be preserved - they are callee saved registers that are not |
| /// saved. |
| /// |
| /// Before the PrologueEpilogueInserter has placed the CSR spill code, this |
| /// method always returns an empty set. |
| BitVector getPristineRegs(const MachineFunction &MF) const; |
| |
| /// Used by the MachineFunction printer to print information about |
| /// stack objects. Implemented in MachineFunction.cpp. |
| void print(const MachineFunction &MF, raw_ostream &OS) const; |
| |
| /// dump - Print the function to stderr. |
| void dump(const MachineFunction &MF) const; |
| }; |
| |
| } // End llvm namespace |
| |
| #endif |