Consolidate and improve the handling of built-in feature-like macros

Summary:
The parsing logic has been separated out from the macro implementation logic, leading to a number of improvements:

* Gracefully handle unexpected/invalid tokens, too few, too many and nested parameters
* Provide consistent behaviour between all built-in feature-like macros
* Simplify the implementation of macro logic
* Fix __is_identifier to correctly return '0' for non-identifiers

Reviewers: doug.gregor, rsmith

Subscribers: rsmith, cfe-commits

Differential Revision: http://reviews.llvm.org/D17149

llvm-svn: 265381

4 files changed, 49 insertions, 8 deletions

diff --git a/clang/test/Preprocessor/feature_tests.c b/clang/test/Preprocessor/feature_tests.c
index fbde6a65476..52a1f17cdd4 100644
--- a/clang/test/Preprocessor/feature_tests.c
+++ b/clang/test/Preprocessor/feature_tests.c
@@ -55,8 +55,50 @@
 #endif
 
 #ifdef VERIFY
-// expected-error@+2 {{builtin feature check macro requires a parenthesized identifier}}
-// expected-error@+1 {{expected value in expression}}
+// expected-error@+1 {{builtin feature check macro requires a parenthesized identifier}}
 #if __has_feature('x')
 #endif
+
+// The following are not identifiers:
+_Static_assert(!__is_identifier("string"), "oops");
+_Static_assert(!__is_identifier('c'), "oops");
+_Static_assert(!__is_identifier(123), "oops");
+_Static_assert(!__is_identifier(int), "oops");
+
+// The following are:
+_Static_assert(__is_identifier(abc /* comment */), "oops");
+_Static_assert(__is_identifier /* comment */ (xyz), "oops");
+
+// expected-error@+1 {{too few arguments}}
+#if __is_identifier()
+#endif
+
+// expected-error@+1 {{too many arguments}}
+#if __is_identifier(,())
+#endif
+
+// expected-error@+1 {{missing ')' after 'abc'}} 
+#if __is_identifier(abc xyz) // expected-note {{to match this '('}}
+#endif
+
+// expected-error@+1 {{missing ')' after 'abc'}} 
+#if __is_identifier(abc())   // expected-note {{to match this '('}}
+#endif
+
+// expected-error@+1 {{missing ')' after '.'}} 
+#if __is_identifier(.abc)    // expected-note {{to match this '('}}
+#endif
+
+// expected-error@+1 {{nested parentheses not permitted in '__is_identifier'}} 
+#if __is_identifier((abc))
+#endif
+
+// expected-error@+1 {{missing '(' after '__is_identifier'}} expected-error@+1 {{expected value}}
+#if __is_identifier
+#endif
+
+// expected-error@+1 {{unterminated}} expected-error@+1 {{expected value}}
+#if __is_identifier(
+#endif
+
 #endif
diff --git a/clang/test/Preprocessor/invalid-__has_warning1.c b/clang/test/Preprocessor/invalid-__has_warning1.c
index b6a0b2e8ee3..5e4f12f5699 100644
--- a/clang/test/Preprocessor/invalid-__has_warning1.c
+++ b/clang/test/Preprocessor/invalid-__has_warning1.c
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -verify %s
 
 // These must be the last lines in this test.
-// expected-error@+1{{expected string literal}} expected-error@+1 2{{expected}}
+// expected-error@+1{{unterminated}} expected-error@+1 2{{expected}}
 int i = __has_warning(
diff --git a/clang/test/Preprocessor/invalid-__has_warning2.c b/clang/test/Preprocessor/invalid-__has_warning2.c
index 8aba530c875..f54ff479931 100644
--- a/clang/test/Preprocessor/invalid-__has_warning2.c
+++ b/clang/test/Preprocessor/invalid-__has_warning2.c
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -verify %s
 
 // These must be the last lines in this test.
-// expected-error@+1{{expected string literal}} expected-error@+1{{expected}}
+// expected-error@+1{{too few arguments}}
 int i = __has_warning();
diff --git a/clang/test/Preprocessor/warning_tests.c b/clang/test/Preprocessor/warning_tests.c
index c0c22ef2d71..1f2e884a588 100644
--- a/clang/test/Preprocessor/warning_tests.c
+++ b/clang/test/Preprocessor/warning_tests.c
@@ -12,7 +12,7 @@
 #endif
 
 // expected-error@+2 {{expected string literal in '__has_warning'}}
-// expected-error@+1 {{expected value in expression}}
+// expected-error@+1 {{missing ')'}} expected-note@+1 {{match}}
 #if __has_warning(-Wfoo)
 #endif
 
@@ -22,8 +22,7 @@
 #warning Not a valid warning flag
 #endif
 
-// expected-error@+2 {{builtin warning check macro requires a parenthesized string}}
-// expected-error@+1 {{invalid token}}
+// expected-error@+1 {{missing '(' after '__has_warning'}}
 #if __has_warning "not valid"
 #endif
 
@@ -33,7 +32,7 @@
 
 #define MY_ALIAS "-Wparentheses"
 
-// expected-error@+1 2{{expected}}
+// expected-error@+1 {{expected}}
 #if __has_warning(MY_ALIAS)
 #error Alias expansion not allowed
 #endif