merge revision(s) 54542,54548: [Backport #12082]

	* compile.c (iseq_optimize): disable tail call optimization in
	  rescued, rescue, and ensure blocks.
	  [ruby-core:73871] [Bug #12082]

	* compile.c (new_label_body): initialize bit fields, since
	  compile_data_alloc does not clear the memory.  [Bug #12082]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@54698 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 45 insertions, 2 deletions

diff --git a/compile.c b/compile.c
index e0cc38abd2..001152af70 100644
--- a/compile.c
+++ b/compile.c
@@ -41,6 +41,13 @@ typedef struct iseq_link_anchor {
     LINK_ELEMENT *last;
 } LINK_ANCHOR;
 
+typedef enum {
+    LABEL_RESCUE_NONE,
+    LABEL_RESCUE_BEG,
+    LABEL_RESCUE_END,
+    LABEL_RESCUE_TYPE_MAX
+} LABEL_RESCUE_TYPE;
+
 typedef struct iseq_label_data {
     LINK_ELEMENT link;
     int label_no;
@@ -48,6 +55,7 @@ typedef struct iseq_label_data {
     int sc_state;
     int set;
     int sp;
+    unsigned int rescued: 2;
 } LABEL;
 
 typedef struct iseq_insn_data {
@@ -497,6 +505,9 @@ rb_iseq_compile_node(VALUE self, NODE *node)
 		LABEL *start = iseq->compile_data->start_label = NEW_LABEL(0);
 		LABEL *end = iseq->compile_data->end_label = NEW_LABEL(0);
 
+		start->rescued = LABEL_RESCUE_BEG;
+		end->rescued = LABEL_RESCUE_END;
+
 		ADD_TRACE(ret, FIX2INT(iseq->location.first_lineno), RUBY_EVENT_B_CALL);
 		ADD_LABEL(ret, start);
 		COMPILE(ret, "block body", node->nd_body);
@@ -2038,20 +2049,37 @@ iseq_specialized_instruction(rb_iseq_t *iseq, INSN *iobj)
     return COMPILE_OK;
 }
 
+static inline int
+tailcallable_p(rb_iseq_t *iseq)
+{
+    switch (iseq->type) {
+      case ISEQ_TYPE_RESCUE:
+      case ISEQ_TYPE_ENSURE:
+	/* rescue block can't tail call because of errinfo */
+	return FALSE;
+      default:
+	return TRUE;
+    }
+}
+
 static int
 iseq_optimize(rb_iseq_t *iseq, LINK_ANCHOR *anchor)
 {
     LINK_ELEMENT *list;
     const int do_peepholeopt = iseq->compile_data->option->peephole_optimization;
-    const int do_tailcallopt = iseq->compile_data->option->tailcall_optimization;
+    const int do_tailcallopt = tailcallable_p(iseq) &&
+	iseq->compile_data->option->tailcall_optimization;
     const int do_si = iseq->compile_data->option->specialized_instruction;
     const int do_ou = iseq->compile_data->option->operands_unification;
+    int rescue_level = 0;
+    int tailcallopt = do_tailcallopt;
+
     list = FIRST_ELEMENT(anchor);
 
     while (list) {
 	if (list->type == ISEQ_ELEMENT_INSN) {
 	    if (do_peepholeopt) {
-		iseq_peephole_optimize(iseq, list, do_tailcallopt);
+		iseq_peephole_optimize(iseq, list, tailcallopt);
 	    }
 	    if (do_si) {
 		iseq_specialized_instruction(iseq, (INSN *)list);
@@ -2060,6 +2088,17 @@ iseq_optimize(rb_iseq_t *iseq, LINK_ANCHOR *anchor)
 		insn_operands_unification((INSN *)list);
 	    }
 	}
+	if (list->type == ISEQ_ELEMENT_LABEL) {
+	    switch (((LABEL *)list)->rescued) {
+	      case LABEL_RESCUE_BEG:
+		rescue_level++;
+		tailcallopt = FALSE;
+		break;
+	      case LABEL_RESCUE_END:
+		if (!--rescue_level) tailcallopt = do_tailcallopt;
+		break;
+	    }
+	}
 	list = list->next;
     }
     return COMPILE_OK;
@@ -3108,6 +3147,8 @@ defined_expr(rb_iseq_t *iseq, LINK_ANCHOR *ret,
 						       ("defined guard in "),
 						       iseq->location.label),
 					 ISEQ_TYPE_DEFINED_GUARD, 0);
+	lstart->rescued = LABEL_RESCUE_BEG;
+	lend->rescued = LABEL_RESCUE_END;
 	APPEND_LABEL(ret, lcur, lstart);
 	ADD_LABEL(ret, lend);
 	ADD_CATCH_ENTRY(CATCH_TYPE_RESCUE, lstart, lend, rescue, lfinish[1]);
@@ -3878,6 +3919,8 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE * node, int poped)
 	    rb_str_concat(rb_str_new2("rescue in "), iseq->location.label),
 	    ISEQ_TYPE_RESCUE, line);
 
+	lstart->rescued = LABEL_RESCUE_BEG;
+	lend->rescued = LABEL_RESCUE_END;
 	ADD_LABEL(ret, lstart);
 	COMPILE(ret, "rescue head", node->nd_head);
 	ADD_LABEL(ret, lend);