r367254 - When determining whether a lambda-expression is implicitly constexpr,
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Mon Jul 29 12:59:46 PDT 2019
Author: rsmith
Date: Mon Jul 29 12:59:45 2019
New Revision: 367254
URL: http://llvm.org/viewvc/llvm-project?rev=367254&view=rev
Log:
When determining whether a lambda-expression is implicitly constexpr,
check the formal rules rather than seeing if the normal checks produce a
diagnostic.
This fixes the handling of C++2a extensions in lambdas in C++17 mode,
as well as some corner cases in earlier language modes where we issue
diagnostics for things other than not satisfying the formal constexpr
requirements.
Modified:
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/lib/Sema/SemaDeclCXX.cpp
cfe/trunk/lib/Sema/SemaLambda.cpp
cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp
cfe/trunk/test/SemaCXX/cxx1z-constexpr-lambdas.cpp
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=367254&r1=367253&r2=367254&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Mon Jul 29 12:59:45 2019
@@ -2076,8 +2076,16 @@ public:
bool &AddToScope);
bool AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD);
- bool CheckConstexprFunctionDecl(const FunctionDecl *FD);
- bool CheckConstexprFunctionBody(const FunctionDecl *FD, Stmt *Body);
+ enum class CheckConstexprKind {
+ /// Diagnose issues that are non-constant or that are extensions.
+ Diagnose,
+ /// Identify whether this function satisfies the formal rules for constexpr
+ /// functions in the current lanugage mode (with no extensions).
+ CheckValid
+ };
+
+ bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
+ CheckConstexprKind Kind);
void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
void FindHiddenVirtualMethods(CXXMethodDecl *MD,
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=367254&r1=367253&r2=367254&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Mon Jul 29 12:59:45 2019
@@ -13532,8 +13532,7 @@ Decl *Sema::ActOnFinishFunctionBody(Decl
}
if (!IsInstantiation && FD && FD->isConstexpr() && !FD->isInvalidDecl() &&
- (!CheckConstexprFunctionDecl(FD) ||
- !CheckConstexprFunctionBody(FD, Body)))
+ !CheckConstexprFunctionDefinition(FD, CheckConstexprKind::Diagnose))
FD->setInvalidDecl();
if (FD && FD->hasAttr<NakedAttr>()) {
Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=367254&r1=367253&r2=367254&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Mon Jul 29 12:59:45 2019
@@ -1569,11 +1569,34 @@ void Sema::CheckCXXDefaultArguments(Func
}
}
+/// Check that the given type is a literal type. Issue a diagnostic if not,
+/// if Kind is Diagnose.
+/// \return \c true if a problem has been found (and optionally diagnosed).
+template <typename... Ts>
+static bool CheckLiteralType(Sema &SemaRef, Sema::CheckConstexprKind Kind,
+ SourceLocation Loc, QualType T, unsigned DiagID,
+ Ts &&...DiagArgs) {
+ if (T->isDependentType())
+ return false;
+
+ switch (Kind) {
+ case Sema::CheckConstexprKind::Diagnose:
+ return SemaRef.RequireLiteralType(Loc, T, DiagID,
+ std::forward<Ts>(DiagArgs)...);
+
+ case Sema::CheckConstexprKind::CheckValid:
+ return !T->isLiteralType(SemaRef.Context);
+ }
+
+ llvm_unreachable("unknown CheckConstexprKind");
+}
+
// CheckConstexprParameterTypes - Check whether a function's parameter types
// are all literal types. If so, return true. If not, produce a suitable
// diagnostic and return false.
static bool CheckConstexprParameterTypes(Sema &SemaRef,
- const FunctionDecl *FD) {
+ const FunctionDecl *FD,
+ Sema::CheckConstexprKind Kind) {
unsigned ArgIndex = 0;
const FunctionProtoType *FT = FD->getType()->getAs<FunctionProtoType>();
for (FunctionProtoType::param_type_iterator i = FT->param_type_begin(),
@@ -1581,11 +1604,10 @@ static bool CheckConstexprParameterTypes
i != e; ++i, ++ArgIndex) {
const ParmVarDecl *PD = FD->getParamDecl(ArgIndex);
SourceLocation ParamLoc = PD->getLocation();
- if (!(*i)->isDependentType() &&
- SemaRef.RequireLiteralType(
- ParamLoc, *i, diag::err_constexpr_non_literal_param, ArgIndex + 1,
- PD->getSourceRange(), isa<CXXConstructorDecl>(FD),
- FD->isConsteval()))
+ if (CheckLiteralType(SemaRef, Kind, ParamLoc, *i,
+ diag::err_constexpr_non_literal_param, ArgIndex + 1,
+ PD->getSourceRange(), isa<CXXConstructorDecl>(FD),
+ FD->isConsteval()))
return false;
}
return true;
@@ -1605,13 +1627,18 @@ static unsigned getRecordDiagFromTagKind
}
}
-// CheckConstexprFunctionDecl - Check whether a function declaration satisfies
-// the requirements of a constexpr function definition or a constexpr
-// constructor definition. If so, return true. If not, produce appropriate
-// diagnostics and return false.
+static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl,
+ Stmt *Body,
+ Sema::CheckConstexprKind Kind);
+
+// Check whether a function declaration satisfies the requirements of a
+// constexpr function definition or a constexpr constructor definition. If so,
+// return true. If not, produce appropriate diagnostics (unless asked not to by
+// Kind) and return false.
//
// This implements C++11 [dcl.constexpr]p3,4, as amended by DR1360.
-bool Sema::CheckConstexprFunctionDecl(const FunctionDecl *NewFD) {
+bool Sema::CheckConstexprFunctionDefinition(const FunctionDecl *NewFD,
+ CheckConstexprKind Kind) {
const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
if (MD && MD->isInstance()) {
// C++11 [dcl.constexpr]p4:
@@ -1623,6 +1650,9 @@ bool Sema::CheckConstexprFunctionDecl(co
// functions.
const CXXRecordDecl *RD = MD->getParent();
if (RD->getNumVBases()) {
+ if (Kind == CheckConstexprKind::CheckValid)
+ return false;
+
Diag(NewFD->getLocation(), diag::err_constexpr_virtual_base)
<< isa<CXXConstructorDecl>(NewFD)
<< getRecordDiagFromTagKind(RD->getTagKind()) << RD->getNumVBases();
@@ -1641,8 +1671,12 @@ bool Sema::CheckConstexprFunctionDecl(co
const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(NewFD);
if (Method && Method->isVirtual()) {
if (getLangOpts().CPlusPlus2a) {
- Diag(Method->getLocation(), diag::warn_cxx17_compat_constexpr_virtual);
+ if (Kind == CheckConstexprKind::Diagnose)
+ Diag(Method->getLocation(), diag::warn_cxx17_compat_constexpr_virtual);
} else {
+ if (Kind == CheckConstexprKind::CheckValid)
+ return false;
+
Method = Method->getCanonicalDecl();
Diag(Method->getLocation(), diag::err_constexpr_virtual);
@@ -1660,18 +1694,20 @@ bool Sema::CheckConstexprFunctionDecl(co
// - its return type shall be a literal type;
QualType RT = NewFD->getReturnType();
- if (!RT->isDependentType() &&
- RequireLiteralType(NewFD->getLocation(), RT,
- diag::err_constexpr_non_literal_return,
- NewFD->isConsteval()))
+ if (CheckLiteralType(*this, Kind, NewFD->getLocation(), RT,
+ diag::err_constexpr_non_literal_return,
+ NewFD->isConsteval()))
return false;
}
// - each of its parameter types shall be a literal type;
- if (!CheckConstexprParameterTypes(*this, NewFD))
+ if (!CheckConstexprParameterTypes(*this, NewFD, Kind))
return false;
- return true;
+ Stmt *Body = NewFD->getBody();
+ assert(Body &&
+ "CheckConstexprFunctionDefinition called on function with no body");
+ return CheckConstexprFunctionBody(*this, NewFD, Body, Kind);
}
/// Check the given declaration statement is legal within a constexpr function
@@ -1680,7 +1716,8 @@ bool Sema::CheckConstexprFunctionDecl(co
/// \return true if the body is OK (maybe only as an extension), false if we
/// have diagnosed a problem.
static bool CheckConstexprDeclStmt(Sema &SemaRef, const FunctionDecl *Dcl,
- DeclStmt *DS, SourceLocation &Cxx1yLoc) {
+ DeclStmt *DS, SourceLocation &Cxx1yLoc,
+ Sema::CheckConstexprKind Kind) {
// C++11 [dcl.constexpr]p3 and p4:
// The definition of a constexpr function(p3) or constructor(p4) [...] shall
// contain only
@@ -1704,10 +1741,12 @@ static bool CheckConstexprDeclStmt(Sema
const auto *TN = cast<TypedefNameDecl>(DclIt);
if (TN->getUnderlyingType()->isVariablyModifiedType()) {
// Don't allow variably-modified types in constexpr functions.
- TypeLoc TL = TN->getTypeSourceInfo()->getTypeLoc();
- SemaRef.Diag(TL.getBeginLoc(), diag::err_constexpr_vla)
- << TL.getSourceRange() << TL.getType()
- << isa<CXXConstructorDecl>(Dcl);
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ TypeLoc TL = TN->getTypeSourceInfo()->getTypeLoc();
+ SemaRef.Diag(TL.getBeginLoc(), diag::err_constexpr_vla)
+ << TL.getSourceRange() << TL.getType()
+ << isa<CXXConstructorDecl>(Dcl);
+ }
return false;
}
continue;
@@ -1716,12 +1755,17 @@ static bool CheckConstexprDeclStmt(Sema
case Decl::Enum:
case Decl::CXXRecord:
// C++1y allows types to be defined, not just declared.
- if (cast<TagDecl>(DclIt)->isThisDeclarationADefinition())
- SemaRef.Diag(DS->getBeginLoc(),
- SemaRef.getLangOpts().CPlusPlus14
- ? diag::warn_cxx11_compat_constexpr_type_definition
- : diag::ext_constexpr_type_definition)
- << isa<CXXConstructorDecl>(Dcl);
+ if (cast<TagDecl>(DclIt)->isThisDeclarationADefinition()) {
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ SemaRef.Diag(DS->getBeginLoc(),
+ SemaRef.getLangOpts().CPlusPlus14
+ ? diag::warn_cxx11_compat_constexpr_type_definition
+ : diag::ext_constexpr_type_definition)
+ << isa<CXXConstructorDecl>(Dcl);
+ } else if (!SemaRef.getLangOpts().CPlusPlus14) {
+ return false;
+ }
+ }
continue;
case Decl::EnumConstant:
@@ -1739,31 +1783,37 @@ static bool CheckConstexprDeclStmt(Sema
const auto *VD = cast<VarDecl>(DclIt);
if (VD->isThisDeclarationADefinition()) {
if (VD->isStaticLocal()) {
- SemaRef.Diag(VD->getLocation(),
- diag::err_constexpr_local_var_static)
- << isa<CXXConstructorDecl>(Dcl)
- << (VD->getTLSKind() == VarDecl::TLS_Dynamic);
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ SemaRef.Diag(VD->getLocation(),
+ diag::err_constexpr_local_var_static)
+ << isa<CXXConstructorDecl>(Dcl)
+ << (VD->getTLSKind() == VarDecl::TLS_Dynamic);
+ }
return false;
}
- if (!VD->getType()->isDependentType() &&
- SemaRef.RequireLiteralType(
- VD->getLocation(), VD->getType(),
- diag::err_constexpr_local_var_non_literal_type,
- isa<CXXConstructorDecl>(Dcl)))
+ if (CheckLiteralType(SemaRef, Kind, VD->getLocation(), VD->getType(),
+ diag::err_constexpr_local_var_non_literal_type,
+ isa<CXXConstructorDecl>(Dcl)))
return false;
if (!VD->getType()->isDependentType() &&
!VD->hasInit() && !VD->isCXXForRangeDecl()) {
- SemaRef.Diag(VD->getLocation(),
- diag::err_constexpr_local_var_no_init)
- << isa<CXXConstructorDecl>(Dcl);
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ SemaRef.Diag(VD->getLocation(),
+ diag::err_constexpr_local_var_no_init)
+ << isa<CXXConstructorDecl>(Dcl);
+ }
return false;
}
}
- SemaRef.Diag(VD->getLocation(),
- SemaRef.getLangOpts().CPlusPlus14
- ? diag::warn_cxx11_compat_constexpr_local_var
- : diag::ext_constexpr_local_var)
- << isa<CXXConstructorDecl>(Dcl);
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ SemaRef.Diag(VD->getLocation(),
+ SemaRef.getLangOpts().CPlusPlus14
+ ? diag::warn_cxx11_compat_constexpr_local_var
+ : diag::ext_constexpr_local_var)
+ << isa<CXXConstructorDecl>(Dcl);
+ } else if (!SemaRef.getLangOpts().CPlusPlus14) {
+ return false;
+ }
continue;
}
@@ -1776,8 +1826,10 @@ static bool CheckConstexprDeclStmt(Sema
continue;
default:
- SemaRef.Diag(DS->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
- << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ SemaRef.Diag(DS->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
+ << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
+ }
return false;
}
}
@@ -1792,17 +1844,23 @@ static bool CheckConstexprDeclStmt(Sema
/// struct or union nested within the class being checked.
/// \param Inits All declarations, including anonymous struct/union members and
/// indirect members, for which any initialization was provided.
-/// \param Diagnosed Set to true if an error is produced.
-static void CheckConstexprCtorInitializer(Sema &SemaRef,
+/// \param Diagnosed Whether we've emitted the error message yet. Used to attach
+/// multiple notes for different members to the same error.
+/// \param Kind Whether we're diagnosing a constructor as written or determining
+/// whether the formal requirements are satisfied.
+/// \return \c false if we're checking for validity and the constructor does
+/// not satisfy the requirements on a constexpr constructor.
+static bool CheckConstexprCtorInitializer(Sema &SemaRef,
const FunctionDecl *Dcl,
FieldDecl *Field,
llvm::SmallSet<Decl*, 16> &Inits,
- bool &Diagnosed) {
+ bool &Diagnosed,
+ Sema::CheckConstexprKind Kind) {
if (Field->isInvalidDecl())
- return;
+ return true;
if (Field->isUnnamedBitfield())
- return;
+ return true;
// Anonymous unions with no variant members and empty anonymous structs do not
// need to be explicitly initialized. FIXME: Anonymous structs that contain no
@@ -1811,22 +1869,30 @@ static void CheckConstexprCtorInitialize
(Field->getType()->isUnionType()
? !Field->getType()->getAsCXXRecordDecl()->hasVariantMembers()
: Field->getType()->getAsCXXRecordDecl()->isEmpty()))
- return;
+ return true;
if (!Inits.count(Field)) {
- if (!Diagnosed) {
- SemaRef.Diag(Dcl->getLocation(), diag::err_constexpr_ctor_missing_init);
- Diagnosed = true;
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ if (!Diagnosed) {
+ SemaRef.Diag(Dcl->getLocation(), diag::err_constexpr_ctor_missing_init);
+ Diagnosed = true;
+ }
+ SemaRef.Diag(Field->getLocation(),
+ diag::note_constexpr_ctor_missing_init);
+ } else {
+ return false;
}
- SemaRef.Diag(Field->getLocation(), diag::note_constexpr_ctor_missing_init);
} else if (Field->isAnonymousStructOrUnion()) {
const RecordDecl *RD = Field->getType()->castAs<RecordType>()->getDecl();
for (auto *I : RD->fields())
// If an anonymous union contains an anonymous struct of which any member
// is initialized, all members must be initialized.
if (!RD->isUnion() || Inits.count(I))
- CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed);
+ if (!CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed,
+ Kind))
+ return false;
}
+ return true;
}
/// Check the provided statement is allowed in a constexpr function
@@ -1834,7 +1900,8 @@ static void CheckConstexprCtorInitialize
static bool
CheckConstexprFunctionStmt(Sema &SemaRef, const FunctionDecl *Dcl, Stmt *S,
SmallVectorImpl<SourceLocation> &ReturnStmts,
- SourceLocation &Cxx1yLoc, SourceLocation &Cxx2aLoc) {
+ SourceLocation &Cxx1yLoc, SourceLocation &Cxx2aLoc,
+ Sema::CheckConstexprKind Kind) {
// - its function-body shall be [...] a compound-statement that contains only
switch (S->getStmtClass()) {
case Stmt::NullStmtClass:
@@ -1847,7 +1914,7 @@ CheckConstexprFunctionStmt(Sema &SemaRef
// - using-directives,
// - typedef declarations and alias-declarations that do not define
// classes or enumerations,
- if (!CheckConstexprDeclStmt(SemaRef, Dcl, cast<DeclStmt>(S), Cxx1yLoc))
+ if (!CheckConstexprDeclStmt(SemaRef, Dcl, cast<DeclStmt>(S), Cxx1yLoc, Kind))
return false;
return true;
@@ -1871,7 +1938,7 @@ CheckConstexprFunctionStmt(Sema &SemaRef
CompoundStmt *CompStmt = cast<CompoundStmt>(S);
for (auto *BodyIt : CompStmt->body()) {
if (!CheckConstexprFunctionStmt(SemaRef, Dcl, BodyIt, ReturnStmts,
- Cxx1yLoc, Cxx2aLoc))
+ Cxx1yLoc, Cxx2aLoc, Kind))
return false;
}
return true;
@@ -1889,11 +1956,11 @@ CheckConstexprFunctionStmt(Sema &SemaRef
IfStmt *If = cast<IfStmt>(S);
if (!CheckConstexprFunctionStmt(SemaRef, Dcl, If->getThen(), ReturnStmts,
- Cxx1yLoc, Cxx2aLoc))
+ Cxx1yLoc, Cxx2aLoc, Kind))
return false;
if (If->getElse() &&
!CheckConstexprFunctionStmt(SemaRef, Dcl, If->getElse(), ReturnStmts,
- Cxx1yLoc, Cxx2aLoc))
+ Cxx1yLoc, Cxx2aLoc, Kind))
return false;
return true;
}
@@ -1912,7 +1979,7 @@ CheckConstexprFunctionStmt(Sema &SemaRef
for (Stmt *SubStmt : S->children())
if (SubStmt &&
!CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
- Cxx1yLoc, Cxx2aLoc))
+ Cxx1yLoc, Cxx2aLoc, Kind))
return false;
return true;
@@ -1927,7 +1994,7 @@ CheckConstexprFunctionStmt(Sema &SemaRef
for (Stmt *SubStmt : S->children())
if (SubStmt &&
!CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
- Cxx1yLoc, Cxx2aLoc))
+ Cxx1yLoc, Cxx2aLoc, Kind))
return false;
return true;
@@ -1937,7 +2004,7 @@ CheckConstexprFunctionStmt(Sema &SemaRef
for (Stmt *SubStmt : S->children()) {
if (SubStmt &&
!CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
- Cxx1yLoc, Cxx2aLoc))
+ Cxx1yLoc, Cxx2aLoc, Kind))
return false;
}
return true;
@@ -1947,7 +2014,7 @@ CheckConstexprFunctionStmt(Sema &SemaRef
// try block check).
if (!CheckConstexprFunctionStmt(SemaRef, Dcl,
cast<CXXCatchStmt>(S)->getHandlerBlock(),
- ReturnStmts, Cxx1yLoc, Cxx2aLoc))
+ ReturnStmts, Cxx1yLoc, Cxx2aLoc, Kind))
return false;
return true;
@@ -1961,16 +2028,21 @@ CheckConstexprFunctionStmt(Sema &SemaRef
return true;
}
- SemaRef.Diag(S->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
- << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
+ if (Kind == Sema::CheckConstexprKind::Diagnose) {
+ SemaRef.Diag(S->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
+ << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
+ }
return false;
}
/// Check the body for the given constexpr function declaration only contains
/// the permitted types of statement. C++11 [dcl.constexpr]p3,p4.
///
-/// \return true if the body is OK, false if we have diagnosed a problem.
-bool Sema::CheckConstexprFunctionBody(const FunctionDecl *Dcl, Stmt *Body) {
+/// \return true if the body is OK, false if we have found or diagnosed a
+/// problem.
+static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl,
+ Stmt *Body,
+ Sema::CheckConstexprKind Kind) {
SmallVector<SourceLocation, 4> ReturnStmts;
if (isa<CXXTryStmt>(Body)) {
@@ -1986,11 +2058,20 @@ bool Sema::CheckConstexprFunctionBody(co
//
// This restriction is lifted in C++2a, as long as inner statements also
// apply the general constexpr rules.
- Diag(Body->getBeginLoc(),
- !getLangOpts().CPlusPlus2a
- ? diag::ext_constexpr_function_try_block_cxx2a
- : diag::warn_cxx17_compat_constexpr_function_try_block)
- << isa<CXXConstructorDecl>(Dcl);
+ switch (Kind) {
+ case Sema::CheckConstexprKind::CheckValid:
+ if (!SemaRef.getLangOpts().CPlusPlus2a)
+ return false;
+ break;
+
+ case Sema::CheckConstexprKind::Diagnose:
+ SemaRef.Diag(Body->getBeginLoc(),
+ !SemaRef.getLangOpts().CPlusPlus2a
+ ? diag::ext_constexpr_function_try_block_cxx2a
+ : diag::warn_cxx17_compat_constexpr_function_try_block)
+ << isa<CXXConstructorDecl>(Dcl);
+ break;
+ }
}
// - its function-body shall be [...] a compound-statement that contains only
@@ -2001,23 +2082,30 @@ bool Sema::CheckConstexprFunctionBody(co
SourceLocation Cxx1yLoc, Cxx2aLoc;
for (Stmt *SubStmt : Body->children()) {
if (SubStmt &&
- !CheckConstexprFunctionStmt(*this, Dcl, SubStmt, ReturnStmts,
- Cxx1yLoc, Cxx2aLoc))
+ !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
+ Cxx1yLoc, Cxx2aLoc, Kind))
return false;
}
- if (Cxx2aLoc.isValid())
- Diag(Cxx2aLoc,
- getLangOpts().CPlusPlus2a
+ if (Kind == Sema::CheckConstexprKind::CheckValid) {
+ // If this is only valid as an extension, report that we don't satisfy the
+ // constraints of the current language.
+ if ((Cxx2aLoc.isValid() && !SemaRef.getLangOpts().CPlusPlus2a) ||
+ (Cxx1yLoc.isValid() && !SemaRef.getLangOpts().CPlusPlus17))
+ return false;
+ } else if (Cxx2aLoc.isValid()) {
+ SemaRef.Diag(Cxx2aLoc,
+ SemaRef.getLangOpts().CPlusPlus2a
? diag::warn_cxx17_compat_constexpr_body_invalid_stmt
: diag::ext_constexpr_body_invalid_stmt_cxx2a)
<< isa<CXXConstructorDecl>(Dcl);
- if (Cxx1yLoc.isValid())
- Diag(Cxx1yLoc,
- getLangOpts().CPlusPlus14
+ } else if (Cxx1yLoc.isValid()) {
+ SemaRef.Diag(Cxx1yLoc,
+ SemaRef.getLangOpts().CPlusPlus14
? diag::warn_cxx11_compat_constexpr_body_invalid_stmt
: diag::ext_constexpr_body_invalid_stmt)
<< isa<CXXConstructorDecl>(Dcl);
+ }
if (const CXXConstructorDecl *Constructor
= dyn_cast<CXXConstructorDecl>(Dcl)) {
@@ -2031,7 +2119,9 @@ bool Sema::CheckConstexprFunctionBody(co
if (RD->isUnion()) {
if (Constructor->getNumCtorInitializers() == 0 &&
RD->hasVariantMembers()) {
- Diag(Dcl->getLocation(), diag::err_constexpr_union_ctor_no_init);
+ if (Kind == Sema::CheckConstexprKind::Diagnose)
+ SemaRef.Diag(Dcl->getLocation(),
+ diag::err_constexpr_union_ctor_no_init);
return false;
}
} else if (!Constructor->isDependentContext() &&
@@ -2068,9 +2158,9 @@ bool Sema::CheckConstexprFunctionBody(co
bool Diagnosed = false;
for (auto *I : RD->fields())
- CheckConstexprCtorInitializer(*this, Dcl, I, Inits, Diagnosed);
- if (Diagnosed)
- return false;
+ if (!CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed,
+ Kind))
+ return false;
}
}
} else {
@@ -2079,22 +2169,45 @@ bool Sema::CheckConstexprFunctionBody(co
// statement. We still do, unless the return type might be void, because
// otherwise if there's no return statement, the function cannot
// be used in a core constant expression.
- bool OK = getLangOpts().CPlusPlus14 &&
+ bool OK = SemaRef.getLangOpts().CPlusPlus14 &&
(Dcl->getReturnType()->isVoidType() ||
Dcl->getReturnType()->isDependentType());
- Diag(Dcl->getLocation(),
- OK ? diag::warn_cxx11_compat_constexpr_body_no_return
- : diag::err_constexpr_body_no_return)
- << Dcl->isConsteval();
- if (!OK)
- return false;
+ switch (Kind) {
+ case Sema::CheckConstexprKind::Diagnose:
+ SemaRef.Diag(Dcl->getLocation(),
+ OK ? diag::warn_cxx11_compat_constexpr_body_no_return
+ : diag::err_constexpr_body_no_return)
+ << Dcl->isConsteval();
+ if (!OK)
+ return false;
+ break;
+
+ case Sema::CheckConstexprKind::CheckValid:
+ // The formal requirements don't include this rule in C++14, even
+ // though the "must be able to produce a constant expression" rules
+ // still imply it in some cases.
+ if (!SemaRef.getLangOpts().CPlusPlus14)
+ return false;
+ break;
+ }
} else if (ReturnStmts.size() > 1) {
- Diag(ReturnStmts.back(),
- getLangOpts().CPlusPlus14
- ? diag::warn_cxx11_compat_constexpr_body_multiple_return
- : diag::ext_constexpr_body_multiple_return);
- for (unsigned I = 0; I < ReturnStmts.size() - 1; ++I)
- Diag(ReturnStmts[I], diag::note_constexpr_body_previous_return);
+ switch (Kind) {
+ case Sema::CheckConstexprKind::Diagnose:
+ SemaRef.Diag(
+ ReturnStmts.back(),
+ SemaRef.getLangOpts().CPlusPlus14
+ ? diag::warn_cxx11_compat_constexpr_body_multiple_return
+ : diag::ext_constexpr_body_multiple_return);
+ for (unsigned I = 0; I < ReturnStmts.size() - 1; ++I)
+ SemaRef.Diag(ReturnStmts[I],
+ diag::note_constexpr_body_previous_return);
+ break;
+
+ case Sema::CheckConstexprKind::CheckValid:
+ if (!SemaRef.getLangOpts().CPlusPlus14)
+ return false;
+ break;
+ }
}
}
@@ -2108,12 +2221,17 @@ bool Sema::CheckConstexprFunctionBody(co
// C++11 [dcl.constexpr]p4:
// - every constructor involved in initializing non-static data members and
// base class sub-objects shall be a constexpr constructor.
+ //
+ // Note that this rule is distinct from the "requirements for a constexpr
+ // function", so is not checked in CheckValid mode.
SmallVector<PartialDiagnosticAt, 8> Diags;
- if (!Expr::isPotentialConstantExpr(Dcl, Diags)) {
- Diag(Dcl->getLocation(), diag::ext_constexpr_function_never_constant_expr)
- << isa<CXXConstructorDecl>(Dcl);
+ if (Kind == Sema::CheckConstexprKind::Diagnose &&
+ !Expr::isPotentialConstantExpr(Dcl, Diags)) {
+ SemaRef.Diag(Dcl->getLocation(),
+ diag::ext_constexpr_function_never_constant_expr)
+ << isa<CXXConstructorDecl>(Dcl);
for (size_t I = 0, N = Diags.size(); I != N; ++I)
- Diag(Diags[I].first, Diags[I].second);
+ SemaRef.Diag(Diags[I].first, Diags[I].second);
// Don't return false here: we allow this for compatibility in
// system headers.
}
Modified: cfe/trunk/lib/Sema/SemaLambda.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLambda.cpp?rev=367254&r1=367253&r2=367254&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaLambda.cpp (original)
+++ cfe/trunk/lib/Sema/SemaLambda.cpp Mon Jul 29 12:59:45 2019
@@ -1776,10 +1776,9 @@ ExprResult Sema::BuildLambdaExpr(SourceL
!CallOperator->isConstexpr() &&
!isa<CoroutineBodyStmt>(CallOperator->getBody()) &&
!Class->getDeclContext()->isDependentContext()) {
- TentativeAnalysisScope DiagnosticScopeGuard(*this);
CallOperator->setConstexprKind(
- (CheckConstexprFunctionDecl(CallOperator) &&
- CheckConstexprFunctionBody(CallOperator, CallOperator->getBody()))
+ CheckConstexprFunctionDefinition(CallOperator,
+ CheckConstexprKind::CheckValid)
? CSK_constexpr
: CSK_unspecified);
}
Modified: cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp?rev=367254&r1=367253&r2=367254&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp (original)
+++ cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp Mon Jul 29 12:59:45 2019
@@ -157,11 +157,8 @@ constexpr int DisallowedStmtsCXX1Y_2_1()
constexpr int DisallowedStmtsCXX1Y_3() {
// - a try-block,
try {} catch (...) {}
-#ifndef CXX2A
+#if !defined(CXX2A)
// expected-error at -2 {{use of this statement in a constexpr function is a C++2a extension}}
-#ifndef CXX1Y
- // expected-error at -4 {{use of this statement in a constexpr function is a C++14 extension}}
-#endif
#endif
return 0;
}
Modified: cfe/trunk/test/SemaCXX/cxx1z-constexpr-lambdas.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1z-constexpr-lambdas.cpp?rev=367254&r1=367253&r2=367254&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/cxx1z-constexpr-lambdas.cpp (original)
+++ cfe/trunk/test/SemaCXX/cxx1z-constexpr-lambdas.cpp Mon Jul 29 12:59:45 2019
@@ -1,4 +1,5 @@
// RUN: %clang_cc1 -std=c++1z -verify -fsyntax-only -fblocks %s -fcxx-exceptions
+// RUN: %clang_cc1 -std=c++2a -verify -fsyntax-only -fblocks %s -fcxx-exceptions
// RUN: %clang_cc1 -std=c++1z -verify -fsyntax-only -fblocks -fdelayed-template-parsing %s -fcxx-exceptions
// RUN: %clang_cc1 -std=c++14 -verify -fsyntax-only -fblocks %s -DCPP14_AND_EARLIER -fcxx-exceptions
@@ -25,6 +26,34 @@ namespace ns2 {
auto L = [](int I) constexpr { asm("non-constexpr"); }; //expected-error{{not allowed in constexpr function}}
} // end ns1
+// This is not constexpr until C++20, as the requirements on constexpr
+// functions don't permit try-catch blocks.
+#if __cplusplus <= 201703L
+// expected-error@#try-catch {{constant expression}}
+// expected-note@#try-catch {{non-constexpr function 'operator()'}}
+// expected-note@#try-catch {{declared here}}
+#endif
+constexpr int try_catch = [] { // #try-catch
+ try { return 0; } catch (...) { return 1; }
+}();
+
+// These lambdas have constexpr operator() even though they can never produce a
+// constant expression.
+auto never_constant_1 = [] { // expected-note {{here}}
+ volatile int n = 0;
+ return n;
+};
+auto never_constant_2 = [] () -> int { // expected-note {{here}}
+};
+struct test_never_constant {
+ #if __cplusplus >= 201703L
+ // expected-error at +3 {{non-constexpr declaration of 'operator()' follows constexpr declaration}}
+ // expected-error at +3 {{non-constexpr declaration of 'operator()' follows constexpr declaration}}
+ #endif
+ friend auto decltype(never_constant_1)::operator()() const;
+ friend int decltype(never_constant_2)::operator()() const;
+};
+
} // end ns test_constexpr_checking
namespace test_constexpr_call {
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