move the SETJMP exception-handing definitions from scope.h to cop.h

so that a JMPENV* entry can be added to struct block_eval

p4raw-id: //depot/perl@24361

1 files changed, 120 insertions, 0 deletions

diff --git a/cop.h b/cop.h
index bddc328d13..172c265a60 100644
--- a/cop.h
+++ b/cop.h
@@ -13,6 +13,126 @@
  * and thus can be used to determine our current state.
  */
 
+/* A jmpenv packages the state required to perform a proper non-local jump.
+ * Note that there is a start_env initialized when perl starts, and top_env
+ * points to this initially, so top_env should always be non-null.
+ *
+ * Existence of a non-null top_env->je_prev implies it is valid to call
+ * longjmp() at that runlevel (we make sure start_env.je_prev is always
+ * null to ensure this).
+ *
+ * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
+ * establish a local jmpenv to handle exception traps.  Care must be taken
+ * to restore the previous value of je_mustcatch before exiting the
+ * stack frame iff JMPENV_PUSH was not called in that stack frame.
+ * GSAR 97-03-27
+ */
+
+struct jmpenv {
+    struct jmpenv *	je_prev;
+    Sigjmp_buf		je_buf;		/* only for use if !je_throw */
+    int			je_ret;		/* last exception thrown */
+    bool		je_mustcatch;	/* need to call longjmp()? */
+};
+
+typedef struct jmpenv JMPENV;
+
+#ifdef OP_IN_REGISTER
+#define OP_REG_TO_MEM	PL_opsave = op
+#define OP_MEM_TO_REG	op = PL_opsave
+#else
+#define OP_REG_TO_MEM	NOOP
+#define OP_MEM_TO_REG	NOOP
+#endif
+
+/*
+ * How to build the first jmpenv.
+ *
+ * top_env needs to be non-zero. It points to an area
+ * in which longjmp() stuff is stored, as C callstack
+ * info there at least is thread specific this has to
+ * be per-thread. Otherwise a 'die' in a thread gives
+ * that thread the C stack of last thread to do an eval {}!
+ */
+
+#define JMPENV_BOOTSTRAP \
+    STMT_START {				\
+	Zero(&PL_start_env, 1, JMPENV);		\
+	PL_start_env.je_ret = -1;		\
+	PL_start_env.je_mustcatch = TRUE;	\
+	PL_top_env = &PL_start_env;		\
+    } STMT_END
+
+/*
+ *   PERL_FLEXIBLE_EXCEPTIONS
+ * 
+ * All the flexible exceptions code has been removed.
+ * See the following threads for details:
+ *
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
+ * 
+ * Joshua's original patches (which weren't applied) and discussion:
+ * 
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
+ * 
+ * Chip's reworked patch and discussion:
+ * 
+ *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
+ * 
+ * The flaw in these patches (which went unnoticed at the time) was
+ * that they moved some code that could potentially die() out of the
+ * region protected by the setjmp()s.  This caused exceptions within
+ * END blocks and such to not be handled by the correct setjmp().
+ * 
+ * The original patches that introduces flexible exceptions were:
+ *
+ *   http://public.activestate.com/cgi-bin/perlbrowse?patch=3386
+ *   http://public.activestate.com/cgi-bin/perlbrowse?patch=5162
+ */
+
+#define dJMPENV		JMPENV cur_env
+
+#define JMPENV_PUSH(v) \
+    STMT_START {							\
+	DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",	\
+			 &cur_env, PL_top_env));			\
+	cur_env.je_prev = PL_top_env;					\
+	OP_REG_TO_MEM;							\
+	cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);		\
+	OP_MEM_TO_REG;							\
+	PL_top_env = &cur_env;						\
+	cur_env.je_mustcatch = FALSE;					\
+	(v) = cur_env.je_ret;						\
+    } STMT_END
+
+#define JMPENV_POP \
+    STMT_START {							\
+	DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p\n",	\
+			 PL_top_env, cur_env.je_prev));			\
+	PL_top_env = cur_env.je_prev;					\
+    } STMT_END
+
+#define JMPENV_JUMP(v) \
+    STMT_START {						\
+	OP_REG_TO_MEM;						\
+	if (PL_top_env->je_prev)				\
+	    PerlProc_longjmp(PL_top_env->je_buf, (v));		\
+	if ((v) == 2)						\
+	    PerlProc_exit(STATUS_NATIVE_EXPORT);		\
+	PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");	\
+	PerlProc_exit(1);					\
+    } STMT_END
+
+#define CATCH_GET		(PL_top_env->je_mustcatch)
+#define CATCH_SET(v)		(PL_top_env->je_mustcatch = (v))
+
+
+
 struct cop {
     BASEOP
     char *	cop_label;	/* label for this construct */