// This pass must be run after register allocation. After this pass is
// executed, it is illegal to construct MO_FrameIndex operands.
//
+// This pass provides an optional shrink wrapping variant of prolog/epilog
+// insertion, enabled via --shrink-wrap. See ShrinkWrapping.cpp.
+//
//===----------------------------------------------------------------------===//
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "PrologEpilogInserter.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/MRegisterInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/STLExtras.h"
#include <climits>
-using namespace llvm;
-namespace {
- struct VISIBILITY_HIDDEN PEI : public MachineFunctionPass {
- static char ID;
- PEI() : MachineFunctionPass((intptr_t)&ID) {}
+using namespace llvm;
- const char *getPassName() const {
- return "Prolog/Epilog Insertion & Frame Finalization";
- }
-
- /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
- /// frame indexes with appropriate references.
- ///
- bool runOnMachineFunction(MachineFunction &Fn) {
- const MRegisterInfo *MRI = Fn.getTarget().getRegisterInfo();
- RS = MRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : NULL;
-
- // Get MachineModuleInfo so that we can track the construction of the
- // frame.
- if (MachineModuleInfo *MMI = getAnalysisToUpdate<MachineModuleInfo>())
- Fn.getFrameInfo()->setMachineModuleInfo(MMI);
-
- // Allow the target machine to make some adjustments to the function
- // e.g. UsedPhysRegs before calculateCalleeSavedRegisters.
- MRI->processFunctionBeforeCalleeSavedScan(Fn, RS);
-
- // Scan the function for modified callee saved registers and insert spill
- // code for any callee saved registers that are modified. Also calculate
- // the MaxCallFrameSize and HasCalls variables for the function's frame
- // information and eliminates call frame pseudo instructions.
- calculateCalleeSavedRegisters(Fn);
-
- // Add the code to save and restore the callee saved registers
- saveCalleeSavedRegisters(Fn);
-
- // Allow the target machine to make final modifications to the function
- // before the frame layout is finalized.
- Fn.getTarget().getRegisterInfo()->processFunctionBeforeFrameFinalized(Fn);
-
- // Calculate actual frame offsets for all of the 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
- // and MaxCallFrameSize variables.
- insertPrologEpilogCode(Fn);
-
- // Replace all MO_FrameIndex operands with physical register references
- // and actual offsets.
- //
- replaceFrameIndices(Fn);
-
- delete RS;
- return true;
- }
-
- private:
- RegScavenger *RS;
-
- // MinCSFrameIndex, MaxCSFrameIndex - Keeps the range of callee saved
- // stack frame indexes.
- unsigned MinCSFrameIndex, MaxCSFrameIndex;
-
- void calculateCalleeSavedRegisters(MachineFunction &Fn);
- void saveCalleeSavedRegisters(MachineFunction &Fn);
- void calculateFrameObjectOffsets(MachineFunction &Fn);
- void replaceFrameIndices(MachineFunction &Fn);
- void insertPrologEpilogCode(MachineFunction &Fn);
- };
- char PEI::ID = 0;
-}
+char PEI::ID = 0;
+static RegisterPass<PEI>
+X("prologepilog", "Prologue/Epilogue Insertion");
/// createPrologEpilogCodeInserter - This function returns a pass that inserts
/// prolog and epilog code, and eliminates abstract frame references.
///
FunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); }
-
-/// calculateCalleeSavedRegisters - Scan the function for modified callee saved
-/// registers. Also calculate the MaxCallFrameSize and HasCalls variables for
-/// the function's frame information and eliminates call frame pseudo
-/// instructions.
+/// runOnMachineFunction - Insert prolog/epilog code and replace abstract
+/// frame indexes with appropriate references.
///
-void PEI::calculateCalleeSavedRegisters(MachineFunction &Fn) {
- const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
+bool PEI::runOnMachineFunction(MachineFunction &Fn) {
+ const Function* F = Fn.getFunction();
+ const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
+ 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.
+ calculateCallsInformation(Fn);
+
+ // Allow the target machine to make some adjustments to the function
+ // e.g. UsedPhysRegs before calculateCalleeSavedRegisters.
+ TRI->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
+ // 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
+ // entry block, all restores in return blocks.
+ placeCSRSpillsAndRestores(Fn);
+
+ // Add the code to save and restore the callee saved registers
+ if (!F->hasFnAttr(Attribute::Naked))
+ insertCSRSpillsAndRestores(Fn);
+
+ // Allow the target machine to make final modifications to the function
+ // before the frame layout is finalized.
+ TRI->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
+ // and MaxCallFrameSize variables.
+ if (!F->hasFnAttr(Attribute::Naked))
+ insertPrologEpilogCode(Fn);
+
+ // Replace all MO_FrameIndex operands with physical register references
+ // and actual offsets.
+ //
+ replaceFrameIndices(Fn);
- // Get the callee saved register list...
- const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(&Fn);
+ // If register scavenging is needed, as we've enabled doing it as a
+ // post-pass, scavenge the virtual registers that frame index elimiation
+ // inserted.
+ if (TRI->requiresRegisterScavenging(Fn) && FrameIndexVirtualScavenging)
+ scavengeFrameVirtualRegs(Fn);
- // Get the function call frame set-up and tear-down instruction opcode
- int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode();
- int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode();
+ delete RS;
+ clearAllSets();
+ return true;
+}
- // These are used to keep track the callee-save area. Initialize them.
- MinCSFrameIndex = INT_MAX;
- MaxCSFrameIndex = 0;
+#if 0
+void PEI::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ if (ShrinkWrapping || ShrinkWrapFunc != "") {
+ AU.addRequired<MachineLoopInfo>();
+ AU.addRequired<MachineDominatorTree>();
+ }
+ AU.addPreserved<MachineLoopInfo>();
+ AU.addPreserved<MachineDominatorTree>();
+ MachineFunctionPass::getAnalysisUsage(AU);
+}
+#endif
- // Early exit for targets which have no callee saved registers and no call
- // frame setup/destroy pseudo instructions.
- if ((CSRegs == 0 || CSRegs[0] == 0) &&
- FrameSetupOpcode == -1 && FrameDestroyOpcode == -1)
- return;
+/// calculateCallsInformation - Calculate the MaxCallFrameSize and HasCalls
+/// variables for the function's frame information and eliminate call frame
+/// pseudo instructions.
+void PEI::calculateCallsInformation(MachineFunction &Fn) {
+ const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
unsigned MaxCallFrameSize = 0;
bool HasCalls = false;
+ // Get the function call frame set-up and tear-down instruction opcode
+ int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode();
+ int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode();
+
+ // Early exit for targets which have no call frame setup/destroy pseudo
+ // instructions.
+ if (FrameSetupOpcode == -1 && FrameDestroyOpcode == -1)
+ return;
+
std::vector<MachineBasicBlock::iterator> FrameSDOps;
for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB)
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I)
if (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
HasCalls = true;
FrameSDOps.push_back(I);
+ } else if (I->getOpcode() == TargetInstrInfo::INLINEASM) {
+ // An InlineAsm might be a call; assume it is to get the stack frame
+ // aligned correctly for calls.
+ HasCalls = true;
}
MachineFrameInfo *FFI = Fn.getFrameInfo();
FFI->setHasCalls(HasCalls);
FFI->setMaxCallFrameSize(MaxCallFrameSize);
- for (unsigned i = 0, e = FrameSDOps.size(); i != e; ++i) {
- MachineBasicBlock::iterator I = FrameSDOps[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.
+ 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))
RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
}
+}
+
+
+/// calculateCalleeSavedRegisters - Scan the function for modified callee saved
+/// registers.
+void PEI::calculateCalleeSavedRegisters(MachineFunction &Fn) {
+ const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
+ const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
+ MachineFrameInfo *FFI = Fn.getFrameInfo();
+
+ // Get the callee saved register list...
+ const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(&Fn);
- // Now figure out which *callee saved* registers are modified by the current
+ // These are used to keep track the callee-save area. Initialize them.
+ MinCSFrameIndex = INT_MAX;
+ MaxCSFrameIndex = 0;
+
+ // Early exit for targets which have no callee saved registers.
+ 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 =
+ const TargetRegisterClass * const *CSRegClasses =
RegInfo->getCalleeSavedRegClasses(&Fn);
+
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!
+ // If the reg is modified, save it!
CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
return; // Early exit if no callee saved registers are modified!
unsigned NumFixedSpillSlots;
- const std::pair<unsigned,int> *FixedSpillSlots =
+ const TargetFrameInfo::SpillSlot *FixedSpillSlots =
TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
// Now that we know which registers need to be saved and restored, allocate
// stack slots for them.
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- unsigned Reg = CSI[i].getReg();
- const TargetRegisterClass *RC = CSI[i].getRegClass();
+ for (std::vector<CalleeSavedInfo>::iterator
+ I = CSI.begin(), E = CSI.end(); I != E; ++I) {
+ unsigned Reg = I->getReg();
+ const TargetRegisterClass *RC = I->getRegClass();
+
+ int FrameIdx;
+ if (RegInfo->hasReservedSpillSlot(Fn, Reg, FrameIdx)) {
+ I->setFrameIdx(FrameIdx);
+ continue;
+ }
// Check to see if this physreg must be spilled to a particular stack slot
// on this target.
- const std::pair<unsigned,int> *FixedSlot = FixedSpillSlots;
+ const TargetFrameInfo::SpillSlot *FixedSlot = FixedSpillSlots;
while (FixedSlot != FixedSpillSlots+NumFixedSpillSlots &&
- FixedSlot->first != Reg)
+ FixedSlot->Reg != Reg)
++FixedSlot;
- int FrameIdx;
- if (FixedSlot == FixedSpillSlots+NumFixedSpillSlots) {
+ if (FixedSlot == FixedSpillSlots + NumFixedSpillSlots) {
// Nope, just spill it anywhere convenient.
unsigned Align = RC->getAlignment();
unsigned StackAlign = TFI->getStackAlignment();
- // We may not be able to sastify the desired alignment specification of
- // the TargetRegisterClass if the stack alignment is smaller. Use the min.
+
+ // We may not be able to satisfy the desired alignment specification of
+ // the TargetRegisterClass if the stack alignment is smaller. Use the
+ // min.
Align = std::min(Align, StackAlign);
- FrameIdx = FFI->CreateStackObject(RC->getSize(), Align);
+ FrameIdx = FFI->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->second);
+ FrameIdx = FFI->CreateFixedObject(RC->getSize(), FixedSlot->Offset);
}
- CSI[i].setFrameIdx(FrameIdx);
+
+ I->setFrameIdx(FrameIdx);
}
FFI->setCalleeSavedInfo(CSI);
}
-/// saveCalleeSavedRegisters - Insert spill code for any callee saved registers
-/// that are modified in the function.
+/// insertCSRSpillsAndRestores - Insert spill and restore code for
+/// callee saved registers used in the function, handling shrink wrapping.
///
-void PEI::saveCalleeSavedRegisters(MachineFunction &Fn) {
+void PEI::insertCSRSpillsAndRestores(MachineFunction &Fn) {
// Get callee saved register information.
MachineFrameInfo *FFI = Fn.getFrameInfo();
const std::vector<CalleeSavedInfo> &CSI = FFI->getCalleeSavedInfo();
-
+
+ FFI->setCalleeSavedInfoValid(true);
+
// Early exit if no callee saved registers are modified!
if (CSI.empty())
return;
- const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
-
- // Now that we have a stack slot for each register to be saved, insert spill
- // code into the entry block.
- MachineBasicBlock *MBB = Fn.begin();
- MachineBasicBlock::iterator I = MBB->begin();
- if (!TII.spillCalleeSavedRegisters(*MBB, I, CSI)) {
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- // Add the callee-saved register as live-in. It's killed at the spill.
- MBB->addLiveIn(CSI[i].getReg());
-
- // Insert the spill to the stack frame.
- TII.storeRegToStackSlot(*MBB, I, CSI[i].getReg(), true,
- CSI[i].getFrameIdx(), CSI[i].getRegClass());
+ MachineBasicBlock::iterator I;
+
+ if (! ShrinkWrapThisFunction) {
+ // Spill using target interface.
+ I = EntryBlock->begin();
+ if (!TII.spillCalleeSavedRegisters(*EntryBlock, I, CSI)) {
+ 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());
+ }
}
- }
- // Add code to restore the callee-save registers in each exiting block.
- for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI)
- // If last instruction is a return instruction, add an epilogue.
- if (!FI->empty() && TII.isReturn(FI->back().getOpcode())) {
- MBB = FI;
+ // Restore using target interface.
+ for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri) {
+ MachineBasicBlock* MBB = ReturnBlocks[ri];
I = MBB->end(); --I;
// Skip over all terminator instructions, which are part of the return
// sequence.
MachineBasicBlock::iterator I2 = I;
- while (I2 != MBB->begin() && TII.isTerminatorInstr((--I2)->getOpcode()))
+ while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator())
I = I2;
bool AtStart = I == MBB->begin();
MachineBasicBlock::iterator BeforeI = I;
if (!AtStart)
--BeforeI;
-
- // Restore all registers immediately before the return and any terminators
- // that preceed it.
+
+ // Restore all registers immediately before the return and any
+ // terminators that preceed it.
if (!TII.restoreCalleeSavedRegisters(*MBB, I, CSI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
TII.loadRegFromStackSlot(*MBB, I, CSI[i].getReg(),
- CSI[i].getFrameIdx(),
- CSI[i].getRegClass());
+ CSI[i].getFrameIdx(),
+ CSI[i].getRegClass());
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
- // Insert in reverse order. loadRegFromStackSlot can insert multiple
- // instructions.
+ // Insert in reverse order. loadRegFromStackSlot can insert
+ // multiple instructions.
if (AtStart)
I = MBB->begin();
else {
}
}
}
+ return;
+ }
+
+ // Insert spills.
+ std::vector<CalleeSavedInfo> blockCSI;
+ for (CSRegBlockMap::iterator BI = CSRSave.begin(),
+ BE = CSRSave.end(); BI != BE; ++BI) {
+ MachineBasicBlock* MBB = BI->first;
+ CSRegSet save = BI->second;
+
+ if (save.empty())
+ continue;
+
+ blockCSI.clear();
+ for (CSRegSet::iterator RI = save.begin(),
+ RE = save.end(); RI != RE; ++RI) {
+ blockCSI.push_back(CSI[*RI]);
+ }
+ assert(blockCSI.size() > 0 &&
+ "Could not collect callee saved register info");
+
+ I = MBB->begin();
+
+ // When shrink wrapping, use stack slot stores/loads.
+ for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
+ // Add the callee-saved register as live-in.
+ // It's killed at the spill.
+ MBB->addLiveIn(blockCSI[i].getReg());
+
+ // Insert the spill to the stack frame.
+ TII.storeRegToStackSlot(*MBB, I, blockCSI[i].getReg(),
+ true,
+ blockCSI[i].getFrameIdx(),
+ blockCSI[i].getRegClass());
+ }
+ }
+
+ for (CSRegBlockMap::iterator BI = CSRRestore.begin(),
+ BE = CSRRestore.end(); BI != BE; ++BI) {
+ MachineBasicBlock* MBB = BI->first;
+ CSRegSet restore = BI->second;
+
+ if (restore.empty())
+ continue;
+
+ blockCSI.clear();
+ for (CSRegSet::iterator RI = restore.begin(),
+ RE = restore.end(); RI != RE; ++RI) {
+ blockCSI.push_back(CSI[*RI]);
+ }
+ assert(blockCSI.size() > 0 &&
+ "Could not find callee saved register info");
+
+ // If MBB is empty and needs restores, insert at the _beginning_.
+ if (MBB->empty()) {
+ I = MBB->begin();
+ } else {
+ I = MBB->end();
+ --I;
+
+ // Skip over all terminator instructions, which are part of the
+ // return sequence.
+ if (! I->getDesc().isTerminator()) {
+ ++I;
+ } else {
+ MachineBasicBlock::iterator I2 = I;
+ while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator())
+ I = I2;
+ }
+ }
+
+ bool AtStart = I == MBB->begin();
+ MachineBasicBlock::iterator BeforeI = I;
+ if (!AtStart)
+ --BeforeI;
+
+ // Restore all registers immediately before the return and any
+ // terminators that preceed it.
+ for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
+ TII.loadRegFromStackSlot(*MBB, I, blockCSI[i].getReg(),
+ blockCSI[i].getFrameIdx(),
+ blockCSI[i].getRegClass());
+ assert(I != MBB->begin() &&
+ "loadRegFromStackSlot didn't insert any code!");
+ // Insert in reverse order. loadRegFromStackSlot can insert
+ // multiple instructions.
+ if (AtStart)
+ I = MBB->begin();
+ else {
+ I = BeforeI;
+ ++I;
+ }
+ }
+ }
}
+/// AdjustStackOffset - Helper function used to adjust the stack frame offset.
+static inline void
+AdjustStackOffset(MachineFrameInfo *FFI, 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);
+
+ unsigned Align = FFI->getObjectAlignment(FrameIdx);
+
+ // If the alignment of this object is greater than that of the stack, then
+ // increase the stack alignment to match.
+ MaxAlign = std::max(MaxAlign, Align);
+
+ // Adjust to alignment boundary.
+ Offset = (Offset + Align - 1) / Align * Align;
+
+ if (StackGrowsDown) {
+ FFI->setObjectOffset(FrameIdx, -Offset); // Set the computed offset
+ } else {
+ FFI->setObjectOffset(FrameIdx, Offset);
+ Offset += FFI->getObjectSize(FrameIdx);
+ }
+}
/// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the
/// abstract stack objects.
// Loop over all of the stack objects, assigning sequential addresses...
MachineFrameInfo *FFI = Fn.getFrameInfo();
- unsigned MaxAlign = 0;
+ unsigned MaxAlign = 1;
// Start at the beginning of the local area.
// The Offset is the distance from the stack top in the direction
- // of stack growth -- so it's always positive.
- int64_t Offset = TFI.getOffsetOfLocalArea();
+ // of stack growth -- so it's always nonnegative.
+ int LocalAreaOffset = TFI.getOffsetOfLocalArea();
if (StackGrowsDown)
- Offset = -Offset;
- assert(Offset >= 0
+ LocalAreaOffset = -LocalAreaOffset;
+ assert(LocalAreaOffset >= 0
&& "Local area offset should be in direction of stack growth");
+ int64_t Offset = LocalAreaOffset;
// If there are fixed sized objects that are preallocated in the local area,
// non-fixed objects can't be allocated right at the start of local area.
- // 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
+ // 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) {
int64_t FixedOff;
Offset += FFI->getObjectSize(i);
unsigned Align = FFI->getObjectAlignment(i);
- // If the alignment of this object is greater than that of the stack, then
- // increase the stack alignment to match.
+ // If the alignment of this object is greater than that of the stack,
+ // then increase the stack alignment to match.
MaxAlign = std::max(MaxAlign, Align);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
FFI->setObjectOffset(i, -Offset); // Set the computed offset
}
} else {
- for (unsigned i = MaxCSFrameIndex; i >= MinCSFrameIndex; --i) {
+ int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex;
+ for (int i = MaxCSFI; i >= MinCSFI ; --i) {
unsigned Align = FFI->getObjectAlignment(i);
- // If the alignment of this object is greater than that of the stack, then
- // increase the stack alignment to match.
+ // If the alignment of this object is greater than that of the stack,
+ // then increase the stack alignment to match.
MaxAlign = std::max(MaxAlign, Align);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
// Make sure the special register scavenging spill slot is closest to the
// frame pointer if a frame pointer is required.
- const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
+ const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
if (RS && RegInfo->hasFP(Fn)) {
int SFI = RS->getScavengingFrameIndex();
- if (SFI >= 0) {
- // If stack grows down, we need to add size of the lowest
- // address of the object.
- if (StackGrowsDown)
- Offset += FFI->getObjectSize(SFI);
-
- unsigned Align = FFI->getObjectAlignment(SFI);
- // Adjust to alignment boundary
- Offset = (Offset+Align-1)/Align*Align;
-
- if (StackGrowsDown) {
- FFI->setObjectOffset(SFI, -Offset); // Set the computed offset
- } else {
- FFI->setObjectOffset(SFI, Offset);
- Offset += FFI->getObjectSize(SFI);
- }
- }
+ if (SFI >= 0)
+ AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
}
+ // Make sure that the stack protector comes before the local variables on the
+ // stack.
+ if (FFI->getStackProtectorIndex() >= 0)
+ AdjustStackOffset(FFI, FFI->getStackProtectorIndex(), StackGrowsDown,
+ Offset, MaxAlign);
+
// 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) {
continue;
if (RS && (int)i == RS->getScavengingFrameIndex())
continue;
+ if (FFI->isDeadObjectIndex(i))
+ continue;
+ if (FFI->getStackProtectorIndex() == (int)i)
+ continue;
- // If stack grows down, we need to add size of find the lowest
- // address of the object.
- if (StackGrowsDown)
- Offset += FFI->getObjectSize(i);
-
- unsigned Align = FFI->getObjectAlignment(i);
- // If the alignment of this object is greater than that of the stack, then
- // increase the stack alignment to match.
- MaxAlign = std::max(MaxAlign, Align);
- // Adjust to alignment boundary
- Offset = (Offset+Align-1)/Align*Align;
-
- if (StackGrowsDown) {
- FFI->setObjectOffset(i, -Offset); // Set the computed offset
- } else {
- FFI->setObjectOffset(i, Offset);
- Offset += FFI->getObjectSize(i);
- }
+ AdjustStackOffset(FFI, i, StackGrowsDown, Offset, MaxAlign);
}
// Make sure the special register scavenging spill slot is closest to the
// stack pointer.
if (RS && !RegInfo->hasFP(Fn)) {
int SFI = RS->getScavengingFrameIndex();
- if (SFI >= 0) {
- // If stack grows down, we need to add size of find the lowest
- // address of the object.
- if (StackGrowsDown)
- Offset += FFI->getObjectSize(SFI);
-
- unsigned Align = FFI->getObjectAlignment(SFI);
- // Adjust to alignment boundary
- Offset = (Offset+Align-1)/Align*Align;
-
- if (StackGrowsDown) {
- FFI->setObjectOffset(SFI, -Offset); // Set the computed offset
- } else {
- FFI->setObjectOffset(SFI, Offset);
- Offset += FFI->getObjectSize(SFI);
- }
- }
+ if (SFI >= 0)
+ AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
}
- // Round up the size to a multiple of the alignment, but only if there are
- // calls or alloca's in the function. This ensures that any calls to
- // subroutines have their stack frames suitable aligned.
- if (!RegInfo->targetHandlesStackFrameRounding() &&
- (FFI->hasCalls() || FFI->hasVarSizedObjects())) {
+ if (!RegInfo->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 (RegInfo->hasReservedCallFrame(Fn))
+ if (FFI->hasCalls() && RegInfo->hasReservedCallFrame(Fn))
Offset += FFI->getMaxCallFrameSize();
- unsigned AlignMask = TFI.getStackAlignment() - 1;
+ // 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
+ // ensure that the callee's frame or the alloca data is suitably aligned;
+ // otherwise, for leaf functions, align to the TransientStackAlignment
+ // value.
+ unsigned StackAlign;
+ if (FFI->hasCalls() || FFI->hasVarSizedObjects() ||
+ (RegInfo->needsStackRealignment(Fn) && FFI->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.
+ 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+TFI.getOffsetOfLocalArea());
+ FFI->setStackSize(Offset - LocalAreaOffset);
// Remember the required stack alignment in case targets need it to perform
// dynamic stack alignment.
- assert(FFI->getMaxAlignment() == MaxAlign &&
- "Stack alignment calculation broken!");
+ if (MaxAlign > FFI->getMaxAlignment())
+ FFI->setMaxAlignment(MaxAlign);
}
/// prolog and epilog code to the function.
///
void PEI::insertPrologEpilogCode(MachineFunction &Fn) {
+ const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
+
// Add prologue to the function...
- Fn.getTarget().getRegisterInfo()->emitPrologue(Fn);
+ TRI->emitPrologue(Fn);
// Add epilogue to restore the callee-save registers in each exiting block
- const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
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() && TII.isReturn(I->back().getOpcode()))
- Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I);
+ if (!I->empty() && I->back().getDesc().isReturn())
+ TRI->emitEpilogue(Fn, *I);
}
}
const TargetMachine &TM = Fn.getTarget();
assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!");
- const MRegisterInfo &MRI = *TM.getRegisterInfo();
+ const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
const TargetFrameInfo *TFI = TM.getFrameInfo();
bool StackGrowsDown =
TFI->getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
- int FrameSetupOpcode = MRI.getCallFrameSetupOpcode();
- int FrameDestroyOpcode = MRI.getCallFrameDestroyOpcode();
+ int FrameSetupOpcode = TRI.getCallFrameSetupOpcode();
+ int FrameDestroyOpcode = TRI.getCallFrameDestroyOpcode();
- for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) {
+ for (MachineFunction::iterator BB = Fn.begin(),
+ E = Fn.end(); BB != E; ++BB) {
int SPAdj = 0; // SP offset due to call frame setup / destroy.
- if (RS) RS->enterBasicBlock(BB);
+ if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(BB);
+
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
- MachineInstr *MI = I;
- // Remember how much SP has been adjustment to create the call frame.
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
+ // Remember how much SP has been adjusted to create the call
+ // frame.
int Size = I->getOperand(0).getImm();
+
if ((!StackGrowsDown && I->getOpcode() == FrameSetupOpcode) ||
(StackGrowsDown && I->getOpcode() == FrameDestroyOpcode))
Size = -Size;
+
SPAdj += Size;
- MachineBasicBlock::iterator PrevI = prior(I);
- MRI.eliminateCallFramePseudoInstr(Fn, *BB, I);
+
+ MachineBasicBlock::iterator PrevI = BB->end();
+ if (I != BB->begin()) PrevI = prior(I);
+ TRI.eliminateCallFramePseudoInstr(Fn, *BB, I);
+
// Visit the instructions created by eliminateCallFramePseudoInstr().
- I = next(PrevI);
- MI = NULL;
- } else {
- I++;
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
- if (MI->getOperand(i).isFrameIndex()) {
- // If this instruction has a FrameIndex operand, we need to use that
- // target machine register info object to eliminate it.
- MRI.eliminateFrameIndex(MI, SPAdj, RS);
-
- // Revisit the instruction in full. Some instructions (e.g. inline
- // asm instructions) can have multiple frame indices.
- --I;
- MI = 0;
- break;
- }
+ if (PrevI == BB->end())
+ I = BB->begin(); // The replaced instr was the first in the block.
+ else
+ I = next(PrevI);
+ continue;
}
+
+ MachineInstr *MI = I;
+ bool DoIncr = true;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
+ if (MI->getOperand(i).isFI()) {
+ // Some instructions (e.g. inline asm instructions) can have
+ // multiple frame indices and/or cause eliminateFrameIndex
+ // to insert more than one instruction. We need the register
+ // scavenger to go through all of these instructions so that
+ // it can update its register information. We keep the
+ // iterator at the point before insertion so that we can
+ // revisit them in full.
+ bool AtBeginning = (I == BB->begin());
+ if (!AtBeginning) --I;
+
+ // 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);
+ }
+
+ // Reset the iterator if we were at the beginning of the BB.
+ if (AtBeginning) {
+ I = BB->begin();
+ DoIncr = false;
+ }
+
+ MI = 0;
+ break;
+ }
+
+ if (DoIncr && I != BB->end()) ++I;
+
// Update register states.
- if (RS && MI) RS->forward(MI);
+ if (RS && !FrameIndexVirtualScavenging && MI) RS->forward(MI);
}
+
assert(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, unsigned *Operand) {
+ // Scan forward to find the last use of this virtual register
+ for (++I; I != ME; ++I) {
+ MachineInstr *MI = I;
+ 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're done
+ if (MI->getOperand(i).isKill()) {
+ if (Operand)
+ *Operand = i;
+ 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.
+void PEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
+ // Run through the instructions and find any virtual registers.
+ for (MachineFunction::iterator BB = Fn.begin(),
+ E = Fn.end(); BB != E; ++BB) {
+ RS->enterBasicBlock(BB);
+
+ unsigned CurrentVirtReg = 0;
+ unsigned CurrentScratchReg = 0;
+ bool havePrevValue = false;
+ unsigned PrevScratchReg = 0;
+ int PrevValue = 0;
+ MachineInstr *PrevLastUseMI = NULL;
+ unsigned PrevLastUseOp = 0;
+ bool trackingCurrentValue = false;
+ 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(); ++I) {
+ MachineInstr *MI = I;
+ 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 an active scavenged register, we shouldn't be
+ // seeing any references to it.
+ assert (Reg != CurrentScratchReg
+ && "overlapping use of scavenged frame index register!");
+
+ // If we have a previous scratch reg, check and see if anything
+ // here kills whatever value is in there.
+ if (Reg == PrevScratchReg) {
+ if (MO.isUse()) {
+ // Two-address operands implicitly kill
+ if (MO.isKill() || MI->isRegTiedToDefOperand(i)) {
+ havePrevValue = false;
+ PrevScratchReg = 0;
+ }
+ } else {
+ assert (MO.isDef());
+ havePrevValue = false;
+ PrevScratchReg = 0;
+ }
+ }
+ continue;
+ }
+
+ // Have we already allocated a scratch register for this virtual?
+ if (Reg != CurrentVirtReg) {
+ // 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. Perhaps this implies that the frame index
+ // elimination should be before register allocation, with
+ // conservative heuristics since we'll know less then, and
+ // the reuse calculations done directly when doing the code-gen?
+
+ // 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, &i);
+ // Remove all instructions up 'til the last use, since they're
+ // just calculating the value we already have.
+ BB->erase(I, LastUseMI);
+ MI = I = LastUseMI;
+ e = MI->getNumOperands();
+
+ CurrentScratchReg = PrevScratchReg;
+ // Extend the live range of the register
+ PrevLastUseMI->getOperand(PrevLastUseOp).setIsKill(false);
+ RS->setUsed(CurrentScratchReg);
+ } else {
+ CurrentVirtReg = 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;
+ }
+ }
+ assert (CurrentScratchReg && "Missing scratch register!");
+ MI->getOperand(i).setReg(CurrentScratchReg);
+
+ // If this is the last use of the register, stop tracking it.
+ if (MI->getOperand(i).isKill()) {
+ PrevScratchReg = CurrentScratchReg;
+ PrevLastUseMI = MI;
+ PrevLastUseOp = i;
+ CurrentScratchReg = CurrentVirtReg = 0;
+ havePrevValue = trackingCurrentValue;
+ }
+ }
+ RS->forward(MI);
+ }
+ }
+}
projects / oota-llvm.git / blobdiff