//===- Scope.h - Scope interface --------------------------------*- 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 file defines the Scope interface.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_SEMA_SCOPE_H
#define LLVM_CLANG_SEMA_SCOPE_H
#include "clang/AST/Decl.h"
#include "clang/Basic/Diagnostic.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/iterator_range.h"
#include <cassert>
#include <optional>
namespace llvm {
class raw_ostream;
} // namespace llvm
namespace clang {
class Decl;
class DeclContext;
class UsingDirectiveDecl;
class VarDecl;
/// Scope - A scope is a transient data structure that is used while parsing the
/// program. It assists with resolving identifiers to the appropriate
/// declaration.
class Scope {
public:
/// ScopeFlags - These are bitfields that are or'd together when creating a
/// scope, which defines the sorts of things the scope contains.
enum ScopeFlags {
/// This indicates that the scope corresponds to a function, which
/// means that labels are set here.
FnScope = 0x01,
/// This is a while, do, switch, for, etc that can have break
/// statements embedded into it.
BreakScope = 0x02,
/// This is a while, do, for, which can have continue statements
/// embedded into it.
ContinueScope = 0x04,
/// This is a scope that can contain a declaration. Some scopes
/// just contain loop constructs but don't contain decls.
DeclScope = 0x08,
/// The controlling scope in a if/switch/while/for statement.
ControlScope = 0x10,
/// The scope of a struct/union/class definition.
ClassScope = 0x20,
/// This is a scope that corresponds to a block/closure object.
/// Blocks serve as top-level scopes for some objects like labels, they
/// also prevent things like break and continue. BlockScopes always have
/// the FnScope and DeclScope flags set as well.
BlockScope = 0x40,
/// This is a scope that corresponds to the
/// template parameters of a C++ template. Template parameter
/// scope starts at the 'template' keyword and ends when the
/// template declaration ends.
TemplateParamScope = 0x80,
/// This is a scope that corresponds to the
/// parameters within a function prototype.
FunctionPrototypeScope = 0x100,
/// This is a scope that corresponds to the parameters within
/// a function prototype for a function declaration (as opposed to any
/// other kind of function declarator). Always has FunctionPrototypeScope
/// set as well.
FunctionDeclarationScope = 0x200,
/// This is a scope that corresponds to the Objective-C
/// \@catch statement.
AtCatchScope = 0x400,
/// This scope corresponds to an Objective-C method body.
/// It always has FnScope and DeclScope set as well.
ObjCMethodScope = 0x800,
/// This is a scope that corresponds to a switch statement.
SwitchScope = 0x1000,
/// This is the scope of a C++ try statement.
TryScope = 0x2000,
/// This is the scope for a function-level C++ try or catch scope.
FnTryCatchScope = 0x4000,
/// This is the scope of OpenMP executable directive.
OpenMPDirectiveScope = 0x8000,
/// This is the scope of some OpenMP loop directive.
OpenMPLoopDirectiveScope = 0x10000,
/// This is the scope of some OpenMP simd directive.
/// For example, it is used for 'omp simd', 'omp for simd'.
/// This flag is propagated to children scopes.
OpenMPSimdDirectiveScope = 0x20000,
/// This scope corresponds to an enum.
EnumScope = 0x40000,
/// This scope corresponds to an SEH try.
SEHTryScope = 0x80000,
/// This scope corresponds to an SEH except.
SEHExceptScope = 0x100000,
/// We are currently in the filter expression of an SEH except block.
SEHFilterScope = 0x200000,
/// This is a compound statement scope.
CompoundStmtScope = 0x400000,
/// We are between inheritance colon and the real class/struct definition
/// scope.
ClassInheritanceScope = 0x800000,
/// This is the scope of a C++ catch statement.
CatchScope = 0x1000000,
/// This is a scope in which a condition variable is currently being
/// parsed. If such a scope is a ContinueScope, it's invalid to jump to the
/// continue block from here.
ConditionVarScope = 0x2000000,
/// This is a scope of some OpenMP directive with
/// order clause which specifies concurrent
OpenMPOrderClauseScope = 0x4000000,
};
private:
/// The parent scope for this scope. This is null for the translation-unit
/// scope.
Scope *AnyParent;
/// Flags - This contains a set of ScopeFlags, which indicates how the scope
/// interrelates with other control flow statements.
unsigned Flags;
/// Depth - This is the depth of this scope. The translation-unit scope has
/// depth 0.
unsigned short Depth;
/// Declarations with static linkage are mangled with the number of
/// scopes seen as a component.
unsigned short MSLastManglingNumber;
unsigned short MSCurManglingNumber;
/// PrototypeDepth - This is the number of function prototype scopes
/// enclosing this scope, including this scope.
unsigned short PrototypeDepth;
/// PrototypeIndex - This is the number of parameters currently
/// declared in this scope.
unsigned short PrototypeIndex;
/// FnParent - If this scope has a parent scope that is a function body, this
/// pointer is non-null and points to it. This is used for label processing.
Scope *FnParent;
Scope *MSLastManglingParent;
/// BreakParent/ContinueParent - This is a direct link to the innermost
/// BreakScope/ContinueScope which contains the contents of this scope
/// for control flow purposes (and might be this scope itself), or null
/// if there is no such scope.
Scope *BreakParent, *ContinueParent;
/// BlockParent - This is a direct link to the immediately containing
/// BlockScope if this scope is not one, or null if there is none.
Scope *BlockParent;
/// TemplateParamParent - This is a direct link to the
/// immediately containing template parameter scope. In the
/// case of nested templates, template parameter scopes can have
/// other template parameter scopes as parents.
Scope *TemplateParamParent;
/// DeclsInScope - This keeps track of all declarations in this scope. When
/// the declaration is added to the scope, it is set as the current
/// declaration for the identifier in the IdentifierTable. When the scope is
/// popped, these declarations are removed from the IdentifierTable's notion
/// of current declaration. It is up to the current Action implementation to
/// implement these semantics.
using DeclSetTy = llvm::SmallPtrSet<Decl *, 32>;
DeclSetTy DeclsInScope;
/// The DeclContext with which this scope is associated. For
/// example, the entity of a class scope is the class itself, the
/// entity of a function scope is a function, etc.
DeclContext *Entity;
using UsingDirectivesTy = SmallVector<UsingDirectiveDecl *, 2>;
UsingDirectivesTy UsingDirectives;
/// Used to determine if errors occurred in this scope.
DiagnosticErrorTrap ErrorTrap;
/// A single NRVO candidate variable in this scope.
/// There are three possible values:
/// 1) pointer to VarDecl that denotes NRVO candidate itself.
/// 2) nullptr value means that NRVO is not allowed in this scope
/// (e.g. return a function parameter).
/// 3) std::nullopt value means that there is no NRVO candidate in this scope
/// (i.e. there are no return statements in this scope).
std::optional<VarDecl *> NRVO;
/// Represents return slots for NRVO candidates in the current scope.
/// If a variable is present in this set, it means that a return slot is
/// available for this variable in the current scope.
llvm::SmallPtrSet<VarDecl *, 8> ReturnSlots;
void setFlags(Scope *Parent, unsigned F);
public:
Scope(Scope *Parent, unsigned ScopeFlags, DiagnosticsEngine &Diag)
: ErrorTrap(Diag) {
Init(Parent, ScopeFlags);
}
/// getFlags - Return the flags for this scope.
unsigned getFlags() const { return Flags; }
void setFlags(unsigned F) { setFlags(getParent(), F); }
/// isBlockScope - Return true if this scope correspond to a closure.
bool isBlockScope() const { return Flags & BlockScope; }
/// getParent - Return the scope that this is nested in.
const Scope *getParent() const { return AnyParent; }
Scope *getParent() { return AnyParent; }
/// getFnParent - Return the closest scope that is a function body.
const Scope *getFnParent() const { return FnParent; }
Scope *getFnParent() { return FnParent; }
const Scope *getMSLastManglingParent() const {
return MSLastManglingParent;
}
Scope *getMSLastManglingParent() { return MSLastManglingParent; }
/// getContinueParent - Return the closest scope that a continue statement
/// would be affected by.
Scope *getContinueParent() {
return ContinueParent;
}
const Scope *getContinueParent() const {
return const_cast<Scope*>(this)->getContinueParent();
}
// Set whether we're in the scope of a condition variable, where 'continue'
// is disallowed despite being a continue scope.
void setIsConditionVarScope(bool InConditionVarScope) {
Flags = (Flags & ~ConditionVarScope) |
(InConditionVarScope ? ConditionVarScope : 0);
}
bool isConditionVarScope() const {
return Flags & ConditionVarScope;
}
/// getBreakParent - Return the closest scope that a break statement
/// would be affected by.
Scope *getBreakParent() {
return BreakParent;
}
const Scope *getBreakParent() const {
return const_cast<Scope*>(this)->getBreakParent();
}
Scope *getBlockParent() { return BlockParent; }
const Scope *getBlockParent() const { return BlockParent; }
Scope *getTemplateParamParent() { return TemplateParamParent; }
const Scope *getTemplateParamParent() const { return TemplateParamParent; }
/// Returns the depth of this scope. The translation-unit has scope depth 0.
unsigned getDepth() const { return Depth; }
/// Returns the number of function prototype scopes in this scope
/// chain.
unsigned getFunctionPrototypeDepth() const {
return PrototypeDepth;
}
/// Return the number of parameters declared in this function
/// prototype, increasing it by one for the next call.
unsigned getNextFunctionPrototypeIndex() {
assert(isFunctionPrototypeScope());
return PrototypeIndex++;
}
using decl_range = llvm::iterator_range<DeclSetTy::iterator>;
decl_range decls() const {
return decl_range(DeclsInScope.begin(), DeclsInScope.end());
}
bool decl_empty() const { return DeclsInScope.empty(); }
void AddDecl(Decl *D) {
if (auto *VD = dyn_cast<VarDecl>(D))
if (!isa<ParmVarDecl>(VD))
ReturnSlots.insert(VD);
DeclsInScope.insert(D);
}
void RemoveDecl(Decl *D) { DeclsInScope.erase(D); }
void incrementMSManglingNumber() {
if (Scope *MSLMP = getMSLastManglingParent()) {
MSLMP->MSLastManglingNumber += 1;
MSCurManglingNumber += 1;
}
}
void decrementMSManglingNumber() {
if (Scope *MSLMP = getMSLastManglingParent()) {
MSLMP->MSLastManglingNumber -= 1;
MSCurManglingNumber -= 1;
}
}
unsigned getMSLastManglingNumber() const {
if (const Scope *MSLMP = getMSLastManglingParent())
return MSLMP->MSLastManglingNumber;
return 1;
}
unsigned getMSCurManglingNumber() const {
return MSCurManglingNumber;
}
/// isDeclScope - Return true if this is the scope that the specified decl is
/// declared in.
bool isDeclScope(const Decl *D) const { return DeclsInScope.contains(D); }
/// Get the entity corresponding to this scope.
DeclContext *getEntity() const {
return isTemplateParamScope() ? nullptr : Entity;
}
/// Get the DeclContext in which to continue unqualified lookup after a
/// lookup in this scope.
DeclContext *getLookupEntity() const { return Entity; }
void setEntity(DeclContext *E) {
assert(!isTemplateParamScope() &&
"entity associated with template param scope");
Entity = E;
}
void setLookupEntity(DeclContext *E) { Entity = E; }
/// Determine whether any unrecoverable errors have occurred within this
/// scope. Note that this may return false even if the scope contains invalid
/// declarations or statements, if the errors for those invalid constructs
/// were suppressed because some prior invalid construct was referenced.
bool hasUnrecoverableErrorOccurred() const {
return ErrorTrap.hasUnrecoverableErrorOccurred();
}
/// isFunctionScope() - Return true if this scope is a function scope.
bool isFunctionScope() const { return getFlags() & Scope::FnScope; }
/// isClassScope - Return true if this scope is a class/struct/union scope.
bool isClassScope() const { return getFlags() & Scope::ClassScope; }
/// Determines whether this scope is between inheritance colon and the real
/// class/struct definition.
bool isClassInheritanceScope() const {
return getFlags() & Scope::ClassInheritanceScope;
}
/// isInCXXInlineMethodScope - Return true if this scope is a C++ inline
/// method scope or is inside one.
bool isInCXXInlineMethodScope() const {
if (const Scope *FnS = getFnParent()) {
assert(FnS->getParent() && "TUScope not created?");
return FnS->getParent()->isClassScope();
}
return false;
}
/// isInObjcMethodScope - Return true if this scope is, or is contained in, an
/// Objective-C method body. Note that this method is not constant time.
bool isInObjcMethodScope() const {
for (const Scope *S = this; S; S = S->getParent()) {
// If this scope is an objc method scope, then we succeed.
if (S->getFlags() & ObjCMethodScope)
return true;
}
return false;
}
/// isInObjcMethodOuterScope - Return true if this scope is an
/// Objective-C method outer most body.
bool isInObjcMethodOuterScope() const {
if (const Scope *S = this) {
// If this scope is an objc method scope, then we succeed.
if (S->getFlags() & ObjCMethodScope)
return true;
}
return false;
}
/// isTemplateParamScope - Return true if this scope is a C++
/// template parameter scope.
bool isTemplateParamScope() const {
return getFlags() & Scope::TemplateParamScope;
}
/// isFunctionPrototypeScope - Return true if this scope is a
/// function prototype scope.
bool isFunctionPrototypeScope() const {
return getFlags() & Scope::FunctionPrototypeScope;
}
/// isFunctionDeclarationScope - Return true if this scope is a
/// function prototype scope.
bool isFunctionDeclarationScope() const {
return getFlags() & Scope::FunctionDeclarationScope;
}
/// isAtCatchScope - Return true if this scope is \@catch.
bool isAtCatchScope() const {
return getFlags() & Scope::AtCatchScope;
}
/// isCatchScope - Return true if this scope is a C++ catch statement.
bool isCatchScope() const { return getFlags() & Scope::CatchScope; }
/// isSwitchScope - Return true if this scope is a switch scope.
bool isSwitchScope() const {
for (const Scope *S = this; S; S = S->getParent()) {
if (S->getFlags() & Scope::SwitchScope)
return true;
else if (S->getFlags() & (Scope::FnScope | Scope::ClassScope |
Scope::BlockScope | Scope::TemplateParamScope |
Scope::FunctionPrototypeScope |
Scope::AtCatchScope | Scope::ObjCMethodScope))
return false;
}
return false;
}
/// Determines whether this scope is the OpenMP directive scope
bool isOpenMPDirectiveScope() const {
return (getFlags() & Scope::OpenMPDirectiveScope);
}
/// Determine whether this scope is some OpenMP loop directive scope
/// (for example, 'omp for', 'omp simd').
bool isOpenMPLoopDirectiveScope() const {
if (getFlags() & Scope::OpenMPLoopDirectiveScope) {
assert(isOpenMPDirectiveScope() &&
"OpenMP loop directive scope is not a directive scope");
return true;
}
return false;
}
/// Determine whether this scope is (or is nested into) some OpenMP
/// loop simd directive scope (for example, 'omp simd', 'omp for simd').
bool isOpenMPSimdDirectiveScope() const {
return getFlags() & Scope::OpenMPSimdDirectiveScope;
}
/// Determine whether this scope is a loop having OpenMP loop
/// directive attached.
bool isOpenMPLoopScope() const {
const Scope *P = getParent();
return P && P->isOpenMPLoopDirectiveScope();
}
/// Determine whether this scope is some OpenMP directive with
/// order clause which specifies concurrent scope.
bool isOpenMPOrderClauseScope() const {
return getFlags() & Scope::OpenMPOrderClauseScope;
}
/// Determine whether this scope is a while/do/for statement, which can have
/// continue statements embedded into it.
bool isContinueScope() const {
return getFlags() & ScopeFlags::ContinueScope;
}
/// Determine whether this scope is a C++ 'try' block.
bool isTryScope() const { return getFlags() & Scope::TryScope; }
/// Determine whether this scope is a function-level C++ try or catch scope.
bool isFnTryCatchScope() const {
return getFlags() & ScopeFlags::FnTryCatchScope;
}
/// Determine whether this scope is a SEH '__try' block.
bool isSEHTryScope() const { return getFlags() & Scope::SEHTryScope; }
/// Determine whether this scope is a SEH '__except' block.
bool isSEHExceptScope() const { return getFlags() & Scope::SEHExceptScope; }
/// Determine whether this scope is a compound statement scope.
bool isCompoundStmtScope() const {
return getFlags() & Scope::CompoundStmtScope;
}
/// Determine whether this scope is a controlling scope in a
/// if/switch/while/for statement.
bool isControlScope() const { return getFlags() & Scope::ControlScope; }
/// Returns if rhs has a higher scope depth than this.
///
/// The caller is responsible for calling this only if one of the two scopes
/// is an ancestor of the other.
bool Contains(const Scope& rhs) const { return Depth < rhs.Depth; }
/// containedInPrototypeScope - Return true if this or a parent scope
/// is a FunctionPrototypeScope.
bool containedInPrototypeScope() const;
void PushUsingDirective(UsingDirectiveDecl *UDir) {
UsingDirectives.push_back(UDir);
}
using using_directives_range =
llvm::iterator_range<UsingDirectivesTy::iterator>;
using_directives_range using_directives() {
return using_directives_range(UsingDirectives.begin(),
UsingDirectives.end());
}
void updateNRVOCandidate(VarDecl *VD);
void applyNRVO();
/// Init - This is used by the parser to implement scope caching.
void Init(Scope *parent, unsigned flags);
/// Sets up the specified scope flags and adjusts the scope state
/// variables accordingly.
void AddFlags(unsigned Flags);
void dumpImpl(raw_ostream &OS) const;
void dump() const;
};
} // namespace clang
#endif // LLVM_CLANG_SEMA_SCOPE_H