nobu	2013-11-04 10:08:21 +0900 (Mon, 04 Nov 2013)

  New Revision: 43522

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=rev&revision=43522

  Log:
    eval_intern.h: avoid undefined behavior of setjmp
    
    * eval_intern.h (TH_EXEC_TAG, TH_JUMP_TAG): get rid of undefined
      behavior of setjmp() in rhs of assignment expression.
      [ISO/IEC 9899:1999] 7.13.1.1

  Modified files:
    trunk/ChangeLog
    trunk/eval_intern.h
Index: eval_intern.h
===================================================================
--- eval_intern.h	(revision 43521)
+++ eval_intern.h	(revision 43522)
@@ -108,14 +108,33 @@ extern int select_large_fdset(int, fd_se https://github.com/ruby/ruby/blob/trunk/eval_intern.h#L108
 #define PUSH_TAG() TH_PUSH_TAG(GET_THREAD())
 #define POP_TAG()      TH_POP_TAG()
 
-#define TH_EXEC_TAG() ruby_setjmp(_th->tag->buf)
+/* clear th->state, and return the value */
+static inline int
+ruby_threadptr_tag_state(rb_thread_t *th)
+{
+    int state = th->state;
+    th->state = 0;
+    return state;
+}
+
+NORETURN(static inline void ruby_threadptr_tag_jump(rb_thread_t *, int));
+static inline void
+ruby_threadptr_tag_jump(rb_thread_t *th, int st)
+{
+    ruby_longjmp(th->tag->buf, (th->state = st));
+}
+
+/*
+  setjmp() in assignment expression rhs is undefined behavior
+  [ISO/IEC 9899:1999] 7.13.1.1
+*/
+#define TH_EXEC_TAG() \
+    (ruby_setjmp(_th->tag->buf) ? ruby_threadptr_tag_state(_th) : 0)
 
 #define EXEC_TAG() \
   TH_EXEC_TAG()
 
-#define TH_JUMP_TAG(th, st) do { \
-  ruby_longjmp((th)->tag->buf,(st)); \
-} while (0)
+#define TH_JUMP_TAG(th, st) ruby_threadptr_tag_jump(th, st)
 
 #define JUMP_TAG(st) TH_JUMP_TAG(GET_THREAD(), (st))
 
Index: ChangeLog
===================================================================
--- ChangeLog	(revision 43521)
+++ ChangeLog	(revision 43522)
@@ -1,3 +1,9 @@ https://github.com/ruby/ruby/blob/trunk/ChangeLog#L1
+Mon Nov  4 10:08:17 2013  Nobuyoshi Nakada  <nobu@r...>
+
+	* eval_intern.h (TH_EXEC_TAG, TH_JUMP_TAG): get rid of undefined
+	  behavior of setjmp() in rhs of assignment expression.
+	  [ISO/IEC 9899:1999] 7.13.1.1
+
 Sun Nov  3 23:06:51 2013  Tanaka Akira  <akr@f...>
 
 	* sample/test.rb: Make temporary file names unique.

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