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[aot] move method_addresses to data.rel.so section to avoid text relocations #16729

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Merged
monojenkins merged 3 commits into from
Sep 10, 2019
Merged

[aot] move method_addresses to data.rel.so section to avoid text relocations #16729

monojenkins merged 3 commits into from
Sep 10, 2019

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@lewurm
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@lewurm lewurm commented Sep 9, 2019

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 #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:

$ 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:

$ 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:

$ 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

@lewurm
Revert "[android] remove text relocations in AOT/arm32 (mono#16432)"
b3658e5 
This reverts commit b6ca76c.
@lewurm
[android] put method_addresses into .data.rel.ro section to avoid .te…
85e5204 
…xt relocations

`.text` relocations aren't allowed in Android 10 (and it doesn'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
```
@lewurm lewurm requested a review from grendello September 9, 2019 08:25
@lewurm
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lewurm commented Sep 9, 2019

@radekdoulik @grendello @jonpryor is there anyone in your team with an Android 10 device who could verify this change?

@jaykrell
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jaykrell commented Sep 9, 2019 •
edited
Loading

On Windows you just say dd imagerel foo (dd=define dword) and that gives you a 32 bit offset from the start of the image/.so so foo. It is a ubiquitous construct at runtime, used by the PE format, switch tables, etc, besides the RIP-relative instructions.
Is that possible/systems on other systems?
Also, you can do this in any section. There is no runtime relocation. It is a constant computed by the static linker. But .rdata is best.

@marek-safar
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marek-safar commented Sep 9, 2019

@monojenkins backport 2019-08

@monojenkins monojenkins mentioned this pull request Sep 9, 2019
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@lewurm
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lewurm commented Sep 9, 2019

@monojenkins build failed

grendello
grendello reviewed Sep 9, 2019
View reviewed changes
mono/mini/aot-compiler.c
#define RODATA_REL_SECT ".data.rel.ro"
#else
#define RODATA_REL_SECT ".text"
#endif
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@grendello grendello Sep 9, 2019

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Why limit this change only to Android or Linux? Wouldn't other target systems benefit from the lack of relocations in the code segment?

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@lewurm lewurm Sep 9, 2019

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On macOS the assembler bails out with unknown directive on .data.rel.ro. Maybe there is something similar available but I didn't investigate. Likewise for Windows.

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@vargaz vargaz Sep 9, 2019

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Limiting it to android limits the amount of regressions which can be caused by this change.

@lewurm
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lewurm commented Sep 9, 2019

@monojenkins squash

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lewurm commented Sep 9, 2019

@monojenkins backport 2019-06

@monojenkins monojenkins mentioned this pull request Sep 9, 2019
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@jaykrell
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jaykrell commented Sep 9, 2019

It also limits the improvements.
Executable runtime relocations are nice to avoid on all platforms.
Some others disallow them.
Non-executable runtime relocations too, as wouldn't be needed on Windows anyway, and I imagine could be avoided everywhere.

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monojenkins commented Sep 9, 2019

Cannot squash because the following required status checks are not successful:

  • "Windows x64" state is "failure"
  • "Windows x64 C++" state is "failure"
  • "Windows x64 FullAOT" state is "failure"
  • "Windows x64 FullAOT+LLVM" state is "failure"

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monojenkins commented Sep 10, 2019

Cannot squash because the following required status checks are not successful:

  • "Linux AArch64" state is "failure"

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lewurm commented Sep 10, 2019

@monojenkins build Linux AArch64

@monojenkins monojenkins merged commit e40e24b into mono:master Sep 10, 2019
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lewurm commented Sep 10, 2019

@monojenkins backport 2019-08

@monojenkins monojenkins mentioned this pull request Sep 10, 2019
Merged
monojenkins added a commit that referenced this pull request Sep 10, 2019
@monojenkins
[2019-08] [aot] move method_addresses to data.rel.so section to avoid…
40631e3 
… text relocations (#16751)

[2019-08] [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 #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
```

Backport of #16729.

/cc @lewurm
ManickaP pushed a commit to ManickaP/runtime that referenced this pull request Jan 20, 2020
@lewurm @monojenkins
[aot] move method_addresses to data.rel.so section to avoid text relo…
838d695 
…cations (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 mono/mono#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 mono/mono@e40e24b
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@vargaz vargaz vargaz approved these changes

@grendello grendello grendello approved these changes

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Relocations in .text on arm

6 participants

@lewurm @jaykrell @marek-safar @monojenkins @grendello @vargaz