Output of RawParser.c built by xcc differ from gcc

[mingodad]

While testing xcc with https://github.com/FransFaase/RawParser/blob/master/src/RawParser.c I noticed that it gives a different output than gcc:

./rawparser.gcc
OK: parsed white space
OK: parsed white space
OK: parsed value 0 from '0'
OK: parsed value 123 from '123'
OK: parsed ident 'aBc' from 'aBc'
OK: parsed ident '_123' from '_123'

./rawparser.chibicc
OK: parsed white space
OK: parsed white space
OK: parsed value 0 from '0'
OK: parsed value 123 from '123'
OK: parsed ident 'aBc' from 'aBc'
OK: parsed ident '_123' from '_123'

./rawparser.xcc
OK: parsed white space
OK: parsed white space
OK: parsed value 0 from '0'
OK: parsed value 123 from '123'
ERROR: failed to parse ident from 'aBc'
ERROR: failed to parse ident from '_123'

c2m rawparser.c -ei
OK: parsed white space
OK: parsed white space
OK: parsed value 0 from '0'
OK: parsed value 123 from '123'
ERROR: failed to parse ident from 'aBc'
ERROR: failed to parse ident from '_123'

[mingodad]

See this comment https://github.com/tyfkda/xcc/issues/96#issuecomment-1236076743 for the reason.

[mingodad]

I've been looking at c2mir.c to find a way to emit error/warning for function that doesn't return a value when declared to do so but couldn't find my way so far.

[mingodad]

After diving a bit more on c2mit.c code I found a way to start checking for function missing return:

diff --git a/c2mir/c2mir.c b/c2mir/c2mir.c
index 818d526..b60770f 100644
--- a/c2mir/c2mir.c
+++ b/c2mir/c2mir.c
@@ -5738,7 +5738,7 @@ struct node_scope {

 struct decl {
   /* true if address is taken, reg can be used or is used: */
-  unsigned addr_p : 1, reg_p : 1, used_p : 1;
+  unsigned addr_p : 1, reg_p : 1, used_p : 1, has_return:1;
   int bit_offset, width; /* for bitfields, -1 bit_offset for non bitfields. */
   mir_size_t offset;     /* var offset in frame or bss */
   node_t scope;          /* declaration scope */
@@ -7713,7 +7713,7 @@ static void init_decl (c2m_ctx_t c2m_ctx, decl_t decl) {
   check_ctx_t check_ctx = c2m_ctx->check_ctx;

   decl->addr_p = FALSE;
-  decl->reg_p = decl->used_p = FALSE;
+  decl->reg_p = decl->used_p = decl->has_return = FALSE;
   decl->offset = 0;
   decl->bit_offset = -1;
   decl->param_args_start = decl->param_args_num = 0;
@@ -9357,6 +9357,10 @@ static void check (c2m_ctx_t c2m_ctx, node_t r, node_t context) {
     ns = block->attr;
     ns->size = round_size (ns->size, MAX_ALIGNMENT);
     ns->size += ns->call_arg_area_size;
+    decl_t decl = r->attr;
+    if(decl->decl_spec.type->u.func_type->ret_type->u.basic_type != TP_VOID && !decl->has_return) {
+        error (c2m_ctx, POS (r), "no return in function returning non-void");
+    }
     break;
   }
   case N_TYPE: {
@@ -9627,6 +9631,7 @@ static void check (c2m_ctx_t c2m_ctx, node_t r, node_t context) {
     check_labels (c2m_ctx, labels, r);
     check (c2m_ctx, expr, r);
     ret_type = type->u.func_type->ret_type;
+    decl->has_return = TRUE;
     if (expr->code != N_IGNORE && void_type_p (ret_type)) {
       error (c2m_ctx, POS (r), "return with a value in function returning void");
     } else if (expr->code == N_IGNORE

And now when trying to compile/interpret the outdated RawParser.c attached here https://github.com/tyfkda/xcc/files/9482248/rawparser.c.zip I'm getting the desired output:

c2m rawparser.c -ei 
rawparser.c:1486:1: no return in function returning non-void
rawparser.c:1494:1: no return in function returning non-void
rawparser.c:1511:1: no return in function returning non-void
rawparser.c:1519:1: no return in function returning non-void

See also similar solution here https://github.com/tyfkda/xcc/issues/62 .