From: Dave Mitchell <davem@fdisolutions.com>
Date: Sat, 14 Aug 2004 22:32:16 +0000 (+0000)
Subject: make pp_goto() cope potential stack reallocation in EXTEND
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=a45cdc79a7c02a2ea3f4f147e8200ca60d683da5;p=p5sagit%2Fp5-mst-13.2.git

make pp_goto() cope potential stack reallocation in EXTEND
The code for goto &foo had local pointers to the stack that
pointed to the wrong place after a realloc.

p4raw-id: //depot/perl@23217
---

diff --git a/pp_ctl.c b/pp_ctl.c
index 4ba1171..f07d716 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -2267,16 +2267,13 @@ PP(pp_goto)
 	    TOPBLOCK(cx);
 	    if (CxREALEVAL(cx))
 		DIE(aTHX_ "Can't goto subroutine from an eval-string");
-	    mark = PL_stack_sp;
 	    if (CxTYPE(cx) == CXt_SUB && cx->blk_sub.hasargs) {
 		/* put @_ back onto stack */
 		AV* av = cx->blk_sub.argarray;
 		
 		items = AvFILLp(av) + 1;
-		PL_stack_sp++;
-		EXTEND(PL_stack_sp, items); /* @_ could have been extended. */
-		Copy(AvARRAY(av), PL_stack_sp, items, SV*);
-		PL_stack_sp += items;
+		EXTEND(SP, items+1); /* @_ could have been extended. */
+		Copy(AvARRAY(av), SP + 1, items, SV*);
 		SvREFCNT_dec(GvAV(PL_defgv));
 		GvAV(PL_defgv) = cx->blk_sub.savearray;
 		/* abandon @_ if it got reified */
@@ -2294,11 +2291,11 @@ PP(pp_goto)
 		AV* av;
 		av = GvAV(PL_defgv);
 		items = AvFILLp(av) + 1;
-		PL_stack_sp++;
-		EXTEND(PL_stack_sp, items); /* @_ could have been extended. */
-		Copy(AvARRAY(av), PL_stack_sp, items, SV*);
-		PL_stack_sp += items;
+		EXTEND(SP, items+1); /* @_ could have been extended. */
+		Copy(AvARRAY(av), SP + 1, items, SV*);
 	    }
+	    mark = SP;
+	    SP += items;
 	    if (CxTYPE(cx) == CXt_SUB &&
 		!(CvDEPTH(cx->blk_sub.cv) = cx->blk_sub.olddepth))
 		SvREFCNT_dec(cx->blk_sub.cv);
@@ -2331,9 +2328,9 @@ PP(pp_goto)
 		    SV **newsp;
 		    I32 gimme;
 
-		    PL_stack_sp--;		/* There is no cv arg. */
 		    /* Push a mark for the start of arglist */
 		    PUSHMARK(mark);
+		    PUTBACK;
 		    (void)(*CvXSUB(cv))(aTHX_ cv);
 		    /* Pop the current context like a decent sub should */
 		    POPBLOCK(cx, PL_curpm);
@@ -2372,7 +2369,6 @@ PP(pp_goto)
 		    GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av);
 		    CX_CURPAD_SAVE(cx->blk_sub);
 		    cx->blk_sub.argarray = av;
-		    ++mark;
 
 		    if (items >= AvMAX(av) + 1) {
 			ary = AvALLOC(av);
@@ -2387,6 +2383,7 @@ PP(pp_goto)
 			    SvPVX(av) = (char*)ary;
 			}
 		    }
+		    ++mark;
 		    Copy(mark,AvARRAY(av),items,SV*);
 		    AvFILLp(av) = items - 1;
 		    assert(!AvREAL(av));
diff --git a/t/op/goto.t b/t/op/goto.t
index b948630..c0936a7 100755
--- a/t/op/goto.t
+++ b/t/op/goto.t
@@ -7,7 +7,7 @@ BEGIN {
     @INC = qw(. ../lib);
 }
 
-print "1..45\n";
+print "1..46\n";
 
 require "test.pl";
 
@@ -393,3 +393,18 @@ moretests:
     }
 }
 
+# deep recursion with gotos eventually caused a stack reallocation
+# which messed up buggy internals that didn't expect the stack to move
+
+sub recurse1 {
+    unshift @_, "x";
+    goto &recurse2;
+}
+sub recurse2 {
+    $x = shift;
+    $_[0] ? +1 + recurse1($_[0] - 1) : 0
+}
+print "not " unless recurse1(500) == 500;
+print "ok 46 - recursive goto &foo\n";
+
+