SVF::ObjTypeInference Class Reference

#include <ObjTypeInference.h>

Public Types
typedef Set< const Value * >	ValueSet
typedef Map< const Value *, ValueSet >	ValueToValueSet
typedef ValueToValueSet	ValueToInferSites
typedef ValueToValueSet	ValueToSources
typedef Map< const Value *, const Type * >	ValueToType
typedef std::pair< const Value *, bool >	ValueBoolPair
typedef Map< const Value *, Set< std::string > >	ValueToClassNames
typedef Map< const Value *, Set< const CallBase * > >	ObjToClsNameSources

Public Member Functions
	ObjTypeInference ()=default
	~ObjTypeInference ()=default
const Type *	inferObjType (const Value *var)
	get or infer the type of the object pointed by the value
const Type *	inferPointsToType (const Value *var)
void	validateTypeCheck (const CallBase *cs)
	validate type inference
void	typeSizeDiffTest (const PointerType *oPTy, const Type *iTy, const Value *val)
const Type *	defaultType (const Value *val)
	default type
const Type *	ptrType ()
	pointer type
const IntegerType *	int8Type ()
	int8 type
LLVMContext &	getLLVMCtx ()
const Type *	selectLargestSizedType (Set< const Type * > &objTys)
	select the largest (conservative) type from all types
u32_t	objTyToNumFields (const Type *objTy)
u32_t	getArgPosInCall (const CallBase *callBase, const Value *arg)
Set< std::string > &	inferThisPtrClsName (const Value *thisPtr)
	get or infer the class names of thisptr

Protected Member Functions
Set< const Value * > &	bwFindAllocOrClsNameSources (const Value *startValue)
Set< const CallBase * > &	fwFindClsNameSources (const Value *startValue)
	forward find class name sources starting from an allocation

Private Member Functions
const Type *	fwInferObjType (const Value *var)
	forward infer the type of the object pointed by var
Set< const Value * > &	bwfindAllocOfVar (const Value *var)
	backward collect all possible allocation sites (stack, static, heap) of var
bool	isAlloc (const SVF::Value *val)
	is allocation (stack, static, heap)

Private Attributes
ValueToInferSites	_valueToInferSites
ValueToType	_valueToType
ValueToSources	_valueToAllocs
ValueToClassNames	_thisPtrClassNames
ValueToSources	_valueToAllocOrClsNameSources
ObjToClsNameSources	_objToClsNameSources

Detailed Description

Definition at line 39 of file ObjTypeInference.h.

Member Typedef Documentation

ObjToClsNameSources

typedef Map<const Value *, Set<const CallBase *> > SVF::ObjTypeInference::ObjToClsNameSources

Definition at line 50 of file ObjTypeInference.h.

ValueBoolPair

typedef std::pair<const Value *, bool> SVF::ObjTypeInference::ValueBoolPair

Definition at line 48 of file ObjTypeInference.h.

ValueSet

typedef Set<const Value *> SVF::ObjTypeInference::ValueSet

Definition at line 43 of file ObjTypeInference.h.

ValueToClassNames

typedef Map<const Value *, Set<std::string> > SVF::ObjTypeInference::ValueToClassNames

Definition at line 49 of file ObjTypeInference.h.

ValueToInferSites

typedef ValueToValueSet SVF::ObjTypeInference::ValueToInferSites

Definition at line 45 of file ObjTypeInference.h.

ValueToSources

typedef ValueToValueSet SVF::ObjTypeInference::ValueToSources

Definition at line 46 of file ObjTypeInference.h.

ValueToType

typedef Map<const Value *, const Type *> SVF::ObjTypeInference::ValueToType

Definition at line 47 of file ObjTypeInference.h.

ValueToValueSet

typedef Map<const Value *, ValueSet> SVF::ObjTypeInference::ValueToValueSet

Definition at line 44 of file ObjTypeInference.h.

Constructor & Destructor Documentation

ObjTypeInference()

SVF::ObjTypeInference::ObjTypeInference ( )

explicitdefault

~ObjTypeInference()

SVF::ObjTypeInference::~ObjTypeInference ( )

default

Member Function Documentation

bwfindAllocOfVar()

Set< const Value * > & ObjTypeInference::bwfindAllocOfVar ( const Value *  var )

private

backward collect all possible allocation sites (stack, static, heap) of var

backward collect all possible allocation sites (stack, static, heap) of var

Parameters

var

Returns

Definition at line 533 of file ObjTypeInference.cpp.

{
 
    // consult cache
    auto tIt = _valueToAllocs.find(var);
    if (tIt != _valueToAllocs.end())
    {
        return tIt->second;
    }
 
    // simulate the call stack, the second element indicates whether we should update sources for current value
    FILOWorkList<ValueBoolPair> workList;
    Set<ValueBoolPair> visited;
    workList.push({var, false});
    while (!workList.empty())
    {
        auto curPair = workList.pop();
        if (visited.count(curPair)) continue;
        visited.insert(curPair);
        const Value *curValue = curPair.first;
        bool canUpdate = curPair.second;
 
        Set<const Value *> sources;
        auto insertAllocs = [&sources, &canUpdate](const Value *source)
        {
            if (canUpdate) sources.insert(source);
        };
        auto insertAllocsOrPushWorklist = [this, &sources, &workList, &canUpdate](const auto &pUser)
        {
            auto vIt = _valueToAllocs.find(pUser);
            if (canUpdate)
            {
                if (vIt != _valueToAllocs.end())
                {
                    sources.insert(vIt->second.begin(), vIt->second.end());
                }
            }
            else
            {
                if (vIt == _valueToAllocs.end()) workList.push({pUser, false});
            }
        };
 
        if (!canUpdate && !_valueToAllocs.count(curValue))
        {
            workList.push({curValue, true});
        }
 
        if (isAlloc(curValue))
        {
            insertAllocs(curValue);
        }
        else if (const auto *bitCastInst = SVFUtil::dyn_cast<BitCastInst>(curValue))
        {
            Value *prevVal = bitCastInst->getOperand(0);
            insertAllocsOrPushWorklist(prevVal);
        }
        else if (const auto *phiNode = SVFUtil::dyn_cast<PHINode>(curValue))
        {
            for (u32_t i = 0; i < phiNode->getNumOperands(); ++i)
            {
                insertAllocsOrPushWorklist(phiNode->getOperand(i));
            }
        }
        else if (const auto *loadInst = SVFUtil::dyn_cast<LoadInst>(curValue))
        {
            for (const auto use: loadInst->getPointerOperand()->users())
            {
                if (const StoreInst *storeInst = SVFUtil::dyn_cast<StoreInst>(use))
                {
                    if (storeInst->getPointerOperand() == loadInst->getPointerOperand())
                    {
                        insertAllocsOrPushWorklist(storeInst->getValueOperand());
                    }
                }
            }
        }
        else if (const auto *argument = SVFUtil::dyn_cast<Argument>(curValue))
        {
            for (const auto use: argument->getParent()->users())
            {
                if (const CallBase *callBase = SVFUtil::dyn_cast<CallBase>(use))
                {
                    // skip function as parameter
                    // e.g., call void @foo(%struct.ssl_ctx_st* %9, i32 (i8*, i32, i32, i8*)* @passwd_callback)
                    if (callBase->getCalledFunction() != argument->getParent()) continue;
                    u32_t pos = argument->getParent()->isVarArg() ? 0 : argument->getArgNo();
                    insertAllocsOrPushWorklist(callBase->getArgOperand(pos));
                }
            }
        }
        else if (const auto *callBase = SVFUtil::dyn_cast<CallBase>(curValue))
        {
            ABORT_IFNOT(!callBase->doesNotReturn(), "callbase does not return:" + dumpValueAndDbgInfo(callBase));
            if (Function *callee = callBase->getCalledFunction())
            {
                if (!callee->isDeclaration())
                {
 
                    LLVMModuleSet* llvmmodule = LLVMModuleSet::getLLVMModuleSet();
                    const BasicBlock* exitBB = llvmmodule->getFunExitBB(callee);
                    assert (exitBB && "exit bb is not a basic block?");
                    const Value *pValue = &exitBB->back();
                    const auto *retInst = SVFUtil::dyn_cast<ReturnInst>(pValue);
                    ABORT_IFNOT(retInst && retInst->getReturnValue(), "not return inst?");
                    insertAllocsOrPushWorklist(retInst->getReturnValue());
                }
            }
        }
        if (canUpdate)
        {
            _valueToAllocs[curValue] = SVFUtil::move(sources);
        }
    }
    Set<const Value *> &srcs = _valueToAllocs[var];
    if (srcs.empty())
    {
        WARN_MSG("Cannot find allocation: " + dumpValueAndDbgInfo(var));
    }
    return srcs;
}

bwFindAllocOrClsNameSources()

Set< const Value * > & ObjTypeInference::bwFindAllocOrClsNameSources ( const Value *  startValue )

protected

find all possible allocations or class name sources (e.g., constructors/destructors or template functions) starting from a value

find all possible allocations or class name sources (e.g., constructors/destructors or template functions) if we already find class name sources, we don't need to find the allocations and forward find class name sources

Parameters

startValue

Returns

Definition at line 826 of file ObjTypeInference.cpp.

{
 
    // consult cache
    auto tIt = _valueToAllocOrClsNameSources.find(startValue);
    if (tIt != _valueToAllocOrClsNameSources.end())
    {
        return tIt->second;
    }
 
    // simulate the call stack, the second element indicates whether we should update sources for current value
    FILOWorkList<ValueBoolPair> workList;
    Set<ValueBoolPair> visited;
    workList.push({startValue, false});
    while (!workList.empty())
    {
        auto curPair = workList.pop();
        if (visited.count(curPair)) continue;
        visited.insert(curPair);
        const Value *curValue = curPair.first;
        bool canUpdate = curPair.second;
 
        Set<const Value *> sources;
        auto insertSource = [&sources, &canUpdate](const Value *source)
        {
            if (canUpdate) sources.insert(source);
        };
        auto insertSourcesOrPushWorklist = [this, &sources, &workList, &canUpdate](const auto &pUser)
        {
            auto vIt = _valueToAllocOrClsNameSources.find(pUser);
            if (canUpdate)
            {
                if (vIt != _valueToAllocOrClsNameSources.end() && !vIt->second.empty())
                {
                    sources.insert(vIt->second.begin(), vIt->second.end());
                }
            }
            else
            {
                if (vIt == _valueToAllocOrClsNameSources.end()) workList.push({pUser, false});
            }
        };
 
        if (!canUpdate && !_valueToAllocOrClsNameSources.count(curValue))
        {
            workList.push({curValue, true});
        }
 
        // If current value is an instruction inside a constructor/destructor/template, use it as a source
        if (const auto *inst = SVFUtil::dyn_cast<Instruction>(curValue))
        {
            if (const auto *parent = inst->getFunction())
            {
                if (isClsNameSource(parent)) insertSource(parent);
            }
        }
 
        // If the current value is an object (global, heap, stack, etc) or name source (constructor/destructor,
        // a C++ dynamic cast, or a template function), use it as a source
        if (isAlloc(curValue) || isClsNameSource(curValue))
        {
            insertSource(curValue);
        }
 
        // Explore the current value further depending on the type of the value; use cached values if possible
        if (const auto *getElementPtrInst = SVFUtil::dyn_cast<GetElementPtrInst>(curValue))
        {
            insertSourcesOrPushWorklist(getElementPtrInst->getPointerOperand());
        }
        else if (const auto *bitCastInst = SVFUtil::dyn_cast<BitCastInst>(curValue))
        {
            insertSourcesOrPushWorklist(bitCastInst->getOperand(0));
        }
        else if (const auto *phiNode = SVFUtil::dyn_cast<PHINode>(curValue))
        {
            for (const auto *op : phiNode->operand_values())
            {
                insertSourcesOrPushWorklist(op);
            }
        }
        else if (const auto *loadInst = SVFUtil::dyn_cast<LoadInst>(curValue))
        {
            for (const auto *user : loadInst->getPointerOperand()->users())
            {
                if (const auto *storeInst = SVFUtil::dyn_cast<StoreInst>(user))
                {
                    if (storeInst->getPointerOperand() == loadInst->getPointerOperand())
                    {
                        insertSourcesOrPushWorklist(storeInst->getValueOperand());
                    }
                }
            }
        }
        else if (const auto *argument = SVFUtil::dyn_cast<Argument>(curValue))
        {
            for (const auto *user: argument->getParent()->users())
            {
                if (const auto *callBase = SVFUtil::dyn_cast<CallBase>(user))
                {
                    // skip function as parameter
                    // e.g., call void @foo(%struct.ssl_ctx_st* %9, i32 (i8*, i32, i32, i8*)* @passwd_callback)
                    if (callBase->getCalledFunction() != argument->getParent()) continue;
                    u32_t pos = argument->getParent()->isVarArg() ? 0 : argument->getArgNo();
                    insertSourcesOrPushWorklist(callBase->getArgOperand(pos));
                }
            }
        }
        else if (const auto *callBase = SVFUtil::dyn_cast<CallBase>(curValue))
        {
            ABORT_IFNOT(!callBase->doesNotReturn(), "callbase does not return:" + dumpValueAndDbgInfo(callBase));
            if (const auto *callee = callBase->getCalledFunction())
            {
                if (!callee->isDeclaration())
                {
                    LLVMModuleSet* llvmmodule = LLVMModuleSet::getLLVMModuleSet();
                    const BasicBlock* exitBB = llvmmodule->getFunExitBB(callee);
                    assert (exitBB && "exit bb is not a basic block?");
                    const Value *pValue = &exitBB->back();
                    const auto *retInst = SVFUtil::dyn_cast<ReturnInst>(pValue);
                    ABORT_IFNOT(retInst && retInst->getReturnValue(), "not return inst?");
                    insertSourcesOrPushWorklist(retInst->getReturnValue());
                }
            }
        }
 
        // If updating is allowed; store the gathered sources as sources for the current value in the cache
        if (canUpdate)
        {
            _valueToAllocOrClsNameSources[curValue] = sources;
        }
    }
 
    return _valueToAllocOrClsNameSources[startValue];
}

defaultType()

const Type * ObjTypeInference::defaultType

(

const Value *

val

)

default type

Definition at line 114 of file ObjTypeInference.cpp.

{
    ABORT_IFNOT(val, "val cannot be null");
    // heap has a default type of 8-bit integer type
    if (SVFUtil::isa<Instruction>(val) && LLVMUtil::isHeapAllocExtCallViaRet(
                SVFUtil::cast<Instruction>(val)))
        return int8Type();
    // otherwise we return a pointer type in the default address space
    return ptrType();
}

fwFindClsNameSources()

Set< const CallBase * > & ObjTypeInference::fwFindClsNameSources ( const Value *  startValue )

protected

forward find class name sources starting from an allocation

Definition at line 961 of file ObjTypeInference.cpp.

{
    assert(startValue && "startValue was null?");
 
    // consult cache
    auto tIt = _objToClsNameSources.find(startValue);
    if (tIt != _objToClsNameSources.end())
    {
        return tIt->second;
    }
 
    Set<const CallBase *> sources;
 
    // Lambda for adding a callee to the sources iff it is a constructor/destructor/template/dyncast
    auto inferViaCppCall = [&sources](const CallBase *caller)
    {
        if (!caller) return;
        if (isClsNameSource(caller)) sources.insert(caller);
    };
 
    // Find all calls of starting val (or through cast); add as potential source iff applicable
    for (const auto *user : startValue->users())
    {
        if (const auto *caller = SVFUtil::dyn_cast<CallBase>(user))
        {
            inferViaCppCall(caller);
        }
        else if (const auto *bitcast = SVFUtil::dyn_cast<BitCastInst>(user))
        {
            for (const auto *cast_user : bitcast->users())
            {
                if (const auto *caller = SVFUtil::dyn_cast<CallBase>(cast_user))
                {
                    inferViaCppCall(caller);
                }
            }
        }
    }
 
    // Store sources in cache for starting value & return the found sources
    return _objToClsNameSources[startValue] = SVFUtil::move(sources);
}

fwInferObjType()

const Type * ObjTypeInference::fwInferObjType ( const Value *  var )

private

forward infer the type of the object pointed by var

forward infer the type of the object pointed by var

Parameters

var

Definition at line 205 of file ObjTypeInference.cpp.

{
    if (const AllocaInst *allocaInst = SVFUtil::dyn_cast<AllocaInst>(var))
    {
        // stack object
        return infersiteToType(allocaInst);
    }
    else if (const GlobalValue *global = SVFUtil::dyn_cast<GlobalValue>(var))
    {
        // global object
        return infersiteToType(global);
    }
    else
    {
        // for heap or static object, we forward infer its type
 
        // consult cache
        auto tIt = _valueToType.find(var);
        if (tIt != _valueToType.end())
        {
            return tIt->second ? tIt->second : defaultType(var);
        }
 
        // simulate the call stack, the second element indicates whether we should update valueTypes for current value
        FILOWorkList<ValueBoolPair> workList;
        Set<ValueBoolPair> visited;
        workList.push({var, false});
 
        while (!workList.empty())
        {
            auto curPair = workList.pop();
            if (visited.count(curPair))
                continue;
            visited.insert(curPair);
            const Value* curValue = curPair.first;
            bool canUpdate = curPair.second;
            Set<const Value*> infersites;
 
            auto insertInferSite = [&infersites,
                                    &canUpdate](const Value* infersite)
            {
                if (canUpdate)
                    infersites.insert(infersite);
            };
            auto insertInferSitesOrPushWorklist =
                [this, &infersites, &workList, &canUpdate](const auto& pUser)
            {
                auto vIt = _valueToInferSites.find(pUser);
                if (canUpdate)
                {
                    if (vIt != _valueToInferSites.end())
                    {
                        infersites.insert(vIt->second.begin(),
                                          vIt->second.end());
                    }
                }
                else
                {
                    if (vIt == _valueToInferSites.end())
                        workList.push({pUser, false});
                }
            };
            if (!canUpdate && !_valueToInferSites.count(curValue))
            {
                workList.push({curValue, true});
            }
            if (const auto* gepInst =
                        SVFUtil::dyn_cast<GetElementPtrInst>(curValue))
                insertInferSite(gepInst);
            for (const auto it : curValue->users())
            {
                if (const auto* loadInst = SVFUtil::dyn_cast<LoadInst>(it))
                {
                    /*
                     * infer based on load, e.g.,
                     %call = call i8* malloc()
                     %1 = bitcast i8* %call to %struct.MyStruct*
                     %q = load %struct.MyStruct, %struct.MyStruct* %1
                     */
                    insertInferSite(loadInst);
                }
                else if (const auto* storeInst =
                             SVFUtil::dyn_cast<StoreInst>(it))
                {
                    if (storeInst->getPointerOperand() == curValue)
                    {
                        /*
                         * infer based on store (pointer operand), e.g.,
                         %call = call i8* malloc()
                         %1 = bitcast i8* %call to %struct.MyStruct*
                         store %struct.MyStruct .., %struct.MyStruct* %1
                         */
                        insertInferSite(storeInst);
                    }
                    else
                    {
                        for (const auto nit :
                                storeInst->getPointerOperand()->users())
                        {
                            /*
                             * propagate across store (value operand) and load
                             %call = call i8* malloc()
                             store i8* %call, i8** %p
                             %q = load i8*, i8** %p
                             ..infer based on %q..
                            */
                            if (SVFUtil::isa<LoadInst>(nit))
                                insertInferSitesOrPushWorklist(nit);
                        }
                        /*
                        * infer based on store (value operand) <- gep (result element)
                         */
                        if (const auto* gepInst =
                                    SVFUtil::dyn_cast<GetElementPtrInst>(
                                        storeInst->getPointerOperand()))
                        {
                            /*
                              %call1 = call i8* @TYPE_MALLOC(i32 noundef 16, i32
                              noundef 2), !dbg !39 %2 = bitcast i8* %call1 to
                              %struct.MyStruct*, !dbg !41 %3 = load
                              %struct.MyStruct*, %struct.MyStruct** %p, align 8,
                              !dbg !42 %next = getelementptr inbounds
                              %struct.MyStruct, %struct.MyStruct* %3, i32 0, i32
                              1, !dbg !43 store %struct.MyStruct* %2,
                              %struct.MyStruct** %next, align 8, !dbg !44 %5 =
                              load %struct.MyStruct*, %struct.MyStruct** %p,
                              align 8, !dbg !48 %next3 = getelementptr inbounds
                              %struct.MyStruct, %struct.MyStruct* %5, i32 0, i32
                              1, !dbg !49 %6 = load %struct.MyStruct*,
                              %struct.MyStruct** %next3, align 8, !dbg !49 infer
                              site -> %f1 = getelementptr inbounds
                              %struct.MyStruct, %struct.MyStruct* %6, i32 0, i32
                              0, !dbg !50
                             */
                            const Value* gepBase = gepInst->getPointerOperand();
                            if (const auto* load =
                                        SVFUtil::dyn_cast<LoadInst>(gepBase))
                            {
                                for (const auto loadUse :
                                        load->getPointerOperand()->users())
                                {
                                    if (loadUse == load ||
                                            !SVFUtil::isa<LoadInst>(loadUse))
                                        continue;
                                    for (const auto gepUse : loadUse->users())
                                    {
                                        if (!SVFUtil::isa<GetElementPtrInst>(
                                                    gepUse))
                                            continue;
                                        for (const auto loadUse2 :
                                                gepUse->users())
                                        {
                                            if (SVFUtil::isa<LoadInst>(
                                                        loadUse2))
                                            {
                                                insertInferSitesOrPushWorklist(
                                                    loadUse2);
                                            }
                                        }
                                    }
                                }
                            }
                            else if (const auto* alloc =
                                         SVFUtil::dyn_cast<AllocaInst>(gepBase))
                            {
                                /*
                                  %2 = alloca %struct.ll, align 8
                                  store i32 0, ptr %1, align 4
                                  %3 = call noalias noundef nonnull ptr
                                  @_Znwm(i64 noundef 16) #2 %4 = getelementptr
                                  inbounds %struct.ll, ptr %2, i32 0, i32 1
                                  store ptr %3, ptr %4, align 8
                                  %5 = getelementptr inbounds %struct.ll, ptr
                                  %2, i32 0, i32 1 %6 = load ptr, ptr %5, align
                                  8 %7 = getelementptr inbounds %struct.ll, ptr
                                  %6, i32 0, i32 0
                                 */
                                for (const auto gepUse : alloc->users())
                                {
                                    if (!SVFUtil::isa<GetElementPtrInst>(
                                                gepUse))
                                        continue;
                                    for (const auto loadUse2 : gepUse->users())
                                    {
                                        if (SVFUtil::isa<LoadInst>(loadUse2))
                                        {
                                            insertInferSitesOrPushWorklist(
                                                loadUse2);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
                else if (const auto* gepInst =
                             SVFUtil::dyn_cast<GetElementPtrInst>(it))
                {
                    /*
                     * infer based on gep (pointer operand)
                     %call = call i8* malloc()
                     %1 = bitcast i8* %call to %struct.MyStruct*
                     %next = getelementptr inbounds %struct.MyStruct,
                     %struct.MyStruct* %1, i32 0..
                     */
                    if (gepInst->getPointerOperand() == curValue)
                        insertInferSite(gepInst);
                }
                else if (const auto* bitcast =
                             SVFUtil::dyn_cast<BitCastInst>(it))
                {
                    // continue on bitcast
                    insertInferSitesOrPushWorklist(bitcast);
                }
                else if (const auto* phiNode = SVFUtil::dyn_cast<PHINode>(it))
                {
                    // continue on bitcast
                    insertInferSitesOrPushWorklist(phiNode);
                }
                else if (const auto* retInst =
                             SVFUtil::dyn_cast<ReturnInst>(it))
                {
                    /*
                     * propagate from return to caller
                      Function Attrs: noinline nounwind optnone uwtable
                      define dso_local i8* @malloc_wrapper() #0 !dbg !22 {
                          entry:
                          %call = call i8* @malloc(i32 noundef 16), !dbg !25
                          ret i8* %call, !dbg !26
                     }
                     %call = call i8* @malloc_wrapper()
                     ..infer based on %call..
                    */
                    for (const auto callsite : retInst->getFunction()->users())
                    {
                        if (const auto* callBase =
                                    SVFUtil::dyn_cast<CallBase>(callsite))
                        {
                            // skip function as parameter
                            // e.g., call void @foo(%struct.ssl_ctx_st* %9, i32 (i8*, i32, i32, i8*)* @passwd_callback)
                            if (callBase->getCalledFunction() !=
                                    retInst->getFunction())
                                continue;
                            insertInferSitesOrPushWorklist(callBase);
                        }
                    }
                }
                else if (const auto* callBase = SVFUtil::dyn_cast<CallBase>(it))
                {
                    /*
                     * propagate from callsite to callee
                      %call = call i8* @malloc(i32 noundef 16)
                      %0 = bitcast i8* %call to %struct.Node*, !dbg !43
                      call void @foo(%struct.Node* noundef %0), !dbg !45
 
                      define dso_local void @foo(%struct.Node* noundef %param)
                     #0 !dbg !22 {...}
                      ..infer based on the formal param %param..
                     */
                    // skip global function value -> callsite
                    // e.g., def @foo() -> call @foo()
                    // we don't skip function as parameter, e.g., def @foo() -> call @bar(..., @foo)
                    if (SVFUtil::isa<Function>(curValue) &&
                            curValue == callBase->getCalledFunction())
                        continue;
                    // skip indirect call
                    // e.g., %0 = ... -> call %0(...)
                    if (!callBase->hasArgument(curValue))
                        continue;
                    if (Function* calleeFunc = callBase->getCalledFunction())
                    {
                        u32_t pos = getArgPosInCall(callBase, curValue);
                        // for varargs function, we cannot directly get the value-flow between actual and formal args e.g., consider the following vararg function @callee 1: call void @callee(%arg) 2: define dso_local i32 @callee(...) #0 !dbg !17 { 3:  ....... 4:  %5 = load i32, ptr %vaarg.addr, align 4, !dbg !55 5:  .......
                        // 6: }
                        // it is challenging to precisely identify the forward value-flow of %arg (Line 2) because the function definition of callee (Line 2) does not have any formal args related to the actual arg %arg therefore we track all possible instructions like ``load i32, ptr %vaarg.addr''
                        if (calleeFunc->isVarArg())
                        {
                            // conservatively track all var args
                            for (auto& I : instructions(calleeFunc))
                            {
                                if (auto* load =
                                            llvm::dyn_cast<llvm::LoadInst>(&I))
                                {
                                    llvm::Value* loadPointer =
                                        load->getPointerOperand();
                                    if (loadPointer->getName().compare(
                                                "vaarg.addr") == 0)
                                    {
                                        insertInferSitesOrPushWorklist(load);
                                    }
                                }
                            }
                        }
                        else if (!calleeFunc->isDeclaration())
                        {
                            insertInferSitesOrPushWorklist(
                                calleeFunc->getArg(pos));
                        }
                    }
                }
            }
            if (canUpdate)
            {
                Set<const Type*> types;
                std::transform(infersites.begin(), infersites.end(),
                               std::inserter(types, types.begin()),
                               infersiteToType);
                _valueToInferSites[curValue] = SVFUtil::move(infersites);
                _valueToType[curValue] = selectLargestSizedType(types);
            }
        }
        const Type* type = _valueToType[var];
        if (type == nullptr)
        {
            type = defaultType(var);
            WARN_MSG("Using default type, trace ID is " +
                     std::to_string(traceId) + ":" + dumpValueAndDbgInfo(var));
        }
        ABORT_IFNOT(type, "type cannot be a null ptr");
        return type;
    }
}

getArgPosInCall()

u32_t ObjTypeInference::getArgPosInCall	(	const CallBase *	callBase,
		const Value *	arg
	)

Definition at line 703 of file ObjTypeInference.cpp.

{
    assert(callBase->hasArgument(arg) && "callInst does not have argument arg?");
    auto it = std::find(callBase->arg_begin(), callBase->arg_end(), arg);
    assert(it != callBase->arg_end() && "Didn't find argument?");
    return std::distance(callBase->arg_begin(), it);
}

getLLVMCtx()

LLVMContext & ObjTypeInference::getLLVMCtx

(

)

Definition at line 125 of file ObjTypeInference.cpp.

{
    return LLVMModuleSet::getLLVMModuleSet()->getContext();
}

inferObjType()

const Type * ObjTypeInference::inferObjType

(

const Value *

var

)

get or infer the type of the object pointed by the value

get or infer the type of the object pointed by var if the start value is a source (alloc/global, heap, static), call fwInferObjType if not, find allocations and then forward get or infer types

Parameters

val

Definition at line 136 of file ObjTypeInference.cpp.

{
    const Type* res = inferPointsToType(var);
    // infer type by leveraging the type alignment of src and dst in memcpy
    // for example,
    //
    // %tmp = alloca %struct.outer
    // %inner_v = alloca %struct.inner
    // %ptr = getelementptr inbounds %struct.outer, ptr %tmp, i32 0, i32 1, !dbg !38
    // %0 = load ptr, ptr %ptr, align 8, !dbg !38
    // call void @llvm.memcpy.p0.p0.i64(ptr %inner_v, ptr %0, i64 24, i1 false)
    //
    //  It is difficult to infer the type of %0 without deep alias analysis,
    //  but we can infer the obj type of %0 based on that of %inner_v.
    if (res == defaultType(var))
    {
        for (const auto& use: var->users())
        {
            if (const CallBase* cs = SVFUtil::dyn_cast<CallBase>(use))
            {
                if (const Function* calledFun = cs->getCalledFunction())
                    if (LLVMUtil::isMemcpyExtFun(calledFun))
                    {
                        assert(cs->getNumOperands() > 1 && "arguments should be greater than 1");
                        const Value* dst = cs->getArgOperand(0);
                        const Value* src = cs->getArgOperand(1);
                        if(calledFun->getName().find("iconv") != std::string::npos)
                        {
                            if(var == cs->getArgOperand(0))
                                return res;
                            dst = cs->getArgOperand(3), src = cs->getArgOperand(1);
                        }
 
                        if (var == dst) return inferPointsToType(src);
                        else if (var == src) return inferPointsToType(dst);
                        else ABORT_MSG("invalid memcpy call");
                    }
            }
        }
    }
    return res;
}

inferPointsToType()

const Type * ObjTypeInference::inferPointsToType

(

const Value *

var

)

Definition at line 179 of file ObjTypeInference.cpp.

{
    if (isAlloc(var)) return fwInferObjType(var);
    Set<const Value *> &sources = bwfindAllocOfVar(var);
    Set<const Type *> types;
    if (sources.empty())
    {
        // cannot find allocation, try to fw infer starting from var
        types.insert(fwInferObjType(var));
    }
    else
    {
        for (const auto &source: sources)
        {
            types.insert(fwInferObjType(source));
        }
    }
    const Type *largestTy = selectLargestSizedType(types);
    ABORT_IFNOT(largestTy, "return type cannot be null");
    return largestTy;
}

inferThisPtrClsName()

Set< std::string > & ObjTypeInference::inferThisPtrClsName

(

const Value *

thisPtr

)

get or infer the class names of thisptr

get or infer the class names of thisptr; starting from :param:thisPtr, will walk backwards to find all potential sources for the class name. Valid sources include global or stack variables, heap allocations, or C++ dynamic casts/constructors/destructors. If the source site is a global/stack/heap variable, find the corresponding constructor/destructor to extract the class' name from (since the type of the variable is not reliable but the demangled name is)

Parameters

thisPtr

Returns

a set of all possible type names that :param:thisPtr could point to

Definition at line 753 of file ObjTypeInference.cpp.

{
    auto it = _thisPtrClassNames.find(thisPtr);
    if (it != _thisPtrClassNames.end()) return it->second;
 
    Set<std::string> names;
 
    // Lambda for checking a function is a valid name source & extracting a class name from it
    auto addNamesFromFunc = [&names](const Function *func) -> void
    {
        ABORT_IFNOT(isClsNameSource(func), "Func is invalid class name source: " + dumpValueAndDbgInfo(func));
        for (const auto &name : extractClsNamesFromFunc(func)) names.insert(name);
    };
 
    // Lambda for getting callee & extracting class name for calls to constructors/destructors/template funcs
    auto addNamesFromCall = [&names, &addNamesFromFunc](const CallBase *call) -> void
    {
        ABORT_IFNOT(isClsNameSource(call), "Call is invalid class name source: " + dumpValueAndDbgInfo(call));
 
        const auto *func = call->getCalledFunction();
        if (isDynCast(func)) names.insert(extractClsNameFromDynCast(call));
        else addNamesFromFunc(func);
    };
 
    // Walk backwards to find all valid source sites for the pointer (e.g. stack/global/heap variables)
    for (const auto &val: bwFindAllocOrClsNameSources(thisPtr))
    {
        // A source site is either a constructor/destructor/template function from which the class name can be
        // extracted; a call to a C++ constructor/destructor/template function from which the class name can be
        // extracted; or an allocation site of an object (i.e. a stack/global/heap variable), from which a
        // forward walk can be performed to find calls to C++ constructor/destructor/template functions from
        // which the class' name can then be extracted; skip starting pointer
        if (val == thisPtr) continue;
 
        if (const auto *func = SVFUtil::dyn_cast<Function>(val))
        {
            // Constructor/destructor/template func; extract name from func directly
            addNamesFromFunc(func);
        }
        else if (isClsNameSource(val))
        {
            // Call to constructor/destructor/template func; get callee; extract name from callee
            ABORT_IFNOT(SVFUtil::isa<CallBase>(val), "Call source site is not a callbase: " + dumpValueAndDbgInfo(val));
            addNamesFromCall(SVFUtil::cast<CallBase>(val));
        }
        else if (isAlloc(val))
        {
            // Stack/global/heap allocation site; walk forward; find constructor/destructor/template calls
            ABORT_IFNOT((SVFUtil::isa<AllocaInst, CallBase, GlobalVariable>(val)),
                        "Alloc site source is not a stack/heap/global variable: " + dumpValueAndDbgInfo(val));
            for (const auto *src : fwFindClsNameSources(val))
            {
                if (const auto *func = SVFUtil::dyn_cast<Function>(src)) addNamesFromFunc(func);
                else if (const auto *call = SVFUtil::dyn_cast<CallBase>(src)) addNamesFromCall(call);
                else ABORT_MSG("Source site from forward walk is invalid: " + dumpValueAndDbgInfo(src));
            }
        }
        else
        {
            ERR_MSG("Unsupported source type found:" + dumpValueAndDbgInfo(val));
        }
    }
 
    return _thisPtrClassNames[thisPtr] = names;
}

int8Type()

const IntegerType * SVF::ObjTypeInference::int8Type ( )

inline

int8 type

Definition at line 89 of file ObjTypeInference.h.

    {
        return Type::getInt8Ty(getLLVMCtx());
    }

isAlloc()

bool ObjTypeInference::isAlloc ( const SVF::Value *  val )

private

is allocation (stack, static, heap)

Definition at line 655 of file ObjTypeInference.cpp.

{
    return LLVMUtil::isObject(val);
}

objTyToNumFields()

u32_t ObjTypeInference::objTyToNumFields

(

const Type *

objTy

)

For an C++ class, it can have variant elements depending on the vtable size, Hence we only handle non-cpp-class object, the type of the cpp class is treated as default PointerType

Definition at line 728 of file ObjTypeInference.cpp.

{
    u32_t num = Options::MaxFieldLimit();
    if (SVFUtil::isa<ArrayType>(objTy))
        num = getNumOfElements(objTy);
    else if (const auto *st = SVFUtil::dyn_cast<StructType>(objTy))
    {
        if (!classTyHasVTable(st))
            num = getNumOfElements(st);
    }
    return num;
}

ptrType()

const Type * SVF::ObjTypeInference::ptrType ( )

inline

pointer type

Definition at line 83 of file ObjTypeInference.h.

    {
        return PointerType::getUnqual(getLLVMCtx());
    }

selectLargestSizedType()

const Type * ObjTypeInference::selectLargestSizedType

(

Set< const Type * > &

objTys

)

select the largest (conservative) type from all types

Definition at line 712 of file ObjTypeInference.cpp.

{
    if (objTys.empty()) return nullptr;
    // map type size to types from with key in descending order
    OrderedMap<u32_t, OrderedSet<const Type *>, std::greater<int>> typeSzToTypes;
    for (const Type *ty: objTys)
    {
        typeSzToTypes[objTyToNumFields(ty)].insert(ty);
    }
    assert(!typeSzToTypes.empty() && "typeSzToTypes cannot be empty");
    OrderedSet<const Type *> largestTypes;
    std::tie(std::ignore, largestTypes) = *typeSzToTypes.begin();
    assert(!largestTypes.empty() && "largest element cannot be empty");
    return *largestTypes.begin();
}

typeSizeDiffTest()

void ObjTypeInference::typeSizeDiffTest	(	const PointerType *	oPTy,
		const Type *	iTy,
		const Value *	val
	)

Definition at line 689 of file ObjTypeInference.cpp.

{
#if TYPE_DEBUG
    Type *oTy = getPtrElementType(oPTy);
    u32_t iTyNum = objTyToNumFields(iTy);
    if (getNumOfElements(oTy) > iTyNum)
    {
        ERR_MSG("original type is:" + dumpType(oTy));
        ERR_MSG("infered type is:" + dumpType(iTy));
        ABORT_MSG("wrong type, trace ID is " + std::to_string(traceId) + ":" + dumpValueAndDbgInfo(val));
    }
#endif
}

validateTypeCheck()

void ObjTypeInference::validateTypeCheck

(

const CallBase *

cs

)

validate type inference

validate type inference

Parameters

cs	: stub malloc function with element number label

Definition at line 664 of file ObjTypeInference.cpp.

{
    if (const Function *func = cs->getCalledFunction())
    {
        if (func->getName().find(TYPEMALLOC) != std::string::npos)
        {
            const Type *objType = fwInferObjType(cs);
            const auto *pInt =
                SVFUtil::dyn_cast<llvm::ConstantInt>(cs->getOperand(1));
            assert(pInt && "the second argument is a integer");
            u32_t iTyNum = objTyToNumFields(objType);
            if (iTyNum >= LLVMUtil::getIntegerValue(pInt).second)
                SVFUtil::outs() << SVFUtil::sucMsg("\t SUCCESS :") << dumpValueAndDbgInfo(cs)
                                << SVFUtil::pasMsg(" TYPE: ")
                                << dumpType(objType) << "\n";
            else
            {
                SVFUtil::errs() << SVFUtil::errMsg("\t FAILURE :") << ":" << dumpValueAndDbgInfo(cs) << " TYPE: "
                                << dumpType(objType) << "\n";
                abort();
            }
        }
    }
}

Member Data Documentation

_objToClsNameSources

ObjToClsNameSources SVF::ObjTypeInference::_objToClsNameSources

private

Definition at line 59 of file ObjTypeInference.h.

_thisPtrClassNames

ValueToClassNames SVF::ObjTypeInference::_thisPtrClassNames

private

Definition at line 57 of file ObjTypeInference.h.

_valueToAllocOrClsNameSources

ValueToSources SVF::ObjTypeInference::_valueToAllocOrClsNameSources

private

Definition at line 58 of file ObjTypeInference.h.

_valueToAllocs

ValueToSources SVF::ObjTypeInference::_valueToAllocs

private

Definition at line 56 of file ObjTypeInference.h.

_valueToInferSites

ValueToInferSites SVF::ObjTypeInference::_valueToInferSites

private

Definition at line 54 of file ObjTypeInference.h.

_valueToType

ValueToType SVF::ObjTypeInference::_valueToType

private

Definition at line 55 of file ObjTypeInference.h.

---

The documentation for this class was generated from the following files:

• /home/runner/work/SVF/SVF/svf-llvm/include/SVF-LLVM/ObjTypeInference.h
• /home/runner/work/SVF/SVF/svf-llvm/lib/ObjTypeInference.cpp