Merge pull request erlang#9417 from jhogberg/john/erts/suppress-gcc-w…

…arnings/erlangGH-9413/OTP-19488 erts: Suppress various NULL-pointer warnings
garazdawi · Feb 19, 2025 · 19391bb · 19391bb
2 parents be3ca1a + 8d8fa19
commit 19391bb
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Showing 3 changed files with 39 additions and 3 deletions.
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
@@ -3194,11 +3194,11 @@ void erts_schedule_dist_command(Port *prt, DistEntry *dist_entry)
 		& ERTS_PORT_SFLGS_DEAD) == 0);
 
         dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
-        ASSERT(dep);
+        ERTS_ASSUME(dep);
 	id = prt->common.id;
     }
     else {
-	ASSERT(dist_entry);
+	ERTS_ASSUME(dist_entry);
 	ERTS_LC_ASSERT(erts_lc_rwmtx_is_rlocked(&dist_entry->rwmtx)
 			   || erts_lc_rwmtx_is_rwlocked(&dist_entry->rwmtx));
 	ASSERT(is_internal_port(dist_entry->cid));
@@ -3773,6 +3773,9 @@ dist_port_commandv(Port *prt, ErtsDistOutputBuf *obuf)
 #ifdef USE_VM_PROBES
     if (DTRACE_ENABLED(dist_outputv)) {
         DistEntry *dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
+
+        ERTS_ASSUME(dep);
+
         DTRACE_CHARBUF(port_str, 64);
         DTRACE_CHARBUF(remote_str, 64);
 
@@ -3878,6 +3881,7 @@ erts_dist_command(Port *prt, int initial_reds)
 
     ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
 
+    ERTS_ASSUME(dep);
     erts_atomic_set_mb(&dep->dist_cmd_scheduled, 0);
 
     erts_de_rlock(dep);
@@ -4625,6 +4629,9 @@ erts_dist_port_not_busy(Port *prt)
 #ifdef USE_VM_PROBES
     if (DTRACE_ENABLED(dist_port_not_busy)) {
         DistEntry *dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
+
+        ERTS_ASSUME(dep);
+
         DTRACE_CHARBUF(port_str, 64);
         DTRACE_CHARBUF(remote_str, 64);
 

diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
@@ -3903,7 +3903,9 @@ erts_deliver_port_exit(Port *prt, Eterm from, Eterm reason, int send_closed,
 
    if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
        DistEntry *dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
-       ASSERT(dep);
+
+       ERTS_ASSUME(dep);
+
        erts_do_net_exits(dep, modified_reason);
        erts_deref_dist_entry(dep);
        erts_prtsd_set(prt, ERTS_PRTSD_DIST_ENTRY, NULL);
@@ -6345,7 +6347,11 @@ int driver_output_binary(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
     if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
         DistEntry* dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
         Uint32 conn_id = (Uint32)(UWord) erts_prtsd_get(prt, ERTS_PRTSD_CONN_ID);
+
+        ERTS_ASSUME(dep);
+
         erts_atomic64_inc_nob(&dep->in);
+
 	return erts_net_message(prt,
 				dep,
                                 conn_id,
@@ -6390,7 +6396,11 @@ int driver_output2(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
     if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
         DistEntry *dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
         Uint32 conn_id = (Uint32)(UWord) erts_prtsd_get(prt, ERTS_PRTSD_CONN_ID);
+
+        ERTS_ASSUME(dep);
+
         erts_atomic64_inc_nob(&dep->in);
+
 	if (len == 0)
 	    return erts_net_message(prt,
 				    dep,

diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
@@ -177,6 +177,25 @@ typedef ERTS_SYS_FD_TYPE ErtsSysFdType;
 #  define ERTS_UNLIKELY(BOOL) (BOOL)
 #endif
 
+#if (ERTS_AT_LEAST_GCC_VSN__(5, 1, 0) || __has_builtin(__builtin_unreachable))
+#  define ERTS_UNREACHABLE __builtin_unreachable()
+#elif defined(_MSC_VER)
+#  define ERTS_UNREACHABLE __assume(0)
+#else
+/* Unsupported compiler, just ignore it. */
+#  define ERTS_UNREACHABLE ((void)0)
+#endif
+
+/* Tells the compiler to assume that a certain fact always holds, suppressing
+ * bogus warnings and/or enabling better optimizations. */
+#if !defined(DEBUG)
+#  define ERTS_ASSUME(Expr) ((Expr) ?                                          \
+                             (void)0 :                                         \
+                             (void)ERTS_UNREACHABLE)
+#else
+#  define ERTS_ASSUME(Expr) ASSERT((Expr))
+#endif
+
 /* AIX doesn't like this and claims section conflicts */
 #if ERTS_AT_LEAST_GCC_VSN__(2, 96, 0) && !defined(_AIX)
 #if (defined(__APPLE__) && defined(__MACH__)) || defined(__DARWIN__)