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* Abstracted out stack space allocation into its own function

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* Added saving of register values to the stack


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4858 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Misha Brukman
2002-12-02 21:11:58 +00:00
parent 6877dd3fb0
commit f514d51b20
1 changed files with 36 additions and 34 deletions
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70
lib/CodeGen/RegAllocSimple.cpp
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@ -53,6 +53,10 @@ namespace {
return RegsUsed.find(Reg) == RegsUsed.end(); return RegsUsed.find(Reg) == RegsUsed.end();
} }
///
unsigned allocateStackSpaceFor(unsigned VirtReg,
const TargetRegisterClass *regClass);
/// Given size (in bytes), returns a register that is currently unused /// Given size (in bytes), returns a register that is currently unused
/// Side effect: marks that register as being used until manually cleared /// Side effect: marks that register as being used until manually cleared
unsigned getFreeReg(unsigned virtualReg); unsigned getFreeReg(unsigned virtualReg);
@ -84,6 +88,22 @@ namespace {
} }
unsigned RegAllocSimple::allocateStackSpaceFor(unsigned VirtReg,
const TargetRegisterClass *regClass)
{
if (RegMap.find(VirtReg) == RegMap.end()) {
unsigned size = regClass->getDataSize();
unsigned over = NumBytesAllocated - (NumBytesAllocated % ByteAlignment);
if (size >= ByteAlignment - over) {
// need to pad by (ByteAlignment - over)
NumBytesAllocated += ByteAlignment - over;
}
RegMap[VirtReg] = NumBytesAllocated;
NumBytesAllocated += size;
}
return RegMap[VirtReg];
}
unsigned RegAllocSimple::getFreeReg(unsigned virtualReg) { unsigned RegAllocSimple::getFreeReg(unsigned virtualReg) {
const TargetRegisterClass* regClass = MF->getRegClass(virtualReg); const TargetRegisterClass* regClass = MF->getRegClass(virtualReg);
unsigned physReg; unsigned physReg;
@ -112,29 +132,15 @@ RegAllocSimple::moveUseToReg (MachineBasicBlock::iterator I,
const TargetRegisterClass* regClass = MF->getRegClass(VirtReg); const TargetRegisterClass* regClass = MF->getRegClass(VirtReg);
assert(regClass); assert(regClass);
unsigned stackOffset; unsigned stackOffset = allocateStackSpaceFor(VirtReg, regClass);
if (RegMap.find(VirtReg) == RegMap.end()) {
unsigned size = regClass->getDataSize();
unsigned over = NumBytesAllocated - (NumBytesAllocated % ByteAlignment);
if (size >= ByteAlignment - over) {
// need to pad by (ByteAlignment - over)
NumBytesAllocated += ByteAlignment - over;
}
RegMap[VirtReg] = NumBytesAllocated;
NumBytesAllocated += size;
}
stackOffset = RegMap[VirtReg];
PhysReg = getFreeReg(VirtReg); PhysReg = getFreeReg(VirtReg);
// Add move instruction(s)
MachineBasicBlock::iterator newI =
RegInfo->loadRegOffset2Reg(CurrMBB, I, PhysReg,
RegInfo->getFramePointer(),
stackOffset, regClass->getDataSize());
// FIXME: increment the frame pointer // FIXME: increment the frame pointer
return newI; // Add move instruction(s)
return RegInfo->loadRegOffset2Reg(CurrMBB, I, PhysReg,
RegInfo->getFramePointer(),
stackOffset, regClass->getDataSize());
} }
MachineBasicBlock::iterator MachineBasicBlock::iterator
@ -143,10 +149,9 @@ RegAllocSimple::saveRegToStack (MachineBasicBlock::iterator I,
{ {
const TargetRegisterClass* regClass = MF->getRegClass(VirtReg); const TargetRegisterClass* regClass = MF->getRegClass(VirtReg);
assert(regClass); assert(regClass);
assert(RegMap.find(VirtReg) != RegMap.end() &&
"Virtual reg has no stack offset mapping!");
unsigned offset = RegMap[VirtReg]; unsigned offset = allocateStackSpaceFor(VirtReg, regClass);
// Add move instruction(s) // Add move instruction(s)
return RegInfo->storeReg2RegOffset(CurrMBB, I, PhysReg, return RegInfo->storeReg2RegOffset(CurrMBB, I, PhysReg,
RegInfo->getFramePointer(), RegInfo->getFramePointer(),
@ -165,7 +170,6 @@ bool RegAllocSimple::runOnMachineFunction(MachineFunction &Fn) {
{ {
CurrMBB = &(*MBB); CurrMBB = &(*MBB);
// FIXME: if return, special case => into return register
//loop over each basic block //loop over each basic block
for (MachineBasicBlock::iterator I = MBB->begin(); I != MBB->end(); ++I) for (MachineBasicBlock::iterator I = MBB->begin(); I != MBB->end(); ++I)
{ {
@ -185,20 +189,18 @@ bool RegAllocSimple::runOnMachineFunction(MachineFunction &Fn) {
DEBUG(std::cerr << "const\n"); DEBUG(std::cerr << "const\n");
} else if (op.isVirtualRegister()) { } else if (op.isVirtualRegister()) {
virtualReg = (unsigned) op.getAllocatedRegNum(); virtualReg = (unsigned) op.getAllocatedRegNum();
#if 0 // save register to stack if it's a def
// FIXME: save register to stack
if (op.opIsDef()) {
MachineBasicBlock::iterator J = I;
saveRegToStack(++J, virtualReg, physReg);
}
#endif
DEBUG(std::cerr << "op: " << op << "\n"); DEBUG(std::cerr << "op: " << op << "\n");
DEBUG(std::cerr << "\t inst[" << i << "]: "; DEBUG(std::cerr << "\t inst[" << i << "]: ";
MI->print(std::cerr, TM)); MI->print(std::cerr, TM));
I = moveUseToReg(I, virtualReg, physReg); if (op.opIsDef()) {
//MI = *I; physReg = getFreeReg(virtualReg);
bool def = op.opIsDef() || op.opIsDefAndUse(); MachineBasicBlock::iterator J = I;
MI->SetMachineOperandReg(i, physReg, def); I = saveRegToStack(++J, virtualReg, physReg);
} else {
I = moveUseToReg(I, virtualReg, physReg);
}
MI->SetMachineOperandReg(i, physReg);
DEBUG(std::cerr << "virt: " << virtualReg << DEBUG(std::cerr << "virt: " << virtualReg <<
", phys: " << op.getAllocatedRegNum() << "\n"); ", phys: " << op.getAllocatedRegNum() << "\n");
} }