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llvm-mirror/lib/Target/PowerPC/PPCFrameLowering.h
Hal Finkel 79a33a00d6 PPC: Add base-pointer support to builtin setjmp/longjmp
First, this changes the base-pointer implementation to remove an unnecessary
complication (and one that is incompatible with how builtin SjLj is
implemented): instead of using r31 as the base pointer when it is not needed as
a frame pointer, now the base pointer will always be r30 when needed.

Second, we introduce another pseudo register, BP, which is used just like the FP
pseudo register to refer to the base register before we know for certain what
register it will be.

Third, we now save BP into the jmp_buf, and restore r30 from that slot in
longjmp.  If the function that called setjmp did not use a base pointer, then
r30 will be overwritten by the setjmp-calling-function's restore code. FP
restoration (which is restored into r31) works the same way.

llvm-svn: 186545
2013-07-17 23:50:51 +00:00

304 lines
9.2 KiB
C++

//===-- PPCFrameLowering.h - Define frame lowering 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 "PPCSubtarget.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetMachine.h"
namespace llvm {
class PPCSubtarget;
class PPCFrameLowering: public TargetFrameLowering {
const PPCSubtarget &Subtarget;
public:
PPCFrameLowering(const PPCSubtarget &sti)
: TargetFrameLowering(TargetFrameLowering::StackGrowsDown,
(sti.hasQPX() || sti.isBGQ()) ? 32 : 16, 0),
Subtarget(sti) {
}
unsigned determineFrameLayout(MachineFunction &MF,
bool UpdateMF = true,
bool UseEstimate = false) const;
/// emitProlog/emitEpilog - These methods insert prolog and epilog code into
/// the function.
void emitPrologue(MachineFunction &MF) const;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const;
bool hasFP(const MachineFunction &MF) const;
bool needsFP(const MachineFunction &MF) const;
void replaceFPWithRealFP(MachineFunction &MF) const;
void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS = NULL) const;
void processFunctionBeforeFrameFinalized(MachineFunction &MF,
RegScavenger *RS = NULL) const;
void addScavengingSpillSlot(MachineFunction &MF, RegScavenger *RS) const;
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const;
void eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const;
bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const;
/// targetHandlesStackFrameRounding - Returns true if the target is
/// responsible for rounding up the stack frame (probably at emitPrologue
/// time).
bool targetHandlesStackFrameRounding() const { return true; }
/// getReturnSaveOffset - Return the previous frame offset to save the
/// return address.
static unsigned getReturnSaveOffset(bool isPPC64, bool isDarwinABI) {
if (isDarwinABI)
return isPPC64 ? 16 : 8;
// SVR4 ABI:
return isPPC64 ? 16 : 4;
}
/// getFramePointerSaveOffset - Return the previous frame offset to save the
/// frame pointer.
static unsigned getFramePointerSaveOffset(bool isPPC64, bool isDarwinABI) {
// For the Darwin ABI:
// We cannot use the TOC save slot (offset +20) in the PowerPC linkage area
// for saving the frame pointer (if needed.) While the published ABI has
// not used this slot since at least MacOSX 10.2, there is older code
// around that does use it, and that needs to continue to work.
if (isDarwinABI)
return isPPC64 ? -8U : -4U;
// SVR4 ABI: First slot in the general register save area.
return isPPC64 ? -8U : -4U;
}
/// getBasePointerSaveOffset - Return the previous frame offset to save the
/// base pointer.
static unsigned getBasePointerSaveOffset(bool isPPC64, bool isDarwinABI) {
if (isDarwinABI)
return isPPC64 ? -16U : -8U;
// SVR4 ABI: First slot in the general register save area.
return isPPC64 ? -16U : -8U;
}
/// getLinkageSize - Return the size of the PowerPC ABI linkage area.
///
static unsigned getLinkageSize(bool isPPC64, bool isDarwinABI) {
if (isDarwinABI || isPPC64)
return 6 * (isPPC64 ? 8 : 4);
// SVR4 ABI:
return 8;
}
/// getMinCallArgumentsSize - Return the size of the minium PowerPC ABI
/// argument area.
static unsigned getMinCallArgumentsSize(bool isPPC64, bool isDarwinABI) {
// For the Darwin ABI / 64-bit SVR4 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 (isDarwinABI || isPPC64)
return 8 * (isPPC64 ? 8 : 4);
// 32-bit SVR4 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 isPPC64, bool isDarwinABI) {
// The call frame needs to be at least big enough for linkage and 8 args.
return getLinkageSize(isPPC64, isDarwinABI) +
getMinCallArgumentsSize(isPPC64, isDarwinABI);
}
// With the SVR4 ABI, callee-saved registers have fixed offsets on the stack.
const SpillSlot *
getCalleeSavedSpillSlots(unsigned &NumEntries) const {
if (Subtarget.isDarwinABI()) {
NumEntries = 1;
if (Subtarget.isPPC64()) {
static const SpillSlot darwin64Offsets = {PPC::X31, -8};
return &darwin64Offsets;
} else {
static const SpillSlot darwinOffsets = {PPC::R31, -4};
return &darwinOffsets;
}
}
// Early exit if not using the SVR4 ABI.
if (!Subtarget.isSVR4ABI()) {
NumEntries = 0;
return 0;
}
// Note that the offsets here overlap, but this is fixed up in
// processFunctionBeforeFrameFinalized.
static const SpillSlot Offsets[] = {
// Floating-point register save area offsets.
{PPC::F31, -8},
{PPC::F30, -16},
{PPC::F29, -24},
{PPC::F28, -32},
{PPC::F27, -40},
{PPC::F26, -48},
{PPC::F25, -56},
{PPC::F24, -64},
{PPC::F23, -72},
{PPC::F22, -80},
{PPC::F21, -88},
{PPC::F20, -96},
{PPC::F19, -104},
{PPC::F18, -112},
{PPC::F17, -120},
{PPC::F16, -128},
{PPC::F15, -136},
{PPC::F14, -144},
// General register save area offsets.
{PPC::R31, -4},
{PPC::R30, -8},
{PPC::R29, -12},
{PPC::R28, -16},
{PPC::R27, -20},
{PPC::R26, -24},
{PPC::R25, -28},
{PPC::R24, -32},
{PPC::R23, -36},
{PPC::R22, -40},
{PPC::R21, -44},
{PPC::R20, -48},
{PPC::R19, -52},
{PPC::R18, -56},
{PPC::R17, -60},
{PPC::R16, -64},
{PPC::R15, -68},
{PPC::R14, -72},
// CR save area offset. We map each of the nonvolatile CR fields
// to the slot for CR2, which is the first of the nonvolatile CR
// fields to be assigned, so that we only allocate one save slot.
// See PPCRegisterInfo::hasReservedSpillSlot() for more information.
{PPC::CR2, -4},
// VRSAVE save area offset.
{PPC::VRSAVE, -4},
// Vector register save area
{PPC::V31, -16},
{PPC::V30, -32},
{PPC::V29, -48},
{PPC::V28, -64},
{PPC::V27, -80},
{PPC::V26, -96},
{PPC::V25, -112},
{PPC::V24, -128},
{PPC::V23, -144},
{PPC::V22, -160},
{PPC::V21, -176},
{PPC::V20, -192}
};
static const SpillSlot Offsets64[] = {
// Floating-point register save area offsets.
{PPC::F31, -8},
{PPC::F30, -16},
{PPC::F29, -24},
{PPC::F28, -32},
{PPC::F27, -40},
{PPC::F26, -48},
{PPC::F25, -56},
{PPC::F24, -64},
{PPC::F23, -72},
{PPC::F22, -80},
{PPC::F21, -88},
{PPC::F20, -96},
{PPC::F19, -104},
{PPC::F18, -112},
{PPC::F17, -120},
{PPC::F16, -128},
{PPC::F15, -136},
{PPC::F14, -144},
// General register save area offsets.
{PPC::X31, -8},
{PPC::X30, -16},
{PPC::X29, -24},
{PPC::X28, -32},
{PPC::X27, -40},
{PPC::X26, -48},
{PPC::X25, -56},
{PPC::X24, -64},
{PPC::X23, -72},
{PPC::X22, -80},
{PPC::X21, -88},
{PPC::X20, -96},
{PPC::X19, -104},
{PPC::X18, -112},
{PPC::X17, -120},
{PPC::X16, -128},
{PPC::X15, -136},
{PPC::X14, -144},
// VRSAVE save area offset.
{PPC::VRSAVE, -4},
// Vector register save area
{PPC::V31, -16},
{PPC::V30, -32},
{PPC::V29, -48},
{PPC::V28, -64},
{PPC::V27, -80},
{PPC::V26, -96},
{PPC::V25, -112},
{PPC::V24, -128},
{PPC::V23, -144},
{PPC::V22, -160},
{PPC::V21, -176},
{PPC::V20, -192}
};
if (Subtarget.isPPC64()) {
NumEntries = array_lengthof(Offsets64);
return Offsets64;
} else {
NumEntries = array_lengthof(Offsets);
return Offsets;
}
}
};
} // End llvm namespace
#endif