llvm/lib/CodeGen/MachineFunction.cpp

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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/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Config/config.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
struct Printer : public MachineFunctionPass {
static char ID;
raw_ostream &OS;
const std::string Banner;
Printer(raw_ostream &os, const std::string &banner)
: MachineFunctionPass(&ID), OS(os), Banner(banner) {}
const char *getPassName() const { return "MachineFunction Printer"; }
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool runOnMachineFunction(MachineFunction &MF) {
OS << "# " << Banner << ":\n";
MF.print(OS);
return false;
}
};
char Printer::ID = 0;
}
/// Returns a newly-created MachineFunction Printer pass. The default banner is
/// empty.
///
FunctionPass *llvm::createMachineFunctionPrinterPass(raw_ostream &OS,
const std::string &Banner){
return new Printer(OS, Banner);
}
//===---------------------------------------------------------------------===//
// MachineFunction implementation
//===---------------------------------------------------------------------===//
// Out of line virtual method.
MachineFunctionInfo::~MachineFunctionInfo() {}
void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
MBB->getParent()->DeleteMachineBasicBlock(MBB);
}
MachineFunction::MachineFunction(Function *F,
const TargetMachine &TM)
: Fn(F), Target(TM) {
if (TM.getRegisterInfo())
RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
MachineRegisterInfo(*TM.getRegisterInfo());
else
RegInfo = 0;
MFInfo = 0;
FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
MachineFrameInfo(*TM.getFrameInfo());
ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
MachineConstantPool(TM.getTargetData());
Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
// Set up jump table.
const TargetData &TD = *TM.getTargetData();
bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
unsigned TyAlignment = IsPic ?
TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
: TD.getPointerABIAlignment();
JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
MachineJumpTableInfo(EntrySize, TyAlignment);
}
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);
JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(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 TargetInstrDesc &TID,
DebugLoc DL, bool NoImp) {
return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
MachineInstr(TID, DL, NoImp);
}
/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
/// 'Orig' instruction, identical in all ways except the 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(const Value *v, unsigned f,
int64_t o, uint64_t s,
unsigned base_alignment) {
return new (Allocator.Allocate<MachineMemOperand>())
MachineMemOperand(v, f, o, s, base_alignment);
}
MachineMemOperand *
MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
int64_t Offset, uint64_t Size) {
return new (Allocator.Allocate<MachineMemOperand>())
MachineMemOperand(MMO->getValue(), MMO->getFlags(),
int64_t(uint64_t(MMO->getOffset()) +
uint64_t(Offset)),
Size, MMO->getBaseAlignment());
}
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)->getValue(),
(*I)->getFlags() & ~MachineMemOperand::MOStore,
(*I)->getOffset(), (*I)->getSize(),
(*I)->getBaseAlignment());
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)->getValue(),
(*I)->getFlags() & ~MachineMemOperand::MOLoad,
(*I)->getOffset(), (*I)->getSize(),
(*I)->getBaseAlignment());
Result[Index] = JustStore;
}
++Index;
}
}
return std::make_pair(Result, Result + Num);
}
void MachineFunction::dump() const {
print(errs());
}
void MachineFunction::print(raw_ostream &OS) const {
OS << "# Machine code for function " << Fn->getName() << ":\n";
// Print Frame Information
FrameInfo->print(*this, OS);
// Print JumpTable Information
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) {
if (TRI)
OS << "%" << TRI->getName(I->first);
else
OS << " %physreg" << I->first;
if (I->second)
OS << " in reg%" << I->second;
if (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){
if (TRI)
OS << '%' << TRI->getName(*I);
else
OS << "%physreg" << *I;
if (next(I) != E)
OS << " ";
}
OS << '\n';
}
for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
OS << '\n';
BB->print(OS);
}
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()->getNameStr() + "' function";
}
static std::string getNodeLabel(const MachineBasicBlock *Node,
const MachineFunction *Graph,
bool ShortNames) {
if (ShortNames && Node->getBasicBlock() &&
!Node->getBasicBlock()->getName().empty())
return Node->getBasicBlock()->getNameStr() + ":";
std::string OutStr;
{
raw_string_ostream OSS(OutStr);
if (ShortNames)
OSS << Node->getNumber() << ':';
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()->getNameStr());
#else
errs() << "SelectionDAG::viewGraph 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()->getNameStr(), true);
#else
errs() << "SelectionDAG::viewGraph 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) {
assert(RC->contains(PReg) && "Not the correct regclass!");
unsigned VReg = getRegInfo().createVirtualRegister(RC);
getRegInfo().addLiveIn(PReg, VReg);
return VReg;
}
/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
unsigned Idx = DL.getIndex();
assert(Idx < DebugLocInfo.DebugLocations.size() &&
"Invalid index into debug locations!");
return DebugLocInfo.DebugLocations[Idx];
}
//===----------------------------------------------------------------------===//
// 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, bool isSS) {
assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable,
isSS));
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 unsigned *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 TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
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, errs());
}
//===----------------------------------------------------------------------===//
// MachineJumpTableInfo implementation
//===----------------------------------------------------------------------===//
/// getJumpTableIndex - Create a new jump table entry in the jump table info
/// or return an existing one.
///
unsigned MachineJumpTableInfo::getJumpTableIndex(
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(errs()); }
//===----------------------------------------------------------------------===//
// MachineConstantPool implementation
//===----------------------------------------------------------------------===//
const 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;
}
/// CanShareConstantPoolEntry - Test whether the given two constants
/// can be allocated the same constant pool entry.
static bool CanShareConstantPoolEntry(Constant *A, 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;
// For now, only support constants with the same size.
if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
return false;
// If a floating-point value and an integer value have the same encoding,
// they can share a constant-pool entry.
if (ConstantFP *AFP = dyn_cast<ConstantFP>(A))
if (ConstantInt *BI = dyn_cast<ConstantInt>(B))
return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
if (ConstantFP *BFP = dyn_cast<ConstantFP>(B))
if (ConstantInt *AI = dyn_cast<ConstantInt>(A))
return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
// Two vectors can share an entry if each pair of corresponding
// elements could.
if (ConstantVector *AV = dyn_cast<ConstantVector>(A))
if (ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
return false;
for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
if (!CanShareConstantPoolEntry(AV->getOperand(i),
BV->getOperand(i), TD))
return false;
return true;
}
// TODO: Handle other cases.
return false;
}
/// 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(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;
}
Fix some significant problems with constant pools that resulted in unnecessary paddings between constant pool entries, larger than necessary alignments (e.g. 8 byte alignment for .literal4 sections), and potentially other issues. 1. ConstantPoolSDNode alignment field is log2 value of the alignment requirement. This is not consistent with other SDNode variants. 2. MachineConstantPool alignment field is also a log2 value. 3. However, some places are creating ConstantPoolSDNode with alignment value rather than log2 values. This creates entries with artificially large alignments, e.g. 256 for SSE vector values. 4. Constant pool entry offsets are computed when they are created. However, asm printer group them by sections. That means the offsets are no longer valid. However, asm printer uses them to determine size of padding between entries. 5. Asm printer uses expensive data structure multimap to track constant pool entries by sections. 6. Asm printer iterate over SmallPtrSet when it's emitting constant pool entries. This is non-deterministic. Solutions: 1. ConstantPoolSDNode alignment field is changed to keep non-log2 value. 2. MachineConstantPool alignment field is also changed to keep non-log2 value. 3. Functions that create ConstantPool nodes are passing in non-log2 alignments. 4. MachineConstantPoolEntry no longer keeps an offset field. It's replaced with an alignment field. Offsets are not computed when constant pool entries are created. They are computed on the fly in asm printer and JIT. 5. Asm printer uses cheaper data structure to group constant pool entries. 6. Asm printer compute entry offsets after grouping is done. 7. Change JIT code to compute entry offsets on the fly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66875 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-13 07:51:59 +00:00
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)
return (unsigned)Idx;
Fix some significant problems with constant pools that resulted in unnecessary paddings between constant pool entries, larger than necessary alignments (e.g. 8 byte alignment for .literal4 sections), and potentially other issues. 1. ConstantPoolSDNode alignment field is log2 value of the alignment requirement. This is not consistent with other SDNode variants. 2. MachineConstantPool alignment field is also a log2 value. 3. However, some places are creating ConstantPoolSDNode with alignment value rather than log2 values. This creates entries with artificially large alignments, e.g. 256 for SSE vector values. 4. Constant pool entry offsets are computed when they are created. However, asm printer group them by sections. That means the offsets are no longer valid. However, asm printer uses them to determine size of padding between entries. 5. Asm printer uses expensive data structure multimap to track constant pool entries by sections. 6. Asm printer iterate over SmallPtrSet when it's emitting constant pool entries. This is non-deterministic. Solutions: 1. ConstantPoolSDNode alignment field is changed to keep non-log2 value. 2. MachineConstantPool alignment field is also changed to keep non-log2 value. 3. Functions that create ConstantPool nodes are passing in non-log2 alignments. 4. MachineConstantPoolEntry no longer keeps an offset field. It's replaced with an alignment field. Offsets are not computed when constant pool entries are created. They are computed on the fly in asm printer and JIT. 5. Asm printer uses cheaper data structure to group constant pool entries. 6. Asm printer compute entry offsets after grouping is done. 7. Change JIT code to compute entry offsets on the fly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66875 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-13 07:51:59 +00:00
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(errs()); }