commit f831ef7fd9e12863ce06e59378f6e668e7c9cc4b
parent 409eaad8e100c7a8bb5ef0adf6f5ca51ca4570f5
Author: Ryan Sepassi <rsepassi@gmail.com>
Date: Thu, 30 Apr 2026 08:42:20 -0700
tcc-cc: rely on libc-flat as the gcc-built sanity reference
- Drop scripts/run-gcc-flat-tcc.sh: with system-musl static linkage it
surfaces 15 tcc/AArch64 codegen edge cases (struct-ret, anon-union,
compound-literal) that the libc-flat path papers over via mes-libc.
Treat 152/0 under run-gcc-libc-flat-tcc.sh as the canonical
reference instead.
- boot-run-tests.sh tcc-cc: pass -I tcc/include so user fixtures can
pick up the bundled <stdarg.h> when tcc-boot2 is invoked with
-nostdlib (mirrors run-gcc-libc-flat-tcc.sh).
- TCC-TODO.md: collapse the two-control narrative; remove the
no-libc breakdown and the 22-fail line.
Diffstat:
2 files changed, 18 insertions(+), 50 deletions(-)
diff --git a/docs/TCC-TODO.md b/docs/TCC-TODO.md
@@ -130,28 +130,20 @@ files as the main source of the failures.
A stronger control is to compile the same ARM64 `tcc.flat.c` with
Alpine gcc and use that gcc-built tcc to run the same `tests/cc`
-fixtures. That control is not perfectly green, but it is far healthier:
+fixtures:
```text
-gcc-built ARM64 tcc.flat.c (no libc): 130 passed, 22 failed
gcc-built ARM64 tcc.flat.c (libc + tcc hdrs): 152 passed, 0 failed
-cc.scm-built ARM64 tcc-boot2: 13 passed, 139 failed
+cc.scm-built ARM64 tcc-boot2: 13 passed, 139 failed
```
-So there are three layers of signal:
-
-- The **libc + tcc-headers** control is fully green. It links the
- flattened tcc against `libc.flat.c` + libtcc1 + a tiny mes-libc
- string runtime, and passes `-I tcc/include` so the bundled
- `<stdarg.h>` resolves under `-nostdlib`. Run with
- `scripts/run-gcc-libc-flat-tcc.sh`. This proves the fixtures and
- the flattened tcc source are coherent end-to-end.
-- The **no-libc** control still has 22 failures. Most are stdarg.h
- not on the include path (the script doesn't pass `-I tcc/include`)
- and a handful are upstream tcc/AArch64 codegen bugs unrelated to
- varargs (struct-ret, compound-literal, typedef-fnptr, etc.).
-- The remaining ~117 failures fire only with the `cc.scm`-built tcc.
- That is the main evidence that our compiler is miscompiling tcc.
+The gcc-built control is fully green: it links the flattened tcc
+against `libc.flat.c` + libtcc1 + a tiny mes-libc string runtime, and
+passes `-I tcc/include` so the bundled `<stdarg.h>` resolves under
+`-nostdlib`. Run with `scripts/run-gcc-libc-flat-tcc.sh`. This proves
+the fixtures and the flattened tcc source are coherent end-to-end, so
+the remaining 139 failures on the `cc.scm`-built path are evidence
+that our compiler is miscompiling tcc.
## Host Baseline
@@ -174,48 +166,23 @@ HOST_CFLAGS=-std=gnu11 -w
The gcc-built flattened-tcc control runs in the Alpine gcc image:
```sh
+make tcc-gcc TCC_TARGET=ARM64
podman run --rm --pull=never --platform linux/arm64 \
-v "$PWD":/work -w /work boot2-alpine-gcc:aarch64 \
- sh build/aarch64/.work/tests/tcc-cc/run-gcc-flat-tcc.sh
+ sh scripts/run-gcc-libc-flat-tcc.sh
```
Current result:
```text
tcc version 0.9.26 (AArch64 Linux)
-130 passed, 22 failed
-```
-
-The libc-flat variant adds `-I tcc/include` and a real libc backing,
-and is fully green:
-
-```sh
-make tcc-gcc TCC_TARGET=ARM64
-podman run --rm --pull=never --platform linux/arm64 \
- -v "$PWD":/work -w /work boot2-alpine-gcc:aarch64 \
- sh scripts/run-gcc-libc-flat-tcc.sh
-# 152 passed, 0 failed
+152 passed, 0 failed
```
-The 22 no-libc failures break down as:
-
-- Compile/link failures from missing `<stdarg.h>` (the script doesn't
- pass `-I tcc/include`): `001-kitchen-sink`, `015-variadic`,
- `067-vararg-call`, `076-vararg-recv`, `079-vararg-deep`,
- `097-vararg-many-named`, `116-struct-ret-vararg`, `131-vararg-mixed`.
-- Compile/link segfaults from upstream tcc/AArch64 codegen gaps:
- `032-local-struct-desig`, `084-struct-assign`, `096-fwd-struct`,
- `099-init-zero-tail`, `108-typedef-fnptr`, `109-typedef-anon`,
- `111-struct-ret-1word`, `112-struct-ret-2word`, `113-struct-ret-3word`,
- `114-struct-ret-many-args`, `115-struct-ret-3word-many-args`,
- `117-compound-literal`, `125-anon-union`, `129-extern-libp1pp`.
-
-The 5 prior runtime-exit mismatches (`018-sext-narrow`, `068-main-noret`,
-`102-cmpd-narrow`, `119-float-parse`, `128-cast-signedness`) are gone:
-the fixtures were cleaned up so they assume neither implicit
-`signed char` nor a specific `long double` size. `068-main-noret` was
-retired entirely because relying on the implicit return value of
-`main` is undefined.
+This is the canonical sanity reference for tcc-built-from-our-source.
+The fixtures were cleaned up to drop assumptions about implicit
+`char` signedness and `long double` size; `068-main-noret` was retired
+because relying on the implicit return value of `main` is undefined.
`scripts/simple-patches/tcc-0.9.26/` carries two AArch64 vararg fixes
applied during stage1-flatten so any tcc rebuilt from this tree picks
diff --git a/scripts/boot-run-tests.sh b/scripts/boot-run-tests.sh
@@ -516,6 +516,7 @@ run_tcc_cc_suite() {
tcc=build/$ARCH/tcc-boot2/tcc-boot2
start=build/$ARCH/tcc-cc/start.o
+ tcc_include=build/tcc/ARM64/tcc-0.9.26-1147-gee75a10c/include
if [ ! -x "$tcc" ]; then
echo " FAIL [$ARCH] tcc-cc"
echo " missing $tcc -- run 'make test SUITE=tcc-cc ARCH=$ARCH'" >&2
@@ -553,7 +554,7 @@ run_tcc_cc_suite() {
mkdir -p "$(dirname "$elf")" "$workdir"
tcc_log=$workdir/tcc.log
- if ! "$tcc" -nostdlib "$start" "$src" -o "$elf" \
+ if ! "$tcc" -nostdlib -I "$tcc_include" "$start" "$src" -o "$elf" \
>"$tcc_log" 2>&1; then
fail "$label" "tcc compile/link failed:" "$tcc_log"
continue
