I've been writing a Lisp implementation on top of Parrot for the last several months (and I'm just about at the point where I'm ready to unleash it upon the world). I seem to have run up against some issues which *appear* to be related to the garbage collector collecting objects that aren't ready to be collected yet. (I say "appear" because I'm unsure as to how to check when an object is being collected and the memory returned to the system - for all I know this could be entirely my fault.)
I've included a much pared down example IMC file which on an x86 Linux machine will produce a segmentation fault and on a Mac OS X 10.3 machine produces a bus error. Running with the garbage collection disabled (ie. with the -G flag) does not produce these errors.
If anyone could point me towards what is going wrong, I would MOST appreciate it - it's been driving me nuts. (I've been following Parrot internals only superficially for the past little while so I'm entirely unfamiliar with the garbage collection system.) I have only a vague
inclination that it has to do somehow with the Hash class (based on how various bugs manifest themselves in my program).
The Parrot version is the latest CVS checkout as of 10 minutes ago.
Regards,
Cory
.macro PACKAGE (P,N) .P = new "LispPackage" .P._set_name_as_string(.N) .endm
.macro STRING (R,S)
.R = new "LispString"
.R = .S
.endm
.macro SYMBOL (R,N)
.R = new "LispSymbol"
.R._set_name_as_string(.N)
.endm
.sub _main @MAIN
.local pmc package1
.local pmc package2
.local pmc package3
.local pmc symbol
.local int count
_init_types()
.PACKAGE(package1, "COMMON-LISP")
symbol = package1._intern_symbol("T")
count = 0
LOOP:
print count
print ": "
print "looking up symbol: T\n"
symbol = package1._lookup_symbol("T")
.PACKAGE(package3, "SYSTEM")
package3._import_symbol(symbol)
symbol = package1._lookup_symbol("T")
package2 = symbol._get_package()
inc count
goto LOOP
end
.end
.sub _init_types
.local pmc class
# Create the LispPackage class
newclass class, "LispPackage"
addattribute class, "internal"
addattribute class, "name"
# Create the LispString class
subclass class, "String", "LispString"
# Create the LispSymbol class
newclass class, "LispSymbol"
addattribute class, "function"
addattribute class, "name"
addattribute class, "package"
.end
.namespace ["LispPackage"]
.sub __init method
.local pmc value
value = new Hash
setattribute self, "LispPackage\0internal", value
.end
.sub _lookup_symbol method
.param string name
.local string type
.local pmc symbol
.local pmc hash
getattribute hash, self, "LispPackage\0internal"
symbol = hash[name]
typeof type, symbol
if type == "None" goto SYMBOL_NOT_FOUND
goto DONE
SYMBOL_NOT_FOUND:
null symbol
goto DONE
DONE:
.return(symbol)
.end
.sub _import_symbol method
.param pmc symbol
.local string symname
.local pmc hash
symname = symbol._get_name_as_string()
getattribute hash, self, "LispPackage\0internal"
hash[symname] = symbol
.return(symbol)
.end
.sub _intern_symbol method
.param string name
.local string type
.local pmc symbol
.local pmc status
.local pmc hash
getattribute hash, self, "LispPackage\0internal"
symbol = hash[name]
typeof type, symbol
if type != "None" goto DONE
.SYMBOL(symbol, name)
hash[name] = symbol
symbol._set_package(self)
goto DONE
DONE:
.return(symbol)
.end
.sub _get_name_as_string method
.local pmc name
.local string retv
getattribute name, self, "LispPackage\0name"
retv = name
.return(retv)
.end
.sub _set_name_as_string method
.param string name
.local pmc retv
.STRING(retv, name)
setattribute self, "LispPackage\0name", retv
.return(retv)
.end
.sub __get_string method
.local pmc name
.local pmc tmps
.local pmc retv
getattribute name, self, "LispPackage\0name"
retv = new String
tmps = new String
tmps = "#<PACKAGE "
concat retv, tmps, name
tmps = ">"
concat retv, retv, tmps
.pcc_begin_return
.return retv
.pcc_end_return
.end
.namespace ["LispSymbol"]
.sub _get_name_as_string method
.local pmc name
.local string retv
getattribute name, self, "LispSymbol\0name"
retv = name
.return(retv)
.end
.sub _set_name_as_string method
.param string name
.local pmc retv
.STRING(retv, name)
setattribute self, "LispSymbol\0name", retv
.return(retv)
.end
.sub _get_package method
.local pmc retv
getattribute retv, self, "LispSymbol\0package"
.return(retv)
.end
.sub _set_package method
.param pmc package
setattribute self, "LispSymbol\0package", package
.return(package)
.end
.sub __get_string method
.local pmc name
getattribute name, self, "LispSymbol\0name"
.pcc_begin_return
.return name
.pcc_end_return
.end
.namespace [""]
