Add a predefine __WINT_UNSIGNED__, similar to __WCHAR_UNSIGNED__, and test them both for ARM and X86.

Use this to fully fix Sema/format-strings.c for non-x86 platforms.

Reviewed by Chandler on IRC.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156169 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/InitPreprocessor.cpp b/lib/Frontend/InitPreprocessor.cpp
index 4df7cfd..3d9d131 100644
--- a/lib/Frontend/InitPreprocessor.cpp
+++ b/lib/Frontend/InitPreprocessor.cpp
@@ -497,6 +497,9 @@
   if (!LangOpts.CharIsSigned)
     Builder.defineMacro("__CHAR_UNSIGNED__");
 
+  if (!TargetInfo::isTypeSigned(TI.getWCharType()))
+    Builder.defineMacro("__WCHAR_UNSIGNED__");
+
   if (!TargetInfo::isTypeSigned(TI.getWIntType()))
     Builder.defineMacro("__WINT_UNSIGNED__");
 
diff --git a/test/Lexer/wchar-signedness.c b/test/Lexer/wchar-signedness.c
new file mode 100644
index 0000000..fea0eca
--- /dev/null
+++ b/test/Lexer/wchar-signedness.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fsyntax-only -dM -E %s -triple x86_64-none-linux-gnu | FileCheck %s --check-prefix=X86
+// RUN: %clang_cc1 -fsyntax-only -dM -E %s -triple armv7-none-eabi | FileCheck %s --check-prefix=ARM
+
+// CHECK-X86-NOT: #define __WCHAR_UNSIGNED__
+// CHECK-X86: #define __WINT_UNSIGNED__ 1
+
+// CHECK-ARM: #define __WCHAR_UNSIGNED__ 1
+// CHECK-ARM-NOT: #define __WINT_UNSIGNED__ 1
diff --git a/test/Sema/format-strings.c b/test/Sema/format-strings.c
index d1dca7e..5d8e4cb 100644
--- a/test/Sema/format-strings.c
+++ b/test/Sema/format-strings.c
@@ -339,7 +339,12 @@
   printf("%lc", 1.0); // expected-warning{{the argument has type 'double'}}
   printf("%lc", (char) 1); // no-warning
   printf("%lc", &c); // expected-warning{{the argument has type 'wint_t *'}}
+  // If wint_t and wchar_t are the same width and wint_t is signed where
+  // wchar_t is unsigned, an implicit conversion isn't possible.
+#if defined(__WINT_UNSIGNED__) || !defined(__WCHAR_UNSIGNED__) ||   \
+  __WINT_WIDTH__ > __WCHAR_WIDTH__
   printf("%lc", c2); // no-warning
+#endif
 }
 
 // <rdar://problem/8269537> -Wformat-security says NULL is not a string literal