[clang] [clang] Catch missing format attributes (PR #70024)

[Budimir Aranđelović via cfe-commits]

================
@@ -0,0 +1,132 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-format-attribute %s
+
+#include <iostream>
+#include <cstdarg>
+
+void f1(const std::string &str, ... /* args */)
+{
+    va_list args;
+    vscanf(str.c_str(), args); // no warning
+    vprintf(str.c_str(), args); // no warning
+}
+
+__attribute__((format(printf, 1, 2))) // expected-error: {{format argument not a string type}}
+void f2(const std::string &str, ... /* args */);
+
+void f3(std::string_view str, ... /* args */)
+{
+    va_list args;
+    vscanf(std::string(str).c_str(), args); // no warning
+    vprintf(std::string(str).c_str(), args); // no warning
+}
+
+__attribute__((format(printf, 1, 2))) // expected-error {{format argument not a string type}}
+void f4(std::string_view str, ... /* args */);
+
+void f5(const std::wstring &str, ... /* args */)
+{
+    va_list args;
+    vscanf((const char *)str.c_str(), args); // no warning
+    vprintf((const char *)str.c_str(), args); // no warning
+}
+
+__attribute__((format(printf, 1, 2))) // expected-error {{format argument not a string type}}
+void f6(const std::wstring &str, ... /* args */);
+
+void f7(std::wstring_view str, ... /* args */)
+{
+    va_list args;
+    vscanf((const char *) std::wstring(str).c_str(), args); // no warning
+    vprintf((const char *) std::wstring(str).c_str(), args); // no warning
+}
+
+__attribute__((format(printf, 1, 2))) // expected-error {{format argument not a string type}}
+void f8(std::wstring_view str, ... /* args */);
+
+void f9(const wchar_t *out, ... /* args */)
+{
+    va_list args;
+    vprintf(out, args); // expected-error {{no matching function for call to 'vprintf'}}
+    vscanf((const char *) out, args); // no warning
+    vscanf((char *) out, args); // no warning
+}
+
+__attribute__((format(printf, 1, 2))) // expected-error {{format argument not a string type}}
+void f10(const wchar_t *out, ... /* args */);
+
+void f11(const char16_t *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-error {{no matching function for call to 'vscanf'}}
+}
+
+__attribute__((format(printf, 1, 2))) // expected-error {{format argument not a string type}}
+void f12(const char16_t *out, ... /* args */);
+
+void f13(const char32_t *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-error {{no matching function for call to 'vscanf'}}
+}
+
+__attribute__((format(scanf, 1, 2))) // expected-error {{format argument not a string type}}
+void f14(const char32_t *out, ... /* args */);
+
+void f15(const char *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f15'}}
+}
+
+__attribute__((format(scanf, 1, 2)))
+void f16(const char *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // no warning
+}
+
+void f17(const unsigned char *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-error {{no matching function for call to 'vscanf'}}
+}
+
+__attribute__((format(scanf, 1, 2)))
+void f18(const unsigned char *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-error {{no matching function for call to 'vscanf'}}
+}
+
+void f19(const signed char *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-error {{no matching function for call to 'vscanf'}}
+}
+
+__attribute__((format(scanf, 1, 2)))
+void f20(const signed char *out, ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-error {{no matching function for call to 'vscanf'}}
+}
+
+void f21(const char out[], ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f21'}}
+}
+
+__attribute__((format(scanf, 1, 2)))
+void f22(const char out[], ... /* args */)
+{
+    va_list args;
+    vscanf(out, args); // no warning
+}
+
+template <int N>
+void func(char (&str)[N], ...)
+{
+    va_list args;
+    vprintf(str, args); // no warning
+}
----------------
budimirarandjelovicsyrmia wrote:

Added tests where function is member of a class/structure/union.

https://github.com/llvm/llvm-project/pull/70024