From 9aaadab7d6ea587a7a12f684911271dc4f7a1e8b Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Wed, 15 Dec 2021 02:15:36 +0100
Subject: [PATCH] Check for most clang warnings in our headers in the test
 suite

Make allheaders unit test also enable -Wall, -Wextra and -Wpedantic for
clang to detect any warnings it might give in wx headers.

Don't use -Weverything because there are just too many warnings we'd
need to disable then.
---
 tests/allheaders.cpp | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/tests/allheaders.cpp b/tests/allheaders.cpp
index 1264104bbc..6295d897c1 100644
--- a/tests/allheaders.cpp
+++ b/tests/allheaders.cpp
@@ -18,7 +18,7 @@
     #define CHECK_GCC_VERSION(major, minor) 0
 #endif
 
-#if CHECK_GCC_VERSION(4, 6)
+#if CHECK_GCC_VERSION(4, 6) || defined(__clang__)
     // As above, we can't reuse wxCONCAT() and wxSTRINGIZE macros from wx/cpp.h
     // here, so define their equivalents here.
     #define CONCAT_HELPER(x, y) x ## y
@@ -27,10 +27,18 @@
     #define STRINGIZE_HELPER(x) #x
     #define STRINGIZE(x)        STRINGIZE_HELPER(x)
 
-    #define GCC_TURN_ON(warn) \
-        _Pragma(STRINGIZE(GCC diagnostic error STRINGIZE(CONCAT(-W,warn))))
-    #define GCC_TURN_OFF(warn) \
-        _Pragma(STRINGIZE(GCC diagnostic ignored STRINGIZE(CONCAT(-W,warn))))
+    #define WARNING_TURN_ON(comp, warn) \
+        _Pragma(STRINGIZE(comp diagnostic error STRINGIZE(CONCAT(-W,warn))))
+    #define WARNING_TURN_OFF(comp, warn) \
+        _Pragma(STRINGIZE(comp diagnostic ignored STRINGIZE(CONCAT(-W,warn))))
+
+    #if CHECK_GCC_VERSION(4, 6)
+        #define GCC_TURN_ON(warn) WARNING_TURN_ON(GCC, warn)
+        #define GCC_TURN_OFF(warn) WARNING_TURN_OFF(GCC, warn)
+    #elif defined(__clang__)
+        #define CLANG_TURN_ON(warn) WARNING_TURN_ON(clang, warn)
+        #define CLANG_TURN_OFF(warn) WARNING_TURN_OFF(clang, warn)
+    #endif
 #endif
 
 // We have to include this one first in order to check for wxUSE_XXX below.
@@ -374,6 +382,24 @@
     GCC_TURN_OFF(padded)
 #endif // gcc >= 4.6
 
+// Do the same for clang too except here we don't bother with the individual
+// warnings and just enable the usual ones because clang mostly includes all
+// the useful warnings in them anyhow.
+#ifdef CLANG_TURN_ON
+    CLANG_TURN_ON(all)
+    CLANG_TURN_ON(extra)
+    CLANG_TURN_ON(pedantic)
+
+    // We use long long, variadic macros and empty macro arguments (which are a
+    // C99 extension) even in C++98 builds.
+    #if __cplusplus < 201103L
+        CLANG_TURN_OFF(c++11-long-long)
+        CLANG_TURN_OFF(variadic-macros)
+        CLANG_TURN_OFF(c99-extensions)
+    #endif
+#endif // clang
+
+
 // ANSI build hasn't been updated to work without implicit wxString encoding
 // and never will be, as it will be removed soon anyhow. And in UTF-8-only
 // build we actually want to use implicit encoding (UTF-8).