[nasm:master] preproc: Fix in accessing the definition structure of a single-line macro

[nasm-bot f. C. S. B. <cha...@in...>]

Commit-ID:  c52aff4cc8680e404cce1cc2a183b7015f07be08
Gitweb:     http://repo.or.cz/w/nasm.git?a=commitdiff;h=c52aff4cc8680e404cce1cc2a183b7015f07be08
Author:     Chang S. Bae <cha...@in...>
AuthorDate: Mon, 20 Apr 2020 21:43:44 +0000
Committer:  Chang S. Bae <cha...@in...>
CommitDate: Tue, 21 Apr 2020 21:41:33 +0000

preproc: Fix in accessing the definition structure of a single-line macro

Determining whether we should warn on defining a single-line macro, with a
name and a certain number of parameters, call a helper function,
smacro_defined(). It does not always return the address of the definition
structure.

Fix the code to be cautiously accessing the definition structure.

Fixes: e91f5cc1322e ("preproc: fix %undef of macro aliases, and add
%ifdefalias")

Reported-by: Dale Curtis <dal...@ch...>
Link: https://bugzilla.nasm.us/show_bug.cgi?id=3392659
Signed-off-by: Chang S. Bae <cha...@in...>


---
 asm/preproc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/asm/preproc.c b/asm/preproc.c
index fae3b868..9ab05765 100644
--- a/asm/preproc.c
+++ b/asm/preproc.c
@@ -2448,7 +2448,7 @@ static enum cond_state if_condition(Token * tline, enum preproc_token ct)
 
             mname = tok_text(tline);
             ctx = get_ctx(mname, &mname);
-            if (smacro_defined(ctx, mname, 0, &smac, true, alias)
+            if (smacro_defined(ctx, mname, 0, &smac, true, alias) && smac
                 && smac->alias == alias) {
                 j = true;
                 break;