#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
+#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
return F == O.F && Idx == O.Idx && IsArg == O.IsArg;
}
- std::string getDescription() {
+ std::string getDescription() const {
return std::string((IsArg ? "Argument #" : "Return value #"))
- + utostr(Idx) + " of function " + F->getName();
+ + utostr(Idx) + " of function " + F->getNameStr();
}
};
UseMap Uses;
typedef std::set<RetOrArg> LiveSet;
+ typedef std::set<const Function*> LiveFuncSet;
/// This set contains all values that have been determined to be live.
LiveSet LiveValues;
+ /// This set contains all values that are cannot be changed in any way.
+ LiveFuncSet LiveFunctions;
typedef SmallVector<RetOrArg, 5> UseVector;
public:
static char ID; // Pass identification, replacement for typeid
- DAE() : ModulePass((intptr_t)&ID) {}
+ DAE() : ModulePass(&ID) {}
bool runOnModule(Module &M);
virtual bool ShouldHackArguments() const { return false; }
void SurveyFunction(Function &F);
void MarkValue(const RetOrArg &RA, Liveness L,
const UseVector &MaybeLiveUses);
- void MarkLive(RetOrArg RA);
+ void MarkLive(const RetOrArg &RA);
void MarkLive(const Function &F);
+ void PropagateLiveness(const RetOrArg &RA);
bool RemoveDeadStuffFromFunction(Function *F);
bool DeleteDeadVarargs(Function &Fn);
};
/// llvm.vastart is never called, the varargs list is dead for the function.
bool DAE::DeleteDeadVarargs(Function &Fn) {
assert(Fn.getFunctionType()->isVarArg() && "Function isn't varargs!");
- if (Fn.isDeclaration() || !Fn.hasInternalLinkage()) return false;
+ if (Fn.isDeclaration() || !Fn.hasLocalLinkage()) return false;
// Ensure that the function is only directly called.
- for (Value::use_iterator I = Fn.use_begin(), E = Fn.use_end(); I != E; ++I) {
- // If this use is anything other than a call site, give up.
- CallSite CS = CallSite::get(*I);
- Instruction *TheCall = CS.getInstruction();
- if (!TheCall) return false; // Not a direct call site?
-
- // The addr of this function is passed to the call.
- if (I.getOperandNo() != 0) return false;
- }
+ if (Fn.hasAddressTaken())
+ return false;
// Okay, we know we can transform this function if safe. Scan its body
// looking for calls to llvm.vastart.
// Start by computing a new prototype for the function, which is the same as
// the old function, but doesn't have isVarArg set.
const FunctionType *FTy = Fn.getFunctionType();
+
std::vector<const Type*> Params(FTy->param_begin(), FTy->param_end());
- FunctionType *NFTy = FunctionType::get(FTy->getReturnType(), Params, false);
+ FunctionType *NFTy = FunctionType::get(FTy->getReturnType(),
+ Params, false);
unsigned NumArgs = Params.size();
// Create the new function body and insert it into the module...
Args.assign(CS.arg_begin(), CS.arg_begin()+NumArgs);
// Drop any attributes that were on the vararg arguments.
- PAListPtr PAL = CS.getParamAttrs();
+ AttrListPtr PAL = CS.getAttributes();
if (!PAL.isEmpty() && PAL.getSlot(PAL.getNumSlots() - 1).Index > NumArgs) {
- SmallVector<ParamAttrsWithIndex, 8> ParamAttrsVec;
+ SmallVector<AttributeWithIndex, 8> AttributesVec;
for (unsigned i = 0; PAL.getSlot(i).Index <= NumArgs; ++i)
- ParamAttrsVec.push_back(PAL.getSlot(i));
- PAL = PAListPtr::get(ParamAttrsVec.begin(), ParamAttrsVec.end());
+ AttributesVec.push_back(PAL.getSlot(i));
+ if (Attributes FnAttrs = PAL.getFnAttributes())
+ AttributesVec.push_back(AttributeWithIndex::get(~0, FnAttrs));
+ PAL = AttrListPtr::get(AttributesVec.begin(), AttributesVec.end());
}
Instruction *New;
New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(),
Args.begin(), Args.end(), "", Call);
cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv());
- cast<InvokeInst>(New)->setParamAttrs(PAL);
+ cast<InvokeInst>(New)->setAttributes(PAL);
} else {
New = CallInst::Create(NF, Args.begin(), Args.end(), "", Call);
cast<CallInst>(New)->setCallingConv(CS.getCallingConv());
- cast<CallInst>(New)->setParamAttrs(PAL);
+ cast<CallInst>(New)->setAttributes(PAL);
if (cast<CallInst>(Call)->isTailCall())
cast<CallInst>(New)->setTailCall();
}
/// for void functions and 1 for functions not returning a struct. It returns
/// the number of struct elements for functions returning a struct.
static unsigned NumRetVals(const Function *F) {
- if (F->getReturnType() == Type::VoidTy)
+ if (F->getReturnType() == Type::getVoidTy(F->getContext()))
return 0;
else if (const StructType *STy = dyn_cast<StructType>(F->getReturnType()))
return STy->getNumElements();
/// live, it adds Use to the MaybeLiveUses argument. Returns the determined
/// liveness of Use.
DAE::Liveness DAE::MarkIfNotLive(RetOrArg Use, UseVector &MaybeLiveUses) {
- // We're live if our use is already marked as live.
- if (LiveValues.count(Use))
+ // We're live if our use or its Function is already marked as live.
+ if (LiveFunctions.count(Use.F) || LiveValues.count(Use))
return Live;
// We're maybe live otherwise, but remember that we must become live if
return;
}
- if (!F.hasInternalLinkage() && (!ShouldHackArguments() || F.isIntrinsic())) {
+ if (!F.hasLocalLinkage() && (!ShouldHackArguments() || F.isIntrinsic())) {
MarkLive(F);
return;
}
- DOUT << "DAE - Inspecting callers for fn: " << F.getName() << "\n";
+ DEBUG(errs() << "DAE - Inspecting callers for fn: " << F.getName() << "\n");
// Keep track of the number of live retvals, so we can skip checks once all
// of them turn out to be live.
unsigned NumLiveRetVals = 0;
for (Value::use_iterator I = F.use_begin(), E = F.use_end(); I != E; ++I) {
// If the function is PASSED IN as an argument, its address has been
// taken.
- if (I.getOperandNo() != 0) {
+ CallSite CS = CallSite::get(*I);
+ if (!CS.getInstruction() || !CS.isCallee(I)) {
MarkLive(F);
return;
}
// If this use is anything other than a call site, the function is alive.
- CallSite CS = CallSite::get(*I);
Instruction *TheCall = CS.getInstruction();
if (!TheCall) { // Not a direct call site?
MarkLive(F);
for (unsigned i = 0; i != RetCount; ++i)
MarkValue(CreateRet(&F, i), RetValLiveness[i], MaybeLiveRetUses[i]);
- DOUT << "DAE - Inspecting args for fn: " << F.getName() << "\n";
+ DEBUG(errs() << "DAE - Inspecting args for fn: " << F.getName() << "\n");
// Now, check all of our arguments.
unsigned i = 0;
/// mark any values that are used as this function's parameters or by its return
/// values (according to Uses) live as well.
void DAE::MarkLive(const Function &F) {
- DOUT << "DAE - Intrinsically live fn: " << F.getName() << "\n";
+ DEBUG(errs() << "DAE - Intrinsically live fn: " << F.getName() << "\n");
+ // Mark the function as live.
+ LiveFunctions.insert(&F);
// Mark all arguments as live.
for (unsigned i = 0, e = F.arg_size(); i != e; ++i)
- MarkLive(CreateArg(&F, i));
+ PropagateLiveness(CreateArg(&F, i));
// Mark all return values as live.
for (unsigned i = 0, e = NumRetVals(&F); i != e; ++i)
- MarkLive(CreateRet(&F, i));
+ PropagateLiveness(CreateRet(&F, i));
}
/// MarkLive - Mark the given return value or argument as live. Additionally,
/// mark any values that are used by this value (according to Uses) live as
/// well.
-void DAE::MarkLive(RetOrArg RA) {
+void DAE::MarkLive(const RetOrArg &RA) {
+ if (LiveFunctions.count(RA.F))
+ return; // Function was already marked Live.
+
if (!LiveValues.insert(RA).second)
return; // We were already marked Live.
- if (RA.IsArg)
- DOUT << "DAE - Marking argument " << RA.Idx << " to function "
- << RA.F->getNameStart() << " live\n";
- else
- DOUT << "DAE - Marking return value " << RA.Idx << " of function "
- << RA.F->getNameStart() << " live\n";
+ DOUT << "DAE - Marking " << RA.getDescription() << " live\n";
+ PropagateLiveness(RA);
+}
+/// PropagateLiveness - Given that RA is a live value, propagate it's liveness
+/// to any other values it uses (according to Uses).
+void DAE::PropagateLiveness(const RetOrArg &RA) {
// We don't use upper_bound (or equal_range) here, because our recursive call
// to ourselves is likely to cause the upper_bound (which is the first value
// not belonging to RA) to become erased and the iterator invalidated.
// the function to not have these arguments and return values.
//
bool DAE::RemoveDeadStuffFromFunction(Function *F) {
- // Quick exit path for external functions
- if (!F->hasInternalLinkage() && (!ShouldHackArguments() || F->isIntrinsic()))
+ // Don't modify fully live functions
+ if (LiveFunctions.count(F))
return false;
// Start by computing a new prototype for the function, which is the same as
std::vector<const Type*> Params;
// Set up to build a new list of parameter attributes.
- SmallVector<ParamAttrsWithIndex, 8> ParamAttrsVec;
- const PAListPtr &PAL = F->getParamAttrs();
+ SmallVector<AttributeWithIndex, 8> AttributesVec;
+ const AttrListPtr &PAL = F->getAttributes();
// The existing function return attributes.
- ParameterAttributes RAttrs = PAL.getParamAttrs(0);
-
+ Attributes RAttrs = PAL.getRetAttributes();
+ Attributes FnAttrs = PAL.getFnAttributes();
// Find out the new return value.
const Type *RetTy = FTy->getReturnType();
const Type *NRetTy = NULL;
unsigned RetCount = NumRetVals(F);
- // Explicitly track if anything changed, for debugging.
- bool Changed = false;
+
// -1 means unused, other numbers are the new index
SmallVector<int, 5> NewRetIdxs(RetCount, -1);
std::vector<const Type*> RetTypes;
- if (RetTy == Type::VoidTy) {
- NRetTy = Type::VoidTy;
+ if (RetTy == Type::getVoidTy(F->getContext())) {
+ NRetTy = Type::getVoidTy(F->getContext());
} else {
const StructType *STy = dyn_cast<StructType>(RetTy);
if (STy)
NewRetIdxs[i] = RetTypes.size() - 1;
} else {
++NumRetValsEliminated;
- DOUT << "DAE - Removing return value " << i << " from "
- << F->getNameStart() << "\n";
- Changed = true;
+ DEBUG(errs() << "DAE - Removing return value " << i << " from "
+ << F->getName() << "\n");
}
}
else
RetTypes.push_back(RetTy);
NewRetIdxs[0] = 0;
} else {
- DOUT << "DAE - Removing return value from " << F->getNameStart()
- << "\n";
+ DEBUG(errs() << "DAE - Removing return value from " << F->getName()
+ << "\n");
++NumRetValsEliminated;
- Changed = true;
}
- if (RetTypes.size() > 1 || (STy && STy->getNumElements()==RetTypes.size()))
+ if (RetTypes.size() > 1)
// More than one return type? Return a struct with them. Also, if we used
// to return a struct and didn't change the number of return values,
// return a struct again. This prevents changing {something} into
// something and {} into void.
// Make the new struct packed if we used to return a packed struct
// already.
- NRetTy = StructType::get(RetTypes, STy->isPacked());
+ NRetTy = StructType::get(STy->getContext(), RetTypes, STy->isPacked());
else if (RetTypes.size() == 1)
// One return type? Just a simple value then, but only if we didn't use to
// return a struct with that simple value before.
NRetTy = RetTypes.front();
else if (RetTypes.size() == 0)
// No return types? Make it void, but only if we didn't use to return {}.
- NRetTy = Type::VoidTy;
+ NRetTy = Type::getVoidTy(F->getContext());
}
assert(NRetTy && "No new return type found?");
// values. Otherwise, ensure that we don't have any conflicting attributes
// here. Currently, this should not be possible, but special handling might be
// required when new return value attributes are added.
- if (NRetTy == Type::VoidTy)
- RAttrs &= ~ParamAttr::typeIncompatible(NRetTy);
+ if (NRetTy == Type::getVoidTy(F->getContext()))
+ RAttrs &= ~Attribute::typeIncompatible(NRetTy);
else
- assert((RAttrs & ParamAttr::typeIncompatible(NRetTy)) == 0
+ assert((RAttrs & Attribute::typeIncompatible(NRetTy)) == 0
&& "Return attributes no longer compatible?");
if (RAttrs)
- ParamAttrsVec.push_back(ParamAttrsWithIndex::get(0, RAttrs));
+ AttributesVec.push_back(AttributeWithIndex::get(0, RAttrs));
// Remember which arguments are still alive.
SmallVector<bool, 10> ArgAlive(FTy->getNumParams(), false);
// Get the original parameter attributes (skipping the first one, that is
// for the return value.
- if (ParameterAttributes Attrs = PAL.getParamAttrs(i + 1))
- ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Params.size(), Attrs));
+ if (Attributes Attrs = PAL.getParamAttributes(i + 1))
+ AttributesVec.push_back(AttributeWithIndex::get(Params.size(), Attrs));
} else {
++NumArgumentsEliminated;
- DOUT << "DAE - Removing argument " << i << " (" << I->getNameStart()
- << ") from " << F->getNameStart() << "\n";
- Changed = true;
+ DEBUG(errs() << "DAE - Removing argument " << i << " (" << I->getName()
+ << ") from " << F->getName() << "\n");
}
}
- // Reconstruct the ParamAttrsList based on the vector we constructed.
- PAListPtr NewPAL = PAListPtr::get(ParamAttrsVec.begin(), ParamAttrsVec.end());
+ if (FnAttrs != Attribute::None)
+ AttributesVec.push_back(AttributeWithIndex::get(~0, FnAttrs));
+
+ // Reconstruct the AttributesList based on the vector we constructed.
+ AttrListPtr NewPAL = AttrListPtr::get(AttributesVec.begin(), AttributesVec.end());
// Work around LLVM bug PR56: the CWriter cannot emit varargs functions which
// have zero fixed arguments.
bool ExtraArgHack = false;
if (Params.empty() && FTy->isVarArg() && FTy->getNumParams() != 0) {
ExtraArgHack = true;
- Params.push_back(Type::Int32Ty);
+ Params.push_back(Type::getInt32Ty(F->getContext()));
}
// Create the new function type based on the recomputed parameters.
- FunctionType *NFTy = FunctionType::get(NRetTy, Params, FTy->isVarArg());
+ FunctionType *NFTy = FunctionType::get(NRetTy, Params,
+ FTy->isVarArg());
// No change?
if (NFTy == FTy)
return false;
- // The function type is only allowed to be different if we actually left out
- // an argument or return value.
- assert(Changed && "Function type changed while no arguments or return values"
- "were removed!");
-
// Create the new function body and insert it into the module...
Function *NF = Function::Create(NFTy, F->getLinkage());
NF->copyAttributesFrom(F);
- NF->setParamAttrs(NewPAL);
+ NF->setAttributes(NewPAL);
// Insert the new function before the old function, so we won't be processing
// it again.
F->getParent()->getFunctionList().insert(F, NF);
CallSite CS = CallSite::get(F->use_back());
Instruction *Call = CS.getInstruction();
- ParamAttrsVec.clear();
- const PAListPtr &CallPAL = CS.getParamAttrs();
+ AttributesVec.clear();
+ const AttrListPtr &CallPAL = CS.getAttributes();
// The call return attributes.
- ParameterAttributes RAttrs = CallPAL.getParamAttrs(0);
+ Attributes RAttrs = CallPAL.getRetAttributes();
+ Attributes FnAttrs = CallPAL.getFnAttributes();
// Adjust in case the function was changed to return void.
- RAttrs &= ~ParamAttr::typeIncompatible(NF->getReturnType());
+ RAttrs &= ~Attribute::typeIncompatible(NF->getReturnType());
if (RAttrs)
- ParamAttrsVec.push_back(ParamAttrsWithIndex::get(0, RAttrs));
+ AttributesVec.push_back(AttributeWithIndex::get(0, RAttrs));
// Declare these outside of the loops, so we can reuse them for the second
// loop, which loops the varargs.
if (ArgAlive[i]) {
Args.push_back(*I);
// Get original parameter attributes, but skip return attributes.
- if (ParameterAttributes Attrs = CallPAL.getParamAttrs(i + 1))
- ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Args.size(), Attrs));
+ if (Attributes Attrs = CallPAL.getParamAttributes(i + 1))
+ AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs));
}
if (ExtraArgHack)
- Args.push_back(UndefValue::get(Type::Int32Ty));
+ Args.push_back(UndefValue::get(Type::getInt32Ty(F->getContext())));
// Push any varargs arguments on the list. Don't forget their attributes.
for (CallSite::arg_iterator E = CS.arg_end(); I != E; ++I, ++i) {
Args.push_back(*I);
- if (ParameterAttributes Attrs = CallPAL.getParamAttrs(i + 1))
- ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Args.size(), Attrs));
+ if (Attributes Attrs = CallPAL.getParamAttributes(i + 1))
+ AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs));
}
- // Reconstruct the ParamAttrsList based on the vector we constructed.
- PAListPtr NewCallPAL = PAListPtr::get(ParamAttrsVec.begin(),
- ParamAttrsVec.end());
+ if (FnAttrs != Attribute::None)
+ AttributesVec.push_back(AttributeWithIndex::get(~0, FnAttrs));
+
+ // Reconstruct the AttributesList based on the vector we constructed.
+ AttrListPtr NewCallPAL = AttrListPtr::get(AttributesVec.begin(),
+ AttributesVec.end());
Instruction *New;
if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(),
Args.begin(), Args.end(), "", Call);
cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv());
- cast<InvokeInst>(New)->setParamAttrs(NewCallPAL);
+ cast<InvokeInst>(New)->setAttributes(NewCallPAL);
} else {
New = CallInst::Create(NF, Args.begin(), Args.end(), "", Call);
cast<CallInst>(New)->setCallingConv(CS.getCallingConv());
- cast<CallInst>(New)->setParamAttrs(NewCallPAL);
+ cast<CallInst>(New)->setAttributes(NewCallPAL);
if (cast<CallInst>(Call)->isTailCall())
cast<CallInst>(New)->setTailCall();
}
// Return type not changed? Just replace users then.
Call->replaceAllUsesWith(New);
New->takeName(Call);
- } else if (New->getType() == Type::VoidTy) {
+ } else if (New->getType() == Type::getVoidTy(F->getContext())) {
// Our return value has uses, but they will get removed later on.
// Replace by null for now.
Call->replaceAllUsesWith(Constant::getNullValue(Call->getType()));
} else {
- assert(isa<StructType>(RetTy) && "Return type changed, but not into a"
- "void. The old return type must have"
- "been a struct!");
- // The original return value was a struct, update all uses (which are
- // all extractvalue instructions).
- for (Value::use_iterator I = Call->use_begin(), E = Call->use_end();
- I != E;) {
- assert(isa<ExtractValueInst>(*I) && "Return value not only used by"
- "extractvalue?");
- ExtractValueInst *EV = cast<ExtractValueInst>(*I);
- // Increment now, since we're about to throw away this use.
- ++I;
- assert(EV->hasIndices() && "Return value used by extractvalue without"
- "indices?");
- unsigned Idx = *EV->idx_begin();
- if (NewRetIdxs[Idx] != -1) {
- if (RetTypes.size() > 1) {
- // We're still returning a struct, create a new extractvalue
- // instruction with the first index updated
- std::vector<unsigned> NewIdxs(EV->idx_begin(), EV->idx_end());
- NewIdxs[0] = NewRetIdxs[Idx];
- Value *NEV = ExtractValueInst::Create(New, NewIdxs.begin(),
- NewIdxs.end(), "retval",
- EV);
- EV->replaceAllUsesWith(NEV);
- EV->eraseFromParent();
- } else {
- // We are now only returning a simple value, remove the
- // extractvalue.
- EV->replaceAllUsesWith(New);
- EV->eraseFromParent();
- }
- } else {
- // Value unused, replace uses by null for now, they will get removed
- // later on.
- EV->replaceAllUsesWith(Constant::getNullValue(EV->getType()));
- EV->eraseFromParent();
- }
+ assert(isa<StructType>(RetTy) &&
+ "Return type changed, but not into a void. The old return type"
+ " must have been a struct!");
+ Instruction *InsertPt = Call;
+ if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
+ BasicBlock::iterator IP = II->getNormalDest()->begin();
+ while (isa<PHINode>(IP)) ++IP;
+ InsertPt = IP;
}
+
+ // We used to return a struct. Instead of doing smart stuff with all the
+ // uses of this struct, we will just rebuild it using
+ // extract/insertvalue chaining and let instcombine clean that up.
+ //
+ // Start out building up our return value from undef
+ Value *RetVal = UndefValue::get(RetTy);
+ for (unsigned i = 0; i != RetCount; ++i)
+ if (NewRetIdxs[i] != -1) {
+ Value *V;
+ if (RetTypes.size() > 1)
+ // We are still returning a struct, so extract the value from our
+ // return value
+ V = ExtractValueInst::Create(New, NewRetIdxs[i], "newret",
+ InsertPt);
+ else
+ // We are now returning a single element, so just insert that
+ V = New;
+ // Insert the value at the old position
+ RetVal = InsertValueInst::Create(RetVal, V, i, "oldret", InsertPt);
+ }
+ // Now, replace all uses of the old call instruction with the return
+ // struct we built
+ Call->replaceAllUsesWith(RetVal);
New->takeName(Call);
}
}
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
Value *RetVal;
- if (NFTy->getReturnType() == Type::VoidTy) {
+ if (NFTy->getReturnType() == Type::getVoidTy(F->getContext())) {
RetVal = 0;
} else {
assert (isa<StructType>(RetTy));
// clean that up.
Value *OldRet = RI->getOperand(0);
// Start out building up our return value from undef
- RetVal = llvm::UndefValue::get(NRetTy);
+ RetVal = UndefValue::get(NRetTy);
for (unsigned i = 0; i != RetCount; ++i)
if (NewRetIdxs[i] != -1) {
ExtractValueInst *EV = ExtractValueInst::Create(OldRet, i,
}
// Replace the return instruction with one returning the new return
// value (possibly 0 if we became void).
- ReturnInst::Create(RetVal, RI);
+ ReturnInst::Create(F->getContext(), RetVal, RI);
BB->getInstList().erase(RI);
}
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