Replace uses of xnew(T, 1) with xmalloc(sizeof(*t))

For allocating single objects, this macro didn't serve any particular
purpose and only obscured things compared to the more familiar/direct
use of `xmalloc()`.

The array allocation cases have been left as-is, except that the macro
now expands to `xmallocarray(...)` and gains a proper `ALLOC_SIZE()`
annotation.

src/compiler.c

@@ -44,7 +44,7 @@ void add_error_fmt (
     int8_t idx[NR_ERRFMT_INDICES],
     bool ignore
 ) {
-    ErrorFormat *f = xnew(ErrorFormat, 1);
+    ErrorFormat *f = xmalloc(sizeof(*f));
     f->ignore = ignore;
     f->re = *re; // Takes ownership (responsible for calling regfree(3))
     memcpy(f->capture_index, idx, NR_ERRFMT_INDICES);

src/editor.c

@@ -69,7 +69,7 @@ static mode_t get_umask(void)
 
 EditorState *init_editor_state(EditorFlags flags)
 {
-    EditorState *e = xnew(EditorState, 1);
+    EditorState *e = xmalloc(sizeof(*e));
     *e = (EditorState) {
         .status = EDITOR_INITIALIZING,
         .flags = flags,

src/file-history.c

@@ -46,7 +46,7 @@ void file_history_append(FileHistory *history, unsigned long row, unsigned long
             e = hashmap_remove(map, old_first->filename);
             BUG_ON(e != old_first);
         } else {
-            e = xnew(FileHistoryEntry, 1);
+            e = xmalloc(sizeof(*e));
         }
         e->filename = xstrdup(filename);
         hashmap_insert(map, e->filename, e);

src/file-option.c

@@ -120,7 +120,7 @@ void add_file_options (
         BUG_ON(!u.filetype);
     }
 
-    FileOption *opt = xnew(FileOption, 1);
+    FileOption *opt = xmalloc(sizeof(*opt));
     opt->u = u;
     opt->type = type;
     opt->strs = copy_string_array(strs, nstrs);

src/history.c

@@ -41,7 +41,7 @@ void history_append(History *history, const char *text)
             e = hashmap_remove(map, old_first->text);
             BUG_ON(e != old_first);
         } else {
-            e = xnew(HistoryEntry, 1);
+            e = xmalloc(sizeof(*e));
         }
         e->text = xstrdup(text);
         hashmap_insert(map, e->text, e);

src/regexp.c

@@ -130,7 +130,7 @@ const InternedRegexp *regexp_intern(ErrorBuffer *ebuf, const char *pattern)
         return ir;
     }
 
-    ir = xnew(InternedRegexp, 1);
+    ir = xmalloc(sizeof(*ir));
     int err = regcomp(&ir->re, pattern, DEFAULT_REGEX_FLAGS | REG_NEWLINE | REG_NOSUB);
     if (unlikely(err)) {
         regexp_error_msg(ebuf, &ir->re, pattern, err);

src/syntax/highlight.c

@@ -62,7 +62,7 @@ static State *handle_heredoc (
         .delim_len = len
     };
 
-    HeredocState *s = xnew(HeredocState, 1);
+    HeredocState *s = xmalloc(sizeof(*s));
     *s = (HeredocState) {
         .state = merge_syntax(syn, &m, sm),
         .delim = delim,

src/tag.c

@@ -222,11 +222,11 @@ static void tag_file_find_tags (
     const StringView *name,
     PointerArray *tags
 ) {
-    Tag *t = xnew(Tag, 1);
+    Tag *t = xmalloc(sizeof(*t));
     size_t pos = 0;
     while (next_tag(tf->buf, tf->size, &pos, name, true, t)) {
         ptr_array_append(tags, t);
-        t = xnew(Tag, 1);
+        t = xmalloc(sizeof(*t));
     }
     free(t);
 

src/util/xmalloc.h

@@ -7,7 +7,7 @@
 #include "macros.h"
 
 #define XMEMDUP(ptr) xmemdup(ptr, sizeof(*ptr))
-#define xnew(type, n) xmalloc(xmul(sizeof(type), (n)))
+#define xnew(type, n) xmallocarray((n), sizeof(type))
 #define xnew0(type, n) xcalloc((n), sizeof(type))
 #define xrenew(mem, n) xreallocarray(mem, (n), sizeof(*mem))
 
@@ -40,6 +40,12 @@ static inline size_t xadd3(size_t a, size_t b, size_t c)
     return xadd(a, xadd(b, c));
 }
 
+XMALLOC ALLOC_SIZE(1, 2)
+static inline void *xmallocarray(size_t nmemb, size_t size)
+{
+    return xmalloc(xmul(nmemb, size));
+}
+
 RETURNS_NONNULL WARN_UNUSED_RESULT ALLOC_SIZE(2, 3)
 static inline void *xreallocarray(void *ptr, size_t nmemb, size_t size)
 {
@@ -65,6 +71,7 @@ static inline char *xstrcut(const char *str, size_t size)
 XSTRDUP
 static inline char *xstrslice(const char *str, size_t pos, size_t end)
 {
+    BUG_ON(pos > end);
     return xstrcut(str + pos, end - pos);
 }
 

src/window.c

@@ -26,7 +26,7 @@ View *window_add_buffer(Window *window, Buffer *buffer)
     // View::selection and View::select_mode
     static_assert(SELECT_NONE == 0);
 
-    View *view = xnew(View, 1);
+    View *view = xmalloc(sizeof(*view));
     *view = (View) {
         .buffer = buffer,
         .window = window,