//===-- llvm/Target/TargetFrameInfo.h ---------------------------*- C++ -*-===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// 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_TARGETFRAMEINFO_H
#define LLVM_TARGET_TARGETFRAMEINFO_H
-namespace llvm {
+#include <utility>
+#include <vector>
-class MachineFunction;
+namespace llvm {
+ class MachineFunction;
+ class MachineBasicBlock;
+ class MachineMove;
-struct TargetFrameInfo {
+/// 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 TargetFrameInfo {
+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;
public:
- TargetFrameInfo(StackDirection D, unsigned StackAl, int LAO)
- : StackDir(D), StackAlignment(StackAl), LocalAreaOffset(LAO) {}
+ TargetFrameInfo(StackDirection D, unsigned StackAl, int LAO,
+ unsigned TransAl = 1)
+ : StackDir(D), StackAlignment(StackAl), TransientStackAlignment(TransAl),
+ LocalAreaOffset(LAO) {}
+
+ virtual ~TargetFrameInfo();
// These methods return information that describes the abstract stack layout
// of the target machine.
///
StackDirection getStackGrowthDirection() const { return StackDir; }
- /// getStackAlignment - This method returns the number of bytes that the stack
- /// pointer must be aligned to. Typically, this is the largest alignment for
- /// any data object in the target.
+ /// 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; }
+ /// 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;
+ }
+
/// getOffsetOfLocalArea - This method returns the offset of the local area
/// from the stack pointer on entrance to a function.
///
int getOffsetOfLocalArea() const { return LocalAreaOffset; }
- //===--------------------------------------------------------------------===//
- // These methods provide details of the stack frame used by Sparc, thus they
- // are Sparc specific.
- //===--------------------------------------------------------------------===//
-
- virtual int getStackFrameSizeAlignment () const;
- virtual int getMinStackFrameSize () const;
- virtual int getNumFixedOutgoingArgs () const;
- virtual int getSizeOfEachArgOnStack () const;
- virtual bool argsOnStackHaveFixedSize () const;
-
- // This method adjusts a stack offset to meet alignment rules of target.
- virtual int adjustAlignment(int unalignedOffset, bool growUp,
- unsigned align) const;
-
- // These methods compute offsets using the frame contents for a particular
- // function. The frame contents are obtained from the MachineFunction object
- // for the given function. The rest must be implemented by the
- // machine-specific subclass.
- //
- virtual int getIncomingArgOffset (MachineFunction& mcInfo,
- unsigned argNum) const;
- virtual int getOutgoingArgOffset (MachineFunction& mcInfo,
- unsigned argNum) const;
-
- virtual int getFirstIncomingArgOffset (MachineFunction& mcInfo,
- bool& growUp) const;
- virtual int getFirstOutgoingArgOffset (MachineFunction& mcInfo,
- bool& growUp) const;
- virtual int getFirstOptionalOutgoingArgOffset (MachineFunction&,
- bool& growUp) const;
- virtual int getFirstAutomaticVarOffset (MachineFunction& mcInfo,
- bool& growUp) const;
- virtual int getRegSpillAreaOffset (MachineFunction& mcInfo,
- bool& growUp) const;
- virtual int getTmpAreaOffset (MachineFunction& mcInfo,
- bool& growUp) const;
- virtual int getDynamicAreaOffset (MachineFunction& mcInfo,
- bool& growUp) const;
-
- //
- // These methods specify the base register used for each stack area
- // (generally FP or SP)
- //
- virtual int getIncomingArgBaseRegNum() const;
- virtual int getOutgoingArgBaseRegNum() const;
- virtual int getOptionalOutgoingArgBaseRegNum() const;
- virtual int getAutomaticVarBaseRegNum() const;
- virtual int getRegSpillAreaBaseRegNum() const;
- virtual int getDynamicAreaBaseRegNum() 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.
+ ///
+ /// 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 0;
+ }
+
+ /// targetHandlesStackFrameRounding - Returns true if the target is
+ /// responsible for rounding up the stack frame (probably at emitPrologue
+ /// time).
+ virtual bool targetHandlesStackFrameRounding() const {
+ return false;
+ }
+
+ /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
+ /// the function.
+ virtual void emitPrologue(MachineFunction &MF) const = 0;
+ virtual void emitEpilogue(MachineFunction &MF,
+ MachineBasicBlock &MBB) const = 0;
+
+ /// 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);
+ }
+
+ /// getInitialFrameState - Returns a list of machine moves that are assumed
+ /// on entry to all functions. Note that LabelID is ignored (assumed to be
+ /// the beginning of the function.)
+ virtual void getInitialFrameState(std::vector<MachineMove> &Moves) const;
+
+ /// getFrameIndexOffset - Returns the displacement from the frame register to
+ /// the stack frame of the specified index.
+ virtual int getFrameIndexOffset(const MachineFunction &MF, int FI) 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;
};
} // End llvm namespace
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