freebsd-dev/lib/IR/Function.cpp

1321 lines
45 KiB
C++

//===- Function.cpp - Implement the Global object classes -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Function class for the IR library.
//
//===----------------------------------------------------------------------===//
#include "LLVMContextImpl.h"
#include "SymbolTableListTraitsImpl.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/SymbolTableListTraits.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueSymbolTable.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <string>
using namespace llvm;
// Explicit instantiations of SymbolTableListTraits since some of the methods
// are not in the public header file...
template class llvm::SymbolTableListTraits<BasicBlock>;
//===----------------------------------------------------------------------===//
// Argument Implementation
//===----------------------------------------------------------------------===//
Argument::Argument(Type *Ty, const Twine &Name, Function *Par, unsigned ArgNo)
: Value(Ty, Value::ArgumentVal), Parent(Par), ArgNo(ArgNo) {
setName(Name);
}
void Argument::setParent(Function *parent) {
Parent = parent;
}
bool Argument::hasNonNullAttr() const {
if (!getType()->isPointerTy()) return false;
if (getParent()->hasParamAttribute(getArgNo(), Attribute::NonNull))
return true;
else if (getDereferenceableBytes() > 0 &&
getType()->getPointerAddressSpace() == 0)
return true;
return false;
}
bool Argument::hasByValAttr() const {
if (!getType()->isPointerTy()) return false;
return hasAttribute(Attribute::ByVal);
}
bool Argument::hasSwiftSelfAttr() const {
return getParent()->hasParamAttribute(getArgNo(), Attribute::SwiftSelf);
}
bool Argument::hasSwiftErrorAttr() const {
return getParent()->hasParamAttribute(getArgNo(), Attribute::SwiftError);
}
bool Argument::hasInAllocaAttr() const {
if (!getType()->isPointerTy()) return false;
return hasAttribute(Attribute::InAlloca);
}
bool Argument::hasByValOrInAllocaAttr() const {
if (!getType()->isPointerTy()) return false;
AttributeList Attrs = getParent()->getAttributes();
return Attrs.hasParamAttribute(getArgNo(), Attribute::ByVal) ||
Attrs.hasParamAttribute(getArgNo(), Attribute::InAlloca);
}
unsigned Argument::getParamAlignment() const {
assert(getType()->isPointerTy() && "Only pointers have alignments");
return getParent()->getParamAlignment(getArgNo());
}
uint64_t Argument::getDereferenceableBytes() const {
assert(getType()->isPointerTy() &&
"Only pointers have dereferenceable bytes");
return getParent()->getDereferenceableBytes(getArgNo() +
AttributeList::FirstArgIndex);
}
uint64_t Argument::getDereferenceableOrNullBytes() const {
assert(getType()->isPointerTy() &&
"Only pointers have dereferenceable bytes");
return getParent()->getDereferenceableOrNullBytes(
getArgNo() + AttributeList::FirstArgIndex);
}
bool Argument::hasNestAttr() const {
if (!getType()->isPointerTy()) return false;
return hasAttribute(Attribute::Nest);
}
bool Argument::hasNoAliasAttr() const {
if (!getType()->isPointerTy()) return false;
return hasAttribute(Attribute::NoAlias);
}
bool Argument::hasNoCaptureAttr() const {
if (!getType()->isPointerTy()) return false;
return hasAttribute(Attribute::NoCapture);
}
bool Argument::hasStructRetAttr() const {
if (!getType()->isPointerTy()) return false;
return hasAttribute(Attribute::StructRet);
}
bool Argument::hasReturnedAttr() const {
return hasAttribute(Attribute::Returned);
}
bool Argument::hasZExtAttr() const {
return hasAttribute(Attribute::ZExt);
}
bool Argument::hasSExtAttr() const {
return hasAttribute(Attribute::SExt);
}
bool Argument::onlyReadsMemory() const {
AttributeList Attrs = getParent()->getAttributes();
return Attrs.hasParamAttribute(getArgNo(), Attribute::ReadOnly) ||
Attrs.hasParamAttribute(getArgNo(), Attribute::ReadNone);
}
void Argument::addAttrs(AttrBuilder &B) {
AttributeList AL = getParent()->getAttributes();
AL = AL.addAttributes(Parent->getContext(),
getArgNo() + AttributeList::FirstArgIndex, B);
getParent()->setAttributes(AL);
}
void Argument::addAttr(Attribute::AttrKind Kind) {
getParent()->addAttribute(getArgNo() + AttributeList::FirstArgIndex, Kind);
}
void Argument::addAttr(Attribute Attr) {
getParent()->addAttribute(getArgNo() + AttributeList::FirstArgIndex, Attr);
}
void Argument::removeAttr(Attribute::AttrKind Kind) {
getParent()->removeAttribute(getArgNo() + AttributeList::FirstArgIndex, Kind);
}
bool Argument::hasAttribute(Attribute::AttrKind Kind) const {
return getParent()->hasParamAttribute(getArgNo(), Kind);
}
//===----------------------------------------------------------------------===//
// Helper Methods in Function
//===----------------------------------------------------------------------===//
LLVMContext &Function::getContext() const {
return getType()->getContext();
}
void Function::removeFromParent() {
getParent()->getFunctionList().remove(getIterator());
}
void Function::eraseFromParent() {
getParent()->getFunctionList().erase(getIterator());
}
//===----------------------------------------------------------------------===//
// Function Implementation
//===----------------------------------------------------------------------===//
Function::Function(FunctionType *Ty, LinkageTypes Linkage, const Twine &name,
Module *ParentModule)
: GlobalObject(Ty, Value::FunctionVal,
OperandTraits<Function>::op_begin(this), 0, Linkage, name),
NumArgs(Ty->getNumParams()) {
assert(FunctionType::isValidReturnType(getReturnType()) &&
"invalid return type");
setGlobalObjectSubClassData(0);
// We only need a symbol table for a function if the context keeps value names
if (!getContext().shouldDiscardValueNames())
SymTab = make_unique<ValueSymbolTable>();
// If the function has arguments, mark them as lazily built.
if (Ty->getNumParams())
setValueSubclassData(1); // Set the "has lazy arguments" bit.
if (ParentModule)
ParentModule->getFunctionList().push_back(this);
HasLLVMReservedName = getName().startswith("llvm.");
// Ensure intrinsics have the right parameter attributes.
// Note, the IntID field will have been set in Value::setName if this function
// name is a valid intrinsic ID.
if (IntID)
setAttributes(Intrinsic::getAttributes(getContext(), IntID));
}
Function::~Function() {
dropAllReferences(); // After this it is safe to delete instructions.
// Delete all of the method arguments and unlink from symbol table...
if (Arguments)
clearArguments();
// Remove the function from the on-the-side GC table.
clearGC();
}
void Function::BuildLazyArguments() const {
// Create the arguments vector, all arguments start out unnamed.
auto *FT = getFunctionType();
if (NumArgs > 0) {
Arguments = std::allocator<Argument>().allocate(NumArgs);
for (unsigned i = 0, e = NumArgs; i != e; ++i) {
Type *ArgTy = FT->getParamType(i);
assert(!ArgTy->isVoidTy() && "Cannot have void typed arguments!");
new (Arguments + i) Argument(ArgTy, "", const_cast<Function *>(this), i);
}
}
// Clear the lazy arguments bit.
unsigned SDC = getSubclassDataFromValue();
const_cast<Function*>(this)->setValueSubclassData(SDC &= ~(1<<0));
assert(!hasLazyArguments());
}
static MutableArrayRef<Argument> makeArgArray(Argument *Args, size_t Count) {
return MutableArrayRef<Argument>(Args, Count);
}
void Function::clearArguments() {
for (Argument &A : makeArgArray(Arguments, NumArgs)) {
A.setName("");
A.~Argument();
}
std::allocator<Argument>().deallocate(Arguments, NumArgs);
Arguments = nullptr;
}
void Function::stealArgumentListFrom(Function &Src) {
assert(isDeclaration() && "Expected no references to current arguments");
// Drop the current arguments, if any, and set the lazy argument bit.
if (!hasLazyArguments()) {
assert(llvm::all_of(makeArgArray(Arguments, NumArgs),
[](const Argument &A) { return A.use_empty(); }) &&
"Expected arguments to be unused in declaration");
clearArguments();
setValueSubclassData(getSubclassDataFromValue() | (1 << 0));
}
// Nothing to steal if Src has lazy arguments.
if (Src.hasLazyArguments())
return;
// Steal arguments from Src, and fix the lazy argument bits.
assert(arg_size() == Src.arg_size());
Arguments = Src.Arguments;
Src.Arguments = nullptr;
for (Argument &A : makeArgArray(Arguments, NumArgs)) {
// FIXME: This does the work of transferNodesFromList inefficiently.
SmallString<128> Name;
if (A.hasName())
Name = A.getName();
if (!Name.empty())
A.setName("");
A.setParent(this);
if (!Name.empty())
A.setName(Name);
}
setValueSubclassData(getSubclassDataFromValue() & ~(1 << 0));
assert(!hasLazyArguments());
Src.setValueSubclassData(Src.getSubclassDataFromValue() | (1 << 0));
}
// dropAllReferences() - This function causes all the subinstructions to "let
// go" of all references that they are maintaining. This allows one to
// 'delete' a whole class at a time, even though there may be circular
// references... first all references are dropped, and all use counts go to
// zero. Then everything is deleted for real. Note that no operations are
// valid on an object that has "dropped all references", except operator
// delete.
//
void Function::dropAllReferences() {
setIsMaterializable(false);
for (BasicBlock &BB : *this)
BB.dropAllReferences();
// Delete all basic blocks. They are now unused, except possibly by
// blockaddresses, but BasicBlock's destructor takes care of those.
while (!BasicBlocks.empty())
BasicBlocks.begin()->eraseFromParent();
// Drop uses of any optional data (real or placeholder).
if (getNumOperands()) {
User::dropAllReferences();
setNumHungOffUseOperands(0);
setValueSubclassData(getSubclassDataFromValue() & ~0xe);
}
// Metadata is stored in a side-table.
clearMetadata();
}
void Function::addAttribute(unsigned i, Attribute::AttrKind Kind) {
AttributeList PAL = getAttributes();
PAL = PAL.addAttribute(getContext(), i, Kind);
setAttributes(PAL);
}
void Function::addAttribute(unsigned i, Attribute Attr) {
AttributeList PAL = getAttributes();
PAL = PAL.addAttribute(getContext(), i, Attr);
setAttributes(PAL);
}
void Function::addAttributes(unsigned i, const AttrBuilder &Attrs) {
AttributeList PAL = getAttributes();
PAL = PAL.addAttributes(getContext(), i, Attrs);
setAttributes(PAL);
}
void Function::removeAttribute(unsigned i, Attribute::AttrKind Kind) {
AttributeList PAL = getAttributes();
PAL = PAL.removeAttribute(getContext(), i, Kind);
setAttributes(PAL);
}
void Function::removeAttribute(unsigned i, StringRef Kind) {
AttributeList PAL = getAttributes();
PAL = PAL.removeAttribute(getContext(), i, Kind);
setAttributes(PAL);
}
void Function::removeAttributes(unsigned i, const AttrBuilder &Attrs) {
AttributeList PAL = getAttributes();
PAL = PAL.removeAttributes(getContext(), i, Attrs);
setAttributes(PAL);
}
void Function::addDereferenceableAttr(unsigned i, uint64_t Bytes) {
AttributeList PAL = getAttributes();
PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
setAttributes(PAL);
}
void Function::addDereferenceableOrNullAttr(unsigned i, uint64_t Bytes) {
AttributeList PAL = getAttributes();
PAL = PAL.addDereferenceableOrNullAttr(getContext(), i, Bytes);
setAttributes(PAL);
}
const std::string &Function::getGC() const {
assert(hasGC() && "Function has no collector");
return getContext().getGC(*this);
}
void Function::setGC(std::string Str) {
setValueSubclassDataBit(14, !Str.empty());
getContext().setGC(*this, std::move(Str));
}
void Function::clearGC() {
if (!hasGC())
return;
getContext().deleteGC(*this);
setValueSubclassDataBit(14, false);
}
/// Copy all additional attributes (those not needed to create a Function) from
/// the Function Src to this one.
void Function::copyAttributesFrom(const Function *Src) {
GlobalObject::copyAttributesFrom(Src);
setCallingConv(Src->getCallingConv());
setAttributes(Src->getAttributes());
if (Src->hasGC())
setGC(Src->getGC());
else
clearGC();
if (Src->hasPersonalityFn())
setPersonalityFn(Src->getPersonalityFn());
if (Src->hasPrefixData())
setPrefixData(Src->getPrefixData());
if (Src->hasPrologueData())
setPrologueData(Src->getPrologueData());
}
/// Table of string intrinsic names indexed by enum value.
static const char * const IntrinsicNameTable[] = {
"not_intrinsic",
#define GET_INTRINSIC_NAME_TABLE
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_NAME_TABLE
};
/// Table of per-target intrinsic name tables.
#define GET_INTRINSIC_TARGET_DATA
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_TARGET_DATA
/// Find the segment of \c IntrinsicNameTable for intrinsics with the same
/// target as \c Name, or the generic table if \c Name is not target specific.
///
/// Returns the relevant slice of \c IntrinsicNameTable
static ArrayRef<const char *> findTargetSubtable(StringRef Name) {
assert(Name.startswith("llvm."));
ArrayRef<IntrinsicTargetInfo> Targets(TargetInfos);
// Drop "llvm." and take the first dotted component. That will be the target
// if this is target specific.
StringRef Target = Name.drop_front(5).split('.').first;
auto It = std::lower_bound(Targets.begin(), Targets.end(), Target,
[](const IntrinsicTargetInfo &TI,
StringRef Target) { return TI.Name < Target; });
// We've either found the target or just fall back to the generic set, which
// is always first.
const auto &TI = It != Targets.end() && It->Name == Target ? *It : Targets[0];
return makeArrayRef(&IntrinsicNameTable[1] + TI.Offset, TI.Count);
}
/// \brief This does the actual lookup of an intrinsic ID which
/// matches the given function name.
Intrinsic::ID Function::lookupIntrinsicID(StringRef Name) {
ArrayRef<const char *> NameTable = findTargetSubtable(Name);
int Idx = Intrinsic::lookupLLVMIntrinsicByName(NameTable, Name);
if (Idx == -1)
return Intrinsic::not_intrinsic;
// Intrinsic IDs correspond to the location in IntrinsicNameTable, but we have
// an index into a sub-table.
int Adjust = NameTable.data() - IntrinsicNameTable;
Intrinsic::ID ID = static_cast<Intrinsic::ID>(Idx + Adjust);
// If the intrinsic is not overloaded, require an exact match. If it is
// overloaded, require a prefix match.
bool IsPrefixMatch = Name.size() > strlen(NameTable[Idx]);
return IsPrefixMatch == isOverloaded(ID) ? ID : Intrinsic::not_intrinsic;
}
void Function::recalculateIntrinsicID() {
StringRef Name = getName();
if (!Name.startswith("llvm.")) {
HasLLVMReservedName = false;
IntID = Intrinsic::not_intrinsic;
return;
}
HasLLVMReservedName = true;
IntID = lookupIntrinsicID(Name);
}
/// Returns a stable mangling for the type specified for use in the name
/// mangling scheme used by 'any' types in intrinsic signatures. The mangling
/// of named types is simply their name. Manglings for unnamed types consist
/// of a prefix ('p' for pointers, 'a' for arrays, 'f_' for functions)
/// combined with the mangling of their component types. A vararg function
/// type will have a suffix of 'vararg'. Since function types can contain
/// other function types, we close a function type mangling with suffix 'f'
/// which can't be confused with it's prefix. This ensures we don't have
/// collisions between two unrelated function types. Otherwise, you might
/// parse ffXX as f(fXX) or f(fX)X. (X is a placeholder for any other type.)
/// Manglings of integers, floats, and vectors ('i', 'f', and 'v' prefix in most
/// cases) fall back to the MVT codepath, where they could be mangled to
/// 'x86mmx', for example; matching on derived types is not sufficient to mangle
/// everything.
static std::string getMangledTypeStr(Type* Ty) {
std::string Result;
if (PointerType* PTyp = dyn_cast<PointerType>(Ty)) {
Result += "p" + utostr(PTyp->getAddressSpace()) +
getMangledTypeStr(PTyp->getElementType());
} else if (ArrayType* ATyp = dyn_cast<ArrayType>(Ty)) {
Result += "a" + utostr(ATyp->getNumElements()) +
getMangledTypeStr(ATyp->getElementType());
} else if (StructType *STyp = dyn_cast<StructType>(Ty)) {
if (!STyp->isLiteral()) {
Result += "s_";
Result += STyp->getName();
} else {
Result += "sl_";
for (auto Elem : STyp->elements())
Result += getMangledTypeStr(Elem);
}
// Ensure nested structs are distinguishable.
Result += "s";
} else if (FunctionType *FT = dyn_cast<FunctionType>(Ty)) {
Result += "f_" + getMangledTypeStr(FT->getReturnType());
for (size_t i = 0; i < FT->getNumParams(); i++)
Result += getMangledTypeStr(FT->getParamType(i));
if (FT->isVarArg())
Result += "vararg";
// Ensure nested function types are distinguishable.
Result += "f";
} else if (isa<VectorType>(Ty))
Result += "v" + utostr(Ty->getVectorNumElements()) +
getMangledTypeStr(Ty->getVectorElementType());
else if (Ty)
Result += EVT::getEVT(Ty).getEVTString();
return Result;
}
StringRef Intrinsic::getName(ID id) {
assert(id < num_intrinsics && "Invalid intrinsic ID!");
assert(!isOverloaded(id) &&
"This version of getName does not support overloading");
return IntrinsicNameTable[id];
}
std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) {
assert(id < num_intrinsics && "Invalid intrinsic ID!");
std::string Result(IntrinsicNameTable[id]);
for (Type *Ty : Tys) {
Result += "." + getMangledTypeStr(Ty);
}
return Result;
}
/// IIT_Info - These are enumerators that describe the entries returned by the
/// getIntrinsicInfoTableEntries function.
///
/// NOTE: This must be kept in synch with the copy in TblGen/IntrinsicEmitter!
enum IIT_Info {
// Common values should be encoded with 0-15.
IIT_Done = 0,
IIT_I1 = 1,
IIT_I8 = 2,
IIT_I16 = 3,
IIT_I32 = 4,
IIT_I64 = 5,
IIT_F16 = 6,
IIT_F32 = 7,
IIT_F64 = 8,
IIT_V2 = 9,
IIT_V4 = 10,
IIT_V8 = 11,
IIT_V16 = 12,
IIT_V32 = 13,
IIT_PTR = 14,
IIT_ARG = 15,
// Values from 16+ are only encodable with the inefficient encoding.
IIT_V64 = 16,
IIT_MMX = 17,
IIT_TOKEN = 18,
IIT_METADATA = 19,
IIT_EMPTYSTRUCT = 20,
IIT_STRUCT2 = 21,
IIT_STRUCT3 = 22,
IIT_STRUCT4 = 23,
IIT_STRUCT5 = 24,
IIT_EXTEND_ARG = 25,
IIT_TRUNC_ARG = 26,
IIT_ANYPTR = 27,
IIT_V1 = 28,
IIT_VARARG = 29,
IIT_HALF_VEC_ARG = 30,
IIT_SAME_VEC_WIDTH_ARG = 31,
IIT_PTR_TO_ARG = 32,
IIT_PTR_TO_ELT = 33,
IIT_VEC_OF_ANYPTRS_TO_ELT = 34,
IIT_I128 = 35,
IIT_V512 = 36,
IIT_V1024 = 37
};
static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
using namespace Intrinsic;
IIT_Info Info = IIT_Info(Infos[NextElt++]);
unsigned StructElts = 2;
switch (Info) {
case IIT_Done:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Void, 0));
return;
case IIT_VARARG:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::VarArg, 0));
return;
case IIT_MMX:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::MMX, 0));
return;
case IIT_TOKEN:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Token, 0));
return;
case IIT_METADATA:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Metadata, 0));
return;
case IIT_F16:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Half, 0));
return;
case IIT_F32:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Float, 0));
return;
case IIT_F64:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Double, 0));
return;
case IIT_I1:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 1));
return;
case IIT_I8:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 8));
return;
case IIT_I16:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer,16));
return;
case IIT_I32:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 32));
return;
case IIT_I64:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 64));
return;
case IIT_I128:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 128));
return;
case IIT_V1:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 1));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V2:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 2));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V4:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 4));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V8:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 8));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V16:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 16));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V32:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 32));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V64:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 64));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V512:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 512));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_V1024:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 1024));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_PTR:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer, 0));
DecodeIITType(NextElt, Infos, OutputTable);
return;
case IIT_ANYPTR: { // [ANYPTR addrspace, subtype]
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer,
Infos[NextElt++]));
DecodeIITType(NextElt, Infos, OutputTable);
return;
}
case IIT_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Argument, ArgInfo));
return;
}
case IIT_EXTEND_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::ExtendArgument,
ArgInfo));
return;
}
case IIT_TRUNC_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::TruncArgument,
ArgInfo));
return;
}
case IIT_HALF_VEC_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::HalfVecArgument,
ArgInfo));
return;
}
case IIT_SAME_VEC_WIDTH_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::SameVecWidthArgument,
ArgInfo));
return;
}
case IIT_PTR_TO_ARG: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::PtrToArgument,
ArgInfo));
return;
}
case IIT_PTR_TO_ELT: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::PtrToElt, ArgInfo));
return;
}
case IIT_VEC_OF_ANYPTRS_TO_ELT: {
unsigned short ArgNo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
unsigned short RefNo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(
IITDescriptor::get(IITDescriptor::VecOfAnyPtrsToElt, ArgNo, RefNo));
return;
}
case IIT_EMPTYSTRUCT:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
return;
case IIT_STRUCT5: ++StructElts; LLVM_FALLTHROUGH;
case IIT_STRUCT4: ++StructElts; LLVM_FALLTHROUGH;
case IIT_STRUCT3: ++StructElts; LLVM_FALLTHROUGH;
case IIT_STRUCT2: {
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
for (unsigned i = 0; i != StructElts; ++i)
DecodeIITType(NextElt, Infos, OutputTable);
return;
}
}
llvm_unreachable("unhandled");
}
#define GET_INTRINSIC_GENERATOR_GLOBAL
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_GENERATOR_GLOBAL
void Intrinsic::getIntrinsicInfoTableEntries(ID id,
SmallVectorImpl<IITDescriptor> &T){
// Check to see if the intrinsic's type was expressible by the table.
unsigned TableVal = IIT_Table[id-1];
// Decode the TableVal into an array of IITValues.
SmallVector<unsigned char, 8> IITValues;
ArrayRef<unsigned char> IITEntries;
unsigned NextElt = 0;
if ((TableVal >> 31) != 0) {
// This is an offset into the IIT_LongEncodingTable.
IITEntries = IIT_LongEncodingTable;
// Strip sentinel bit.
NextElt = (TableVal << 1) >> 1;
} else {
// Decode the TableVal into an array of IITValues. If the entry was encoded
// into a single word in the table itself, decode it now.
do {
IITValues.push_back(TableVal & 0xF);
TableVal >>= 4;
} while (TableVal);
IITEntries = IITValues;
NextElt = 0;
}
// Okay, decode the table into the output vector of IITDescriptors.
DecodeIITType(NextElt, IITEntries, T);
while (NextElt != IITEntries.size() && IITEntries[NextElt] != 0)
DecodeIITType(NextElt, IITEntries, T);
}
static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,
ArrayRef<Type*> Tys, LLVMContext &Context) {
using namespace Intrinsic;
IITDescriptor D = Infos.front();
Infos = Infos.slice(1);
switch (D.Kind) {
case IITDescriptor::Void: return Type::getVoidTy(Context);
case IITDescriptor::VarArg: return Type::getVoidTy(Context);
case IITDescriptor::MMX: return Type::getX86_MMXTy(Context);
case IITDescriptor::Token: return Type::getTokenTy(Context);
case IITDescriptor::Metadata: return Type::getMetadataTy(Context);
case IITDescriptor::Half: return Type::getHalfTy(Context);
case IITDescriptor::Float: return Type::getFloatTy(Context);
case IITDescriptor::Double: return Type::getDoubleTy(Context);
case IITDescriptor::Integer:
return IntegerType::get(Context, D.Integer_Width);
case IITDescriptor::Vector:
return VectorType::get(DecodeFixedType(Infos, Tys, Context),D.Vector_Width);
case IITDescriptor::Pointer:
return PointerType::get(DecodeFixedType(Infos, Tys, Context),
D.Pointer_AddressSpace);
case IITDescriptor::Struct: {
Type *Elts[5];
assert(D.Struct_NumElements <= 5 && "Can't handle this yet");
for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
Elts[i] = DecodeFixedType(Infos, Tys, Context);
return StructType::get(Context, makeArrayRef(Elts,D.Struct_NumElements));
}
case IITDescriptor::Argument:
return Tys[D.getArgumentNumber()];
case IITDescriptor::ExtendArgument: {
Type *Ty = Tys[D.getArgumentNumber()];
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return VectorType::getExtendedElementVectorType(VTy);
return IntegerType::get(Context, 2 * cast<IntegerType>(Ty)->getBitWidth());
}
case IITDescriptor::TruncArgument: {
Type *Ty = Tys[D.getArgumentNumber()];
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return VectorType::getTruncatedElementVectorType(VTy);
IntegerType *ITy = cast<IntegerType>(Ty);
assert(ITy->getBitWidth() % 2 == 0);
return IntegerType::get(Context, ITy->getBitWidth() / 2);
}
case IITDescriptor::HalfVecArgument:
return VectorType::getHalfElementsVectorType(cast<VectorType>(
Tys[D.getArgumentNumber()]));
case IITDescriptor::SameVecWidthArgument: {
Type *EltTy = DecodeFixedType(Infos, Tys, Context);
Type *Ty = Tys[D.getArgumentNumber()];
if (VectorType *VTy = dyn_cast<VectorType>(Ty)) {
return VectorType::get(EltTy, VTy->getNumElements());
}
llvm_unreachable("unhandled");
}
case IITDescriptor::PtrToArgument: {
Type *Ty = Tys[D.getArgumentNumber()];
return PointerType::getUnqual(Ty);
}
case IITDescriptor::PtrToElt: {
Type *Ty = Tys[D.getArgumentNumber()];
VectorType *VTy = dyn_cast<VectorType>(Ty);
if (!VTy)
llvm_unreachable("Expected an argument of Vector Type");
Type *EltTy = VTy->getVectorElementType();
return PointerType::getUnqual(EltTy);
}
case IITDescriptor::VecOfAnyPtrsToElt:
// Return the overloaded type (which determines the pointers address space)
return Tys[D.getOverloadArgNumber()];
}
llvm_unreachable("unhandled");
}
FunctionType *Intrinsic::getType(LLVMContext &Context,
ID id, ArrayRef<Type*> Tys) {
SmallVector<IITDescriptor, 8> Table;
getIntrinsicInfoTableEntries(id, Table);
ArrayRef<IITDescriptor> TableRef = Table;
Type *ResultTy = DecodeFixedType(TableRef, Tys, Context);
SmallVector<Type*, 8> ArgTys;
while (!TableRef.empty())
ArgTys.push_back(DecodeFixedType(TableRef, Tys, Context));
// DecodeFixedType returns Void for IITDescriptor::Void and IITDescriptor::VarArg
// If we see void type as the type of the last argument, it is vararg intrinsic
if (!ArgTys.empty() && ArgTys.back()->isVoidTy()) {
ArgTys.pop_back();
return FunctionType::get(ResultTy, ArgTys, true);
}
return FunctionType::get(ResultTy, ArgTys, false);
}
bool Intrinsic::isOverloaded(ID id) {
#define GET_INTRINSIC_OVERLOAD_TABLE
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_OVERLOAD_TABLE
}
bool Intrinsic::isLeaf(ID id) {
switch (id) {
default:
return true;
case Intrinsic::experimental_gc_statepoint:
case Intrinsic::experimental_patchpoint_void:
case Intrinsic::experimental_patchpoint_i64:
return false;
}
}
/// This defines the "Intrinsic::getAttributes(ID id)" method.
#define GET_INTRINSIC_ATTRIBUTES
#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_ATTRIBUTES
Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
// There can never be multiple globals with the same name of different types,
// because intrinsics must be a specific type.
return
cast<Function>(M->getOrInsertFunction(getName(id, Tys),
getType(M->getContext(), id, Tys)));
}
// This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
#define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
#include "llvm/IR/Intrinsics.gen"
#undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
// This defines the "Intrinsic::getIntrinsicForMSBuiltin()" method.
#define GET_LLVM_INTRINSIC_FOR_MS_BUILTIN
#include "llvm/IR/Intrinsics.gen"
#undef GET_LLVM_INTRINSIC_FOR_MS_BUILTIN
bool Intrinsic::matchIntrinsicType(Type *Ty, ArrayRef<Intrinsic::IITDescriptor> &Infos,
SmallVectorImpl<Type*> &ArgTys) {
using namespace Intrinsic;
// If we ran out of descriptors, there are too many arguments.
if (Infos.empty()) return true;
IITDescriptor D = Infos.front();
Infos = Infos.slice(1);
switch (D.Kind) {
case IITDescriptor::Void: return !Ty->isVoidTy();
case IITDescriptor::VarArg: return true;
case IITDescriptor::MMX: return !Ty->isX86_MMXTy();
case IITDescriptor::Token: return !Ty->isTokenTy();
case IITDescriptor::Metadata: return !Ty->isMetadataTy();
case IITDescriptor::Half: return !Ty->isHalfTy();
case IITDescriptor::Float: return !Ty->isFloatTy();
case IITDescriptor::Double: return !Ty->isDoubleTy();
case IITDescriptor::Integer: return !Ty->isIntegerTy(D.Integer_Width);
case IITDescriptor::Vector: {
VectorType *VT = dyn_cast<VectorType>(Ty);
return !VT || VT->getNumElements() != D.Vector_Width ||
matchIntrinsicType(VT->getElementType(), Infos, ArgTys);
}
case IITDescriptor::Pointer: {
PointerType *PT = dyn_cast<PointerType>(Ty);
return !PT || PT->getAddressSpace() != D.Pointer_AddressSpace ||
matchIntrinsicType(PT->getElementType(), Infos, ArgTys);
}
case IITDescriptor::Struct: {
StructType *ST = dyn_cast<StructType>(Ty);
if (!ST || ST->getNumElements() != D.Struct_NumElements)
return true;
for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
if (matchIntrinsicType(ST->getElementType(i), Infos, ArgTys))
return true;
return false;
}
case IITDescriptor::Argument:
// Two cases here - If this is the second occurrence of an argument, verify
// that the later instance matches the previous instance.
if (D.getArgumentNumber() < ArgTys.size())
return Ty != ArgTys[D.getArgumentNumber()];
// Otherwise, if this is the first instance of an argument, record it and
// verify the "Any" kind.
assert(D.getArgumentNumber() == ArgTys.size() && "Table consistency error");
ArgTys.push_back(Ty);
switch (D.getArgumentKind()) {
case IITDescriptor::AK_Any: return false; // Success
case IITDescriptor::AK_AnyInteger: return !Ty->isIntOrIntVectorTy();
case IITDescriptor::AK_AnyFloat: return !Ty->isFPOrFPVectorTy();
case IITDescriptor::AK_AnyVector: return !isa<VectorType>(Ty);
case IITDescriptor::AK_AnyPointer: return !isa<PointerType>(Ty);
}
llvm_unreachable("all argument kinds not covered");
case IITDescriptor::ExtendArgument: {
// This may only be used when referring to a previous vector argument.
if (D.getArgumentNumber() >= ArgTys.size())
return true;
Type *NewTy = ArgTys[D.getArgumentNumber()];
if (VectorType *VTy = dyn_cast<VectorType>(NewTy))
NewTy = VectorType::getExtendedElementVectorType(VTy);
else if (IntegerType *ITy = dyn_cast<IntegerType>(NewTy))
NewTy = IntegerType::get(ITy->getContext(), 2 * ITy->getBitWidth());
else
return true;
return Ty != NewTy;
}
case IITDescriptor::TruncArgument: {
// This may only be used when referring to a previous vector argument.
if (D.getArgumentNumber() >= ArgTys.size())
return true;
Type *NewTy = ArgTys[D.getArgumentNumber()];
if (VectorType *VTy = dyn_cast<VectorType>(NewTy))
NewTy = VectorType::getTruncatedElementVectorType(VTy);
else if (IntegerType *ITy = dyn_cast<IntegerType>(NewTy))
NewTy = IntegerType::get(ITy->getContext(), ITy->getBitWidth() / 2);
else
return true;
return Ty != NewTy;
}
case IITDescriptor::HalfVecArgument:
// This may only be used when referring to a previous vector argument.
return D.getArgumentNumber() >= ArgTys.size() ||
!isa<VectorType>(ArgTys[D.getArgumentNumber()]) ||
VectorType::getHalfElementsVectorType(
cast<VectorType>(ArgTys[D.getArgumentNumber()])) != Ty;
case IITDescriptor::SameVecWidthArgument: {
if (D.getArgumentNumber() >= ArgTys.size())
return true;
VectorType * ReferenceType =
dyn_cast<VectorType>(ArgTys[D.getArgumentNumber()]);
VectorType *ThisArgType = dyn_cast<VectorType>(Ty);
if (!ThisArgType || !ReferenceType ||
(ReferenceType->getVectorNumElements() !=
ThisArgType->getVectorNumElements()))
return true;
return matchIntrinsicType(ThisArgType->getVectorElementType(),
Infos, ArgTys);
}
case IITDescriptor::PtrToArgument: {
if (D.getArgumentNumber() >= ArgTys.size())
return true;
Type * ReferenceType = ArgTys[D.getArgumentNumber()];
PointerType *ThisArgType = dyn_cast<PointerType>(Ty);
return (!ThisArgType || ThisArgType->getElementType() != ReferenceType);
}
case IITDescriptor::PtrToElt: {
if (D.getArgumentNumber() >= ArgTys.size())
return true;
VectorType * ReferenceType =
dyn_cast<VectorType> (ArgTys[D.getArgumentNumber()]);
PointerType *ThisArgType = dyn_cast<PointerType>(Ty);
return (!ThisArgType || !ReferenceType ||
ThisArgType->getElementType() != ReferenceType->getElementType());
}
case IITDescriptor::VecOfAnyPtrsToElt: {
unsigned RefArgNumber = D.getRefArgNumber();
// This may only be used when referring to a previous argument.
if (RefArgNumber >= ArgTys.size())
return true;
// Record the overloaded type
assert(D.getOverloadArgNumber() == ArgTys.size() &&
"Table consistency error");
ArgTys.push_back(Ty);
// Verify the overloaded type "matches" the Ref type.
// i.e. Ty is a vector with the same width as Ref.
// Composed of pointers to the same element type as Ref.
VectorType *ReferenceType = dyn_cast<VectorType>(ArgTys[RefArgNumber]);
VectorType *ThisArgVecTy = dyn_cast<VectorType>(Ty);
if (!ThisArgVecTy || !ReferenceType ||
(ReferenceType->getVectorNumElements() !=
ThisArgVecTy->getVectorNumElements()))
return true;
PointerType *ThisArgEltTy =
dyn_cast<PointerType>(ThisArgVecTy->getVectorElementType());
if (!ThisArgEltTy)
return true;
return ThisArgEltTy->getElementType() !=
ReferenceType->getVectorElementType();
}
}
llvm_unreachable("unhandled");
}
bool
Intrinsic::matchIntrinsicVarArg(bool isVarArg,
ArrayRef<Intrinsic::IITDescriptor> &Infos) {
// If there are no descriptors left, then it can't be a vararg.
if (Infos.empty())
return isVarArg;
// There should be only one descriptor remaining at this point.
if (Infos.size() != 1)
return true;
// Check and verify the descriptor.
IITDescriptor D = Infos.front();
Infos = Infos.slice(1);
if (D.Kind == IITDescriptor::VarArg)
return !isVarArg;
return true;
}
Optional<Function*> Intrinsic::remangleIntrinsicFunction(Function *F) {
Intrinsic::ID ID = F->getIntrinsicID();
if (!ID)
return None;
FunctionType *FTy = F->getFunctionType();
// Accumulate an array of overloaded types for the given intrinsic
SmallVector<Type *, 4> ArgTys;
{
SmallVector<Intrinsic::IITDescriptor, 8> Table;
getIntrinsicInfoTableEntries(ID, Table);
ArrayRef<Intrinsic::IITDescriptor> TableRef = Table;
// If we encounter any problems matching the signature with the descriptor
// just give up remangling. It's up to verifier to report the discrepancy.
if (Intrinsic::matchIntrinsicType(FTy->getReturnType(), TableRef, ArgTys))
return None;
for (auto Ty : FTy->params())
if (Intrinsic::matchIntrinsicType(Ty, TableRef, ArgTys))
return None;
if (Intrinsic::matchIntrinsicVarArg(FTy->isVarArg(), TableRef))
return None;
}
StringRef Name = F->getName();
if (Name == Intrinsic::getName(ID, ArgTys))
return None;
auto NewDecl = Intrinsic::getDeclaration(F->getParent(), ID, ArgTys);
NewDecl->setCallingConv(F->getCallingConv());
assert(NewDecl->getFunctionType() == FTy && "Shouldn't change the signature");
return NewDecl;
}
/// hasAddressTaken - returns true if there are any uses of this function
/// other than direct calls or invokes to it.
bool Function::hasAddressTaken(const User* *PutOffender) const {
for (const Use &U : uses()) {
const User *FU = U.getUser();
if (isa<BlockAddress>(FU))
continue;
if (!isa<CallInst>(FU) && !isa<InvokeInst>(FU)) {
if (PutOffender)
*PutOffender = FU;
return true;
}
ImmutableCallSite CS(cast<Instruction>(FU));
if (!CS.isCallee(&U)) {
if (PutOffender)
*PutOffender = FU;
return true;
}
}
return false;
}
bool Function::isDefTriviallyDead() const {
// Check the linkage
if (!hasLinkOnceLinkage() && !hasLocalLinkage() &&
!hasAvailableExternallyLinkage())
return false;
// Check if the function is used by anything other than a blockaddress.
for (const User *U : users())
if (!isa<BlockAddress>(U))
return false;
return true;
}
/// callsFunctionThatReturnsTwice - Return true if the function has a call to
/// setjmp or other function that gcc recognizes as "returning twice".
bool Function::callsFunctionThatReturnsTwice() const {
for (const_inst_iterator
I = inst_begin(this), E = inst_end(this); I != E; ++I) {
ImmutableCallSite CS(&*I);
if (CS && CS.hasFnAttr(Attribute::ReturnsTwice))
return true;
}
return false;
}
Constant *Function::getPersonalityFn() const {
assert(hasPersonalityFn() && getNumOperands());
return cast<Constant>(Op<0>());
}
void Function::setPersonalityFn(Constant *Fn) {
setHungoffOperand<0>(Fn);
setValueSubclassDataBit(3, Fn != nullptr);
}
Constant *Function::getPrefixData() const {
assert(hasPrefixData() && getNumOperands());
return cast<Constant>(Op<1>());
}
void Function::setPrefixData(Constant *PrefixData) {
setHungoffOperand<1>(PrefixData);
setValueSubclassDataBit(1, PrefixData != nullptr);
}
Constant *Function::getPrologueData() const {
assert(hasPrologueData() && getNumOperands());
return cast<Constant>(Op<2>());
}
void Function::setPrologueData(Constant *PrologueData) {
setHungoffOperand<2>(PrologueData);
setValueSubclassDataBit(2, PrologueData != nullptr);
}
void Function::allocHungoffUselist() {
// If we've already allocated a uselist, stop here.
if (getNumOperands())
return;
allocHungoffUses(3, /*IsPhi=*/ false);
setNumHungOffUseOperands(3);
// Initialize the uselist with placeholder operands to allow traversal.
auto *CPN = ConstantPointerNull::get(Type::getInt1PtrTy(getContext(), 0));
Op<0>().set(CPN);
Op<1>().set(CPN);
Op<2>().set(CPN);
}
template <int Idx>
void Function::setHungoffOperand(Constant *C) {
if (C) {
allocHungoffUselist();
Op<Idx>().set(C);
} else if (getNumOperands()) {
Op<Idx>().set(
ConstantPointerNull::get(Type::getInt1PtrTy(getContext(), 0)));
}
}
void Function::setValueSubclassDataBit(unsigned Bit, bool On) {
assert(Bit < 16 && "SubclassData contains only 16 bits");
if (On)
setValueSubclassData(getSubclassDataFromValue() | (1 << Bit));
else
setValueSubclassData(getSubclassDataFromValue() & ~(1 << Bit));
}
void Function::setEntryCount(uint64_t Count,
const DenseSet<GlobalValue::GUID> *S) {
MDBuilder MDB(getContext());
setMetadata(LLVMContext::MD_prof, MDB.createFunctionEntryCount(Count, S));
}
Optional<uint64_t> Function::getEntryCount() const {
MDNode *MD = getMetadata(LLVMContext::MD_prof);
if (MD && MD->getOperand(0))
if (MDString *MDS = dyn_cast<MDString>(MD->getOperand(0)))
if (MDS->getString().equals("function_entry_count")) {
ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(1));
uint64_t Count = CI->getValue().getZExtValue();
if (Count == 0)
return None;
return Count;
}
return None;
}
DenseSet<GlobalValue::GUID> Function::getImportGUIDs() const {
DenseSet<GlobalValue::GUID> R;
if (MDNode *MD = getMetadata(LLVMContext::MD_prof))
if (MDString *MDS = dyn_cast<MDString>(MD->getOperand(0)))
if (MDS->getString().equals("function_entry_count"))
for (unsigned i = 2; i < MD->getNumOperands(); i++)
R.insert(mdconst::extract<ConstantInt>(MD->getOperand(i))
->getValue()
.getZExtValue());
return R;
}
void Function::setSectionPrefix(StringRef Prefix) {
MDBuilder MDB(getContext());
setMetadata(LLVMContext::MD_section_prefix,
MDB.createFunctionSectionPrefix(Prefix));
}
Optional<StringRef> Function::getSectionPrefix() const {
if (MDNode *MD = getMetadata(LLVMContext::MD_section_prefix)) {
assert(dyn_cast<MDString>(MD->getOperand(0))
->getString()
.equals("function_section_prefix") &&
"Metadata not match");
return dyn_cast<MDString>(MD->getOperand(1))->getString();
}
return None;
}