Build errors while adding a new func to Region Map

[Sid Agrawal]

Hi,
I found the problem. I was missing another change in region_map_client.cc.
Adding that fixed the issue.
Diff:
https://github.com/sid-agrawal/genode/commit/e18fdadc0a92746efa0046a7f93c2525c99668e9.diff

I still have the questions of whether changing the ld file is expected?

-Sid

On Thu, Feb 3, 2022 at 6:48 PM Sid Agrawal <siagraw at cs.ubc.ca> wrote:

> Hi,
> I am using Genode with seL4 backend for my research. I am trying to add a
> new RPC method to RegionMap. It is meant as a simple exercise in
> understanding how the RPC framework in Genode works. The function name is
> "print_regions" and for now it does absolutely nothing. It takes in a void
> and returns a void. Unfortunately, I am running into some issues while
> adding this new RPC call to RM. I think I am missing something basic.
> First I ran into an issue where there was a mismatch between the ABI and
> library(3). I fixed it to the best of my ability and then got an error
> during library loading(4). Steps to reproduce and details of errors below.
>
> My diff is available here:
>
> Diff:
> https://github.com/sid-agrawal/genode/commit/26a79e7f1a77b99fb3b555198a29c638fd510bf4.diff
> HTML:
> https://github.com/sid-agrawal/genode/commit/26a79e7f1a77b99fb3b555198a29c638fd510bf4
>
> It is just upstream genode + 1 commit (my changes)
>
> My platform is Ubuntu 20.04.1 on x86-64
>
>
> To reproduce:
>
> git clone https://github.com/genodelabs/genode.git genode-question
> cd genode-question
> ./tool/ports/prepare_port sel4
> ./tool/ports/prepare_port grub2
> ./tool/create_builddir x86_64
>
> # Apply patch
> wget
> https://github.com/sid-agrawal/genode/commit/26a79e7f1a77b99fb3b555198a29c638fd510bf4.diff
>
> git apply 26a79e7f1a77b99fb3b555198a29c638fd510bf4.diff
>
> cd build/x86_64
> make run/thread KERNEL=sel4
>
>
>
>
> Here is what I did in my diff.
>
> 1. I started off by adding pure virtual func, GENODE_RPC, and an
> associated change in GENODE_RPC_INTERFACE to  Genode::Region_map.
>
> 2. Then I went on to fix the others files as the build errors popped up.
> This was basically in classes that inherited Region_Map.
>
> 3. Then I made a change to repos/base/lib/symbols/ld to work around the
> following error:
>
> Error: size of '_ZTVN6Genode17Region_map_clientE' symbol violates ld ABI
> (72 bytes in ABI, 80 bytes in library)
> make[3]: *** [/home/siagraw/genode/repos/base/mk/lib.mk:244:
> ld-sel4.lib.checked] Error 255
> make[2]: *** [var/libdeps:200: ld-sel4.lib] Error 2
>
>
> I am least sure of this change. I am unsure if this is a file I should
> even be modifying for something as simple as adding a new RPC method. But I
> did change it to get past the build error.
>
> 4. Then my "make run/thread KERNEL=sel4 " failed with the following error:
>
>   Program lib/ld/sel4/ld-sel4
> make[1]: Leaving directory '/home/siagraw/genode/build/x86_64'
> genode build completed
> using 'core-sel4.a' as 'core.a'
> using 'ld-sel4.lib.so' as 'ld.lib.so'
> /usr/local/genode/tool/21.05/bin/../lib/gcc/x86_64-pc-elf/10.3.0/../../../../x86_64-pc-elf/bin/ld:
> debug/core-sel4.a(region_map_client.o):(.data.rel.ro._ZTVN6Genode17Region_map_clientE[_ZTVN6Genode17Region_map_clientE]+0x40):
> u'
> collect2: error: ld returned 1 exit status
>     while executing
> "exec [cross_dev_prefix]g++ {*}$arch -nostdlib {*}[core_ld_opts]  -Wl,-z
> -Wl,max-page-size=0x1000  -Wl,-Ttext=$link_address -Wl,-gc-sections
>  -Wl,-nost..."
>     (procedure "build_core" line 18)
>     invoked from within
> "build_core debug/$core_obj {} [run_dir].core [core_link_address]"
>     (procedure "build_core_image" line 16)
>     invoked from within
> "build_core_image $binaries"
>     (procedure "run_boot_dir" line 19)
>     invoked from within
> "run_boot_dir $binaries"
>     (procedure "build_boot_image" line 35)
>     invoked from within
> "build_boot_image "core ld.lib.so init test-thread""
>     (file "/home/siagraw/genode/repos/base/run/thread.run" line 48)
>     invoked from within
> "source $include_name"
>     ("foreach" body line 6)
>     invoked from within
> "foreach include_name [get_cmd_arg --include ""] {
>         # first check if the include name is absolute
>         if {[string first "/" $include_name] == 0} {
>                 puts ..."
>     (file "/home/siagraw/genode/tool/run/run" line 1115)
> make: *** [Makefile:405: run/thread] Error 1
>
>
>
>
>
> I am at a loss on how to proceed from here and any help would be very
> useful. Perhaps I have missed another place where I should be adding my new
> function definition or perhaps the symbols need to be manually updated.
> As always, thanks for the help.
>
>
> Best,
> Sidhartha Agrawal
>
>
>
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