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-rw-r--r--clang/include/clang/AST/Decl.h7
-rw-r--r--clang/lib/AST/Decl.cpp12
-rw-r--r--clang/lib/AST/Expr.cpp6
-rw-r--r--clang/lib/Sema/SemaDecl.cpp15
-rw-r--r--clang/lib/Sema/SemaStmt.cpp4
-rw-r--r--clang/test/SemaCXX/warn-unused-result.cpp23
6 files changed, 49 insertions, 18 deletions
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 3e3d79ff29e..f8e17268e6c 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -1965,6 +1965,13 @@ public:
return getType()->getAs<FunctionType>()->getCallResultType(getASTContext());
}
+ /// \brief Returns true if this function or its return type has the
+ /// warn_unused_result attribute. If the return type has the attribute and
+ /// this function is a method of the return type's class, then false will be
+ /// returned to avoid spurious warnings on member methods such as assignment
+ /// operators.
+ bool hasUnusedResultAttr() const;
+
/// \brief Returns the storage class as written in the source. For the
/// computed linkage of symbol, see getLinkage.
StorageClass getStorageClass() const { return StorageClass(SClass); }
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 69e44573dc6..2ae73de5074 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2822,6 +2822,18 @@ SourceRange FunctionDecl::getReturnTypeSourceRange() const {
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.
///
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index d4ec2714d59..76a4da2371b 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -2161,12 +2161,16 @@ bool Expr::isUnusedResultAWarning(const Expr *&WarnE, SourceLocation &Loc,
// If this is a direct call, get the callee.
const CallExpr *CE = cast<CallExpr>(this);
if (const Decl *FD = CE->getCalleeDecl()) {
+ const FunctionDecl *Func = dyn_cast<FunctionDecl>(FD);
+ bool HasWarnUnusedResultAttr = Func ? Func->hasUnusedResultAttr()
+ : FD->hasAttr<WarnUnusedResultAttr>();
+
// If the callee has attribute pure, const, or warn_unused_result, warn
// about it. void foo() { strlen("bar"); } should warn.
//
// Note: If new cases are added here, DiagnoseUnusedExprResult should be
// updated to match for QoI.
- if (FD->hasAttr<WarnUnusedResultAttr>() ||
+ if (HasWarnUnusedResultAttr ||
FD->hasAttr<PureAttr>() || FD->hasAttr<ConstAttr>()) {
WarnE = this;
Loc = CE->getCallee()->getLocStart();
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index ce183d0adf4..1bad38f53b8 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7489,23 +7489,10 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
// Handle attributes.
ProcessDeclAttributes(S, NewFD, D);
- QualType RetType = NewFD->getReturnType();
- const CXXRecordDecl *Ret = RetType->isRecordType() ?
- RetType->getAsCXXRecordDecl() : RetType->getPointeeCXXRecordDecl();
- if (!NewFD->isInvalidDecl() && !NewFD->hasAttr<WarnUnusedResultAttr>() &&
- Ret && Ret->hasAttr<WarnUnusedResultAttr>()) {
- const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
- // Attach WarnUnusedResult to functions returning types with that attribute.
- // Don't apply the attribute to that type's own non-static member functions
- // (to avoid warning on things like assignment operators)
- if (!MD || MD->getParent() != Ret)
- NewFD->addAttr(WarnUnusedResultAttr::CreateImplicit(Context));
- }
-
if (getLangOpts().OpenCL) {
// OpenCL v1.1 s6.5: Using an address space qualifier in a function return
// type declaration will generate a compilation error.
- unsigned AddressSpace = RetType.getAddressSpace();
+ unsigned AddressSpace = NewFD->getReturnType().getAddressSpace();
if (AddressSpace == LangAS::opencl_local ||
AddressSpace == LangAS::opencl_global ||
AddressSpace == LangAS::opencl_constant) {
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 5774f53c060..8b174f8d922 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -239,7 +239,9 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
// is written in a macro body, only warn if it has the warn_unused_result
// attribute.
if (const Decl *FD = CE->getCalleeDecl()) {
- if (FD->hasAttr<WarnUnusedResultAttr>()) {
+ const FunctionDecl *Func = dyn_cast<FunctionDecl>(FD);
+ if (Func ? Func->hasUnusedResultAttr()
+ : FD->hasAttr<WarnUnusedResultAttr>()) {
Diag(Loc, diag::warn_unused_result) << R1 << R2;
return;
}
diff --git a/clang/test/SemaCXX/warn-unused-result.cpp b/clang/test/SemaCXX/warn-unused-result.cpp
index 7bdb4245a95..01bc457ec20 100644
--- a/clang/test/SemaCXX/warn-unused-result.cpp
+++ b/clang/test/SemaCXX/warn-unused-result.cpp
@@ -44,6 +44,12 @@ void bah() {
}
namespace warn_unused_CXX11 {
+class Status;
+class Foo {
+ public:
+ Status doStuff();
+};
+
struct [[clang::warn_unused_result]] Status {
bool ok() const;
Status& operator=(const Status& x);
@@ -73,10 +79,23 @@ void lazy() {
(void)DoYetAnotherThing();
DoSomething(); // expected-warning {{ignoring return value}}
- DoSomethingElse(); // expected-warning {{ignoring return value}}
- DoAnotherThing(); // expected-warning {{ignoring return value}}
+ DoSomethingElse();
+ DoAnotherThing();
DoYetAnotherThing();
}
+
+template <typename T>
+class [[clang::warn_unused_result]] StatusOr {
+};
+StatusOr<int> doit();
+void test() {
+ Foo f;
+ f.doStuff(); // expected-warning {{ignoring return value}}
+ doit(); // expected-warning {{ignoring return value}}
+
+ auto func = []() { return Status(); };
+ func(); // expected-warning {{ignoring return value}}
+}
}
namespace PR17587 {
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