Function with unparsed body is a definition
While a function body is being parsed, the function declaration is not considered
as a definition because it does not have a body yet. In some cases it leads to
incorrect interpretation, the case is presented in
https://bugs.llvm.org/show_bug.cgi?id=14785:
```
template<typename T> struct Somewhat {
void internal() const {}
friend void operator+(int const &, Somewhat<T> const &) {}
};
void operator+(int const &, Somewhat<char> const &x) { x.internal(); }
```
When statement `x.internal()` in the body of global `operator+` is parsed, the type
of `x` must be completed, so the instantiation of `Somewhat<char>` is started. It
instantiates the declaration of `operator+` defined inline, and makes a check for
redefinition. The check does not detect another definition because the declaration
of `operator+` is still not defining as does not have a body yet.
To solves this problem the function `isThisDeclarationADefinition` considers
a function declaration as a definition if it has flag `WillHaveBody` set.
This change fixes PR14785.
Differential Revision: https://reviews.llvm.org/D30375
This is a recommit of 305379, reverted in 305381, with small changes.
llvm-svn: 305903
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index b15c9d3..30552be 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -1874,7 +1874,7 @@
///
bool isThisDeclarationADefinition() const {
return IsDeleted || IsDefaulted || Body || IsLateTemplateParsed ||
- hasDefiningAttr();
+ WillHaveBody || hasDefiningAttr();
}
/// doesThisDeclarationHaveABody - Returns whether this specific
diff --git a/clang/lib/Sema/SemaCUDA.cpp b/clang/lib/Sema/SemaCUDA.cpp
index b938ac3..cac5f68 100644
--- a/clang/lib/Sema/SemaCUDA.cpp
+++ b/clang/lib/Sema/SemaCUDA.cpp
@@ -629,12 +629,6 @@
// emitted, because (say) the definition could include "inline".
FunctionDecl *Def = FD->getDefinition();
- // We may currently be parsing the body of FD, in which case
- // FD->getDefinition() will be null, but we still want to treat FD as though
- // it's a definition.
- if (!Def && FD->willHaveBody())
- Def = FD;
-
if (Def &&
!isDiscardableGVALinkage(S.getASTContext().GetGVALinkageForFunction(Def)))
return true;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index d6164b3..2f78d06 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12232,6 +12232,7 @@
if (FD) {
FD->setBody(Body);
+ FD->setWillHaveBody(false);
if (getLangOpts().CPlusPlus14) {
if (!FD->isInvalidDecl() && Body && !FD->isDependentContext() &&
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 844299b..0b46e15 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -13878,6 +13878,9 @@
return;
}
+ // Deleted function does not have a body.
+ Fn->setWillHaveBody(false);
+
if (const FunctionDecl *Prev = Fn->getPreviousDecl()) {
// Don't consider the implicit declaration we generate for explicit
// specializations. FIXME: Do not generate these implicit declarations.
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index c58122c..4797602 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1782,6 +1782,9 @@
Previous.clear();
}
+ if (isFriend)
+ Function->setObjectOfFriendDecl();
+
SemaRef.CheckFunctionDeclaration(/*Scope*/ nullptr, Function, Previous,
isExplicitSpecialization);
diff --git a/clang/test/SemaCXX/friend2.cpp b/clang/test/SemaCXX/friend2.cpp
index 347af0d..d1d4b62 100644
--- a/clang/test/SemaCXX/friend2.cpp
+++ b/clang/test/SemaCXX/friend2.cpp
@@ -170,3 +170,40 @@
template class Test<int>;
}
+
+namespace pr14785 {
+template<typename T>
+struct Somewhat {
+ void internal() const { }
+ friend void operator+(int const &, Somewhat<T> const &) {} // expected-error{{redefinition of 'operator+'}}
+};
+
+void operator+(int const &, Somewhat<char> const &x) { // expected-note {{previous definition is here}}
+ x.internal(); // expected-note{{in instantiation of template class 'pr14785::Somewhat<char>' requested here}}
+}
+}
+
+namespace D30375 {
+template <typename K> struct B {
+ template <typename A> bool insert(A &);
+};
+
+template <typename K>
+template <typename A> bool B<K>::insert(A &x) { return x < x; }
+
+template <typename K> class D {
+ B<K> t;
+
+public:
+ K x;
+ bool insert() { return t.insert(x); }
+ template <typename K1> friend bool operator<(const D<K1> &, const D<K1> &);
+};
+
+template <typename K> bool operator<(const D<K> &, const D<K> &);
+
+void func() {
+ D<D<int>> cache;
+ cache.insert();
+}
+}