Merge pull request #32773 from JuliaLang/kf/32751

Fix missing GC root

Author: Keno

src/builtins.c

@@ -603,14 +603,16 @@ JL_CALLABLE(jl_f__apply)
             while (next != jl_nothing) {
                 roots[stackalloc] = next;
                 jl_value_t *value = jl_fieldref(next, 0);
-                roots[stackalloc + 1] = next;
+                roots[stackalloc + 1] = value;
                 jl_value_t *state = jl_fieldref(next, 1);
                 roots[stackalloc] = state;
                 _grow_to(&roots[0], &newargs, &arg_heap, &n_alloc, n + precount + 1, extra);
+                JL_GC_ASSERT_LIVE(value);
                 newargs[n++] = value;
                 if (arg_heap)
                     jl_gc_wb(arg_heap, value);
                 roots[stackalloc + 1] = NULL;
+                JL_GC_ASSERT_LIVE(state);
                 args[1] = state;
                 next = jl_apply_generic(jl_iterate_func, args, 2);
             }

src/julia_internal.h

@@ -1062,6 +1062,16 @@ extern arraylist_t partial_inst;
 #define JL_GCC_IGNORE_STOP
 #endif // _COMPILER_GCC_
 
+#ifdef __clang_analyzer__
+  // Not a safepoint (so it dosn't free other values), but an artificial use.
+  // Usually this is unnecessary because the analyzer can see all real uses,
+  // but sometimes real uses are harder for the analyzer to see, or it may
+  // give up before it sees it, so this can be helpful to be explicit.
+  void JL_GC_ASSERT_LIVE(jl_value_t *v) JL_NOTSAFEPOINT;
+#else
+  #define JL_GC_ASSERT_LIVE(x) (void)(x)
+#endif
+
 #ifdef __cplusplus
 }
 #endif

src/support/analyzer_annotations.h

@@ -45,5 +45,6 @@ extern "C" {
 #define JL_ROOTED_VALUE_COLLECTION
 #define JL_GC_PROMISE_ROOTED(x) (void)(x)
 #define jl_may_leak(x) (void)(x)
+#define JL_GC_ASSERT_LIVE(x)
 
 #endif