1 //===-- PPCFrameInfo.h - Define TargetFrameInfo for PowerPC -----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 //===----------------------------------------------------------------------===//
13 #ifndef POWERPC_FRAMEINFO_H
14 #define POWERPC_FRAMEINFO_H
17 #include "llvm/Target/TargetFrameInfo.h"
18 #include "llvm/Target/TargetMachine.h"
22 class PPCFrameInfo: public TargetFrameInfo {
23 const TargetMachine &TM;
26 PPCFrameInfo(const TargetMachine &tm, bool LP64)
27 : TargetFrameInfo(TargetFrameInfo::StackGrowsDown, 16, 0), TM(tm) {
30 /// getReturnSaveOffset - Return the previous frame offset to save the
32 static unsigned getReturnSaveOffset(bool LP64) {
36 /// getFramePointerSaveOffset - Return the previous frame offset to save the
38 static unsigned getFramePointerSaveOffset(bool LP64) {
39 // Use the TOC save slot in the PowerPC linkage area for saving the frame
40 // pointer (if needed.) LLVM does not generate code that uses the TOC (R2
41 // is treated as a caller saved register.)
42 return LP64 ? 40 : 20;
45 /// getLinkageSize - Return the size of the PowerPC ABI linkage area.
47 static unsigned getLinkageSize(bool LP64) {
48 return 6 * (LP64 ? 8 : 4);
51 /// getMinCallArgumentsSize - Return the size of the minium PowerPC ABI
53 static unsigned getMinCallArgumentsSize(bool LP64) {
54 // The prolog code of the callee may store up to 8 GPR argument registers to
55 // the stack, allowing va_start to index over them in memory if its varargs.
56 // Because we cannot tell if this is needed on the caller side, we have to
57 // conservatively assume that it is needed. As such, make sure we have at
58 // least enough stack space for the caller to store the 8 GPRs.
59 return 8 * (LP64 ? 8 : 4);
62 /// getMinCallFrameSize - Return the minimum size a call frame can be using
64 static unsigned getMinCallFrameSize(bool LP64) {
65 // The call frame needs to be at least big enough for linkage and 8 args.
66 return getLinkageSize(LP64) + getMinCallArgumentsSize(LP64);
71 } // End llvm namespace