Properly implement warn_unused_result checking for classes/structs.
The previous implementation would copy the attribute from the class to
functions that have the class as their return type when the functions
are first declared. This proved to have two flaws:
1) if the class is forward-declared without the attribute and a
function or method with the class as a its return type is declared,
and afterward the class is defined with warn_unused_result, the
function or method would never inherit the attribute, and
2) the check simply failed for functions and methods that are part of
a template instantiation, regardless of whether the class with
warn_unused_result is part of a specific instantiation or part of
the template itself (presumably because those function/method
declaration does not hit the same code path as a non-template one
and so never inherits the attribute).
The new approach is to instead modify the two places where a function or
method call is checked for the warn_unused_result attribute on the decl
by extending the checks to also look for the attribute on the decl's
return type.
Additionally, the check for return types that have the warn_unused_result
now excludes pointers and references to such types, as such return types do
not necessarily imply a transfer of ownership for the underlying object
being referred to by the return value. This does not change the behavior
of functions that are directly given the warn_unused_result attribute.
llvm-svn: 234526
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 69e4457..2ae73de 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2822,6 +2822,18 @@
return RTRange;
}
+bool FunctionDecl::hasUnusedResultAttr() const {
+ QualType RetType = getReturnType();
+ if (RetType->isRecordType()) {
+ const CXXRecordDecl *Ret = RetType->getAsCXXRecordDecl();
+ const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(this);
+ if (Ret && Ret->hasAttr<WarnUnusedResultAttr>() &&
+ !(MD && MD->getCorrespondingMethodInClass(Ret, true)))
+ return true;
+ }
+ return hasAttr<WarnUnusedResultAttr>();
+}
+
/// \brief For an inline function definition in C, or for a gnu_inline function
/// in C++, determine whether the definition will be externally visible.
///