From 2f05bb60997488703c97838ee2c50059f73c3892 Mon Sep 17 00:00:00 2001
From: Peter Johnson <peter@tortall.net>
Date: Sun, 25 Sep 2005 01:01:02 +0000
Subject: [PATCH] * symrec.h (yasm_symtab_parser_finalize): Add function to
 declare all undefined symbols extern if unused rather than causing undef
 errors. * symrec.c (yasm_symtab_parser_finalize): Implement.
 (symtab_finalize_info): New (more data to pass to
 (symtab_parser_finalize_checksym): Update finalize helper.

* yasm.c (main): Update call to yasm_symtab_parser_finalize().

svn path=/trunk/yasm/; revision=1232
---
 frontends/yasm/yasm.c |  2 +-
 libyasm/symrec.c      | 30 ++++++++++++++++++++++++------
 libyasm/symrec.h      |  7 ++++++-
 3 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/frontends/yasm/yasm.c b/frontends/yasm/yasm.c
index b338f0ce..10e39c8f 100644
--- a/frontends/yasm/yasm.c
+++ b/frontends/yasm/yasm.c
@@ -611,7 +611,7 @@ main(int argc, char *argv[])
 	fclose(in);
 
     /* Check for undefined symbols */
-    yasm_symtab_parser_finalize(yasm_object_get_symtab(object));
+    yasm_symtab_parser_finalize(yasm_object_get_symtab(object), 0, NULL);
 
     if (yasm_get_num_errors(warning_error) > 0) {
 	yasm_errwarn_output_all(yasm_object_get_linemap(object), warning_error,
diff --git a/libyasm/symrec.c b/libyasm/symrec.c
index fac2fbd3..2fab0e82 100644
--- a/libyasm/symrec.c
+++ b/libyasm/symrec.c
@@ -282,10 +282,17 @@ yasm_symrec_declare(yasm_symrec *rec, yasm_sym_vis vis, unsigned long line)
 	    rec->name, rec->line);
 }
 
+typedef struct symtab_finalize_info {
+    unsigned long firstundef_line;
+    int undef_extern;
+    /*@null@*/ yasm_objfmt *objfmt;
+} symtab_finalize_info;
+
 static int
 symtab_parser_finalize_checksym(yasm_symrec *sym, /*@null@*/ void *d)
 {
     unsigned long *firstundef_line = d;
+    symtab_finalize_info *info = (symtab_finalize_info *)d;
     /* error if a symbol is used but never defined or extern/common declared */
     if ((sym->status & SYM_USED) && !(sym->status & SYM_DEFINED) &&
 	!(sym->visibility & (YASM_SYM_EXTERN | YASM_SYM_COMMON))) {
@@ -293,19 +300,30 @@ symtab_parser_finalize_checksym(yasm_symrec *sym, /*@null@*/ void *d)
 		    sym->name);
 	if (sym->line < *firstundef_line)
 	    *firstundef_line = sym->line;
+	if (info->undef_extern && info->objfmt)
+	    yasm_objfmt_extern_declare(info->objfmt, sym->name, NULL, 1);
+	else {
+	    yasm__error(sym->line, N_("undefined symbol `%s' (first use)"),
+			sym->name);
+	    if (sym->line < info->firstundef_line)
+		info->firstundef_line = sym->line;
+	}
     }
 
     return 1;
 }
 
 void
-yasm_symtab_parser_finalize(yasm_symtab *symtab)
+yasm_symtab_parser_finalize(yasm_symtab *symtab, int undef_extern,
+			    yasm_objfmt *objfmt)
 {
-    unsigned long firstundef_line = ULONG_MAX;
-    yasm_symtab_traverse(symtab, &firstundef_line,
-			 symtab_parser_finalize_checksym);
-    if (firstundef_line < ULONG_MAX)
-	yasm__error(firstundef_line,
+    symtab_finalize_info info;
+    info.firstundef_line = ULONG_MAX;
+    info.undef_extern = undef_extern;
+    info.objfmt = objfmt;
+    yasm_symtab_traverse(symtab, &info, symtab_parser_finalize_checksym);
+    if (info.firstundef_line < ULONG_MAX)
+	yasm__error(info.firstundef_line,
 		    N_(" (Each undefined symbol is reported only once.)"));
 }
 
diff --git a/libyasm/symrec.h b/libyasm/symrec.h
index 64b1ef04..4d4a879d 100644
--- a/libyasm/symrec.h
+++ b/libyasm/symrec.h
@@ -144,8 +144,13 @@ int /*@alt void@*/ yasm_symtab_traverse
 
 /** Finalize symbol table after parsing stage.  Checks for symbols that are
  * used but never defined or declared #YASM_SYM_EXTERN or #YASM_SYM_COMMON.
+ * \param symtab	symbol table
+ * \param undef_extern	if nonzero, all undef syms should be declared extern
+ * \param objfmt	object format to notify about new extern decls
+ *			(may be NULL if undef_extern is 0)
  */
-void yasm_symtab_parser_finalize(yasm_symtab *symtab);
+void yasm_symtab_parser_finalize(yasm_symtab *symtab, int undef_extern,
+				 /*@null@*/ yasm_objfmt *objfmt);
 
 /** Print the symbol table.  For debugging purposes.
  * \param symtab	symbol table
-- 
2.40.0