boot2

commit 5dbea4132c4faacb1c5a1056b67a75ce698c36bf
parent 0a92484ce7291fd32af9aab2e2b4a7399e57f65b
Author: Ryan Sepassi <rsepassi@gmail.com>
Date:   Thu, 30 Apr 2026 10:13:38 -0700

tcc-todo update

Diffstat:
M
docs/TCC-TODO.md
 | 
47
+++++++++++++++++++++++++++++++++++------------

1 file changed, 35 insertions(+), 12 deletions(-)
diff --git a/docs/TCC-TODO.md b/docs/TCC-TODO.md
@@ -74,11 +74,14 @@ make test SUITE=tcc-cc
 Result:
 
 ```text
-13 passed, 139 failed
+14 passed, 139 failed
 ```
 
-(152 fixtures total; the count dropped by 1 since `068-main-noret`
-was retired as part of the host-baseline cleanup.)
+(153 fixtures total. `068-main-noret` was retired earlier as part of
+the host-baseline cleanup; `134-decl-define-in-ifdef` was added as a
+regression for the `pps-cond-stack` promotion fix in cc.scm. The new
+fixture passes the cc-built tcc-boot2 path because tcc itself has no
+trouble with the shape; cc.scm couldn't compile it before the fix.)
 
 Raw run log:
 
@@ -86,6 +89,14 @@ Raw run log:
 build/aarch64/.work/tests/tcc-cc/full-run.log
 ```
 
+Most `store(...); assert fail: 0` lines are now prefixed with a
+`vfprintf: skipping second: l` line. That's mes-libc's `vfprintf`
+warning that it ignored a second `l` length-modifier in tcc's
+`%lld` format strings (vendor/mes-libc/stdio/vfprintf.c:89). The
+warning is benign noise from the cc.scm-built tcc-boot2's runtime
+libc — not from the failing fixture itself — and it appears in a
+fixture's tcc.log because we capture tcc-boot2's stderr there.
+
 Passing fixtures:
 
 ```text
@@ -102,25 +113,37 @@ Passing fixtures:
 026-sizeof-expr
 049-init-scalar-global
 072-enum-const
+134-decl-define-in-ifdef
 ```
 
 Failure groups from per-fixture `tcc.log` files:
 
 | group | count | examples |
 |------:|------:|----------|
-| plain segfault during compile/link | 58 | `006-call-no-args`, `008-pointer-deref`, `011-struct`, `125-anon-union` |
-| `store(...); assert fail: 0`, then segfault | 44 | `002-arith`, `004-inc-dec`, `020-switch`, `133-for-continue` |
-| `assert fail: vtop[-1].r < VT_CONST && vtop[0].r < VT_CONST`, then segfault | 28 | `007-call-with-args`, `013-call`, `024-globals`, `132-tentative-bss-sizing` |
-| compile succeeds, generated program exits wrong | 3 | `019-zext-narrow`, `068-main-noret`, `101-char-escapes` |
+| plain segfault during compile/link | 59 | `006-call-no-args`, `008-pointer-deref`, `011-struct`, `125-anon-union` |
+| `store(...); assert fail: 0`, then segfault | 43 | `002-arith`, `004-inc-dec`, `020-switch`, `133-for-continue` |
+| `assert fail: vtop[-1].r < VT_CONST && vtop[0].r < VT_CONST`, then segfault | 31 | `007-call-with-args`, `013-call`, `015-variadic`, `024-globals`, `076-vararg-recv` |
 | `too many field init` diagnostic | 3 | `001-kitchen-sink`, `012-struct-ptr`, `053-init-struct-pos` |
-| `__builtin_va_start` warning, then segfault | 3 | `015-variadic`, `076-vararg-recv`, `079-vararg-deep` |
+| compile succeeds, generated program exits wrong | 2 | `019-zext-narrow`, `101-char-escapes` |
 | `field expected` diagnostic | 1 | `054-init-struct-desig` |
 
-The important shape is that 137 of 140 failures happen before the
+The shape is unchanged: 137 of 139 failures happen before the
 generated fixture binary runs. The dominant problem is still the
 compiled `tcc-boot2` while it is compiling/linking C input, not the
 runtime behavior of most generated test binaries.
 
+The previous run carved out a separate "`__builtin_va_start` warning,
+then segfault" group (3 fixtures: 015-variadic, 076-vararg-recv,
+079-vararg-deep). Those have moved into the `vtop[-1].r < VT_CONST`
+cluster after the libp1pp consolidation in `cc.scm` (sub-word
+ld/st, sext/zext, lea_slot, ptr arith, struct-copy via memcpy,
+cmpset, neg/bnot/bool, switch_case): the cc.scm-built tcc-boot2 no
+longer takes the upstream warning path, so the same underlying vstack
+miscompile asserts directly. Failure counts shift slightly (58→59
+plain segfaults, 44→43 store-asserts, 28→31 vtop-asserts) for the
+same reason — it's the same compiler bug surface, regrouped, not a
+behavior regression.
+
 Working hypothesis: our compiler is miscompiling tcc itself. In this
 suite, `tcc-boot2` is a tcc binary produced by `cc.scm`; the failures
 look like that produced tcc is executing bad compiler/codegen logic and
@@ -224,9 +247,9 @@ Start with the earliest minimal failures in each dominant group:
 - `006-call-no-args`: first plain segfault with a very small source.
 - `001-kitchen-sink` or `012-struct-ptr`: first incorrect tcc parser
   diagnostics around aggregate initialization.
-- `019-zext-narrow`, `068-main-noret`, `101-char-escapes`: the only
-  current failures where `tcc-boot2` successfully emits and links a
-  binary but the binary returns the wrong status.
+- `019-zext-narrow`, `101-char-escapes`: the only current failures
+  where `tcc-boot2` successfully emits and links a binary but the
+  binary returns the wrong status.
 
 Keep using `make test SUITE=cc ARCH=aarch64 NAMES=...` as the control
 path for fixture semantics, and `make test SUITE=tcc-cc NAMES=...` as