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llvm-mirror/include/llvm/CodeGen/MachineFrameInfo.h
Reid Kleckner 2a9d1489b6 [codeview] Emit S_FRAMEPROC and use S_DEFRANGE_FRAMEPOINTER_REL
Summary:
Before this change, LLVM would always describe locals on the stack as
being relative to some specific register, RSP, ESP, EBP, ESI, etc.
Variables in stack memory are pretty common, so there is a special
S_DEFRANGE_FRAMEPOINTER_REL symbol for them. This change uses it to
reduce the size of our debug info.

On top of the size savings, there are cases on 32-bit x86 where local
variables are addressed from ESP, but ESP changes across the function.
Unlike in DWARF, there is no FPO data to describe the stack adjustments
made to push arguments onto the stack and pop them off after the call,
which makes it hard for the debugger to find the local variables in
frames further up the stack.

To handle this, CodeView has a special VFRAME register, which
corresponds to the $T0 variable set by our FPO data in 32-bit.  Offsets
to local variables are instead relative to this value.

This is part of PR38857.

Reviewers: hans, zturner, javed.absar

Subscribers: aprantl, hiraditya, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D52217

llvm-svn: 343543
2018-10-01 21:59:45 +00:00

772 lines
32 KiB
C++

//===-- CodeGen/MachineFrameInfo.h - Abstract Stack Frame Rep. --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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.
class CalleeSavedInfo {
unsigned Reg;
int FrameIdx;
/// 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;
public:
explicit CalleeSavedInfo(unsigned R, int FI = 0)
: Reg(R), FrameIdx(FI), Restored(true) {}
// Accessors.
unsigned getReg() const { return Reg; }
int getFrameIdx() const { return FrameIdx; }
void setFrameIdx(int FI) { FrameIdx = FI; }
bool isRestored() const { return Restored; }
void setRestored(bool R) { Restored = R; }
};
/// 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 the frame. Beyond its use by the prolog/
/// epilog code inserter, this data 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