[SystemZ] Fix caller-allocated save slot FIXME

Get rid of some old code (and associated FIXME) for handling the
caller-allocated register save area.  No behavioural change intended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185525 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Richard Sandiford 2013-07-03 09:11:00 +00:00
parent 52f5a65f84
commit 52c28b07f0
3 changed files with 21 additions and 46 deletions

View File

@ -18,15 +18,10 @@
using namespace llvm;
SystemZFrameLowering::SystemZFrameLowering(const SystemZTargetMachine &tm,
const SystemZSubtarget &sti)
: TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 8,
-SystemZMC::CallFrameSize),
TM(tm),
STI(sti) {
namespace {
// The ABI-defined register save slots, relative to the incoming stack
// pointer.
static const unsigned SpillOffsetTable[][2] = {
static const TargetFrameLowering::SpillSlot SpillOffsetTable[] = {
{ SystemZ::R2D, 0x10 },
{ SystemZ::R3D, 0x18 },
{ SystemZ::R4D, 0x20 },
@ -46,11 +41,23 @@ SystemZFrameLowering::SystemZFrameLowering(const SystemZTargetMachine &tm,
{ SystemZ::F4D, 0x90 },
{ SystemZ::F6D, 0x98 }
};
}
SystemZFrameLowering::SystemZFrameLowering(const SystemZTargetMachine &tm,
const SystemZSubtarget &sti)
: TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 8,
-SystemZMC::CallFrameSize, 8),
TM(tm), STI(sti) {
// Create a mapping from register number to save slot offset.
RegSpillOffsets.grow(SystemZ::NUM_TARGET_REGS);
for (unsigned I = 0, E = array_lengthof(SpillOffsetTable); I != E; ++I)
RegSpillOffsets[SpillOffsetTable[I][0]] = SpillOffsetTable[I][1];
RegSpillOffsets[SpillOffsetTable[I].Reg] = SpillOffsetTable[I].Offset;
}
const TargetFrameLowering::SpillSlot *
SystemZFrameLowering::getCalleeSavedSpillSlots(unsigned &NumEntries) const {
NumEntries = array_lengthof(SpillOffsetTable);
return SpillOffsetTable;
}
void SystemZFrameLowering::
@ -127,14 +134,12 @@ spillCalleeSavedRegisters(MachineBasicBlock &MBB,
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Scan the call-saved GPRs and find the bounds of the register spill area.
unsigned SavedGPRFrameSize = 0;
unsigned LowGPR = 0;
unsigned HighGPR = SystemZ::R15D;
unsigned StartOffset = -1U;
for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
unsigned Reg = CSI[I].getReg();
if (SystemZ::GR64BitRegClass.contains(Reg)) {
SavedGPRFrameSize += 8;
unsigned Offset = RegSpillOffsets[Reg];
assert(Offset && "Unexpected GPR save");
if (StartOffset > Offset) {
@ -144,9 +149,7 @@ spillCalleeSavedRegisters(MachineBasicBlock &MBB,
}
}
// Save information about the range and location of the call-saved
// registers, for use by the epilogue inserter.
ZFI->setSavedGPRFrameSize(SavedGPRFrameSize);
// Save the range of call-saved registers, for use by the epilogue inserter.
ZFI->setLowSavedGPR(LowGPR);
ZFI->setHighSavedGPR(HighGPR);
@ -449,11 +452,6 @@ int SystemZFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
// offset is therefore negative.
int64_t Offset = (MFFrame->getObjectOffset(FI) +
MFFrame->getOffsetAdjustment());
if (FI >= 0)
// Non-fixed objects are allocated below the incoming stack pointer.
// Account for the space at the top of the frame that we choose not
// to allocate.
Offset += getUnallocatedTopBytes(MF);
// Make the offset relative to the incoming stack pointer.
Offset -= getOffsetOfLocalArea();
@ -464,11 +462,6 @@ int SystemZFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
return Offset;
}
uint64_t SystemZFrameLowering::
getUnallocatedTopBytes(const MachineFunction &MF) const {
return MF.getInfo<SystemZMachineFunctionInfo>()->getSavedGPRFrameSize();
}
uint64_t SystemZFrameLowering::
getAllocatedStackSize(const MachineFunction &MF) const {
const MachineFrameInfo *MFFrame = MF.getFrameInfo();
@ -476,9 +469,6 @@ getAllocatedStackSize(const MachineFunction &MF) const {
// Start with the size of the local variables and spill slots.
uint64_t StackSize = MFFrame->getStackSize();
// Remove any bytes that we choose not to allocate.
StackSize -= getUnallocatedTopBytes(MF);
// Include space for an emergency spill slot, if one might be needed.
StackSize += getEmergencySpillSlotSize(MF);

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@ -29,7 +29,9 @@ public:
SystemZFrameLowering(const SystemZTargetMachine &tm,
const SystemZSubtarget &sti);
// Override FrameLowering.
// Override TargetFrameLowering.
virtual const SpillSlot *getCalleeSavedSpillSlots(unsigned &NumEntries) const
LLVM_OVERRIDE;
virtual void
processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const LLVM_OVERRIDE;
@ -59,16 +61,6 @@ public:
MachineBasicBlock::iterator MI) const
LLVM_OVERRIDE;
// The target-independent code automatically allocates save slots for
// call-saved GPRs. However, we don't need those slots for SystemZ,
// because the ABI sets aside GPR save slots in the caller-allocated part
// of the frame. Since the target-independent code puts this unneeded
// area at the top of the callee-allocated part of frame, we choose not
// to allocate it and adjust the offsets accordingly. Return the
// size of this unallocated area.
// FIXME: seems a bit hackish.
uint64_t getUnallocatedTopBytes(const MachineFunction &MF) const;
// Return the number of bytes in the callee-allocated part of the frame.
uint64_t getAllocatedStackSize(const MachineFunction &MF) const;

View File

@ -15,7 +15,6 @@
namespace llvm {
class SystemZMachineFunctionInfo : public MachineFunctionInfo {
unsigned SavedGPRFrameSize;
unsigned LowSavedGPR;
unsigned HighSavedGPR;
unsigned VarArgsFirstGPR;
@ -26,14 +25,8 @@ class SystemZMachineFunctionInfo : public MachineFunctionInfo {
public:
explicit SystemZMachineFunctionInfo(MachineFunction &MF)
: SavedGPRFrameSize(0), LowSavedGPR(0), HighSavedGPR(0), VarArgsFirstGPR(0),
VarArgsFirstFPR(0), VarArgsFrameIndex(0), RegSaveFrameIndex(0),
ManipulatesSP(false) {}
// Get and set the number of bytes allocated by generic code to store
// call-saved GPRs.
unsigned getSavedGPRFrameSize() const { return SavedGPRFrameSize; }
void setSavedGPRFrameSize(unsigned bytes) { SavedGPRFrameSize = bytes; }
: LowSavedGPR(0), HighSavedGPR(0), VarArgsFirstGPR(0), VarArgsFirstFPR(0),
VarArgsFrameIndex(0), RegSaveFrameIndex(0), ManipulatesSP(false) {}
// Get and set the first call-saved GPR that should be saved and restored
// by this function. This is 0 if no GPRs need to be saved or restored.