# New Ticket Created by Bram Geron
# Please include the string: [perl #41583]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=41583 >
---
osname= linux
osvers= 2.6.18.3
arch= i486-linux-gnu-thread-multi
cc= cc
---
Flags:
category=core
severity=medium
ack=no
---
Tail calls from within v-table methods are broken, the tail-called sub
(or method) will not return correct values.
When method A tailcalls sub B, B's set_returns stores its opcode
number (and with it, which registers should be returned), but the
low-level vtable code gets the registers from A's context.
(Runops_args stores a pointer to A's context just before it is called,
wrongly assuming A has the final set_returns. Runops_args returns the
context to a function that then does return value passing on it.)
Maybe the solution is to store the current context in a new field in
the interp structure; I don't know, I'm rather bad at C.
Example:
This should print 2, but it prints 13.
-----
.sub main :main
$P1 = newclass "Foo"
$P2 = new "Foo"
## Should return 2, but doesn't.
$I1 = elements $P2
$S1 = $I1
say $S1
.end
.namespace ["Foo"]
.sub elements :method :vtable
I0 = 13
I1 = 2
.return identity(I1)
.end
.sub identity
.param int arg
## arg is I0, taken from the elements context (which is set
## to 13). If we put "I0 = 14" here and don't optimize, we
## return 2. (elements's context's I1)
.return (arg)
.end
-----
This happens in svn head.
Regards,
Bram Geron.
---
Summary of my parrot 0.4.8 (r16890) configuration:
configdate='Sat Feb 10 16:50:38 2007'
Platform:
osname=linux, archname=i486-linux-gnu-thread-multi
jitcapable=1, jitarchname=i386-linux,
jitosname=LINUX, jitcpuarch=i386
execcapable=1
perl=/usr/bin/perl
Compiler:
cc='cc', ccflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS
-DDEBIAN -pipe -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -I /usr/include',
Linker and Libraries:
ld='cc', ldflags=' -L/usr/local/lib',
cc_ldflags='',
libs='-ldl -lm -lpthread -lcrypt -lrt -lgmp -lreadline -lncurses'
Dynamic Linking:
share_ext='.so', ld_share_flags='-shared -L/usr/local/lib -fPIC',
load_ext='.so', ld_load_flags='-shared -L/usr/local/lib -fPIC'
Types:
iv=long, intvalsize=4, intsize=4, opcode_t=long, opcode_t_size=4,
ptrsize=4, ptr_alignment=1 byteorder=1234,
nv=double, numvalsize=8, doublesize=8
---
Environment:
HOME LANG LANGUAGE LD_LIBRARY_PATH LOGDIR PATH SHELL
