[Sema] Fix a crash when nonnull checking

darkbuck · darkbuck · commit ce38992a3079 · 2019-03-29T03:55:52.000Z
Summary: - If a parameter is used, nonnull checking needs function prototype to retrieve the corresponding parameter's attributes. However, at the prototype substitution phase when a template is being instantiated, expression may be created and checked without a fully specialized prototype. Under such a scenario, skip nonnull checking on that argument. Reviewers: rjmccall, tra, yaxunl Subscribers: javed.absar, kristof.beyls, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D59900 llvm-svn: 357236
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
@@ -11592,6 +11592,9 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
       }
 
       if (const auto *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) {
+        // Skip function template not specialized yet.
+        if (FD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)
+          return;
         auto ParamIter = llvm::find(FD->parameters(), PV);
         assert(ParamIter != FD->param_end());
         unsigned ParamNo = std::distance(FD->param_begin(), ParamIter);
diff --git a/clang/test/SemaCXX/pr30559.cpp b/clang/test/SemaCXX/pr30559.cpp
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only %s
+
+template < bool, class > struct A {};
+template < class, int > void f () {};
+template < class T, int >
+decltype (f < T, 1 >) f (T t, typename A < t == 0, int >::type) {};
+
+struct B {};
+
+int main ()
+{
+  f < B, 0 >;
+  return 0;
+}
+
+template <typename T>
+auto foo(T x) -> decltype((x == nullptr), *x) {
+  return *x;
+}
+
+void bar() {
+  foo(new int);
+}

Original file line number	Diff line number	Diff line change
`@@ -11592,6 +11592,9 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,`
`11592`	`11592`	`}`
`11593`	`11593`
`11594`	`11594`	`if (const auto *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) {`
	`11595`	`+ // Skip function template not specialized yet.`
	`11596`	`+ if (FD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)`
	`11597`	`+ return;`
`11595`	`11598`	`auto ParamIter = llvm::find(FD->parameters(), PV);`
`11596`	`11599`	`assert(ParamIter != FD->param_end());`
`11597`	`11600`	`unsigned ParamNo = std::distance(FD->param_begin(), ParamIter);`