void InstrProfiling::emitUses() {
if (UsedVars.empty())
return;
GlobalVariable *LLVMUsed = M->getGlobalVariable("llvm.used");
std::vector<Constant *> MergedVars;
if (LLVMUsed) {
// Collect the existing members of llvm.used.
ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
for (unsigned I = 0, E = Inits->getNumOperands(); I != E; ++I)
MergedVars.push_back(Inits->getOperand(I));
LLVMUsed->eraseFromParent();
}
Type *i8PTy = Type::getInt8PtrTy(M->getContext());
// Add uses for our data.
for (auto *Value : UsedVars)
MergedVars.push_back(
ConstantExpr::getBitCast(cast<Constant>(Value), i8PTy));
// Recreate llvm.used.
ArrayType *ATy = ArrayType::get(i8PTy, MergedVars.size());
LLVMUsed =
new GlobalVariable(*M, ATy, false, GlobalValue::AppendingLinkage,
ConstantArray::get(ATy, MergedVars), "llvm.used");
LLVMUsed->setSection("llvm.metadata");
}
/// Given a specified llvm.global_ctors list, remove the listed elements.
static void removeGlobalCtors(GlobalVariable *GCL, const BitVector &CtorsToRemove) {
// Filter out the initializer elements to remove.
ConstantArray *OldCA = cast<ConstantArray>(GCL->getInitializer());
SmallVector<Constant *, 10> CAList;
for (unsigned I = 0, E = OldCA->getNumOperands(); I < E; ++I)
if (!CtorsToRemove.test(I))
CAList.push_back(OldCA->getOperand(I));
// Create the new array initializer.
ArrayType *ATy =
ArrayType::get(OldCA->getType()->getElementType(), CAList.size());
Constant *CA = ConstantArray::get(ATy, CAList);
// If we didn't change the number of elements, don't create a new GV.
if (CA->getType() == OldCA->getType()) {
GCL->setInitializer(CA);
return;
}
// Create the new global and insert it next to the existing list.
GlobalVariable *NGV =
new GlobalVariable(CA->getType(), GCL->isConstant(), GCL->getLinkage(),
CA, "", GCL->getThreadLocalMode());
GCL->getParent()->getGlobalList().insert(GCL->getIterator(), NGV);
NGV->takeName(GCL);
// Nuke the old list, replacing any uses with the new one.
if (!GCL->use_empty()) {
Constant *V = NGV;
if (V->getType() != GCL->getType())
V = ConstantExpr::getBitCast(V, GCL->getType());
GCL->replaceAllUsesWith(V);
}
GCL->eraseFromParent();
}
/// runStaticConstructorsDestructors - This method is used to execute all of
/// the static constructors or destructors for a module, depending on the
/// value of isDtors.
void ExecutionEngine::runStaticConstructorsDestructors(Module *module, bool isDtors) {
const char *Name = isDtors ? "llvm.global_dtors" : "llvm.global_ctors";
// Execute global ctors/dtors for each module in the program.
GlobalVariable *GV = module->getNamedGlobal(Name);
// If this global has internal linkage, or if it has a use, then it must be
// an old-style (llvmgcc3) static ctor with __main linked in and in use. If
// this is the case, don't execute any of the global ctors, __main will do
// it.
if (!GV || GV->isDeclaration() || GV->hasLocalLinkage()) return;
// Should be an array of '{ int, void ()* }' structs. The first value is
// the init priority, which we ignore.
ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
if (!InitList) return;
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
if (ConstantStruct *CS =
dyn_cast<ConstantStruct>(InitList->getOperand(i))) {
if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
Constant *FP = CS->getOperand(1);
if (FP->isNullValue())
break; // Found a null terminator, exit.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
if (CE->isCast())
FP = CE->getOperand(0);
if (Function *F = dyn_cast<Function>(FP)) {
// Execute the ctor/dtor function!
runFunction(F, std::vector<GenericValue>());
}
}
}
void ClassHierarchyUtils::findClassHierarchy(Module& M) {
// Extract class hierarchy using std::type_info structures rather than debug
// info. The former works even for when there are anonymous namespaces.
// (for more info, see http://mentorembedded.github.io/cxx-abi/abi.html)
//
// Class names are usually global, except in the case of anonymous namespaces, in which case
// they may be renamed during linking. This renaming is not consistent across type_info and
// vtables. For example, the following are for the same class:
// _ZTIN7content12_GLOBAL__N_115HeaderFlattenerE60908 and
// _ZTVN7content12_GLOBAL__N_115HeaderFlattenerE60906.
//
// (renamed from
// _ZTVN7content12_GLOBAL__N_115HeaderFlattenerE and
// _ZTIN7content12_GLOBAL__N_115HeaderFlattenerE).
//
// VTables give us the corresponding type_info, so we process them first and store
// the VT <-> TI mappings, as this will be useful later.
for (Module::global_iterator I=M.global_begin(), E=M.global_end(); I != E; I++) {
GlobalVariable* VT = &*I;
if (VT->getName().startswith("_ZTV")) {
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "Found vtable: " << VT->getName() << "\n");
if (VT->hasInitializer()) {
ConstantStruct* VTinit = cast<ConstantStruct>(VT->getInitializer());
// all occurrences of a type_info object refer to this class's type_info, so we
// can pick the first array
ConstantArray* VTinitElem = cast<ConstantArray>(VTinit->getOperand(0));
for (int i=0; i<VTinitElem->getNumOperands(); i++) {
// type_info will be the first global variable in the array.
// It's not always at a fixed index so we have to search for it...
// The first one corresponds to the primary vtable, all others
// correspond to secondary vtables. All type_info occurrences will
// be the same.
if (GlobalVariable* TI = dyn_cast<GlobalVariable>(VTinitElem->getOperand(i)->stripPointerCasts())) {
if (typeInfoToVTable.find(TI) != typeInfoToVTable.end()) {
report_fatal_error(TI->getName() + " <-> " + VT->getName() + " mapping already exists!");
}
// Record TI <-> VT mappings, as they will be useful later
typeInfoToVTable[TI] = VT;
vTableToTypeInfo[VT] = TI;
break; // we only need to process the first one
}
}
}
else {
SDEBUG("soaap.util.classhierarchy", 1, dbgs() << "WARNING: VTable " << VT->getName() << " does not have initializer\n");
}
}
}
// Process type_info structures, recording class-hierarchy information and base offsets
for (Module::global_iterator I=M.global_begin(), E=M.global_end(); I != E; I++) {
GlobalVariable* G = &*I;
if (G->getName().startswith("_ZTI")) {
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "Found type_info: " << G->getName() << "\n");
processTypeInfo(G, M);
}
}
SDEBUG("soaap.util.classhierarchy", 3, ppClassHierarchy(classToSubclasses));
}
static void readFuncList(GlobalVariable *Array, std::vector<Constant*> *Funcs) {
if (!Array->hasInitializer())
return;
Constant *Init = Array->getInitializer();
ArrayType *Ty = dyn_cast<ArrayType>(Init->getType());
if (!Ty) {
errs() << "Initializer: " << *Array->getInitializer() << "\n";
report_fatal_error("ExpandCtors: Initializer is not of array type");
}
if (Ty->getNumElements() == 0)
return;
ConstantArray *InitList = dyn_cast<ConstantArray>(Init);
if (!InitList) {
errs() << "Initializer: " << *Array->getInitializer() << "\n";
report_fatal_error("ExpandCtors: Unexpected initializer ConstantExpr");
}
std::vector<FuncArrayEntry> FuncsToSort;
for (unsigned Index = 0; Index < InitList->getNumOperands(); ++Index) {
ConstantStruct *CS = cast<ConstantStruct>(InitList->getOperand(Index));
FuncArrayEntry Entry;
Entry.priority = cast<ConstantInt>(CS->getOperand(0))->getZExtValue();
Entry.func = CS->getOperand(1);
FuncsToSort.push_back(Entry);
}
std::sort(FuncsToSort.begin(), FuncsToSort.end(), compareEntries);
for (std::vector<FuncArrayEntry>::iterator Iter = FuncsToSort.begin();
Iter != FuncsToSort.end();
++Iter) {
Funcs->push_back(Iter->func);
}
}
void InstrProfiling::lowerCoverageData(GlobalVariable *CoverageData) {
CoverageData->setSection(getCoverageSection());
CoverageData->setAlignment(8);
Constant *Init = CoverageData->getInitializer();
// We're expecting { i32, i32, i32, i32, [n x { i8*, i32, i32 }], [m x i8] }
// for some C. If not, the frontend's given us something broken.
assert(Init->getNumOperands() == 6 && "bad number of fields in coverage map");
assert(isa<ConstantArray>(Init->getAggregateElement(4)) &&
"invalid function list in coverage map");
ConstantArray *Records = cast<ConstantArray>(Init->getAggregateElement(4));
for (unsigned I = 0, E = Records->getNumOperands(); I < E; ++I) {
Constant *Record = Records->getOperand(I);
Value *V = const_cast<Value *>(Record->getOperand(0))->stripPointerCasts();
assert(isa<GlobalVariable>(V) && "Missing reference to function name");
GlobalVariable *Name = cast<GlobalVariable>(V);
// If we have region counters for this name, we've already handled it.
auto It = RegionCounters.find(Name);
if (It != RegionCounters.end())
continue;
// Move the name variable to the right section.
Name->setSection(getNameSection());
Name->setAlignment(1);
}
}
void ClassHierarchyUtils::findClassHierarchy(Module& M) {
// extract call hierarchy using std::type_info structures rather
// than debug info. The former works even for when there are anonymous
// namespaces. type_info structs can be obtained from vtable globals.
// (for more info, see http://mentorembedded.github.io/cxx-abi/abi.html)
for (Module::global_iterator I=M.global_begin(), E=M.global_end(); I != E; I++) {
GlobalVariable* G = &*I;
if (G->getName().startswith("_ZTV")) {
if (G->hasInitializer()) {
SDEBUG("soaap.util.classhierarchy", 3, G->dump());
ConstantArray* Ginit = cast<ConstantArray>(G->getInitializer());
// Ginit[1] is the type_info global for this vtable's type
bool typeInfoFound = false;
bool primaryVTable = true;
for (int i=0; i<Ginit->getNumOperands(); i++) {
// typeinfo will be the first global variable in the array.
// It's not always at a fixed index so we have to search for it...
if (GlobalVariable* TI = dyn_cast<GlobalVariable>(Ginit->getOperand(i)->stripPointerCasts())) {
//TI->dump();
typeInfoToVTable[TI] = G;
vTableToTypeInfo[G] = TI;
processTypeInfo(TI); // process TI recursively (it contains refs to super-class TIs)
typeInfoFound = true;
if (primaryVTable) {
primaryVTable = false;
vTableToSecondaryVTableMaps[G][0] = i+1; // i+1 is also the size of the vtable header
}
else {
// offset_to_top is at the previous index
ConstantExpr* offsetValCast = cast<ConstantExpr>(Ginit->getOperand(i-1)->stripPointerCasts());
ConstantInt* offsetVal = cast<ConstantInt>(offsetValCast->getOperand(0));
int offsetToTop = offsetVal->getSExtValue();
if (offsetToTop > 0) {
dbgs() << "ERROR: offsetToTop is positive!\n";
G->dump();
}
else {
offsetToTop *= -1;
}
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "offsetToTop: " << offsetToTop << "\n");
vTableToSecondaryVTableMaps[G][offsetToTop] = i+1;
}
}
}
if (!typeInfoFound) {
dbgs() << "ERROR: vtable initializer is not a global variable...\n";
dbgs() << *G << " = " << *Ginit << "\n";
}
}
}
}
SDEBUG("soaap.util.classhierarchy", 3, ppClassHierarchy(classToSubclasses));
}
bool SDFix::fixDestructors2() {
bool replaced = false;
for (GlobalVariable& gv : module->getGlobalList()) {
if (! sd_isVtableName_ref(gv.getName()))
continue;
else if (! gv.hasInitializer())
continue;
Constant* init = gv.getInitializer();
assert(init);
ConstantArray* vtable = dyn_cast<ConstantArray>(init);
assert(vtable);
for(unsigned i=0; i<vtable->getNumOperands(); i++) {
Constant* destructor = sd_getDestructorFunction(vtable->getOperand(i));
if (destructor == NULL)
continue;
// get the type from its name
unsigned s = destructor->getName().size();
char type = destructor->getName()[s-3];
assert('0' <= type && type <= '2');
unsigned typeInt = type - '0';
DestructorInfo di(destructor, i);
if(di.isDefined)
continue;
// this only handles the 1 -> 2 conversion
assert(typeInt == 1);
Function* f1 = di.getFunction();
assert(f1);
std::string gv2Name = f1->getName();
unsigned l = gv2Name.length();
gv2Name = gv2Name.replace(l-3, 1, "2");
Function* f2 = module->getFunction(gv2Name);
assert(f2 && ! f2->isDeclaration());
sd_print("Replacing %s with %s inside %s\n",
f1->getName().data(),
gv2Name.c_str(),
gv.getName().data());
f1->replaceAllUsesWith(f2);
replaced = true;
}
}
return replaced;
}
/// SplitStaticCtorDtor - A module was recently split into two parts, M1/M2, and
/// M1 has all of the global variables. If M2 contains any functions that are
/// static ctors/dtors, we need to add an llvm.global_[cd]tors global to M2, and
/// prune appropriate entries out of M1s list.
static void SplitStaticCtorDtor(const char *GlobalName, Module *M1, Module *M2,
DenseMap<const Value*, Value*> ValueMap) {
GlobalVariable *GV = M1->getNamedGlobal(GlobalName);
if (!GV || GV->isDeclaration() || GV->hasLocalLinkage() ||
!GV->use_empty()) return;
std::vector<std::pair<Function*, int> > M1Tors, M2Tors;
ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
if (!InitList) return;
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
if (CS->getOperand(1)->isNullValue())
break; // Found a null terminator, stop here.
ConstantInt *CI = dyn_cast<ConstantInt>(CS->getOperand(0));
int Priority = CI ? CI->getSExtValue() : 0;
Constant *FP = CS->getOperand(1);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
if (CE->isCast())
FP = CE->getOperand(0);
if (Function *F = dyn_cast<Function>(FP)) {
if (!F->isDeclaration())
M1Tors.push_back(std::make_pair(F, Priority));
else {
// Map to M2's version of the function.
F = cast<Function>(ValueMap[F]);
M2Tors.push_back(std::make_pair(F, Priority));
}
}
}
}
GV->eraseFromParent();
if (!M1Tors.empty()) {
Constant *M1Init = GetTorInit(M1Tors);
new GlobalVariable(*M1, M1Init->getType(), false,
GlobalValue::AppendingLinkage,
M1Init, GlobalName);
}
GV = M2->getNamedGlobal(GlobalName);
assert(GV && "Not a clone of M1?");
assert(GV->use_empty() && "llvm.ctors shouldn't have uses!");
GV->eraseFromParent();
if (!M2Tors.empty()) {
Constant *M2Init = GetTorInit(M2Tors);
new GlobalVariable(*M2, M2Init->getType(), false,
GlobalValue::AppendingLinkage,
M2Init, GlobalName);
}
}
static void findUsedValues(GlobalVariable *LLVMUsed,
SmallPtrSetImpl<GlobalValue*> &UsedValues) {
if (!LLVMUsed) return;
ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
if (GlobalValue *GV =
dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
UsedValues.insert(GV);
}
/// Find values that are marked as llvm.used.
static void FindUsedValues(GlobalVariable *LLVMUsed,
SmallPtrSet<const GlobalValue*, 8> &UsedValues) {
if (LLVMUsed == 0) return;
ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i) {
Value *Operand = Inits->getOperand(i)->stripPointerCastsNoFollowAliases();
GlobalValue *GV = cast<GlobalValue>(Operand);
UsedValues.insert(GV);
}
}
/// Given a llvm.global_ctors list that we can understand,
/// return a list of the functions and null terminator as a vector.
static std::vector<Function *> parseGlobalCtors(GlobalVariable *GV) {
if (GV->getInitializer()->isNullValue())
return std::vector<Function *>();
ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
std::vector<Function *> Result;
Result.reserve(CA->getNumOperands());
for (auto &V : CA->operands()) {
ConstantStruct *CS = cast<ConstantStruct>(V);
Result.push_back(dyn_cast<Function>(CS->getOperand(1)));
}
return Result;
}
static std::vector<Function*> parseGlobalCtors(GlobalVariable *GV) {
if (GV->getInitializer()->isNullValue())
return std::vector<Function *>();
ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
std::vector<Function *> Result;
Result.reserve(CA->getNumOperands());
for (User::op_iterator i = CA->op_begin(), e = CA->op_end(); i != e; ++i) {
ConstantStruct *CS = cast<ConstantStruct>(*i);
Result.push_back(dyn_cast<Function>(CS->getOperand(1)));
}
return Result;
}
/// EmitLLVMUsedList - For targets that define a TAI::UsedDirective, mark each
/// global in the specified llvm.used list as being used with this directive.
void AsmPrinter::EmitLLVMUsedList(Constant *List) {
const char *Directive = TAI->getUsedDirective();
// Should be an array of 'sbyte*'.
ConstantArray *InitList = dyn_cast<ConstantArray>(List);
if (InitList == 0) return;
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
O << Directive;
EmitConstantValueOnly(InitList->getOperand(i));
O << "\n";
}
}
void InstrProfiling::lowerCoverageData(GlobalVariable *CoverageNamesVar) {
ConstantArray *Names =
cast<ConstantArray>(CoverageNamesVar->getInitializer());
for (unsigned I = 0, E = Names->getNumOperands(); I < E; ++I) {
Constant *NC = Names->getOperand(I);
Value *V = NC->stripPointerCasts();
assert(isa<GlobalVariable>(V) && "Missing reference to function name");
GlobalVariable *Name = cast<GlobalVariable>(V);
Name->setLinkage(GlobalValue::PrivateLinkage);
ReferencedNames.push_back(Name);
}
}
/// EmitXXStructorList - Emit the ctor or dtor list. This just emits out the
/// function pointers, ignoring the init priority.
void ELFWriter::EmitXXStructorList(Constant *List, ELFSection &Xtor) {
// Should be an array of '{ int, void ()* }' structs. The first value is the
// init priority, which we ignore.
if (!isa<ConstantArray>(List)) return;
ConstantArray *InitList = cast<ConstantArray>(List);
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
if (CS->getOperand(1)->isNullValue())
return; // Found a null terminator, exit printing.
// Emit the function pointer.
EmitGlobalConstant(CS->getOperand(1), Xtor);
}
}
/// AnalyzeModule - Scan the module for global debug information.
///
void MachineModuleInfo::AnalyzeModule(Module &M) {
// Insert functions in the llvm.used array (but not llvm.compiler.used) into
// UsedFunctions.
GlobalVariable *GV = M.getGlobalVariable("llvm.used");
if (!GV || !GV->hasInitializer()) return;
// Should be an array of 'i8*'.
ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
if (InitList == 0) return;
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
if (Function *F =
dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
UsedFunctions.insert(F);
}
// what a hack
static Function *getStubFunctionForCtorList(Module *m,
GlobalVariable *gv,
std::string name) {
assert(!gv->isDeclaration() && !gv->hasInternalLinkage() &&
"do not support old LLVM style constructor/destructor lists");
std::vector<Type *> nullary;
Function *fn = Function::Create(FunctionType::get(Type::getVoidTy(m->getContext()),
nullary, false),
GlobalVariable::InternalLinkage,
name,
m);
BasicBlock *bb = BasicBlock::Create(m->getContext(), "entry", fn);
// From lli:
// Should be an array of '{ int, void ()* }' structs. The first value is
// the init priority, which we ignore.
ConstantArray *arr = dyn_cast<ConstantArray>(gv->getInitializer());
if (arr) {
for (unsigned i=0; i<arr->getNumOperands(); i++) {
ConstantStruct *cs = cast<ConstantStruct>(arr->getOperand(i));
#if LLVM_VERSION_CODE >= LLVM_VERSION(3, 5)
// There is a third *optional* element in global_ctor elements (``i8
// @data``).
assert((cs->getNumOperands() == 2 || cs->getNumOperands() == 3) &&
"unexpected element in ctor initializer list");
#else
assert(cs->getNumOperands()==2 && "unexpected element in ctor initializer list");
#endif
Constant *fp = cs->getOperand(1);
if (!fp->isNullValue()) {
if (llvm::ConstantExpr *ce = dyn_cast<llvm::ConstantExpr>(fp))
fp = ce->getOperand(0);
if (Function *f = dyn_cast<Function>(fp)) {
CallInst::Create(f, "", bb);
} else {
assert(0 && "unable to get function pointer from ctor initializer list");
}
}
}
}
ReturnInst::Create(m->getContext(), bb);
return fn;
}
/// VisitGlobalInit - The specified lattice value corresponds to a field (or
/// several) in the specified global. Merge all of the overlapping initializer
/// values into LV (up-to and until it becomes overdefined).
///
static bool VisitGlobalInit(LatticeValue *LV, Constant *Init,
unsigned FieldOffset) {
const TargetData &TD = LV->getParentGraph().getTargetData();
if (Init->isNullValue())
return LV->visitGlobalInit(Constant::getNullValue(LV->getFieldType()));
if (isa<UndefValue>(Init))
return LV->visitGlobalInit(UndefValue::get(LV->getFieldType()));
if (LV->getNode()->isArray() &&
TD.getTypeSize(Init->getType()) > LV->getNode()->getSize()) {
ConstantArray *CA = cast<ConstantArray>(Init);
for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
if (VisitGlobalInit(LV, CA->getOperand(i), FieldOffset))
return true;
return false;
}
NextStep: // Manual tail recursion
if (Init->isNullValue())
return LV->visitGlobalInit(Constant::getNullValue(LV->getFieldType()));
if (isa<UndefValue>(Init))
return LV->visitGlobalInit(UndefValue::get(LV->getFieldType()));
if (Init->getType()->isFirstClassType()) {
assert(FieldOffset == 0 && "GV Init mismatch!");
return LV->visitGlobalInit(Init);
}
if (const StructType *STy = dyn_cast<StructType>(Init->getType())) {
const StructLayout *SL = TD.getStructLayout(STy);
unsigned Field = SL->getElementContainingOffset(FieldOffset);
FieldOffset -= SL->MemberOffsets[Field];
Init = cast<ConstantStruct>(Init)->getOperand(Field);
goto NextStep;
} else if (const ArrayType *ATy = dyn_cast<ArrayType>(Init->getType())) {
unsigned ElSz = TD.getTypeSize(ATy->getElementType());
unsigned Idx = FieldOffset / ElSz;
FieldOffset -= Idx*ElSz;
Init = cast<ConstantArray>(Init)->getOperand(Idx);
goto NextStep;
} else {
assert(0 && "Unexpected initializer type!");
return true;
}
}
bool CheckInserter::doFinalization(Module &M) {
// We couldn't directly add an element to a constant array, because doing so
// changes the type of the constant array.
// element type of llvm.global_ctors
StructType *ST = StructType::get(IntType,
PointerType::getUnqual(InitFiniType),
NULL); // end with null
// Move all existing elements of <GlobalName> to <Constants>.
vector<Constant *> Constants;
if (GlobalVariable *GlobalCtors = M.getNamedGlobal("llvm.global_ctors")) {
ConstantArray *CA = cast<ConstantArray>(GlobalCtors->getInitializer());
for (unsigned j = 0; j < CA->getNumOperands(); ++j) {
ConstantStruct *CS = cast<ConstantStruct>(CA->getOperand(j));
assert(CS->getType() == ST);
// Assume nobody is using the highest priority, so that <F> will be the
// first to run as a ctor.
assert(!cast<ConstantInt>(CS->getOperand(0))->isMinValue(true));
Constants.push_back(CS);
}
GlobalCtors->eraseFromParent();
}
// Add <F> with the highest priority.
Constants.push_back(ConstantStruct::get(ST,
ConstantInt::get(IntType, INT_MIN),
EnterProcess,
NULL));
// Create the new llvm.global_ctors.
ArrayType *ArrType = ArrayType::get(ST, Constants.size());
new GlobalVariable(M,
ArrType,
true,
GlobalValue::AppendingLinkage,
ConstantArray::get(ArrType, Constants),
"llvm.global_ctors");
return true;
}
//
// Method: postOrderInline()
//
// Description:
// This methods does a post order traversal of the call graph and performs
// bottom-up inlining of the DSGraphs.
//
void
BUDataStructures::postOrderInline (Module & M) {
// Variables used for Tarjan SCC-finding algorithm. These are passed into
// the recursive function used to find SCCs.
std::vector<const Function*> Stack;
std::map<const Function*, unsigned> ValMap;
unsigned NextID = 1;
// Do post order traversal on the global ctors. Use this information to update
// the globals graph.
const char *Name = "llvm.global_ctors";
GlobalVariable *GV = M.getNamedGlobal(Name);
if (GV && !(GV->isDeclaration()) && !(GV->hasLocalLinkage())) {
// Should be an array of '{ int, void ()* }' structs. The first value is
// the init priority, which we ignore.
ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
if (InitList) {
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))) {
if (CS->getNumOperands() != 2)
break; // Not array of 2-element structs.
Constant *FP = CS->getOperand(1);
if (FP->isNullValue())
break; // Found a null terminator, exit.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
if (CE->isCast())
FP = CE->getOperand(0);
Function *F = dyn_cast<Function>(FP);
if (F && !F->isDeclaration() && !ValMap.count(F)) {
calculateGraphs(F, Stack, NextID, ValMap);
CloneAuxIntoGlobal(getDSGraph(*F));
}
}
GlobalsGraph->removeTriviallyDeadNodes();
GlobalsGraph->maskIncompleteMarkers();
// Mark external globals incomplete.
GlobalsGraph->markIncompleteNodes(DSGraph::IgnoreGlobals);
GlobalsGraph->computeExternalFlags(DSGraph::DontMarkFormalsExternal);
GlobalsGraph->computeIntPtrFlags();
//
// Create equivalence classes for aliasing globals so that we only need to
// record one global per DSNode.
//
formGlobalECs();
// propogte information calculated
// from the globals graph to the other graphs.
for (Module::iterator F = M.begin(); F != M.end(); ++F) {
if (!(F->isDeclaration())){
DSGraph *Graph = getDSGraph(*F);
cloneGlobalsInto(Graph, DSGraph::DontCloneCallNodes |
DSGraph::DontCloneAuxCallNodes);
Graph->buildCallGraph(callgraph, GlobalFunctionList, filterCallees);
Graph->maskIncompleteMarkers();
Graph->markIncompleteNodes(DSGraph::MarkFormalArgs |
DSGraph::IgnoreGlobals);
Graph->computeExternalFlags(DSGraph::DontMarkFormalsExternal);
Graph->computeIntPtrFlags();
}
}
}
}
//
// Start the post order traversal with the main() function. If there is no
// main() function, don't worry; we'll have a separate traversal for inlining
// graphs for functions not reachable from main().
//
Function *MainFunc = M.getFunction ("main");
if (MainFunc && !MainFunc->isDeclaration()) {
calculateGraphs(MainFunc, Stack, NextID, ValMap);
CloneAuxIntoGlobal(getDSGraph(*MainFunc));
}
//
// Calculate the graphs for any functions that are unreachable from main...
//
for (Function &F : M)
if (!F.isDeclaration() && !ValMap.count(&F)) {
if (MainFunc)
DEBUG(errs() << debugname << ": Function unreachable from main: "
<< F.getName() << "\n");
calculateGraphs(&F, Stack, NextID, ValMap); // Calculate all graphs.
CloneAuxIntoGlobal(getDSGraph(F));
// Mark this graph as processed. Do this by finding all functions
// in the graph that map to it, and mark them visited.
// Note that this really should be handled neatly by calculateGraphs
// itself, not here. However this catches the worst offenders.
DSGraph *G = getDSGraph(F);
for(DSGraph::retnodes_iterator RI = G->retnodes_begin(),
RE = G->retnodes_end(); RI != RE; ++RI) {
if (getDSGraph(*RI->first) == G) {
if (!ValMap.count(RI->first))
ValMap[RI->first] = ~0U;
else
assert(ValMap[RI->first] == ~0U);
}
}
}
return;
}
void ClassHierarchyUtils::processTypeInfo(GlobalVariable* TI, Module& M) {
if (find(classes.begin(), classes.end(), TI) == classes.end()) {
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "Adding class " << TI->getName() << "\n");
classes.push_back(TI);
// First process the correspoding virtual table. We store the indexes of the primary
// and secondary vtables, indexed by the corresponding subobject offset. This will allow
// us to quickly jump to a particular sub-vtable.
if (typeInfoToVTable.find(TI) != typeInfoToVTable.end()) {
GlobalVariable* VT = typeInfoToVTable[TI];
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "Found vtable: " << VT->getName() << "\n");
ConstantStruct* VTinit = cast<ConstantStruct>(VT->getInitializer());
for (int i=0; i<VTinit->getNumOperands(); i++) {
ConstantArray* VTinitElem = cast<ConstantArray>(VTinit->getOperand(i));
for (int j=0; j<VTinitElem->getNumOperands(); j++) {
// Each sub-vtable is preceded by a reference to the class's type_info instance.
// (See https://mentorembedded.github.io/cxx-abi/abi.html).
if (TI == VTinitElem->getOperand(j)->stripPointerCasts()) {
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "Found TI at index " << i << "\n");
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "Storing mapping " << VT->getName() << " <-> " << TI->getName() << "\n");
// the offset to top is the offset from the vptr pointing to this
// sub-vtable, back to the top of the object. This will be negative,
// but the absolute value gives us the offset from the start of the
// object (i.e. first vptr), to the subobject.
int offsetToTop = 0;
if (ConstantExpr* offsetValCast = dyn_cast<ConstantExpr>(VTinitElem->getOperand(j-1)->stripPointerCasts())) {
ConstantInt* offsetVal = cast<ConstantInt>(offsetValCast->getOperand(0));
offsetToTop = offsetVal->getSExtValue(); // will be 0 for the primary
}
if (offsetToTop > 0) {
report_fatal_error("ERROR: offsetToTop is positive!");
}
else {
offsetToTop *= -1;
}
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "offsetToTop: " << offsetToTop << "\n")
vTableToSecondaryVTableMaps[VT][offsetToTop] = pair<int, int>(i, j+1);
}
}
}
}
else {
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "No vtable found for " << TI->getName() << "\n");
}
// Now process the type_info struct, extract direct base class info (what
// their subobject offsets are, or if they are virtual then their
// virtual-base-offset-offset)
if (TI->hasInitializer()) {
ConstantStruct* TIinit = cast<ConstantStruct>(TI->getInitializer());
int TInumOperands = TIinit->getNumOperands();
if (TInumOperands > 2) { // first two operands are vptr and type name
// we have >= 1 base class(es).
if (TInumOperands == 3) {
// abi::__si_class_type_info: single, public, non-virtual base at
// offset 0
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "abi::__si_class_type_info\n");
GlobalVariable* baseTI = cast<GlobalVariable>(TIinit->getOperand(2)->stripPointerCasts());
classToSubclasses[baseTI].push_back(TI);
//dbgs() << " " << *baseTI << "\n";
classToBaseOffset[TI][baseTI] = 0;
processTypeInfo(baseTI, M);
}
else {
// abi::__vmi_class_type_info: all other cases
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "abi::__vmi_class_type_info\n");
// (skip over first two additional fields, which are "flags" and "base_count")
for (int i=4; i<TInumOperands; i+=2) {
GlobalVariable* baseTI = cast<GlobalVariable>(TIinit->getOperand(i)->stripPointerCasts());
classToSubclasses[baseTI].push_back(TI);
long offset_flags = cast<ConstantInt>(TIinit->getOperand(i+1))->getSExtValue();
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << TI->getName() << " -> " << baseTI->getName() << "\n");
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << " offset_flags = " << offset_flags << "\n");
ptrdiff_t offset = offset_flags >> offset_shift;
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << " offset = " << offset << "\n");
// If this a virtual base class, then we obtain the
// vbase-offset-offset. This is the offset from the start of the
// derived class's (primary) vtable to the location containing the
// vbase-offset, which is the offset from the start of the object
// to the virtual base's subobject. Note that virtual base
// subobjects only exist once and are laid out after all other
// non-virtual objects. We keep track of the vbase-offset-offset,
// so that we can find the vbase offset when going down the class
// hierarchy. (The vbase offset may differ every time but the
// vbase-offset-offset will remain the same relative to the current
// class's vtable in subclasses).
if (offset_flags & virtual_mask) { // is this a virtual base class?
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "virtual base class: " << baseTI->getName() << "\n");
int vbaseOffsetOffset = offset/sizeof(long); // this should be negative
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "vbase-offset-offset: " << vbaseOffsetOffset << "\n");
classToVBaseOffsetOffset[TI][baseTI] = vbaseOffsetOffset;
if (typeInfoToVTable.find(TI) != typeInfoToVTable.end()) {
GlobalVariable* VT = typeInfoToVTable[TI];
int vbaseOffsetIdx = vTableToSecondaryVTableMaps[VT][0].second+vbaseOffsetOffset;
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "vbase-offset-idx: " << vbaseOffsetIdx << "\n");
}
else {
SDEBUG("soaap.util.classhierarchy", 3, dbgs() << "No VTable for " << TI->getName() << "\n");
}
}
else {
// In the non-virtual base class case, we just record the subobj
// offset. This is the offset from the start of the derived
// object to the base class's subobject. We use this information
// together with the offset-to-top info we obtained from the
// vtable to find the base class's subvtable. Note that the
// relative position of the base class subobj within the current
// derived object will always remain the same, even in
// subclasses.
classToBaseOffset[TI][baseTI] = offset;
}
//dbgs() << " " << *baseTI << "\n";
processTypeInfo(baseTI, M);
}
}
}
}
