llvm-6502/lib/Target/SparcV9/SparcV9RegClassInfo.cpp

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//===-- SparcV9RegClassInfo.cpp - Register class def'ns for SparcV9 -------===//
//
// 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 file defines the methods used by the SparcV9 register allocator
// to pick registers of various classes. Most of this code should be
// considered part of the register allocator.
//
//===----------------------------------------------------------------------===//
#include "llvm/Type.h"
#include "SparcV9RegClassInfo.h"
#include "SparcV9Internals.h"
#include "SparcV9RegInfo.h"
#include "RegAlloc/RegAllocCommon.h"
#include "RegAlloc/IGNode.h"
#include <iostream>
namespace llvm {
//-----------------------------------------------------------------------------
// Int Register Class - method for coloring a node in the interference graph.
//
// Algorithm:
// Record the colors/suggested colors of all neighbors.
//
// If there is a suggested color, try to allocate it
// If there is no call interf, try to allocate volatile, then non volatile
// If there is call interf, try to allocate non-volatile. If that fails
// try to allocate a volatile and insert save across calls
// If both above fail, spill.
//
//-----------------------------------------------------------------------------
void SparcV9IntRegClass::colorIGNode(IGNode * Node,
const std::vector<bool> &IsColorUsedArr) const
{
LiveRange *LR = Node->getParentLR();
if (DEBUG_RA)
std::cerr << "\nColoring LR [CallInt=" << LR->isCallInterference() <<"]:"
<< *LR << "\n";
if (LR->hasSuggestedColor()) {
unsigned SugCol = LR->getSuggestedColor();
if (!IsColorUsedArr[SugCol]) {
if (LR->isSuggestedColorUsable()) {
// if the suggested color is volatile, we should use it only if
// there are no call interferences. Otherwise, it will get spilled.
if (DEBUG_RA)
std::cerr << "\n -Coloring with sug color: " << SugCol;
LR->setColor(LR->getSuggestedColor());
return;
} else if(DEBUG_RA) {
std::cerr << "\n Couldn't alloc Sug col - LR volatile & calls interf";
}
} else if (DEBUG_RA) { // can't allocate the suggested col
std::cerr << "\n Could NOT allocate the suggested color (already used) "
<< *LR << "\n";
}
}
unsigned SearchStart; // start pos of color in pref-order
bool ColorFound= false; // have we found a color yet?
//if this Node is between calls
if (! LR->isCallInterference()) {
// start with volatiles (we can allocate volatiles safely)
SearchStart = SparcV9IntRegClass::StartOfAllRegs;
} else {
// start with non volatiles (no non-volatiles)
SearchStart = SparcV9IntRegClass::StartOfNonVolatileRegs;
}
unsigned c=0; // color
// find first unused color
for (c=SearchStart; c < SparcV9IntRegClass::NumOfAvailRegs; c++) {
if (!IsColorUsedArr[c]) {
ColorFound = true;
break;
}
}
if (ColorFound) {
LR->setColor(c); // first color found in preferred order
if (DEBUG_RA) std::cerr << "\n Colored after first search with col " << c;
}
// if color is not found because of call interference
// try even finding a volatile color and insert save across calls
//
else if (LR->isCallInterference()) {
// start from 0 - try to find even a volatile this time
SearchStart = SparcV9IntRegClass::StartOfAllRegs;
// find first unused volatile color
for(c=SearchStart; c < SparcV9IntRegClass::StartOfNonVolatileRegs; c++) {
if (! IsColorUsedArr[c]) {
ColorFound = true;
break;
}
}
if (ColorFound) {
LR->setColor(c);
// get the live range corresponding to live var
// since LR span across calls, must save across calls
//
if (DEBUG_RA)
std::cerr << "\n Colored after SECOND search with col " << c;
}
}
// If we couldn't find a color regardless of call interference - i.e., we
// don't have either a volatile or non-volatile color left
//
if (!ColorFound)
LR->markForSpill(); // no color found - must spill
}
//-----------------------------------------------------------------------------
// Int CC Register Class - method for coloring a node in the interference graph.
//
// Algorithm:
//
// If (node has any interferences)
// /* all interference operations can use only one register! */
// mark the LR for spilling
// else {
// if (the LR is a 64-bit comparison) use %xcc
// else /*32-bit or smaller*/ use %icc
// }
//
// Note: The third name (%ccr) is essentially an assembly mnemonic and
// depends solely on the opcode, so the name can be chosen in EmitAssembly.
//-----------------------------------------------------------------------------
void SparcV9IntCCRegClass::colorIGNode(IGNode *Node,
const std::vector<bool> &IsColorUsedArr) const
{
if (Node->getNumOfNeighbors() > 0)
Node->getParentLR()->markForSpill();
// Mark the appropriate register in any case (even if it needs to be spilled)
// because there is only one possible register, but more importantly, the
// spill algorithm cannot find it. In particular, we have to choose
// whether to use %xcc or %icc based on type of value compared
//
const LiveRange* ccLR = Node->getParentLR();
const Type* setCCType = (* ccLR->begin())->getType(); // any Value in LR
assert(setCCType->isIntegral() || isa<PointerType>(setCCType));
int ccReg = ((isa<PointerType>(setCCType) || setCCType == Type::LongTy)
? xcc : icc);
#ifndef NDEBUG
// Let's just make sure values of two different types have not been
// coalesced into this LR.
for (LiveRange::const_iterator I=ccLR->begin(), E=ccLR->end(); I!=E; ++I) {
const Type* ccType = (*I)->getType();
assert((ccReg == xcc && (isa<PointerType>(ccType)
|| ccType == Type::LongTy)) ||
(ccReg == icc && ccType->isIntegral() && ccType != Type::LongTy)
&& "Comparisons needing different intCC regs coalesced in LR!");
}
#endif
Node->setColor(ccReg); // only one int cc reg is available
}
void SparcV9FloatCCRegClass::colorIGNode(IGNode *Node,
const std::vector<bool> &IsColorUsedArr) const {
for(unsigned c = 0; c != 4; ++c)
if (!IsColorUsedArr[c]) { // find unused color
Node->setColor(c);
return;
}
Node->getParentLR()->markForSpill();
}
//-----------------------------------------------------------------------------
// Float Register Class - method for coloring a node in the interference graph.
//
// Algorithm:
//
// If the LR is a double try to allocate f32 - f63
// If the above fails or LR is single precision
// If the LR does not interfere with a call
// start allocating from f0
// Else start allocating from f6
// If a color is still not found because LR interferes with a call
// Search in f0 - f6. If found mark for spill across calls.
// If a color is still not fond, mark for spilling
//
//----------------------------------------------------------------------------
void SparcV9FloatRegClass::colorIGNode(IGNode * Node,
const std::vector<bool> &IsColorUsedArr) const
{
LiveRange *LR = Node->getParentLR();
#ifndef NDEBUG
// Check that the correct colors have been are marked for fp-doubles.
//
// FIXME: This is old code that is no longer needed. Temporarily converting
// it into a big assertion just to check that the replacement logic
// (invoking SparcV9FloatRegClass::markColorsUsed() directly from
// RegClass::colorIGNode) works correctly.
//
// In fact, this entire function should be identical to
// SparcV9IntRegClass::colorIGNode(), and perhaps can be
// made into a general case in CodeGen/RegAlloc/RegClass.cpp.
//
unsigned NumNeighbors = Node->getNumOfNeighbors(); // total # of neighbors
for(unsigned n=0; n < NumNeighbors; n++) { // for each neigh
IGNode *NeighIGNode = Node->getAdjIGNode(n);
LiveRange *NeighLR = NeighIGNode->getParentLR();
if (NeighLR->hasColor()) {
assert(IsColorUsedArr[ NeighLR->getColor() ]);
if (NeighLR->getType() == Type::DoubleTy)
assert(IsColorUsedArr[ NeighLR->getColor()+1 ]);
} else if (NeighLR->hasSuggestedColor() &&
NeighLR-> isSuggestedColorUsable() ) {
// if the neighbour can use the suggested color
assert(IsColorUsedArr[ NeighLR->getSuggestedColor() ]);
if (NeighLR->getType() == Type::DoubleTy)
assert(IsColorUsedArr[ NeighLR->getSuggestedColor()+1 ]);
}
}
#endif
// **NOTE: We don't check for call interferences in allocating suggested
// color in this class since ALL registers are volatile. If this fact
// changes, we should change the following part
//- see SparcV9IntRegClass::colorIGNode()
//
if( LR->hasSuggestedColor() ) {
if( ! IsColorUsedArr[ LR->getSuggestedColor() ] ) {
LR->setColor( LR->getSuggestedColor() );
return;
} else if (DEBUG_RA) { // can't allocate the suggested col
std::cerr << " Could NOT allocate the suggested color for LR " << *LR
<< "\n";
}
}
int ColorFound = -1; // have we found a color yet?
bool isCallInterf = LR->isCallInterference();
// if value is a double - search the double only region (f32 - f63)
// i.e. we try to allocate f32 - f63 first for doubles since singles
// cannot go there. By doing that, we provide more space for singles
// in f0 - f31
//
if (LR->getType() == Type::DoubleTy)
ColorFound = findFloatColor( LR, 32, 64, IsColorUsedArr );
if (ColorFound >= 0) { // if we could find a color
LR->setColor(ColorFound);
return;
} else {
// if we didn't find a color because the LR was single precision or
// all f32-f63 range is filled, we try to allocate a register from
// the f0 - f31 region
unsigned SearchStart; // start pos of color in pref-order
//if this Node is between calls (i.e., no call interferences )
if (! isCallInterf) {
// start with volatiles (we can allocate volatiles safely)
SearchStart = SparcV9FloatRegClass::StartOfAllRegs;
} else {
// start with non volatiles (no non-volatiles)
SearchStart = SparcV9FloatRegClass::StartOfNonVolatileRegs;
}
ColorFound = findFloatColor(LR, SearchStart, 32, IsColorUsedArr);
}
if (ColorFound >= 0) { // if we could find a color
LR->setColor(ColorFound);
return;
} else if (isCallInterf) {
// We are here because there is a call interference and no non-volatile
// color could be found.
// Now try to allocate even a volatile color
ColorFound = findFloatColor(LR, SparcV9FloatRegClass::StartOfAllRegs,
SparcV9FloatRegClass::StartOfNonVolatileRegs,
IsColorUsedArr);
}
if (ColorFound >= 0) {
LR->setColor(ColorFound); // first color found in preferred order
} else {
// we are here because no color could be found
LR->markForSpill(); // no color found - must spill
}
}
//-----------------------------------------------------------------------------
// This method marks the registers used for a given register number.
// This marks a single register for Float regs, but the R,R+1 pair
// for double-precision registers.
//-----------------------------------------------------------------------------
void SparcV9FloatRegClass::markColorsUsed(unsigned RegInClass,
int UserRegType,
int RegTypeWanted,
std::vector<bool> &IsColorUsedArr) const
{
if (UserRegType == SparcV9RegInfo::FPDoubleRegType ||
RegTypeWanted == SparcV9RegInfo::FPDoubleRegType) {
// This register is used as or is needed as a double-precision reg.
// We need to mark the [even,odd] pair corresponding to this reg.
// Get the even numbered register corresponding to this reg.
unsigned EvenRegInClass = RegInClass & ~1u;
assert(EvenRegInClass+1 < NumOfAllRegs &&
EvenRegInClass+1 < IsColorUsedArr.size());
IsColorUsedArr[EvenRegInClass] = true;
IsColorUsedArr[EvenRegInClass+1] = true;
}
else {
assert(RegInClass < NumOfAllRegs && RegInClass < IsColorUsedArr.size());
assert(UserRegType == RegTypeWanted
&& "Something other than FP single/double types share a reg class?");
IsColorUsedArr[RegInClass] = true;
}
}
// This method finds unused registers of the specified register type,
// using the given "used" flag array IsColorUsedArr. It checks a single
// entry in the array directly for float regs, and checks the pair [R,R+1]
// for double-precision registers
// It returns -1 if no unused color is found.
//
int SparcV9FloatRegClass::findUnusedColor(int RegTypeWanted,
const std::vector<bool> &IsColorUsedArr) const
{
if (RegTypeWanted == SparcV9RegInfo::FPDoubleRegType) {
unsigned NC = 2 * this->getNumOfAvailRegs();
assert(IsColorUsedArr.size() == NC && "Invalid colors-used array");
for (unsigned c = 0; c < NC; c+=2)
if (!IsColorUsedArr[c]) {
assert(!IsColorUsedArr[c+1] && "Incorrect used regs for FP double!");
return c;
}
return -1;
}
else
return TargetRegClassInfo::findUnusedColor(RegTypeWanted, IsColorUsedArr);
}
//-----------------------------------------------------------------------------
// Helper method for coloring a node of Float Reg class.
// Finds the first available color in the range [Start,End] depending on the
// type of the Node (i.e., float/double)
//-----------------------------------------------------------------------------
int SparcV9FloatRegClass::findFloatColor(const LiveRange *LR,
unsigned Start,
unsigned End,
const std::vector<bool> &IsColorUsedArr) const
{
if (LR->getType() == Type::DoubleTy) {
// find first unused color for a double
assert(Start % 2 == 0 && "Odd register number could be used for double!");
for (unsigned c=Start; c < End ; c+= 2)
if (!IsColorUsedArr[c]) {
assert(!IsColorUsedArr[c+1] &&
"Incorrect marking of used regs for SparcV9 FP double!");
return c;
}
} else {
// find first unused color for a single
for (unsigned c = Start; c < End; c++)
if (!IsColorUsedArr[c])
return c;
}
return -1;
}
} // End llvm namespace