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//===--- SILGlobalVariable.h - Defines SILGlobalVariable class --*- C++ -*-===//
// This source file is part of the open source project
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
// See for license information
// See for the list of Swift project authors
// This file defines the SILGlobalVariable class.
#include "swift/SIL/SILLinkage.h"
#include "swift/SIL/SILLocation.h"
#include "swift/SIL/SILBasicBlock.h"
#include "swift/SIL/SILType.h"
#include "llvm/ADT/ilist_node.h"
#include "llvm/ADT/ilist.h"
namespace swift {
class ASTContext;
class SILFunction;
class SILInstruction;
class SILModule;
class VarDecl;
/// A global variable that has been referenced in SIL.
class SILGlobalVariable
: public llvm::ilist_node<SILGlobalVariable>,
public SILAllocated<SILGlobalVariable>
using const_iterator = SILBasicBlock::const_iterator;
friend class SILModule;
friend class SILBuilder;
/// The SIL module that the global variable belongs to.
SILModule &Module;
/// The mangled name of the variable, which will be propagated to the
/// binary. A pointer into the module's lookup table.
StringRef Name;
/// The lowered type of the variable.
SILType LoweredType;
/// The SIL location of the variable, which provides a link back to the AST.
/// The variable only gets a location after it's been emitted.
const SILLocation Location;
/// The linkage of the global variable.
unsigned Linkage : NumSILLinkageBits;
/// The global variable's serialized attribute.
/// Serialized means that the variable can be "inlined" into another module.
/// Currently this flag is set for all global variables in the stdlib.
unsigned Serialized : 1;
/// Whether this is a 'let' property, which can only be initialized
/// once (either in its declaration, or once later), making it immutable.
unsigned IsLet : 1;
/// Whether or not this is a declaration.
unsigned IsDeclaration : 1;
/// Whether or not there is a valid SILLocation.
unsigned HasLocation : 1;
/// The VarDecl associated with this SILGlobalVariable. Must by nonnull for
/// language-level global variables.
VarDecl *VDecl;
/// If this block is not empty, the global variable has a static initializer.
/// The last instruction of this block is the top-level value of the static
/// initializer.
/// The block is just used as a container for the instructions. So the
/// instructions still have a parent SILBasicBlock (but no parent function).
/// It would be somehow cleaner to just store an instruction list here and
/// make the SILGlobalVariable the parent pointer of the instructions.
SILBasicBlock StaticInitializerBlock;
SILGlobalVariable(SILModule &M, SILLinkage linkage,
IsSerialized_t IsSerialized,
StringRef mangledName, SILType loweredType,
Optional<SILLocation> loc, VarDecl *decl);
static SILGlobalVariable *create(SILModule &Module, SILLinkage Linkage,
IsSerialized_t IsSerialized,
StringRef MangledName, SILType LoweredType,
Optional<SILLocation> Loc = None,
VarDecl *Decl = nullptr);
SILModule &getModule() const { return Module; }
SILType getLoweredType() const { return LoweredType; }
CanSILFunctionType getLoweredFunctionType() const {
return LoweredType.castTo<SILFunctionType>();
SILType getLoweredTypeInContext(TypeExpansionContext context) const;
getLoweredFunctionTypeInContext(TypeExpansionContext context) const {
return getLoweredTypeInContext(context).castTo<SILFunctionType>();
StringRef getName() const { return Name; }
void setDeclaration(bool isD) { IsDeclaration = isD; }
/// True if this is a definition of the variable.
bool isDefinition() const { return !IsDeclaration; }
/// Get this function's linkage attribute.
SILLinkage getLinkage() const { return SILLinkage(Linkage); }
void setLinkage(SILLinkage linkage) { Linkage = unsigned(linkage); }
/// Get this global variable's serialized attribute.
IsSerialized_t isSerialized() const;
void setSerialized(IsSerialized_t isSerialized);
/// Is this an immutable 'let' property?
bool isLet() const { return IsLet; }
void setLet(bool isLet) { IsLet = isLet; }
VarDecl *getDecl() const { return VDecl; }
/// Check if the function has a location.
/// FIXME: All functions should have locations, so this method should not be
/// necessary.
bool hasLocation() const {
return HasLocation;
/// Get the source location of the function.
SILLocation getLocation() const {
return Location;
/// Returns the value of the static initializer or null if the global has no
/// static initializer.
SILInstruction *getStaticInitializerValue();
/// Returns true if the global is a statically initialized heap object.
bool isInitializedObject() {
return dyn_cast_or_null<ObjectInst>(getStaticInitializerValue()) != nullptr;
const_iterator begin() const { return StaticInitializerBlock.begin(); }
const_iterator end() const { return StaticInitializerBlock.end(); }
/// Returns true if \p I is a valid instruction to be contained in the
/// static initializer.
static bool isValidStaticInitializerInst(const SILInstruction *I,
SILModule &M);
/// Returns the usub_with_overflow builtin if \p TE extracts the result of
/// such a subtraction, which is required to have an integer_literal as right
/// operand.
static BuiltinInst *getOffsetSubtract(const TupleExtractInst *TE, SILModule &M);
void dropAllReferences() {
/// Return whether this variable corresponds to a Clang node.
bool hasClangNode() const;
/// Return the Clang node associated with this variable if it has one.
ClangNode getClangNode() const;
const clang::Decl *getClangDecl() const;
// Miscellaneous
/// verify - Run the IR verifier to make sure that the variable follows
/// invariants.
void verify() const;
/// Pretty-print the variable.
void dump(bool Verbose) const;
/// Pretty-print the variable.
/// This is a separate entry point for ease of debugging.
void dump() const LLVM_ATTRIBUTE_USED;
/// Pretty-print the variable to the designated stream as a 'sil_global'
/// definition.
/// \param Verbose In verbose mode, print the SIL locations.
void print(raw_ostream &OS, bool Verbose = false) const;
/// Pretty-print the variable name using SIL syntax,
/// '@var_mangled_name'.
void printName(raw_ostream &OS) const;
ASTContext &getASTContext() const;
inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
const SILGlobalVariable &F) {
return OS;
} // end swift namespace
// ilist_traits for SILGlobalVariable
namespace llvm {
template <>
struct ilist_traits<::swift::SILGlobalVariable> :
public ilist_node_traits<::swift::SILGlobalVariable> {
using SILGlobalVariable = ::swift::SILGlobalVariable;
static void deleteNode(SILGlobalVariable *V) { V->~SILGlobalVariable(); }
void createNode(const SILGlobalVariable &);
} // end llvm namespace
// Utilities for verification and optimization.
namespace swift {
/// Given an addressor, AddrF, return the global variable being addressed, or
/// return nullptr if the addressor isn't a recognized pattern.
SILGlobalVariable *getVariableOfGlobalInit(SILFunction *AddrF);
/// Return the callee of a once call.
SILFunction *getCalleeOfOnceCall(BuiltinInst *BI);
/// Helper for getVariableOfGlobalInit(), so GlobalOpts can deeply inspect and
/// rewrite the initialization pattern.
/// Given an addressor, AddrF, find the call to the global initializer if
/// present, otherwise return null. If an initializer is returned, then
/// `CallToOnce` is initialized to the corresponding builtin "once" call.
SILFunction *findInitializer(SILFunction *AddrF, BuiltinInst *&CallToOnce);
/// Helper for getVariableOfGlobalInit(), so GlobalOpts can deeply inspect and
/// rewrite the initialization pattern.
/// Given a global initializer, InitFunc, return the GlobalVariable that it
/// statically initializes or return nullptr if it isn't an obvious static
/// initializer. If a global variable is returned, InitVal is initialized to the
/// the instruction producing the global's initial value.
SILGlobalVariable *getVariableOfStaticInitializer(
SILFunction *InitFunc, SingleValueInstruction *&InitVal);
} // namespace swift