Hi Song,
This is a long time history bug. the '-DPIC' just add to compile option when
Nasm is enabled, the bug can simple fix with below patch (NO TEST since I
haven't ARM environment).
After patch, the user may acivate these compile option with ENABLE_PIC=ON
Could the x265 team please help verify patch?
Regards,
Min Chen
diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index 13e4750de..80f8e59a9 100755
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -266,6 +266,9 @@ if(GCC)
add_definitions(-DHAVE_NEON)
endif()
endif()
+ if(ENABLE_PIC)
+ list(APPEND ARM_ARGS -DPIC)
+ endif()
add_definitions(${ARM_ARGS})
if(FPROFILE_GENERATE)
if(INTEL_CXX)
2022-10-18 14:37:10，"Fangrui Song" <mask...@google.com>
On Thu, Oct 6, 2022 at 1:39 AM chen <chenm...@163.com> wrote:
Hi Song,
I means the current tree support these adrp+add mode with compile option -DPIC,
so we need not patch the code.
Regards,
Min Chen
Hi Min, IIUC -DPIC is only defined for x86-64
(source/cmake/CMakeASM_NASMInformation.cmake).
AArch64 does not get -DPIC.
2022-10-06 06:42:33，"Fangrui Song" <mask...@google.com>
Hi Min, sorry but I just saw your question. I do not understand the request.
adrp+add is just strictly superior to ldr (which uses a constant pool and does
not decrease code size) and avoids text relocations (which are prohibited in
many systems). `ldr \rd, =\val+\offset` should just be removed.
adrp+add also works on Mach-O systems as well.
At 2022-09-24 15:21:35, "Fangrui Song" <mask...@google.com> wrote:
>Ping. The breaks lld build and some binutils configurating defaulting
>to disallow text relocations.
>
>On 2022-08-29, Fangrui Song wrote:
>>On 2022-08-29, Fangrui Song wrote:
>>>On 2022-08-30, chen wrote:
>>>>Hi Song,
>>>>
>>>>
>>>>Thank you for your patch.
>>>>
>>>>
>>>>However, syntax of ':lo12:' depends on compiler, so more general LDR is
>>>>better in here.
>>>>
>>>>
>>>>Regards,
>>>>Min Chen
>>>
>>>:lo12: is standard aarch64 assembly syntax.
>>>Which aarch64 compiler supported by x265 does not support :lo12:?
>>
>>Note that LDR has another problem that it produced an absolute relocation
>>R_AARCH64_ABS64. It will trigger an error
>>when text relocations are disabled (default in ld.lld. See
>>https://maskray.me/blog/2020-12-19-lld-and-gnu-linker-incompatibilities#:~:text=Text%20relocations)
>>
>>```
>>% : && /usr/bin/c++ -fPIC -O3 -DNDEBUG -Wl,-Bsymbolic,-znoexecstack -shared
>>...
>>ld: error: relocation R_AARCH64_ABS64 cannot be used against local
>>symbol; recompile with -fPIC
>>>>>defined in sad-a.S.o
>>>>>>>> referenced by sad-a.S.o:(.text+0x9B00)
>>```
>>
>>adrp+add work fine.
>>
>>(I am a maintainer of lld/ELF.)
>>
>>>>At 2022-08-30 02:33:37, "Fangrui Song" <mask...@google.com> wrote:
>>>>>The ldr pseudo-instruction uses a literal pool, which is less efficient
>>>>>and does not decrease the code size.
>>>>>---
>>>>>source/common/aarch64/asm.S | 4 +---
>>>>>1 file changed, 1 insertion(+), 3 deletions(-)
>>>>>
>>>>>diff --git a/source/common/aarch64/asm.S b/source/common/aarch64/asm.S
>>>>>index 399c37cf2..2506f50aa 100644
>>>>>--- a/source/common/aarch64/asm.S
>>>>>+++ b/source/common/aarch64/asm.S
>>>>>@@ -130,11 +130,9 @@ ELF .size \name, . - \name
>>>>> adrp \rd, \val+(\offset)
>>>>> add \rd, \rd, :lo12:\val+(\offset)
>>>>> .endif
>>>>>-#elif defined(PIC)
>>>>>+#else
>>>>> adrp \rd, \val+(\offset)
>>>>> add \rd, \rd, :lo12:\val+(\offset)
>>>>>-#else
>>>>>- ldr \rd, =\val+\offset
>>>>>#endif
>>>>>.endm
>>>>>
>>>>>--
>>>>>2.37.2.672.g94769d06f0-goog
>>>>>
>>>>>_______________________________________________
>>>>>x265-devel mailing list
>>>>>x265-devel@videolan.org
>>>>>https://mailman.videolan.org/listinfo/x265-devel
>>>
>>>>_______________________________________________
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>>>>x265-devel@videolan.org
>>>>https://mailman.videolan.org/listinfo/x265-devel
>>>
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