/// GetExceptionObject - Return the exception object from the value passed into
/// the 'resume' instruction (typically an aggregate). Clean up any dead
/// instructions, including the 'resume' instruction.
Value *DwarfEHPrepare::GetExceptionObject(ResumeInst *RI) {
Value *V = RI->getOperand(0);
Value *ExnObj = nullptr;
InsertValueInst *SelIVI = dyn_cast<InsertValueInst>(V);
LoadInst *SelLoad = nullptr;
InsertValueInst *ExcIVI = nullptr;
bool EraseIVIs = false;
if (SelIVI) {
if (SelIVI->getNumIndices() == 1 && *SelIVI->idx_begin() == 1) {
ExcIVI = dyn_cast<InsertValueInst>(SelIVI->getOperand(0));
if (ExcIVI && isa<UndefValue>(ExcIVI->getOperand(0)) &&
ExcIVI->getNumIndices() == 1 && *ExcIVI->idx_begin() == 0) {
ExnObj = ExcIVI->getOperand(1);
SelLoad = dyn_cast<LoadInst>(SelIVI->getOperand(1));
EraseIVIs = true;
}
}
}
if (!ExnObj)
ExnObj = ExtractValueInst::Create(RI->getOperand(0), 0, "exn.obj", RI);
RI->eraseFromParent();
if (EraseIVIs) {
if (SelIVI->use_empty())
SelIVI->eraseFromParent();
if (ExcIVI->use_empty())
ExcIVI->eraseFromParent();
if (SelLoad && SelLoad->use_empty())
SelLoad->eraseFromParent();
}
return ExnObj;
}
/// PromoteAliasSet - Try to promote memory values to scalars by sinking
/// stores out of the loop and moving loads to before the loop. We do this by
/// looping over the stores in the loop, looking for stores to Must pointers
/// which are loop invariant.
///
void LICM::PromoteAliasSet(AliasSet &AS) {
// We can promote this alias set if it has a store, if it is a "Must" alias
// set, if the pointer is loop invariant, and if we are not eliminating any
// volatile loads or stores.
if (AS.isForwardingAliasSet() || !AS.isMod() || !AS.isMustAlias() ||
AS.isVolatile() || !CurLoop->isLoopInvariant(AS.begin()->getValue()))
return;
assert(!AS.empty() &&
"Must alias set should have at least one pointer element in it!");
Value *SomePtr = AS.begin()->getValue();
// It isn't safe to promote a load/store from the loop if the load/store is
// conditional. For example, turning:
//
// for () { if (c) *P += 1; }
//
// into:
//
// tmp = *P; for () { if (c) tmp +=1; } *P = tmp;
//
// is not safe, because *P may only be valid to access if 'c' is true.
//
// It is safe to promote P if all uses are direct load/stores and if at
// least one is guaranteed to be executed.
bool GuaranteedToExecute = false;
SmallVector<Instruction*, 64> LoopUses;
SmallPtrSet<Value*, 4> PointerMustAliases;
// We start with an alignment of one and try to find instructions that allow
// us to prove better alignment.
unsigned Alignment = 1;
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) {
Value *ASIV = ASI->getValue();
PointerMustAliases.insert(ASIV);
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
if (SomePtr->getType() != ASIV->getType())
return;
for (Value::use_iterator UI = ASIV->use_begin(), UE = ASIV->use_end();
UI != UE; ++UI) {
// Ignore instructions that are outside the loop.
Instruction *Use = dyn_cast<Instruction>(*UI);
if (!Use || !CurLoop->contains(Use))
continue;
// If there is an non-load/store instruction in the loop, we can't promote
// it.
if (LoadInst *load = dyn_cast<LoadInst>(Use)) {
assert(!load->isVolatile() && "AST broken");
if (!load->isSimple())
return;
} else if (StoreInst *store = dyn_cast<StoreInst>(Use)) {
// Stores *of* the pointer are not interesting, only stores *to* the
// pointer.
if (Use->getOperand(1) != ASIV)
continue;
assert(!store->isVolatile() && "AST broken");
if (!store->isSimple())
return;
// Note that we only check GuaranteedToExecute inside the store case
// so that we do not introduce stores where they did not exist before
// (which would break the LLVM concurrency model).
// If the alignment of this instruction allows us to specify a more
// restrictive (and performant) alignment and if we are sure this
// instruction will be executed, update the alignment.
// Larger is better, with the exception of 0 being the best alignment.
unsigned InstAlignment = store->getAlignment();
if ((InstAlignment > Alignment || InstAlignment == 0)
&& (Alignment != 0))
if (isGuaranteedToExecute(*Use)) {
GuaranteedToExecute = true;
Alignment = InstAlignment;
}
if (!GuaranteedToExecute)
GuaranteedToExecute = isGuaranteedToExecute(*Use);
} else
return; // Not a load or store.
LoopUses.push_back(Use);
}
}
// If there isn't a guaranteed-to-execute instruction, we can't promote.
if (!GuaranteedToExecute)
return;
// Otherwise, this is safe to promote, lets do it!
DEBUG(dbgs() << "LICM: Promoting value stored to in loop: " <<*SomePtr<<'\n');
Changed = true;
++NumPromoted;
// Grab a debug location for the inserted loads/stores; given that the
// inserted loads/stores have little relation to the original loads/stores,
// this code just arbitrarily picks a location from one, since any debug
// location is better than none.
DebugLoc DL = LoopUses[0]->getDebugLoc();
SmallVector<BasicBlock*, 8> ExitBlocks;
CurLoop->getUniqueExitBlocks(ExitBlocks);
// We use the SSAUpdater interface to insert phi nodes as required.
SmallVector<PHINode*, 16> NewPHIs;
SSAUpdater SSA(&NewPHIs);
LoopPromoter Promoter(SomePtr, LoopUses, SSA, PointerMustAliases, ExitBlocks,
*CurAST, DL, Alignment);
// Set up the preheader to have a definition of the value. It is the live-out
// value from the preheader that uses in the loop will use.
LoadInst *PreheaderLoad =
new LoadInst(SomePtr, SomePtr->getName()+".promoted",
Preheader->getTerminator());
PreheaderLoad->setAlignment(Alignment);
PreheaderLoad->setDebugLoc(DL);
SSA.AddAvailableValue(Preheader, PreheaderLoad);
// Rewrite all the loads in the loop and remember all the definitions from
// stores in the loop.
Promoter.run(LoopUses);
// If the SSAUpdater didn't use the load in the preheader, just zap it now.
if (PreheaderLoad->use_empty())
PreheaderLoad->eraseFromParent();
}
/// Attempt to merge an objc_release with a store, load, and objc_retain to form
/// an objc_storeStrong. This can be a little tricky because the instructions
/// don't always appear in order, and there may be unrelated intervening
/// instructions.
void ObjCARCContract::ContractRelease(Instruction *Release,
inst_iterator &Iter) {
LoadInst *Load = dyn_cast<LoadInst>(GetObjCArg(Release));
if (!Load || !Load->isSimple()) return;
// For now, require everything to be in one basic block.
BasicBlock *BB = Release->getParent();
if (Load->getParent() != BB) return;
// Walk down to find the store and the release, which may be in either order.
BasicBlock::iterator I = Load, End = BB->end();
++I;
AliasAnalysis::Location Loc = AA->getLocation(Load);
StoreInst *Store = 0;
bool SawRelease = false;
for (; !Store || !SawRelease; ++I) {
if (I == End)
return;
Instruction *Inst = I;
if (Inst == Release) {
SawRelease = true;
continue;
}
InstructionClass Class = GetBasicInstructionClass(Inst);
// Unrelated retains are harmless.
if (IsRetain(Class))
continue;
if (Store) {
// The store is the point where we're going to put the objc_storeStrong,
// so make sure there are no uses after it.
if (CanUse(Inst, Load, PA, Class))
return;
} else if (AA->getModRefInfo(Inst, Loc) & AliasAnalysis::Mod) {
// We are moving the load down to the store, so check for anything
// else which writes to the memory between the load and the store.
Store = dyn_cast<StoreInst>(Inst);
if (!Store || !Store->isSimple()) return;
if (Store->getPointerOperand() != Loc.Ptr) return;
}
}
Value *New = StripPointerCastsAndObjCCalls(Store->getValueOperand());
// Walk up to find the retain.
I = Store;
BasicBlock::iterator Begin = BB->begin();
while (I != Begin && GetBasicInstructionClass(I) != IC_Retain)
--I;
Instruction *Retain = I;
if (GetBasicInstructionClass(Retain) != IC_Retain) return;
if (GetObjCArg(Retain) != New) return;
Changed = true;
++NumStoreStrongs;
LLVMContext &C = Release->getContext();
Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
Type *I8XX = PointerType::getUnqual(I8X);
Value *Args[] = { Load->getPointerOperand(), New };
if (Args[0]->getType() != I8XX)
Args[0] = new BitCastInst(Args[0], I8XX, "", Store);
if (Args[1]->getType() != I8X)
Args[1] = new BitCastInst(Args[1], I8X, "", Store);
CallInst *StoreStrong =
CallInst::Create(getStoreStrongCallee(BB->getParent()->getParent()),
Args, "", Store);
StoreStrong->setDoesNotThrow();
StoreStrong->setDebugLoc(Store->getDebugLoc());
// We can't set the tail flag yet, because we haven't yet determined
// whether there are any escaping allocas. Remember this call, so that
// we can set the tail flag once we know it's safe.
StoreStrongCalls.insert(StoreStrong);
if (&*Iter == Store) ++Iter;
Store->eraseFromParent();
Release->eraseFromParent();
EraseInstruction(Retain);
if (Load->use_empty())
Load->eraseFromParent();
}
Function * futamurize( const Function * orig_func, DenseMap<const Value*, Value*> &argmap, std::set<const unsigned char *> &constant_addresses_set )
{
LLVMContext &context = getGlobalContext();
// Make a copy of the function, removing constant arguments
Function * specialized_func = CloneFunction( orig_func, argmap );
specialized_func->setName( orig_func->getNameStr() + "_1" );
// add it to our module
LLVM_Module->getFunctionList().push_back( specialized_func );
printf("\nspecialized_func = %p <%s>\n", specialized_func, specialized_func->getName().data());
//~ specialized_func->dump();
// Optimize it
FunctionPassManager PM( LLVM_Module );
createStandardFunctionPasses( &PM, 3 );
PM.add(createScalarReplAggregatesPass()); // Break up aggregate allocas
PM.add(createInstructionCombiningPass()); // Cleanup for scalarrepl.
PM.add(createJumpThreadingPass()); // Thread jumps.
PM.add(createCFGSimplificationPass()); // Merge & remove BBs
PM.add(createInstructionCombiningPass()); // Combine silly seq's
PM.add(createTailCallEliminationPass()); // Eliminate tail calls
PM.add(createCFGSimplificationPass()); // Merge & remove BBs
PM.add(createReassociatePass()); // Reassociate expressions
PM.add(createLoopRotatePass()); // Rotate Loop
PM.add(createLICMPass()); // Hoist loop invariants
PM.add(createLoopUnswitchPass( false ));
PM.add(createInstructionCombiningPass());
PM.add(createIndVarSimplifyPass()); // Canonicalize indvars
PM.add(createLoopDeletionPass()); // Delete dead loops
PM.add(createLoopUnroll2Pass()); // Unroll small loops
PM.add(createInstructionCombiningPass()); // Clean up after the unroller
PM.add(createGVNPass()); // Remove redundancies
PM.add(createMemCpyOptPass()); // Remove memcpy / form memset
PM.add(createSCCPPass()); // Constant prop with SCCP
PM.add(createPromoteMemoryToRegisterPass());
PM.add(createConstantPropagationPass());
PM.add(createDeadStoreEliminationPass());
PM.add(createAggressiveDCEPass());
PM.add(new MemoryDependenceAnalysis());
//~ PM.add(createAAEvalPass());
const PassInfo * pinfo = Pass::lookupPassInfo( "print-alias-sets" );
if( !pinfo ) { printf( "print-alias-sets not found\n" ); exit(-1); }
PM.add( pinfo->createPass() );
FunctionPassManager PM_Inline( LLVM_Module );
PM_Inline.add(createSingleFunctionInliningPass());
bool Changed = false;
int iterations = 2;
int inline_iterations = 6;
do
{
Changed = false;
// first do some optimizations
PM.doInitialization();
PM.run( *specialized_func );
PM.doFinalization();
// Load from Constant Memory detection
const TargetData *TD = LLVM_EE->getTargetData();
for (inst_iterator I = inst_begin(specialized_func), E = inst_end(specialized_func); I != E; ++I)
{
Instruction * inst = (Instruction *) &*I;
// get all Load instructions
LoadInst * load = dyn_cast<LoadInst>( inst );
if( !load ) continue;
if( load->isVolatile() ) continue;
if (load->use_empty()) continue; // Don't muck with dead instructions...
// get the address loaded by load instruction
Value *ptr_value = load->getPointerOperand();
// we're only interested in constant addresses
ConstantExpr * ptr_constant_expr = dyn_cast<ConstantExpr>( ptr_value );
if( !ptr_constant_expr ) continue;
ptr_constant_expr->dump();
// compute real address of constant pointer expression
Constant * ptr_constant = ConstantFoldConstantExpression( ptr_constant_expr, TD );
if( !ptr_constant ) continue;
ptr_constant->dump();
// convert to int constant
ConstantInt *int_constant = dyn_cast<ConstantInt>( ConstantExpr::getPtrToInt( ptr_constant, Type::getInt64Ty( context )));
if( !int_constant ) continue;
int_constant->dump();
// get data size
int data_length = TD->getTypeAllocSize( load->getType() );
ptr_value->getType()->dump();
// get real address (at last !)
const unsigned char * c_ptr = (const unsigned char *) int_constant->getLimitedValue();
printf( "%ld %d %d\n", c_ptr, constant_addresses_set.count( c_ptr ), data_length );
// check what's in this address
int isconst = 1;
for( int offset=0; offset<data_length; offset++ )
isconst &= constant_addresses_set.count( c_ptr + offset );
if( !isconst ) continue;
printf( "It is constant.\n" );
// make a LLVM const with the data
Constant *new_constant = NULL;
switch( data_length )
{
case 1: new_constant = ConstantInt::get( Type::getInt8Ty( context ), *(uint8_t*)c_ptr, false /* signed */ ); break;
case 2: new_constant = ConstantInt::get( Type::getInt16Ty( context ), *(uint16_t*)c_ptr, false /* signed */ ); break;
case 4: new_constant = ConstantInt::get( Type::getInt32Ty( context ), *(uint32_t*)c_ptr, false /* signed */ ); break;
case 8: new_constant = ConstantInt::get( Type::getInt64Ty( context ), *(uint64_t*)c_ptr, false /* signed */ ); break;
default:
{
StringRef const_data ( (const char *) c_ptr, data_length );
new_constant = ConstantArray::get( context, const_data, false /* dont add terminating null */ );
}
}
if( !new_constant ) continue;
new_constant->dump();
//~ // get the type that is loaded
const Type *Ty = load->getType();
// do we need a cast ?
if( load->getType() != new_constant->getType() )
{
new_constant = ConstantExpr::getBitCast( new_constant, Ty );
new_constant->dump();
}
// zap the load and replace with constant address
load->replaceAllUsesWith( new_constant );
printf( "\nREPLACED :...\n" );
load->dump();
new_constant->dump();
Changed = true;
}
if( Changed )
continue; // re-optimize and do another pass of constant load elimination
// if we can't do anything else, do an inlining pass
if( inline_iterations > 0 )
{
inline_iterations --;
PM_Inline.doInitialization();
Changed |= PM_Inline.run( *specialized_func );
PM_Inline.doFinalization();
//~ for( int i=0; i<3; i++ )
{
PM.doInitialization();
Changed |= PM.run( *specialized_func );
PM.doFinalization();
}
}
if( iterations>0 && !Changed )
iterations--;
} while( Changed || iterations>0 );
return specialized_func;
}