id = 1904
title = "Windows LTO build fails"
state = "closed"
created_at = "2023-09-23T07:33:54.701Z"
closed_at = "2023-10-06T13:29:58.398Z"
labels = ["hostos: Windows"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1904"
host-os = "Windows 11 Version 10.0.22621"
host-arch = "amd64 ucrt64"
qemu-version = "current master as of writing b55e4b9c0525560577384adfc6d30eb0daa8d7be"
guest-os = "n/a"
guest-arch = "n/a"
description = """LTO likes to delete `win32_close_exception_handler` which causes an error when linking
```
[2736/5786] Linking target qemu-system-avr.exe
FAILED: qemu-system-avr.exe
"cc" "-m64" "-mcx16" @qemu-system-avr.exe.rsp
`win32_close_exception_handler' referenced in section `.xdata' of C:\\msys64\\tmp\\cceRwR4N.ltrans59.ltrans.o: defined in discarded section `.text' of libqemuutil.a.p/util_oslib-win32.c.obj (symbol from plugin)
collect2.exe: error: ld returned 1 exit status
```"""
reproduce = """1. `./configure --enable-lto`
2. `make`"""
additional = """Looks like the offending commit is d89f30b4df13dfe389a4d6cf8a30b2f87c4c166e "win32: wrap socket close() with an exception handler".
Undoing the commit or marking the exception handler as `__attribute__ ((noinline, used))` both appear to fix the issue."""