r180022 - C++1y constexpr extensions, round 1: Allow most forms of declaration and
Richard Smith
richard-llvm at metafoo.co.uk
Mon Apr 22 08:31:51 PDT 2013
Author: rsmith
Date: Mon Apr 22 10:31:51 2013
New Revision: 180022
URL: http://llvm.org/viewvc/llvm-project?rev=180022&view=rev
Log:
C++1y constexpr extensions, round 1: Allow most forms of declaration and
statement in constexpr functions. Everything which doesn't require variable
mutation is also allowed as an extension in C++11. 'void' becomes a literal
type to support constexpr functions which return 'void'.
Added:
cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp
Modified:
cfe/trunk/include/clang/AST/Type.h
cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/AST/DeclCXX.cpp
cfe/trunk/lib/AST/Expr.cpp
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/lib/AST/Type.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/lib/Sema/SemaDeclCXX.cpp
cfe/trunk/lib/Sema/SemaExprCXX.cpp
cfe/trunk/lib/Sema/SemaType.cpp
cfe/trunk/test/CXX/basic/basic.types/p10.cpp
cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp
cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp
cfe/trunk/test/CXX/except/except.spec/p1.cpp
cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
Modified: cfe/trunk/include/clang/AST/Type.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Type.h?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Type.h (original)
+++ cfe/trunk/include/clang/AST/Type.h Mon Apr 22 10:31:51 2013
@@ -1443,8 +1443,8 @@ public:
}
/// isLiteralType - Return true if this is a literal type
- /// (C++0x [basic.types]p10)
- bool isLiteralType() const;
+ /// (C++11 [basic.types]p10)
+ bool isLiteralType(ASTContext &Ctx) const;
/// \brief Test if this type is a standard-layout type.
/// (C++0x [basic.type]p9)
Modified: cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td Mon Apr 22 10:31:51 2013
@@ -26,6 +26,8 @@ def note_constexpr_lshift_discards : Not
def note_constexpr_invalid_function : Note<
"%select{non-constexpr|undefined}0 %select{function|constructor}1 %2 cannot "
"be used in a constant expression">;
+def note_constexpr_no_return : Note<
+ "control reached end of constexpr function">;
def note_constexpr_virtual_call : Note<
"cannot evaluate virtual function call in a constant expression">;
def note_constexpr_virtual_base : Note<
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Apr 22 10:31:51 2013
@@ -1593,20 +1593,54 @@ def err_constexpr_non_literal_param : Er
"not a literal type">;
def err_constexpr_body_invalid_stmt : Error<
"statement not allowed in constexpr %select{function|constructor}0">;
-def err_constexpr_type_definition : Error<
- "types cannot be defined in a constexpr %select{function|constructor}0">;
+def ext_constexpr_body_invalid_stmt : ExtWarn<
+ "use of this statement in a constexpr %select{function|constructor}0 "
+ "is a C++1y extension">, InGroup<CXX1y>;
+def warn_cxx11_compat_constexpr_body_invalid_stmt : Warning<
+ "use of this statement in a constexpr %select{function|constructor}0 "
+ "is incompatible with C++ standards before C++1y">,
+ InGroup<CXXPre1yCompat>, DefaultIgnore;
+def ext_constexpr_type_definition : ExtWarn<
+ "type definition in a constexpr %select{function|constructor}0 "
+ "is a C++1y extension">, InGroup<CXX1y>;
+def warn_cxx11_compat_constexpr_type_definition : Warning<
+ "type definition in a constexpr %select{function|constructor}0 "
+ "is incompatible with C++ standards before C++1y">,
+ InGroup<CXXPre1yCompat>, DefaultIgnore;
def err_constexpr_vla : Error<
"variably-modified type %0 cannot be used in a constexpr "
"%select{function|constructor}1">;
-def err_constexpr_var_declaration : Error<
- "variables cannot be declared in a constexpr %select{function|constructor}0">;
+def ext_constexpr_local_var : ExtWarn<
+ "variable declaration in a constexpr %select{function|constructor}0 "
+ "is a C++1y extension">, InGroup<CXX1y>;
+def warn_cxx11_compat_constexpr_local_var : Warning<
+ "variable declaration in a constexpr %select{function|constructor}0 "
+ "is incompatible with C++ standards before C++1y">,
+ InGroup<CXXPre1yCompat>, DefaultIgnore;
+def err_constexpr_local_var_static : Error<
+ "%select{static|thread_local}1 variable not permitted in a constexpr "
+ "%select{function|constructor}0">;
+def err_constexpr_local_var_non_literal_type : Error<
+ "variable of non-literal type %1 cannot be defined in a constexpr "
+ "%select{function|constructor}0">;
+def err_constexpr_local_var_no_init : Error<
+ "variables defined in a constexpr %select{function|constructor}0 must be "
+ "initialized">;
def ext_constexpr_function_never_constant_expr : ExtWarn<
"constexpr %select{function|constructor}0 never produces a "
"constant expression">, InGroup<DiagGroup<"invalid-constexpr">>, DefaultError;
def err_constexpr_body_no_return : Error<
"no return statement in constexpr function">;
-def err_constexpr_body_multiple_return : Error<
- "multiple return statements in constexpr function">;
+def warn_cxx11_compat_constexpr_body_no_return : Warning<
+ "constexpr function with no return statements is incompatible with C++ "
+ "standards before C++1y">, InGroup<CXXPre1yCompat>, DefaultIgnore;
+def ext_constexpr_body_multiple_return : ExtWarn<
+ "multiple return statements in constexpr function is a C++1y extension">,
+ InGroup<CXX1y>;
+def warn_cxx11_compat_constexpr_body_multiple_return : Warning<
+ "multiple return statements in constexpr function "
+ "is incompatible with C++ standards before C++1y">,
+ InGroup<CXXPre1yCompat>, DefaultIgnore;
def note_constexpr_body_previous_return : Note<
"previous return statement is here">;
def err_constexpr_function_try_block : Error<
Modified: cfe/trunk/lib/AST/DeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclCXX.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/AST/DeclCXX.cpp (original)
+++ cfe/trunk/lib/AST/DeclCXX.cpp Mon Apr 22 10:31:51 2013
@@ -186,7 +186,7 @@ CXXRecordDecl::setBases(CXXBaseSpecifier
data().IsStandardLayout = false;
// Record if this base is the first non-literal field or base.
- if (!hasNonLiteralTypeFieldsOrBases() && !BaseType->isLiteralType())
+ if (!hasNonLiteralTypeFieldsOrBases() && !BaseType->isLiteralType(C))
data().HasNonLiteralTypeFieldsOrBases = true;
// Now go through all virtual bases of this base and add them.
@@ -676,7 +676,7 @@ void CXXRecordDecl::addedMember(Decl *D)
}
// Record if this field is the first non-literal or volatile field or base.
- if (!T->isLiteralType() || T.isVolatileQualified())
+ if (!T->isLiteralType(Context) || T.isVolatileQualified())
data().HasNonLiteralTypeFieldsOrBases = true;
if (Field->hasInClassInitializer()) {
@@ -845,7 +845,7 @@ void CXXRecordDecl::addedMember(Decl *D)
}
} else {
// Base element type of field is a non-class type.
- if (!T->isLiteralType() ||
+ if (!T->isLiteralType(Context) ||
(!Field->hasInClassInitializer() && !isUnion()))
data().DefaultedDefaultConstructorIsConstexpr = false;
Modified: cfe/trunk/lib/AST/Expr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Expr.cpp (original)
+++ cfe/trunk/lib/AST/Expr.cpp Mon Apr 22 10:31:51 2013
@@ -289,7 +289,7 @@ static void computeDeclRefDependence(AST
// expression that is value-dependent [C++11]
if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
if ((Ctx.getLangOpts().CPlusPlus11 ?
- Var->getType()->isLiteralType() :
+ Var->getType()->isLiteralType(Ctx) :
Var->getType()->isIntegralOrEnumerationType()) &&
(Var->getType().isConstQualified() ||
Var->getType()->isReferenceType())) {
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Mon Apr 22 10:31:51 2013
@@ -290,7 +290,7 @@ namespace {
// Note that we intentionally use std::map here so that references to
// values are stable.
- typedef std::map<const Expr*, APValue> MapTy;
+ typedef std::map<const void*, APValue> MapTy;
typedef MapTy::const_iterator temp_iterator;
/// Temporaries - Temporary lvalues materialized within this stack frame.
MapTy Temporaries;
@@ -913,6 +913,14 @@ static bool EvaluateComplex(const Expr *
// Misc utilities
//===----------------------------------------------------------------------===//
+/// Evaluate an expression to see if it had side-effects, and discard its
+/// result.
+static void EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
+ APValue Scratch;
+ if (!Evaluate(Scratch, Info, E))
+ Info.EvalStatus.HasSideEffects = true;
+}
+
/// Should this call expression be treated as a string literal?
static bool IsStringLiteralCall(const CallExpr *E) {
unsigned Builtin = E->isBuiltinCall();
@@ -1046,7 +1054,7 @@ static bool CheckLValueConstantExpressio
/// Check that this core constant expression is of literal type, and if not,
/// produce an appropriate diagnostic.
static bool CheckLiteralType(EvalInfo &Info, const Expr *E) {
- if (!E->isRValue() || E->getType()->isLiteralType())
+ if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx))
return true;
// Prvalue constant expressions must be of literal types.
@@ -1461,6 +1469,15 @@ static bool EvaluateVarDeclInit(EvalInfo
return true;
}
+ // If this is a local variable, dig out its value.
+ if (VD->hasLocalStorage() && Frame && Frame->Index > 1) {
+ Result = Frame->Temporaries[VD];
+ // If we've carried on past an unevaluatable local variable initializer,
+ // we can't go any further. This can happen during potential constant
+ // expression checking.
+ return !Result.isUninit();
+ }
+
// Dig out the initializer, and use the declaration which it's attached to.
const Expr *Init = VD->getAnyInitializer(VD);
if (!Init || Init->isValueDependent()) {
@@ -1803,7 +1820,9 @@ static bool HandleLValueToRValueConversi
return false;
}
- if (!isa<ParmVarDecl>(VD)) {
+ // Unless we're looking at a local variable or argument in a constexpr call,
+ // the variable we're reading must be const.
+ if (LVal.CallIndex <= 1 || !VD->hasLocalStorage()) {
if (VD->isConstexpr()) {
// OK, we can read this variable.
} else if (VT->isIntegralOrEnumerationType()) {
@@ -1911,7 +1930,7 @@ static bool EvaluateObjectArgument(EvalI
if (Object->isGLValue())
return EvaluateLValue(Object, This, Info);
- if (Object->getType()->isLiteralType())
+ if (Object->getType()->isLiteralType(Info.Ctx))
return EvaluateTemporary(Object, This, Info);
return false;
@@ -2060,20 +2079,61 @@ enum EvalStmtResult {
};
}
+static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
+ if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
+ // We don't need to evaluate the initializer for a static local.
+ if (!VD->hasLocalStorage())
+ return true;
+
+ LValue Result;
+ Result.set(VD, Info.CurrentCall->Index);
+ APValue &Val = Info.CurrentCall->Temporaries[VD];
+
+ if (!EvaluateInPlace(Val, Info, Result, VD->getInit())) {
+ // Wipe out any partially-computed value, to allow tracking that this
+ // evaluation failed.
+ Val = APValue();
+ return false;
+ }
+ }
+
+ return true;
+}
+
// Evaluate a statement.
static EvalStmtResult EvaluateStmt(APValue &Result, EvalInfo &Info,
const Stmt *S) {
+ // FIXME: Mark all temporaries in the current frame as destroyed at
+ // the end of each full-expression.
switch (S->getStmtClass()) {
default:
+ if (const Expr *E = dyn_cast<Expr>(S)) {
+ EvaluateIgnoredValue(Info, E);
+ // Don't bother evaluating beyond an expression-statement which couldn't
+ // be evaluated.
+ if (Info.EvalStatus.HasSideEffects && !Info.keepEvaluatingAfterFailure())
+ return ESR_Failed;
+ return ESR_Succeeded;
+ }
+
+ Info.Diag(S->getLocStart());
return ESR_Failed;
case Stmt::NullStmtClass:
- case Stmt::DeclStmtClass:
return ESR_Succeeded;
+ case Stmt::DeclStmtClass: {
+ const DeclStmt *DS = cast<DeclStmt>(S);
+ for (DeclStmt::const_decl_iterator DclIt = DS->decl_begin(),
+ DclEnd = DS->decl_end(); DclIt != DclEnd; ++DclIt)
+ if (!EvaluateDecl(Info, *DclIt) && !Info.keepEvaluatingAfterFailure())
+ return ESR_Failed;
+ return ESR_Succeeded;
+ }
+
case Stmt::ReturnStmtClass: {
const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
- if (!Evaluate(Result, Info, RetExpr))
+ if (RetExpr && !Evaluate(Result, Info, RetExpr))
return ESR_Failed;
return ESR_Returned;
}
@@ -2088,6 +2148,28 @@ static EvalStmtResult EvaluateStmt(APVal
}
return ESR_Succeeded;
}
+
+ case Stmt::IfStmtClass: {
+ const IfStmt *IS = cast<IfStmt>(S);
+
+ // Evaluate the condition, as either a var decl or as an expression.
+ bool Cond;
+ if (VarDecl *CondDecl = IS->getConditionVariable()) {
+ if (!EvaluateDecl(Info, CondDecl))
+ return ESR_Failed;
+ if (!HandleConversionToBool(Info.CurrentCall->Temporaries[CondDecl],
+ Cond))
+ return ESR_Failed;
+ } else if (!EvaluateAsBooleanCondition(IS->getCond(), Cond, Info))
+ return ESR_Failed;
+
+ if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
+ EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
+ if (ESR != ESR_Succeeded)
+ return ESR;
+ }
+ return ESR_Succeeded;
+ }
}
}
@@ -2181,7 +2263,10 @@ static bool HandleFunctionCall(SourceLoc
return false;
CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data());
- return EvaluateStmt(Result, Info, Body) == ESR_Returned;
+ EvalStmtResult ESR = EvaluateStmt(Result, Info, Body);
+ if (ESR == ESR_Succeeded)
+ Info.Diag(Callee->getLocEnd(), diag::note_constexpr_no_return);
+ return ESR == ESR_Returned;
}
/// Evaluate a constructor call.
@@ -2207,7 +2292,9 @@ static bool HandleConstructorCall(Source
// If it's a delegating constructor, just delegate.
if (Definition->isDelegatingConstructor()) {
CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
- return EvaluateInPlace(Result, Info, This, (*I)->getInit());
+ if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()))
+ return false;
+ return EvaluateStmt(Result, Info, Definition->getBody()) != ESR_Failed;
}
// For a trivial copy or move constructor, perform an APValue copy. This is
@@ -2307,7 +2394,8 @@ static bool HandleConstructorCall(Source
}
}
- return Success;
+ return Success &&
+ EvaluateStmt(Result, Info, Definition->getBody()) != ESR_Failed;
}
//===----------------------------------------------------------------------===//
@@ -2660,9 +2748,7 @@ public:
/// Visit a value which is evaluated, but whose value is ignored.
void VisitIgnoredValue(const Expr *E) {
- APValue Scratch;
- if (!Evaluate(Scratch, Info, E))
- Info.EvalStatus.HasSideEffects = true;
+ EvaluateIgnoredValue(Info, E);
}
};
@@ -2868,7 +2954,7 @@ bool LValueExprEvaluator::VisitDeclRefEx
bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
if (!VD->getType()->isReferenceType()) {
- if (isa<ParmVarDecl>(VD)) {
+ if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) {
Result.set(VD, Info.CurrentCall->Index);
return true;
}
Modified: cfe/trunk/lib/AST/Type.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Type.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Type.cpp (original)
+++ cfe/trunk/lib/AST/Type.cpp Mon Apr 22 10:31:51 2013
@@ -1142,16 +1142,20 @@ bool QualType::isTriviallyCopyableType(A
-bool Type::isLiteralType() const {
+bool Type::isLiteralType(ASTContext &Ctx) const {
if (isDependentType())
return false;
- // C++0x [basic.types]p10:
+ // C++1y [basic.types]p10:
+ // A type is a literal type if it is:
+ // -- cv void; or
+ if (Ctx.getLangOpts().CPlusPlus1y && isVoidType())
+ return true;
+
+ // C++11 [basic.types]p10:
// A type is a literal type if it is:
// [...]
- // -- an array of literal type.
- // Extension: variable arrays cannot be literal types, since they're
- // runtime-sized.
+ // -- an array of literal type other than an array of runtime bound; or
if (isVariableArrayType())
return false;
const Type *BaseTy = getBaseElementTypeUnsafe();
@@ -1162,7 +1166,7 @@ bool Type::isLiteralType() const {
if (BaseTy->isIncompleteType())
return false;
- // C++0x [basic.types]p10:
+ // C++11 [basic.types]p10:
// A type is a literal type if it is:
// -- a scalar type; or
// As an extension, Clang treats vector types and complex types as
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Mon Apr 22 10:31:51 2013
@@ -7626,7 +7626,7 @@ void Sema::AddInitializerToDecl(Decl *Re
}
// Suggest adding 'constexpr' in C++11 for literal types.
- } else if (getLangOpts().CPlusPlus11 && DclT->isLiteralType()) {
+ } else if (getLangOpts().CPlusPlus11 && DclT->isLiteralType(Context)) {
Diag(VDecl->getLocation(), diag::err_in_class_initializer_literal_type)
<< DclT << Init->getSourceRange()
<< FixItHint::CreateInsertion(VDecl->getLocStart(), "constexpr ");
Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Mon Apr 22 10:31:51 2013
@@ -775,12 +775,13 @@ bool Sema::CheckConstexprFunctionDecl(co
}
/// Check the given declaration statement is legal within a constexpr function
-/// body. C++0x [dcl.constexpr]p3,p4.
+/// body. C++11 [dcl.constexpr]p3,p4, and C++1y [dcl.constexpr]p3.
///
-/// \return true if the body is OK, false if we have diagnosed a problem.
+/// \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) {
- // C++0x [dcl.constexpr]p3 and p4:
+ DeclStmt *DS, SourceLocation &Cxx1yLoc) {
+ // C++11 [dcl.constexpr]p3 and p4:
// The definition of a constexpr function(p3) or constructor(p4) [...] shall
// contain only
for (DeclStmt::decl_iterator DclIt = DS->decl_begin(),
@@ -791,6 +792,7 @@ static bool CheckConstexprDeclStmt(Sema
case Decl::UsingShadow:
case Decl::UsingDirective:
case Decl::UnresolvedUsingTypename:
+ case Decl::UnresolvedUsingValue:
// - static_assert-declarations
// - using-declarations,
// - using-directives,
@@ -814,20 +816,62 @@ static bool CheckConstexprDeclStmt(Sema
case Decl::Enum:
case Decl::CXXRecord:
- // As an extension, we allow the declaration (but not the definition) of
- // classes and enumerations in all declarations, not just in typedef and
- // alias declarations.
- if (cast<TagDecl>(*DclIt)->isThisDeclarationADefinition()) {
- SemaRef.Diag(DS->getLocStart(), diag::err_constexpr_type_definition)
+ // C++1y allows types to be defined, not just declared.
+ if (cast<TagDecl>(*DclIt)->isThisDeclarationADefinition())
+ SemaRef.Diag(DS->getLocStart(),
+ SemaRef.getLangOpts().CPlusPlus1y
+ ? diag::warn_cxx11_compat_constexpr_type_definition
+ : diag::ext_constexpr_type_definition)
<< isa<CXXConstructorDecl>(Dcl);
- return false;
- }
continue;
- case Decl::Var:
- SemaRef.Diag(DS->getLocStart(), diag::err_constexpr_var_declaration)
+ case Decl::EnumConstant:
+ case Decl::IndirectField:
+ case Decl::ParmVar:
+ // These can only appear with other declarations which are banned in
+ // C++11 and permitted in C++1y, so ignore them.
+ continue;
+
+ case Decl::Var: {
+ // C++1y [dcl.constexpr]p3 allows anything except:
+ // a definition of a variable of non-literal type or of static or
+ // thread storage duration or for which no initialization is performed.
+ VarDecl *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);
+ return false;
+ }
+ if (SemaRef.RequireLiteralType(
+ VD->getLocation(), VD->getType(),
+ diag::err_constexpr_local_var_non_literal_type,
+ isa<CXXConstructorDecl>(Dcl)))
+ return false;
+ if (!VD->hasInit()) {
+ SemaRef.Diag(VD->getLocation(),
+ diag::err_constexpr_local_var_no_init)
+ << isa<CXXConstructorDecl>(Dcl);
+ return false;
+ }
+ }
+ SemaRef.Diag(VD->getLocation(),
+ SemaRef.getLangOpts().CPlusPlus1y
+ ? diag::warn_cxx11_compat_constexpr_local_var
+ : diag::ext_constexpr_local_var)
<< isa<CXXConstructorDecl>(Dcl);
- return false;
+ continue;
+ }
+
+ case Decl::NamespaceAlias:
+ case Decl::Function:
+ // These are disallowed in C++11 and permitted in C++1y. Allow them
+ // everywhere as an extension.
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = DS->getLocStart();
+ continue;
default:
SemaRef.Diag(DS->getLocStart(), diag::err_constexpr_body_invalid_stmt)
@@ -876,6 +920,124 @@ static void CheckConstexprCtorInitialize
}
}
+/// Check the provided statement is allowed in a constexpr function
+/// definition.
+static bool
+CheckConstexprFunctionStmt(Sema &SemaRef, const FunctionDecl *Dcl, Stmt *S,
+ llvm::SmallVectorImpl<SourceLocation> &ReturnStmts,
+ SourceLocation &Cxx1yLoc) {
+ // - its function-body shall be [...] a compound-statement that contains only
+ switch (S->getStmtClass()) {
+ case Stmt::NullStmtClass:
+ // - null statements,
+ return true;
+
+ case Stmt::DeclStmtClass:
+ // - static_assert-declarations
+ // - using-declarations,
+ // - using-directives,
+ // - typedef declarations and alias-declarations that do not define
+ // classes or enumerations,
+ if (!CheckConstexprDeclStmt(SemaRef, Dcl, cast<DeclStmt>(S), Cxx1yLoc))
+ return false;
+ return true;
+
+ case Stmt::ReturnStmtClass:
+ // - and exactly one return statement;
+ if (isa<CXXConstructorDecl>(Dcl)) {
+ // C++1y allows return statements in constexpr constructors.
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = S->getLocStart();
+ return true;
+ }
+
+ ReturnStmts.push_back(S->getLocStart());
+ return true;
+
+ case Stmt::CompoundStmtClass: {
+ // C++1y allows compound-statements.
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = S->getLocStart();
+
+ CompoundStmt *CompStmt = cast<CompoundStmt>(S);
+ for (CompoundStmt::body_iterator BodyIt = CompStmt->body_begin(),
+ BodyEnd = CompStmt->body_end(); BodyIt != BodyEnd; ++BodyIt) {
+ if (!CheckConstexprFunctionStmt(SemaRef, Dcl, *BodyIt, ReturnStmts,
+ Cxx1yLoc))
+ return false;
+ }
+ return true;
+ }
+
+ case Stmt::AttributedStmtClass:
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = S->getLocStart();
+ return true;
+
+ case Stmt::IfStmtClass: {
+ // C++1y allows if-statements.
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = S->getLocStart();
+
+ IfStmt *If = cast<IfStmt>(S);
+ if (!CheckConstexprFunctionStmt(SemaRef, Dcl, If->getThen(), ReturnStmts,
+ Cxx1yLoc))
+ return false;
+ if (If->getElse() &&
+ !CheckConstexprFunctionStmt(SemaRef, Dcl, If->getElse(), ReturnStmts,
+ Cxx1yLoc))
+ return false;
+ return true;
+ }
+
+ case Stmt::WhileStmtClass:
+ case Stmt::DoStmtClass:
+ case Stmt::ForStmtClass:
+ case Stmt::CXXForRangeStmtClass:
+ case Stmt::ContinueStmtClass:
+ // C++1y allows all of these. We don't allow them as extensions in C++11,
+ // because they don't make sense without variable mutation.
+ if (!SemaRef.getLangOpts().CPlusPlus1y)
+ break;
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = S->getLocStart();
+ for (Stmt::child_range Children = S->children(); Children; ++Children)
+ if (*Children &&
+ !CheckConstexprFunctionStmt(SemaRef, Dcl, *Children, ReturnStmts,
+ Cxx1yLoc))
+ return false;
+ return true;
+
+ case Stmt::SwitchStmtClass:
+ case Stmt::CaseStmtClass:
+ case Stmt::DefaultStmtClass:
+ case Stmt::BreakStmtClass:
+ // C++1y allows switch-statements, and since they don't need variable
+ // mutation, we can reasonably allow them in C++11 as an extension.
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = S->getLocStart();
+ for (Stmt::child_range Children = S->children(); Children; ++Children)
+ if (*Children &&
+ !CheckConstexprFunctionStmt(SemaRef, Dcl, *Children, ReturnStmts,
+ Cxx1yLoc))
+ return false;
+ return true;
+
+ default:
+ if (!isa<Expr>(S))
+ break;
+
+ // C++1y allows expression-statements.
+ if (!Cxx1yLoc.isValid())
+ Cxx1yLoc = S->getLocStart();
+ return true;
+ }
+
+ SemaRef.Diag(S->getLocStart(), diag::err_constexpr_body_invalid_stmt)
+ << isa<CXXConstructorDecl>(Dcl);
+ return false;
+}
+
/// Check the body for the given constexpr function declaration only contains
/// the permitted types of statement. C++11 [dcl.constexpr]p3,p4.
///
@@ -896,43 +1058,24 @@ bool Sema::CheckConstexprFunctionBody(co
return false;
}
+ SmallVector<SourceLocation, 4> ReturnStmts;
+
// - its function-body shall be [...] a compound-statement that contains only
+ // [... list of cases ...]
CompoundStmt *CompBody = cast<CompoundStmt>(Body);
-
- SmallVector<SourceLocation, 4> ReturnStmts;
+ SourceLocation Cxx1yLoc;
for (CompoundStmt::body_iterator BodyIt = CompBody->body_begin(),
BodyEnd = CompBody->body_end(); BodyIt != BodyEnd; ++BodyIt) {
- switch ((*BodyIt)->getStmtClass()) {
- case Stmt::NullStmtClass:
- // - null statements,
- continue;
-
- case Stmt::DeclStmtClass:
- // - static_assert-declarations
- // - using-declarations,
- // - using-directives,
- // - typedef declarations and alias-declarations that do not define
- // classes or enumerations,
- if (!CheckConstexprDeclStmt(*this, Dcl, cast<DeclStmt>(*BodyIt)))
- return false;
- continue;
-
- case Stmt::ReturnStmtClass:
- // - and exactly one return statement;
- if (isa<CXXConstructorDecl>(Dcl))
- break;
-
- ReturnStmts.push_back((*BodyIt)->getLocStart());
- continue;
-
- default:
- break;
- }
+ if (!CheckConstexprFunctionStmt(*this, Dcl, *BodyIt, ReturnStmts, Cxx1yLoc))
+ return false;
+ }
- Diag((*BodyIt)->getLocStart(), diag::err_constexpr_body_invalid_stmt)
+ if (Cxx1yLoc.isValid())
+ Diag(Cxx1yLoc,
+ getLangOpts().CPlusPlus1y
+ ? diag::warn_cxx11_compat_constexpr_body_invalid_stmt
+ : diag::ext_constexpr_body_invalid_stmt)
<< isa<CXXConstructorDecl>(Dcl);
- return false;
- }
if (const CXXConstructorDecl *Constructor
= dyn_cast<CXXConstructorDecl>(Dcl)) {
@@ -988,14 +1131,23 @@ bool Sema::CheckConstexprFunctionBody(co
}
} else {
if (ReturnStmts.empty()) {
- Diag(Dcl->getLocation(), diag::err_constexpr_body_no_return);
+ // C++1y doesn't require constexpr functions to contain a 'return'
+ // statement. We still do, unless the return type is void, because
+ // otherwise if there's no return statement, the function cannot
+ // be used in a core constant expression.
+ Diag(Dcl->getLocation(),
+ getLangOpts().CPlusPlus1y && Dcl->getResultType()->isVoidType()
+ ? diag::warn_cxx11_compat_constexpr_body_no_return
+ : diag::err_constexpr_body_no_return);
return false;
}
if (ReturnStmts.size() > 1) {
- Diag(ReturnStmts.back(), diag::err_constexpr_body_multiple_return);
+ Diag(ReturnStmts.back(),
+ getLangOpts().CPlusPlus1y
+ ? 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);
- return false;
}
}
Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Mon Apr 22 10:31:51 2013
@@ -3137,7 +3137,7 @@ static bool EvaluateUnaryTypeTrait(Sema
case UTT_IsPOD:
return T.isPODType(Self.Context);
case UTT_IsLiteral:
- return T->isLiteralType();
+ return T->isLiteralType(Self.Context);
case UTT_IsEmpty:
if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
return !RD->isUnion() && RD->isEmpty();
Modified: cfe/trunk/lib/Sema/SemaType.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaType.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaType.cpp (original)
+++ cfe/trunk/lib/Sema/SemaType.cpp Mon Apr 22 10:31:51 2013
@@ -4809,7 +4809,7 @@ bool Sema::RequireLiteralType(SourceLoca
QualType ElemType = Context.getBaseElementType(T);
RequireCompleteType(Loc, ElemType, 0);
- if (T->isLiteralType())
+ if (T->isLiteralType(Context))
return false;
if (Diagnoser.Suppressed)
@@ -4851,7 +4851,7 @@ bool Sema::RequireLiteralType(SourceLoca
} else if (RD->hasNonLiteralTypeFieldsOrBases()) {
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
- if (!I->getType()->isLiteralType()) {
+ if (!I->getType()->isLiteralType(Context)) {
Diag(I->getLocStart(),
diag::note_non_literal_base_class)
<< RD << I->getType() << I->getSourceRange();
@@ -4860,7 +4860,7 @@ bool Sema::RequireLiteralType(SourceLoca
}
for (CXXRecordDecl::field_iterator I = RD->field_begin(),
E = RD->field_end(); I != E; ++I) {
- if (!I->getType()->isLiteralType() ||
+ if (!I->getType()->isLiteralType(Context) ||
I->getType().isVolatileQualified()) {
Diag(I->getLocation(), diag::note_non_literal_field)
<< RD << *I << I->getType()
Modified: cfe/trunk/test/CXX/basic/basic.types/p10.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/basic/basic.types/p10.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/test/CXX/basic/basic.types/p10.cpp (original)
+++ cfe/trunk/test/CXX/basic/basic.types/p10.cpp Mon Apr 22 10:31:51 2013
@@ -1,9 +1,16 @@
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++1y %s -DCXX1Y
struct NonLiteral { NonLiteral(); };
// A type is a literal type if it is:
+// [C++1y] - void
+constexpr void f() {}
+#ifndef CXX1Y
+// expected-error at -2 {{'void' is not a literal type}}
+#endif
+
// - a scalar type
constexpr int f1(double) { return 0; }
@@ -11,7 +18,6 @@ constexpr int f1(double) { return 0; }
struct S { S(); };
constexpr int f2(S &) { return 0; }
-// FIXME: I'm not entirely sure whether the following is legal or not...
struct BeingDefined;
extern BeingDefined beingdefined;
struct BeingDefined {
@@ -117,7 +123,7 @@ struct MemberType {
constexpr int f(MemberType<int>) { return 0; }
constexpr int f(MemberType<NonLiteral>) { return 0; } // expected-error {{not a literal type}}
-// - an array of literal type
+// - an array of literal type [C++1y] other than an array of runtime bound
struct ArrGood {
Agg agg[24];
double d[12];
@@ -130,3 +136,7 @@ struct ArrBad {
S s[3]; // expected-note {{data member 's' of non-literal type 'S [3]'}}
};
constexpr int f(ArrBad) { return 0; } // expected-error {{1st parameter type 'ArrBad' is not a literal type}}
+
+constexpr int arb(int n) {
+ int a[n]; // expected-error {{variable of non-literal type 'int [n]' cannot be defined in a constexpr function}}
+}
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=180022&r1=180021&r2=180022&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 Apr 22 10:31:51 2013
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -verify -std=c++11 %s
+// RUN: %clang_cc1 -verify -fcxx-exceptions -triple=x86_64-linux-gnu -std=c++11 -Werror=c++1y-extensions %s
+// RUN: %clang_cc1 -verify -fcxx-exceptions -triple=x86_64-linux-gnu -std=c++1y -DCXX1Y %s
namespace N {
typedef char C;
@@ -8,7 +9,7 @@ namespace M {
typedef double D;
}
-struct NonLiteral { // expected-note 2{{no constexpr constructors}}
+struct NonLiteral { // expected-note 3{{no constexpr constructors}}
NonLiteral() {}
NonLiteral(int) {}
};
@@ -37,7 +38,10 @@ struct T : SS, NonLiteral { // expected-
// - its return type shall be a literal type;
constexpr NonLiteral NonLiteralReturn() const { return {}; } // expected-error {{constexpr function's return type 'NonLiteral' is not a literal type}}
- constexpr void VoidReturn() const { return; } // expected-error {{constexpr function's return type 'void' is not a literal type}}
+ constexpr void VoidReturn() const { return; }
+#ifndef CXX1Y
+ // expected-error at -2 {{constexpr function's return type 'void' is not a literal type}}
+#endif
constexpr ~T(); // expected-error {{destructor cannot be marked constexpr}}
typedef NonLiteral F() const;
constexpr F NonLiteralReturn2; // ok until definition
@@ -49,12 +53,17 @@ struct T : SS, NonLiteral { // expected-
// - its function-body shall be = delete, = default,
constexpr int Deleted() const = delete;
- // It's not possible for the function-body to legally be "= default" here.
+ // It's not possible for the function-body to legally be "= default" here
+ // (that is, for a non-constructor function) in C++11.
// Other than constructors, only the copy- and move-assignment operators and
// destructor can be defaulted. Destructors can't be constexpr since they
// don't have a literal return type. Defaulted assignment operators can't be
// constexpr since they can't be const.
- constexpr T &operator=(const T&) = default; // expected-error {{an explicitly-defaulted copy assignment operator may not have 'const', 'constexpr' or 'volatile' qualifiers}} expected-warning {{C++1y}}
+ constexpr T &operator=(const T&) = default;
+#ifndef CXX1Y
+ // expected-error at -2 {{an explicitly-defaulted copy assignment operator may not have 'const', 'constexpr' or 'volatile' qualifiers}}
+ // expected-warning at -3 {{C++1y}}
+#endif
};
struct U {
constexpr U SelfReturn() const;
@@ -65,8 +74,8 @@ struct V : virtual U { // expected-note
constexpr int F() const { return 0; } // expected-error {{constexpr member function not allowed in struct with virtual base class}}
};
-// or a compound-statememt that contains only
-constexpr int AllowedStmts() {
+// or a compound-statememt that contains only [CXX11]
+constexpr int AllowedStmtsCXX11() {
// - null statements
;
@@ -91,34 +100,122 @@ constexpr int AllowedStmts() {
// - and exactly one return statement
return sizeof(K) + sizeof(C) + sizeof(K);
}
+
+// or a compound-statement that does not contain [CXX1Y]
+constexpr int DisallowedStmtsCXX1Y_1() {
+ // - an asm-definition
+ asm("int3"); // expected-error {{statement not allowed in constexpr function}}
+ return 0;
+}
+constexpr int DisallowedStmtsCXX1Y_2() {
+ // - a goto statement
+ goto x; // expected-error {{statement not allowed in constexpr function}}
+x:
+ return 0;
+}
+constexpr int DisallowedStmtsCXX1Y_3() {
+ // - a try-block,
+ try {} catch (...) {} // expected-error {{statement not allowed in constexpr function}}
+ return 0;
+}
+constexpr int DisallowedStmtsCXX1Y_4() {
+ // - a definition of a variable of non-literal type
+ NonLiteral nl; // expected-error {{variable of non-literal type 'NonLiteral' cannot be defined in a constexpr function}}
+ return 0;
+}
+constexpr int DisallowedStmtsCXX1Y_5() {
+ // - a definition of a variable of static storage duration
+ static constexpr int n = 123; // expected-error {{static variable not permitted in a constexpr function}}
+ return n;
+}
+constexpr int DisallowedStmtsCXX1Y_6() {
+ // - a definition of a variable of thread storage duration
+ thread_local constexpr int n = 123; // expected-error {{thread_local variable not permitted in a constexpr function}}
+ return n;
+}
+constexpr int DisallowedStmtsCXX1Y_7() {
+ // - a definition of a variable for which no initialization is performed
+ int n; // expected-error {{variables defined in a constexpr function must be initialized}}
+ return 0;
+}
+
constexpr int ForStmt() {
- for (int n = 0; n < 10; ++n) // expected-error {{statement not allowed in constexpr function}}
+ for (int n = 0; n < 10; ++n)
+#ifndef CXX1Y
+ // expected-error at -2 {{statement not allowed in constexpr function}}
+#else
+ // FIXME: Once we support evaluating a for-statement, this diagnostic should disappear.
+ // expected-error at -6 {{never produces a constant expression}}
+ // expected-note at -6 {{subexpression}}
+#endif
return 0;
}
constexpr int VarDecl() {
- constexpr int a = 0; // expected-error {{variables cannot be declared in a constexpr function}}
+ int a = 0;
+#ifndef CXX1Y
+ // expected-error at -2 {{variable declaration in a constexpr function is a C++1y extension}}
+#endif
+ return 0;
+}
+constexpr int ConstexprVarDecl() {
+ constexpr int a = 0;
+#ifndef CXX1Y
+ // expected-error at -2 {{variable declaration in a constexpr function is a C++1y extension}}
+#endif
return 0;
}
+constexpr int VarWithCtorDecl() {
+ Literal a;
+#ifndef CXX1Y
+ // expected-error at -2 {{variable declaration in a constexpr function is a C++1y extension}}
+#endif
+ return 0;
+}
+NonLiteral nl;
+constexpr NonLiteral &ExternNonLiteralVarDecl() {
+ extern NonLiteral nl;
+#ifndef CXX1Y
+ // expected-error at -2 {{variable declaration in a constexpr function is a C++1y extension}}
+#endif
+ return nl;
+}
+static_assert(&ExternNonLiteralVarDecl() == &nl, "");
constexpr int FuncDecl() {
- constexpr int ForwardDecl(int); // expected-error {{statement not allowed in constexpr function}}
+ constexpr int ForwardDecl(int);
+#ifndef CXX1Y
+ // expected-error at -2 {{use of this statement in a constexpr function is a C++1y extension}}
+#endif
return ForwardDecl(42);
}
constexpr int ClassDecl1() {
- typedef struct { } S1; // expected-error {{types cannot be defined in a constexpr function}}
+ typedef struct { } S1;
+#ifndef CXX1Y
+ // expected-error at -2 {{type definition in a constexpr function is a C++1y extension}}
+#endif
return 0;
}
constexpr int ClassDecl2() {
- using S2 = struct { }; // expected-error {{types cannot be defined in a constexpr function}}
+ using S2 = struct { };
+#ifndef CXX1Y
+ // expected-error at -2 {{type definition in a constexpr function is a C++1y extension}}
+#endif
return 0;
}
constexpr int ClassDecl3() {
- struct S3 { }; // expected-error {{types cannot be defined in a constexpr function}}
+ struct S3 { };
+#ifndef CXX1Y
+ // expected-error at -2 {{type definition in a constexpr function is a C++1y extension}}
+#endif
return 0;
}
constexpr int NoReturn() {} // expected-error {{no return statement in constexpr function}}
constexpr int MultiReturn() {
- return 0; // expected-note {{return statement}}
- return 0; // expected-error {{multiple return statements in constexpr function}}
+ return 0;
+ return 0;
+#ifndef CXX1Y
+ // expected-error at -2 {{multiple return statements in constexpr function}}
+ // expected-note at -4 {{return statement}}
+#endif
}
// - every constructor call and implicit conversion used in initializing the
@@ -153,3 +250,46 @@ namespace rdar13584715 {
}
}
}
+
+namespace std_example {
+ constexpr int square(int x) {
+ return x * x;
+ }
+ constexpr long long_max() {
+ return 2147483647;
+ }
+ constexpr int abs(int x) {
+ if (x < 0)
+#ifndef CXX1Y
+ // expected-error at -2 {{C++1y}}
+#endif
+ x = -x;
+ return x;
+ }
+ constexpr int first(int n) {
+ static int value = n; // expected-error {{static variable not permitted}}
+ return value;
+ }
+ constexpr int uninit() {
+ int a; // expected-error {{must be initialized}}
+ return a;
+ }
+ // FIXME: Once we support variable mutation, this can produce a
+ // constant expression.
+ constexpr int prev(int x) { // expected-error {{never produces a constant expression}}
+ return --x; // expected-note {{subexpression}}
+ }
+ constexpr int g(int x, int n) {
+ int r = 1;
+ while (--n > 0) r *= x;
+ return r;
+ }
+#ifndef CXX1Y
+ // expected-error at -5 {{C++1y}}
+ // expected-error at -5 {{statement not allowed}}
+#else
+ // FIXME: This should be allowed.
+ // expected-error at -10 {{never produces a constant}}
+ // expected-note at -9 {{subexpression}}
+#endif
+}
Modified: cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp (original)
+++ cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp Mon Apr 22 10:31:51 2013
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -verify -std=c++11 -fcxx-exceptions %s
+// RUN: %clang_cc1 -verify -std=c++11 -fcxx-exceptions -Werror=c++1y-extensions %s
+// RUN: %clang_cc1 -verify -std=c++1y -fcxx-exceptions -DCXX1Y %s
namespace N {
typedef char C;
@@ -82,26 +83,51 @@ struct V {
}
constexpr V(int(&)[1]) {
- for (int n = 0; n < 10; ++n) // expected-error {{statement not allowed in constexpr constructor}}
+ for (int n = 0; n < 10; ++n)
/**/;
+#ifndef CXX1Y
+ // expected-error at -3 {{statement not allowed in constexpr constructor}}
+#else
+ // FIXME: Once we support evaluating a for-statement, this diagnostic should disappear.
+ // expected-error at -7 {{never produces a constant expression}}
+ // expected-note at -7 {{subexpression}}
+#endif
}
constexpr V(int(&)[2]) {
- constexpr int a = 0; // expected-error {{variables cannot be declared in a constexpr constructor}}
+ constexpr int a = 0;
+#ifndef CXX1Y
+ // expected-error at -2 {{variable declaration in a constexpr constructor is a C++1y extension}}
+#endif
}
constexpr V(int(&)[3]) {
- constexpr int ForwardDecl(int); // expected-error {{statement not allowed in constexpr constructor}}
+ constexpr int ForwardDecl(int);
+#ifndef CXX1Y
+ // expected-error at -2 {{use of this statement in a constexpr constructor is a C++1y extension}}
+#endif
}
constexpr V(int(&)[4]) {
- typedef struct { } S1; // expected-error {{types cannot be defined in a constexpr constructor}}
+ typedef struct { } S1;
+#ifndef CXX1Y
+ // expected-error at -2 {{type definition in a constexpr constructor is a C++1y extension}}
+#endif
}
constexpr V(int(&)[5]) {
- using S2 = struct { }; // expected-error {{types cannot be defined in a constexpr constructor}}
+ using S2 = struct { };
+#ifndef CXX1Y
+ // expected-error at -2 {{type definition in a constexpr constructor is a C++1y extension}}
+#endif
}
constexpr V(int(&)[6]) {
- struct S3 { }; // expected-error {{types cannot be defined in a constexpr constructor}}
+ struct S3 { };
+#ifndef CXX1Y
+ // expected-error at -2 {{type definition in a constexpr constructor is a C++1y extension}}
+#endif
}
constexpr V(int(&)[7]) {
- return; // expected-error {{statement not allowed in constexpr constructor}}
+ return;
+#ifndef CXX1Y
+ // expected-error at -2 {{use of this statement in a constexpr constructor is a C++1y extension}}
+#endif
}
};
Modified: cfe/trunk/test/CXX/except/except.spec/p1.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/except/except.spec/p1.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/test/CXX/except/except.spec/p1.cpp (original)
+++ cfe/trunk/test/CXX/except/except.spec/p1.cpp Mon Apr 22 10:31:51 2013
@@ -55,7 +55,7 @@ namespace noex {
struct A {};
void g1() noexcept(A()); // expected-error {{not contextually convertible}}
- void g2(bool b) noexcept(b); // expected-error {{argument to noexcept specifier must be a constant expression}}
+ void g2(bool b) noexcept(b); // expected-error {{argument to noexcept specifier must be a constant expression}} expected-note {{read of non-const variable 'b'}} expected-note {{here}}
}
Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=180022&r1=180021&r2=180022&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original)
+++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Mon Apr 22 10:31:51 2013
@@ -1312,6 +1312,13 @@ namespace InvalidClasses {
}
}
+namespace NamespaceAlias {
+ constexpr int f() {
+ namespace NS = NamespaceAlias; // expected-warning {{use of this statement in a constexpr function is a C++1y extension}}
+ return &NS::f != nullptr;
+ }
+}
+
// Constructors can be implicitly constexpr, even for a non-literal type.
namespace ImplicitConstexpr {
struct Q { Q() = default; Q(const Q&) = default; Q(Q&&) = default; ~Q(); }; // expected-note 3{{here}}
Added: cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp?rev=180022&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp (added)
+++ cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp Mon Apr 22 10:31:51 2013
@@ -0,0 +1,126 @@
+// RUN: %clang_cc1 -std=c++1y -verify %s -fcxx-exceptions -triple=x86_64-linux-gnu
+
+struct S {
+ // dummy ctor to make this a literal type
+ constexpr S(int);
+
+ S();
+
+ int arr[10];
+
+ constexpr int &get(int n) { return arr[n]; }
+ constexpr const int &get(int n) const { return arr[n]; }
+};
+
+S s = S();
+const S &sr = s;
+static_assert(&s.get(4) - &sr.get(2) == 2, "");
+
+// Compound-statements can be used in constexpr functions.
+constexpr int e() {{{{}} return 5; }}
+static_assert(e() == 5, "");
+
+// Types can be defined in constexpr functions.
+constexpr int f() {
+ enum E { e1, e2, e3 };
+
+ struct S {
+ constexpr S(E e) : e(e) {}
+ constexpr int get() { return e; }
+ E e;
+ };
+
+ return S(e2).get();
+}
+static_assert(f() == 1, "");
+
+// Variables can be declared in constexpr functions.
+constexpr int g(int k) {
+ const int n = 9;
+ int k2 = k * k;
+ int k3 = k2 * k;
+ return 3 * k3 + 5 * k2 + n * k - 20;
+}
+static_assert(g(2) == 42, "");
+constexpr int h(int n) {
+ static const int m = n; // expected-error {{static variable not permitted in a constexpr function}}
+ return m;
+}
+constexpr int i(int n) {
+ thread_local const int m = n; // expected-error {{thread_local variable not permitted in a constexpr function}}
+ return m;
+}
+
+// if-statements can be used in constexpr functions.
+constexpr int j(int k) {
+ if (k == 5)
+ return 1;
+ if (k == 1)
+ return 5;
+ else {
+ if (int n = 2 * k - 4) {
+ return n + 1;
+ return 2;
+ }
+ }
+} // expected-note 2{{control reached end of constexpr function}}
+static_assert(j(0) == -3, "");
+static_assert(j(1) == 5, "");
+static_assert(j(2), ""); // expected-error {{constant expression}} expected-note {{in call to 'j(2)'}}
+static_assert(j(3) == 3, "");
+static_assert(j(4) == 5, "");
+static_assert(j(5) == 1, "");
+
+// There can be 0 return-statements.
+constexpr void k() {
+}
+
+// If the return type is not 'void', no return statements => never a constant
+// expression, so still diagnose that case.
+[[noreturn]] constexpr int fn() { // expected-error {{no return statement in constexpr function}}
+ fn();
+}
+
+// We evaluate the body of a constexpr constructor, to check for side-effects.
+struct U {
+ constexpr U(int n) {
+ if (j(n)) {} // expected-note {{in call to 'j(2)'}}
+ }
+};
+constexpr U u1{1};
+constexpr U u2{2}; // expected-error {{constant expression}} expected-note {{in call to 'U(2)'}}
+
+// We allow expression-statements.
+constexpr int l(bool b) {
+ if (b)
+ throw "invalid value for b!"; // expected-note {{subexpression not valid}}
+ return 5;
+}
+static_assert(l(false) == 5, "");
+static_assert(l(true), ""); // expected-error {{constant expression}} expected-note {{in call to 'l(true)'}}
+
+// Potential constant expression checking is still applied where possible.
+constexpr int htonl(int x) { // expected-error {{never produces a constant expression}}
+ typedef unsigned char uchar;
+ uchar arr[4] = { uchar(x >> 24), uchar(x >> 16), uchar(x >> 8), uchar(x) };
+ return *reinterpret_cast<int*>(arr); // expected-note {{reinterpret_cast is not allowed in a constant expression}}
+}
+
+constexpr int maybe_htonl(bool isBigEndian, int x) {
+ if (isBigEndian)
+ return x;
+
+ typedef unsigned char uchar;
+ uchar arr[4] = { uchar(x >> 24), uchar(x >> 16), uchar(x >> 8), uchar(x) };
+ return *reinterpret_cast<int*>(arr); // expected-note {{reinterpret_cast is not allowed in a constant expression}}
+}
+
+constexpr int swapped = maybe_htonl(false, 123); // expected-error {{constant expression}} expected-note {{in call}}
+
+namespace NS {
+ constexpr int n = 0;
+}
+constexpr int namespace_alias() {
+ namespace N = NS;
+ return N::n;
+}
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