maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/lib/IR/Function.cpp

708 lines
23 KiB
C++
Raw Blame History

//===-- Function.cpp - Implement the Global object classes ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Function class for the IR library.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/Function.h"
#include "LLVMContextImpl.h"
#include "SymbolTableListTraitsImpl.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/LeakDetector.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/RWMutex.h"
#include "llvm/Support/StringPool.h"
#include "llvm/Support/Threading.h"
using namespace llvm;
// Explicit instantiations of SymbolTableListTraits since some of the methods
// are not in the public header file...
template class llvm::SymbolTableListTraits<Argument, Function>;
template class llvm::SymbolTableListTraits<BasicBlock, Function>;
//===----------------------------------------------------------------------===//
// Argument Implementation
//===----------------------------------------------------------------------===//
void Argument::anchor() { }
Argument::Argument(Type *Ty, const Twine &Name, Function *Par)
: Value(Ty, Value::ArgumentVal) {
Parent = 0;
// Make sure that we get added to a function
LeakDetector::addGarbageObject(this);
if (Par)
Par->getArgumentList().push_back(this);
setName(Name);
}
void Argument::setParent(Function *parent) {
if (getParent())
LeakDetector::addGarbageObject(this);
Parent = parent;
if (getParent())
LeakDetector::removeGarbageObject(this);
}
/// getArgNo - Return the index of this formal argument in its containing
/// function. For example in "void foo(int a, float b)" a is 0 and b is 1.
unsigned Argument::getArgNo() const {
const Function *F = getParent();
assert(F && "Argument is not in a function");
Function::const_arg_iterator AI = F->arg_begin();
unsigned ArgIdx = 0;
for (; &*AI != this; ++AI)
++ArgIdx;
return ArgIdx;
}
/// hasByValAttr - Return true if this argument has the byval attribute on it
/// in its containing function.
bool Argument::hasByValAttr() const {
if (!getType()->isPointerTy()) return false;
return getParent()->getAttributes().
hasAttribute(getArgNo()+1, Attribute::ByVal);
}
unsigned Argument::getParamAlignment() const {
assert(getType()->isPointerTy() && "Only pointers have alignments");
return getParent()->getParamAlignment(getArgNo()+1);
}
/// hasNestAttr - Return true if this argument has the nest attribute on
/// it in its containing function.
bool Argument::hasNestAttr() const {
if (!getType()->isPointerTy()) return false;
return getParent()->getAttributes().
hasAttribute(getArgNo()+1, Attribute::Nest);
}
/// hasNoAliasAttr - Return true if this argument has the noalias attribute on
/// it in its containing function.
bool Argument::hasNoAliasAttr() const {
if (!getType()->isPointerTy()) return false;
return getParent()->getAttributes().
hasAttribute(getArgNo()+1, Attribute::NoAlias);
}
/// hasNoCaptureAttr - Return true if this argument has the nocapture attribute
/// on it in its containing function.
bool Argument::hasNoCaptureAttr() const {
if (!getType()->isPointerTy()) return false;
return getParent()->getAttributes().
hasAttribute(getArgNo()+1, Attribute::NoCapture);
}
/// hasSRetAttr - Return true if this argument has the sret attribute on
/// it in its containing function.
bool Argument::hasStructRetAttr() const {
if (!getType()->isPointerTy()) return false;
if (this != getParent()->arg_begin())
return false; // StructRet param must be first param
return getParent()->getAttributes().
hasAttribute(1, Attribute::StructRet);
}
/// addAttr - Add attributes to an argument.
void Argument::addAttr(AttributeSet AS) {
assert(AS.getNumSlots() <= 1 &&
"Trying to add more than one attribute set to an argument!");
AttrBuilder B(AS, AS.getSlotIndex(0));
getParent()->addAttributes(getArgNo() + 1,
AttributeSet::get(Parent->getContext(),
getArgNo() + 1, B));
}
/// removeAttr - Remove attributes from an argument.
void Argument::removeAttr(AttributeSet AS) {
assert(AS.getNumSlots() <= 1 &&
"Trying to remove more than one attribute set from an argument!");
AttrBuilder B(AS, AS.getSlotIndex(0));
getParent()->removeAttributes(getArgNo() + 1,
AttributeSet::get(Parent->getContext(),
getArgNo() + 1, B));
}
//===----------------------------------------------------------------------===//
// Helper Methods in Function
//===----------------------------------------------------------------------===//
LLVMContext &Function::getContext() const {
return getType()->getContext();
}
FunctionType *Function::getFunctionType() const {
return cast<FunctionType>(getType()->getElementType());
}
bool Function::isVarArg() const {
return getFunctionType()->isVarArg();
}
Type *Function::getReturnType() const {
return getFunctionType()->getReturnType();
}
void Function::removeFromParent() {
getParent()->getFunctionList().remove(this);
}
void Function::eraseFromParent() {
getParent()->getFunctionList().erase(this);
}
//===----------------------------------------------------------------------===//
// Function Implementation
//===----------------------------------------------------------------------===//
Function::Function(FunctionType *Ty, LinkageTypes Linkage,
const Twine &name, Module *ParentModule)
: GlobalValue(PointerType::getUnqual(Ty),
Value::FunctionVal, 0, 0, Linkage, name) {
assert(FunctionType::isValidReturnType(getReturnType()) &&
"invalid return type");
SymTab = new ValueSymbolTable();
// If the function has arguments, mark them as lazily built.
if (Ty->getNumParams())
setValueSubclassData(1); // Set the "has lazy arguments" bit.
// Make sure that we get added to a function
LeakDetector::addGarbageObject(this);
if (ParentModule)
ParentModule->getFunctionList().push_back(this);
// Ensure intrinsics have the right parameter attributes.
if (unsigned IID = getIntrinsicID())
setAttributes(Intrinsic::getAttributes(getContext(), Intrinsic::ID(IID)));
}
Function::~Function() {
dropAllReferences(); // After this it is safe to delete instructions.
// Delete all of the method arguments and unlink from symbol table...
ArgumentList.clear();
delete SymTab;
// Remove the function from the on-the-side GC table.
clearGC();
// Remove the intrinsicID from the Cache.
if (getValueName() && isIntrinsic())
getContext().pImpl->IntrinsicIDCache.erase(this);
}
void Function::BuildLazyArguments() const {
// Create the arguments vector, all arguments start out unnamed.
FunctionType *FT = getFunctionType();
for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
assert(!FT->getParamType(i)->isVoidTy() &&
"Cannot have void typed arguments!");
ArgumentList.push_back(new Argument(FT->getParamType(i)));
}
// Clear the lazy arguments bit.
unsigned SDC = getSubclassDataFromValue();
const_cast<Function*>(this)->setValueSubclassData(SDC &= ~1);
}
size_t Function::arg_size() const {
return getFunctionType()->getNumParams();
}
bool Function::arg_empty() const {
return getFunctionType()->getNumParams() == 0;
}
void Function::setParent(Module *parent) {
if (getParent())
LeakDetector::addGarbageObject(this);
Parent = parent;
if (getParent())
LeakDetector::removeGarbageObject(this);
}
// dropAllReferences() - This function causes all the subinstructions to "let
// go" of all references that they are maintaining. This allows one to
// 'delete' a whole class at a time, even though there may be circular
// references... first all references are dropped, and all use counts go to
// zero. Then everything is deleted for real. Note that no operations are
// valid on an object that has "dropped all references", except operator
// delete.
//
void Function::dropAllReferences() {
for (iterator I = begin(), E = end(); I != E; ++I)
I->dropAllReferences();
// Delete all basic blocks. They are now unused, except possibly by
// blockaddresses, but BasicBlock's destructor takes care of those.
while (!BasicBlocks.empty())
BasicBlocks.begin()->eraseFromParent();
}
void Function::addAttribute(unsigned i, Attribute::AttrKind attr) {
AttributeSet PAL = getAttributes();
PAL = PAL.addAttribute(getContext(), i, attr);
setAttributes(PAL);
}
void Function::addAttributes(unsigned i, AttributeSet attrs) {
AttributeSet PAL = getAttributes();
PAL = PAL.addAttributes(getContext(), i, attrs);
setAttributes(PAL);
}
void Function::removeAttributes(unsigned i, AttributeSet attrs) {
AttributeSet PAL = getAttributes();
PAL = PAL.removeAttributes(getContext(), i, attrs);
setAttributes(PAL);
}
// Maintain the GC name for each function in an on-the-side table. This saves
// allocating an additional word in Function for programs which do not use GC
// (i.e., most programs) at the cost of increased overhead for clients which do
// use GC.
static DenseMap<const Function*,PooledStringPtr> *GCNames;
static StringPool *GCNamePool;
static ManagedStatic<sys::SmartRWMutex<true> > GCLock;
bool Function::hasGC() const {
sys::SmartScopedReader<true> Reader(*GCLock);
return GCNames && GCNames->count(this);
}
const char *Function::getGC() const {
assert(hasGC() && "Function has no collector");
sys::SmartScopedReader<true> Reader(*GCLock);
return *(*GCNames)[this];
}
void Function::setGC(const char *Str) {
sys::SmartScopedWriter<true> Writer(*GCLock);
if (!GCNamePool)
GCNamePool = new StringPool();
if (!GCNames)
GCNames = new DenseMap<const Function*,PooledStringPtr>();
(*GCNames)[this] = GCNamePool->intern(Str);
}
void Function::clearGC() {
sys::SmartScopedWriter<true> Writer(*GCLock);
if (GCNames) {
GCNames->erase(this);
if (GCNames->empty()) {
delete GCNames;
GCNames = 0;
if (GCNamePool->empty()) {
delete GCNamePool;
GCNamePool = 0;
}
}
}
}
/// copyAttributesFrom - copy all additional attributes (those not needed to
/// create a Function) from the Function Src to this one.
void Function::copyAttributesFrom(const GlobalValue *Src) {
assert(isa<Function>(Src) && "Expected a Function!");
GlobalValue::copyAttributesFrom(Src);
const Function *SrcF = cast<Function>(Src);
setCallingConv(SrcF->getCallingConv());
setAttributes(SrcF->getAttributes());
if (SrcF->hasGC())
setGC(SrcF->getGC());
else
clearGC();
}
/// getIntrinsicID - This method returns the ID number of the specified
/// function, or Intrinsic::not_intrinsic if the function is not an
/// intrinsic, or if the pointer is null. This value is always defined to be
/// zero to allow easy checking for whether a function is intrinsic or not. The
/// particular intrinsic functions which correspond to this value are defined in
/// llvm/Intrinsics.h. Results are cached in the LLVM context, subsequent
/// requests for the same ID return results much faster from the cache.
///
unsigned Function::getIntrinsicID() const {
const ValueName *ValName = this->getValueName();
if (!ValName || !isIntrinsic())
return 0;
LLVMContextImpl::IntrinsicIDCacheTy &IntrinsicIDCache =
getContext().pImpl->IntrinsicIDCache;
if (!IntrinsicIDCache.count(this)) {
unsigned Id = lookupIntrinsicID();
IntrinsicIDCache[this]=Id;
return Id;
}
return IntrinsicIDCache[this];
}
/// This private method does the actual lookup of an intrinsic ID when the query
/// could not be answered from the cache.
unsigned Function::lookupIntrinsicID() const {
const ValueName *ValName = this->getValueName();
unsigned Len = ValName->getKeyLength();
const char *Name = ValName->getKeyData();
#define GET_FUNCTION_RECOGNIZER
#include "llvm/IR/Intrinsics.gen"
#undef GET_FUNCTION_RECOGNIZER
return 0;
}
std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) {
assert(id < num_intrinsics && "Invalid intrinsic ID!");
static const char * const Table[] = {
"not_intrinsic",
#define GET_INTRINSIC_NAME_TABLE
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_NAME_TABLE
};
if (Tys.empty())
return Table[id];
std::string Result(Table[id]);
for (unsigned i = 0; i < Tys.size(); ++i) {
if (PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) {
Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) +
EVT::getEVT(PTyp->getElementType()).getEVTString();
}
else if (Tys[i])
Result += "." + EVT::getEVT(Tys[i]).getEVTString();
}
return Result;
}
/// IIT_Info - These are enumerators that describe the entries returned by the
/// getIntrinsicInfoTableEntries function.
///
/// NOTE: This must be kept in synch with the copy in TblGen/IntrinsicEmitter!
enum IIT_Info {
// Common values should be encoded with 0-15.
IIT_Done = 0,
IIT_I1 = 1,
IIT_I8 = 2,
IIT_I16 = 3,
IIT_I32 = 4,
IIT_I64 = 5,
IIT_F16 = 6,
IIT_F32 = 7,
IIT_F64 = 8,
IIT_V2 = 9,
IIT_V4 = 10,
IIT_V8 = 11,
IIT_V16 = 12,
IIT_V32 = 13,
IIT_PTR = 14,
IIT_ARG = 15,
// Values from 16+ are only encodable with the inefficient encoding.
IIT_MMX = 16,
IIT_METADATA = 17,
IIT_EMPTYSTRUCT = 18,
IIT_STRUCT2 = 19,
IIT_STRUCT3 = 20,
IIT_STRUCT4 = 21,
IIT_STRUCT5 = 22,
IIT_EXTEND_VEC_ARG = 23,
IIT_TRUNC_VEC_ARG = 24,
IIT_ANYPTR = 25
};
static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
IIT_Info Info = IIT_Info(Infos[NextElt++]);
unsigned StructElts = 2;
using namespace Intrinsic;
switch (Info) {
case IIT_Done:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Void, 0));
return;
case IIT_MMX:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::MMX, 0));
return;
case IIT_METADATA:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Metadata, 0));
return;
case IIT_F16:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Half, 0));
return;
case IIT_F32:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Float, 0));
return;
case IIT_F64:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Double, 0));
return;
case IIT_I1:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 1));
return;
case IIT_I8:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 8));
return;
case IIT_I16:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer,16));
return;
case IIT_I32:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 32));
return;
case IIT_I64:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 64));
return;
case IIT_V2:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 2));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V4:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 4));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V8:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 8));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V16:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 16));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V32:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 32));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_PTR:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer, 0));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_ANYPTR: { // [ANYPTR addrspace, subtype]
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer,
Infos[NextElt++]));
DecodeIITType(NextElt, Infos, OutputTable);
return;
}
case IIT_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Argument, ArgInfo));
return;
}
case IIT_EXTEND_VEC_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::ExtendVecArgument,
ArgInfo));
return;
}
case IIT_TRUNC_VEC_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::TruncVecArgument,
ArgInfo));
return;
}
case IIT_EMPTYSTRUCT:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
return;
case IIT_STRUCT5: ++StructElts; // FALL THROUGH.
case IIT_STRUCT4: ++StructElts; // FALL THROUGH.
case IIT_STRUCT3: ++StructElts; // FALL THROUGH.
case IIT_STRUCT2: {
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
for (unsigned i = 0; i != StructElts; ++i)
DecodeIITType(NextElt, Infos, OutputTable);
return;
}
}
llvm_unreachable("unhandled");
}
#define GET_INTRINSIC_GENERATOR_GLOBAL
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_GENERATOR_GLOBAL
void Intrinsic::getIntrinsicInfoTableEntries(ID id,
SmallVectorImpl<IITDescriptor> &T){
// Check to see if the intrinsic's type was expressible by the table.
unsigned TableVal = IIT_Table[id-1];
// Decode the TableVal into an array of IITValues.
SmallVector<unsigned char, 8> IITValues;
ArrayRef<unsigned char> IITEntries;
unsigned NextElt = 0;
if ((TableVal >> 31) != 0) {
// This is an offset into the IIT_LongEncodingTable.
IITEntries = IIT_LongEncodingTable;
// Strip sentinel bit.
NextElt = (TableVal << 1) >> 1;
} else {
// Decode the TableVal into an array of IITValues. If the entry was encoded
// into a single word in the table itself, decode it now.
do {
IITValues.push_back(TableVal & 0xF);
TableVal >>= 4;
} while (TableVal);
IITEntries = IITValues;
NextElt = 0;
}
// Okay, decode the table into the output vector of IITDescriptors.
DecodeIITType(NextElt, IITEntries, T);
while (NextElt != IITEntries.size() && IITEntries[NextElt] != 0)
DecodeIITType(NextElt, IITEntries, T);
}
static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,
ArrayRef<Type*> Tys, LLVMContext &Context) {
using namespace Intrinsic;
IITDescriptor D = Infos.front();
Infos = Infos.slice(1);
switch (D.Kind) {
case IITDescriptor::Void: return Type::getVoidTy(Context);
case IITDescriptor::MMX: return Type::getX86_MMXTy(Context);
case IITDescriptor::Metadata: return Type::getMetadataTy(Context);
case IITDescriptor::Half: return Type::getHalfTy(Context);
case IITDescriptor::Float: return Type::getFloatTy(Context);
case IITDescriptor::Double: return Type::getDoubleTy(Context);
case IITDescriptor::Integer:
return IntegerType::get(Context, D.Integer_Width);
case IITDescriptor::Vector:
return VectorType::get(DecodeFixedType(Infos, Tys, Context),D.Vector_Width);
case IITDescriptor::Pointer:
return PointerType::get(DecodeFixedType(Infos, Tys, Context),
D.Pointer_AddressSpace);
case IITDescriptor::Struct: {
Type *Elts[5];
assert(D.Struct_NumElements <= 5 && "Can't handle this yet");
for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
Elts[i] = DecodeFixedType(Infos, Tys, Context);
return StructType::get(Context, ArrayRef<Type*>(Elts,D.Struct_NumElements));
}
case IITDescriptor::Argument:
return Tys[D.getArgumentNumber()];
case IITDescriptor::ExtendVecArgument:
return VectorType::getExtendedElementVectorType(cast<VectorType>(
Tys[D.getArgumentNumber()]));
case IITDescriptor::TruncVecArgument:
return VectorType::getTruncatedElementVectorType(cast<VectorType>(
Tys[D.getArgumentNumber()]));
}
llvm_unreachable("unhandled");
}
FunctionType *Intrinsic::getType(LLVMContext &Context,
ID id, ArrayRef<Type*> Tys) {
SmallVector<IITDescriptor, 8> Table;
getIntrinsicInfoTableEntries(id, Table);
ArrayRef<IITDescriptor> TableRef = Table;
Type *ResultTy = DecodeFixedType(TableRef, Tys, Context);
SmallVector<Type*, 8> ArgTys;
while (!TableRef.empty())
ArgTys.push_back(DecodeFixedType(TableRef, Tys, Context));
return FunctionType::get(ResultTy, ArgTys, false);
}
bool Intrinsic::isOverloaded(ID id) {
#define GET_INTRINSIC_OVERLOAD_TABLE
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_OVERLOAD_TABLE
}
/// This defines the "Intrinsic::getAttributes(ID id)" method.
#define GET_INTRINSIC_ATTRIBUTES
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_ATTRIBUTES
Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
// There can never be multiple globals with the same name of different types,
// because intrinsics must be a specific type.
return
cast<Function>(M->getOrInsertFunction(getName(id, Tys),
getType(M->getContext(), id, Tys)));
}
// This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
#define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
#include "llvm/IR/Intrinsics.gen"
#undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
/// hasAddressTaken - returns true if there are any uses of this function
/// other than direct calls or invokes to it.
bool Function::hasAddressTaken(const User* *PutOffender) const {
for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) {
const User *U = *I;
if (isa<BlockAddress>(U))
continue;
if (!isa<CallInst>(U) && !isa<InvokeInst>(U))
return PutOffender ? (*PutOffender = U, true) : true;
ImmutableCallSite CS(cast<Instruction>(U));
if (!CS.isCallee(I))
return PutOffender ? (*PutOffender = U, true) : true;
}
return false;
}
bool Function::isDefTriviallyDead() const {
// Check the linkage
if (!hasLinkOnceLinkage() && !hasLocalLinkage() &&
!hasAvailableExternallyLinkage())
return false;
// Check if the function is used by anything other than a blockaddress.
for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I)
if (!isa<BlockAddress>(*I))
return false;
return true;
}
/// callsFunctionThatReturnsTwice - Return true if the function has a call to
/// setjmp or other function that gcc recognizes as "returning twice".
bool Function::callsFunctionThatReturnsTwice() const {
for (const_inst_iterator
I = inst_begin(this), E = inst_end(this); I != E; ++I) {
const CallInst* callInst = dyn_cast<CallInst>(&*I);
if (!callInst)
continue;
if (callInst->canReturnTwice())
return true;
}
return false;
}
Reference in New Issue View Git Blame Copy Permalink