mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-30 21:29:28 +00:00
to TargetFrameLowering, where it belongs. Incidentally, this allows us to delete some duplicated (and slightly different!) code in TRI. There are potentially other layering problems that can be cleaned up as a result, or in a similar manner. The refactoring was OK'd by Anton Korobeynikov on llvmdev. Note: this touches the target interfaces, so out-of-tree targets may be affected. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175788 91177308-0d34-0410-b5e6-96231b3b80d8
219 lines
9.2 KiB
C++
219 lines
9.2 KiB
C++
//===-- 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 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; }
|
|
|
|
/// 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;
|
|
}
|
|
|
|
/// getOffsetOfLocalArea - This method returns the offset of the local area
|
|
/// from the stack pointer on entrance to a function.
|
|
///
|
|
int getOffsetOfLocalArea() const { return LocalAreaOffset; }
|
|
|
|
/// 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;
|
|
|
|
/// 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) 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) 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().
|
|
/// Returns false otherwise.
|
|
virtual bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
|
|
MachineBasicBlock::iterator MI,
|
|
const std::vector<CalleeSavedInfo> &CSI,
|
|
const TargetRegisterInfo *TRI) const {
|
|
return false;
|
|
}
|
|
|
|
/// 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);
|
|
}
|
|
|
|
/// 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;
|
|
|
|
/// processFunctionBeforeCalleeSavedScan - This method is called immediately
|
|
/// before PrologEpilogInserter scans the physical registers used to determine
|
|
/// what callee saved registers should be spilled. This method is optional.
|
|
virtual void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
|
|
RegScavenger *RS = NULL) 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) const {
|
|
}
|
|
|
|
/// eliminateCallFramePseudoInstr - 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.
|
|
///
|
|
virtual void
|
|
eliminateCallFramePseudoInstr(MachineFunction &MF,
|
|
MachineBasicBlock &MBB,
|
|
MachineBasicBlock::iterator MI) const {
|
|
llvm_unreachable("Call Frame Pseudo Instructions do not exist on this "
|
|
"target!");
|
|
}
|
|
};
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|