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//===-- llvm/GlobalObject.h - Class to represent global objects -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This represents an independent object. That is, a function or a global
// variable, but not an alias.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_GLOBALOBJECT_H
#define LLVM_IR_GLOBALOBJECT_H
#include "llvm/ADT/StringRef.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Alignment.h"
namespace llvm {
class Comdat;
class Metadata;
class GlobalObject : public GlobalValue {
public:
// VCallVisibility - values for visibility metadata attached to vtables. This
// describes the scope in which a virtual call could end up being dispatched
// through this vtable.
enum VCallVisibility {
// Type is potentially visible to external code.
VCallVisibilityPublic = 0,
// Type is only visible to code which will be in the current Module after
// LTO internalization.
VCallVisibilityLinkageUnit = 1,
// Type is only visible to code in the current Module.
VCallVisibilityTranslationUnit = 2,
};
protected:
GlobalObject(Type *Ty, ValueTy VTy, Use *Ops, unsigned NumOps,
LinkageTypes Linkage, const Twine &Name,
unsigned AddressSpace = 0)
: GlobalValue(Ty, VTy, Ops, NumOps, Linkage, Name, AddressSpace),
ObjComdat(nullptr) {
setGlobalValueSubClassData(0);
}
~GlobalObject();
Comdat *ObjComdat;
enum {
LastAlignmentBit = 5,
HasSectionHashEntryBit,
GlobalObjectBits,
};
static const unsigned GlobalObjectSubClassDataBits =
GlobalValueSubClassDataBits - GlobalObjectBits;
private:
static const unsigned AlignmentBits = LastAlignmentBit + 1;
static const unsigned AlignmentMask = (1 << AlignmentBits) - 1;
static const unsigned GlobalObjectMask = (1 << GlobalObjectBits) - 1;
public:
GlobalObject(const GlobalObject &) = delete;
/// FIXME: Remove this function once transition to Align is over.
uint64_t getAlignment() const {
MaybeAlign Align = getAlign();
return Align ? Align->value() : 0;
}
/// Returns the alignment of the given variable or function.
///
/// Note that for functions this is the alignment of the code, not the
/// alignment of a function pointer.
MaybeAlign getAlign() const {
unsigned Data = getGlobalValueSubClassData();
unsigned AlignmentData = Data & AlignmentMask;
return decodeMaybeAlign(AlignmentData);
}
void setAlignment(MaybeAlign Align);
unsigned getGlobalObjectSubClassData() const {
unsigned ValueData = getGlobalValueSubClassData();
return ValueData >> GlobalObjectBits;
}
void setGlobalObjectSubClassData(unsigned Val) {
unsigned OldData = getGlobalValueSubClassData();
setGlobalValueSubClassData((OldData & GlobalObjectMask) |
(Val << GlobalObjectBits));
assert(getGlobalObjectSubClassData() == Val && "representation error");
}
/// Check if this global has a custom object file section.
///
/// This is more efficient than calling getSection() and checking for an empty
/// string.
bool hasSection() const {
return getGlobalValueSubClassData() & (1 << HasSectionHashEntryBit);
}
/// Get the custom section of this global if it has one.
///
/// If this global does not have a custom section, this will be empty and the
/// default object file section (.text, .data, etc) will be used.
StringRef getSection() const {
return hasSection() ? getSectionImpl() : StringRef();
}
/// Change the section for this global.
///
/// Setting the section to the empty string tells LLVM to choose an
/// appropriate default object file section.
void setSection(StringRef S);
bool hasComdat() const { return getComdat() != nullptr; }
const Comdat *getComdat() const { return ObjComdat; }
Comdat *getComdat() { return ObjComdat; }
void setComdat(Comdat *C);
using Value::addMetadata;
using Value::clearMetadata;
using Value::eraseMetadata;
using Value::getAllMetadata;
using Value::getMetadata;
using Value::hasMetadata;
using Value::setMetadata;
/// Copy metadata from Src, adjusting offsets by Offset.
void copyMetadata(const GlobalObject *Src, unsigned Offset);
void addTypeMetadata(unsigned Offset, Metadata *TypeID);
void setVCallVisibilityMetadata(VCallVisibility Visibility);
VCallVisibility getVCallVisibility() const;
/// Returns true if the alignment of the value can be unilaterally
/// increased.
///
/// Note that for functions this is the alignment of the code, not the
/// alignment of a function pointer.
bool canIncreaseAlignment() const;
protected:
void copyAttributesFrom(const GlobalObject *Src);
public:
// Methods for support type inquiry through isa, cast, and dyn_cast:
static bool classof(const Value *V) {
return V->getValueID() == Value::FunctionVal ||
V->getValueID() == Value::GlobalVariableVal ||
V->getValueID() == Value::GlobalIFuncVal;
}
private:
void setGlobalObjectFlag(unsigned Bit, bool Val) {
unsigned Mask = 1 << Bit;
setGlobalValueSubClassData((~Mask & getGlobalValueSubClassData()) |
(Val ? Mask : 0u));
}
StringRef getSectionImpl() const;
};
} // end namespace llvm
#endif // LLVM_IR_GLOBALOBJECT_H
|
