gnupic: gpasm `extern' vs `global' (new feature patch)
Subject:
gpasm `extern' vs `global' (new feature patch)
From:
Ian Jackson ####@####.####
Date:
20 Apr 2005 19:01:39 +0100
Message-Id: <16998.39166.693870.296718@davenant.relativity.greenend.org.uk>
I found it inconvenient that when defining a global symbol (one with
`external linkage' in C parlance, although there is of course no C
here) in gpasm I have to say `global', but when I'm referring to it I
have to say `extern'. That means I can't have one include file with a
list of all of the global symbols.
So, I wrote the patch below which is supposed to allow the use of
`extern' even for symbols defined in the same file, at least for
labels. (You have to say `extern' before the label.) When the
definition is encountered the symbol is converted from extern to
global. This appears to work for me.
I'd be grateful if you'd let me know what you think of it, and I would
be very happy if it were included in future gputils versions.
The patch was made against Debian's gputils 0.13.1-1. This will be
very similar to upstream 0.13.1. Note though that due to a bug in
0.13.1-1 I'm actually using 0.12.4-1 to which the patch also applies
cleanly.
One oddity was that I had to use fprintf(stderr,...) for my
diagnostic. It's not clear that a diagnostic is warranted - I just
wanted to know that my code was working. It should probably be taken
out at some point. I tried using gpmessage but gpmessage only works
on pass 2 and this message about promoting an `extern' to a `global'
is only issued during pass 1 because the promotion happens only once,
the first time the label definition is processed.
Thanks,
Ian.
diff --exclude Makefile --exclude config.log --exclude config.status -ru orig/gputils-0.13.1/gpasm/coff.c gputils-0.13.1/gpasm/coff.c
--- orig/gputils-0.13.1/gpasm/coff.c Mon Jan 3 22:21:04 2005
+++ gputils-0.13.1/gpasm/coff.c Wed Apr 20 17:39:57 2005
@@ -447,7 +447,7 @@
if ((new->type != class) ||
(new->section_number != section_number)) {
snprintf(message, sizeof(message),
- "Duplicate label or redefining symbol that cannot be redefined. (%s)",
+ "Duplicate extern label or redefining symbol that cannot be redefined. (%s)",
name);
gperror(GPE_UNKNOWN, message);
}
@@ -455,7 +455,7 @@
if ((new != NULL) && (type != gvt_extern) && (type != gvt_debug)) {
snprintf(message, sizeof(message),
- "Duplicate label or redefining symbol that cannot be redefined. (%s)",
+ "Duplicate non-extern label or redefining symbol that cannot be redefined. (%s)",
name);
gperror(GPE_DUPLAB, message);
} else {
Only in gputils-0.13.1/gpasm: coff.c~
Only in gputils-0.13.1/gpasm: gperror.h~
diff --exclude Makefile --exclude config.log --exclude config.status -ru orig/gputils-0.13.1/gpasm/util.c gputils-0.13.1/gpasm/util.c
--- orig/gputils-0.13.1/gpasm/util.c Mon Jan 3 22:21:19 2005
+++ gputils-0.13.1/gpasm/util.c Wed Apr 20 18:14:00 2005
@@ -160,6 +160,7 @@
if (sym == NULL)
sym = add_symbol(state.stGlobal, name);
var = get_symbol_annotation(sym);
+
if (var == NULL) {
/* new symbol */
var = malloc(sizeof(*var));
@@ -184,6 +185,11 @@
*/
var->value = value;
+ } else if (type == gvt_extern && var->type == gvt_global) {
+ /* Ignore `extern' directies for things that we have actually
+ * seen defined and which therefore became global.
+ */
+
} else if (state.pass == 2) {
char *coff_name;
@@ -201,6 +207,17 @@
if (coff_name != NULL)
free(coff_name);
+
+ } else if (type == gvt_address && var->type == gvt_extern) {
+ char message[BUFSIZ];
+
+ fprintf(stderr,
+ "Symbol \"%s\" declared extern but defined as address by"
+ " use as label, making global\n", name);
+
+ var->type = gvt_global;
+ var->value = value;
+
}
/* increment the index into the coff symbol table for the relocations */
Only in gputils-0.13.1/gpasm: util.c~
