Hi,
I ran tests for automake 1.16.5 on OpenIndiana and following 4 tests
failed:
FAIL: t/yacc-cxx.sh
FAIL: t/yacc-clean-cxx.sh
FAIL: t/yacc-d-cxx.sh
FAIL: t/yacc-mix-c-cxx.sh
The cause for the failure is this:
parse1.yy:30:7: error: conflicting declaration of 'void yyerror(const char*)'
with 'C' linkage
parse1.yy:7:6: note: previous declaration with 'C++' linkage
7 | void yyerror (const char *s) {}
| ^~~~~~~
parse1.yy:34:6: error: conflicting declaration of 'int yylex()' with 'C' linkage
parse1.yy:6:5: note: previous declaration with 'C++' linkage
6 | int yylex (void) { return std::getchar (); }
| ^~~~~
For testing there is the default system yacc used. It is the illumos
yacc as inherited from Solaris with some changes[1]. The generated code
that causes the failure is this:
24 #if defined(__cplusplus) || defined(__STDC__)
25
26 #if defined(__cplusplus)
27 extern "C" {
28 #endif
29 #ifndef yyerror
30 #if defined(__cplusplus)
31 void yyerror(YYCONST char *);
32 #endif
33 #endif
34 #ifndef yylex
35 int yylex(void);
36 #endif
37 int yyparse(void);
38 #if defined(__cplusplus)
39 }
40 #endif
41
42 #endif
The issue is apparent. The yacc generated code create both yyerror()
and yylex() with the C linkage, but testing expects C++ linkage. This
is exactly what the compiler error says.
All of this is obvious. So where is the bug and what should be fixed?
There are few possible views:
1. yacc is buggy and should not force C linkage for C++ source. This is
grey area because POSIX says nothing about linkage or C++[2].
2. The tests' expectations about yacc behavior re C++ are too strong.
This seems to be true for illumos yacc. Other yacc implementations, for
example GNU bison, does better job and do not force C linkage for
affected functions.
My proposal to solve the issue is to change affected tests to require
bison instead of yacc. Please see attachment.
Thank you.
[1] for example this: https://www.illumos.org/issues/16136
[2] https://pubs.opengroup.org/onlinepubs/9699919799/utilities/yacc.html
--
+-------------------------------------------+
| Marcel Telka e-mail: [email protected] |
| homepage: http://telka.sk/ |
+-------------------------------------------+
--- automake-1.16.5/t/yacc-cxx.sh.orig
+++ automake-1.16.5/t/yacc-cxx.sh
@@ -18,7 +18,7 @@
# headers are not involved).
# Keep in sync with sister test 'yacc-basic.sh'.
-required='c++ yacc'
+required='c++ bison'
. test-init.sh
cat >> configure.ac << 'END'
--- automake-1.16.5/t/yacc-clean-cxx.sh.orig
+++ automake-1.16.5/t/yacc-clean-cxx.sh
@@ -20,7 +20,7 @@
# "make maintainer-clean".
# See also sister test 'yacc-clean.sh'.
-required='c++ yacc'
+required='c++ bison'
. test-init.sh
cat >> configure.ac << 'END'
--- automake-1.16.5/t/yacc-d-cxx.sh.orig
+++ automake-1.16.5/t/yacc-d-cxx.sh
@@ -18,7 +18,7 @@
# (i.e., '-d' in *YFLAGS).
# Keep in sync with sister test 'yacc-d-basic.sh'.
-required='c++ yacc'
+required='c++ bison'
. test-init.sh
write_parse ()
--- automake-1.16.5/t/yacc-mix-c-cxx.sh.orig
+++ automake-1.16.5/t/yacc-mix-c-cxx.sh
@@ -17,7 +17,7 @@
# Check that many different Yacc parsers (both C and C++) can co-exists
# in the same directory.
-required='cc c++ yacc'
+required='cc c++ bison'
. test-init.sh
cat >> configure.ac << 'END'
