kit

commit 78dd6876acf34875b49ae2aad972ddeb0a2b38e6
parent 5c3b6c310fe5a6c29007deca89a659d4a6f73438
Author: Ryan Sepassi <rsepassi@gmail.com>
Date:   Tue, 19 May 2026 14:45:15 -0700

Support #warning directive

Diffstat:
M
lang/c/pp/pp.c
 | 
1
+
M
lang/c/pp/pp_directive.c
 | 
36
+++++++++++++++++++++++++++++-------
M
lang/c/pp/pp_priv.h
 | 
1
+
A
test/pp/cases/b3_warning_directive.c
 | 
2
++
A
test/pp/cases/b3_warning_directive.expected
 | 
1
+

5 files changed, 34 insertions(+), 7 deletions(-)
diff --git a/lang/c/pp/pp.c b/lang/c/pp/pp.c
@@ -206,6 +206,7 @@ static void pp_intern_keywords(Pp* pp) {
   pp->sym_pragma = pool_intern_cstr(p, "pragma");
   pp->sym_pragma_kw = pp->sym_pragma;
   pp->sym_error = pool_intern_cstr(p, "error");
+  pp->sym_warning = pool_intern_cstr(p, "warning");
   pp->sym_embed = pool_intern_cstr(p, "embed");
   pp->sym_defined = pool_intern_cstr(p, "defined");
   pp->sym_va_args = pool_intern_cstr(p, "__VA_ARGS__");
diff --git a/lang/c/pp/pp_directive.c b/lang/c/pp/pp_directive.c
@@ -1014,24 +1014,44 @@ int try_expand_pragma_op(Pp* pp, const Tok* invoke) {
 }
 
 /* ============================================================
- * #error
+ * #error / #warning
  * ============================================================ */
 
-static void do_error(Pp* pp, const Tok* line, u32 n, SrcLoc loc) {
-  /* Concatenate token spellings into a single message. */
-  CharBuf cb = {0};
+static void directive_message(Pp* pp, const Tok* line, u32 n, CharBuf* cb) {
   u32 i;
   for (i = 0; i < n; ++i) {
     size_t sl = 0;
     const char* s =
         line[i].spelling ? pool_str(pp->pool, line[i].spelling, &sl) : NULL;
-    if (i > 0) cb_putc(pp, &cb, ' ');
-    if (s && sl) cb_append(pp, &cb, s, (u32)sl);
+    if (i > 0) cb_putc(pp, cb, ' ');
+    if (s && sl) cb_append(pp, cb, s, (u32)sl);
+  }
+  cb_putc(pp, cb, 0);
+}
+
+static void pp_warn(Pp* pp, SrcLoc loc, const char* fmt, ...) {
+  CfreeDiagSink* sink = cfree_compiler_diag_sink(pp->c);
+  va_list ap;
+  if (sink && sink->emit) {
+    va_start(ap, fmt);
+    sink->emit(sink, CFREE_DIAG_WARN, loc, fmt, ap);
+    va_end(ap);
   }
-  cb_putc(pp, &cb, 0);
+  if (sink) sink->warnings++;
+}
+
+static void do_error(Pp* pp, const Tok* line, u32 n, SrcLoc loc) {
+  CharBuf cb = {0};
+  directive_message(pp, line, n, &cb);
   compiler_panic(pp->c, loc, "#error: %s", cb.data ? cb.data : "");
 }
 
+static void do_warning(Pp* pp, const Tok* line, u32 n, SrcLoc loc) {
+  CharBuf cb = {0};
+  directive_message(pp, line, n, &cb);
+  pp_warn(pp, loc, "#warning: %s", cb.data ? cb.data : "");
+}
+
 /* ============================================================
  * #embed (C23, §6.10.* per N3033)
  * ============================================================ */
@@ -1244,6 +1264,8 @@ void process_directive(Pp* pp, SrcLoc hash_loc) {
     do_pragma(pp, line + 1, n - 1, hash_loc);
   else if (name == pp->sym_error)
     do_error(pp, line + 1, n - 1, hash_loc);
+  else if (name == pp->sym_warning)
+    do_warning(pp, line + 1, n - 1, hash_loc);
   else if (name == pp->sym_embed)
     do_embed(pp, line + 1, n - 1, hash_loc);
   else {
diff --git a/lang/c/pp/pp_priv.h b/lang/c/pp/pp_priv.h
@@ -138,6 +138,7 @@ struct Pp {
   Sym sym_line;
   Sym sym_pragma;
   Sym sym_error;
+  Sym sym_warning;
   Sym sym_embed;
   Sym sym_defined;
   Sym sym_va_args;
diff --git a/test/pp/cases/b3_warning_directive.c b/test/pp/cases/b3_warning_directive.c
@@ -0,0 +1,2 @@
+#warning "non-fatal diagnostic"
+int after_warning;
diff --git a/test/pp/cases/b3_warning_directive.expected b/test/pp/cases/b3_warning_directive.expected
@@ -0,0 +1 @@
+int after_warning;