From f38a0bde21776f6a8e92b73645c3d54764c85459 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 20 Sep 2022 12:04:37 -0400 Subject: [PATCH] Suppress variable-set-but-not-used warnings from clang 15. clang 15+ will issue a set-but-not-used warning when the only use of a variable is in autoincrements (e.g., "foo++;"). That's perfectly sensible, but it detects a few more cases that we'd not noticed before. Silence the warnings with our usual methods, such as PG_USED_FOR_ASSERTS_ONLY, or in one case by actually removing a useless variable. One thing that we can't nicely get rid of is that with %pure-parser, Bison emits "yynerrs" as a local variable that falls foul of this warning. To silence those, I inserted "(void) yynerrs;" in the top-level productions of affected grammars. Per recently-established project policy, this is a candidate for back-patching into out-of-support branches: it suppresses annoying compiler warnings but changes no behavior. Hence, back-patch to 9.5, which is as far as these patches go without issues. (A preliminary check shows that the prior branches need some other set-but-not-used cleanups too, so I'll leave them for another day.) Discussion: https://postgr.es/m/514615.1663615243@sss.pgh.pa.us --- src/backend/access/gist/gistxlog.c | 2 +- src/backend/access/transam/xlog.c | 2 +- src/backend/parser/gram.y | 1 + src/backend/utils/adt/array_typanalyze.c | 4 +--- src/backend/utils/adt/jsonpath_gram.y | 1 + src/bin/pgbench/exprparse.y | 5 ++++- 6 files changed, 9 insertions(+), 6 deletions(-) diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c index 3b28f546465..4daf3ba2124 100644 --- a/src/backend/access/gist/gistxlog.c +++ b/src/backend/access/gist/gistxlog.c @@ -81,7 +81,7 @@ gistRedoPageUpdateRecord(XLogReaderState *record) char *begin; char *data; Size datalen; - int ninserted = 0; + int ninserted PG_USED_FOR_ASSERTS_ONLY = 0; data = begin = XLogRecGetBlockData(record, 0, &datalen); diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 443ee90b5a1..36e077045b9 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -2106,7 +2106,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic) XLogRecPtr NewPageEndPtr = InvalidXLogRecPtr; XLogRecPtr NewPageBeginPtr; XLogPageHeader NewPage; - int npages = 0; + int npages pg_attribute_unused() = 0; LWLockAcquire(WALBufMappingLock, LW_EXCLUSIVE); diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 9de9dbd8a8a..e820606338c 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -789,6 +789,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); stmtblock: stmtmulti { pg_yyget_extra(yyscanner)->parsetree = $1; + (void) yynerrs; /* suppress compiler warning */ } ; diff --git a/src/backend/utils/adt/array_typanalyze.c b/src/backend/utils/adt/array_typanalyze.c index eafb94b697e..f8fd6cb8cb5 100644 --- a/src/backend/utils/adt/array_typanalyze.c +++ b/src/backend/utils/adt/array_typanalyze.c @@ -218,7 +218,6 @@ compute_array_stats(VacAttrStats *stats, AnalyzeAttrFetchFunc fetchfunc, { ArrayAnalyzeExtraData *extra_data; int num_mcelem; - int null_cnt = 0; int null_elem_cnt = 0; int analyzed_rows = 0; @@ -322,8 +321,7 @@ compute_array_stats(VacAttrStats *stats, AnalyzeAttrFetchFunc fetchfunc, value = fetchfunc(stats, array_no, &isnull); if (isnull) { - /* array is null, just count that */ - null_cnt++; + /* ignore arrays that are null overall */ continue; } diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y index 99a995d0b1c..7ecbd918595 100644 --- a/src/backend/utils/adt/jsonpath_gram.y +++ b/src/backend/utils/adt/jsonpath_gram.y @@ -128,6 +128,7 @@ result: *result = palloc(sizeof(JsonPathParseResult)); (*result)->expr = $2; (*result)->lax = $1; + (void) yynerrs; } | /* EMPTY */ { *result = NULL; } ; diff --git a/src/bin/pgbench/exprparse.y b/src/bin/pgbench/exprparse.y index 17c9ec32c50..250064c23be 100644 --- a/src/bin/pgbench/exprparse.y +++ b/src/bin/pgbench/exprparse.y @@ -79,7 +79,10 @@ static PgBenchExpr *make_case(yyscan_t yyscanner, PgBenchExprList *when_then_lis %% -result: expr { expr_parse_result = $1; } +result: expr { + expr_parse_result = $1; + (void) yynerrs; /* suppress compiler warning */ + } elist: { $$ = NULL; } | expr { $$ = make_elist($1, NULL); }