[nasm:debug-macros] debug: don't call dfmt->linenum without a filename

[nasm-bot for H. Peter Anvin (Intel)]

Commit-ID:  0d4ce8d7395e2a0850d21248b31f248834ad701a
Gitweb:     http://repo.or.cz/w/nasm.git?a=commitdiff;h=0d4ce8d7395e2a0850d21248b31f248834ad701a
Author:     H. Peter Anvin (Intel) <hpa at zytor.com>
AuthorDate: Thu, 9 Jul 2020 21:10:42 -0700
Committer:  H. Peter Anvin (Intel) <hpa at zytor.com>
CommitDate: Thu, 9 Jul 2020 21:10:42 -0700

debug: don't call dfmt->linenum without a filename

With -Lb, it is possible that we don't have a filename for the current
code expansion. In that case, suppress calling dfmt->linenum as some
debug backends *really* aren't equipped to handle that case.

Signed-off-by: H. Peter Anvin (Intel) <hpa at zytor.com>


---
 asm/assemble.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/asm/assemble.c b/asm/assemble.c
index 270262ae..2c47ba58 100644
--- a/asm/assemble.c
+++ b/asm/assemble.c
@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------- *
  *
- *   Copyright 1996-2019 The NASM Authors - All Rights Reserved
+ *   Copyright 1996-2020 The NASM Authors - All Rights Reserved
  *   See the file AUTHORS included with the NASM distribution for
  *   the specific copyright holders.
  *
@@ -401,11 +401,14 @@ static void out(struct out_data *data)
 
     /*
      * If the source location or output segment has changed,
-     * let the debug backend know.
+     * let the debug backend know. Some backends really don't
+     * like being given a NULL filename as can happen if we
+     * use -Lb and expand a macro, so filter out that case.
      */
     data->where = src_where();
-    if (!src_location_same(data->where, dbg.where) |
-        (data->segment != dbg.segment)) {
+    if (data->where.filename &&
+        (!src_location_same(data->where, dbg.where) |
+         (data->segment != dbg.segment))) {
         dbg.where   = data->where;
         dbg.segment = data->segment;
         dfmt->linenum(dbg.where.filename, dbg.where.lineno, data->segment);