Makerules: Generate shlib.lds with -fuse-ld=bfd
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dj/TryBot-apply_patch |
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Patch applied to master at the time it was sent
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dj/TryBot-32bit |
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Build for i686
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Commit Message
lld does not dump a linker script with --verbose (it does not use a
linker script driven design and lots of linker processing is not
serializable as a linker script anyway). With the default
--with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
Just dump the linker script with -fuse-ld=bfd. lld since 15
(https://reviews.llvm.org/D124656) supports custom RELRO sections in the
GNU ld dumped linker script.
---
Makerules | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Comments
> On 6 Nov 2022, at 18:17, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>
> lld does not dump a linker script with --verbose (it does not use a
> linker script driven design and lots of linker processing is not
> serializable as a linker script anyway). With the default
> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>
> Just dump the linker script with -fuse-ld=bfd. lld since 15
> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
> GNU ld dumped linker script.
> ---
What if bfd isn't installed?
On 2022-11-06, Sam James wrote:
>
>
>> On 6 Nov 2022, at 18:17, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>
>> lld does not dump a linker script with --verbose (it does not use a
>> linker script driven design and lots of linker processing is not
>> serializable as a linker script anyway). With the default
>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>
>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>> GNU ld dumped linker script.
>> ---
>
>What if bfd isn't installed?
Then --with-default-link=yes has to be used:)
> On 6 Nov 2022, at 23:06, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>
> On 2022-11-06, Sam James wrote:
>>
>>
>>> On 6 Nov 2022, at 18:17, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>>
>>> lld does not dump a linker script with --verbose (it does not use a
>>> linker script driven design and lots of linker processing is not
>>> serializable as a linker script anyway). With the default
>>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>>
>>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>>> GNU ld dumped linker script.
>>> ---
>>
>> What if bfd isn't installed?
>
> Then --with-default-link=yes has to be used:)
Configure should check in that case.
On 2022-11-06, Sam James wrote:
>
>
>> On 6 Nov 2022, at 23:06, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>
>> On 2022-11-06, Sam James wrote:
>>>
>>>
>>>> On 6 Nov 2022, at 18:17, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>>>
>>>> lld does not dump a linker script with --verbose (it does not use a
>>>> linker script driven design and lots of linker processing is not
>>>> serializable as a linker script anyway). With the default
>>>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>>>
>>>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>>>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>>>> GNU ld dumped linker script.
>>>> ---
>>>
>>> What if bfd isn't installed?
>>
>> Then --with-default-link=yes has to be used:)
>
>Configure should check in that case.
The patch isn't worse than the current state: if ld => lld, the build
will just fail due to `test -s $@T` (the linker script is empty).
> On 6 Nov 2022, at 23:15, Fangrui Song <maskray@google.com> wrote:
>
> On 2022-11-06, Sam James wrote:
>>
>>
>>> On 6 Nov 2022, at 23:06, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>>
>>> On 2022-11-06, Sam James wrote:
>>>>
>>>>
>>>>> On 6 Nov 2022, at 18:17, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>>>>
>>>>> lld does not dump a linker script with --verbose (it does not use a
>>>>> linker script driven design and lots of linker processing is not
>>>>> serializable as a linker script anyway). With the default
>>>>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>>>>
>>>>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>>>>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>>>>> GNU ld dumped linker script.
>>>>> ---
>>>>
>>>> What if bfd isn't installed?
>>>
>>> Then --with-default-link=yes has to be used:)
>>
>> Configure should check in that case.
>
> The patch isn't worse than the current state: if ld => lld, the build
> will just fail due to `test -s $@T` (the linker script is empty).
Sure, but could you add a quick configure check while you're here?
On 2022-11-06, Sam James wrote:
>
>
>> On 6 Nov 2022, at 23:06, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>
>> On 2022-11-06, Sam James wrote:
>>>
>>>
>>>> On 6 Nov 2022, at 18:17, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>>>
>>>> lld does not dump a linker script with --verbose (it does not use a
>>>> linker script driven design and lots of linker processing is not
>>>> serializable as a linker script anyway). With the default
>>>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>>>
>>>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>>>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>>>> GNU ld dumped linker script.
>>>> ---
>>>
>>> What if bfd isn't installed?
>>
>> Then --with-default-link=yes has to be used:)
>
>Configure should check in that case.
I am unsure whether the additioinal complexity is worthwhile (and how?).
The patch is a follow-up to my comment in April:
https://sourceware.org/pipermail/libc-alpha/2022-April/138278.html
where the changed --with-default-link default required my lld build to specify --with-default-link=yes explicitly.
* Fangrui Song:
> lld does not dump a linker script with --verbose (it does not use a
> linker script driven design and lots of linker processing is not
> serializable as a linker script anyway). With the default
> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>
> Just dump the linker script with -fuse-ld=bfd. lld since 15
> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
> GNU ld dumped linker script.
> ---
> Makerules | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makerules b/Makerules
> index 09c0cf8357..2edc6ee4e1 100644
> --- a/Makerules
> +++ b/Makerules
> @@ -553,7 +553,7 @@ else
> # not for shared objects
> $(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
> $(LINK.o) -shared -Wl,-O1 \
> - -nostdlib -nostartfiles \
> + -nostdlib -nostartfiles -fuse-ld=bfd \
> $(sysdep-LDFLAGS) $(rtld-LDFLAGS) $(LDFLAGS.so) \
> -Wl,--verbose 2>/dev/null | \
> sed > $@T \
Would you please add the comment?
I'm not sure if a configure check is required. We have a path towards
removal of the custom linker script; the vfprintf refactor I posted is a
first step.
Thanks,
Florian
> On 7 Nov 2022, at 08:31, Florian Weimer via Libc-alpha <libc-alpha@sourceware.org> wrote:
>
> * Fangrui Song:
>
>> lld does not dump a linker script with --verbose (it does not use a
>> linker script driven design and lots of linker processing is not
>> serializable as a linker script anyway). With the default
>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>
>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>> GNU ld dumped linker script.
>> ---
>> Makerules | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/Makerules b/Makerules
>> index 09c0cf8357..2edc6ee4e1 100644
>> --- a/Makerules
>> +++ b/Makerules
>> @@ -553,7 +553,7 @@ else
>> # not for shared objects
>> $(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
>> $(LINK.o) -shared -Wl,-O1 \
>> - -nostdlib -nostartfiles \
>> + -nostdlib -nostartfiles -fuse-ld=bfd \
>> $(sysdep-LDFLAGS) $(rtld-LDFLAGS) $(LDFLAGS.so) \
>> -Wl,--verbose 2>/dev/null | \
>> sed > $@T \
>
> Would you please add the comment?
>
> I'm not sure if a configure check is required. We have a path towards
> removal of the custom linker script; the vfprintf refactor I posted is a
> first step.
>
That works for me.
On 2022-11-08, Sam James wrote:
>
>
>> On 7 Nov 2022, at 08:31, Florian Weimer via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>
>> * Fangrui Song:
>>
>>> lld does not dump a linker script with --verbose (it does not use a
>>> linker script driven design and lots of linker processing is not
>>> serializable as a linker script anyway). With the default
>>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>>
>>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>>> GNU ld dumped linker script.
>>> ---
>>> Makerules | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/Makerules b/Makerules
>>> index 09c0cf8357..2edc6ee4e1 100644
>>> --- a/Makerules
>>> +++ b/Makerules
>>> @@ -553,7 +553,7 @@ else
>>> # not for shared objects
>>> $(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
>>> $(LINK.o) -shared -Wl,-O1 \
>>> - -nostdlib -nostartfiles \
>>> + -nostdlib -nostartfiles -fuse-ld=bfd \
>>> $(sysdep-LDFLAGS) $(rtld-LDFLAGS) $(LDFLAGS.so) \
>>> -Wl,--verbose 2>/dev/null | \
>>> sed > $@T \
>>
>> Would you please add the comment?
>>
>> I'm not sure if a configure check is required. We have a path towards
>> removal of the custom linker script; the vfprintf refactor I posted is a
>> first step.
>>
>
>That works for me.
>
>
Added comments...
From 00ee52ee0753a8d849c23d4e051f10aa8a4e2074 Mon Sep 17 00:00:00 2001
From: Fangrui Song <maskray@google.com>
Date: Mon, 7 Nov 2022 16:21:13 -0800
Subject: [PATCH] Makerules: Generate shlib.lds with -fuse-ld=bfd
lld does not dump a linker script with --verbose (it does not use a
linker script driven design and lots of linker processing is not
serializable as a linker script anyway). With the default
--with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
Just dump the linker script with -fuse-ld=bfd. lld since 15
(https://reviews.llvm.org/D124656) supports custom RELRO sections in the
GNU ld dumped linker script.
---
Makerules | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Makerules b/Makerules
index 09c0cf8357..ed6873a1a8 100644
--- a/Makerules
+++ b/Makerules
@@ -546,14 +546,16 @@ endef
ifeq (yes,$(use-default-link))
# If the linker is good enough, we can let it use its default linker script.
+# In the long term the custom linker script will be removed.
shlib-lds =
shlib-lds-flags =
else
# binutils only position loadable notes into the first page for binaries,
# not for shared objects
+# lld --verbose does not dump a linker script. Use -fuse-ld=bfd.
$(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
$(LINK.o) -shared -Wl,-O1 \
- -nostdlib -nostartfiles \
+ -nostdlib -nostartfiles -fuse-ld=bfd \
$(sysdep-LDFLAGS) $(rtld-LDFLAGS) $(LDFLAGS.so) \
-Wl,--verbose 2>/dev/null | \
sed > $@T \
> On 8 Nov 2022, at 00:22, Fangrui Song via Libc-alpha <libc-alpha@sourceware.org> wrote:
>
> On 2022-11-08, Sam James wrote:
>>
>>
>>> On 7 Nov 2022, at 08:31, Florian Weimer via Libc-alpha <libc-alpha@sourceware.org> wrote:
>>>
>>> * Fangrui Song:
>>>
>>>> lld does not dump a linker script with --verbose (it does not use a
>>>> linker script driven design and lots of linker processing is not
>>>> serializable as a linker script anyway). With the default
>>>> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>>>>
>>>> Just dump the linker script with -fuse-ld=bfd. lld since 15
>>>> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
>>>> GNU ld dumped linker script.
>>>> ---
>>>> Makerules | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/Makerules b/Makerules
>>>> index 09c0cf8357..2edc6ee4e1 100644
>>>> --- a/Makerules
>>>> +++ b/Makerules
>>>> @@ -553,7 +553,7 @@ else
>>>> # not for shared objects
>>>> $(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
>>>> $(LINK.o) -shared -Wl,-O1 \
>>>> - -nostdlib -nostartfiles \
>>>> + -nostdlib -nostartfiles -fuse-ld=bfd \
>>>> $(sysdep-LDFLAGS) $(rtld-LDFLAGS) $(LDFLAGS.so) \
>>>> -Wl,--verbose 2>/dev/null | \
>>>> sed > $@T \
>>>
>>> Would you please add the comment?
>>>
>>> I'm not sure if a configure check is required. We have a path towards
>>> removal of the custom linker script; the vfprintf refactor I posted is a
>>> first step.
>>>
>>
>> That works for me.
>>
>>
>
> Added comments...
>
>
> From 00ee52ee0753a8d849c23d4e051f10aa8a4e2074 Mon Sep 17 00:00:00 2001
> From: Fangrui Song <maskray@google.com>
> Date: Mon, 7 Nov 2022 16:21:13 -0800
> Subject: [PATCH] Makerules: Generate shlib.lds with -fuse-ld=bfd
>
> lld does not dump a linker script with --verbose (it does not use a
> linker script driven design and lots of linker processing is not
> serializable as a linker script anyway). With the default
> --with-default-link=no build, $@T is empty and makes `test -s $@T` fail.
>
> Just dump the linker script with -fuse-ld=bfd. lld since 15
> (https://reviews.llvm.org/D124656) supports custom RELRO sections in the
> GNU ld dumped linker script.
> ---
Thanks!
Reviewed-by: Sam James <sam@gentoo.org <mailto:sam@gentoo.org>>
@@ -553,7 +553,7 @@ else
# not for shared objects
$(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
$(LINK.o) -shared -Wl,-O1 \
- -nostdlib -nostartfiles \
+ -nostdlib -nostartfiles -fuse-ld=bfd \
$(sysdep-LDFLAGS) $(rtld-LDFLAGS) $(LDFLAGS.so) \
-Wl,--verbose 2>/dev/null | \
sed > $@T \