From 716bb331b9cee828ea8249265cf50355d961859f Mon Sep 17 00:00:00 2001
From: Gareth Rees <gdr@ravenbrook.com>
Date: Fri, 26 Sep 2014 21:35:25 +0100
Subject: [PATCH] Use the nelems macro to compute the size of arrays.

Copied from Perforce
 Change: 187055
 ServerID: perforce.ravenbrook.com
---
 mps/code/amcssth.c  | 4 ++--
 mps/code/djbench.c  | 2 +-
 mps/code/eventsql.c | 6 +++---
 mps/code/gcbench.c  | 2 +-
 mps/code/misc.h     | 4 ++--
 mps/code/steptest.c | 4 +---
 mps/code/testlib.c  | 8 ++++----
 7 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/mps/code/amcssth.c b/mps/code/amcssth.c
index f4dedd55f7f..59b48ff27c4 100644
--- a/mps/code/amcssth.c
+++ b/mps/code/amcssth.c
@@ -222,7 +222,7 @@ static void test_pool(mps_pool_t pool, size_t roots_count, int mode)
   cl.pool = pool;
   cl.roots_count = roots_count;
 
-  for (i = 0; i < sizeof(kids)/sizeof(kids[0]); ++i)
+  for (i = 0; i < NELEMS(kids); ++i)
     testthr_create(&kids[i], kid_thread, &cl);
 
   die(mps_ap_create(&ap, pool, mps_rank_exact()), "BufferCreate");
@@ -306,7 +306,7 @@ static void test_pool(mps_pool_t pool, size_t roots_count, int mode)
   mps_ap_destroy(busy_ap);
   mps_ap_destroy(ap);
 
-  for (i = 0; i < sizeof(kids)/sizeof(kids[0]); ++i)
+  for (i = 0; i < NELEMS(kids); ++i)
     testthr_join(&kids[i], NULL);
 }
 
diff --git a/mps/code/djbench.c b/mps/code/djbench.c
index 2eafe724522..9379a259669 100644
--- a/mps/code/djbench.c
+++ b/mps/code/djbench.c
@@ -356,7 +356,7 @@ int main(int argc, char *argv[]) {
   (void)fflush(stdout);
 
   while (argc > 0) {
-    for (i = 0; i < sizeof(pools) / sizeof(pools[0]); ++i)
+    for (i = 0; i < NELEMS(pools); ++i)
       if (strcmp(argv[0], pools[i].name) == 0)
         goto found;
     fprintf(stderr, "unknown pool test \"%s\"\n", argv[0]);
diff --git a/mps/code/eventsql.c b/mps/code/eventsql.c
index e1c9ea22381..08838620777 100644
--- a/mps/code/eventsql.c
+++ b/mps/code/eventsql.c
@@ -386,7 +386,7 @@ static void testTableExists(sqlite3 *db)
   size_t i;
   int defects = 0;
   int tests = 0;
-  for (i=0; i < (sizeof(tableTests)/sizeof(tableTests[0])); ++i) {
+  for (i=0; i < NELEMS(tableTests); ++i) {
     const char *name = tableTests[i].name;
     int exists = tableExists(db, name);
     if (exists)
@@ -566,7 +566,7 @@ static void makeTables(sqlite3 *db)
   size_t i;
   evlog(LOG_SOMETIMES, "Creating tables.");
         
-  for (i=0; i < (sizeof(createStatements)/sizeof(createStatements[0])); ++i) {
+  for (i=0; i < NELEMS(createStatements); ++i) {
     runStatement(db, createStatements[i], "Table creation");
   }
 }
@@ -585,7 +585,7 @@ static void dropGlueTables(sqlite3 *db)
 
   evlog(LOG_ALWAYS, "Dropping glue tables so they are rebuilt.");
         
-  for (i=0; i < (sizeof(glueTables)/sizeof(glueTables[0])); ++i) {
+  for (i=0; i < NELEMS(glueTables); ++i) {
     evlog(LOG_SOMETIMES, "Dropping table %s", glueTables[i]);
     sprintf(sql, "DROP TABLE %s", glueTables[i]);
     res = sqlite3_exec(db,
diff --git a/mps/code/gcbench.c b/mps/code/gcbench.c
index 0dc3ef3ded8..0f02f8040db 100644
--- a/mps/code/gcbench.c
+++ b/mps/code/gcbench.c
@@ -449,7 +449,7 @@ int main(int argc, char *argv[]) {
   (void)fflush(stdout);
 
   while (argc > 0) {
-    for (i = 0; i < sizeof(pools) / sizeof(pools[0]); ++i)
+    for (i = 0; i < NELEMS(pools); ++i)
       if (strcmp(argv[0], pools[i].name) == 0)
         goto found;
     fprintf(stderr, "unknown pool test \"%s\"\n", argv[0]);
diff --git a/mps/code/misc.h b/mps/code/misc.h
index c07647f54db..9b22522558a 100644
--- a/mps/code/misc.h
+++ b/mps/code/misc.h
@@ -102,8 +102,8 @@ typedef const struct SrcIdStruct {
  * NELEMS(a) expands into an expression that is the number
  * of elements in the array a.
  *
- * WARNING: expands a more than once (you'd have to write obviously
- * perverse code for this to matter though).
+ * WARNING: expands a more than once (but only in the context of
+ * sizeof, so does not cause double evaluation).
  */
 
 #define NELEMS(a) (sizeof(a)/sizeof((a)[0]))
diff --git a/mps/code/steptest.c b/mps/code/steptest.c
index 546eaa7e417..a66b85f1195 100644
--- a/mps/code/steptest.c
+++ b/mps/code/steptest.c
@@ -56,8 +56,6 @@ static unsigned long step_frequencies[] = {
     1000000000, /* one billion */
 };
 
-#define TESTS (sizeof(step_frequencies) / sizeof(step_frequencies[0]))
-
 static unsigned test_number = 0;
 
 
@@ -496,7 +494,7 @@ int main(int argc, char *argv[])
 
     testlib_init(argc, argv);
 
-    while (test_number < TESTS) {
+    while (test_number < NELEMS(step_frequencies)) {
         mps_arena_t arena;
         mps_thr_t thread;
         void *r;
diff --git a/mps/code/testlib.c b/mps/code/testlib.c
index 5b8b17d5ef2..401c4059938 100644
--- a/mps/code/testlib.c
+++ b/mps/code/testlib.c
@@ -325,9 +325,9 @@ void rnd_state_set_v2(unsigned long seed0_v2)
 static struct {
   const char *ident;
   const char *doc;
-} res_strings[] = {
-#define RES_STRINGS_ROW(X, ident, doc) {#ident, #doc},
-_mps_RES_ENUM(RES_STRINGS_ROW, X)
+} const res_strings[] = {
+#define RES_STRINGS_ROW(X, ident, doc) {#ident, doc},
+  _mps_RES_ENUM(RES_STRINGS_ROW, X)
 };
 
 
@@ -372,7 +372,7 @@ void error(const char *format, ...)
 void die_expect(mps_res_t res, mps_res_t expected, const char *s)
 {
   if (res != expected) {
-    if (0 <= res && (unsigned)res < sizeof(res_strings) / sizeof(res_strings[0]))
+    if (0 <= res && (unsigned)res < NELEMS(res_strings))
       error("\n%s: %s: %s\n", s, res_strings[res].ident, res_strings[res].doc);
     else
       error("\n%s: %d: unknown result code\n", s, res);