Correct handling of _Pragma macro inside a macro argument.

If we are pre-expanding a macro argument don't actually "activate"
the pragma at that point, activate the pragma whenever we encounter
it again in the token stream.
This ensures that we will activate it in the correct location
or that we will ignore it if it never enters the token stream, e.g:

     \#define EMPTY(x)
     \#define INACTIVE(x) EMPTY(x)
     INACTIVE(_Pragma("clang diagnostic ignored \"-Wconversion\""))

This also fixes the crash in rdar://11168596.

llvm-svn: 153959

1 files changed, 35 insertions, 0 deletions

diff --git a/clang/test/Preprocessor/_Pragma-in-macro-arg.c b/clang/test/Preprocessor/_Pragma-in-macro-arg.c
new file mode 100644
index 00000000000..99a33a9e1b3
--- /dev/null
+++ b/clang/test/Preprocessor/_Pragma-in-macro-arg.c
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 %s -verify -Wconversion
+
+// Don't crash (rdar://11168596)
+#define A(desc) _Pragma("clang diagnostic push")  _Pragma("clang diagnostic ignored \"-Wparentheses\"") _Pragma("clang diagnostic pop")
+#define B(desc) A(desc)
+B(_Pragma("clang diagnostic ignored \"-Wparentheses\""))
+
+
+#define EMPTY(x)
+#define INACTIVE(x) EMPTY(x)
+
+#define ID(x) x
+#define ACTIVE(x) ID(x)
+
+// This should be ignored..
+INACTIVE(_Pragma("clang diagnostic ignored \"-Wconversion\""))
+
+#define IGNORE_CONV _Pragma("clang diagnostic ignored \"-Wconversion\"")
+
+// ..as should this.
+INACTIVE(IGNORE_CONV)
+
+#define IGNORE_POPPUSH(Pop, Push, W, D) Push W D Pop
+IGNORE_POPPUSH(_Pragma("clang diagnostic pop"), _Pragma("clang diagnostic push"),
+               _Pragma("clang diagnostic ignored \"-Wconversion\""), int q = (double)1.0);
+
+int x1 = (double)1.0; // expected-warning {{implicit conversion}}
+
+ACTIVE(_Pragma) ("clang diagnostic ignored \"-Wconversion\"")) // expected-error {{_Pragma takes a parenthesized string literal}} \
+                                      expected-error {{expected identifier or '('}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+
+// This should disable the warning.
+ACTIVE(IGNORE_CONV)
+
+int x2 = (double)1.0;