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1) rename staticDetermined -> ConstantOffset
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2) fix a bug in IntervalValue compare Op
3) remove ConstantOffset bool flag. Instead, if byteSize != 0, it is signal of constant offset. If byteSize = 0, it can be zero byte size or non-const offset.
4) add analyzeHeapAllocByteSize(const Value*), which accepts a CallInst like (malloc/calloc/..) and analyze the allocation byte Size of heap function
5) remove the hard code (99999) of maxByteLimit in SVFIR2ItvExeState::getBytefromGepTypePair, and replace it with Options::MaxFieldLimit()
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jiawei.wang committed Nov 26, 2023
1 parent 1d25a01 commit d36fd62
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Showing 7 changed files with 178 additions and 162 deletions.
3 changes: 3 additions & 0 deletions svf-llvm/include/SVF-LLVM/SymbolTableBuilder.h
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Original file line number Diff line number Diff line change
Expand Up @@ -94,6 +94,9 @@ class SymbolTableBuilder
/// Analyse types of heap and static objects
void analyzeStaticObjType(ObjTypeInfo* typeinfo, const Value* val);

/// Analyze byte size of heap alloc function (e.g. malloc/calloc/...)
u32_t analyzeHeapAllocByteSize(const Value* val);

///Get a reference to the components of struct_info.
/// Number of flattened elements of an array or struct
u32_t getNumOfFlattenElements(const Type* T);
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127 changes: 73 additions & 54 deletions svf-llvm/lib/SymbolTableBuilder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -669,6 +669,64 @@ void SymbolTableBuilder::analyzeObjType(ObjTypeInfo* typeinfo, const Value* val)
typeinfo->setFlag(ObjTypeInfo::HASPTR_OBJ);
}

/*!
* Analyze byte size of heap alloc function (e.g. malloc/calloc/...)
*/
u32_t SymbolTableBuilder::analyzeHeapAllocByteSize(const Value* val) {
if (const llvm::CallInst* callInst = llvm::dyn_cast<llvm::CallInst>(val))
{
if (const llvm::Function* calledFunction = callInst->getCalledFunction()) {
const SVFFunction* svfFunction = LLVMModuleSet::getLLVMModuleSet()->getSVFFunction(calledFunction);
std::vector<const Value*> args;
// Heap alloc functions have annoation like "AllocSize:Arg1"
for (std::string annotation: svfFunction->getAnnotations()) {
if (annotation.find("AllocSize:") != std::string::npos) {
std::string allocSize = annotation.substr(10);
std::stringstream ss(allocSize);
std::string token;
// Analyaze annotation string and attract Arg list
while (std::getline(ss, token, '*')) {
if (token.rfind("Arg", 0) == 0) {
int argIndex;
std::istringstream(token.substr(3)) >> argIndex;
if (argIndex < callInst->getNumOperands() - 1) {
args.push_back(callInst->getArgOperand(argIndex));
}
}
}
}
}
uint64_t product = 1;
if (args.size() > 0)
{
// for annotations like "AllocSize:Arg0*Arg1"
for (const llvm::Value* arg : args)
{
if (const llvm::ConstantInt* constIntArg =
llvm::dyn_cast<llvm::ConstantInt>(arg))
{
// Multiply the constant Value if all Args are const
product *= constIntArg->getZExtValue();
}
else
{
// if Arg list has non-const value, return 0 to indicate it is non const byte size
return 0;
}
}
// If all the Args are const, return product
return product;
}
else {
// for annotations like "AllocSize:UNKNOWN"
return 0;
}
}
}
// if it is not CallInst or CallInst has no CalledFunction, return 0 to indicate it is non const byte size
return 0;
}

/*!
* Analyse types of heap and static objects
*/
Expand Down Expand Up @@ -715,6 +773,8 @@ void SymbolTableBuilder::initTypeInfo(ObjTypeInfo* typeinfo, const Value* val,
{

u32_t elemNum = 1;
// init byteSize = 0, If byteSize is changed in the following process,
// it means that ObjTypeInfo has a Constant Byte Size
u32_t byteSize = 0;
// Global variable
// if val is Function Obj, byteSize is not set
Expand All @@ -725,6 +785,7 @@ void SymbolTableBuilder::initTypeInfo(ObjTypeInfo* typeinfo, const Value* val,
elemNum = getNumOfElements(objTy);
}
/// if val is AllocaInst, byteSize is Type's LLVM ByteSize * ArraySize
/// e.g. alloc i32, 10. byteSize is 4 (i32's size) * 10 (ArraySize) = 40
else if(const AllocaInst* allocaInst = SVFUtil::dyn_cast<AllocaInst>(val))
{
typeinfo->setFlag(ObjTypeInfo::STACK_OBJ);
Expand All @@ -740,11 +801,11 @@ void SymbolTableBuilder::initTypeInfo(ObjTypeInfo* typeinfo, const Value* val,
else
{
elemNum = getNumOfElements(objTy);
byteSize = typeinfo->getType()->getLLVMByteSize();
typeinfo->setStaticDeterminedByteSize(false);
byteSize = 0;
}
}
/// if val is GlobalVar, byteSize is Type's LLVM ByteSize
/// All GlobalVariable must have constant size
else if(SVFUtil::isa<GlobalVariable>(val))
{
typeinfo->setFlag(ObjTypeInfo::GLOBVAR_OBJ);
Expand All @@ -763,56 +824,11 @@ void SymbolTableBuilder::initTypeInfo(ObjTypeInfo* typeinfo, const Value* val,
analyzeHeapObjType(typeinfo,val);
// Heap object, label its field as infinite here
elemNum = typeinfo->getMaxFieldOffsetLimit();
if (const llvm::CallInst* callInst = llvm::dyn_cast<llvm::CallInst>(val))
{
if (const llvm::Function* calledFunction =
callInst->getCalledFunction())
{
std::string functionName = calledFunction->getName().str();
// Check if the function called is 'malloc' and process its argument.
// if arg is constant, set byteSize, otherwise byteSize is not static determined.
if (functionName == "malloc" && callInst->getNumOperands() > 0)
{
if (const llvm::ConstantInt* arg =
llvm::dyn_cast<llvm::ConstantInt>(
callInst->getArgOperand(0)))
{
byteSize = arg->getZExtValue();
}
else {
typeinfo->setStaticDeterminedByteSize(false);
}
}
// Check if the function called is 'calloc' and process its arguments.
// if both arg0 and arg1 is constant, set byteSize,
// otherwise byteSize is not static determined.
else if (functionName == "calloc" &&
callInst->getNumOperands() > 1)
{
if (const llvm::ConstantInt* arg1 =
llvm::dyn_cast<llvm::ConstantInt>(
callInst->getArgOperand(0)))
{
if (const llvm::ConstantInt* arg2 =
llvm::dyn_cast<llvm::ConstantInt>(
callInst->getArgOperand(1)))
{
byteSize = arg1->getZExtValue() * arg2->getZExtValue();
} else {
typeinfo->setStaticDeterminedByteSize(false);
}
} else {
typeinfo->setStaticDeterminedByteSize(false);
}
}
// Other function, let ByteSize be non-static determined.
else
{
typeinfo->setStaticDeterminedByteSize(false);
}
}
}

// analyze heap alloc like (malloc/calloc/...), the alloc functions have
// annotation like "AllocSize:Arg1". Please refer to extapi.c.
// e.g. calloc(4, 10), annotation is "AllocSize:Arg0*Arg1",
// it means byteSize = 4 (Arg0) * 10 (Arg1) = 40
byteSize = analyzeHeapAllocByteSize(val);
}
else if(ArgInProgEntryFunction(val))
{
Expand All @@ -836,9 +852,12 @@ void SymbolTableBuilder::initTypeInfo(ObjTypeInfo* typeinfo, const Value* val,
// Reset maxOffsetLimit if it is over the total fieldNum of this object
if(typeinfo->getMaxFieldOffsetLimit() > elemNum)
typeinfo->setNumOfElements(elemNum);
if(typeinfo->isStaticDeterminedByteSize())
typeinfo->setByteSizeOfObj(byteSize);

// set ByteSize. If ByteSize > 0, this typeinfo has constant type.
// If ByteSize == 0, this typeinfo has 1) zero byte 2) non-const byte size
// If ByteSize>MaxFieldLimit, set MaxFieldLimit to the byteSize;
byteSize = Options::MaxFieldLimit() > byteSize? byteSize: Options::MaxFieldLimit();
typeinfo->setByteSizeOfObj(byteSize);
}

/*!
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