# New Ticket Created by Bram Geron
# Please include the string: [perl #46593]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=46593 >
I think attached patch clarifies parameter passing a little.
Non-comment changes:
* enum call_state_mode becomes typedef'd call_state_mode
* call_state_item.mode becomes type call_state_mode instead of int
* call_state_item.sig becomes type Call_bits_enum_t instead of INTVAL
include/parrot/inter_call.h | 68
+++++++++++++++++++++++++++-----------------
src/inter_call.c | 13 ++++++--
2 files changed, 52 insertions(+), 29 deletions(-)
Cheers,
--
Bram Geron | GPG 0xE7B9E65E
diff --git a/include/parrot/inter_call.h b/include/parrot/inter_call.h
index f08e225..a16ea02 100644
--- a/include/parrot/inter_call.h
+++ b/include/parrot/inter_call.h
@@ -16,38 +16,54 @@
#ifndef PARROT_INTER_CALL_H_GUARD
#define PARROT_INTER_CALL_H_GUARD
-enum call_state_mode {
- /* arg processing states
- * <src>_<dest> sd nibbles */
-
- CALL_STATE_SIG = 0x100, /* runops, nci */
- CALL_STATE_OP = 0x200, /* get_, set_ ops */
- CALL_S_D_MASK = 0x300, /* src/dest mask */
-
- CALL_STATE_FLATTEN = 0x400 /* flatten src */
-
-};
+typedef enum call_state_mode {
+ /* argument fetching/putting modes */
+ CALL_STATE_SIG = 0x100, /* runops, nci. In case we're interfacing with
+ C and va_lists. */
+ CALL_STATE_OP = 0x200, /* get_, set_ ops. In case we're interfacing
+ with Parrot code and get the signature from
+ call_state_item.u.op. */
+ CALL_S_D_MASK = 0x300, /* src/dest mask */
+
+ /* whether we are busy in a :flat argument */
+ CALL_STATE_FLATTEN = 0x400
+} call_state_mode;
typedef struct call_state_item {
- int mode; /* from_sig, from_set_ops, flatten ...*/
+ /* We have one call_state_item for both the caller (source,
+ arguments/returns) and the callee (destination, parameters/results). */
+ call_state_mode mode; /* this specifies
+ - where we get our arguments from / where we put
+ our parameters (from C code or from set_*,get_*)
+ - if we're in the middle of a :flat */
+
union {
- struct {
- void *ap; /* a ptr to va_list */
- const char *sig;
+ struct { /* In case the caller (or callee? FIXME)
+ is C code: */
+ void *ap; /* a ptr to va_list */
+ const char *sig; /* a C string describing the type of each
argument */
} sig;
- struct {
- opcode_t *pc;
- PMC *signature;
+
+ struct { /* In case the caller/callee was Parrot code: */
+ opcode_t *pc; /* array of 'indexes' for each argument:
+ - in case it's about a constant, the constant
number
+ - in case it's about a register, the register
number */
+ PMC *signature; /* a PMC array holding a Call_bits_enum_t
+ signature for each argument */
} op;
} u;
- parrot_context_t *ctx;
- INTVAL used;
- INTVAL i;
- INTVAL n;
- INTVAL sig;
- PMC *slurp;
- INTVAL slurp_i;
- INTVAL slurp_n;
+
+ parrot_context_t *ctx; /* the context where we get the args from / put the
params in */
+ INTVAL used; /* src: whether this argument has been consumed already
(or: whether the previous arg has already been consumed?) */
+ INTVAL i; /* number of args/params already consumed / filled in */
+ INTVAL n; /* number of args/params we are supposed to match. may
include :slurpys and :flats */
+ Call_bits_enum_t sig; /* type of current arg/param (counting from 1, the
i'th) */
+
+ /* We might encounter a :flat. */
+ /* FIXME bgeron: is this used for :slurpys? I can't find a reference in
slurpy-filling code. */
+ PMC *slurp; /* PMC in which to put the args we slurp up / from where
to flatten */
+ INTVAL slurp_i; /* index of :flat/:slurpy arg/param we are trying to match
*/
+ INTVAL slurp_n; /* number of :flat/:slurpy args/params we are supposed to
match */
} call_state_item;
typedef struct call_state {
diff --git a/src/inter_call.c b/src/inter_call.c
index 9c522d8..0e9920e 100644
--- a/src/inter_call.c
+++ b/src/inter_call.c
@@ -329,7 +329,9 @@ start_flatten(PARROT_INTERP, NOTNULL(call_state *st),
NOTNULL(PMC *p_arg))
st->n_actual_args += st->src.slurp_n - 1;
}
-
+/* Calculate what type of argument/parameter we get next
+ * (the index has already been increased by now)
+ */
static void
next_arg_sig(NOTNULL(call_state_item *sti))
{
@@ -357,6 +359,8 @@ next_arg_sig(NOTNULL(call_state_item *sti))
}
}
+/* Fetch an argument from C code
+ */
static int
fetch_arg_sig(PARROT_INTERP, NOTNULL(call_state *st))
{
@@ -401,7 +405,8 @@ fetch_arg_sig(PARROT_INTERP, NOTNULL(call_state *st))
return 1;
}
-
+/* Fetch an argument from a Parrot_Context
+ */
static int
fetch_arg_op(PARROT_INTERP, NOTNULL(call_state *st))
{
@@ -448,6 +453,8 @@ fetch_arg_op(PARROT_INTERP, NOTNULL(call_state *st))
return 1;
}
+/* Fetch a new argument.
+ */
PARROT_API
int
Parrot_fetch_arg(PARROT_INTERP, NOTNULL(call_state *st))
@@ -460,7 +467,7 @@ Parrot_fetch_arg(PARROT_INTERP, NOTNULL(call_state *st))
next_arg_sig(&st->src);
- /* check if we're at a :flat argument */
+ /* check if we're supposed to continue a :flat argument */
if (st->src.mode & CALL_STATE_FLATTEN) {
PMC *elem;
PARROT_ASSERT(st->src.slurp_i < st->src.slurp_n);
