-//===-- llvm/CodeGen/MachineFrameInfo.h -------------------------*- C++ -*-===//
+//===-- llvm/Target/TargetFrameInfo.h ---------------------------*- C++ -*-===//
//
-// Interface to layout of stack frame on target machine.
+// 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_CODEGEN_FRAMEINFO_H
-#define LLVM_CODEGEN_FRAMEINFO_H
+#ifndef LLVM_TARGET_TARGETFRAMEINFO_H
+#define LLVM_TARGET_TARGETFRAMEINFO_H
+
+#include <utility>
-#include "Support/NonCopyable.h"
-#include <vector>
+namespace llvm {
-class MachineCodeForMethod;
-class TargetMachine;
+/// 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
+ };
-struct MachineFrameInfo : public NonCopyableV {
- const TargetMachine ⌖
-
+ // 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:
- MachineFrameInfo(const TargetMachine& tgt) : target(tgt) {}
-
- // These methods provide constant parameters of the frame layout.
- //
- virtual int getStackFrameSizeAlignment () const = 0;
- virtual int getMinStackFrameSize () const = 0;
- virtual int getNumFixedOutgoingArgs () const = 0;
- virtual int getSizeOfEachArgOnStack () const = 0;
- virtual bool argsOnStackHaveFixedSize () const = 0;
+ TargetFrameInfo(StackDirection D, unsigned StackAl, int LAO,
+ unsigned TransAl = 1)
+ : StackDir(D), StackAlignment(StackAl), TransientStackAlignment(TransAl),
+ LocalAreaOffset(LAO) {}
- // This method adjusts a stack offset to meet alignment rules of target.
- //
- virtual int adjustAlignment (int unalignedOffset,
- bool growUp,
- unsigned int align) const {
- return unalignedOffset + (growUp? +1:-1)*(unalignedOffset % align);
+ virtual ~TargetFrameInfo();
+
+ // 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;
}
- // These methods compute offsets using the frame contents for a
- // particular method. The frame contents are obtained from the
- // MachineCodeInfoForMethod object for the given method.
- // The first few methods have default machine-independent implementations.
- // The rest must be implemented by the machine-specific subclass.
- //
- virtual int getIncomingArgOffset (MachineCodeForMethod& mcInfo,
- unsigned argNum) const;
- virtual int getOutgoingArgOffset (MachineCodeForMethod& mcInfo,
- unsigned argNum) const;
-
- virtual int getFirstIncomingArgOffset (MachineCodeForMethod& mcInfo,
- bool& growUp) const=0;
- virtual int getFirstOutgoingArgOffset (MachineCodeForMethod& mcInfo,
- bool& growUp) const=0;
- virtual int getFirstOptionalOutgoingArgOffset (MachineCodeForMethod&,
- bool& growUp) const=0;
- virtual int getFirstAutomaticVarOffset (MachineCodeForMethod& mcInfo,
- bool& growUp) const=0;
- virtual int getRegSpillAreaOffset (MachineCodeForMethod& mcInfo,
- bool& growUp) const=0;
- virtual int getTmpAreaOffset (MachineCodeForMethod& mcInfo,
- bool& growUp) const=0;
- virtual int getDynamicAreaOffset (MachineCodeForMethod& mcInfo,
- bool& growUp) const=0;
+ /// 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 specify the base register used for each stack area
- // (generally FP or SP)
- //
- virtual int getIncomingArgBaseRegNum() const=0;
- virtual int getOutgoingArgBaseRegNum() const=0;
- virtual int getOptionalOutgoingArgBaseRegNum() const=0;
- virtual int getAutomaticVarBaseRegNum() const=0;
- virtual int getRegSpillAreaBaseRegNum() const=0;
- virtual int getDynamicAreaBaseRegNum() const=0;
+ /// 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;
+ }
};
+} // End llvm namespace
+
#endif
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