#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
-#include "llvm/Support/Compiler.h"
#include <map>
#include <set>
using namespace llvm;
namespace {
/// DAE - The dead argument elimination pass.
///
- class VISIBILITY_HIDDEN DAE : public ModulePass {
+ class DAE : public ModulePass {
public:
/// Struct that represents (part of) either a return value or a function
/// argument. Used so that arguments and return values can be used
/// interchangably.
struct RetOrArg {
- RetOrArg(const Function* F, unsigned Idx, bool IsArg) : F(F), Idx(Idx),
+ RetOrArg(const Function *F, unsigned Idx, bool IsArg) : F(F), Idx(Idx),
IsArg(IsArg) {}
const Function *F;
unsigned Idx;
}
std::string getDescription() const {
- return std::string((IsArg ? "Argument #" : "Return value #"))
+ return std::string((IsArg ? "Argument #" : "Return value #"))
+ utostr(Idx) + " of function " + F->getNameStr();
}
};
typedef SmallVector<RetOrArg, 5> UseVector;
+ protected:
+ // DAH uses this to specify a different ID.
+ explicit DAE(void *ID) : ModulePass(ID) {}
+
public:
static char ID; // Pass identification, replacement for typeid
DAE() : ModulePass(&ID) {}
+
bool runOnModule(Module &M);
virtual bool ShouldHackArguments() const { return false; }
private:
Liveness MarkIfNotLive(RetOrArg Use, UseVector &MaybeLiveUses);
- Liveness SurveyUse(Value::use_iterator U, UseVector &MaybeLiveUses,
+ Liveness SurveyUse(Value::const_use_iterator U, UseVector &MaybeLiveUses,
unsigned RetValNum = 0);
- Liveness SurveyUses(Value *V, UseVector &MaybeLiveUses);
+ Liveness SurveyUses(const Value *V, UseVector &MaybeLiveUses);
- void SurveyFunction(Function &F);
+ void SurveyFunction(const Function &F);
void MarkValue(const RetOrArg &RA, Liveness L,
const UseVector &MaybeLiveUses);
void MarkLive(const RetOrArg &RA);
char DAE::ID = 0;
-static RegisterPass<DAE>
-X("deadargelim", "Dead Argument Elimination");
+INITIALIZE_PASS(DAE, "deadargelim", "Dead Argument Elimination", false, false);
namespace {
/// DAH - DeadArgumentHacking pass - Same as dead argument elimination, but
/// by bugpoint.
struct DAH : public DAE {
static char ID;
+ DAH() : DAE(&ID) {}
+
virtual bool ShouldHackArguments() const { return true; }
};
}
char DAH::ID = 0;
-static RegisterPass<DAH>
-Y("deadarghaX0r", "Dead Argument Hacking (BUGPOINT USE ONLY; DO NOT USE)");
+INITIALIZE_PASS(DAH, "deadarghaX0r",
+ "Dead Argument Hacking (BUGPOINT USE ONLY; DO NOT USE)",
+ false, false);
/// createDeadArgEliminationPass - This pass removes arguments from functions
/// which are not used by the body of the function.
// 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);
SmallVector<AttributeWithIndex, 8> AttributesVec;
for (unsigned i = 0; PAL.getSlot(i).Index <= NumArgs; ++i)
AttributesVec.push_back(PAL.getSlot(i));
- if (Attributes FnAttrs = PAL.getFnAttributes())
+ if (Attributes FnAttrs = PAL.getFnAttributes())
AttributesVec.push_back(AttributeWithIndex::get(~0, FnAttrs));
PAL = AttrListPtr::get(AttributesVec.begin(), AttributesVec.end());
}
if (cast<CallInst>(Call)->isTailCall())
cast<CallInst>(New)->setTailCall();
}
+ New->setDebugLoc(Call->getDebugLoc());
+
Args.clear();
if (!Call->use_empty())
/// 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()->isVoidTy())
return 0;
else if (const StructType *STy = dyn_cast<StructType>(F->getReturnType()))
return STy->getNumElements();
/// SurveyUse - This looks at a single use of an argument or return value
/// and determines if it should be alive or not. Adds this use to MaybeLiveUses
-/// if it causes the used value to become MaybeAlive.
+/// if it causes the used value to become MaybeLive.
///
/// RetValNum is the return value number to use when this use is used in a
/// return instruction. This is used in the recursion, you should always leave
/// it at 0.
-DAE::Liveness DAE::SurveyUse(Value::use_iterator U, UseVector &MaybeLiveUses,
- unsigned RetValNum) {
- Value *V = *U;
- if (ReturnInst *RI = dyn_cast<ReturnInst>(V)) {
+DAE::Liveness DAE::SurveyUse(Value::const_use_iterator U,
+ UseVector &MaybeLiveUses, unsigned RetValNum) {
+ const User *V = *U;
+ if (const ReturnInst *RI = dyn_cast<ReturnInst>(V)) {
// The value is returned from a function. It's only live when the
// function's return value is live. We use RetValNum here, for the case
// that U is really a use of an insertvalue instruction that uses the
// We might be live, depending on the liveness of Use.
return MarkIfNotLive(Use, MaybeLiveUses);
}
- if (InsertValueInst *IV = dyn_cast<InsertValueInst>(V)) {
+ if (const InsertValueInst *IV = dyn_cast<InsertValueInst>(V)) {
if (U.getOperandNo() != InsertValueInst::getAggregateOperandIndex()
&& IV->hasIndices())
// The use we are examining is inserted into an aggregate. Our liveness
// we don't change RetValNum, but do survey all our uses.
Liveness Result = MaybeLive;
- for (Value::use_iterator I = IV->use_begin(),
+ for (Value::const_use_iterator I = IV->use_begin(),
E = V->use_end(); I != E; ++I) {
Result = SurveyUse(I, MaybeLiveUses, RetValNum);
if (Result == Live)
}
return Result;
}
- CallSite CS = CallSite::get(V);
- if (CS.getInstruction()) {
- Function *F = CS.getCalledFunction();
+
+ if (ImmutableCallSite CS = V) {
+ const Function *F = CS.getCalledFunction();
if (F) {
// Used in a direct call.
-
+
// Find the argument number. We know for sure that this use is an
// argument, since if it was the function argument this would be an
// indirect call and the we know can't be looking at a value of the
// label type (for the invoke instruction).
- unsigned ArgNo = CS.getArgumentNo(U.getOperandNo());
+ unsigned ArgNo = CS.getArgumentNo(U);
if (ArgNo >= F->getFunctionType()->getNumParams())
// The value is passed in through a vararg! Must be live.
return Live;
- assert(CS.getArgument(ArgNo)
- == CS.getInstruction()->getOperand(U.getOperandNo())
+ assert(CS.getArgument(ArgNo)
+ == CS->getOperand(U.getOperandNo())
&& "Argument is not where we expected it");
// Value passed to a normal call. It's only live when the corresponding
/// Adds all uses that cause the result to be MaybeLive to MaybeLiveRetUses. If
/// the result is Live, MaybeLiveUses might be modified but its content should
/// be ignored (since it might not be complete).
-DAE::Liveness DAE::SurveyUses(Value *V, UseVector &MaybeLiveUses) {
+DAE::Liveness DAE::SurveyUses(const Value *V, UseVector &MaybeLiveUses) {
// Assume it's dead (which will only hold if there are no uses at all..).
Liveness Result = MaybeLive;
// Check each use.
- for (Value::use_iterator I = V->use_begin(),
+ for (Value::const_use_iterator I = V->use_begin(),
E = V->use_end(); I != E; ++I) {
Result = SurveyUse(I, MaybeLiveUses);
if (Result == Live)
// We consider arguments of non-internal functions to be intrinsically alive as
// well as arguments to functions which have their "address taken".
//
-void DAE::SurveyFunction(Function &F) {
+void DAE::SurveyFunction(const Function &F) {
unsigned RetCount = NumRetVals(&F);
// Assume all return values are dead
typedef SmallVector<Liveness, 5> RetVals;
// MaybeLive. Initialized to a list of RetCount empty lists.
RetUses MaybeLiveRetUses(RetCount);
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
- if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator()))
+ for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+ if (const ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator()))
if (RI->getNumOperands() != 0 && RI->getOperand(0)->getType()
!= F.getFunctionType()->getReturnType()) {
// We don't support old style multiple return values.
return;
}
- DEBUG(errs() << "DAE - Inspecting callers for fn: " << F.getName() << "\n");
+ DEBUG(dbgs() << "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;
const Type *STy = dyn_cast<StructType>(F.getReturnType());
// Loop all uses of the function.
- for (Value::use_iterator I = F.use_begin(), E = F.use_end(); I != E; ++I) {
+ for (Value::const_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.
- CallSite CS = CallSite::get(*I);
- if (!CS.getInstruction() || !CS.isCallee(I)) {
+ ImmutableCallSite CS(*I);
+ if (!CS || !CS.isCallee(I)) {
MarkLive(F);
return;
}
// If this use is anything other than a call site, the function is alive.
- Instruction *TheCall = CS.getInstruction();
+ const Instruction *TheCall = CS.getInstruction();
if (!TheCall) { // Not a direct call site?
MarkLive(F);
return;
if (NumLiveRetVals != RetCount) {
if (STy) {
// Check all uses of the return value.
- for (Value::use_iterator I = TheCall->use_begin(),
+ for (Value::const_use_iterator I = TheCall->use_begin(),
E = TheCall->use_end(); I != E; ++I) {
- ExtractValueInst *Ext = dyn_cast<ExtractValueInst>(*I);
+ const ExtractValueInst *Ext = dyn_cast<ExtractValueInst>(*I);
if (Ext && Ext->hasIndices()) {
// This use uses a part of our return value, survey the uses of
// that part and store the results for this index only.
for (unsigned i = 0; i != RetCount; ++i)
MarkValue(CreateRet(&F, i), RetValLiveness[i], MaybeLiveRetUses[i]);
- DEBUG(errs() << "DAE - Inspecting args for fn: " << F.getName() << "\n");
+ DEBUG(dbgs() << "DAE - Inspecting args for fn: " << F.getName() << "\n");
// Now, check all of our arguments.
unsigned i = 0;
UseVector MaybeLiveArgUses;
- for (Function::arg_iterator AI = F.arg_begin(),
+ for (Function::const_arg_iterator AI = F.arg_begin(),
E = F.arg_end(); AI != E; ++AI, ++i) {
// See what the effect of this use is (recording any uses that cause
// MaybeLive in MaybeLiveArgUses).
/// 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) {
- 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)
- PropagateLiveness(CreateArg(&F, i));
- // Mark all return values as live.
- for (unsigned i = 0, e = NumRetVals(&F); i != e; ++i)
- PropagateLiveness(CreateRet(&F, i));
+ DEBUG(dbgs() << "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)
+ PropagateLiveness(CreateArg(&F, i));
+ // Mark all return values as live.
+ for (unsigned i = 0, e = NumRetVals(&F); i != e; ++i)
+ PropagateLiveness(CreateRet(&F, i));
}
/// MarkLive - Mark the given return value or argument as live. Additionally,
if (!LiveValues.insert(RA).second)
return; // We were already marked Live.
- DOUT << "DAE - Marking " << RA.getDescription() << " live\n";
+ DEBUG(dbgs() << "DAE - Marking " << RA.getDescription() << " live\n");
PropagateLiveness(RA);
}
const Type *RetTy = FTy->getReturnType();
const Type *NRetTy = NULL;
unsigned RetCount = NumRetVals(F);
-
- LLVMContext &Context = RetTy->getContext();
-
+
// -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->isVoidTy()) {
+ NRetTy = RetTy;
} else {
const StructType *STy = dyn_cast<StructType>(RetTy);
if (STy)
NewRetIdxs[i] = RetTypes.size() - 1;
} else {
++NumRetValsEliminated;
- DEBUG(errs() << "DAE - Removing return value " << i << " from "
+ DEBUG(dbgs() << "DAE - Removing return value " << i << " from "
<< F->getName() << "\n");
}
}
RetTypes.push_back(RetTy);
NewRetIdxs[0] = 0;
} else {
- DEBUG(errs() << "DAE - Removing return value from " << F->getName()
+ DEBUG(dbgs() << "DAE - Removing return value from " << F->getName()
<< "\n");
++NumRetValsEliminated;
}
// 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)
+ if (NRetTy->isVoidTy())
RAttrs &= ~Attribute::typeIncompatible(NRetTy);
else
- assert((RAttrs & Attribute::typeIncompatible(NRetTy)) == 0
+ assert((RAttrs & Attribute::typeIncompatible(NRetTy)) == 0
&& "Return attributes no longer compatible?");
if (RAttrs)
AttributesVec.push_back(AttributeWithIndex::get(Params.size(), Attrs));
} else {
++NumArgumentsEliminated;
- DEBUG(errs() << "DAE - Removing argument " << i << " (" << I->getName()
+ DEBUG(dbgs() << "DAE - Removing argument " << i << " (" << I->getName()
<< ") from " << F->getName() << "\n");
}
}
- if (FnAttrs != Attribute::None)
+ 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.
- //
- // Note that we apply this hack for a vararg fuction that does not have any
- // arguments anymore, but did have them before (so don't bother fixing
- // functions that were already broken wrt CWriter).
- bool ExtraArgHack = false;
- if (Params.empty() && FTy->isVarArg() && FTy->getNumParams() != 0) {
- ExtraArgHack = true;
- Params.push_back(Type::Int32Ty);
- }
+ AttrListPtr NewPAL = AttrListPtr::get(AttributesVec.begin(),
+ AttributesVec.end());
// 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)
AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs));
}
- if (ExtraArgHack)
- Args.push_back(UndefValue::get(Type::Int32Ty));
-
// 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 (cast<CallInst>(Call)->isTailCall())
cast<CallInst>(New)->setTailCall();
}
+ New->setDebugLoc(Call->getDebugLoc());
+
Args.clear();
if (!Call->use_empty()) {
// Return type not changed? Just replace users then.
Call->replaceAllUsesWith(New);
New->takeName(Call);
- } else if (New->getType() == Type::VoidTy) {
+ } else if (New->getType()->isVoidTy()) {
// Our return value has uses, but they will get removed later on.
// Replace by null for now.
- Call->replaceAllUsesWith(Context.getNullValue(Call->getType()));
+ Call->replaceAllUsesWith(Constant::getNullValue(Call->getType()));
} else {
- assert(isa<StructType>(RetTy) &&
+ assert(RetTy->isStructTy() &&
"Return type changed, but not into a void. The old return type"
" must have been a struct!");
Instruction *InsertPt = Call;
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.
} else {
// If this argument is dead, replace any uses of it with null constants
// (these are guaranteed to become unused later on).
- I->replaceAllUsesWith(Context.getNullValue(I->getType()));
+ I->replaceAllUsesWith(Constant::getNullValue(I->getType()));
}
// If we change the return value of the function we must rewrite any return
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
Value *RetVal;
- if (NFTy->getReturnType() == Type::VoidTy) {
+ if (NFTy->getReturnType()->isVoidTy()) {
RetVal = 0;
} else {
- assert (isa<StructType>(RetTy));
+ assert (RetTy->isStructTy());
// The original return value was a struct, insert
// extractvalue/insertvalue chains to extract only the values we need
// to return and insert them into our new result.
}
// 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);
}
// removed. We can do this if they never call va_start. This loop cannot be
// fused with the next loop, because deleting a function invalidates
// information computed while surveying other functions.
- DOUT << "DAE - Deleting dead varargs\n";
+ DEBUG(dbgs() << "DAE - Deleting dead varargs\n");
for (Module::iterator I = M.begin(), E = M.end(); I != E; ) {
Function &F = *I++;
if (F.getFunctionType()->isVarArg())
// We assume all arguments are dead unless proven otherwise (allowing us to
// determine that dead arguments passed into recursive functions are dead).
//
- DOUT << "DAE - Determining liveness\n";
+ DEBUG(dbgs() << "DAE - Determining liveness\n");
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
SurveyFunction(*I);
-
+
// Now, remove all dead arguments and return values from each function in
- // turn
+ // turn.
for (Module::iterator I = M.begin(), E = M.end(); I != E; ) {
- // Increment now, because the function will probably get removed (ie
+ // Increment now, because the function will probably get removed (ie.
// replaced by a new one).
Function *F = I++;
Changed |= RemoveDeadStuffFromFunction(F);
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