llvm-6502/lib/Target/PowerPC/PPCFrameInfo.h
2007-12-29 20:36:04 +00:00

94 lines
2.9 KiB
C++

//===-- PPCFrameInfo.h - Define TargetFrameInfo for PowerPC -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
#ifndef POWERPC_FRAMEINFO_H
#define POWERPC_FRAMEINFO_H
#include "PPC.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
namespace llvm {
class PPCFrameInfo: public TargetFrameInfo {
const TargetMachine &TM;
public:
PPCFrameInfo(const TargetMachine &tm, bool LP64)
: TargetFrameInfo(TargetFrameInfo::StackGrowsDown, 16, 0), TM(tm) {
}
/// getReturnSaveOffset - Return the previous frame offset to save the
/// return address.
static unsigned getReturnSaveOffset(bool LP64, bool isMacho) {
if (isMacho)
return LP64 ? 16 : 8;
// For ELF 32 ABI:
return 4;
}
/// getFramePointerSaveOffset - Return the previous frame offset to save the
/// frame pointer.
static unsigned getFramePointerSaveOffset(bool LP64, bool isMacho) {
// For MachO ABI:
// Use the TOC save slot in the PowerPC linkage area for saving the frame
// pointer (if needed.) LLVM does not generate code that uses the TOC (R2
// is treated as a caller saved register.)
if (isMacho)
return LP64 ? 40 : 20;
// For ELF 32 ABI:
// Save it right before the link register
return -4U;
}
/// getLinkageSize - Return the size of the PowerPC ABI linkage area.
///
static unsigned getLinkageSize(bool LP64, bool isMacho) {
if (isMacho)
return 6 * (LP64 ? 8 : 4);
// For ELF 32 ABI:
return 8;
}
/// getMinCallArgumentsSize - Return the size of the minium PowerPC ABI
/// argument area.
static unsigned getMinCallArgumentsSize(bool LP64, bool isMacho) {
// For Macho ABI:
// The prolog code of the callee may store up to 8 GPR argument registers to
// the stack, allowing va_start to index over them in memory if its varargs.
// Because we cannot tell if this is needed on the caller side, we have to
// conservatively assume that it is needed. As such, make sure we have at
// least enough stack space for the caller to store the 8 GPRs.
if (isMacho)
return 8 * (LP64 ? 8 : 4);
// For ELF 32 ABI:
// There is no default stack allocated for the 8 first GPR arguments.
return 0;
}
/// getMinCallFrameSize - Return the minimum size a call frame can be using
/// the PowerPC ABI.
static unsigned getMinCallFrameSize(bool LP64, bool isMacho) {
// The call frame needs to be at least big enough for linkage and 8 args.
return getLinkageSize(LP64, isMacho) +
getMinCallArgumentsSize(LP64, isMacho);
}
};
} // End llvm namespace
#endif