Author: allison
Date: Sat May 12 12:00:14 2007
New Revision: 18518
Modified:
trunk/config/gen/makefiles/root.in
trunk/include/parrot/pobj.h
trunk/src/gc/dod.c
trunk/src/gc/res_lea.c
trunk/src/string.c
Log:
Refactor src/gc/res_lea.c to allow "Configure.pl --gc=libc" to compile.
Patch from Andy Dougherty, resolves RT #42774.
Modified: trunk/config/gen/makefiles/root.in
==============================================================================
--- trunk/config/gen/makefiles/root.in (original)
+++ trunk/config/gen/makefiles/root.in Sat May 12 12:00:14 2007
@@ -1014,6 +1014,8 @@
$(SRC_DIR)/gc/resources$(O) : $(GENERAL_H_FILES)
+$(SRC_DIR)/gc/res_lea$(O) : $(GENERAL_H_FILES)
+
$(SRC_DIR)/headers$(O) : $(GENERAL_H_FILES)
$(SRC_DIR)/hll$(O) : $(GENERAL_H_FILES)
Modified: trunk/include/parrot/pobj.h
==============================================================================
--- trunk/include/parrot/pobj.h (original)
+++ trunk/include/parrot/pobj.h Sat May 12 12:00:14 2007
@@ -61,6 +61,54 @@
#define PMC_num_val(pmc) (pmc)->obj.u._num_val
#define PMC_str_val(pmc) (pmc)->obj.u._string_val
+/* See src/gc/resources.c. the basic idea is that buffer memory is
+ set up as follows:
+ +-----------------+
+ | ref_count |f | # GC header
+ obj->bufstart -> +-----------------+
+ | data |
+ v v
+
+The actual set-up is more involved because of padding. obj->bufstart must
+be suitably aligned for any UnionVal. (Perhaps it should be a Buffer
+there instead.) The start of the memory region (as returned by malloc()
+is also suitably aligned for any use. If, for example, malloc() returns
+objects aligned on 8-byte boundaries, and obj->bufstart is also aligned
+on 8-byte boundaries, then there should be 4 bytes of padding. It is
+handled differently in the two files resources.c and res_lea.c. (I have
+not yet figured out how the 'possible padding' is handled in resources.c.
+--A.D. 2007-05-11.)
+
+ src/gc/resources.c: src/gc/res_lea.c:
+
+ptr from malloc -> +------------------+ +------------------+
+ | possible padding | | INTVAL ref_count |
+ | INTVAL ref_count | | possible padding |
+obj->bufstart -> +------------------+ +------------------+
+ | data | | data |
+ v v v v
+
+*/
+typedef struct Buffer_alloc_unit {
+ INTVAL ref_count;
+ UnionVal buffer[1]; /* Guarantee it's suitably aligned */
+} Buffer_alloc_unit;
+
+/* Given a pointer to the buffer, find the ref_count and the actual start of
+ the allocated space. Setting ref_count is clunky because we avoid lvalue
+ casts. */
+#ifdef GC_IS_MALLOC /* see src/gc/res_lea.c */
+# define Buffer_alloc_offset (offsetof(Buffer_alloc_unit, buffer))
+# define PObj_bufallocstart(b) ((char *)PObj_bufstart(b) -
Buffer_alloc_offset)
+# define PObj_bufrefcount(b) (((Buffer_alloc_unit
*)PObj_bufallocstart(b))->ref_count)
+# define PObj_bufrefcountptr(b) (&PObj_bufrefcount(b))
+#else /* see src/gc/resources.c */
+# define Buffer_alloc_offset sizeof(INTVAL)
+# define PObj_bufallocstart(b) ((char *)PObj_bufstart(b) -
Buffer_alloc_offset)
+# define PObj_bufrefcount(b) (*(INTVAL *)PObj_bufallocstart(b))
+# define PObj_bufrefcountptr(b) ((INTVAL *)PObj_bufallocstart(b))
+#endif
+
/* BEGIN DEPRECATED BUFFER ACCESSORS */
/* macros for accessing old buffer members
* #define bufstart obj.u._b._bufstart
Modified: trunk/src/gc/dod.c
==============================================================================
--- trunk/src/gc/dod.c (original)
+++ trunk/src/gc/dod.c Sat May 12 12:00:14 2007
@@ -465,7 +465,7 @@
if (PObj_COW_TEST(b) && PObj_bufstart(b) &&
!PObj_external_TEST(b)) {
- INTVAL * const refcount = (INTVAL *) PObj_bufstart(b) - 1;
+ INTVAL * const refcount = PObj_bufrefcountptr(b);
*refcount = 0;
}
}
@@ -503,7 +503,7 @@
PObj_bufstart(b) &&
!PObj_external_TEST(b)) {
- INTVAL * const refcount = (INTVAL *) PObj_bufstart(b) - 1;
+ INTVAL * const refcount = PObj_bufrefcountptr(b);
/* mark users of this bufstart by incrementing refcount */
if (PObj_live_TEST(b))
Modified: trunk/src/gc/res_lea.c
==============================================================================
--- trunk/src/gc/res_lea.c (original)
+++ trunk/src/gc/res_lea.c Sat May 12 12:00:14 2007
@@ -115,57 +115,70 @@
=item C<void
Parrot_reallocate(Interp *interp, Buffer *from, size_t tosize)>
-COWable objects (strings or Buffers) use an INTVAL at C<bufstart> for
-refcounting in DOD. C<bufstart> is incremented by that C<INTVAL>.
+COWable objects (strings or Buffers) use an INTVAL before C<bufstart> for
+refcounting in DOD.
=cut
*/
void
-Parrot_reallocate(Interp *interp, Buffer *from, size_t tosize)
+Parrot_reallocate(Interp *interp, Buffer *buffer, size_t tosize)
{
- Buffer * const buffer = from;
const size_t oldlen = PObj_buflen(buffer);
- void *p;
+ Buffer_alloc_unit *p;
if (!PObj_bufstart(buffer)) {
- p = 1 + (INTVAL *)xcalloc(1, sizeof (INTVAL) + tosize);
+ Parrot_allocate_aligned(interp, buffer, tosize);
+ /* The previous version zeroed the memory here, but I'm not
+ sure why. */
+ memset(PObj_bufstart(buffer), 0, tosize);
}
else {
if (!tosize) { /* realloc(3) does free, if tosize == 0 here */
return; /* do nothing */
}
- p = 1 + (INTVAL *)xrealloc((INTVAL *)PObj_bufstart(buffer) - 1,
- sizeof (INTVAL) + tosize);
+ p = (Buffer_alloc_unit *) xrealloc(PObj_bufallocstart(buffer),
+ Buffer_alloc_offset + tosize);
if (tosize > oldlen)
- memset(p + oldlen, 0, tosize - oldlen);
+ memset((char *)p->buffer + oldlen, 0, tosize - oldlen);
+ PObj_bufstart(buffer) = p->buffer;
+ PObj_buflen(buffer) = tosize;
}
- PObj_bufstart(buffer) = p;
- PObj_buflen(buffer) = tosize;
}
+
/*
=item C<void
Parrot_allocate(Interp *interp, Buffer *buffer, size_t size)>
-Allocates and returns the required memory. C<size> is the number of
-bytes of memory required.
+Allocate buffer memory for the given Buffer pointer. The C<size>
+has to be a multiple of the word size.
+C<PObj_buflen> will be set to exactly the given C<size>.
+See the comments and diagram in resources.c.
+
+This was never called anyway, so it isn't implemented here.
+
+=item C<void
+Parrot_allocate_aligned(Interp *interp, Buffer *buffer, size_t size)>
+
+Like above, except the address of the buffer is guaranteed to be
+suitably aligned for holding anything contained in UnionVal
+(such as FLOATVAL).
=cut
*/
void
-Parrot_allocate(Interp *interp, Buffer *buffer, size_t size)
+Parrot_allocate_aligned(Interp *interp, Buffer *buffer, size_t size)
{
- Buffer * const b = buffer;
- void * const p = xmalloc(sizeof (INTVAL) + size);
-
- *(INTVAL *)p = 0;
- PObj_bufstart(b) = 1 + (INTVAL *)p;
- PObj_buflen(b) = size;
+ Buffer_alloc_unit *p;
+ p = (Buffer_alloc_unit *) xmalloc(Buffer_alloc_offset + size);
+ p->ref_count = 0;
+ PObj_bufstart(buffer) = p->buffer;
+ PObj_buflen(buffer) = size;
}
/*
@@ -183,16 +196,17 @@
void
Parrot_reallocate_string(Interp *interp, STRING *str, size_t tosize)
{
- if (!PObj_bufstart(str))
+ const size_t oldlen = PObj_buflen(str);
+ Buffer_alloc_unit *p;
+
+ if (!PObj_bufstart(str)) {
Parrot_allocate_string(interp, str, tosize);
+ }
else if (tosize) {
- const size_t pad = BUFFER_ALIGNMENT - 1;
- void *p;
- tosize = ((tosize + pad + sizeof (INTVAL)) & ~pad);
- p = xrealloc((char *)((INTVAL*)PObj_bufstart(str) - 1), tosize);
- PObj_bufstart(str) = str->strstart = (char *)p + sizeof (INTVAL);
- /* usable size at bufstart */
- PObj_buflen(str) = tosize - sizeof (INTVAL);
+ p = (Buffer_alloc_unit *) xrealloc(PObj_bufallocstart(str),
+ Buffer_alloc_offset + tosize);
+ PObj_bufstart(str) = str->strstart = (char *) p->buffer;
+ PObj_buflen(str) = tosize;
}
}
@@ -211,14 +225,11 @@
void
Parrot_allocate_string(Interp *interp, STRING *str, size_t size)
{
- void *p;
- const size_t pad = BUFFER_ALIGNMENT - 1;
-
- size = ((size + pad + sizeof (INTVAL)) & ~pad);
- p = xcalloc(1, size);
- *(INTVAL*)p = 0;
- PObj_bufstart(str) = str->strstart = (char *)p + sizeof (INTVAL);
- PObj_buflen(str) = size - sizeof (INTVAL);
+ Buffer_alloc_unit *p;
+ p = (Buffer_alloc_unit *) xcalloc(Buffer_alloc_offset + size, 1);
+ p->ref_count = 0;
+ PObj_bufstart(str) = str->strstart = (char *) p->buffer;
+ PObj_buflen(str) = size;
}
/*
@@ -240,6 +251,21 @@
/*
=item C<void
+Parrot_merge_memory_pools(Interp *dest, Interp *source)>
+
+Does nothing.
+
+=cut
+
+*/
+void
+Parrot_merge_memory_pools(Interp *dest, Interp *source)
+{
+}
+
+/*
+
+=item C<void
Parrot_destroy_memory_pools(Interp *interp)>
Does nothing.
Modified: trunk/src/string.c
==============================================================================
--- trunk/src/string.c (original)
+++ trunk/src/string.c Sat May 12 12:00:14 2007
@@ -206,7 +206,7 @@
/* TODO create string_free API for reusing string headers */
#ifdef GC_IS_MALLOC
if (!PObj_is_cowed_TESTALL(dest) && PObj_bufstart(dest)) {
- mem_sys_free((INTVAL*)PObj_bufstart(dest) - 1);
+ mem_sys_free(PObj_bufallocstart(dest));
}
#endif
dest = Parrot_reuse_COW_reference(interp, src, dest);
