//===-- PrologEpilogInserter.cpp - Insert Prolog/Epilog code in function --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
//
// This pass is responsible for finalizing the functions frame layout, saving
// callee saved registers, and for emitting prolog & epilog code for the
#include "llvm/Target/MRegisterInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
+using namespace llvm;
namespace {
struct PEI : public MachineFunctionPass {
};
}
+
/// createPrologEpilogCodeInserter - This function returns a pass that inserts
/// prolog and epilog code, and eliminates abstract frame references.
///
-Pass *createPrologEpilogCodeInserter() { return new PEI(); }
+FunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); }
/// saveCallerSavedRegisters - Scan the function for modified caller saved
return;
// This bitset contains an entry for each physical register for the target...
- std::vector<bool> ModifiedRegs(MRegisterInfo::FirstVirtualRegister);
+ std::vector<bool> ModifiedRegs(RegInfo->getNumRegs());
unsigned MaxCallFrameSize = 0;
bool HasCalls = false;
for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB)
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); )
- if ((*I)->getOpcode() == FrameSetupOpcode ||
- (*I)->getOpcode() == FrameDestroyOpcode) {
- assert((*I)->getNumOperands() == 1 && "Call Frame Setup/Destroy Pseudo"
+ if (I->getOpcode() == FrameSetupOpcode ||
+ I->getOpcode() == FrameDestroyOpcode) {
+ assert(I->getNumOperands() == 1 && "Call Frame Setup/Destroy Pseudo"
" instructions should have a single immediate argument!");
- unsigned Size = (*I)->getOperand(0).getImmedValue();
+ unsigned Size = I->getOperand(0).getImmedValue();
if (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
HasCalls = true;
- RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I);
+ RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I++);
} else {
- for (unsigned i = 0, e = (*I)->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = (*I)->getOperand(i);
- assert(!MO.isVirtualRegister() &&
- "Register allocation must be performed!");
- if (MO.isPhysicalRegister() &&
- (MO.opIsDefOnly() || MO.opIsDefAndUse()))
+ for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = I->getOperand(i);
+ if (MO.isRegister() && MO.isDef()) {
+ assert(MRegisterInfo::isPhysicalRegister(MO.getReg()) &&
+ "Register allocation must be performed!");
ModifiedRegs[MO.getReg()] = true; // Register is modified
- }
+ }
+ }
++I;
}
unsigned Reg = CSRegs[i];
if (ModifiedRegs[Reg]) {
RegsToSave.push_back(Reg); // If modified register...
- } else if (const unsigned *AliasSet = RegInfo->getAliasSet(Reg))
- for (unsigned j = 0; AliasSet[j]; ++j) // Check alias registers too...
- if (ModifiedRegs[AliasSet[j]]) {
+ } else {
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
+ *AliasSet; ++AliasSet) { // Check alias registers too...
+ if (ModifiedRegs[*AliasSet]) {
RegsToSave.push_back(Reg);
break;
}
+ }
+ }
}
if (RegsToSave.empty())
const TargetInstrInfo &TII = Fn.getTarget().getInstrInfo();
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; I = MBB->end()-1;
+ if (!FI->empty() && TII.isReturn(FI->back().getOpcode())) {
+ MBB = FI;
+ I = MBB->end(); --I;
for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) {
const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]);
unsigned StackAlignment = TFI.getStackAlignment();
- // Start at the beginning of the local area...
+ // Start at the beginning of the local area.
int Offset = TFI.getOffsetOfLocalArea();
+
+ // Check to see if there are any fixed sized objects that are preallocated in
+ // the local area. We currently don't support filling in holes in between
+ // fixed sized objects, so we just skip to the end of the last fixed sized
+ // preallocated object.
+ for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
+ int FixedOff = -FFI->getObjectOffset(i);
+ if (FixedOff > Offset) Offset = FixedOff;
+ }
+
for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
Offset += FFI->getObjectSize(i); // Allocate Size bytes...
FFI->setObjectOffset(i, -Offset); // Set the computed offset
}
- // Align the final stack pointer offset...
- Offset = (Offset+StackAlignment-1)/StackAlignment*StackAlignment;
+ // Align the final stack pointer offset, but only if there are calls in the
+ // function. This ensures that any calls to subroutines have their stack
+ // frames suitable aligned.
+ if (FFI->hasCalls())
+ Offset = (Offset+StackAlignment-1)/StackAlignment*StackAlignment;
// Set the final value of the stack pointer...
FFI->setStackSize(Offset-TFI.getOffsetOfLocalArea());
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()))
+ if (!I->empty() && TII.isReturn(I->back().getOpcode()))
Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I);
}
}
for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB)
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I)
- for (unsigned i = 0, e = (*I)->getNumOperands(); i != e; ++i)
- if ((*I)->getOperand(i).isFrameIndex()) {
+ for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
+ if (I->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(Fn, I);
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