//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "pei"
#include "PrologEpilogInserter.h"
+#include "llvm/InlineAsm.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Target/TargetFrameInfo.h"
+#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
#include "llvm/ADT/IndexedMap.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
#include <climits>
char PEI::ID = 0;
-static RegisterPass<PEI>
-X("prologepilog", "Prologue/Epilogue Insertion");
+INITIALIZE_PASS_BEGIN(PEI, "prologepilog",
+ "Prologue/Epilogue Insertion", false, false)
+INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
+INITIALIZE_PASS_END(PEI, "prologepilog",
+ "Prologue/Epilogue Insertion", false, false)
+
+STATISTIC(NumVirtualFrameRegs, "Number of virtual frame regs encountered");
+STATISTIC(NumScavengedRegs, "Number of frame index regs scavenged");
+STATISTIC(NumBytesStackSpace,
+ "Number of bytes used for stack in all functions");
/// createPrologEpilogCodeInserter - This function returns a pass that inserts
/// prolog and epilog code, and eliminates abstract frame references.
bool PEI::runOnMachineFunction(MachineFunction &Fn) {
const Function* F = Fn.getFunction();
const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+
RS = TRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : NULL;
FrameIndexVirtualScavenging = TRI->requiresFrameIndexScavenging(Fn);
- // Get MachineModuleInfo so that we can track the construction of the
- // frame.
- if (MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>())
- Fn.getFrameInfo()->setMachineModuleInfo(MMI);
-
- // Calculate the MaxCallFrameSize and HasCalls variables for the function's
- // frame information. Also eliminates call frame pseudo instructions.
+ // Calculate the MaxCallFrameSize and AdjustsStack variables for the
+ // function's frame information. Also eliminates call frame pseudo
+ // instructions.
calculateCallsInformation(Fn);
// Allow the target machine to make some adjustments to the function
// e.g. UsedPhysRegs before calculateCalleeSavedRegisters.
- TRI->processFunctionBeforeCalleeSavedScan(Fn, RS);
+ TFI->processFunctionBeforeCalleeSavedScan(Fn, RS);
// Scan the function for modified callee saved registers and insert spill code
// for any callee saved registers that are modified.
calculateCalleeSavedRegisters(Fn);
// Determine placement of CSR spill/restore code:
- // - with shrink wrapping, place spills and restores to tightly
+ // - With shrink wrapping, place spills and restores to tightly
// enclose regions in the Machine CFG of the function where
- // they are used. Without shrink wrapping
- // - default (no shrink wrapping), place all spills in the
+ // they are used.
+ // - Without shink wrapping (default), place all spills in the
// entry block, all restores in return blocks.
placeCSRSpillsAndRestores(Fn);
// Allow the target machine to make final modifications to the function
// before the frame layout is finalized.
- TRI->processFunctionBeforeFrameFinalized(Fn);
+ TFI->processFunctionBeforeFrameFinalized(Fn);
// Calculate actual frame offsets for all abstract stack objects...
calculateFrameObjectOffsets(Fn);
// Add prolog and epilog code to the function. This function is required
// to align the stack frame as necessary for any stack variables or
- // called functions. Because of this, calculateCalleeSavedRegisters
- // must be called before this function in order to set the HasCalls
+ // called functions. Because of this, calculateCalleeSavedRegisters()
+ // must be called before this function in order to set the AdjustsStack
// and MaxCallFrameSize variables.
if (!F->hasFnAttr(Attribute::Naked))
insertPrologEpilogCode(Fn);
}
#endif
-/// calculateCallsInformation - Calculate the MaxCallFrameSize and HasCalls
+/// calculateCallsInformation - Calculate the MaxCallFrameSize and AdjustsStack
/// variables for the function's frame information and eliminate call frame
/// pseudo instructions.
void PEI::calculateCallsInformation(MachineFunction &Fn) {
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- MachineFrameInfo *FFI = Fn.getFrameInfo();
+ const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
unsigned MaxCallFrameSize = 0;
- bool HasCalls = FFI->hasCalls();
+ bool AdjustsStack = MFI->adjustsStack();
// Get the function call frame set-up and tear-down instruction opcode
- int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode();
- int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode();
+ int FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ int FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
// Early exit for targets which have no call frame setup/destroy pseudo
// instructions.
" instructions should have a single immediate argument!");
unsigned Size = I->getOperand(0).getImm();
if (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
- HasCalls = true;
+ AdjustsStack = true;
FrameSDOps.push_back(I);
} else if (I->isInlineAsm()) {
- // An InlineAsm might be a call; assume it is to get the stack frame
- // aligned correctly for calls.
- HasCalls = true;
+ // Some inline asm's need a stack frame, as indicated by operand 1.
+ unsigned ExtraInfo = I->getOperand(InlineAsm::MIOp_ExtraInfo).getImm();
+ if (ExtraInfo & InlineAsm::Extra_IsAlignStack)
+ AdjustsStack = true;
}
- FFI->setHasCalls(HasCalls);
- FFI->setMaxCallFrameSize(MaxCallFrameSize);
+ MFI->setAdjustsStack(AdjustsStack);
+ MFI->setMaxCallFrameSize(MaxCallFrameSize);
for (std::vector<MachineBasicBlock::iterator>::iterator
i = FrameSDOps.begin(), e = FrameSDOps.end(); i != e; ++i) {
MachineBasicBlock::iterator I = *i;
// If call frames are not being included as part of the stack frame, and
- // there is no dynamic allocation (therefore referencing frame slots off
- // sp), leave the pseudo ops alone. We'll eliminate them later.
- if (RegInfo->hasReservedCallFrame(Fn) || RegInfo->hasFP(Fn))
+ // the target doesn't indicate otherwise, remove the call frame pseudos
+ // here. The sub/add sp instruction pairs are still inserted, but we don't
+ // need to track the SP adjustment for frame index elimination.
+ if (TFI->canSimplifyCallFramePseudos(Fn))
RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
}
}
/// registers.
void PEI::calculateCalleeSavedRegisters(MachineFunction &Fn) {
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
- MachineFrameInfo *FFI = Fn.getFrameInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
// Get the callee saved register list...
const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(&Fn);
if (CSRegs == 0 || CSRegs[0] == 0)
return;
- // Figure out which *callee saved* registers are modified by the current
- // function, thus needing to be saved and restored in the prolog/epilog.
- const TargetRegisterClass * const *CSRegClasses =
- RegInfo->getCalleeSavedRegClasses(&Fn);
+ // In Naked functions we aren't going to save any registers.
+ if (Fn.getFunction()->hasFnAttr(Attribute::Naked))
+ return;
std::vector<CalleeSavedInfo> CSI;
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
if (Fn.getRegInfo().isPhysRegUsed(Reg)) {
// If the reg is modified, save it!
- CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
+ CSI.push_back(CalleeSavedInfo(Reg));
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) { // Check alias registers too.
if (Fn.getRegInfo().isPhysRegUsed(*AliasSet)) {
- CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
+ CSI.push_back(CalleeSavedInfo(Reg));
break;
}
}
return; // Early exit if no callee saved registers are modified!
unsigned NumFixedSpillSlots;
- const TargetFrameInfo::SpillSlot *FixedSpillSlots =
+ const TargetFrameLowering::SpillSlot *FixedSpillSlots =
TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
// Now that we know which registers need to be saved and restored, allocate
for (std::vector<CalleeSavedInfo>::iterator
I = CSI.begin(), E = CSI.end(); I != E; ++I) {
unsigned Reg = I->getReg();
- const TargetRegisterClass *RC = I->getRegClass();
+ const TargetRegisterClass *RC = RegInfo->getMinimalPhysRegClass(Reg);
int FrameIdx;
if (RegInfo->hasReservedSpillSlot(Fn, Reg, FrameIdx)) {
// Check to see if this physreg must be spilled to a particular stack slot
// on this target.
- const TargetFrameInfo::SpillSlot *FixedSlot = FixedSpillSlots;
+ const TargetFrameLowering::SpillSlot *FixedSlot = FixedSpillSlots;
while (FixedSlot != FixedSpillSlots+NumFixedSpillSlots &&
FixedSlot->Reg != Reg)
++FixedSlot;
// the TargetRegisterClass if the stack alignment is smaller. Use the
// min.
Align = std::min(Align, StackAlign);
- FrameIdx = FFI->CreateStackObject(RC->getSize(), Align, true);
+ FrameIdx = MFI->CreateStackObject(RC->getSize(), Align, true);
if ((unsigned)FrameIdx < MinCSFrameIndex) MinCSFrameIndex = FrameIdx;
if ((unsigned)FrameIdx > MaxCSFrameIndex) MaxCSFrameIndex = FrameIdx;
} else {
// Spill it to the stack where we must.
- FrameIdx = FFI->CreateFixedObject(RC->getSize(), FixedSlot->Offset,
- true, false);
+ FrameIdx = MFI->CreateFixedObject(RC->getSize(), FixedSlot->Offset, true);
}
I->setFrameIdx(FrameIdx);
}
- FFI->setCalleeSavedInfo(CSI);
+ MFI->setCalleeSavedInfo(CSI);
}
/// insertCSRSpillsAndRestores - Insert spill and restore code for
///
void PEI::insertCSRSpillsAndRestores(MachineFunction &Fn) {
// Get callee saved register information.
- MachineFrameInfo *FFI = Fn.getFrameInfo();
- const std::vector<CalleeSavedInfo> &CSI = FFI->getCalleeSavedInfo();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
+ const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
- FFI->setCalleeSavedInfoValid(true);
+ MFI->setCalleeSavedInfoValid(true);
// Early exit if no callee saved registers are modified!
if (CSI.empty())
return;
const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+ const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
MachineBasicBlock::iterator I;
if (! ShrinkWrapThisFunction) {
// Spill using target interface.
I = EntryBlock->begin();
- if (!TII.spillCalleeSavedRegisters(*EntryBlock, I, CSI)) {
+ if (!TFI->spillCalleeSavedRegisters(*EntryBlock, I, CSI, TRI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
// Add the callee-saved register as live-in.
// It's killed at the spill.
EntryBlock->addLiveIn(CSI[i].getReg());
// Insert the spill to the stack frame.
- TII.storeRegToStackSlot(*EntryBlock, I, CSI[i].getReg(), true,
- CSI[i].getFrameIdx(), CSI[i].getRegClass());
+ unsigned Reg = CSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.storeRegToStackSlot(*EntryBlock, I, Reg, true,
+ CSI[i].getFrameIdx(), RC, TRI);
}
}
--BeforeI;
// Restore all registers immediately before the return and any
- // terminators that preceed it.
- if (!TII.restoreCalleeSavedRegisters(*MBB, I, CSI)) {
+ // terminators that precede it.
+ if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- TII.loadRegFromStackSlot(*MBB, I, CSI[i].getReg(),
+ unsigned Reg = CSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.loadRegFromStackSlot(*MBB, I, Reg,
CSI[i].getFrameIdx(),
- CSI[i].getRegClass());
+ RC, TRI);
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
// Insert in reverse order. loadRegFromStackSlot can insert
MBB->addLiveIn(blockCSI[i].getReg());
// Insert the spill to the stack frame.
- TII.storeRegToStackSlot(*MBB, I, blockCSI[i].getReg(),
+ unsigned Reg = blockCSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.storeRegToStackSlot(*MBB, I, Reg,
true,
blockCSI[i].getFrameIdx(),
- blockCSI[i].getRegClass());
+ RC, TRI);
}
}
--BeforeI;
// Restore all registers immediately before the return and any
- // terminators that preceed it.
+ // terminators that precede it.
for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
- TII.loadRegFromStackSlot(*MBB, I, blockCSI[i].getReg(),
+ unsigned Reg = blockCSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.loadRegFromStackSlot(*MBB, I, Reg,
blockCSI[i].getFrameIdx(),
- blockCSI[i].getRegClass());
+ RC, TRI);
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
// Insert in reverse order. loadRegFromStackSlot can insert
/// AdjustStackOffset - Helper function used to adjust the stack frame offset.
static inline void
-AdjustStackOffset(MachineFrameInfo *FFI, int FrameIdx,
+AdjustStackOffset(MachineFrameInfo *MFI, int FrameIdx,
bool StackGrowsDown, int64_t &Offset,
unsigned &MaxAlign) {
// If the stack grows down, add the object size to find the lowest address.
if (StackGrowsDown)
- Offset += FFI->getObjectSize(FrameIdx);
+ Offset += MFI->getObjectSize(FrameIdx);
- unsigned Align = FFI->getObjectAlignment(FrameIdx);
+ unsigned Align = MFI->getObjectAlignment(FrameIdx);
// If the alignment of this object is greater than that of the stack, then
// increase the stack alignment to match.
Offset = (Offset + Align - 1) / Align * Align;
if (StackGrowsDown) {
- FFI->setObjectOffset(FrameIdx, -Offset); // Set the computed offset
+ DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << -Offset << "]\n");
+ MFI->setObjectOffset(FrameIdx, -Offset); // Set the computed offset
} else {
- FFI->setObjectOffset(FrameIdx, Offset);
- Offset += FFI->getObjectSize(FrameIdx);
+ DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << Offset << "]\n");
+ MFI->setObjectOffset(FrameIdx, Offset);
+ Offset += MFI->getObjectSize(FrameIdx);
}
}
/// abstract stack objects.
///
void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
- const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo();
+ const TargetFrameLowering &TFI = *Fn.getTarget().getFrameLowering();
bool StackGrowsDown =
- TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
+ TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
// Loop over all of the stack objects, assigning sequential addresses...
- MachineFrameInfo *FFI = Fn.getFrameInfo();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
// Start at the beginning of the local area.
// The Offset is the distance from the stack top in the direction
// We currently don't support filling in holes in between fixed sized
// objects, so we adjust 'Offset' to point to the end of last fixed sized
// preallocated object.
- for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
+ for (int i = MFI->getObjectIndexBegin(); i != 0; ++i) {
int64_t FixedOff;
if (StackGrowsDown) {
// The maximum distance from the stack pointer is at lower address of
// the object -- which is given by offset. For down growing stack
// the offset is negative, so we negate the offset to get the distance.
- FixedOff = -FFI->getObjectOffset(i);
+ FixedOff = -MFI->getObjectOffset(i);
} else {
// The maximum distance from the start pointer is at the upper
// address of the object.
- FixedOff = FFI->getObjectOffset(i) + FFI->getObjectSize(i);
+ FixedOff = MFI->getObjectOffset(i) + MFI->getObjectSize(i);
}
if (FixedOff > Offset) Offset = FixedOff;
}
// callee saved registers.
if (StackGrowsDown) {
for (unsigned i = MinCSFrameIndex; i <= MaxCSFrameIndex; ++i) {
- // If stack grows down, we need to add size of find the lowest
+ // If the stack grows down, we need to add the size to find the lowest
// address of the object.
- Offset += FFI->getObjectSize(i);
+ Offset += MFI->getObjectSize(i);
- unsigned Align = FFI->getObjectAlignment(i);
+ unsigned Align = MFI->getObjectAlignment(i);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
- FFI->setObjectOffset(i, -Offset); // Set the computed offset
+ MFI->setObjectOffset(i, -Offset); // Set the computed offset
}
} else {
int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex;
for (int i = MaxCSFI; i >= MinCSFI ; --i) {
- unsigned Align = FFI->getObjectAlignment(i);
+ unsigned Align = MFI->getObjectAlignment(i);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
- FFI->setObjectOffset(i, Offset);
- Offset += FFI->getObjectSize(i);
+ MFI->setObjectOffset(i, Offset);
+ Offset += MFI->getObjectSize(i);
}
}
- unsigned MaxAlign = FFI->getMaxAlignment();
+ unsigned MaxAlign = MFI->getMaxAlignment();
// Make sure the special register scavenging spill slot is closest to the
// frame pointer if a frame pointer is required.
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- if (RS && RegInfo->hasFP(Fn) && !RegInfo->needsStackRealignment(Fn)) {
+ if (RS && TFI.hasFP(Fn) && RegInfo->useFPForScavengingIndex(Fn) &&
+ !RegInfo->needsStackRealignment(Fn)) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
- AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
+ AdjustStackOffset(MFI, SFI, StackGrowsDown, Offset, MaxAlign);
+ }
+
+ // FIXME: Once this is working, then enable flag will change to a target
+ // check for whether the frame is large enough to want to use virtual
+ // frame index registers. Functions which don't want/need this optimization
+ // will continue to use the existing code path.
+ if (MFI->getUseLocalStackAllocationBlock()) {
+ unsigned Align = MFI->getLocalFrameMaxAlign();
+
+ // Adjust to alignment boundary.
+ Offset = (Offset + Align - 1) / Align * Align;
+
+ DEBUG(dbgs() << "Local frame base offset: " << Offset << "\n");
+
+ // Resolve offsets for objects in the local block.
+ for (unsigned i = 0, e = MFI->getLocalFrameObjectCount(); i != e; ++i) {
+ std::pair<int, int64_t> Entry = MFI->getLocalFrameObjectMap(i);
+ int64_t FIOffset = (StackGrowsDown ? -Offset : Offset) + Entry.second;
+ DEBUG(dbgs() << "alloc FI(" << Entry.first << ") at SP[" <<
+ FIOffset << "]\n");
+ MFI->setObjectOffset(Entry.first, FIOffset);
+ }
+ // Allocate the local block
+ Offset += MFI->getLocalFrameSize();
+
+ MaxAlign = std::max(Align, MaxAlign);
}
// Make sure that the stack protector comes before the local variables on the
// stack.
- if (FFI->getStackProtectorIndex() >= 0)
- AdjustStackOffset(FFI, FFI->getStackProtectorIndex(), StackGrowsDown,
+ SmallSet<int, 16> LargeStackObjs;
+ if (MFI->getStackProtectorIndex() >= 0) {
+ AdjustStackOffset(MFI, MFI->getStackProtectorIndex(), StackGrowsDown,
Offset, MaxAlign);
+ // Assign large stack objects first.
+ for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
+ if (MFI->isObjectPreAllocated(i) &&
+ MFI->getUseLocalStackAllocationBlock())
+ continue;
+ if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
+ continue;
+ if (RS && (int)i == RS->getScavengingFrameIndex())
+ continue;
+ if (MFI->isDeadObjectIndex(i))
+ continue;
+ if (MFI->getStackProtectorIndex() == (int)i)
+ continue;
+ if (!MFI->MayNeedStackProtector(i))
+ continue;
+
+ AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign);
+ LargeStackObjs.insert(i);
+ }
+ }
+
// Then assign frame offsets to stack objects that are not used to spill
// callee saved registers.
- for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
+ for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
+ if (MFI->isObjectPreAllocated(i) &&
+ MFI->getUseLocalStackAllocationBlock())
+ continue;
if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
continue;
if (RS && (int)i == RS->getScavengingFrameIndex())
continue;
- if (FFI->isDeadObjectIndex(i))
+ if (MFI->isDeadObjectIndex(i))
+ continue;
+ if (MFI->getStackProtectorIndex() == (int)i)
continue;
- if (FFI->getStackProtectorIndex() == (int)i)
+ if (LargeStackObjs.count(i))
continue;
- AdjustStackOffset(FFI, i, StackGrowsDown, Offset, MaxAlign);
+ AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign);
}
// Make sure the special register scavenging spill slot is closest to the
// stack pointer.
- if (RS && (!RegInfo->hasFP(Fn) || RegInfo->needsStackRealignment(Fn))) {
+ if (RS && (!TFI.hasFP(Fn) || RegInfo->needsStackRealignment(Fn) ||
+ !RegInfo->useFPForScavengingIndex(Fn))) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
- AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
+ AdjustStackOffset(MFI, SFI, StackGrowsDown, Offset, MaxAlign);
}
- if (!RegInfo->targetHandlesStackFrameRounding()) {
+ if (!TFI.targetHandlesStackFrameRounding()) {
// If we have reserved argument space for call sites in the function
// immediately on entry to the current function, count it as part of the
// overall stack size.
- if (FFI->hasCalls() && RegInfo->hasReservedCallFrame(Fn))
- Offset += FFI->getMaxCallFrameSize();
+ if (MFI->adjustsStack() && TFI.hasReservedCallFrame(Fn))
+ Offset += MFI->getMaxCallFrameSize();
// Round up the size to a multiple of the alignment. If the function has
// any calls or alloca's, align to the target's StackAlignment value to
// otherwise, for leaf functions, align to the TransientStackAlignment
// value.
unsigned StackAlign;
- if (FFI->hasCalls() || FFI->hasVarSizedObjects() ||
- (RegInfo->needsStackRealignment(Fn) && FFI->getObjectIndexEnd() != 0))
+ if (MFI->adjustsStack() || MFI->hasVarSizedObjects() ||
+ (RegInfo->needsStackRealignment(Fn) && MFI->getObjectIndexEnd() != 0))
StackAlign = TFI.getStackAlignment();
else
StackAlign = TFI.getTransientStackAlignment();
- // If the frame pointer is eliminated, all frame offsets will be relative
- // to SP not FP; align to MaxAlign so this works.
+
+ // If the frame pointer is eliminated, all frame offsets will be relative to
+ // SP not FP. Align to MaxAlign so this works.
StackAlign = std::max(StackAlign, MaxAlign);
unsigned AlignMask = StackAlign - 1;
Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
}
// Update frame info to pretend that this is part of the stack...
- FFI->setStackSize(Offset - LocalAreaOffset);
+ int64_t StackSize = Offset - LocalAreaOffset;
+ MFI->setStackSize(StackSize);
+ NumBytesStackSpace += StackSize;
}
-
/// insertPrologEpilogCode - Scan the function for modified callee saved
/// registers, insert spill code for these callee saved registers, then add
/// prolog and epilog code to the function.
///
void PEI::insertPrologEpilogCode(MachineFunction &Fn) {
- const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
+ const TargetFrameLowering &TFI = *Fn.getTarget().getFrameLowering();
// Add prologue to the function...
- TRI->emitPrologue(Fn);
+ TFI.emitPrologue(Fn);
// Add epilogue to restore the callee-save registers in each exiting block
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
// If last instruction is a return instruction, add an epilogue
if (!I->empty() && I->back().getDesc().isReturn())
- TRI->emitEpilogue(Fn, *I);
+ TFI.emitEpilogue(Fn, *I);
}
-}
+ // Emit additional code that is required to support segmented stacks, if
+ // we've been asked for it. This, when linked with a runtime with support
+ // for segmented stacks (libgcc is one), will result in allocating stack
+ // space in small chunks instead of one large contiguous block.
+ if (EnableSegmentedStacks)
+ TFI.adjustForSegmentedStacks(Fn);
+}
/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical
/// register references and actual offsets.
const TargetMachine &TM = Fn.getTarget();
assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!");
+ const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
- const TargetFrameInfo *TFI = TM.getFrameInfo();
+ const TargetFrameLowering *TFI = TM.getFrameLowering();
bool StackGrowsDown =
- TFI->getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
- int FrameSetupOpcode = TRI.getCallFrameSetupOpcode();
- int FrameDestroyOpcode = TRI.getCallFrameDestroyOpcode();
+ TFI->getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
+ int FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ int FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
for (MachineFunction::iterator BB = Fn.begin(),
E = Fn.end(); BB != E; ++BB) {
+#ifndef NDEBUG
+ int SPAdjCount = 0; // frame setup / destroy count.
+#endif
int SPAdj = 0; // SP offset due to call frame setup / destroy.
if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(BB);
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
+#ifndef NDEBUG
+ // Track whether we see even pairs of them
+ SPAdjCount += I->getOpcode() == FrameSetupOpcode ? 1 : -1;
+#endif
// Remember how much SP has been adjusted to create the call
// frame.
int Size = I->getOperand(0).getImm();
// If this instruction has a FrameIndex operand, we need to
// use that target machine register info object to eliminate
// it.
- int Value;
- unsigned VReg =
- TRI.eliminateFrameIndex(MI, SPAdj, &Value,
- FrameIndexVirtualScavenging ? NULL : RS);
- if (VReg) {
- assert (FrameIndexVirtualScavenging &&
- "Not scavenging, but virtual returned from "
- "eliminateFrameIndex()!");
- FrameConstantRegMap[VReg] = FrameConstantEntry(Value, SPAdj);
- }
+ TRI.eliminateFrameIndex(MI, SPAdj,
+ FrameIndexVirtualScavenging ? NULL : RS);
// Reset the iterator if we were at the beginning of the BB.
if (AtBeginning) {
if (RS && !FrameIndexVirtualScavenging && MI) RS->forward(MI);
}
- assert(SPAdj == 0 && "Unbalanced call frame setup / destroy pairs?");
+ // If we have evenly matched pairs of frame setup / destroy instructions,
+ // make sure the adjustments come out to zero. If we don't have matched
+ // pairs, we can't be sure the missing bit isn't in another basic block
+ // due to a custom inserter playing tricks, so just asserting SPAdj==0
+ // isn't sufficient. See tMOVCC on Thumb1, for example.
+ assert((SPAdjCount || SPAdj == 0) &&
+ "Unbalanced call frame setup / destroy pairs?");
}
}
-/// findLastUseReg - find the killing use of the specified register within
-/// the instruciton range. Return the operand number of the kill in Operand.
-static MachineBasicBlock::iterator
-findLastUseReg(MachineBasicBlock::iterator I, MachineBasicBlock::iterator ME,
- unsigned Reg) {
- // Scan forward to find the last use of this virtual register
- for (++I; I != ME; ++I) {
- MachineInstr *MI = I;
- bool isDefInsn = false;
- bool isKillInsn = false;
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
- if (MI->getOperand(i).isReg()) {
- unsigned OpReg = MI->getOperand(i).getReg();
- if (OpReg == 0 || !TargetRegisterInfo::isVirtualRegister(OpReg))
- continue;
- assert (OpReg == Reg
- && "overlapping use of scavenged index register!");
- // If this is the killing use, we have a candidate.
- if (MI->getOperand(i).isKill())
- isKillInsn = true;
- else if (MI->getOperand(i).isDef())
- isDefInsn = true;
- }
- if (isKillInsn && !isDefInsn)
- return I;
- }
- // If we hit the end of the basic block, there was no kill of
- // the virtual register, which is wrong.
- assert (0 && "scavenged index register never killed!");
- return ME;
-}
-
/// scavengeFrameVirtualRegs - Replace all frame index virtual registers
/// with physical registers. Use the register scavenger to find an
/// appropriate register to use.
E = Fn.end(); BB != E; ++BB) {
RS->enterBasicBlock(BB);
- // FIXME: The logic flow in this function is still too convoluted.
- // It needs a cleanup refactoring. Do that in preparation for tracking
- // more than one scratch register value and using ranges to find
- // available scratch registers.
- unsigned CurrentVirtReg = 0;
- unsigned CurrentScratchReg = 0;
- bool havePrevValue = false;
- int PrevValue = 0;
- MachineInstr *PrevLastUseMI = NULL;
- unsigned PrevLastUseOp = 0;
- bool trackingCurrentValue = false;
+ unsigned VirtReg = 0;
+ unsigned ScratchReg = 0;
int SPAdj = 0;
- int Value = 0;
// The instruction stream may change in the loop, so check BB->end()
// directly.
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
MachineInstr *MI = I;
- bool isDefInsn = false;
- bool isKillInsn = false;
- bool clobbersScratchReg = false;
- bool DoIncr = true;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
if (MI->getOperand(i).isReg()) {
MachineOperand &MO = MI->getOperand(i);
unsigned Reg = MO.getReg();
if (Reg == 0)
continue;
- if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
- // If we have a previous scratch reg, check and see if anything
- // here kills whatever value is in there.
- if (Reg == CurrentScratchReg) {
- if (MO.isUse()) {
- // Two-address operands implicitly kill
- if (MO.isKill() || MI->isRegTiedToDefOperand(i))
- clobbersScratchReg = true;
- } else {
- assert (MO.isDef());
- clobbersScratchReg = true;
- }
- }
+ if (!TargetRegisterInfo::isVirtualRegister(Reg))
continue;
- }
- // If this is a def, remember that this insn defines the value.
- // This lets us properly consider insns which re-use the scratch
- // register, such as r2 = sub r2, #imm, in the middle of the
- // scratch range.
- if (MO.isDef())
- isDefInsn = true;
+
+ ++NumVirtualFrameRegs;
// Have we already allocated a scratch register for this virtual?
- if (Reg != CurrentVirtReg) {
+ if (Reg != VirtReg) {
// When we first encounter a new virtual register, it
// must be a definition.
assert(MI->getOperand(i).isDef() &&
"frame index virtual missing def!");
- // We can't have nested virtual register live ranges because
- // there's only a guarantee of one scavenged register at a time.
- assert (CurrentVirtReg == 0 &&
- "overlapping frame index virtual registers!");
-
- // If the target gave us information about what's in the register,
- // we can use that to re-use scratch regs.
- DenseMap<unsigned, FrameConstantEntry>::iterator Entry =
- FrameConstantRegMap.find(Reg);
- trackingCurrentValue = Entry != FrameConstantRegMap.end();
- if (trackingCurrentValue) {
- SPAdj = (*Entry).second.second;
- Value = (*Entry).second.first;
- } else
- SPAdj = Value = 0;
-
- // If the scratch register from the last allocation is still
- // available, see if the value matches. If it does, just re-use it.
- if (trackingCurrentValue && havePrevValue && PrevValue == Value) {
- // FIXME: This assumes that the instructions in the live range
- // for the virtual register are exclusively for the purpose
- // of populating the value in the register. That's reasonable
- // for these frame index registers, but it's still a very, very
- // strong assumption. rdar://7322732. Better would be to
- // explicitly check each instruction in the range for references
- // to the virtual register. Only delete those insns that
- // touch the virtual register.
-
- // Find the last use of the new virtual register. Remove all
- // instruction between here and there, and update the current
- // instruction to reference the last use insn instead.
- MachineBasicBlock::iterator LastUseMI =
- findLastUseReg(I, BB->end(), Reg);
-
- // Remove all instructions up 'til the last use, since they're
- // just calculating the value we already have.
- BB->erase(I, LastUseMI);
- I = LastUseMI;
-
- // Extend the live range of the scratch register
- PrevLastUseMI->getOperand(PrevLastUseOp).setIsKill(false);
- RS->setUsed(CurrentScratchReg);
- CurrentVirtReg = Reg;
-
- // We deleted the instruction we were scanning the operands of.
- // Jump back to the instruction iterator loop. Don't increment
- // past this instruction since we updated the iterator already.
- DoIncr = false;
- break;
- }
-
// Scavenge a new scratch register
- CurrentVirtReg = Reg;
+ VirtReg = Reg;
const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(Reg);
- CurrentScratchReg = RS->FindUnusedReg(RC);
- if (CurrentScratchReg == 0)
- // No register is "free". Scavenge a register.
- CurrentScratchReg = RS->scavengeRegister(RC, I, SPAdj);
-
- PrevValue = Value;
+ ScratchReg = RS->scavengeRegister(RC, I, SPAdj);
+ ++NumScavengedRegs;
}
- // replace this reference to the virtual register with the
+ // Replace this reference to the virtual register with the
// scratch register.
- assert (CurrentScratchReg && "Missing scratch register!");
- MI->getOperand(i).setReg(CurrentScratchReg);
+ assert (ScratchReg && "Missing scratch register!");
+ MI->getOperand(i).setReg(ScratchReg);
- if (MI->getOperand(i).isKill()) {
- isKillInsn = true;
- PrevLastUseOp = i;
- PrevLastUseMI = MI;
- }
}
}
- // If this is the last use of the scratch, stop tracking it. The
- // last use will be a kill operand in an instruction that does
- // not also define the scratch register.
- if (isKillInsn && !isDefInsn) {
- CurrentVirtReg = 0;
- havePrevValue = trackingCurrentValue;
- }
- // Similarly, notice if instruction clobbered the value in the
- // register we're tracking for possible later reuse. This is noted
- // above, but enforced here since the value is still live while we
- // process the rest of the operands of the instruction.
- if (clobbersScratchReg) {
- havePrevValue = false;
- CurrentScratchReg = 0;
- }
- if (DoIncr) {
- RS->forward(I);
- ++I;
- }
+ RS->forward(I);
+ ++I;
}
}
}
projects / oota-llvm.git / blobdiff