Re: [PATCH 3/7] scripts/nsis.py: Automatically package required DLLs of QEMU executables

[Stefan Weil via <qemu-devel@nongnu.org>]

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Am 26.02.24 um 05:35 schrieb Bin Meng:

> On Mon, Feb 26, 2024 at 1:37 AM Stefan Weil<sw@weilnetz.de>  wrote:
>> Am 10.09.22 um 02:37 schrieb Bin Meng:
>>> On Sat, Sep 10, 2022 at 12:49 AM Mark Cave-Ayland
>>> <mark.cave-ayland@ilande.co.uk>  wrote:
>>>> On 08/09/2022 14:28, Bin Meng wrote:
>>>>
>>>>> From: Bin Meng<bin.meng@windriver.com>
>>>>>
>>>>> At present packaging the required DLLs of QEMU executables is a
>>>>> manual process, and error prone.
>>>>>
>>>>> Actually build/config-host.mak contains a GLIB_BINDIR variable
>>>>> which is the directory where glib and other DLLs reside. This
>>>>> works for both Windows native build and cross-build on Linux.
>>>>> We can use it as the search directory for DLLs and automate
>>>>> the whole DLL packaging process.
>>>>>
>>>>> Signed-off-by: Bin Meng<bin.meng@windriver.com>
>>>>> ---
>>>>>
>>>>>     meson.build     |  1 +
>>>>>     scripts/nsis.py | 46 ++++++++++++++++++++++++++++++++++++++++++----
>>>>>     2 files changed, 43 insertions(+), 4 deletions(-)
>>>>>
>> [...]>>> diff --git a/scripts/nsis.py b/scripts/nsis.py
>>>>> index baa6ef9594..03ed7608a2 100644
>>>>> --- a/scripts/nsis.py
>>>>> +++ b/scripts/nsis.py
>>>>> @@ -18,12 +18,36 @@ def signcode(path):
>>>>>             return
>>>>>         subprocess.run([cmd, path])
>>>>>
>>>>> +def find_deps(exe_or_dll, search_path, analyzed_deps):
>>>>> +    deps = [exe_or_dll]
>>>>> +    output = subprocess.check_output(["objdump", "-p", exe_or_dll], text=True)
>> This fails on non x86 hosts where objdump does not know how to handle a
>> Windows x86_64 exe file.
> Does this command work in the MSYS2 environment on Windows Arm?


I don't know and cannot test that, because I don't run Windows on ARM.

>>>>> +    output = output.split("\n")
>>>>> +    for line in output:
>>>>> +        if not line.startswith("\tDLL Name: "):
>>>>> +            continue
>>>>> +
>>>>> +        dep = line.split("DLL Name: ")[1].strip()
>>>>> +        if dep in analyzed_deps:
>>>>> +            continue
>>>>> +
>>>>> +        dll = os.path.join(search_path, dep)
>>>>> +        if not os.path.exists(dll):
>>>>> +            # assume it's a Windows provided dll, skip it
>>>>> +            continue
>>>>> +
>>>>> +        analyzed_deps.add(dep)
>>>>> +        # locate the dll dependencies recursively
>>>>> +        rdeps = find_deps(dll, search_path, analyzed_deps)
>>>>> +        deps.extend(rdeps)
>>>>> +
>>>>> +    return deps
>> [...]
>>>> FWIW I wrote a similar script a while back to help package a custom Windows build for
>>>> a client, however I used ldd instead of objdump since it provided the full paths for
>>>> DLLs installed in the msys2/mingw-w64 environment via pacman which were outside the
>>>> QEMU build tree.
>>>>
>>> Yep, ldd also works, but only on Windows native build. objdump can
>>> work on both Windows native and Linux cross builds.
>>
>> objdump fails on Linux cross builds on any non x86 host, because objdump
>> typically only supports the native host architecture.
>>
>> Therefore I get an error on an ARM64 host (podman on Mac M1):
>>
>>           objdump: /tmp/tmpvae5u0qm/qemu/qemu-system-aarch64.exe: file
>> format not recognized
>>
>> I could use x86_64-w64-mingw32-objdump to fix the cross builds, but then
>> native builds might fail because they don't have x86_64-w64-mingw32-objdump.
>>
>> Is there a simple way how we can get the information here whether
>> objdump requires a cross build prefix?
> For QEMU Windows, I believe the only supported architecture is x86_64,
> correct? Do we want to support (cross) building QEMU for Windows Arm?


Yes, I think we only support QEMU on Windows x86_64. I also don't know 
anyone who has tried building for Windows ARM. And up to now I also was 
never asked for that, so obviously there is still no need for it.


> Based on your observation, objdump on Linux cross builds on any x86
> host works, but not on non x86 host.
> Maybe it's a hint to ask for binutils guys to include the PE format
> support for objdump Arm by default.


I am afraid that we'll have to find a solution on the QEMU side, not 
wait until all binutils support the PE format for x86_64 (which would 
make the binaries or the library much larger).

Stefan


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