Show fuzzy-stack-hash for crashes in debug build.

src/debug.c

@@ -62,6 +62,7 @@
 #endif
 
 #define MAX_TRACE_DEPTH   25
+#define MAX_HASH_DEPTH    10
 
 struct debug_info {
    A(debug_frame_t*) frames;
@@ -926,6 +927,22 @@ const debug_frame_t *debug_get_frame(debug_info_t *di, unsigned n)
    return AGET(di->frames, n);
 }
 
+hash_state_t debug_hash(debug_info_t *di)
+{
+   hash_state_t hash = HASH_INIT;
+   int hash_depth = 0;
+
+   const int nframes = debug_count_frames(di);
+   for (int n = 1; n < nframes; n++) {
+      const debug_frame_t *f = debug_get_frame(di, n);
+      if (f->kind == FRAME_PROG && f->symbol != NULL
+          && hash_depth++ < MAX_HASH_DEPTH)
+         hash_update(&hash, f->symbol, strlen(f->symbol));
+   }
+
+   return hash;
+}
+
 void debug_add_unwinder(void *start, size_t len, debug_unwind_fn_t fn,
                         void *context)
 {

src/debug.h

@@ -61,6 +61,7 @@ debug_info_t *debug_capture(void);
 void debug_free(debug_info_t *di);
 unsigned debug_count_frames(debug_info_t *di);
 const debug_frame_t *debug_get_frame(debug_info_t *di, unsigned n);
+hash_state_t debug_hash(debug_info_t *di);
 
 void debug_add_unwinder(void *start, size_t len, debug_unwind_fn_t fn,
                         void *context);

src/ident.c

@@ -29,9 +29,6 @@
 #include <ctype.h>
 #include <limits.h>
 
-#define HASH_INIT 5381;
-typedef uint32_t hash_state_t;
-
 #define INITIAL_SIZE  1024
 #define REPROBE_LIMIT 20
 #define MOVED_TAG     1
@@ -68,20 +65,6 @@ typedef struct {
 static ident_tab_t *table = NULL;
 static ident_tab_t *resizing = NULL;
 
-static inline int hash_update(hash_state_t *state, const char *key, int nchars)
-{
-   // DJB2 hash function from here:
-   //   http://www.cse.yorku.ca/~oz/hash.html
-
-   hash_state_t hash = *state;
-   const char *p = key;
-   for (; p < key + nchars && *p; p++)
-      hash = ((hash << 5) + hash) + *p;
-
-   *state = hash;
-   return p - key;
-}
-
 static ident_t ident_alloc(size_t len, hash_state_t hash)
 {
    ident_t id = xmalloc_flex(sizeof(struct _ident), len + 1, sizeof(char));

src/util.c

@@ -713,6 +713,10 @@ void show_stacktrace(void)
 
    }
 
+#ifdef DEBUG
+   color_fprintf(stderr, "\n$!red$Crash hash: %08x$$\n", debug_hash(di));
+#endif
+
    debug_free(di);
 
 #if defined __linux__ && !defined HAVE_LIBDW && !defined HAVE_LIBDWARF
@@ -2491,3 +2495,17 @@ void pool_stats(mem_pool_t *mp, size_t *alloc, size_t *npages)
       *alloc += p->alloc - sizeof(pool_page_t);
    }
 }
+
+int hash_update(hash_state_t *state, const char *key, int nchars)
+{
+   // DJB2 hash function from here:
+   //   http://www.cse.yorku.ca/~oz/hash.html
+
+   hash_state_t hash = *state;
+   const char *p = key;
+   for (; p < key + nchars && *p; p++)
+      hash = ((hash << 5) + hash) + *p;
+
+   *state = hash;
+   return p - key;
+}

src/util.h

@@ -514,4 +514,9 @@ void list_clear(ptr_list_t *l);
          __tmp;                                         \
       })
 
+#define HASH_INIT 5381;
+typedef uint32_t hash_state_t;
+
+int hash_update(hash_state_t *state, const char *key, int nchars);
+
 #endif // _UTIL_H