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llvm-6502/lib/CodeGen/MachineFunction.cpp
Rafael Espindola 95d594cac3 Teach CodeGen's version of computeMaskedBits to understand the range metadata. 
This is the CodeGen equivalent of r153747. I tested that there is not noticeable
performance difference with any combination of -O0/-O2 /-g when compiling
gcc as a single compilation unit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153817 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-31 18:14:00 +00:00

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//===-- MachineFunction.cpp -----------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Collect native machine code information for a function. This allows
// target-specific information about the generated code to be stored with each
// function.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// MachineFunction implementation
//===----------------------------------------------------------------------===//
// Out of line virtual method.
MachineFunctionInfo::~MachineFunctionInfo() {}
void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
MBB->getParent()->DeleteMachineBasicBlock(MBB);
}
MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
unsigned FunctionNum, MachineModuleInfo &mmi,
GCModuleInfo* gmi)
: Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
if (TM.getRegisterInfo())
RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
else
RegInfo = 0;
MFInfo = 0;
FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameLowering());
if (Fn->hasFnAttr(Attribute::StackAlignment))
FrameInfo->setMaxAlignment(Attribute::getStackAlignmentFromAttrs(
Fn->getAttributes().getFnAttributes()));
ConstantPool = new (Allocator) MachineConstantPool(TM.getTargetData());
Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
// FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
if (!Fn->hasFnAttr(Attribute::OptimizeForSize))
Alignment = std::max(Alignment,
TM.getTargetLowering()->getPrefFunctionAlignment());
FunctionNumber = FunctionNum;
JumpTableInfo = 0;
}
MachineFunction::~MachineFunction() {
BasicBlocks.clear();
InstructionRecycler.clear(Allocator);
BasicBlockRecycler.clear(Allocator);
if (RegInfo) {
RegInfo->~MachineRegisterInfo();
Allocator.Deallocate(RegInfo);
}
if (MFInfo) {
MFInfo->~MachineFunctionInfo();
Allocator.Deallocate(MFInfo);
}
FrameInfo->~MachineFrameInfo(); Allocator.Deallocate(FrameInfo);
ConstantPool->~MachineConstantPool(); Allocator.Deallocate(ConstantPool);
if (JumpTableInfo) {
JumpTableInfo->~MachineJumpTableInfo();
Allocator.Deallocate(JumpTableInfo);
}
}
/// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
/// does already exist, allocate one.
MachineJumpTableInfo *MachineFunction::
getOrCreateJumpTableInfo(unsigned EntryKind) {
if (JumpTableInfo) return JumpTableInfo;
JumpTableInfo = new (Allocator)
MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
return JumpTableInfo;
}
/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
/// recomputes them. This guarantees that the MBB numbers are sequential,
/// dense, and match the ordering of the blocks within the function. If a
/// specific MachineBasicBlock is specified, only that block and those after
/// it are renumbered.
void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
if (empty()) { MBBNumbering.clear(); return; }
MachineFunction::iterator MBBI, E = end();
if (MBB == 0)
MBBI = begin();
else
MBBI = MBB;
// Figure out the block number this should have.
unsigned BlockNo = 0;
if (MBBI != begin())
BlockNo = prior(MBBI)->getNumber()+1;
for (; MBBI != E; ++MBBI, ++BlockNo) {
if (MBBI->getNumber() != (int)BlockNo) {
// Remove use of the old number.
if (MBBI->getNumber() != -1) {
assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
"MBB number mismatch!");
MBBNumbering[MBBI->getNumber()] = 0;
}
// If BlockNo is already taken, set that block's number to -1.
if (MBBNumbering[BlockNo])
MBBNumbering[BlockNo]->setNumber(-1);
MBBNumbering[BlockNo] = MBBI;
MBBI->setNumber(BlockNo);
}
}
// Okay, all the blocks are renumbered. If we have compactified the block
// numbering, shrink MBBNumbering now.
assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
MBBNumbering.resize(BlockNo);
}
/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
/// of `new MachineInstr'.
///
MachineInstr *
MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
DebugLoc DL, bool NoImp) {
return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
MachineInstr(MCID, DL, NoImp);
}
/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
/// 'Orig' instruction, identical in all ways except the instruction
/// has no parent, prev, or next.
///
MachineInstr *
MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
MachineInstr(*this, *Orig);
}
/// DeleteMachineInstr - Delete the given MachineInstr.
///
void
MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
MI->~MachineInstr();
InstructionRecycler.Deallocate(Allocator, MI);
}
/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
/// instead of `new MachineBasicBlock'.
///
MachineBasicBlock *
MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
MachineBasicBlock(*this, bb);
}
/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
///
void
MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
assert(MBB->getParent() == this && "MBB parent mismatch!");
MBB->~MachineBasicBlock();
BasicBlockRecycler.Deallocate(Allocator, MBB);
}
MachineMemOperand *
MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
uint64_t s, unsigned base_alignment,
const MDNode *TBAAInfo,
const MDNode *Ranges) {
return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
TBAAInfo, Ranges);
}
MachineMemOperand *
MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
int64_t Offset, uint64_t Size) {
return new (Allocator)
MachineMemOperand(MachinePointerInfo(MMO->getValue(),
MMO->getOffset()+Offset),
MMO->getFlags(), Size,
MMO->getBaseAlignment(), 0);
}
MachineInstr::mmo_iterator
MachineFunction::allocateMemRefsArray(unsigned long Num) {
return Allocator.Allocate<MachineMemOperand *>(Num);
}
std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
MachineInstr::mmo_iterator End) {
// Count the number of load mem refs.
unsigned Num = 0;
for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
if ((*I)->isLoad())
++Num;
// Allocate a new array and populate it with the load information.
MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
unsigned Index = 0;
for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
if ((*I)->isLoad()) {
if (!(*I)->isStore())
// Reuse the MMO.
Result[Index] = *I;
else {
// Clone the MMO and unset the store flag.
MachineMemOperand *JustLoad =
getMachineMemOperand((*I)->getPointerInfo(),
(*I)->getFlags() & ~MachineMemOperand::MOStore,
(*I)->getSize(), (*I)->getBaseAlignment(),
(*I)->getTBAAInfo());
Result[Index] = JustLoad;
}
++Index;
}
}
return std::make_pair(Result, Result + Num);
}
std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
MachineInstr::mmo_iterator End) {
// Count the number of load mem refs.
unsigned Num = 0;
for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
if ((*I)->isStore())
++Num;
// Allocate a new array and populate it with the store information.
MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
unsigned Index = 0;
for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
if ((*I)->isStore()) {
if (!(*I)->isLoad())
// Reuse the MMO.
Result[Index] = *I;
else {
// Clone the MMO and unset the load flag.
MachineMemOperand *JustStore =
getMachineMemOperand((*I)->getPointerInfo(),
(*I)->getFlags() & ~MachineMemOperand::MOLoad,
(*I)->getSize(), (*I)->getBaseAlignment(),
(*I)->getTBAAInfo());
Result[Index] = JustStore;
}
++Index;
}
}
return std::make_pair(Result, Result + Num);
}
void MachineFunction::dump() const {
print(dbgs());
}
void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
OS << "# Machine code for function " << Fn->getName() << ": ";
if (RegInfo) {
OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
if (!RegInfo->tracksLiveness())
OS << ", not tracking liveness";
}
OS << '\n';
// Print Frame Information
FrameInfo->print(*this, OS);
// Print JumpTable Information
if (JumpTableInfo)
JumpTableInfo->print(OS);
// Print Constant Pool
ConstantPool->print(OS);
const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
if (RegInfo && !RegInfo->livein_empty()) {
OS << "Function Live Ins: ";
for (MachineRegisterInfo::livein_iterator
I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
OS << PrintReg(I->first, TRI);
if (I->second)
OS << " in " << PrintReg(I->second, TRI);
if (llvm::next(I) != E)
OS << ", ";
}
OS << '\n';
}
if (RegInfo && !RegInfo->liveout_empty()) {
OS << "Function Live Outs:";
for (MachineRegisterInfo::liveout_iterator
I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
OS << ' ' << PrintReg(*I, TRI);
OS << '\n';
}
for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
OS << '\n';
BB->print(OS, Indexes);
}
OS << "\n# End machine code for function " << Fn->getName() << ".\n\n";
}
namespace llvm {
template<>
struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
static std::string getGraphName(const MachineFunction *F) {
return "CFG for '" + F->getFunction()->getName().str() + "' function";
}
std::string getNodeLabel(const MachineBasicBlock *Node,
const MachineFunction *Graph) {
std::string OutStr;
{
raw_string_ostream OSS(OutStr);
if (isSimple()) {
OSS << "BB#" << Node->getNumber();
if (const BasicBlock *BB = Node->getBasicBlock())
OSS << ": " << BB->getName();
} else
Node->print(OSS);
}
if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
// Process string output to make it nicer...
for (unsigned i = 0; i != OutStr.length(); ++i)
if (OutStr[i] == '\n') { // Left justify
OutStr[i] = '\\';
OutStr.insert(OutStr.begin()+i+1, 'l');
}
return OutStr;
}
};
}
void MachineFunction::viewCFG() const
{
#ifndef NDEBUG
ViewGraph(this, "mf" + getFunction()->getName());
#else
errs() << "MachineFunction::viewCFG is only available in debug builds on "
<< "systems with Graphviz or gv!\n";
#endif // NDEBUG
}
void MachineFunction::viewCFGOnly() const
{
#ifndef NDEBUG
ViewGraph(this, "mf" + getFunction()->getName(), true);
#else
errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
<< "systems with Graphviz or gv!\n";
#endif // NDEBUG
}
/// addLiveIn - Add the specified physical register as a live-in value and
/// create a corresponding virtual register for it.
unsigned MachineFunction::addLiveIn(unsigned PReg,
const TargetRegisterClass *RC) {
MachineRegisterInfo &MRI = getRegInfo();
unsigned VReg = MRI.getLiveInVirtReg(PReg);
if (VReg) {
assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
return VReg;
}
VReg = MRI.createVirtualRegister(RC);
MRI.addLiveIn(PReg, VReg);
return VReg;
}
/// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
/// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
/// normal 'L' label is returned.
MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
bool isLinkerPrivate) const {
assert(JumpTableInfo && "No jump tables");
assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
MAI.getPrivateGlobalPrefix();
SmallString<60> Name;
raw_svector_ostream(Name)
<< Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
return Ctx.GetOrCreateSymbol(Name.str());
}
/// getPICBaseSymbol - Return a function-local symbol to represent the PIC
/// base.
MCSymbol *MachineFunction::getPICBaseSymbol() const {
const MCAsmInfo &MAI = *Target.getMCAsmInfo();
return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
Twine(getFunctionNumber())+"$pb");
}
//===----------------------------------------------------------------------===//
// MachineFrameInfo implementation
//===----------------------------------------------------------------------===//
/// CreateFixedObject - Create a new object at a fixed location on the stack.
/// All fixed objects should be created before other objects are created for
/// efficiency. By default, fixed objects are immutable. This returns an
/// index with a negative value.
///
int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
bool Immutable) {
assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
// The alignment of the frame index can be determined from its offset from
// the incoming frame position. If the frame object is at offset 32 and
// the stack is guaranteed to be 16-byte aligned, then we know that the
// object is 16-byte aligned.
unsigned StackAlign = TFI.getStackAlignment();
unsigned Align = MinAlign(SPOffset, StackAlign);
Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
/*isSS*/false, false));
return -++NumFixedObjects;
}
BitVector
MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
assert(MBB && "MBB must be valid");
const MachineFunction *MF = MBB->getParent();
assert(MF && "MBB must be part of a MachineFunction");
const TargetMachine &TM = MF->getTarget();
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
BitVector BV(TRI->getNumRegs());
// Before CSI is calculated, no registers are considered pristine. They can be
// freely used and PEI will make sure they are saved.
if (!isCalleeSavedInfoValid())
return BV;
for (const uint16_t *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
BV.set(*CSR);
// The entry MBB always has all CSRs pristine.
if (MBB == &MF->front())
return BV;
// On other MBBs the saved CSRs are not pristine.
const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
E = CSI.end(); I != E; ++I)
BV.reset(I->getReg());
return BV;
}
void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
if (Objects.empty()) return;
const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
OS << "Frame Objects:\n";
for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
const StackObject &SO = Objects[i];
OS << " fi#" << (int)(i-NumFixedObjects) << ": ";
if (SO.Size == ~0ULL) {
OS << "dead\n";
continue;
}
if (SO.Size == 0)
OS << "variable sized";
else
OS << "size=" << SO.Size;
OS << ", align=" << SO.Alignment;
if (i < NumFixedObjects)
OS << ", fixed";
if (i < NumFixedObjects || SO.SPOffset != -1) {
int64_t Off = SO.SPOffset - ValOffset;
OS << ", at location [SP";
if (Off > 0)
OS << "+" << Off;
else if (Off < 0)
OS << Off;
OS << "]";
}
OS << "\n";
}
}
void MachineFrameInfo::dump(const MachineFunction &MF) const {
print(MF, dbgs());
}
//===----------------------------------------------------------------------===//
// MachineJumpTableInfo implementation
//===----------------------------------------------------------------------===//
/// getEntrySize - Return the size of each entry in the jump table.
unsigned MachineJumpTableInfo::getEntrySize(const TargetData &TD) const {
// The size of a jump table entry is 4 bytes unless the entry is just the
// address of a block, in which case it is the pointer size.
switch (getEntryKind()) {
case MachineJumpTableInfo::EK_BlockAddress:
return TD.getPointerSize();
case MachineJumpTableInfo::EK_GPRel64BlockAddress:
return 8;
case MachineJumpTableInfo::EK_GPRel32BlockAddress:
case MachineJumpTableInfo::EK_LabelDifference32:
case MachineJumpTableInfo::EK_Custom32:
return 4;
case MachineJumpTableInfo::EK_Inline:
return 0;
}
llvm_unreachable("Unknown jump table encoding!");
}
/// getEntryAlignment - Return the alignment of each entry in the jump table.
unsigned MachineJumpTableInfo::getEntryAlignment(const TargetData &TD) const {
// The alignment of a jump table entry is the alignment of int32 unless the
// entry is just the address of a block, in which case it is the pointer
// alignment.
switch (getEntryKind()) {
case MachineJumpTableInfo::EK_BlockAddress:
return TD.getPointerABIAlignment();
case MachineJumpTableInfo::EK_GPRel64BlockAddress:
return TD.getABIIntegerTypeAlignment(64);
case MachineJumpTableInfo::EK_GPRel32BlockAddress:
case MachineJumpTableInfo::EK_LabelDifference32:
case MachineJumpTableInfo::EK_Custom32:
return TD.getABIIntegerTypeAlignment(32);
case MachineJumpTableInfo::EK_Inline:
return 1;
}
llvm_unreachable("Unknown jump table encoding!");
}
/// createJumpTableIndex - Create a new jump table entry in the jump table info.
///
unsigned MachineJumpTableInfo::createJumpTableIndex(
const std::vector<MachineBasicBlock*> &DestBBs) {
assert(!DestBBs.empty() && "Cannot create an empty jump table!");
JumpTables.push_back(MachineJumpTableEntry(DestBBs));
return JumpTables.size()-1;
}
/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
/// the jump tables to branch to New instead.
bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
MachineBasicBlock *New) {
assert(Old != New && "Not making a change?");
bool MadeChange = false;
for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
ReplaceMBBInJumpTable(i, Old, New);
return MadeChange;
}
/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
/// the jump table to branch to New instead.
bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
MachineBasicBlock *Old,
MachineBasicBlock *New) {
assert(Old != New && "Not making a change?");
bool MadeChange = false;
MachineJumpTableEntry &JTE = JumpTables[Idx];
for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
if (JTE.MBBs[j] == Old) {
JTE.MBBs[j] = New;
MadeChange = true;
}
return MadeChange;
}
void MachineJumpTableInfo::print(raw_ostream &OS) const {
if (JumpTables.empty()) return;
OS << "Jump Tables:\n";
for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
OS << " jt#" << i << ": ";
for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
}
OS << '\n';
}
void MachineJumpTableInfo::dump() const { print(dbgs()); }
//===----------------------------------------------------------------------===//
// MachineConstantPool implementation
//===----------------------------------------------------------------------===//
void MachineConstantPoolValue::anchor() { }
Type *MachineConstantPoolEntry::getType() const {
if (isMachineConstantPoolEntry())
return Val.MachineCPVal->getType();
return Val.ConstVal->getType();
}
unsigned MachineConstantPoolEntry::getRelocationInfo() const {
if (isMachineConstantPoolEntry())
return Val.MachineCPVal->getRelocationInfo();
return Val.ConstVal->getRelocationInfo();
}
MachineConstantPool::~MachineConstantPool() {
for (unsigned i = 0, e = Constants.size(); i != e; ++i)
if (Constants[i].isMachineConstantPoolEntry())
delete Constants[i].Val.MachineCPVal;
for (DenseSet<MachineConstantPoolValue*>::iterator I =
MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
I != E; ++I)
delete *I;
}
/// CanShareConstantPoolEntry - Test whether the given two constants
/// can be allocated the same constant pool entry.
static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
const TargetData *TD) {
// Handle the trivial case quickly.
if (A == B) return true;
// If they have the same type but weren't the same constant, quickly
// reject them.
if (A->getType() == B->getType()) return false;
// We can't handle structs or arrays.
if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
return false;
// For now, only support constants with the same size.
uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
StoreSize > 128)
return false;
Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
// Try constant folding a bitcast of both instructions to an integer. If we
// get two identical ConstantInt's, then we are good to share them. We use
// the constant folding APIs to do this so that we get the benefit of
// TargetData.
if (isa<PointerType>(A->getType()))
A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
const_cast<Constant*>(A), TD);
else if (A->getType() != IntTy)
A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
const_cast<Constant*>(A), TD);
if (isa<PointerType>(B->getType()))
B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
const_cast<Constant*>(B), TD);
else if (B->getType() != IntTy)
B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
const_cast<Constant*>(B), TD);
return A == B;
}
/// getConstantPoolIndex - Create a new entry in the constant pool or return
/// an existing one. User must specify the log2 of the minimum required
/// alignment for the object.
///
unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
unsigned Alignment) {
assert(Alignment && "Alignment must be specified!");
if (Alignment > PoolAlignment) PoolAlignment = Alignment;
// Check to see if we already have this constant.
//
// FIXME, this could be made much more efficient for large constant pools.
for (unsigned i = 0, e = Constants.size(); i != e; ++i)
if (!Constants[i].isMachineConstantPoolEntry() &&
CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
if ((unsigned)Constants[i].getAlignment() < Alignment)
Constants[i].Alignment = Alignment;
return i;
}
Constants.push_back(MachineConstantPoolEntry(C, Alignment));
return Constants.size()-1;
}
unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
unsigned Alignment) {
assert(Alignment && "Alignment must be specified!");
if (Alignment > PoolAlignment) PoolAlignment = Alignment;
// Check to see if we already have this constant.
//
// FIXME, this could be made much more efficient for large constant pools.
int Idx = V->getExistingMachineCPValue(this, Alignment);
if (Idx != -1) {
MachineCPVsSharingEntries.insert(V);
return (unsigned)Idx;
}
Constants.push_back(MachineConstantPoolEntry(V, Alignment));
return Constants.size()-1;
}
void MachineConstantPool::print(raw_ostream &OS) const {
if (Constants.empty()) return;
OS << "Constant Pool:\n";
for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
OS << " cp#" << i << ": ";
if (Constants[i].isMachineConstantPoolEntry())
Constants[i].Val.MachineCPVal->print(OS);
else
OS << *(Value*)Constants[i].Val.ConstVal;
OS << ", align=" << Constants[i].getAlignment();
OS << "\n";
}
}
void MachineConstantPool::dump() const { print(dbgs()); }
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