boot2

commit 75c2bc723023f8c895930d2c4855045d9eb8ed41
parent 8755ab3a67b482d417439ec467f2c6babda7dcab
Author: Ryan Sepassi <rsepassi@gmail.com>
Date:   Sun, 26 Apr 2026 22:39:39 -0700

cc tests: variadic call site exercises cg-promote per arg (§G.1)

Drives cg-call directly with cg-promote on each variadic arg before
push. Locks in the cg-side contract for §G.1 — parser-side per-arg
default-promote lands next.

Diffstat:
A
tests/cc-cg/66-vararg-call.expected-exit
 | 
1
+
A
tests/cc-cg/66-vararg-call.scm
 | 
57
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 58 insertions(+), 0 deletions(-)
diff --git a/tests/cc-cg/66-vararg-call.expected-exit b/tests/cc-cg/66-vararg-call.expected-exit
@@ -0,0 +1 @@
+16
diff --git a/tests/cc-cg/66-vararg-call.scm b/tests/cc-cg/66-vararg-call.scm
@@ -0,0 +1,57 @@
+;; tests/cc-cg/66-vararg-call.scm — variadic call with default-promoted args (§G.1).
+;; Models a variadic callee that just sums two int args after the named one.
+;;   int sum_var(int n, ...) {
+;;       int *ap = ((int*)(&n)) + 1;   /* hand-rolled vararg access */
+;;       return n + ap[0] + ap[1];
+;;   }
+;;   int main(void) {
+;;       signed char c = 5;
+;;       short      s = 10;
+;;       /* C semantics: c and s are promoted to int at the call site. */
+;;       return sum_var(1, c, s);   /* 1 + 5 + 10 = 16 */
+;;   }
+;;
+;; What the cc-cg fixture exercises is the *caller* side: cg-promote on
+;; each variadic arg before cg-call. The callee uses fixed-arg ABI here
+;; for simplicity; va_arg/va_start/va_end are §G.2.
+
+(let* ((cg          (cg-init))
+       (sumv-fnty   (%ctype 'fn 8 8 (cons %t-i32 (cons (list %t-i32) #t))))
+       (sumv-sym    (%sym "sum_var" 'fn 'extern sumv-fnty #f)))
+  ;; int sum_var(int n, int a, int b) { return n + a + b; }
+  ;; (Modeling 3 fixed params; the callee doesn't care about variadic
+  ;; ABI in this fixture — see §G.2 for that.)
+  (let* ((params (cg-fn-begin cg "sum_var"
+                              (list (cons "n" %t-i32)
+                                    (cons "a" %t-i32)
+                                    (cons "b" %t-i32))
+                              %t-i32))
+         (n* (cdr (car params)))
+         (a* (cdr (car (cdr params))))
+         (b* (cdr (car (cdr (cdr params))))))
+    (cg-push-sym cg n*) (cg-load cg)
+    (cg-push-sym cg a*) (cg-load cg) (cg-binop cg 'add)
+    (cg-push-sym cg b*) (cg-load cg) (cg-binop cg 'add)
+    (cg-return cg)
+    (cg-fn-end cg))
+  ;; int main(void) { signed char c=5; short s=10; return sum_var(1, c, s); }
+  (let* ((params (cg-fn-begin cg "main" '() %t-i32))
+         (c-sl   (cg-alloc-slot cg 1 1))
+         (s-sl   (cg-alloc-slot cg 2 2))
+         (c-sym  (%sym "c" 'var 'auto %t-i8  c-sl))
+         (s-sym  (%sym "s" 'var 'auto %t-i16 s-sl)))
+    ;; c = 5;
+    (cg-push-sym cg c-sym) (cg-push-imm cg %t-i32 5)
+    (cg-assign cg) (cg-pop cg)
+    ;; s = 10;
+    (cg-push-sym cg s-sym) (cg-push-imm cg %t-i32 10)
+    (cg-assign cg) (cg-pop cg)
+    ;; sum_var(1, c, s) — promote c and s to int at the call site
+    (cg-push-sym cg sumv-sym)
+    (cg-push-imm cg %t-i32 1)               ; named-arg n
+    (cg-push-sym cg c-sym) (cg-load cg) (cg-promote cg)   ; variadic c
+    (cg-push-sym cg s-sym) (cg-load cg) (cg-promote cg)   ; variadic s
+    (cg-call cg 3 #t)
+    (cg-return cg)
+    (cg-fn-end cg))
+  (write-bv-fd 1 (cg-finish cg)))