Files
llvm-6502/lib/Target/PowerPC/PPCRegisterInfo.h
Hal Finkel 7ee74a663a Implement builtin_{setjmp/longjmp} on PPC
This implements SJLJ lowering on PPC, making the Clang functions
__builtin_{setjmp/longjmp} functional on PPC platforms. The implementation
strategy is similar to that on X86, with the exception that a branch-and-link
variant is used to get the right jump address. Credit goes to Bill Schmidt for
suggesting the use of the unconditional bcl form (instead of the regular bl
instruction) to limit return-address-cache pollution.

Benchmarking the speed at -O3 of:

static jmp_buf env_sigill;

void foo() {
                __builtin_longjmp(env_sigill,1);
}

main() {
	...

        for (int i = 0; i < c; ++i) {
                if (__builtin_setjmp(env_sigill)) {
                        goto done;
                } else {
                        foo();
                }

done:;
        }

	...
}

vs. the same code using the libc setjmp/longjmp functions on a P7 shows that
this builtin implementation is ~4x faster with Altivec enabled and ~7.25x
faster with Altivec disabled. This comparison is somewhat unfair because the
libc version must also save/restore the VSX registers which we don't yet
support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177666 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-21 21:37:52 +00:00

92 lines
3.1 KiB
C++

//===-- PPCRegisterInfo.h - PowerPC Register Information Impl ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the PowerPC implementation of the TargetRegisterInfo
// class.
//
//===----------------------------------------------------------------------===//
#ifndef POWERPC32_REGISTERINFO_H
#define POWERPC32_REGISTERINFO_H
#include "PPC.h"
#include <map>
#define GET_REGINFO_HEADER
#include "PPCGenRegisterInfo.inc"
namespace llvm {
class PPCSubtarget;
class TargetInstrInfo;
class Type;
class PPCRegisterInfo : public PPCGenRegisterInfo {
std::map<unsigned, unsigned> ImmToIdxMap;
const PPCSubtarget &Subtarget;
const TargetInstrInfo &TII;
public:
PPCRegisterInfo(const PPCSubtarget &SubTarget, const TargetInstrInfo &tii);
/// getPointerRegClass - Return the register class to use to hold pointers.
/// This is used for addressing modes.
virtual const TargetRegisterClass *
getPointerRegClass(const MachineFunction &MF, unsigned Kind=0) const;
unsigned getRegPressureLimit(const TargetRegisterClass *RC,
MachineFunction &MF) const;
/// Code Generation virtual methods...
const uint16_t *getCalleeSavedRegs(const MachineFunction* MF = 0) const;
const uint32_t *getCallPreservedMask(CallingConv::ID CC) const;
const uint32_t *getNoPreservedMask() const;
BitVector getReservedRegs(const MachineFunction &MF) const;
/// We require the register scavenger.
bool requiresRegisterScavenging(const MachineFunction &MF) const {
return true;
}
bool requiresFrameIndexScavenging(const MachineFunction &MF) const {
return true;
}
bool trackLivenessAfterRegAlloc(const MachineFunction &MF) const {
return true;
}
void lowerDynamicAlloc(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS) const;
void lowerCRSpilling(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
void lowerCRRestore(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
void lowerVRSAVESpilling(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
void lowerVRSAVERestore(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
bool hasReservedSpillSlot(const MachineFunction &MF, unsigned Reg,
int &FrameIdx) const;
void eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS = NULL) const;
// Debug information queries.
unsigned getFrameRegister(const MachineFunction &MF) const;
// Exception handling queries.
unsigned getEHExceptionRegister() const;
unsigned getEHHandlerRegister() const;
};
} // end namespace llvm
#endif