Make eligible global variables static and/or const

For better or worse, Jemalloc has a significant number of global
variables. Making all eligible global variables `static` and/or `const`
at least makes it slightly easier to reason about them, as these
qualifications communicate to the programmer restrictions on their use
without having to `grep` the whole codebase.

src/arena.c

@@ -21,7 +21,7 @@ JEMALLOC_DIAGNOSTIC_DISABLE_SPURIOUS
  * Define names for both unininitialized and initialized phases, so that
  * options and mallctl processing are straightforward.
  */
-const char *percpu_arena_mode_names[] = {
+const char *const percpu_arena_mode_names[] = {
 	"percpu",
 	"phycpu",
 	"disabled",
@@ -37,7 +37,7 @@ static atomic_zd_t dirty_decay_ms_default;
 static atomic_zd_t muzzy_decay_ms_default;
 
 emap_t arena_emap_global;
-pa_central_t arena_pa_central_global;
+static pa_central_t arena_pa_central_global;
 
 div_info_t arena_binind_div_info[SC_NBINS];
 

src/base.c

@@ -22,7 +22,7 @@ static base_t *b0;
 
 metadata_thp_mode_t opt_metadata_thp = METADATA_THP_DEFAULT;
 
-const char *metadata_thp_mode_names[] = {
+const char *const metadata_thp_mode_names[] = {
 	"disabled",
 	"auto",
 	"always"

src/extent_dss.c

@@ -10,7 +10,7 @@
 
 const char	*opt_dss = DSS_DEFAULT;
 
-const char	*dss_prec_names[] = {
+const char	*const dss_prec_names[] = {
 	"disabled",
 	"primary",
 	"secondary",

src/hpa_hooks.c

@@ -11,7 +11,7 @@ static void hpa_hooks_dehugify(void *ptr, size_t size);
 static void hpa_hooks_curtime(nstime_t *r_nstime, bool first_reading);
 static uint64_t hpa_hooks_ms_since(nstime_t *past_nstime);
 
-hpa_hooks_t hpa_hooks_default = {
+const hpa_hooks_t hpa_hooks_default = {
 	&hpa_hooks_map,
 	&hpa_hooks_unmap,
 	&hpa_hooks_purge,

src/jemalloc.c

@@ -121,7 +121,7 @@ zero_realloc_action_t opt_zero_realloc_action =
 
 atomic_zu_t zero_realloc_count = ATOMIC_INIT(0);
 
-const char *zero_realloc_mode_names[] = {
+const char *const zero_realloc_mode_names[] = {
 	"alloc",
 	"free",
 	"abort",
@@ -142,8 +142,8 @@ static void default_junk_free(void *ptr, size_t usize) {
 	memset(ptr, junk_free_byte, usize);
 }
 
-void (*junk_alloc_callback)(void *ptr, size_t size) = &default_junk_alloc;
-void (*junk_free_callback)(void *ptr, size_t size) = &default_junk_free;
+void (*JET_MUTABLE junk_alloc_callback)(void *ptr, size_t size) = &default_junk_alloc;
+void (*JET_MUTABLE junk_free_callback)(void *ptr, size_t size) = &default_junk_free;
 
 bool	opt_utrace = false;
 bool	opt_xmalloc = false;
@@ -158,7 +158,7 @@ unsigned opt_debug_double_free_max_scan =
     SAFETY_CHECK_DOUBLE_FREE_MAX_SCAN_DEFAULT;
 
 /* Protects arenas initialization. */
-malloc_mutex_t arenas_lock;
+static malloc_mutex_t arenas_lock;
 
 /* The global hpa, and whether it's on. */
 bool opt_hpa = false;

src/nstime.c

@@ -228,7 +228,7 @@ nstime_monotonic_t *JET_MUTABLE nstime_monotonic = nstime_monotonic_impl;
 prof_time_res_t opt_prof_time_res =
 	prof_time_res_default;
 
-const char *prof_time_res_mode_names[] = {
+const char *const prof_time_res_mode_names[] = {
 	"default",
 	"high",
 };

src/pa.c

@@ -17,7 +17,7 @@ pa_nactive_sub(pa_shard_t *shard, size_t sub_pages) {
 
 bool
 pa_central_init(pa_central_t *central, base_t *base, bool hpa,
-    hpa_hooks_t *hpa_hooks) {
+    const hpa_hooks_t *hpa_hooks) {
 	bool err;
 	if (hpa) {
 		err = hpa_central_init(&central->hpa, base, hpa_hooks);

src/pages.c

@@ -42,7 +42,7 @@ static int	mmap_flags;
 #endif
 static bool	os_overcommits;
 
-const char *thp_mode_names[] = {
+const char *const thp_mode_names[] = {
 	"default",
 	"always",
 	"never",

src/prof.c

@@ -73,16 +73,16 @@ static malloc_mutex_t next_thr_uid_mtx;
 bool prof_booted = false;
 
 /* Logically a prof_backtrace_hook_t. */
-atomic_p_t prof_backtrace_hook;
+static atomic_p_t prof_backtrace_hook;
 
 /* Logically a prof_dump_hook_t. */
-atomic_p_t prof_dump_hook;
+static atomic_p_t prof_dump_hook;
 
 /* Logically a prof_sample_hook_t. */
-atomic_p_t prof_sample_hook;
+static atomic_p_t prof_sample_hook;
 
 /* Logically a prof_sample_free_hook_t. */
-atomic_p_t prof_sample_free_hook;
+static atomic_p_t prof_sample_free_hook;
 
 /******************************************************************************/
 

src/prof_log.c

@@ -25,7 +25,7 @@ enum prof_logging_state_e {
  * - started: log_start called, log_stop not called yet. Allocations are logged.
  * - dumping: log_stop called but not finished; samples are not logged anymore.
  */
-prof_logging_state_t prof_logging_state = prof_logging_state_stopped;
+static prof_logging_state_t prof_logging_state = prof_logging_state_stopped;
 
 /* Used in unit tests. */
 static bool prof_log_dummy = false;

src/prof_sys.c

@@ -27,8 +27,6 @@
 
 malloc_mutex_t prof_dump_filename_mtx;
 
-bool prof_do_mock = false;
-
 static uint64_t prof_dump_seq;
 static uint64_t prof_dump_iseq;
 static uint64_t prof_dump_mseq;

src/stats.c

@@ -9,13 +9,13 @@
 #include "jemalloc/internal/mutex_prof.h"
 #include "jemalloc/internal/prof_stats.h"
 
-const char *global_mutex_names[mutex_prof_num_global_mutexes] = {
+static const char *const global_mutex_names[mutex_prof_num_global_mutexes] = {
 #define OP(mtx) #mtx,
 	MUTEX_PROF_GLOBAL_MUTEXES
 #undef OP
 };
 
-const char *arena_mutex_names[mutex_prof_num_arena_mutexes] = {
+static const char *const arena_mutex_names[mutex_prof_num_arena_mutexes] = {
 #define OP(mtx) #mtx,
 	MUTEX_PROF_ARENA_MUTEXES
 #undef OP