/// CreateGlobalString - Make a new global variable with an initializer that
/// has array of i8 type filled in with the nul terminated string value
/// specified. If Name is specified, it is the name of the global variable
/// created.
Value *IRBuilderBase::CreateGlobalString(const char *Str, const Twine &Name) {
Constant *StrConstant = ConstantArray::get(Context, Str, true);
Module &M = *BB->getParent()->getParent();
GlobalVariable *GV = new GlobalVariable(M, StrConstant->getType(),
true, GlobalValue::InternalLinkage,
StrConstant, "", 0, false);
GV->setName(Name);
return GV;
}
/// CreateGlobalString - Make a new global variable with an initializer that
/// has array of i8 type filled in with the nul terminated string value
/// specified. If Name is specified, it is the name of the global variable
/// created.
Value *IRBuilderBase::CreateGlobalString(StringRef Str, const Twine &Name) {
Constant *StrConstant = ConstantDataArray::getString(Context, Str);
Module &M = *BB->getParent()->getParent();
GlobalVariable *GV = new GlobalVariable(M, StrConstant->getType(),
true, GlobalValue::PrivateLinkage,
StrConstant);
GV->setName(Name);
GV->setUnnamedAddr(true);
return GV;
}
static void defineFuncArray(Module &M, const char *LlvmArrayName,
const char *StartSymbol,
const char *EndSymbol) {
std::vector<Constant*> Funcs;
GlobalVariable *Array = M.getNamedGlobal(LlvmArrayName);
if (Array) {
readFuncList(Array, &Funcs);
// No code should be referencing global_ctors/global_dtors,
// because this symbol is internal to LLVM.
Array->eraseFromParent();
}
Type *FuncTy = FunctionType::get(Type::getVoidTy(M.getContext()), false);
Type *FuncPtrTy = FuncTy->getPointerTo();
ArrayType *ArrayTy = ArrayType::get(FuncPtrTy, Funcs.size());
GlobalVariable *NewArray =
new GlobalVariable(M, ArrayTy, /* isConstant= */ true,
GlobalValue::InternalLinkage,
ConstantArray::get(ArrayTy, Funcs));
setGlobalVariableValue(M, StartSymbol, NewArray);
// We do this last so that LLVM gives NewArray the name
// "__{init,fini}_array_start" without adding any suffixes to
// disambiguate from the original GlobalVariable's name. This is
// not essential -- it just makes the output easier to understand
// when looking at symbols for debugging.
NewArray->setName(StartSymbol);
// We replace "__{init,fini}_array_end" with the address of the end
// of NewArray. This removes the name "__{init,fini}_array_end"
// from the output, which is not ideal for debugging. Ideally we
// would convert "__{init,fini}_array_end" to being a GlobalAlias
// that points to the end of the array. However, unfortunately LLVM
// does not generate correct code when a GlobalAlias contains a
// GetElementPtr ConstantExpr.
Constant *NewArrayEnd =
ConstantExpr::getGetElementPtr(ArrayTy, NewArray,
ConstantInt::get(M.getContext(),
APInt(32, 1)));
setGlobalVariableValue(M, EndSymbol, NewArrayEnd);
}
bool GenericToNVVM::runOnModule(Module &M) {
// Create a clone of each global variable that has the default address space.
// The clone is created with the global address space specifier, and the pair
// of original global variable and its clone is placed in the GVMap for later
// use.
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E;) {
GlobalVariable *GV = &*I++;
if (GV->getType()->getAddressSpace() == llvm::ADDRESS_SPACE_GENERIC &&
!llvm::isTexture(*GV) && !llvm::isSurface(*GV) &&
!llvm::isSampler(*GV) && !GV->getName().startswith("llvm.")) {
GlobalVariable *NewGV = new GlobalVariable(
M, GV->getValueType(), GV->isConstant(),
GV->getLinkage(),
GV->hasInitializer() ? GV->getInitializer() : nullptr,
"", GV, GV->getThreadLocalMode(), llvm::ADDRESS_SPACE_GLOBAL);
NewGV->copyAttributesFrom(GV);
GVMap[GV] = NewGV;
}
}
// Return immediately, if every global variable has a specific address space
// specifier.
if (GVMap.empty()) {
return false;
}
// Walk through the instructions in function defitinions, and replace any use
// of original global variables in GVMap with a use of the corresponding
// copies in GVMap. If necessary, promote constants to instructions.
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
if (I->isDeclaration()) {
continue;
}
IRBuilder<> Builder(I->getEntryBlock().getFirstNonPHIOrDbg());
for (Function::iterator BBI = I->begin(), BBE = I->end(); BBI != BBE;
++BBI) {
for (BasicBlock::iterator II = BBI->begin(), IE = BBI->end(); II != IE;
++II) {
for (unsigned i = 0, e = II->getNumOperands(); i < e; ++i) {
Value *Operand = II->getOperand(i);
if (isa<Constant>(Operand)) {
II->setOperand(
i, remapConstant(&M, &*I, cast<Constant>(Operand), Builder));
}
}
}
}
ConstantToValueMap.clear();
}
// Copy GVMap over to a standard value map.
ValueToValueMapTy VM;
for (auto I = GVMap.begin(), E = GVMap.end(); I != E; ++I)
VM[I->first] = I->second;
// Walk through the metadata section and update the debug information
// associated with the global variables in the default address space.
for (NamedMDNode &I : M.named_metadata()) {
remapNamedMDNode(VM, &I);
}
// Walk through the global variable initializers, and replace any use of
// original global variables in GVMap with a use of the corresponding copies
// in GVMap. The copies need to be bitcast to the original global variable
// types, as we cannot use cvta in global variable initializers.
for (GVMapTy::iterator I = GVMap.begin(), E = GVMap.end(); I != E;) {
GlobalVariable *GV = I->first;
GlobalVariable *NewGV = I->second;
// Remove GV from the map so that it can be RAUWed. Note that
// DenseMap::erase() won't invalidate any iterators but this one.
auto Next = std::next(I);
GVMap.erase(I);
I = Next;
Constant *BitCastNewGV = ConstantExpr::getPointerCast(NewGV, GV->getType());
// At this point, the remaining uses of GV should be found only in global
// variable initializers, as other uses have been already been removed
// while walking through the instructions in function definitions.
GV->replaceAllUsesWith(BitCastNewGV);
std::string Name = GV->getName();
GV->eraseFromParent();
NewGV->setName(Name);
}
assert(GVMap.empty() && "Expected it to be empty by now");
return true;
}
void MetadataTransform(CallSite &CS, const TargetData *TD)
{
Instruction *I = CS.getInstruction();
Module *M = I->getParent()->getParent()->getParent();
LLVMContext &Ctx = I->getContext();
unsigned argIdx = 0;
if (CS.arg_size() < 2)
report_fatal_error(I, "_SYS_lti_metadata requires at least two args");
// Parse the 'key' parameter
ConstantInt *CI = dyn_cast<ConstantInt>(CS.getArgument(argIdx++));
if (!CI)
report_fatal_error(I, "Metadata key must be a constant integer.");
uint16_t key = CI->getZExtValue();
if (key != CI->getZExtValue())
report_fatal_error(I, "Metadata key argument is too large.");
// Parse the 'fmt' parameter
std::string fmt;
if (!GetConstantStringInfo(CS.getArgument(argIdx++), fmt))
report_fatal_error(I, "Metadata format must be a constant string.");
if (fmt.size() != CS.arg_size() - 2)
report_fatal_error(I, "Length of metadata format must match number of parameters");
if (fmt.size() == 0)
report_fatal_error(I, "Empty metadata values are not supported");
/*
* Parse every other parameter according to the format string
*/
SmallVector<Constant*, 8> Members;
unsigned align = 1;
for (std::string::iterator FI = fmt.begin(), FE = fmt.end();
FI != FE; ++FI, argIdx++) {
Constant *Arg = dyn_cast<Constant>(CS.getArgument(argIdx));
Constant *C;
if (!Arg)
report_fatal_error(I, "Metadata argument " + Twine(argIdx+1) + " is not constant");
/*
* First, non-integer types
*/
switch (*FI) {
case 's': {
std::string str;
if (!GetConstantStringInfo(Arg, str))
report_fatal_error(I, "Metadata formatter 's' requires a constant string");
Members.push_back(ConstantArray::get(Ctx, str, false));
continue;
}
}
/*
* Integer types
*/
if (Arg->getType()->isPointerTy())
Arg = ConstantExpr::getPointerCast(Arg, Type::getInt32Ty(Ctx));
if (!Arg->getType()->isIntegerTy())
report_fatal_error(I, "Metadata argument " + Twine(argIdx+1) +
" can't be converted to an integer type.");
switch (*FI) {
case 'b':
C = ConstantExpr::getIntegerCast(Arg, Type::getInt8Ty(Ctx), true);
break;
case 'B':
C = ConstantExpr::getIntegerCast(Arg, Type::getInt8Ty(Ctx), false);
break;
case 'h':
C = ConstantExpr::getIntegerCast(Arg, Type::getInt16Ty(Ctx), true);
break;
case 'H':
C = ConstantExpr::getIntegerCast(Arg, Type::getInt16Ty(Ctx), false);
break;
case 'i':
C = ConstantExpr::getIntegerCast(Arg, Type::getInt32Ty(Ctx), true);
break;
case 'I':
C = ConstantExpr::getIntegerCast(Arg, Type::getInt32Ty(Ctx), false);
break;
default:
report_fatal_error(I, "Unsupported format character '" + Twine(*FI) + "' in metadata");
}
align = std::max(align, TD->getABITypeAlignment(C->getType()));
Members.push_back(C);
}
Constant *Struct = ConstantStruct::getAnon(Members);
/*
* Install this metadata item as a global variable in a special section
*/
GlobalVariable *GV = new GlobalVariable(*M, Struct->getType(),
true, GlobalValue::ExternalLinkage, Struct, "", 0, false);
GV->setAlignment(align);
GV->setName(SVMDecorations::META + Twine(key) + SVMDecorations::SEPARATOR);
GV->setSection(".metadata");
// Remove the original _SYS_lti_metadata() call
I->eraseFromParent();
}
static PointerType *buildTlsTemplate(Module &M, std::vector<VarInfo> *TlsVars) {
std::vector<Type*> FieldBssTypes;
std::vector<Type*> FieldInitTypes;
std::vector<Constant*> FieldInitValues;
PassState State(&M);
for (Module::global_iterator GV = M.global_begin();
GV != M.global_end();
++GV) {
if (GV->isThreadLocal()) {
if (!GV->hasInitializer()) {
// Since this is a whole-program transformation, "extern" TLS
// variables are not allowed at this point.
report_fatal_error(std::string("TLS variable without an initializer: ")
+ GV->getName());
}
if (!GV->getInitializer()->isNullValue()) {
addVarToTlsTemplate(&State, &FieldInitTypes,
&FieldInitValues, GV);
VarInfo Info;
Info.TlsVar = GV;
Info.IsBss = false;
Info.TemplateIndex = FieldInitTypes.size() - 1;
TlsVars->push_back(Info);
}
}
}
// Handle zero-initialized TLS variables in a second pass, because
// these should follow non-zero-initialized TLS variables.
for (Module::global_iterator GV = M.global_begin();
GV != M.global_end();
++GV) {
if (GV->isThreadLocal() && GV->getInitializer()->isNullValue()) {
addVarToTlsTemplate(&State, &FieldBssTypes, NULL, GV);
VarInfo Info;
Info.TlsVar = GV;
Info.IsBss = true;
Info.TemplateIndex = FieldBssTypes.size() - 1;
TlsVars->push_back(Info);
}
}
// Add final alignment padding so that
// (struct tls_struct *) __nacl_read_tp() - 1
// gives the correct, aligned start of the TLS variables given the
// x86-style layout we are using. This requires some more bytes to
// be memset() to zero at runtime. This wastage doesn't seem
// important gives that we're not trying to optimize packing by
// reordering to put similarly-aligned variables together.
padToAlignment(&State, &FieldBssTypes, NULL, State.Alignment);
// We create the TLS template structs as "packed" because we insert
// alignment padding ourselves, and LLVM's implicit insertion of
// padding would interfere with ours. tls_bss_template can start at
// a non-aligned address immediately following the last field in
// tls_init_template.
StructType *InitTemplateType =
StructType::create(M.getContext(), "tls_init_template");
InitTemplateType->setBody(FieldInitTypes, /*isPacked=*/true);
StructType *BssTemplateType =
StructType::create(M.getContext(), "tls_bss_template");
BssTemplateType->setBody(FieldBssTypes, /*isPacked=*/true);
StructType *TemplateType = StructType::create(M.getContext(), "tls_struct");
SmallVector<Type*, 2> TemplateTopFields;
TemplateTopFields.push_back(InitTemplateType);
TemplateTopFields.push_back(BssTemplateType);
TemplateType->setBody(TemplateTopFields, /*isPacked=*/true);
PointerType *TemplatePtrType = PointerType::get(TemplateType, 0);
// We define the following symbols, which are the same as those
// defined by NaCl's original customized binutils linker scripts:
// __tls_template_start
// __tls_template_tdata_end
// __tls_template_end
// We also define __tls_template_alignment, which was not defined by
// the original linker scripts.
const char *StartSymbol = "__tls_template_start";
Constant *TemplateData = ConstantStruct::get(InitTemplateType,
FieldInitValues);
GlobalVariable *TemplateDataVar =
new GlobalVariable(M, InitTemplateType, /*isConstant=*/true,
GlobalValue::InternalLinkage, TemplateData);
setGlobalVariableValue(M, StartSymbol, TemplateDataVar);
TemplateDataVar->setName(StartSymbol);
Constant *TdataEnd = ConstantExpr::getGetElementPtr(
TemplateDataVar,
ConstantInt::get(M.getContext(), APInt(32, 1)));
setGlobalVariableValue(M, "__tls_template_tdata_end", TdataEnd);
Constant *TotalEnd = ConstantExpr::getGetElementPtr(
ConstantExpr::getBitCast(TemplateDataVar, TemplatePtrType),
ConstantInt::get(M.getContext(), APInt(32, 1)));
setGlobalVariableValue(M, "__tls_template_end", TotalEnd);
const char *AlignmentSymbol = "__tls_template_alignment";
Type *i32 = Type::getInt32Ty(M.getContext());
GlobalVariable *AlignmentVar = new GlobalVariable(
M, i32, /*isConstant=*/true,
GlobalValue::InternalLinkage,
ConstantInt::get(M.getContext(), APInt(32, State.Alignment)));
setGlobalVariableValue(M, AlignmentSymbol, AlignmentVar);
AlignmentVar->setName(AlignmentSymbol);
return TemplatePtrType;
}
