// 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.
-//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "pei"
STATISTIC(NumBytesStackSpace,
"Number of bytes used for stack in all functions");
+void PEI::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ AU.addPreserved<MachineLoopInfo>();
+ AU.addPreserved<MachineDominatorTree>();
+ AU.addRequired<TargetPassConfig>();
+ MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+bool PEI::isReturnBlock(MachineBasicBlock* MBB) {
+ return (MBB && !MBB->empty() && MBB->back().isReturn());
+}
+
+/// Compute the set of return blocks
+void PEI::calculateSets(MachineFunction &Fn) {
+ // Sets used to compute spill, restore placement sets.
+ const std::vector<CalleeSavedInfo> &CSI =
+ Fn.getFrameInfo()->getCalleeSavedInfo();
+
+ // If no CSRs used, we are done.
+ if (CSI.empty())
+ return;
+
+ // Save refs to entry and return blocks.
+ EntryBlock = Fn.begin();
+ for (MachineFunction::iterator MBB = Fn.begin(), E = Fn.end();
+ MBB != E; ++MBB)
+ if (isReturnBlock(MBB))
+ ReturnBlocks.push_back(MBB);
+
+ return;
+}
+
/// runOnMachineFunction - Insert prolog/epilog code and replace abstract
/// frame indexes with appropriate references.
///
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 shink wrapping (default), place all spills in the
- // entry block, all restores in return blocks.
- placeCSRSpillsAndRestores(Fn);
+ // place all spills in the entry block, all restores in return blocks.
+ calculateSets(Fn);
// Add the code to save and restore the callee saved registers
if (!F->hasFnAttribute(Attribute::Naked))
<< ") in " << Fn.getName() << ".\n";
delete RS;
- clearAllSets();
+ ReturnBlocks.clear();
return true;
}
}
/// insertCSRSpillsAndRestores - Insert spill and restore code for
-/// callee saved registers used in the function, handling shrink wrapping.
+/// callee saved registers used in the function.
///
void PEI::insertCSRSpillsAndRestores(MachineFunction &Fn) {
// Get callee saved register information.
const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
MachineBasicBlock::iterator I;
- if (!ShrinkWrapThisFunction) {
- // Spill using target interface.
- I = EntryBlock->begin();
- 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.
- unsigned Reg = CSI[i].getReg();
- const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.storeRegToStackSlot(*EntryBlock, I, Reg, true,
- CSI[i].getFrameIdx(), RC, TRI);
- }
- }
-
- // 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() && (--I2)->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 precede it.
- if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) {
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- unsigned Reg = CSI[i].getReg();
- const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.loadRegFromStackSlot(*MBB, I, Reg,
- CSI[i].getFrameIdx(),
- RC, TRI);
- 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;
- }
- }
- }
- }
- 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) {
+ // Spill using target interface.
+ I = EntryBlock->begin();
+ 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.
- MBB->addLiveIn(blockCSI[i].getReg());
+ EntryBlock->addLiveIn(CSI[i].getReg());
// Insert the spill to the stack frame.
- unsigned Reg = blockCSI[i].getReg();
+ unsigned Reg = CSI[i].getReg();
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.storeRegToStackSlot(*MBB, I, Reg,
- true,
- blockCSI[i].getFrameIdx(),
+ TII.storeRegToStackSlot(*EntryBlock, I, Reg, true, CSI[i].getFrameIdx(),
RC, TRI);
}
}
- for (CSRegBlockMap::iterator BI = CSRRestore.begin(),
- BE = CSRRestore.end(); BI != BE; ++BI) {
- MachineBasicBlock* MBB = BI->first;
- CSRegSet restore = BI->second;
-
- if (restore.empty())
- continue;
+ // Restore using target interface.
+ for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri) {
+ MachineBasicBlock *MBB = ReturnBlocks[ri];
+ I = MBB->end();
+ --I;
- 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->isTerminator()) {
- ++I;
- } else {
- MachineBasicBlock::iterator I2 = I;
- while (I2 != MBB->begin() && (--I2)->isTerminator())
- I = I2;
- }
- }
+ // Skip over all terminator instructions, which are part of the return
+ // sequence.
+ MachineBasicBlock::iterator I2 = I;
+ while (I2 != MBB->begin() && (--I2)->isTerminator())
+ I = I2;
bool AtStart = I == MBB->begin();
MachineBasicBlock::iterator BeforeI = I;
// Restore all registers immediately before the return and any
// terminators that precede it.
- for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
- unsigned Reg = blockCSI[i].getReg();
- const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.loadRegFromStackSlot(*MBB, I, Reg,
- blockCSI[i].getFrameIdx(),
- RC, TRI);
- 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;
+ if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) {
+ for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
+ unsigned Reg = CSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.loadRegFromStackSlot(*MBB, I, Reg, CSI[i].getFrameIdx(), RC, TRI);
+ 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;
+ }
}
}
}
projects / oota-llvm.git / blobdiff