From 2ca9a54daaa0a955dabf38862cd777be359252e0 Mon Sep 17 00:00:00 2001
From: lemon <lsof@mailbox.org>
Date: Sat, 15 Nov 2025 19:53:47 +0100
Subject: ir: 'trap' jump; c: __builtin_trap; lex: __has_builtin

---
 c/builtin.c | 24 +++++++++++++++++++++---
 c/c.c       |  6 ++++--
 c/lex.c     | 29 +++++++++++++++++++++++++----
 3 files changed, 50 insertions(+), 9 deletions(-)

(limited to 'c')

diff --git a/c/builtin.c b/c/builtin.c
index d386480..23e1872 100644
--- a/c/builtin.c
+++ b/c/builtin.c
@@ -27,9 +27,9 @@ callcheck(const struct span *span, int nparam, const union type *param, int narg
 #define DEF_FNLIKE_SEMA(name, retty, ...)                                        \
    static bool                                                                   \
    name##_sema(struct comp *cm, struct expr *ex) {                               \
-      static union type par[] = { __VA_ARGS__, {0} };                            \
+      static union type par[] = { {{0}}, __VA_ARGS__ };                          \
       ex->ty = retty;                                                            \
-      return callcheck(&ex->span, arraylength(par)-1, par, ex->narg, ex->sub+1); \
+      return callcheck(&ex->span, arraylength(par)-1, par+1, ex->narg, ex->sub+1); \
    }
 
 static bool
@@ -63,6 +63,15 @@ va_end_comp(struct function *fn, struct expr *ex, bool discard)
    return NOREF;
 }
 
+DEF_FNLIKE_SEMA(trap, mktype(TYVOID), )
+
+static union ref
+trap_comp(struct function *fn, struct expr *ex, bool discard)
+{
+   puttrap(fn);
+   return NOREF;
+}
+
 union ref
 builtin_va_arg_comp(struct function *fn, const struct expr *ex, bool discard)
 {
@@ -74,6 +83,7 @@ builtin_va_arg_comp(struct function *fn, const struct expr *ex, bool discard)
 #define LIST_BUILTINS(_) \
    _(va_start) \
    _(va_end) \
+   _(trap)
 
 static const struct {
    const char *name;
@@ -84,11 +94,11 @@ static const struct {
 #undef FNS
 };
 
-const char *intern(const char *);
 void
 putbuiltins(struct env *env)
 {
    for (int i = 0; i < arraylength(tab); ++i) {
+      const char *intern(const char *);
       envadddecl(env, &(struct decl) {
          .name = intern(tab[i].name),
          .isbuiltin = 1,
@@ -97,5 +107,13 @@ putbuiltins(struct env *env)
    }
 }
 
+bool
+hasbuiltin(const char *name, uint len)
+{
+   for (int i = 0; i < arraylength(tab); ++i)
+      if (!strncmp(name, tab[i].name, len))
+         return 1;
+   return 0;
+}
 
 /* vim:set ts=3 sw=3 expandtab: */
diff --git a/c/c.c b/c/c.c
index 69efed6..fc6bcc0 100644
--- a/c/c.c
+++ b/c/c.c
@@ -3438,10 +3438,12 @@ compileexpr(struct function *fn, const struct expr *ex, bool discard)
          useblk(fn, tr);
          expreffects(fn, &sub[1]);
          end = newblk(fn);
-         putbranch(fn, end);
+         if (fn->curblk)
+            putbranch(fn, end);
          useblk(fn, fl);
          expreffects(fn, &sub[2]);
-         putbranch(fn, end);
+         if (fn->curblk)
+            putbranch(fn, end);
          useblk(fn, end);
          return NOREF;
       }
diff --git a/c/lex.c b/c/lex.c
index eab9ce3..60ce864 100644
--- a/c/lex.c
+++ b/c/lex.c
@@ -612,6 +612,7 @@ struct macro {
         const struct token *tk;
         int n;
       } rlist;
+      void (*handlerfn)(struct lexer *, struct token *ret, struct rlist arg);
    };
 };
 
@@ -988,7 +989,7 @@ tryexpand(struct lexer *lx, struct token *tk)
       if (l->macno == macidx)
          return 0;
 
-   if (mac->special) {
+   if (mac->special && !mac->fnlike) {
       mac->handler(lx, tk);
       pushmacstk(lx, &span, &(struct macrostack){
          .rlist = { alloccopy(lx->tmparena, tk, sizeof *tk, 0), 1 },
@@ -1080,9 +1081,13 @@ expandfnmacro(struct lexer *lx, struct span *span, struct macro *mac)
       joinspan(&excessspan.ex, tk.span.ex);
       error(&excessspan, "macro `%s' passed %d arguments, but takes just %d", mac->name, narg, mac->nparam);
    }
-
-   /* make new rlist with args replaced */
-   if (mac->nparam) {
+   if (mac->special) {
+      mac->handlerfn(lx, &tk, (struct rlist){argsbuf.p, argsbuf.n});
+      pushmacstk(lx, span, &(struct macrostack){
+         .rlist = { alloccopy(lx->tmparena, &tk, sizeof tk, 0), 1 },
+         .macno = mac - macros.p,
+      });
+   } else if (mac->nparam) { /* make new rlist with args replaced */
       struct token lhsargforpaste;
       bool lhsargpaste = 0, rhsargpaste = 0;
       for (int i = 0; i < mac->rlist.n; ++i) {
@@ -1896,6 +1901,21 @@ mac__time__handler(struct lexer *lx, struct token *tk)
    }
 }
 
+static void
+mac__has_builtin(struct lexer *lx, struct token *tk, struct rlist arg)
+{
+   extern bool hasbuiltin(const char *, uint n);
+   bool has = 0;
+   tk->t = TKNUMLIT, tk->len = 1;
+   if (arg.n == 1) {
+      if (arg.tk->t == TKIDENT)
+         has = hasbuiltin(arg.tk->s, arg.tk->len);
+      else if (in_range(arg.tk->t, TKWBEGIN_, TKWEND_))
+         has = arg.tk->len >= sizeof "__builtin_" && !memcmp(arg.tk->s, "__builtin_", 10);
+   }
+   tk->s = &"01"[has];
+}
+
 static void
 addpredefmacros(void)
 {
@@ -1906,6 +1926,7 @@ addpredefmacros(void)
       { "__LINE__", .predefined = 1, .special = 1, .handler = mac__line__handler },
       { "__DATE__", .predefined = 1, .special = 1, .handler = mac__date__handler },
       { "__TIME__", .predefined = 1, .special = 1, .handler = mac__time__handler },
+      { "__has_builtin", .predefined = 1, .nparam = 1, .fnlike = 1, .special = 1, .handlerfn = mac__has_builtin },
       { "__STDC__", .predefined = 1, .rlist = { &tok_1, 1 } },
       { "__STDC_VERSION__", .predefined = 1, .rlist = { &tok_ver, 1 } },
       { "__STDC_HOSTED__", .predefined = 1, .rlist = { &tok_1, 1 } },
-- 
cgit v1.2.3