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/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);