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e57f7fa070
When building with clang 15 on Ubuntu 20.04, I get:
CXX cp-name-parser.o
cp-name-parser.c.tmp:1777:9: error: variable 'cpnameyynerrs' set but not used [-Werror,-Wunused-but-set-variable]
int yynerrs;
^
/home/smarchi/src/binutils-gdb/gdb/yy-remap.h:58:18: note: expanded from macro 'yynerrs'
#define yynerrs GDB_YY_REMAP (yynerrs)
^
/home/smarchi/src/binutils-gdb/gdb/yy-remap.h:40:29: note: expanded from macro 'GDB_YY_REMAP'
#define GDB_YY_REMAP(YYSYM) GDB_YY_REMAP_1 (GDB_YY_REMAP_PREFIX, YYSYM)
^
/home/smarchi/src/binutils-gdb/gdb/yy-remap.h:39:39: note: expanded from macro 'GDB_YY_REMAP_1'
#define GDB_YY_REMAP_1(PREFIX, YYSYM) GDB_YY_REMAP_2 (PREFIX, YYSYM)
^
/home/smarchi/src/binutils-gdb/gdb/yy-remap.h:38:39: note: expanded from macro 'GDB_YY_REMAP_2'
#define GDB_YY_REMAP_2(PREFIX, YYSYM) PREFIX ## YYSYM
^
<scratch space>:45:1: note: expanded from here
cpnameyynerrs
^
This is because clang 15 warns for something like this:
int n;
n = 0;
++n;
whereas previous versions do not.
yynerrs is defined in yyparse and is there for actions to use. Since
the actions in cp-name-parser.y don't use it, we get a warning. We see
this problem on this particular .y file because it uses `%pure-parser`
[1], which makes yynerrs a local rather than a global.
I initially fixed this by using
DIAGNOSTIC_IGNORE_UNUSED_BUT_SET_VARIABLE (like in commit f7aa1a5acc5
("gold: Suppress "unused" variable warning on Clang")), but then I
realized we could suppress the warning in a more fine-grained way using
this in a rule:
(void) yynerrs;
[1] https://www.gnu.org/software/bison/manual/html_node/Error-Reporting-Function.html
Change-Id: I6cae7a4207c19fe1b719e2ac19be69122ebe3af1
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