From: Marek Polacek <polacek@redhat.com>
Date: Mon, 26 Sep 2016 15:53:28 +0000 (+0000)
Subject: c-lex.c (c_common_has_attribute): Handle attribute fallthrough.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c6147dc433015793d92602811e585b83c9018bc2;p=gcc.git

c-lex.c (c_common_has_attribute): Handle attribute fallthrough.

	* c-lex.c (c_common_has_attribute): Handle attribute fallthrough.

	* system.h: Use __has_attribute to check whether the fallthrough
	attribute is supported.

	* g++.dg/cpp1z/feat-cxx1z.C: Test attribute fallthrough.

From-SVN: r240499
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9427b506007..f7122e258d1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2016-09-26  Marek Polacek  <polacek@redhat.com>
+
+	* system.h: Use __has_attribute to check whether the fallthrough
+	attribute is supported.
+
 2016-09-26  Marek Polacek  <polacek@redhat.com>
 
 	* ipa-inline-analysis.c (find_foldable_builtin_expect): Use
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index cd3eeab02bd..6eec8958902 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,7 @@
+2016-09-26  Marek Polacek  <polacek@redhat.com>
+
+	* c-lex.c (c_common_has_attribute): Handle attribute fallthrough.
+
 2016-09-26  Marek Polacek  <polacek@redhat.com>
 
 	PR c/7652
diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c
index 829c18b26a4..5c6496ebecf 100644
--- a/gcc/c-family/c-lex.c
+++ b/gcc/c-family/c-lex.c
@@ -350,7 +350,8 @@ c_common_has_attribute (cpp_reader *pfile)
 	      else if (is_attribute_p ("deprecated", attr_name))
 		result = 201309;
 	      else if (is_attribute_p ("maybe_unused", attr_name)
-		       || is_attribute_p ("nodiscard", attr_name))
+		       || is_attribute_p ("nodiscard", attr_name)
+		       || is_attribute_p ("fallthrough", attr_name))
 		result = 201603;
 	      if (result)
 		attr_name = NULL_TREE;
diff --git a/gcc/system.h b/gcc/system.h
index 8ca71cf0f0e..0952e4f6e8f 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -746,8 +746,12 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
 #define gcc_unreachable() (fancy_abort (__FILE__, __LINE__, __FUNCTION__))
 #endif
 
-#if GCC_VERSION >= 7000
-# define gcc_fallthrough() __attribute__((fallthrough))
+#if GCC_VERSION >= 7000 && defined(__has_attribute)
+# if __has_attribute(fallthrough)
+#  define gcc_fallthrough() __attribute__((fallthrough))
+# else
+#  define gcc_fallthrough()
+# endif
 #else
 # define gcc_fallthrough()
 #endif
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f8567e1a53c..0692c017ef9 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2016-09-26  Marek Polacek  <polacek@redhat.com>
+
+	* g++.dg/cpp1z/feat-cxx1z.C: Test attribute fallthrough.
+
 2016-09-26  Martin Liska  <mliska@suse.cz>
 
 	* c-c++-common/ubsan/sanitize-recover-1.c: New test.
diff --git a/gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C b/gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C
index 982572e65cc..71c8c7d3768 100644
--- a/gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C
+++ b/gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C
@@ -370,6 +370,12 @@
 #    error "__has_cpp_attribute(nodiscard) != 201603"
 #  endif
 
+#  if ! __has_cpp_attribute(fallthrough)
+#    error "__has_cpp_attribute(fallthrough)"
+#  elif __has_cpp_attribute(fallthrough) != 201603
+#    error "__has_cpp_attribute(fallthrough) != 201603"
+#  endif
+
 #else
 #  error "__has_cpp_attribute"
 #endif