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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <mach.h>
# MGC Interface - Simple memory garbage collector interface. Our strategy
# here is simply to store the pointer and its type (so we can dereference to
# a host pointer). As pointers are allocated they are saved here, and when
# freed the pointer value is made negative to indicate it is invalid and
# that slot is available for later reuse.
# When a task completes, we run through the buffer looking for un-freed
# pointers and manually reclaim the space. This is not especially clever but
# we are only used (presumably by developers) when requested so normal use
# of MEMIO should see no added overhead.
#
# mgc_init ()
# mgc_close ()
# mgc_save (ptr, dtype)
# mgc_update (ptr)
# index = mgc_getindex (ptr)
# type = mgc_gettype (ptr)
# mgc_collect ()
define SZ_GC_BUFFER 10240
# A zero-indexed structure saving the (ptr,type) pairs.
define GC_PTR Memi[$1+($2 * 2)]
define GC_TYPE Memi[$1+($2 * 2 + 1)]
# MGC_INIT -- Initialize the MGC interface.
procedure mgc_init ()
include "nmemio.com"
begin
if (mcollect > 0)
call calloc (mgc, SZ_GC_BUFFER, TY_STRUCT)
else
mgc = NULL
end
# MGC_CLOSE -- Close the MGC buffer.
procedure mgc_close ()
include "nmemio.com"
begin
if (mcollect > 0 && mgc != NULL) {
call mfree (mgc, TY_STRUCT)
mgc = NULL
}
end
# MGC_SAVE -- Save a pointer in the GC buffer.
procedure mgc_save (ptr, dtype)
pointer ptr #i pointer to save
int dtype #i pointer type
int i, bmax
include "nmemio.com"
begin
if (mcollect <= 0 || mgc == NULL)
return
bmax = SZ_GC_BUFFER - 1
for (i=0; i < bmax; i=i+1) {
if (GC_PTR(mgc,i) <= 0) {
# Space is re-used if negative, otherwise first free slot.
GC_PTR(mgc,i) = ptr
GC_TYPE(mgc,i) = dtype
if (mdebug > 0) {
call eprintf ("save %d: ptr 0x%x\n")
call pargi (i); call pargi (GC_PTR(mgc,i))
}
return
}
}
# If we get this far we've exhausted the GC buffer. Print a warning
# if reporting and just ignore it since the chances this would be
# a leaked pointer are rather small.
if (mreport > 0)
call eprintf ("Warning: GC buffer overflow\n")
end
# MGC_UPDATE -- Update the status of the pointer in the GC buffer.
procedure mgc_update (ptr)
pointer ptr #i pointer to save
int i, bmax
include "nmemio.com"
begin
if (mgc == NULL || in_task == 0)
return
if (in_task > 0 && mdebug > 0) {
call eprintf ("update 0x%x collect = %d\n")
call pargi (ptr)
call pargi (mcollect)
}
bmax = SZ_GC_BUFFER - 1
do i = 0, bmax {
if (GC_PTR(mgc,i) == ptr) {
if (in_task > 0 && mdebug > 0) {
call eprintf ("update %d: 0x%x %d\n")
call pargi (i); call pargi (GC_PTR(mgc,i)); call pargi (ptr)
}
GC_PTR(mgc,i) = (- ptr)
return
}
if (GC_PTR(mgc,i) == NULL)
return
}
end
# MGC_GETINDEX -- Given a pointer, return its GC index.
int procedure mgc_getindex (ptr)
pointer ptr #i pointer to save
int i, bmax
include "nmemio.com"
begin
if (mcollect <= 0 || mgc == NULL)
return
bmax = SZ_GC_BUFFER - 1
do i = 0, bmax {
if (abs (GC_PTR(mgc,i)) == ptr)
return (i)
if (GC_PTR(mgc,i) == NULL)
return (NULL)
}
return (NULL)
end
# MGC_GETTYPE -- Given a pointer, return its type.
int procedure mgc_gettype (ptr)
pointer ptr #i pointer to save
int i, bmax
include "nmemio.com"
begin
if (mcollect <= 0 || mgc == NULL)
return
bmax = SZ_GC_BUFFER - 1
do i = 0, bmax {
if (abs (GC_PTR(mgc,i)) == ptr)
return (GC_TYPE(mgc,i))
if (GC_PTR(mgc,i) == NULL)
return (NULL)
}
return (NULL)
end
# MGC_COLLECT -- Do the final garbage collection.
procedure mgc_collect ()
int i, bmax, nchars
pointer bp
int sizeof ()
pointer coerce ()
include "nmemio.com"
begin
if (mcollect <= 0 || mgc == NULL)
return
mcollect = -1
bmax = SZ_GC_BUFFER - 1
do i = 0, bmax {
if (GC_PTR(mgc,i) > 0) {
if (mdebug > 0) {
call eprintf ("collect %d: recovering ptr 0x%x\n")
call pargi (i); call pargi (GC_PTR(mgc,i))
}
bp = coerce (GC_PTR(mgc,i), GC_TYPE(mgc,i), TY_INT)
nleaked = nleaked + 1
nchars = Memi[bp - 2] * sizeof (GC_TYPE(mgc,i))
leaked = leaked + (nchars * SZB_CHAR)
call mfree (GC_PTR(mgc,i), GC_TYPE(mgc,i))
} else if (GC_PTR(mgc,i) == NULL)
return
}
end
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