r264471 - Don't warn on "use" of undefined inline function that isn't actually an ODR
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Fri Mar 25 15:29:27 PDT 2016
Author: rsmith
Date: Fri Mar 25 17:29:27 2016
New Revision: 264471
URL: http://llvm.org/viewvc/llvm-project?rev=264471&view=rev
Log:
Don't warn on "use" of undefined inline function that isn't actually an ODR
use. In order for this to fire, the function needed to be a templated function
marked 'constexpr' and declared but not defined. This weird pattern appears in
libstdc++'s alloc_traits.h.
Modified:
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/test/SemaCXX/undefined-inline.cpp
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=264471&r1=264470&r2=264471&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Fri Mar 25 17:29:27 2016
@@ -3593,9 +3593,15 @@ public:
// for expressions referring to a decl; these exist because odr-use marking
// needs to be delayed for some constant variables when we build one of the
// named expressions.
- void MarkAnyDeclReferenced(SourceLocation Loc, Decl *D, bool OdrUse);
+ //
+ // MightBeOdrUse indicates whether the use could possibly be an odr-use, and
+ // should usually be true. This only needs to be set to false if the lack of
+ // odr-use cannot be determined from the current context (for instance,
+ // because the name denotes a virtual function and was written without an
+ // explicit nested-name-specifier).
+ void MarkAnyDeclReferenced(SourceLocation Loc, Decl *D, bool MightBeOdrUse);
void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
- bool OdrUse = true);
+ bool MightBeOdrUse = true);
void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
void MarkDeclRefReferenced(DeclRefExpr *E);
void MarkMemberReferenced(MemberExpr *E);
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=264471&r1=264470&r2=264471&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Fri Mar 25 17:29:27 2016
@@ -12770,7 +12770,7 @@ static bool IsPotentiallyEvaluatedContex
/// \brief Mark a function referenced, and check whether it is odr-used
/// (C++ [basic.def.odr]p2, C99 6.9p3)
void Sema::MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
- bool OdrUse) {
+ bool MightBeOdrUse) {
assert(Func && "No function?");
Func->setReferenced();
@@ -12783,8 +12783,8 @@ void Sema::MarkFunctionReferenced(Source
// We (incorrectly) mark overload resolution as an unevaluated context, so we
// can just check that here. Skip the rest of this function if we've already
// marked the function as used.
- if (Func->isUsed(/*CheckUsedAttr=*/false) ||
- !IsPotentiallyEvaluatedContext(*this)) {
+ bool OdrUse = MightBeOdrUse && IsPotentiallyEvaluatedContext(*this);
+ if (Func->isUsed(/*CheckUsedAttr=*/false) || !OdrUse) {
// C++11 [temp.inst]p3:
// Unless a function template specialization has been explicitly
// instantiated or explicitly specialized, the function template
@@ -12873,8 +12873,6 @@ void Sema::MarkFunctionReferenced(Source
if (FPT && isUnresolvedExceptionSpec(FPT->getExceptionSpecType()))
ResolveExceptionSpec(Loc, FPT);
- if (!OdrUse) return;
-
// Implicit instantiation of function templates and member functions of
// class templates.
if (Func->isImplicitlyInstantiable()) {
@@ -12922,10 +12920,12 @@ void Sema::MarkFunctionReferenced(Source
// Walk redefinitions, as some of them may be instantiable.
for (auto i : Func->redecls()) {
if (!i->isUsed(false) && i->isImplicitlyInstantiable())
- MarkFunctionReferenced(Loc, i);
+ MarkFunctionReferenced(Loc, i, OdrUse);
}
}
+ if (!OdrUse) return;
+
// Keep track of used but undefined functions.
if (!Func->isDefined()) {
if (mightHaveNonExternalLinkage(Func))
@@ -13800,13 +13800,13 @@ void Sema::MarkVariableReferenced(Source
}
static void MarkExprReferenced(Sema &SemaRef, SourceLocation Loc,
- Decl *D, Expr *E, bool OdrUse) {
+ Decl *D, Expr *E, bool MightBeOdrUse) {
if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
DoMarkVarDeclReferenced(SemaRef, Loc, Var, E);
return;
}
- SemaRef.MarkAnyDeclReferenced(Loc, D, OdrUse);
+ SemaRef.MarkAnyDeclReferenced(Loc, D, MightBeOdrUse);
// If this is a call to a method via a cast, also mark the method in the
// derived class used in case codegen can devirtualize the call.
@@ -13828,7 +13828,7 @@ static void MarkExprReferenced(Sema &Sem
CXXMethodDecl *DM = MD->getCorrespondingMethodInClass(MostDerivedClassDecl);
if (!DM || DM->isPure())
return;
- SemaRef.MarkAnyDeclReferenced(Loc, DM, OdrUse);
+ SemaRef.MarkAnyDeclReferenced(Loc, DM, MightBeOdrUse);
}
/// \brief Perform reference-marking and odr-use handling for a DeclRefExpr.
@@ -13851,30 +13851,31 @@ void Sema::MarkMemberReferenced(MemberEx
// overload resolution when referred to from a potentially-evaluated
// expression, is odr-used, unless it is a pure virtual function and its
// name is not explicitly qualified.
- bool OdrUse = true;
+ bool MightBeOdrUse = true;
if (E->performsVirtualDispatch(getLangOpts())) {
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(E->getMemberDecl()))
if (Method->isPure())
- OdrUse = false;
+ MightBeOdrUse = false;
}
SourceLocation Loc = E->getMemberLoc().isValid() ?
E->getMemberLoc() : E->getLocStart();
- MarkExprReferenced(*this, Loc, E->getMemberDecl(), E, OdrUse);
+ MarkExprReferenced(*this, Loc, E->getMemberDecl(), E, MightBeOdrUse);
}
/// \brief Perform marking for a reference to an arbitrary declaration. It
/// marks the declaration referenced, and performs odr-use checking for
/// functions and variables. This method should not be used when building a
/// normal expression which refers to a variable.
-void Sema::MarkAnyDeclReferenced(SourceLocation Loc, Decl *D, bool OdrUse) {
- if (OdrUse) {
+void Sema::MarkAnyDeclReferenced(SourceLocation Loc, Decl *D,
+ bool MightBeOdrUse) {
+ if (MightBeOdrUse) {
if (auto *VD = dyn_cast<VarDecl>(D)) {
MarkVariableReferenced(Loc, VD);
return;
}
}
if (auto *FD = dyn_cast<FunctionDecl>(D)) {
- MarkFunctionReferenced(Loc, FD, OdrUse);
+ MarkFunctionReferenced(Loc, FD, MightBeOdrUse);
return;
}
D->setReferenced();
Modified: cfe/trunk/test/SemaCXX/undefined-inline.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/undefined-inline.cpp?rev=264471&r1=264470&r2=264471&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/undefined-inline.cpp (original)
+++ cfe/trunk/test/SemaCXX/undefined-inline.cpp Fri Mar 25 17:29:27 2016
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -triple i686-pc-win32 -verify %s
+// RUN: %clang_cc1 -fsyntax-only -triple i686-pc-win32 -verify -std=c++11 %s
// PR14993
namespace test1 {
@@ -61,3 +61,8 @@ namespace test11 {
inline void bar() __attribute__((dllimport));
void test() { foo(); bar(); }
}
+
+namespace test12 {
+ template<typename> constexpr int _S_chk(int *);
+ decltype(_S_chk<int>(nullptr)) n;
+}
More information about the cfe-commits
mailing list