boot2

commit 79c5cce3f31c1bb066907dc8c456db129d5922b0
parent 539aef860248022becef03c2f96222e0630832b6
Author: Ryan Sepassi <rsepassi@gmail.com>
Date:   Mon,  4 May 2026 16:24:17 -0700

boot4: simplify struct timespec in alltypes.h to silence tcc warning

tcc 0.9.26 emits "will touch memory past end of the struct (internal
limitation)" for any struct ending in a zero-width bitfield. musl wraps
tv_nsec in two such bitfields to handle 32-bit-time_t arches:

  struct timespec { time_t tv_sec;
    int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER==4321);
    long tv_nsec;
    int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER!=4321);
  };

On all three boot4 arches sizeof(time_t)==sizeof(long)==8, so both
bitfields are 0 width and the layout matches the simple two-field form.
The leading bitfield does not warn (a sibling follows); the trailing
one fired 387 times per build.

musl-vendor.sh now post-processes the mkalltypes output to substitute
the simple form. boot4 aarch64 build is now warning-free; libc.a drops
4 bytes (presumably tcc bitfield metadata in the archive); hello still
links, runs, and produces identical output.

Diffstat:
M
scripts/musl-vendor.sh
 | 
25
++++++++++++++++++++++++-
M
vendor/upstream/musl-1.2.5-generated/aarch64/alltypes.h
 | 
2
+-
M
vendor/upstream/musl-1.2.5-generated/riscv64/alltypes.h
 | 
2
+-
M
vendor/upstream/musl-1.2.5-generated/x86_64/alltypes.h
 | 
2
+-

4 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/scripts/musl-vendor.sh b/scripts/musl-vendor.sh
@@ -131,10 +131,33 @@ rm -rf "$ROOT/$GENERATED"
 for MARCH in aarch64 x86_64 riscv64; do
     out=$ROOT/$GENERATED/$MARCH
     mkdir -p "$out"
+    # Post-process: simplify struct timespec to drop the trailing
+    # zero-width bitfield (see comment above the awk pipeline below).
     awk -f "$ROOT/$MKALLTYPES_AWK" \
         "$POST/musl-1.2.5/arch/$MARCH/bits/alltypes.h.in" \
         "$POST/musl-1.2.5/include/alltypes.h.in" \
-        > "$out/alltypes.h"
+        | awk '
+            /^struct timespec \{.*tv_nsec/ {
+                print "struct timespec { time_t tv_sec; long tv_nsec; };"
+                next
+            }
+            { print }
+        ' > "$out/alltypes.h"
+    # Why the post-process: tcc 0.9.26 emits "will touch memory past
+    # end of the struct (internal limitation)" for any struct ending
+    # in a zero-width bitfield. The musl alltypes.h definition wraps
+    # tv_nsec in two bitfield-padding tricks for 32-bit-time_t arches:
+    #
+    #   struct timespec { time_t tv_sec;
+    #     int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER==4321);
+    #     long tv_nsec;
+    #     int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER!=4321);
+    #   };
+    #
+    # On all three boot4 arches sizeof(time_t)==sizeof(long)==8, so
+    # both bitfields are 0 width and the layout is identical to the
+    # simple two-field form. The leading bitfield does not warn (a
+    # sibling follows); the trailing one does, 387 times per build.
     cp "$POST/musl-1.2.5/arch/$MARCH/bits/syscall.h.in" "$out/syscall.h"
     awk 'sub(/__NR_/, "SYS_") { print }' \
         < "$POST/musl-1.2.5/arch/$MARCH/bits/syscall.h.in" \
diff --git a/vendor/upstream/musl-1.2.5-generated/aarch64/alltypes.h b/vendor/upstream/musl-1.2.5-generated/aarch64/alltypes.h
@@ -234,7 +234,7 @@ struct timeval { time_t tv_sec; suseconds_t tv_usec; };
 #endif
 
 #if defined(__NEED_struct_timespec) && !defined(__DEFINED_struct_timespec)
-struct timespec { time_t tv_sec; int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER==4321); long tv_nsec; int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER!=4321); };
+struct timespec { time_t tv_sec; long tv_nsec; };
 #define __DEFINED_struct_timespec
 #endif
 
diff --git a/vendor/upstream/musl-1.2.5-generated/riscv64/alltypes.h b/vendor/upstream/musl-1.2.5-generated/riscv64/alltypes.h
@@ -224,7 +224,7 @@ struct timeval { time_t tv_sec; suseconds_t tv_usec; };
 #endif
 
 #if defined(__NEED_struct_timespec) && !defined(__DEFINED_struct_timespec)
-struct timespec { time_t tv_sec; int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER==4321); long tv_nsec; int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER!=4321); };
+struct timespec { time_t tv_sec; long tv_nsec; };
 #define __DEFINED_struct_timespec
 #endif
 
diff --git a/vendor/upstream/musl-1.2.5-generated/x86_64/alltypes.h b/vendor/upstream/musl-1.2.5-generated/x86_64/alltypes.h
@@ -226,7 +226,7 @@ struct timeval { time_t tv_sec; suseconds_t tv_usec; };
 #endif
 
 #if defined(__NEED_struct_timespec) && !defined(__DEFINED_struct_timespec)
-struct timespec { time_t tv_sec; int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER==4321); long tv_nsec; int :8*(sizeof(time_t)-sizeof(long))*(__BYTE_ORDER!=4321); };
+struct timespec { time_t tv_sec; long tv_nsec; };
 #define __DEFINED_struct_timespec
 #endif