commit cade790ded0af7fc59a2318afa8f63f3dd226be3
parent 3c5314adf20422fa3616120e78e0d1d23ce95d46
Author: Ryan Sepassi <rsepassi@gmail.com>
Date: Wed, 29 Apr 2026 20:21:43 -0700
va_list: route through __builtin_va_list across cc.scm + mes-libc
Previously the flattened source landed `typedef char *va_list;` and
inline `(ap) = (char*)(&fmt) + sizeof(void*)` / `(ap) = 0` macros —
the tcc/mes stage1 convention, which assumes x86-style stack-passed
varargs. cc.scm tolerated this because P1 spills all args to slots,
but stock gcc/clang reject it under their struct-shaped va_list ABI.
Three coordinated changes let a single source compile cleanly under
both:
- cc.scm parse-decl-spec recognizes __builtin_va_list as a builtin
type alias for char* (cg-va-{start,arg,end} only need an 8-byte
pointer slot).
- New vendor/boot2-include/stdarg.h shadows mes/include/stdarg.h
with `typedef __builtin_va_list va_list;` and macros routed
through __builtin_va_*.
- libc-flatten.sh adds -I vendor/boot2-include ahead of mes's tree
so the shim wins for both the libc-flatten and the tcc-flatten
paths (stage1-flatten gets the same -I in a separate commit).
The previous in-source patch (vendor/mes-libc/patches/stdarg-builtin)
is now redundant — deleted, along with the original stdarg.h.
Validated by stock gcc + libgcc on aarch64 musl: tcc-gcc -version
runs to "tcc version 0.9.26 (x86_64 Linux)" exit 0 with no source
patches, and cc.scm-built tcc-boot2 still reaches the same crash
site (no behavioural change in the cc.scm path).
Diffstat:
6 files changed, 62 insertions(+), 133 deletions(-)
diff --git a/cc/cc.scm b/cc/cc.scm
@@ -2821,7 +2821,7 @@
;; and same-size casts round-trip the bytes; widening int→fp casts
;; leave the int bit-pattern in the wider slot; binops use integer
;; ALU ops. tcc.flat.c contains real fp code paths (parse_number,
-;; ieee_finite, …) that the bootstrap tcc-lispcc never executes when
+;; ieee_finite, …) that the bootstrap tcc-boot2 never executes when
;; compiling float-free programs, so producing valid-but-semantically-
;; wrong P1pp here is sufficient. Kept as a named no-op so the call
;; sites stay grep-able if a future bootstrap target needs real FP.
@@ -4359,6 +4359,17 @@
(loop sto sn lg (parse-aggregate-spec ps 'union) #t))
((at-kw? ps 'enum)
(loop sto sn lg (parse-enum-spec ps) #t))
+ ;; __builtin_va_list — gcc/clang builtin type. We don't model
+ ;; it as a struct; for our P1 ABI a va_list is just a char*
+ ;; into the stack save area (cg-va-start/arg/end work over an
+ ;; 8-byte slot). Letting __builtin_va_list mean `char *` here
+ ;; lets a single header source — `typedef __builtin_va_list
+ ;; va_list;` — compile cleanly under both cc.scm and stock
+ ;; gcc/clang (where it's their native struct).
+ ((and (not b) (eq? (tok-kind t) 'IDENT)
+ (bv= (tok-value t) "__builtin_va_list"))
+ (advance ps)
+ (loop sto sn lg (%ctype 'ptr 8 8 %t-i8) #t))
((and (not b) (eq? (tok-kind t) 'IDENT)
(let ((sm (scope-lookup ps (tok-value t))))
(and sm (eq? (sym-kind sm) 'typedef))))
diff --git a/scripts/libc-flatten.sh b/scripts/libc-flatten.sh
@@ -1,5 +1,5 @@
#!/bin/sh
-## libc-flatten.sh — flatten the vendored mes-libc + lispcc-syscall.c
+## libc-flatten.sh — flatten the vendored mes-libc + boot2-syscall.c
## into a single libc.flat.c using the host preprocessor. Mirrors
## stage1-flatten.sh; runs on the host, no container — hence the
## non-`boot-` name (the convention in scripts/ is that boot-*.sh
@@ -14,7 +14,7 @@
## Stage 4 (cc.scm libc.flat.c → libc.P1pp) is a separate Makefile rule
## that reuses scripts/boot-build-cc.sh inside the per-arch container.
##
-## ARCH selects the lispcc target (aarch64/amd64/riscv64). MES_ARCH is
+## ARCH selects the boot2 target (aarch64/amd64/riscv64). MES_ARCH is
## the mes header tree we hand the host preprocessor; mes ships
## x86_64/riscv64 only, so aarch64 builds borrow riscv64's headers (the
## resulting libc.flat.c references no SYS_* / kernel-stat fields, so
@@ -121,28 +121,20 @@ apply_simple_patch \
"$STAGE/mes/ntoab.c" \
"$PATCHES/ntoab-inline-defined.before" \
"$PATCHES/ntoab-inline-defined.after"
-# Route mes's va_start/va_arg/va_end macros through cc.scm's
-# __builtin_va_* (parser-recognized in cc/cc.scm parse-builtin-va-*).
-# The original macros lower as raw C expressions; cc.scm's general
-# expression path mishandles them subtly (cc-libc/05 prints the format
-# char instead of the spilled int). The builtin path is the same one
-# tests/cc/131-vararg-mixed exercises end-to-end for printf-shaped
-# two-frame va_list forwarding.
-apply_simple_patch \
- "$STAGE/include/stdarg.h" \
- "$PATCHES/stdarg-builtin.before" \
- "$PATCHES/stdarg-builtin.after"
-
# --- (3) flatten via host preprocessor --------------------------------
HOST_CC=${HOST_CC:-cc}
-# -I order matters: include first so <signal.h>, <stdio.h> etc. hit
-# the canonical mes/include versions; arch/<…> resolves through the
-# include/arch symlink to include/linux/$MES_ARCH. Putting the per-arch
-# directory ahead of include/ makes <signal.h> resolve to the partial
-# arch-specific snippet (no stack_t typedef etc) and the build breaks.
+# -I order matters: vendor/boot2-include first so our stdarg.h shim
+# (routes va_* through __builtin_va_*; see comment in that file) wins
+# over mes's. Then $STAGE/include for everything else — <signal.h>,
+# <stdio.h>, etc. hit the canonical mes/include versions; arch/<…>
+# resolves through the include/arch symlink to include/linux/$MES_ARCH.
+# Putting the per-arch directory ahead of include/ makes <signal.h>
+# resolve to the partial arch-specific snippet (no stack_t typedef etc)
+# and the build breaks.
"$HOST_CC" -E -P \
-nostdinc \
+ -I "$ROOT/vendor/boot2-include" \
-I "$STAGE/include" \
-I "$STAGE" \
-D HAVE_CONFIG_H=0 \
diff --git a/vendor/boot2-include/stdarg.h b/vendor/boot2-include/stdarg.h
@@ -0,0 +1,39 @@
+/* boot2 stdarg.h — shadows mes/include/stdarg.h for both flatten
+ * paths (scripts/{stage1,libc}-flatten.sh both have -I on the
+ * containing dir ahead of mes's include tree). Routes va_* through
+ * __builtin_va_*, so tcc.flat.c and libc.flat.c compile cleanly
+ * under both our cc.scm (which recognizes __builtin_va_list and
+ * __builtin_va_start/arg/end) and stock gcc/clang (where they're
+ * native).
+ *
+ * Mes's stdarg.h has a similar __builtin-routed branch but only
+ * activates under __riscv. We can't set -D __riscv at flatten time
+ * without also flipping setjmp.h and tcc-internal arch logic, so we
+ * shadow the whole header instead.
+ */
+#ifndef __MES_STDARG_H
+#define __MES_STDARG_H 1
+
+typedef __builtin_va_list va_list;
+
+#define va_start(v, l) __builtin_va_start((v), (l))
+#define va_end(v) __builtin_va_end((v))
+#define va_arg(v, t) __builtin_va_arg((v), t)
+#define va_arg8(ap, type) va_arg((ap), type)
+#define va_copy(d, s) __builtin_va_copy((d), (s))
+
+/* mes/include/stdarg.h forward-declares the v* family here (instead
+ * of in <stdio.h>); tcc.c calls vsnprintf without ever including
+ * <stdio.h>, so dropping mes's stdarg.h in favor of this shim must
+ * still leak these prototypes. FILE and size_t come from a prior
+ * include in mes-libc TUs; tcc.c works because it includes
+ * <sys/types.h> for size_t and uses (FILE*) implicitly. */
+int vexec (char const *file_name, va_list ap);
+int vfprintf (FILE *stream, char const *template, va_list ap);
+int vfscanf (FILE *stream, char const *template, va_list ap);
+int vprintf (char const *format, va_list ap);
+int vsprintf (char *str, char const *format, va_list ap);
+int vsnprintf(char *str, size_t size, char const *format, va_list ap);
+int vsscanf (char const *s, char const *template, va_list ap);
+
+#endif /* __MES_STDARG_H */
diff --git a/vendor/mes-libc/include/stdarg.h b/vendor/mes-libc/include/stdarg.h
@@ -1,94 +0,0 @@
-/* -*-comment-start: "//";comment-end:""-*-
- * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
- * Copyright © 2021 W. J. van der Laan <laanwj@protonmail.com>
- * Copyright © 2023 Andrius Štikonas <andrius@stikonas.eu>
- *
- * This file is part of GNU Mes.
- *
- * GNU Mes is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or (at
- * your option) any later version.
- *
- * GNU Mes is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with GNU Mes. If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __MES_STDARG_H
-#define __MES_STDARG_H 1
-
-#if SYSTEM_LIBC
-#undef __MES_STDARG_H
-#include_next <stdarg.h>
-
-#define va_arg8(ap, type) va_arg (ap, type)
-
-#elif (__GNUC__ || __TINYC__) && __riscv
-
-// GCC on RISC-V always passes arguments in registers. Implementing
-// these macros without the use of built-ins would be very involved.
-// TINYCC tries to be GCC compatible in this case.
-
-#if __TINYC__
-// TINYCC needs some definitions in RISC-V in order to be built
-// without it's own code generation tool.
-typedef char *__builtin_va_list;
-#define __va_reg_size (__riscv_xlen >> 3)
-#define _tcc_align(addr, type) \
- (((unsigned long)addr + __alignof__(type) - 1) \
- & -(__alignof__(type)))
-#define __builtin_va_arg(ap, type) \
- (*(sizeof (type) > (2*__va_reg_size) \
- ? *(type **)((ap += __va_reg_size) - __va_reg_size) \
- : (ap = (va_list)(_tcc_align (ap, type) \
- + (sizeof (type) + __va_reg_size - 1) \
- & -__va_reg_size), \
- (type *)(ap - ((sizeof (type)+ __va_reg_size - 1) \
- & -__va_reg_size)))))
-
-#define __builtin_va_end(ap) (void)(ap)
-#if !defined (__builtin_va_copy)
-#define __builtin_va_copy(dest, src) (dest) = (src)
-#endif
-#endif // __TINYC__
-
-typedef __builtin_va_list va_list;
-
-#define va_start(v, l) __builtin_va_start (v, l)
-#define va_end(v) __builtin_va_end (v)
-#define va_arg(v, l) __builtin_va_arg (v, l)
-#define va_arg8(ap, type) va_arg (ap, type)
-#define va_copy(d, s) __builtin_va_copy (d, s)
-
-#else // ! SYSTEM_LIBC && ! __riscv
-
-#include <sys/types.h>
-
-#if __GNUC__ && __x86_64__
-#define __FOO_VARARGS 1
-#endif
-
-typedef char *va_list;
-#define va_start(ap, last) (void)((ap) = (char*)(&(last)) + sizeof (void*))
-#define va_arg(ap, type) (type)(((long*)((ap) = ((ap) + sizeof (void*))))[-1])
-#define va_align(ap, alignment) ((char*)((((unsigned long) (ap)) + (alignment) - 1) &~ ((alignment) - 1)))
-#define va_arg8(ap, type) (type)(((double*)((ap) = (va_align((ap), 8) + sizeof(double))))[-1])
-#define va_end(ap) (void)((ap) = 0)
-#define va_copy(dest, src) dest = src
-
-int vexec (char const *file_name, va_list ap);
-int vfprintf (FILE * stream, char const *template, va_list ap);
-int vfscanf (FILE * stream, char const *template, va_list ap);
-int vprintf (char const *format, va_list ap);
-int vsprintf (char *str, char const *format, va_list ap);
-int vsnprintf (char *str, size_t size, char const *format, va_list ap);
-int vsscanf (char const *s, char const *template, va_list ap);
-
-#endif // ! SYSTEM_LIBC
-
-#endif // __MES_STDARG_H
diff --git a/vendor/mes-libc/patches/stdarg-builtin.after b/vendor/mes-libc/patches/stdarg-builtin.after
@@ -1,12 +0,0 @@
-/* Routed through cc.scm's __builtin_va_* parser-recognized names so
- * va_start/va_arg/va_end go through cc/cc.scm cg-va-{start,arg,end}.
- * The original mes macros lower as raw C expressions; cc.scm's
- * general expression path mishandles them (see cc-libc/05). The
- * builtin path is exercised by tests/cc/131-vararg-mixed for the
- * printf -> vprintf -> vfprintf two-frame forwarding shape. */
-typedef char *va_list;
-#define va_start(ap, last) __builtin_va_start((ap), (last))
-#define va_arg(ap, type) __builtin_va_arg((ap), type)
-#define va_arg8(ap, type) __builtin_va_arg((ap), type)
-#define va_end(ap) __builtin_va_end((ap))
-#define va_copy(dest, src) (dest) = (src)
diff --git a/vendor/mes-libc/patches/stdarg-builtin.before b/vendor/mes-libc/patches/stdarg-builtin.before
@@ -1,7 +0,0 @@
-typedef char *va_list;
-#define va_start(ap, last) (void)((ap) = (char*)(&(last)) + sizeof (void*))
-#define va_arg(ap, type) (type)(((long*)((ap) = ((ap) + sizeof (void*))))[-1])
-#define va_align(ap, alignment) ((char*)((((unsigned long) (ap)) + (alignment) - 1) &~ ((alignment) - 1)))
-#define va_arg8(ap, type) (type)(((double*)((ap) = (va_align((ap), 8) + sizeof(double))))[-1])
-#define va_end(ap) (void)((ap) = 0)
-#define va_copy(dest, src) dest = src
