[aot] move method_addresses to data.rel.so section to avoid text relocations (mono/mono#16729)
[aot] move method_addresses to data.rel.so section to avoid text relocations
Another revert of a revert! 🎉
After some discussions with @grendello and @radekdoulik, we came up with this solution. It's a better attempt to fix https://github.com/mono/mono/issues/16369 as it (1) works within the restrictions of Android 10 and (2) still works for armv7 AOT.
`.text` relocations aren't allowed in Android 10 (and this change shouldn't hurt on Linux).
AOT compilation:
```console
$ MONO_PATH=/Users/lewurm/Downloads/xamarin.android-oss-v10.0.99.136_Darwin-x86_64_pr_766265b9-Debug/bin/Debug/lib/xamarin.android/xbuild-frameworks/MonoAndroid/v1.0/ \
MONO_ENV_OPTIONS="" \
./sdks/out/android-cross-arm-release/bin/armv7-linux-android-mono-sgen \
--aot=keep-temps,outfile=here.dll.so,asmwriter,mtriple=armv7-linux-gnueabi,tool-prefix=/Users/lewurm/android-toolchain/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-,ld-flags= \
~/Downloads/xamarin.android-oss-v10.0.99.136_Darwin-x86_64_pr_766265b9-Debug/bin/Debug/lib/xamarin.android/xbuild-frameworks/MonoAndroid/v10.0/Mono.Android.dll
Mono Ahead of Time compiler - compiling assembly /Users/lewurm/Downloads/xamarin.android-oss-v10.0.99.136_Darwin-x86_64_pr_766265b9-Debug/bin/Debug/lib/xamarin.android/xbuild-frameworks/MonoAndroid/v10.0/Mono.Android.dll
AOTID
7DDD05DA-37E0-813A-8C27-
3E1634391BB3
Compiled: 144382/144382
Executing the native assembler: "/Users/lewurm/android-toolchain/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-as" -mfpu=vfp3 -o /var/folders/p3/5279mmgn1p575bz28j0ngfqw0000gn/T/mono_aot_550yHJ.o /var/folders/p3/5279mmgn1p575bz28j0ngfqw0000gn/T/mono_aot_550yHJ
Executing the native linker: "/Users/lewurm/android-toolchain/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-ld" -shared -o here.dll.so.tmp /var/folders/p3/5279mmgn1p575bz28j0ngfqw0000gn/T/mono_aot_550yHJ.o
Stripping the binary: "/Users/lewurm/android-toolchain/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-strip" --strip-symbol=\$a --strip-symbol=\$d here.dll.so.tmp
Retained input file.
JIT time: 15031 ms, Generation time: 7374 ms, Assembly+Link time: 75130 ms.
```
Before:
```console
$ grep -C 6 'method_addresses:' /var/folders/p3/5279mmgn1p575bz28j0ngfqw0000gn/T/mono_aot_550yHJ
.align 3
jit_code_end:
.byte 0,0,0,0
.text 1
.align 3
method_addresses:
.local method_addresses
.type method_addresses,#function
ldr pc,=.Lm_0
.ltorg
ldr pc,=.Lm_1
.ltorg
$ arm-linux-androideabi-readelf -a here.dll.so | grep -i textrel
0x00000016 (TEXTREL) 0x0
0x0000001e (FLAGS) TEXTREL
```
After switching to `.data.rel.so`:
```console
$ grep -C 6 'method_addresses:' /var/folders/p3/5279mmgn1p575bz28j0ngfqw0000gn/T/mono_aot_1YhAgn # assembly file produced by AOT compiler
jit_code_end:
.byte 0,0,0,0
.section ".data.rel.ro"
.subsection 0
.align 3
method_addresses:
.local method_addresses
.type method_addresses,#object
ldr pc,=.Lm_0
.ltorg
ldr pc,=.Lm_1
.ltorg
$ arm-linux-androideabi-readelf -a here.dll.so | grep -i textrel
$ echo $?
1
```
Commit migrated from https://github.com/mono/mono/commit/
e40e24b4cdc902c82cfe0a140cdb284611104242