Re: [Tarantool-patches] [PATCH luajit v4 5/8] OSX/ARM64: Disable unwind info.

Re: [Tarantool-patches] [PATCH luajit v4 5/8] OSX/ARM64: Disable unwind info.

[Sergey Kaplun via Tarantool-patches]

Hi, Maksim!
Thanks for the patch!

LGTM, with a single nit regarding the commit message.

On 28.10.22, Maksim Kokryashkin wrote:
> From: Mike Pall <mike>
> 
> See #698.
> 
> (cherry picked from commit 78350a2565e1cf1102bcd25be406f02953d4dd3b)
> 
> External unwinding support is already disabled for OSX on ARM64

Typo: s/on ARM64 platform/on the ARM64 platform/

> platform so there is no point in generation of incorrect unwind
> info for it. This patch disables that generation for the commit
> history match, and it will be re-enabled in the next commit,
> which contains the fix for the issue.
> 
> Maxim Kokryashkin:
> * added the description for the problem
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
>  src/vm_arm64.dasc | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
> index ad57bca3..ccfa72bd 100644
> --- a/src/vm_arm64.dasc
> +++ b/src/vm_arm64.dasc

<snipped>

> -- 
> 2.37.0 (Apple Git-136)
> 

-- 
Best regards,
Sergey Kaplun

Re: [Tarantool-patches] [PATCH luajit v4 5/8] OSX/ARM64: Disable unwind info.

[Maxim Kokryashkin via Tarantool-patches]

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Hi!
  
>Четверг, 24 ноября 2022, 14:44 +03:00 от Sergey Kaplun <skaplun@tarantool.org>:
> 
>Hi, Maksim!
>Thanks for the patch!
>
>LGTM, with a single nit regarding the commit message.
>
>On 28.10.22, Maksim Kokryashkin wrote:
>> From: Mike Pall <mike>
>>
>> See #698.
>>
>> (cherry picked from commit 78350a2565e1cf1102bcd25be406f02953d4dd3b)
>>
>> External unwinding support is already disabled for OSX on ARM64
>
>Typo: s/on ARM64 platform/on the ARM64 platform/
Fixed.
> 
--
Best regards,
Maxim Kokryashkin

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Re: [Tarantool-patches] [PATCH luajit v4 5/8] OSX/ARM64: Disable unwind info.

[sergos via Tarantool-patches]

Hi!

Thanks for the patch!

LGTM.

Sergos


> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> From: Mike Pall <mike>
> 
> See #698.
> 
> (cherry picked from commit 78350a2565e1cf1102bcd25be406f02953d4dd3b)
> 
> External unwinding support is already disabled for OSX on ARM64
> platform so there is no point in generation of incorrect unwind
> info for it. This patch disables that generation for the commit
> history match, and it will be re-enabled in the next commit,
> which contains the fix for the issue.
> 
> Maxim Kokryashkin:
> * added the description for the problem
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
> src/vm_arm64.dasc | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
> index ad57bca3..ccfa72bd 100644
> --- a/src/vm_arm64.dasc
> +++ b/src/vm_arm64.dasc
> @@ -3990,7 +3990,8 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	".LEFDE3:\n\n", (int)ctx->codesz - fcofs);
> #endif
>     break;
> -#if !LJ_NO_UNWIND
> +    /* Disabled until someone finds a fix. See #698. */
> +#if !LJ_NO_UNWIND && 0
>   case BUILD_machasm: {
> #if LJ_HASFFI
>     int fcsize = 0;
> -- 
> 2.37.0 (Apple Git-136)
> 

Re: [Tarantool-patches] [PATCH luajit v4 6/8] BSD: Fix build with BSD grep.

[Sergey Kaplun via Tarantool-patches]

Hi, Maksim!

Thanks for the patch!

LGTM, with a single nit below.

On 28.10.22, Maksim Kokryashkin wrote:
> From: Mike Pall <mike>
> 
> Thanks to carlocab.
> 
> (cherry picked from commit b9d523965b3f55b19345a1ed1ebc92e431747ce1)
> 
> The `-U` option makes grep process the temporary binary file as
> a binary instead of text, meaning that its contents are passed

I suggest to clarify this part like the following:
| instead of as ASCII text with `-a` option set

> to grep verbatim.
> 
> Maxim Kokryashkin:
> * added the description for the problem and updated the CMake
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
>  cmake/SetTargetFlags.cmake | 2 +-
>  src/Makefile.original      | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index d99e1f9a..943a3152 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake

<snipped>

> diff --git a/src/Makefile.original b/src/Makefile.original
> index 5826a56a..4d7cda3e 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original

<snipped>

> -- 
> 2.37.0 (Apple Git-136)
> 

-- 
Best regards,
Sergey Kaplun

Re: [Tarantool-patches] [PATCH luajit v4 6/8] BSD: Fix build with BSD grep.

[Maxim Kokryashkin via Tarantool-patches]

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Hi!
Thanks for the review!
  
>Четверг, 24 ноября 2022, 14:52 +03:00 от Sergey Kaplun <skaplun@tarantool.org>:
> 
>Hi, Maksim!
>
>Thanks for the patch!
>
>LGTM, with a single nit below.
>
>On 28.10.22, Maksim Kokryashkin wrote:
>> From: Mike Pall <mike>
>>
>> Thanks to carlocab.
>>
>> (cherry picked from commit b9d523965b3f55b19345a1ed1ebc92e431747ce1)
>>
>> The `-U` option makes grep process the temporary binary file as
>> a binary instead of text, meaning that its contents are passed
>
>I suggest to clarify this part like the following:
>| instead of as ASCII text with `-a` option set
Fixed.
>
>> to grep verbatim.
>>
>> Maxim Kokryashkin:
>> * added the description for the problem and updated the CMake
>>
>> Needed for tarantool/tarantool#6096
>> Part of tarantool/tarantool#7230
>> ---
>> cmake/SetTargetFlags.cmake | 2 +-
>> src/Makefile.original | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
>> index d99e1f9a..943a3152 100644
>> --- a/cmake/SetTargetFlags.cmake
>> +++ b/cmake/SetTargetFlags.cmake
>
><snipped>
>
>> diff --git a/src/Makefile.original b/src/Makefile.original
>> index 5826a56a..4d7cda3e 100644
>> --- a/src/Makefile.original
>> +++ b/src/Makefile.original
>
><snipped>
>
>> --
>> 2.37.0 (Apple Git-136)
>>
>
>--
>Best regards,
>Sergey Kaplun
--
Best regards,
Maxim Kokryashkin
 

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Re: [Tarantool-patches] [PATCH luajit v4 6/8] BSD: Fix build with BSD grep.

[sergos via Tarantool-patches]

Hi!

Thanks for the patch!

LGTM.

Sergos

> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> From: Mike Pall <mike>
> 
> Thanks to carlocab.
> 
> (cherry picked from commit b9d523965b3f55b19345a1ed1ebc92e431747ce1)
> 
> The `-U` option makes grep process the temporary binary file as
> a binary instead of text, meaning that its contents are passed
> to grep verbatim.
> 
> Maxim Kokryashkin:
> * added the description for the problem and updated the CMake
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
> cmake/SetTargetFlags.cmake | 2 +-
> src/Makefile.original      | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index d99e1f9a..943a3152 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake
> @@ -23,7 +23,7 @@ else()
>   string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
>   if(UNWIND_POS EQUAL -1)
>     execute_process(
> -      COMMAND bash -c "exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | ${CMAKE_C_COMPILER} -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o"
> +      COMMAND bash -c "exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | ${CMAKE_C_COMPILER} -c -x c - -o tmpunwind.o && grep -qU -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o"
>       WORKING_DIRECTORY ${LUAJIT_SOURCE_DIR}
>       OUTPUT_VARIABLE TESTUNWIND
>       RESULT_VARIABLE TESTUNWIND_RC
> diff --git a/src/Makefile.original b/src/Makefile.original
> index 5826a56a..4d7cda3e 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original
> @@ -344,7 +344,7 @@ ifeq (iOS,$(TARGET_SYS))
> else
>   ifeq (,$(findstring LJ_NO_UNWIND 1,$(TARGET_TESTARCH)))
>     # Find out whether the target toolchain always generates unwind tables.
> -    TARGET_TESTUNWIND=$(shell exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | $(TARGET_CC) -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o)
> +    TARGET_TESTUNWIND=$(shell exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | $(TARGET_CC) -c -x c - -o tmpunwind.o && grep -qU -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o)
>     ifneq (,$(findstring E,$(TARGET_TESTUNWIND)))
>       TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
>     endif
> -- 
> 2.37.0 (Apple Git-136)
> 

Re: [Tarantool-patches] [PATCH luajit v4 7/8] Fix build with busybox grep.

[Sergey Kaplun via Tarantool-patches]

Hi, Maksim!
Thanks for the patch!

LGTM, with a single nit below.

On 28.10.22, Maksim Kokryashkin wrote:
> From: Mike Pall <mike>
> 
> Reported by ymph.
> 
> (cherry picked from commit 66563bdab0c7acf3cd61dc6cfcca36275951d084)
> 
> Busybox implementation of grep doesn't have the `-U` option, but it
> has the option to treat the binary as a text file, so that case is

Minor: the `-a` option

> provided as an alternative.
> 
> Maxim Kokryashkin:
> * added the description for the problem and updated the CMake
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
>  cmake/SetTargetFlags.cmake | 2 +-
>  src/Makefile.original      | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index 943a3152..8abb6288 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake

<snipped>

> diff --git a/src/Makefile.original b/src/Makefile.original
> index 4d7cda3e..2d014e43 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original

<snipped>

> -- 
> 2.37.0 (Apple Git-136)
> 

-- 
Best regards,
Sergey Kaplun

Re: [Tarantool-patches] [PATCH luajit v4 7/8] Fix build with busybox grep.

[Maxim Kokryashkin via Tarantool-patches]

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Hi!
Thanks for the review!
 
 
 
  
>Четверг, 24 ноября 2022, 15:00 +03:00 от Sergey Kaplun <skaplun@tarantool.org>:
> 
>Hi, Maksim!
>Thanks for the patch!
>
>LGTM, with a single nit below.
>
>On 28.10.22, Maksim Kokryashkin wrote:
>> From: Mike Pall <mike>
>>
>> Reported by ymph.
>>
>> (cherry picked from commit 66563bdab0c7acf3cd61dc6cfcca36275951d084)
>>
>> Busybox implementation of grep doesn't have the `-U` option, but it
>> has the option to treat the binary as a text file, so that case is
>
>Minor: the `-a` option
Fixed.
>
>> provided as an alternative.
>>
>> Maxim Kokryashkin:
>> * added the description for the problem and updated the CMake
>>
>> Needed for tarantool/tarantool#6096
>> Part of tarantool/tarantool#7230
>> ---
>> cmake/SetTargetFlags.cmake | 2 +-
>> src/Makefile.original | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
>> index 943a3152..8abb6288 100644
>> --- a/cmake/SetTargetFlags.cmake
>> +++ b/cmake/SetTargetFlags.cmake
>
><snipped>
>
>> diff --git a/src/Makefile.original b/src/Makefile.original
>> index 4d7cda3e..2d014e43 100644
>> --- a/src/Makefile.original
>> +++ b/src/Makefile.original
>
><snipped>
>
>> --
>> 2.37.0 (Apple Git-136)
>>
>
>--
>Best regards,
>Sergey Kaplun
--
Best regards,
Maxim Kokryashkin
 

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Re: [Tarantool-patches] [PATCH luajit v4 7/8] Fix build with busybox grep.

[sergos via Tarantool-patches]

Hi!

Thanks for the patch!

LGTM

Sergos


> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> From: Mike Pall <mike>
> 
> Reported by ymph.
> 
> (cherry picked from commit 66563bdab0c7acf3cd61dc6cfcca36275951d084)
> 
> Busybox implementation of grep doesn't have the `-U` option, but it
> has the option to treat the binary as a text file, so that case is
> provided as an alternative.
> 
> Maxim Kokryashkin:
> * added the description for the problem and updated the CMake
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
> cmake/SetTargetFlags.cmake | 2 +-
> src/Makefile.original      | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index 943a3152..8abb6288 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake
> @@ -23,7 +23,7 @@ else()
>   string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
>   if(UNWIND_POS EQUAL -1)
>     execute_process(
> -      COMMAND bash -c "exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | ${CMAKE_C_COMPILER} -c -x c - -o tmpunwind.o && grep -qU -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o"
> +      COMMAND bash -c "exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | ${CMAKE_C_COMPILER} -c -x c - -o tmpunwind.o && { grep -qa -e eh_frame -e __unwind_info tmpunwind.o || grep -qU -e eh_frame -e __unwind_info tmpunwind.o; } && echo E; rm -f tmpunwind.o"
>       WORKING_DIRECTORY ${LUAJIT_SOURCE_DIR}
>       OUTPUT_VARIABLE TESTUNWIND
>       RESULT_VARIABLE TESTUNWIND_RC
> diff --git a/src/Makefile.original b/src/Makefile.original
> index 4d7cda3e..2d014e43 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original
> @@ -344,7 +344,7 @@ ifeq (iOS,$(TARGET_SYS))
> else
>   ifeq (,$(findstring LJ_NO_UNWIND 1,$(TARGET_TESTARCH)))
>     # Find out whether the target toolchain always generates unwind tables.
> -    TARGET_TESTUNWIND=$(shell exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | $(TARGET_CC) -c -x c - -o tmpunwind.o && grep -qU -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o)
> +    TARGET_TESTUNWIND=$(shell exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | $(TARGET_CC) -c -x c - -o tmpunwind.o && { grep -qa -e eh_frame -e __unwind_info tmpunwind.o || grep -qU -e eh_frame -e __unwind_info tmpunwind.o; } && echo E; rm -f tmpunwind.o)
>     ifneq (,$(findstring E,$(TARGET_TESTUNWIND)))
>       TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
>     endif
> -- 
> 2.37.0 (Apple Git-136)
> 

Re: [Tarantool-patches] [PATCH luajit v4 1/8] Cleanup and enable external unwinding for more platforms.

[sergos via Tarantool-patches]

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Hi!

Thanks for the patch, LGTM as part of original [PATCH luajit 1/6] Cleanup and enable external unwinding for more platforms.

Sergos.

> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> (cherry picked from commit e131936133c58de4426c595db2341caf5a1665b5)
> 
> This commit enables external unwinding on all platforms, that
> create unwind tables by default. Corresponding check is added
> to the build routine.
> 
> Also, GC64 mode is now enabled on MacOS by default, as
> non-GC64 mode is forbidden.
> 
> Maxim Kokryashkin:
> * added the description for the patch
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
> .github/workflows/macos-x86_64.yml |  20 +-
> CMakeLists.txt                     |   3 +
> cmake/SetTargetFlags.cmake         |  22 +-
> doc/extensions.html                |  22 +-
> src/Makefile.original              |  11 +-
> src/lj_arch.h                      |  27 ++-
> src/lj_err.c                       | 321 +++++++++++++++--------------
> 7 files changed, 214 insertions(+), 212 deletions(-)
> 
> diff --git a/.github/workflows/macos-x86_64.yml b/.github/workflows/macos-x86_64.yml
> index 840806e3..dafd1796 100644
> --- a/.github/workflows/macos-x86_64.yml
> +++ b/.github/workflows/macos-x86_64.yml
> @@ -35,7 +35,7 @@ jobs:
>       fail-fast: false
>       matrix:
>         BUILDTYPE: [Debug, Release]
> -        GC64: [ON, OFF]
> +        GC64: ON
>         include:
>           - BUILDTYPE: Debug
>             CMAKEFLAGS: -DCMAKE_BUILD_TYPE=Debug -DLUA_USE_ASSERT=ON -DLUA_USE_APICHECK=ON
> @@ -69,15 +69,6 @@ jobs:
>       - name: test
>         run: cmake --build . --parallel --target test
> 
> -  test-tarantool-debug-wo-GC64:
> -    name: Tarantool Debug GC64:OFF
> -    needs: test-luajit
> -    uses: tarantool/tarantool/.github/workflows/luajit-integration.yml@master
> -    with:
> -      GC64: OFF
> -      buildtype: Debug
> -      host: macos-11
> -      revision: ${{ github.sha }}
>   test-tarantool-debug-w-GC64:
>     name: Tarantool Debug GC64:ON
>     needs: test-luajit
> @@ -87,15 +78,6 @@ jobs:
>       buildtype: Debug
>       host: macos-11
>       revision: ${{ github.sha }}
> -  test-tarantool-release-wo-GC64:
> -    name: Tarantool Release GC64:OFF
> -    needs: test-luajit
> -    uses: tarantool/tarantool/.github/workflows/luajit-integration.yml@master
> -    with:
> -      GC64: OFF
> -      buildtype: RelWithDebInfo
> -      host: macos-11
> -      revision: ${{ github.sha }}
>   test-tarantool-release-w-GC64:
>     name: Tarantool Release GC64:ON
>     needs: test-luajit
> diff --git a/CMakeLists.txt b/CMakeLists.txt
> index 8b49f9d7..c4f3ef62 100644
> --- a/CMakeLists.txt
> +++ b/CMakeLists.txt
> @@ -176,6 +176,9 @@ endif()
> 
> # Enable GC64 mode for x64.
> option(LUAJIT_ENABLE_GC64 "GC64 mode for x64" OFF)
> +if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
> +  set(LUAJIT_ENABLE_GC64 ON)
> +endif()
> if(LUAJIT_ENABLE_GC64)
>   AppendFlags(TARGET_C_FLAGS -DLUAJIT_ENABLE_GC64)
> endif()
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index b544d2ac..36896aff 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake
> @@ -15,6 +15,22 @@ endif()
> LuaJITTestArch(TESTARCH "${TARGET_C_FLAGS}")
> LuaJITArch(LUAJIT_ARCH "${TESTARCH}")
> 
> +string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
> +if(UNWIND_POS EQUAL -1)
> +  execute_process(
> +    COMMAND bash -c "exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | ${CMAKE_C_COMPILER} -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o"
> +    WORKING_DIRECTORY ${LUAJIT_SOURCE_DIR}
> +    OUTPUT_VARIABLE TESTUNWIND
> +    RESULT_VARIABLE TESTUNWIND_RC
> +  )
> +  if(TESTUNWIND_RC EQUAL 0)
> +    string(FIND "${TESTUNWIND}" "E" UNW_TEST_POS)
> +    if(NOT UNW_TEST_POS EQUAL -1)
> +      AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> +    endif()
> +  endif()
> +endif()
> +
> # Target-specific compiler options.
> #
> # x86/x64 only: For GCC 4.2 or higher and if you don't intend to
> @@ -25,12 +41,6 @@ if(LUAJIT_ARCH STREQUAL "x86")
> endif()
> 
> if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
> -  if(LUAJIT_ARCH STREQUAL "x64")
> -    # XXX: Set -pagezero_size to hint <mmap> when allocating 32
> -    # bit memory on OSX/x64, otherwise the lower 4GB are blocked.
> -    AppendFlags(TARGET_BIN_FLAGS -pagezero_size 10000 -image_base 100000000)
> -    AppendFlags(TARGET_SHARED_FLAGS -image_base 7fff04c4a000)
> -  endif()
>   AppendFlags(TARGET_SHARED_FLAGS -single_module -undefined dynamic_lookup)
> else() # Linux and FreeBSD.
>   AppendFlags(TARGET_BIN_FLAGS -Wl,-E)
> diff --git a/doc/extensions.html b/doc/extensions.html
> index e0f136e2..777e9928 100644
> --- a/doc/extensions.html
> +++ b/doc/extensions.html
> @@ -395,29 +395,19 @@ the toolchain used to compile LuaJIT:
> <td class="excinterop">Interoperability</td>
> </tr>
> <tr class="odd separate">
> -<td class="excplatform">POSIX/x64, DWARF2 unwinding</td>
> -<td class="exccompiler">GCC 4.3+, Clang</td>
> +<td class="excplatform">External frame unwinding</td>
> +<td class="exccompiler">GCC, Clang, MSVC</td>
> <td class="excinterop"><b style="color: #00a000;">Full</b></td>
> </tr>
> <tr class="even">
> -<td class="excplatform">ARM <tt>-DLUAJIT_UNWIND_EXTERNAL</tt></td>
> -<td class="exccompiler">GCC, Clang</td>
> -<td class="excinterop"><b style="color: #00a000;">Full</b></td>
> -</tr>
> -<tr class="odd">
> -<td class="excplatform">Other platforms, DWARF2 unwinding</td>
> +<td class="excplatform">Internal frame unwinding + DWARF2</td>
> <td class="exccompiler">GCC, Clang</td>
> <td class="excinterop"><b style="color: #c06000;">Limited</b></td>
> </tr>
> -<tr class="even">
> -<td class="excplatform">Windows/x64</td>
> -<td class="exccompiler">MSVC or WinSDK</td>
> -<td class="excinterop"><b style="color: #00a000;">Full</b></td>
> -</tr>
> <tr class="odd">
> -<td class="excplatform">Windows/x86</td>
> -<td class="exccompiler">Any</td>
> -<td class="excinterop"><b style="color: #00a000;">Full</b></td>
> +<td class="excplatform">Windows 64 bit</td>
> +<td class="exccompiler">non-MSVC</td>
> +<td class="excinterop"><b style="color: #c06000;">Limited</b></td>
> </tr>
> <tr class="even">
> <td class="excplatform">Other platforms</td>
> diff --git a/src/Makefile.original b/src/Makefile.original
> index dd1c6a76..c9609700 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original
> @@ -320,6 +320,13 @@ else
> ifeq (,$(shell $(TARGET_CC) -o /dev/null -c -x c /dev/null -fno-stack-protector 2>/dev/null || echo 1))
>   TARGET_XCFLAGS+= -fno-stack-protector
> endif
> +ifeq (,$(findstring LJ_NO_UNWIND 1,$(TARGET_TESTARCH)))
> +  # Find out whether the target toolchain always generates unwind tables.
> +  TARGET_TESTUNWIND=$(shell exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | $(TARGET_CC) -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o)
> +  ifneq (,$(findstring E,$(TARGET_TESTUNWIND)))
> +    TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
> +  endif
> +endif
> ifeq (Darwin,$(TARGET_SYS))
>   ifeq (,$(MACOSX_DEPLOYMENT_TARGET))
>     export MACOSX_DEPLOYMENT_TARGET=10.4
> @@ -328,10 +335,6 @@ ifeq (Darwin,$(TARGET_SYS))
>   TARGET_XSHLDFLAGS= -dynamiclib -single_module -undefined dynamic_lookup -fPIC
>   TARGET_DYNXLDOPTS=
>   TARGET_XSHLDFLAGS+= -install_name $(TARGET_DYLIBPATH) -compatibility_version $(MAJVER).$(MINVER) -current_version $(MAJVER).$(MINVER).$(RELVER)
> -  ifeq (x64,$(TARGET_LJARCH))
> -    TARGET_XLDFLAGS+= -pagezero_size 10000 -image_base 100000000
> -    TARGET_XSHLDFLAGS+= -image_base 7fff04c4a000
> -  endif
> else
> ifeq (iOS,$(TARGET_SYS))
>   TARGET_STRIP+= -x
> diff --git a/src/lj_arch.h b/src/lj_arch.h
> index 40129d9e..730be5bf 100644
> --- a/src/lj_arch.h
> +++ b/src/lj_arch.h
> @@ -152,11 +152,6 @@
> #define LJ_ARCH_NAME		"x86"
> #define LJ_ARCH_BITS		32
> #define LJ_ARCH_ENDIAN		LUAJIT_LE
> -#if LJ_TARGET_WINDOWS || LJ_TARGET_CYGWIN
> -#define LJ_ABI_WIN		1
> -#else
> -#define LJ_ABI_WIN		0
> -#endif
> #define LJ_TARGET_X86		1
> #define LJ_TARGET_X86ORX64	1
> #define LJ_TARGET_EHRETREG	0
> @@ -170,11 +165,6 @@
> #define LJ_ARCH_NAME		"x64"
> #define LJ_ARCH_BITS		64
> #define LJ_ARCH_ENDIAN		LUAJIT_LE
> -#if LJ_TARGET_WINDOWS || LJ_TARGET_CYGWIN
> -#define LJ_ABI_WIN		1
> -#else
> -#define LJ_ABI_WIN		0
> -#endif
> #define LJ_TARGET_X64		1
> #define LJ_TARGET_X86ORX64	1
> #define LJ_TARGET_EHRETREG	0
> @@ -185,6 +175,8 @@
> #define LJ_ARCH_NUMMODE		LJ_NUMMODE_SINGLE_DUAL
> #ifdef LUAJIT_ENABLE_GC64
> #define LJ_TARGET_GC64		1
> +#elif LJ_TARGET_OSX
> +#error "macOS requires GC64 -- don't disable it"
> #endif
> 
> #elif LUAJIT_TARGET == LUAJIT_ARCH_ARM
> @@ -566,15 +558,22 @@
> #define LJ_NO_SYSTEM		1
> #endif
> 
> -#if !defined(LUAJIT_NO_UNWIND) && __GNU_COMPACT_EH__
> -/* NYI: no support for compact unwind specification, yet. */
> -#define LUAJIT_NO_UNWIND	1
> +#if LJ_TARGET_WINDOWS || LJ_TARGET_CYGWIN
> +#define LJ_ABI_WIN		1
> +#else
> +#define LJ_ABI_WIN		0
> #endif
> 
> -#if defined(LUAJIT_NO_UNWIND) || defined(__symbian__) || LJ_TARGET_IOS || LJ_TARGET_PS3 || LJ_TARGET_PS4
> +#if defined(LUAJIT_NO_UNWIND) || __GNU_COMPACT_EH__ || defined(__symbian__) || LJ_TARGET_IOS || LJ_TARGET_PS3 || LJ_TARGET_PS4
> #define LJ_NO_UNWIND		1
> #endif
> 
> +#if !LJ_NO_UNWIND && !defined(LUAJIT_UNWIND_INTERNAL) && (LJ_ABI_WIN || (defined(LUAJIT_UNWIND_EXTERNAL) && (defined(__GNUC__) || defined(__clang__))))
> +#define LJ_UNWIND_EXT		1
> +#else
> +#define LJ_UNWIND_EXT		0
> +#endif
> +
> /* Compatibility with Lua 5.1 vs. 5.2. */
> #ifdef LUAJIT_ENABLE_LUA52COMPAT
> #define LJ_52			1
> diff --git a/src/lj_err.c b/src/lj_err.c
> index c310daf6..298e5434 100644
> --- a/src/lj_err.c
> +++ b/src/lj_err.c
> @@ -29,12 +29,18 @@
> ** Pros and Cons:
> **
> ** - EXT requires unwind tables for *all* functions on the C stack between
> -**   the pcall/catch and the error/throw. This is the default on x64,
> -**   but needs to be manually enabled on x86/PPC for non-C++ code.
> +**   the pcall/catch and the error/throw. C modules used by Lua code can
> +**   throw errors, so these need to have unwind tables, too. Transitively
> +**   this applies to all system libraries used by C modules -- at least
> +**   when they have callbacks which may throw an error.
> **
> -** - INT is faster when actually throwing errors (but this happens rarely).
> +** - INT is faster when actually throwing errors, but this happens rarely.
> **   Setting up error handlers is zero-cost in any case.
> **
> +** - INT needs to save *all* callee-saved registers when entering the
> +**   interpreter. EXT only needs to save those actually used inside the
> +**   interpreter. JIT-compiled code may need to save some more.
> +**
> ** - EXT provides full interoperability with C++ exceptions. You can throw
> **   Lua errors or C++ exceptions through a mix of Lua frames and C++ frames.
> **   C++ destructors are called as needed. C++ exceptions caught by pcall
> @@ -46,27 +52,33 @@
> **   the wrapper function feature. Lua errors thrown through C++ frames
> **   cannot be caught by C++ code and C++ destructors are not run.
> **
> -** EXT is the default on x64 systems and on Windows, INT is the default on all
> -** other systems.
> +** EXT is the default on all systems where the toolchain produces unwind
> +** tables by default (*). This is hard-coded and/or detected in src/Makefile.
> +** You can thwart the detection with: TARGET_XCFLAGS=-DLUAJIT_UNWIND_INTERNAL
> +**
> +** INT is the default on all other systems.
> +**
> +** EXT can be manually enabled for toolchains that are able to produce
> +** conforming unwind tables:
> +**   "TARGET_XCFLAGS=-funwind-tables -DLUAJIT_UNWIND_EXTERNAL"
> +** As explained above, *all* C code used directly or indirectly by LuaJIT
> +** must be compiled with -funwind-tables (or -fexceptions). C++ code must
> +** *not* be compiled with -fno-exceptions.
> +**
> +** If you're unsure whether error handling inside the VM works correctly,
> +** try running this and check whether it prints "OK":
> **
> -** EXT can be manually enabled on POSIX systems using GCC and DWARF2 stack
> -** unwinding with -DLUAJIT_UNWIND_EXTERNAL. *All* C code must be compiled
> -** with -funwind-tables (or -fexceptions). This includes LuaJIT itself (set
> -** TARGET_CFLAGS), all of your C/Lua binding code, all loadable C modules
> -** and all C libraries that have callbacks which may be used to call back
> -** into Lua. C++ code must *not* be compiled with -fno-exceptions.
> +**   luajit -e "print(select(2, load('OK')):match('OK'))"
> **
> -** EXT is mandatory on WIN64 since the calling convention has an abundance
> -** of callee-saved registers (rbx, rbp, rsi, rdi, r12-r15, xmm6-xmm15).
> -** The POSIX/x64 interpreter only saves r12/r13 for INT (e.g. PS4).
> +** (*) Originally, toolchains only generated unwind tables for C++ code. For
> +** interoperability reasons, this can be manually enabled for plain C code,
> +** too (with -funwind-tables). With the introduction of the x64 architecture,
> +** the corresponding POSIX and Windows ABIs mandated unwind tables for all
> +** code. Over the following years most desktop and server platforms have
> +** enabled unwind tables by default on all architectures. OTOH mobile and
> +** embedded platforms do not consistently mandate unwind tables.
> */
> 
> -#if defined(__GNUC__) && (LJ_TARGET_X64 || defined(LUAJIT_UNWIND_EXTERNAL)) && !LJ_NO_UNWIND
> -#define LJ_UNWIND_EXT	1
> -#elif LJ_TARGET_WINDOWS
> -#define LJ_UNWIND_EXT	1
> -#endif
> -
> /* -- Error messages ------------------------------------------------------ */
> 
> /* Error message strings. */
> @@ -183,7 +195,125 @@ static void *err_unwind(lua_State *L, void *stopcf, int errcode)
> 
> /* -- External frame unwinding -------------------------------------------- */
> 
> -#if defined(__GNUC__) && !LJ_NO_UNWIND && !LJ_ABI_WIN
> +#if LJ_ABI_WIN
> +
> +/*
> +** Someone in Redmond owes me several days of my life. A lot of this is
> +** undocumented or just plain wrong on MSDN. Some of it can be gathered
> +** from 3rd party docs or must be found by trial-and-error. They really
> +** don't want you to write your own language-specific exception handler
> +** or to interact gracefully with MSVC. :-(
> +**
> +** Apparently MSVC doesn't call C++ destructors for foreign exceptions
> +** unless you compile your C++ code with /EHa. Unfortunately this means
> +** catch (...) also catches things like access violations. The use of
> +** _set_se_translator doesn't really help, because it requires /EHa, too.
> +*/
> +
> +#define WIN32_LEAN_AND_MEAN
> +#include <windows.h>
> +
> +#if LJ_TARGET_X86
> +typedef void *UndocumentedDispatcherContext;  /* Unused on x86. */
> +#else
> +/* Taken from: http://www.nynaeve.net/?p=99 */
> +typedef struct UndocumentedDispatcherContext {
> +  ULONG64 ControlPc;
> +  ULONG64 ImageBase;
> +  PRUNTIME_FUNCTION FunctionEntry;
> +  ULONG64 EstablisherFrame;
> +  ULONG64 TargetIp;
> +  PCONTEXT ContextRecord;
> +  void (*LanguageHandler)(void);
> +  PVOID HandlerData;
> +  PUNWIND_HISTORY_TABLE HistoryTable;
> +  ULONG ScopeIndex;
> +  ULONG Fill0;
> +} UndocumentedDispatcherContext;
> +#endif
> +
> +/* Another wild guess. */
> +extern void __DestructExceptionObject(EXCEPTION_RECORD *rec, int nothrow);
> +
> +#if LJ_TARGET_X64 && defined(MINGW_SDK_INIT)
> +/* Workaround for broken MinGW64 declaration. */
> +VOID RtlUnwindEx_FIXED(PVOID,PVOID,PVOID,PVOID,PVOID,PVOID) asm("RtlUnwindEx");
> +#define RtlUnwindEx RtlUnwindEx_FIXED
> +#endif
> +
> +#define LJ_MSVC_EXCODE		((DWORD)0xe06d7363)
> +#define LJ_GCC_EXCODE		((DWORD)0x20474343)
> +
> +#define LJ_EXCODE		((DWORD)0xe24c4a00)
> +#define LJ_EXCODE_MAKE(c)	(LJ_EXCODE | (DWORD)(c))
> +#define LJ_EXCODE_CHECK(cl)	(((cl) ^ LJ_EXCODE) <= 0xff)
> +#define LJ_EXCODE_ERRCODE(cl)	((int)((cl) & 0xff))
> +
> +/* Windows exception handler for interpreter frame. */
> +LJ_FUNCA int lj_err_unwind_win(EXCEPTION_RECORD *rec,
> +  void *f, CONTEXT *ctx, UndocumentedDispatcherContext *dispatch)
> +{
> +#if LJ_TARGET_X86
> +  void *cf = (char *)f - CFRAME_OFS_SEH;
> +#else
> +  void *cf = f;
> +#endif
> +  lua_State *L = cframe_L(cf);
> +  int errcode = LJ_EXCODE_CHECK(rec->ExceptionCode) ?
> +		LJ_EXCODE_ERRCODE(rec->ExceptionCode) : LUA_ERRRUN;
> +  if ((rec->ExceptionFlags & 6)) {  /* EH_UNWINDING|EH_EXIT_UNWIND */
> +    /* Unwind internal frames. */
> +    err_unwind(L, cf, errcode);
> +  } else {
> +    void *cf2 = err_unwind(L, cf, 0);
> +    if (cf2) {  /* We catch it, so start unwinding the upper frames. */
> +      if (rec->ExceptionCode == LJ_MSVC_EXCODE ||
> +	  rec->ExceptionCode == LJ_GCC_EXCODE) {
> +#if !LJ_TARGET_CYGWIN
> +	__DestructExceptionObject(rec, 1);
> +#endif
> +	setstrV(L, L->top++, lj_err_str(L, LJ_ERR_ERRCPP));
> +      } else if (!LJ_EXCODE_CHECK(rec->ExceptionCode)) {
> +	/* Don't catch access violations etc. */
> +	return 1;  /* ExceptionContinueSearch */
> +      }
> +#if LJ_TARGET_X86
> +      UNUSED(ctx);
> +      UNUSED(dispatch);
> +      /* Call all handlers for all lower C frames (including ourselves) again
> +      ** with EH_UNWINDING set. Then call the specified function, passing cf
> +      ** and errcode.
> +      */
> +      lj_vm_rtlunwind(cf, (void *)rec,
> +	(cframe_unwind_ff(cf2) && errcode != LUA_YIELD) ?
> +	(void *)lj_vm_unwind_ff : (void *)lj_vm_unwind_c, errcode);
> +      /* lj_vm_rtlunwind does not return. */
> +#else
> +      /* Unwind the stack and call all handlers for all lower C frames
> +      ** (including ourselves) again with EH_UNWINDING set. Then set
> +      ** stack pointer = cf, result = errcode and jump to the specified target.
> +      */
> +      RtlUnwindEx(cf, (void *)((cframe_unwind_ff(cf2) && errcode != LUA_YIELD) ?
> +			       lj_vm_unwind_ff_eh :
> +			       lj_vm_unwind_c_eh),
> +		  rec, (void *)(uintptr_t)errcode, ctx, dispatch->HistoryTable);
> +      /* RtlUnwindEx should never return. */
> +#endif
> +    }
> +  }
> +  return 1;  /* ExceptionContinueSearch */
> +}
> +
> +/* Raise Windows exception. */
> +static void err_raise_ext(global_State *g, int errcode)
> +{
> +#if LJ_HASJIT
> +  setmref(g->jit_base, NULL);
> +#endif
> +  RaiseException(LJ_EXCODE_MAKE(errcode), 1 /* EH_NONCONTINUABLE */, 0, NULL);
> +}
> +
> +#elif !LJ_NO_UNWIND && (defined(__GNUC__) || defined(__clang__))
> 
> /*
> ** We have to use our own definitions instead of the mandatory (!) unwind.h,
> @@ -232,7 +362,6 @@ LJ_FUNCA int lj_err_unwind_dwarf(int version, int actions,
>   lua_State *L;
>   if (version != 1)
>     return _URC_FATAL_PHASE1_ERROR;
> -  UNUSED(uexclass);
>   cf = (void *)_Unwind_GetCFA(ctx);
>   L = cframe_L(cf);
>   if ((actions & _UA_SEARCH_PHASE)) {
> @@ -280,6 +409,9 @@ LJ_FUNCA int lj_err_unwind_dwarf(int version, int actions,
>     ** it on non-x64 because the interpreter restores all callee-saved regs.
>     */
>     lj_err_throw(L, errcode);
> +#if LJ_TARGET_X64
> +#error "Broken build system -- only use the provided Makefiles!"
> +#endif
> #endif
>   }
>   return _URC_CONTINUE_UNWIND;
> @@ -292,14 +424,6 @@ static _Unwind_Exception static_uex;
> #else
> static __thread _Unwind_Exception static_uex;
> #endif
> -
> -/* Raise DWARF2 exception. */
> -static void err_raise_ext(int errcode)
> -{
> -  static_uex.exclass = LJ_UEXCLASS_MAKE(errcode);
> -  static_uex.excleanup = NULL;
> -  _Unwind_RaiseException(&static_uex);
> -}
> #endif
> 
> #else /* LJ_TARGET_ARM */
> @@ -373,132 +497,22 @@ LJ_FUNCA int lj_err_unwind_arm(int state, _Unwind_Control_Block *ucb,
> 
> #if LJ_UNWIND_EXT
> static __thread _Unwind_Control_Block static_uex;
> +#endif
> +#endif /* LJ_TARGET_ARM */
> 
> -static void err_raise_ext(int errcode)
> +#if LJ_UNWIND_EXT
> +/* Raise external exception. */
> +static void err_raise_ext(global_State *g, int errcode)
> {
> +#if LJ_HASJIT
> +  setmref(g->jit_base, NULL);
> +#endif
>   memset(&static_uex, 0, sizeof(static_uex));
>   static_uex.exclass = LJ_UEXCLASS_MAKE(errcode);
>   _Unwind_RaiseException(&static_uex);
> }
> #endif
> 
> -#endif /* LJ_TARGET_ARM */
> -
> -#elif LJ_ABI_WIN
> -
> -/*
> -** Someone in Redmond owes me several days of my life. A lot of this is
> -** undocumented or just plain wrong on MSDN. Some of it can be gathered
> -** from 3rd party docs or must be found by trial-and-error. They really
> -** don't want you to write your own language-specific exception handler
> -** or to interact gracefully with MSVC. :-(
> -**
> -** Apparently MSVC doesn't call C++ destructors for foreign exceptions
> -** unless you compile your C++ code with /EHa. Unfortunately this means
> -** catch (...) also catches things like access violations. The use of
> -** _set_se_translator doesn't really help, because it requires /EHa, too.
> -*/
> -
> -#define WIN32_LEAN_AND_MEAN
> -#include <windows.h>
> -
> -#if LJ_TARGET_X64
> -/* Taken from: http://www.nynaeve.net/?p=99 */
> -typedef struct UndocumentedDispatcherContext {
> -  ULONG64 ControlPc;
> -  ULONG64 ImageBase;
> -  PRUNTIME_FUNCTION FunctionEntry;
> -  ULONG64 EstablisherFrame;
> -  ULONG64 TargetIp;
> -  PCONTEXT ContextRecord;
> -  void (*LanguageHandler)(void);
> -  PVOID HandlerData;
> -  PUNWIND_HISTORY_TABLE HistoryTable;
> -  ULONG ScopeIndex;
> -  ULONG Fill0;
> -} UndocumentedDispatcherContext;
> -#else
> -typedef void *UndocumentedDispatcherContext;
> -#endif
> -
> -/* Another wild guess. */
> -extern void __DestructExceptionObject(EXCEPTION_RECORD *rec, int nothrow);
> -
> -#if LJ_TARGET_X64 && defined(MINGW_SDK_INIT)
> -/* Workaround for broken MinGW64 declaration. */
> -VOID RtlUnwindEx_FIXED(PVOID,PVOID,PVOID,PVOID,PVOID,PVOID) asm("RtlUnwindEx");
> -#define RtlUnwindEx RtlUnwindEx_FIXED
> -#endif
> -
> -#define LJ_MSVC_EXCODE		((DWORD)0xe06d7363)
> -#define LJ_GCC_EXCODE		((DWORD)0x20474343)
> -
> -#define LJ_EXCODE		((DWORD)0xe24c4a00)
> -#define LJ_EXCODE_MAKE(c)	(LJ_EXCODE | (DWORD)(c))
> -#define LJ_EXCODE_CHECK(cl)	(((cl) ^ LJ_EXCODE) <= 0xff)
> -#define LJ_EXCODE_ERRCODE(cl)	((int)((cl) & 0xff))
> -
> -/* Windows exception handler for interpreter frame. */
> -LJ_FUNCA int lj_err_unwind_win(EXCEPTION_RECORD *rec,
> -  void *f, CONTEXT *ctx, UndocumentedDispatcherContext *dispatch)
> -{
> -#if LJ_TARGET_X64
> -  void *cf = f;
> -#else
> -  void *cf = (char *)f - CFRAME_OFS_SEH;
> -#endif
> -  lua_State *L = cframe_L(cf);
> -  int errcode = LJ_EXCODE_CHECK(rec->ExceptionCode) ?
> -		LJ_EXCODE_ERRCODE(rec->ExceptionCode) : LUA_ERRRUN;
> -  if ((rec->ExceptionFlags & 6)) {  /* EH_UNWINDING|EH_EXIT_UNWIND */
> -    /* Unwind internal frames. */
> -    err_unwind(L, cf, errcode);
> -  } else {
> -    void *cf2 = err_unwind(L, cf, 0);
> -    if (cf2) {  /* We catch it, so start unwinding the upper frames. */
> -      if (rec->ExceptionCode == LJ_MSVC_EXCODE ||
> -	  rec->ExceptionCode == LJ_GCC_EXCODE) {
> -#if LJ_TARGET_WINDOWS
> -	__DestructExceptionObject(rec, 1);
> -#endif
> -	setstrV(L, L->top++, lj_err_str(L, LJ_ERR_ERRCPP));
> -      } else if (!LJ_EXCODE_CHECK(rec->ExceptionCode)) {
> -	/* Don't catch access violations etc. */
> -	return 1;  /* ExceptionContinueSearch */
> -      }
> -#if LJ_TARGET_X64
> -      /* Unwind the stack and call all handlers for all lower C frames
> -      ** (including ourselves) again with EH_UNWINDING set. Then set
> -      ** rsp = cf, rax = errcode and jump to the specified target.
> -      */
> -      RtlUnwindEx(cf, (void *)((cframe_unwind_ff(cf2) && errcode != LUA_YIELD) ?
> -			       lj_vm_unwind_ff_eh :
> -			       lj_vm_unwind_c_eh),
> -		  rec, (void *)(uintptr_t)errcode, ctx, dispatch->HistoryTable);
> -      /* RtlUnwindEx should never return. */
> -#else
> -      UNUSED(ctx);
> -      UNUSED(dispatch);
> -      /* Call all handlers for all lower C frames (including ourselves) again
> -      ** with EH_UNWINDING set. Then call the specified function, passing cf
> -      ** and errcode.
> -      */
> -      lj_vm_rtlunwind(cf, (void *)rec,
> -	(cframe_unwind_ff(cf2) && errcode != LUA_YIELD) ?
> -	(void *)lj_vm_unwind_ff : (void *)lj_vm_unwind_c, errcode);
> -      /* lj_vm_rtlunwind does not return. */
> -#endif
> -    }
> -  }
> -  return 1;  /* ExceptionContinueSearch */
> -}
> -
> -/* Raise Windows exception. */
> -static void err_raise_ext(int errcode)
> -{
> -  RaiseException(LJ_EXCODE_MAKE(errcode), 1 /* EH_NONCONTINUABLE */, 0, NULL);
> -}
> -
> #endif
> 
> /* -- Error handling ------------------------------------------------------ */
> @@ -508,22 +522,23 @@ LJ_NOINLINE void LJ_FASTCALL lj_err_throw(lua_State *L, int errcode)
> {
>   global_State *g = G(L);
>   lj_trace_abort(g);
> -  setmref(g->jit_base, NULL);
>   L->status = LUA_OK;
> #if LJ_UNWIND_EXT
> -  err_raise_ext(errcode);
> +  err_raise_ext(g, errcode);
>   /*
>   ** A return from this function signals a corrupt C stack that cannot be
>   ** unwound. We have no choice but to call the panic function and exit.
>   **
>   ** Usually this is caused by a C function without unwind information.
> -  ** This should never happen on x64, but may happen if you've manually
> -  ** enabled LUAJIT_UNWIND_EXTERNAL and forgot to recompile *every*
> -  ** non-C++ file with -funwind-tables.
> +  ** This may happen if you've manually enabled LUAJIT_UNWIND_EXTERNAL
> +  ** and forgot to recompile *every* non-C++ file with -funwind-tables.
>   */
>   if (G(L)->panic)
>     G(L)->panic(L);
> #else
> +#if LJ_HASJIT
> +  setmref(g->jit_base, NULL);
> +#endif
>   {
>     void *cf = err_unwind(L, NULL, errcode);
>     if (cframe_unwind_ff(cf))
> -- 
> 2.37.0 (Apple Git-136)
> 


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Re: [Tarantool-patches] [PATCH luajit v4 2/8] OSX: Fix build by hardcoding external frame unwinding.

[sergos via Tarantool-patches]

Hi!

Thanks for the patch!
LGTM.

Sergos


> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> Apparently they can't even get 'grep' right, let alone a keyboard.
> 
> (cherry picked from commit d4a554d6ee1507f7313641b26ed09bf1b518fa1f)
> 
> MacOS uses BSD grep, which is slightly different from GNU grep.
> Because of that, the shell script determining whether external
> unwinding is possible doesn't work right.
> 
> External unwinding is possible on MacOS, so this patch enables
> it by default.
> 
> Maxim Kokryashkin:
> * added the description for the problem
> 
> Needed for tarantool/tarantool#6096
> Needed for tarantool/tarantool#7230
> ---
> cmake/SetTargetFlags.cmake | 28 ++++++++++++++++------------
> src/Makefile.original      | 15 ++++++++-------
> 2 files changed, 24 insertions(+), 19 deletions(-)
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index 36896aff..a5a3407f 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake
> @@ -15,18 +15,22 @@ endif()
> LuaJITTestArch(TESTARCH "${TARGET_C_FLAGS}")
> LuaJITArch(LUAJIT_ARCH "${TESTARCH}")
> 
> -string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
> -if(UNWIND_POS EQUAL -1)
> -  execute_process(
> -    COMMAND bash -c "exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | ${CMAKE_C_COMPILER} -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o"
> -    WORKING_DIRECTORY ${LUAJIT_SOURCE_DIR}
> -    OUTPUT_VARIABLE TESTUNWIND
> -    RESULT_VARIABLE TESTUNWIND_RC
> -  )
> -  if(TESTUNWIND_RC EQUAL 0)
> -    string(FIND "${TESTUNWIND}" "E" UNW_TEST_POS)
> -    if(NOT UNW_TEST_POS EQUAL -1)
> -      AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> +if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
> +  AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> +else()
> +  string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
> +  if(UNWIND_POS EQUAL -1)
> +    execute_process(
> +      COMMAND bash -c "exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | ${CMAKE_C_COMPILER} -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o"
> +      WORKING_DIRECTORY ${LUAJIT_SOURCE_DIR}
> +      OUTPUT_VARIABLE TESTUNWIND
> +      RESULT_VARIABLE TESTUNWIND_RC
> +    )
> +    if(TESTUNWIND_RC EQUAL 0)
> +      string(FIND "${TESTUNWIND}" "E" UNW_TEST_POS)
> +      if(NOT UNW_TEST_POS EQUAL -1)
> +        AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> +      endif()
>     endif()
>   endif()
> endif()
> diff --git a/src/Makefile.original b/src/Makefile.original
> index c9609700..d1373b40 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original
> @@ -320,18 +320,12 @@ else
> ifeq (,$(shell $(TARGET_CC) -o /dev/null -c -x c /dev/null -fno-stack-protector 2>/dev/null || echo 1))
>   TARGET_XCFLAGS+= -fno-stack-protector
> endif
> -ifeq (,$(findstring LJ_NO_UNWIND 1,$(TARGET_TESTARCH)))
> -  # Find out whether the target toolchain always generates unwind tables.
> -  TARGET_TESTUNWIND=$(shell exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | $(TARGET_CC) -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o)
> -  ifneq (,$(findstring E,$(TARGET_TESTUNWIND)))
> -    TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
> -  endif
> -endif
> ifeq (Darwin,$(TARGET_SYS))
>   ifeq (,$(MACOSX_DEPLOYMENT_TARGET))
>     export MACOSX_DEPLOYMENT_TARGET=10.4
>   endif
>   TARGET_STRIP+= -x
> +  TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
>   TARGET_XSHLDFLAGS= -dynamiclib -single_module -undefined dynamic_lookup -fPIC
>   TARGET_DYNXLDOPTS=
>   TARGET_XSHLDFLAGS+= -install_name $(TARGET_DYLIBPATH) -compatibility_version $(MAJVER).$(MINVER) -current_version $(MAJVER).$(MINVER).$(RELVER)
> @@ -345,6 +339,13 @@ ifeq (iOS,$(TARGET_SYS))
>     TARGET_XCFLAGS+= -fno-omit-frame-pointer
>   endif
> else
> +  ifeq (,$(findstring LJ_NO_UNWIND 1,$(TARGET_TESTARCH)))
> +    # Find out whether the target toolchain always generates unwind tables.
> +    TARGET_TESTUNWIND=$(shell exec 2>/dev/null; echo 'extern void b(void);int a(void){b();return 0;}' | $(TARGET_CC) -c -x c - -o tmpunwind.o && grep -qa -e eh_frame -e __unwind_info tmpunwind.o && echo E; rm -f tmpunwind.o)
> +    ifneq (,$(findstring E,$(TARGET_TESTUNWIND)))
> +      TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
> +    endif
> +  endif
>   ifneq (SunOS,$(TARGET_SYS))
>     ifneq (PS3,$(TARGET_SYS))
>       TARGET_XLDFLAGS+= -Wl,-E
> -- 
> 2.37.0 (Apple Git-136)
> 

Re: [Tarantool-patches] [PATCH luajit v4 3/8] OSX/ARM64: Disable external unwinding for now.

[sergos via Tarantool-patches]

Hi!

Thanks for the patch!

LGTM

Sergos


> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> From: Mike Pall <mike>
> 
> This reduces functionality, e.g. no handling of on-trace errors.
> Someone with very deep knowledge about macOS and MACH-O/DWARF stack
> unwinding internals is needed to fix this. See issue #698.
> 
> (cherry picked from commit 27ee3bcd79b12a0c71f00427ee1a2e486c684486)
> 
> ARM64 interpreter doesn't have unwind info for Mach-O assembler
> format, which makes unwinding impossible. Because of that
> external unwinding on ARM64 MacOS is temporarily disabled.
> 
> Maxim Kokryashkin:
> * added the description for the problem
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
> cmake/SetTargetFlags.cmake | 4 +++-
> src/Makefile.original      | 5 ++++-
> 2 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index a5a3407f..d99e1f9a 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake
> @@ -16,7 +16,9 @@ LuaJITTestArch(TESTARCH "${TARGET_C_FLAGS}")
> LuaJITArch(LUAJIT_ARCH "${TESTARCH}")
> 
> if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
> -  AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> +  if(NOT LUAJIT_ARCH STREQUAL "arm64")
> +    AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> +  endif()
> else()
>   string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
>   if(UNWIND_POS EQUAL -1)
> diff --git a/src/Makefile.original b/src/Makefile.original
> index d1373b40..5826a56a 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original
> @@ -325,7 +325,10 @@ ifeq (Darwin,$(TARGET_SYS))
>     export MACOSX_DEPLOYMENT_TARGET=10.4
>   endif
>   TARGET_STRIP+= -x
> -  TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
> +  # Ext. unwinding is broken on OSX/ARM64 until someone finds a fix. See #698.
> +  ifneq (arm64,$(TARGET_LJARCH))
> +    TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
> +  endif
>   TARGET_XSHLDFLAGS= -dynamiclib -single_module -undefined dynamic_lookup -fPIC
>   TARGET_DYNXLDOPTS=
>   TARGET_XSHLDFLAGS+= -install_name $(TARGET_DYLIBPATH) -compatibility_version $(MAJVER).$(MINVER) -current_version $(MAJVER).$(MINVER).$(RELVER)
> -- 
> 2.37.0 (Apple Git-136)
> 

Re: [Tarantool-patches] [PATCH luajit v4 4/8] ARM64: Reorder interpreter stack frame and fix unwinding.

[Sergey Kaplun via Tarantool-patches]

Hi, Maksim!
Thanks for the fixes!

LGTM, with minor nits below.

On 28.10.22, Maksim Kokryashkin wrote:
> From: Mike Pall <mike>
> 
> Reported by Yichun Zhang. Fixes #722.
> May help towards fixing #698, too.
> 
> (cherry picked from commit 421c4c798791d27b7f967df39891c4e4fa1d107c)
> 
> The `_Unwind_Find_FDE` fails to find the FDE (frame descriptor
> element) for `lj_vm_ffi_call` in DWARF unwind info, despite
> the presence of its data in the `.debug_frame` section.

Strictly saying, for these purposes the `.eh_frame` section is used, as
far as unwinder looks for its entries during unwinding. But, yes,
`.debug_frame` had incorrect entries, too.

> 
> LuaJIT emits its own DWARF entries for the CFI (call frame
> information, section 6.4.1 in DWARF standard)[1].The FP

Typo: s<].T><]. T>

> register value is vital to perform unwinding, and it is
> possible to restore that register using the Canonical
> Frame Address, or CFA. It can be obtained as `CFA - offset`.
> By default, the CFA register is SP, however, it can be
> changed to any other.
> 
> According to ARM's calling convention, the first eight

Minor: s/ARM's/ARM (A64)'s/

> arguments of a function must be passed in x0-x7 registers,
> and all the remaining must be passed on the stack. The
> latter fact is important because it affects the SP and,
> because of that, the CFA invalidates. This patch changes
> the CFA register to the FP for the lj_vm_ffi_call, which

Minor: should it be `lj_vm_ffi_call`?

> fixes the issue.
> 
> All the other changes are made just for refactoring purposes.
> 
> [1]: https://dwarfstd.org/doc/DWARF5.pdf
> 
> Maxim Kokryashkin:
> * added the description and the test case for the problem
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
>  src/lj_frame.h                                |  12 +-
>  src/vm_arm64.dasc                             | 189 ++++++++++++++----
>  .../lj-698-arm-pcall-panic.test.lua           |  18 ++
>  3 files changed, 170 insertions(+), 49 deletions(-)
>  create mode 100644 test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
> 
> diff --git a/src/lj_frame.h b/src/lj_frame.h
> index 9fd63fa2..1e4adaa3 100644
> --- a/src/lj_frame.h
> +++ b/src/lj_frame.h

<snipped>

> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
> index 313cc94f..ad57bca3 100644
> --- a/src/vm_arm64.dasc
> +++ b/src/vm_arm64.dasc

<snipped>

> diff --git a/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua b/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
> new file mode 100644
> index 00000000..88476d3e
> --- /dev/null
> +++ b/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
> @@ -0,0 +1,18 @@
> +local tap = require('tap')
> +
> +-- See also https://github.com/LuaJIT/LuaJIT/issues/698.
> +local test = tap.test('lj-418-arm-pcall-panic')

Typo: s/418/698/
Also, it is better to mention (in the test name too) LuaJIT/LuaJIT#722
issue (it's already mentioned in the commit message), at least it's
given an idea about reproducing:
https://github.com/LuaJIT/LuaJIT/issues/722

> +test:plan(1)
> +
> +local ffi = require('ffi')
> +-- The test case below was taken from the LuaJIT-tests
> +-- suite (lib/ffi/ffi_callback.lua), and should be removed
> +-- after the integration of the mentioned suite.

Minor: I suppose that you mean "part of the suite".

> +local runner = ffi.cast("int (*)(int, int, int, int, int, int, int, int, int)",

Minor: please use single quotes if it's possible.

> +                        function() error("test") end
> +                      )

Nit: something strange with alignment. Can we just join these lines like
the follwing:
| local runner = ffi.cast('int (*)(int, int, int, int, int, int, int, int, int)',
|                         function() error('test') end)

It's good to mention the rationale of the choice this amount of
arguments (just copying description from the commit message is enough).

> +local st = pcall(runner, 1, 1, 1, 1, 1, 1, 1, 1, 1)

Minor: should we check the error message too?
Feel free to ignore.

> +test:ok(not st, 'error handling completed correctly')
> +
> +os.exit(test:check() and 0 or 1)
> -- 
> 2.37.0 (Apple Git-136)
> 

-- 
Best regards,
Sergey Kaplun

Re: [Tarantool-patches] [PATCH luajit v4 4/8] ARM64: Reorder interpreter stack frame and fix unwinding.

[Maxim Kokryashkin via Tarantool-patches]

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Hi!
Thanks for the review!
> 
>>Hi, Maksim!
>>Thanks for the fixes!
>>
>>LGTM, with minor nits below.
>>
>>On 28.10.22, Maksim Kokryashkin wrote:
>>> From: Mike Pall <mike>
>>>
>>> Reported by Yichun Zhang. Fixes #722.
>>> May help towards fixing #698, too.
>>>
>>> (cherry picked from commit 421c4c798791d27b7f967df39891c4e4fa1d107c)
>>>
>>> The `_Unwind_Find_FDE` fails to find the FDE (frame descriptor
>>> element) for `lj_vm_ffi_call` in DWARF unwind info, despite
>>> the presence of its data in the `.debug_frame` section.
>>
>>Strictly saying, for these purposes the `.eh_frame` section is used, as
>>far as unwinder looks for its entries during unwinding. But, yes,
>>`.debug_frame` had incorrect entries, too.
>Fixed.
>>
>>>
>>> LuaJIT emits its own DWARF entries for the CFI (call frame
>>> information, section 6.4.1 in DWARF standard)[1].The FP
>>
>>Typo: s<].T><]. T>
>Fixed.
>>
>>> register value is vital to perform unwinding, and it is
>>> possible to restore that register using the Canonical
>>> Frame Address, or CFA. It can be obtained as `CFA - offset`.
>>> By default, the CFA register is SP, however, it can be
>>> changed to any other.
>>>
>>> According to ARM's calling convention, the first eight
>>
>>Minor: s/ARM's/ARM (A64)'s/
>Fixed.
>>
>>> arguments of a function must be passed in x0-x7 registers,
>>> and all the remaining must be passed on the stack. The
>>> latter fact is important because it affects the SP and,
>>> because of that, the CFA invalidates. This patch changes
>>> the CFA register to the FP for the lj_vm_ffi_call, which
>>
>>Minor: should it be `lj_vm_ffi_call`?
>Fixed.
>>
>>> fixes the issue.
>>>
>>> All the other changes are made just for refactoring purposes.
>>>
>>> [1]:  https://dwarfstd.org/doc/DWARF5.pdf
>>>
>>> Maxim Kokryashkin:
>>> * added the description and the test case for the problem
>>>
>>> Needed for tarantool/tarantool#6096
>>> Part of tarantool/tarantool#7230
>>> ---
>>> src/lj_frame.h | 12 +-
>>> src/vm_arm64.dasc | 189 ++++++++++++++----
>>> .../lj-698-arm-pcall-panic.test.lua | 18 ++
>>> 3 files changed, 170 insertions(+), 49 deletions(-)
>>> create mode 100644 test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
>>>
>>> diff --git a/src/lj_frame.h b/src/lj_frame.h
>>> index 9fd63fa2..1e4adaa3 100644
>>> --- a/src/lj_frame.h
>>> +++ b/src/lj_frame.h
>>
>><snipped>
>>
>>> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
>>> index 313cc94f..ad57bca3 100644
>>> --- a/src/vm_arm64.dasc
>>> +++ b/src/vm_arm64.dasc
>>
>><snipped>
>>
>>> diff --git a/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua b/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
>>> new file mode 100644
>>> index 00000000..88476d3e
>>> --- /dev/null
>>> +++ b/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
>>> @@ -0,0 +1,18 @@
>>> +local tap = require('tap')
>>> +
>>> +-- See also  https://github.com/LuaJIT/LuaJIT/issues/698 .
>>> +local test = tap.test('lj-418-arm-pcall-panic')
>>
>>Typo: s/418/698/
>>Also, it is better to mention (in the test name too) LuaJIT/LuaJIT#722
>>issue (it's already mentioned in the commit message), at least it's
>>given an idea about reproducing:
>>https://github.com/LuaJIT/LuaJIT/issues/722
>Fixed.
>>
>>> +test:plan(1)
>>> +
>>> +local ffi = require('ffi')
>>> +-- The test case below was taken from the LuaJIT-tests
>>> +-- suite (lib/ffi/ffi_callback.lua), and should be removed
>>> +-- after the integration of the mentioned suite.
>>
>>Minor: I suppose that you mean "part of the suite".
>Fixed.
>>
>>> +local runner = ffi.cast("int (*)(int, int, int, int, int, int, int, int, int)",
>>
>>Minor: please use single quotes if it's possible.
>Fixed.
>>
>>> + function() error("test") end
>>> + )
>>
>>Nit: something strange with alignment. Can we just join these lines like
>>the follwing:
>>| local runner = ffi.cast('int (*)(int, int, int, int, int, int, int, int, int)',
>>| function() error('test') end)
>>
>>It's good to mention the rationale of the choice this amount of
>>arguments (just copying description from the commit message is enough).
>>
>>> +local st = pcall(runner, 1, 1, 1, 1, 1, 1, 1, 1, 1)
>>
>>Minor: should we check the error message too?
>>Feel free to ignore.
>>
>>> +test:ok(not st, 'error handling completed correctly')
>>> +
>>> +os.exit(test:check() and 0 or 1)
>>> --
>>> 2.37.0 (Apple Git-136)
>>>
>>
>>--
>>Best regards,
>>Sergey Kaplun
> 

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Re: [Tarantool-patches] [PATCH luajit v4 4/8] ARM64: Reorder interpreter stack frame and fix unwinding.

[sergos via Tarantool-patches]

Hi!

Thanks for the patch!

LGTM with fixes after SergeyK review.

Sergos


> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> From: Mike Pall <mike>
> 
> Reported by Yichun Zhang. Fixes #722.
> May help towards fixing #698, too.
> 
> (cherry picked from commit 421c4c798791d27b7f967df39891c4e4fa1d107c)
> 
> The `_Unwind_Find_FDE` fails to find the FDE (frame descriptor
> element) for `lj_vm_ffi_call` in DWARF unwind info, despite
> the presence of its data in the `.debug_frame` section.
> 
> LuaJIT emits its own DWARF entries for the CFI (call frame
> information, section 6.4.1 in DWARF standard)[1].The FP
> register value is vital to perform unwinding, and it is
> possible to restore that register using the Canonical
> Frame Address, or CFA. It can be obtained as `CFA - offset`.
> By default, the CFA register is SP, however, it can be
> changed to any other.
> 
> According to ARM's calling convention, the first eight
> arguments of a function must be passed in x0-x7 registers,
> and all the remaining must be passed on the stack. The
> latter fact is important because it affects the SP and,
> because of that, the CFA invalidates. This patch changes
> the CFA register to the FP for the lj_vm_ffi_call, which
> fixes the issue.
> 
> All the other changes are made just for refactoring purposes.
> 
> [1]: https://dwarfstd.org/doc/DWARF5.pdf
> 
> Maxim Kokryashkin:
> * added the description and the test case for the problem
> 
> Needed for tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
> src/lj_frame.h                                |  12 +-
> src/vm_arm64.dasc                             | 189 ++++++++++++++----
> .../lj-698-arm-pcall-panic.test.lua           |  18 ++
> 3 files changed, 170 insertions(+), 49 deletions(-)
> create mode 100644 test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
> 
> diff --git a/src/lj_frame.h b/src/lj_frame.h
> index 9fd63fa2..1e4adaa3 100644
> --- a/src/lj_frame.h
> +++ b/src/lj_frame.h
> @@ -192,12 +192,12 @@ enum { LJ_CONT_TAILCALL, LJ_CONT_FFI_CALLBACK };  /* Special continuations. */
> #endif
> #define CFRAME_SHIFT_MULTRES	3
> #elif LJ_TARGET_ARM64
> -#define CFRAME_OFS_ERRF		196
> -#define CFRAME_OFS_NRES		200
> -#define CFRAME_OFS_PREV		160
> -#define CFRAME_OFS_L		176
> -#define CFRAME_OFS_PC		168
> -#define CFRAME_OFS_MULTRES	192
> +#define CFRAME_OFS_ERRF		36
> +#define CFRAME_OFS_NRES		40
> +#define CFRAME_OFS_PREV		0
> +#define CFRAME_OFS_L		16
> +#define CFRAME_OFS_PC		8
> +#define CFRAME_OFS_MULTRES	32
> #define CFRAME_SIZE		208
> #define CFRAME_SHIFT_MULTRES	3
> #elif LJ_TARGET_PPC
> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
> index 313cc94f..ad57bca3 100644
> --- a/src/vm_arm64.dasc
> +++ b/src/vm_arm64.dasc
> @@ -81,47 +81,49 @@
> |
> |.define CFRAME_SPACE,	208
> |//----- 16 byte aligned, <-- sp entering interpreter
> -|// Unused		[sp, #204]	// 32 bit values
> -|.define SAVE_NRES,	[sp, #200]
> -|.define SAVE_ERRF,	[sp, #196]
> -|.define SAVE_MULTRES,	[sp, #192]
> -|.define TMPD,		[sp, #184]	// 64 bit values
> -|.define SAVE_L,	[sp, #176]
> -|.define SAVE_PC,	[sp, #168]
> -|.define SAVE_CFRAME,	[sp, #160]
> -|.define SAVE_FPR_,	96		// 96+8*8: 64 bit FPR saves
> -|.define SAVE_GPR_,	16		// 16+10*8: 64 bit GPR saves
> -|.define SAVE_LR,	[sp, #8]
> -|.define SAVE_FP,	[sp]
> +|.define SAVE_LR,	[sp, #200]
> +|.define SAVE_FP,	[sp, #192]
> +|.define SAVE_GPR_,	112		// 112+10*8: 64 bit GPR saves
> +|.define SAVE_FPR_,	48		// 48+8*8: 64 bit FPR saves
> +|// Unused		[sp, #44]	// 32 bit values
> +|.define SAVE_NRES,	[sp, #40]
> +|.define SAVE_ERRF,	[sp, #36]
> +|.define SAVE_MULTRES,	[sp, #32]
> +|.define TMPD,		[sp, #24]	// 64 bit values
> +|.define SAVE_L,	[sp, #16]
> +|.define SAVE_PC,	[sp, #8]
> +|.define SAVE_CFRAME,	[sp, #0]
> |//----- 16 byte aligned, <-- sp while in interpreter.
> |
> -|.define TMPDofs,	#184
> +|.define TMPDofs,	#24
> |
> |.macro save_, gpr1, gpr2, fpr1, fpr2
> -|  stp d..fpr1, d..fpr2, [sp, # SAVE_FPR_+(fpr1-8)*8]
> -|  stp x..gpr1, x..gpr2, [sp, # SAVE_GPR_+(gpr1-19)*8]
> +|  stp d..fpr2, d..fpr1, [sp, # SAVE_FPR_+(14-fpr1)*8]
> +|  stp x..gpr2, x..gpr1, [sp, # SAVE_GPR_+(27-gpr1)*8]
> |.endmacro
> |.macro rest_, gpr1, gpr2, fpr1, fpr2
> -|  ldp d..fpr1, d..fpr2, [sp, # SAVE_FPR_+(fpr1-8)*8]
> -|  ldp x..gpr1, x..gpr2, [sp, # SAVE_GPR_+(gpr1-19)*8]
> +|  ldp d..fpr2, d..fpr1, [sp, # SAVE_FPR_+(14-fpr1)*8]
> +|  ldp x..gpr2, x..gpr1, [sp, # SAVE_GPR_+(27-gpr1)*8]
> |.endmacro
> |
> |.macro saveregs
> -|  stp fp, lr, [sp, #-CFRAME_SPACE]!
> +|  sub sp, sp, # CFRAME_SPACE
> +|  stp fp, lr, SAVE_FP
> |  add fp, sp, #0
> -|  stp x19, x20, [sp, # SAVE_GPR_]
> +|  stp x20, x19, [sp, # SAVE_GPR_+(27-19)*8]
> |  save_ 21, 22, 8, 9
> |  save_ 23, 24, 10, 11
> |  save_ 25, 26, 12, 13
> |  save_ 27, 28, 14, 15
> |.endmacro
> |.macro restoreregs
> -|  ldp x19, x20, [sp, # SAVE_GPR_]
> +|  ldp x20, x19, [sp, # SAVE_GPR_+(27-19)*8]
> |  rest_ 21, 22, 8, 9
> |  rest_ 23, 24, 10, 11
> |  rest_ 25, 26, 12, 13
> |  rest_ 27, 28, 14, 15
> -|  ldp fp, lr, [sp], # CFRAME_SPACE
> +|  ldp fp, lr, SAVE_FP
> +|  add sp, sp, # CFRAME_SPACE
> |.endmacro
> |
> |// Type definitions. Some of these are only used for documentation.
> @@ -2125,9 +2127,9 @@ static void build_subroutines(BuildCtx *ctx)
>   |  // Caveat: needs special frame unwinding, see below.
>   |.if FFI
>   |  .type CCSTATE, CCallState, x19
> -  |  stp fp, lr, [sp, #-32]!
> +  |  stp x20, CCSTATE, [sp, #-32]!
> +  |  stp fp, lr, [sp, #16]
>   |  add fp, sp, #0
> -  |  str CCSTATE, [sp, #16]
>   |  mov CCSTATE, x0
>   |  ldr TMP0w, CCSTATE:x0->spadj
>   |   ldrb TMP1w, CCSTATE->nsp
> @@ -2156,8 +2158,8 @@ static void build_subroutines(BuildCtx *ctx)
>   |  stp x0, x1, CCSTATE->gpr[0]
>   |   stp d0, d1, CCSTATE->fpr[0]
>   |   stp d2, d3, CCSTATE->fpr[2]
> -  |  ldr CCSTATE, [sp, #16]
> -  |  ldp fp, lr, [sp], #32
> +  |  ldp fp, lr, [sp, #16]
> +  |  ldp x20, CCSTATE, [sp], #32
>   |  ret
>   |.endif
>   |// Note: vm_ffi_call must be the last function in this object file!
> @@ -2887,7 +2889,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
>   case BC_GGET:
>     |  // RA = dst, RC = str_const (~)
>   case BC_GSET:
> -    |  // RA = dst, RC = str_const (~)
> +    |  // RA = src, RC = str_const (~)
>     |  ldr LFUNC:CARG1, [BASE, FRAME_FUNC]
>     |   mvn RC, RC
>     |  and LFUNC:CARG1, CARG1, #LJ_GCVMASK
> @@ -3863,7 +3865,7 @@ static int build_backend(BuildCtx *ctx)
> static void emit_asm_debug(BuildCtx *ctx)
> {
>   int fcofs = (int)((uint8_t *)ctx->glob[GLOB_vm_ffi_call] - ctx->code);
> -  int i, cf = CFRAME_SIZE >> 3;
> +  int i;
>   switch (ctx->mode) {
>   case BUILD_elfasm:
>     fprintf(ctx->fp, "\t.section .debug_frame,\"\",%%progbits\n");
> @@ -3888,14 +3890,14 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.quad .Lbegin\n"
> 	"\t.quad %d\n"
> 	"\t.byte 0xe\n\t.uleb128 %d\n"		/* def_cfa_offset */
> -	"\t.byte 0x9d\n\t.uleb128 %d\n"		/* offset fp */
> -	"\t.byte 0x9e\n\t.uleb128 %d\n",	/* offset lr */
> -	fcofs, CFRAME_SIZE, cf, cf-1);
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> +	fcofs, CFRAME_SIZE);
>     for (i = 19; i <= 28; i++)  /* offset x19-x28 */
> -      fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, cf-i+17);
> +      fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>     for (i = 8; i <= 15; i++)  /* offset d8-d15 */
>       fprintf(ctx->fp, "\t.byte 5\n\t.uleb128 0x%x\n\t.uleb128 %d\n",
> -	      64+i, cf-i-4);
> +	      64+i, i+(3+(28-19+1)-8));
>     fprintf(ctx->fp,
> 	"\t.align 3\n"
> 	".LEFDE0:\n\n");
> @@ -3908,9 +3910,11 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.quad lj_vm_ffi_call\n"
> 	"\t.quad %d\n"
> 	"\t.byte 0xe\n\t.uleb128 32\n"		/* def_cfa_offset */
> -	"\t.byte 0x9d\n\t.uleb128 4\n"		/* offset fp */
> -	"\t.byte 0x9e\n\t.uleb128 3\n"		/* offset lr */
> -	"\t.byte 0x93\n\t.uleb128 2\n"		/* offset x19 */
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
> +	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
> +	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
> +	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
> 	"\t.align 3\n"
> 	".LEFDE1:\n\n", (int)ctx->codesz - fcofs);
> #endif
> @@ -3941,14 +3945,14 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long %d\n"
> 	"\t.uleb128 0\n"			/* augmentation length */
> 	"\t.byte 0xe\n\t.uleb128 %d\n"		/* def_cfa_offset */
> -	"\t.byte 0x9d\n\t.uleb128 %d\n"		/* offset fp */
> -	"\t.byte 0x9e\n\t.uleb128 %d\n",	/* offset lr */
> -	fcofs, CFRAME_SIZE, cf, cf-1);
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> +	fcofs, CFRAME_SIZE);
>     for (i = 19; i <= 28; i++)  /* offset x19-x28 */
> -      fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, cf-i+17);
> +      fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>     for (i = 8; i <= 15; i++)  /* offset d8-d15 */
>       fprintf(ctx->fp, "\t.byte 5\n\t.uleb128 0x%x\n\t.uleb128 %d\n",
> -	      64+i, cf-i-4);
> +	      64+i, i+(3+(28-19+1)-8));
>     fprintf(ctx->fp,
> 	"\t.align 3\n"
> 	".LEFDE2:\n\n");
> @@ -3977,13 +3981,112 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long %d\n"
> 	"\t.uleb128 0\n"			/* augmentation length */
> 	"\t.byte 0xe\n\t.uleb128 32\n"		/* def_cfa_offset */
> -	"\t.byte 0x9d\n\t.uleb128 4\n"		/* offset fp */
> -	"\t.byte 0x9e\n\t.uleb128 3\n"		/* offset lr */
> -	"\t.byte 0x93\n\t.uleb128 2\n"		/* offset x19 */
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
> +	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
> +	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
> +	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
> 	"\t.align 3\n"
> 	".LEFDE3:\n\n", (int)ctx->codesz - fcofs);
> #endif
>     break;
> +#if !LJ_NO_UNWIND
> +  case BUILD_machasm: {
> +#if LJ_HASFFI
> +    int fcsize = 0;
> +#endif
> +    int j;
> +    fprintf(ctx->fp, "\t.section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support\n");
> +    fprintf(ctx->fp,
> +	"EH_frame1:\n"
> +	"\t.set L$set$x,LECIEX-LSCIEX\n"
> +	"\t.long L$set$x\n"
> +	"LSCIEX:\n"
> +	"\t.long 0\n"
> +	"\t.byte 0x1\n"
> +	"\t.ascii \"zPR\\0\"\n"
> +	"\t.byte 0x1\n"
> +	"\t.byte 128-8\n"
> +	"\t.byte 30\n"				/* Return address is in lr. */
> +	"\t.byte 6\n"				/* augmentation length */
> +	"\t.byte 0x9b\n"			/* indirect|pcrel|sdata4 */
> +	"\t.long _lj_err_unwind_dwarf@GOTPCREL\n"
> +	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> +	"\t.byte 0xc\n\t.byte 31\n\t.byte 0\n"	/* def_cfa sp */
> +	"\t.align 3\n"
> +	"LECIEX:\n\n");
> +    for (j = 0; j < ctx->nsym; j++) {
> +      const char *name = ctx->sym[j].name;
> +      int32_t size = ctx->sym[j+1].ofs - ctx->sym[j].ofs;
> +      if (size == 0) continue;
> +#if LJ_HASFFI
> +      if (!strcmp(name, "_lj_vm_ffi_call")) { fcsize = size; continue; }
> +#endif
> +      fprintf(ctx->fp,
> +	"%s.eh:\n"
> +	"LSFDE%d:\n"
> +	"\t.set L$set$%d,LEFDE%d-LASFDE%d\n"
> +	"\t.long L$set$%d\n"
> +	"LASFDE%d:\n"
> +	"\t.long LASFDE%d-EH_frame1\n"
> +	"\t.long %s-.\n"
> +	"\t.long %d\n"
> +	"\t.byte 0\n"				/* augmentation length */
> +	"\t.byte 0xe\n\t.byte %d\n\t.byte 1\n"	/* def_cfa_offset */
> +	"\t.byte 0x9e\n\t.byte 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.byte 2\n",		/* offset fp */
> +	name, j, j, j, j, j, j, j, name, size, CFRAME_SIZE);
> +      for (i = 19; i <= 28; i++)  /* offset x19-x28 */
> +	fprintf(ctx->fp, "\t.byte 0x%x\n\t.byte %d\n", 0x80+i, i+(3-19));
> +      for (i = 8; i <= 15; i++)  /* offset d8-d15 */
> +	fprintf(ctx->fp, "\t.byte 5\n\t.byte 0x%x\n\t.byte %d\n",
> +		64+i, i+(3+(28-19+1)-8));
> +      fprintf(ctx->fp,
> +	"\t.align 3\n"
> +	"LEFDE%d:\n\n", j);
> +    }
> +#if LJ_HASFFI
> +    if (fcsize) {
> +      fprintf(ctx->fp,
> +	"EH_frame2:\n"
> +	"\t.set L$set$y,LECIEY-LSCIEY\n"
> +	"\t.long L$set$y\n"
> +	"LSCIEY:\n"
> +	"\t.long 0\n"
> +	"\t.byte 0x1\n"
> +	"\t.ascii \"zR\\0\"\n"
> +	"\t.byte 0x1\n"
> +	"\t.byte 128-8\n"
> +	"\t.byte 30\n"				/* Return address is in lr. */
> +	"\t.byte 1\n"				/* augmentation length */
> +	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> +	"\t.byte 0xc\n\t.byte 31\n\t.byte 0\n"	/* def_cfa sp */
> +	"\t.align 3\n"
> +	"LECIEY:\n\n");
> +      fprintf(ctx->fp,
> +	"_lj_vm_ffi_call.eh:\n"
> +	"LSFDEY:\n"
> +	"\t.set L$set$yy,LEFDEY-LASFDEY\n"
> +	"\t.long L$set$yy\n"
> +	"LASFDEY:\n"
> +	"\t.long LASFDEY-EH_frame2\n"
> +	"\t.long _lj_vm_ffi_call-.\n"
> +	"\t.long %d\n"
> +	"\t.byte 0\n"				/* augmentation length */
> +	"\t.byte 0xe\n\t.byte 32\n"		/* def_cfa_offset */
> +	"\t.byte 0x9e\n\t.byte 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.byte 2\n"		/* offset fp */
> +	"\t.byte 0x93\n\t.byte 3\n"		/* offset x19 */
> +	"\t.byte 0x94\n\t.byte 4\n"		/* offset x20 */
> +	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
> +	"\t.align 3\n"
> +	"LEFDEY:\n\n", fcsize);
> +    }
> +#endif
> +    fprintf(ctx->fp, ".subsections_via_symbols\n");
> +    }
> +    break;
> +#endif
>   default:
>     break;
>   }
> diff --git a/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua b/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
> new file mode 100644
> index 00000000..88476d3e
> --- /dev/null
> +++ b/test/tarantool-tests/lj-698-arm-pcall-panic.test.lua
> @@ -0,0 +1,18 @@
> +local tap = require('tap')
> +
> +-- See also https://github.com/LuaJIT/LuaJIT/issues/698.
> +local test = tap.test('lj-418-arm-pcall-panic')
> +test:plan(1)
> +
> +local ffi = require('ffi')
> +-- The test case below was taken from the LuaJIT-tests
> +-- suite (lib/ffi/ffi_callback.lua), and should be removed
> +-- after the integration of the mentioned suite.
> +local runner = ffi.cast("int (*)(int, int, int, int, int, int, int, int, int)",
> +                        function() error("test") end
> +                      )
> +
> +local st = pcall(runner, 1, 1, 1, 1, 1, 1, 1, 1, 1)
> +test:ok(not st, 'error handling completed correctly')
> +
> +os.exit(test:check() and 0 or 1)
> -- 
> 2.37.0 (Apple Git-136)
> 

Re: [Tarantool-patches] [PATCH luajit v4 8/8] OSX/ARM64: Fix external unwinding.

[Sergey Kaplun via Tarantool-patches]

Hi, Maksim!

Thanks for the patch!

LGTM, but I have a bunch of questions to clarify it.

On 28.10.22, Maksim Kokryashkin wrote:
> Contributed by Edmund Kapusniak. For more info,
> see #698 and #757.
> 
> (cherry picked from commit c38747b626b978555324504ec29a110f6b04902f)
> 
> To allow compiler generate compact unwind info generation
> for Mach-O, fp must point to the saved fp, and the frame
> must be specified relative to fp+16.

Is there any link to documentation or source code to inspect this
behaviour?

>                                      ELF unwind info has
> been updated to also use fp+16 rather than sp+CFRAME_SIZE.

Also, I see that `.byte` notation is replaced with `.uleb128` or
`.sleb128`. What is the reason?
Same question for removing names of entries ("_lj_vm_ffi_call.eh:" for
example).

> 
> Offset to pointer to personality routine specified as @GOT-. rather
> than @GOTPCREL.

Does it mean that we use incorrect encoded offset (I see encoding for
offset is still the same) for our personality routine?
If so, maybe the other changes are just refactoring?

> 
> Re-enabled LUAJIT_UNWIND_EXTERNAL by default on OSX.
> 
> Maxim Kokryashkin:
> * added the description for the issue and the test
> 
> Resolves tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
>  cmake/SetTargetFlags.cmake                    |  4 +-
>  src/Makefile.original                         |  5 +-
>  src/vm_arm64.dasc                             | 89 ++++++++-----------
>  ...-6096-external-unwinding-on-arm64.test.lua | 13 +++
>  4 files changed, 54 insertions(+), 57 deletions(-)
>  create mode 100644 test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index 8abb6288..7cf26be1 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake

<snipped>

> diff --git a/src/Makefile.original b/src/Makefile.original
> index 2d014e43..813d9c12 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original

<snipped>

> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
> index ccfa72bd..f517a808 100644
> --- a/src/vm_arm64.dasc
> +++ b/src/vm_arm64.dasc

<snipped>

> @@ -504,8 +503,9 @@ static void build_subroutines(BuildCtx *ctx)
>    |    ldr GL, L->glref			// Setup pointer to global state.
>    |     mov BASE, CARG2
>    |   str CARG1, SAVE_PC		// Any value outside of bytecode is ok.
> -  |  str RC, SAVE_CFRAME
> -  |  str fp, L->cframe			// Add our C frame to cframe chain.
> +  |  add TMP0, sp, #0
> +  |   str RC, SAVE_CFRAME
> +  |  str TMP0, L->cframe		// Add our C frame to cframe chain.

Why can't we just use the following?
|  str RC, SAVE_CFRAME
|  str sp, L->cframe			// Add our C frame to cframe chain.

>    |
>    |3:  // Entry point for vm_cpcall/vm_resume (BASE = base, PC = ftype).
>    |  str L, GL->cur_L
> @@ -540,8 +540,9 @@ static void build_subroutines(BuildCtx *ctx)
>    |   sub RA, RA, RB			// Compute -savestack(L, L->top).
>    |   str RAw, SAVE_NRES		// Neg. delta means cframe w/o frame.
>    |  str wzr, SAVE_ERRF			// No error function.
> -  |  str RC, SAVE_CFRAME
> -  |  str fp, L->cframe			// Add our C frame to cframe chain.
> +  |  add TMP0, sp, #0
> +  |   str RC, SAVE_CFRAME
> +  |  str TMP0, L->cframe		// Add our C frame to cframe chain.

Ditto.

>    |    str L, GL->cur_L
>    |  blr CARG4			// (lua_State *L, lua_CFunction func, void *ud)
>    |  mov BASE, CRET1
> @@ -2129,14 +2130,14 @@ static void build_subroutines(BuildCtx *ctx)

<snipped>

> @@ -3879,7 +3880,7 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.uleb128 0x1\n"
>  	"\t.sleb128 -8\n"
>  	"\t.byte 30\n"				/* Return address is in lr. */
> -	"\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
>  	"\t.align 3\n"
>  	".LECIE0:\n\n");
>      fprintf(ctx->fp,
> @@ -3889,10 +3890,9 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long .Lframe0\n"
>  	"\t.quad .Lbegin\n"
>  	"\t.quad %d\n"
> -	"\t.byte 0xe\n\t.uleb128 %d\n"		/* def_cfa_offset */
>  	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
>  	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> -	fcofs, CFRAME_SIZE);
> +	fcofs);
>      for (i = 19; i <= 28; i++)  /* offset x19-x28 */
>        fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>      for (i = 8; i <= 15; i++)  /* offset d8-d15 */
> @@ -3909,12 +3909,10 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long .Lframe0\n"
>  	"\t.quad lj_vm_ffi_call\n"
>  	"\t.quad %d\n"
> -	"\t.byte 0xe\n\t.uleb128 32\n"		/* def_cfa_offset */
>  	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
>  	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
>  	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
>  	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
> -	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
>  	"\t.align 3\n"
>  	".LEFDE1:\n\n", (int)ctx->codesz - fcofs);
>  #endif
> @@ -3933,7 +3931,7 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
>  	"\t.long lj_err_unwind_dwarf-.\n"
>  	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
>  	"\t.align 3\n"
>  	".LECIE1:\n\n");
>      fprintf(ctx->fp,
> @@ -3944,10 +3942,9 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long .Lbegin-.\n"
>  	"\t.long %d\n"
>  	"\t.uleb128 0\n"			/* augmentation length */
> -	"\t.byte 0xe\n\t.uleb128 %d\n"		/* def_cfa_offset */
>  	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
>  	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> -	fcofs, CFRAME_SIZE);
> +	fcofs);
>      for (i = 19; i <= 28; i++)  /* offset x19-x28 */
>        fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>      for (i = 8; i <= 15; i++)  /* offset d8-d15 */
> @@ -3969,7 +3966,7 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.byte 30\n"				/* Return address is in lr. */
>  	"\t.uleb128 1\n"			/* augmentation length */
>  	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
>  	"\t.align 3\n"
>  	".LECIE2:\n\n");
>      fprintf(ctx->fp,
> @@ -3980,18 +3977,15 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long lj_vm_ffi_call-.\n"
>  	"\t.long %d\n"
>  	"\t.uleb128 0\n"			/* augmentation length */
> -	"\t.byte 0xe\n\t.uleb128 32\n"		/* def_cfa_offset */
>  	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
>  	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
>  	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
>  	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
> -	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
>  	"\t.align 3\n"
>  	".LEFDE3:\n\n", (int)ctx->codesz - fcofs);
>  #endif
>      break;
> -    /* Disabled until someone finds a fix. See #698. */
> -#if !LJ_NO_UNWIND && 0
> +#if !LJ_NO_UNWIND
>    case BUILD_machasm: {
>  #if LJ_HASFFI
>      int fcsize = 0;
> @@ -4006,14 +4000,14 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long 0\n"
>  	"\t.byte 0x1\n"
>  	"\t.ascii \"zPR\\0\"\n"
> -	"\t.byte 0x1\n"
> -	"\t.byte 128-8\n"
> +	"\t.uleb128 0x1\n"
> +	"\t.sleb128 -8\n"
>  	"\t.byte 30\n"				/* Return address is in lr. */
> -	"\t.byte 6\n"				/* augmentation length */
> +	"\t.uleb128 6\n"			/* augmentation length */
>  	"\t.byte 0x9b\n"			/* indirect|pcrel|sdata4 */
> -	"\t.long _lj_err_unwind_dwarf@GOTPCREL\n"
> +	"\t.long _lj_err_unwind_dwarf@GOT-.\n"
>  	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.byte 31\n\t.byte 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
>  	"\t.align 3\n"
>  	"LECIEX:\n\n");
>      for (j = 0; j < ctx->nsym; j++) {
> @@ -4024,7 +4018,6 @@ static void emit_asm_debug(BuildCtx *ctx)
>        if (!strcmp(name, "_lj_vm_ffi_call")) { fcsize = size; continue; }
>  #endif
>        fprintf(ctx->fp,
> -	"%s.eh:\n"
>  	"LSFDE%d:\n"
>  	"\t.set L$set$%d,LEFDE%d-LASFDE%d\n"
>  	"\t.long L$set$%d\n"
> @@ -4032,15 +4025,14 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long LASFDE%d-EH_frame1\n"
>  	"\t.long %s-.\n"
>  	"\t.long %d\n"
> -	"\t.byte 0\n"				/* augmentation length */
> -	"\t.byte 0xe\n\t.byte %d\n\t.byte 1\n"	/* def_cfa_offset */
> -	"\t.byte 0x9e\n\t.byte 1\n"		/* offset lr */
> -	"\t.byte 0x9d\n\t.byte 2\n",		/* offset fp */
> -	name, j, j, j, j, j, j, j, name, size, CFRAME_SIZE);
> +	"\t.uleb128 0\n"			/* augmentation length */
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> +	j, j, j, j, j, j, j, name, size);
>        for (i = 19; i <= 28; i++)  /* offset x19-x28 */
> -	fprintf(ctx->fp, "\t.byte 0x%x\n\t.byte %d\n", 0x80+i, i+(3-19));
> +	fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>        for (i = 8; i <= 15; i++)  /* offset d8-d15 */
> -	fprintf(ctx->fp, "\t.byte 5\n\t.byte 0x%x\n\t.byte %d\n",
> +	fprintf(ctx->fp, "\t.byte 5\n\t.uleb128 0x%x\n\t.uleb128 %d\n",
>  		64+i, i+(3+(28-19+1)-8));
>        fprintf(ctx->fp,
>  	"\t.align 3\n"
> @@ -4056,16 +4048,15 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long 0\n"
>  	"\t.byte 0x1\n"
>  	"\t.ascii \"zR\\0\"\n"
> -	"\t.byte 0x1\n"
> -	"\t.byte 128-8\n"
> +	"\t.uleb128 0x1\n"
> +	"\t.sleb128 -8\n"
>  	"\t.byte 30\n"				/* Return address is in lr. */
> -	"\t.byte 1\n"				/* augmentation length */
> +	"\t.uleb128 1\n"			/* augmentation length */
>  	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.byte 31\n\t.byte 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
>  	"\t.align 3\n"
>  	"LECIEY:\n\n");
>        fprintf(ctx->fp,
> -	"_lj_vm_ffi_call.eh:\n"
>  	"LSFDEY:\n"
>  	"\t.set L$set$yy,LEFDEY-LASFDEY\n"
>  	"\t.long L$set$yy\n"
> @@ -4073,13 +4064,11 @@ static void emit_asm_debug(BuildCtx *ctx)
>  	"\t.long LASFDEY-EH_frame2\n"
>  	"\t.long _lj_vm_ffi_call-.\n"
>  	"\t.long %d\n"
> -	"\t.byte 0\n"				/* augmentation length */
> -	"\t.byte 0xe\n\t.byte 32\n"		/* def_cfa_offset */
> -	"\t.byte 0x9e\n\t.byte 1\n"		/* offset lr */
> -	"\t.byte 0x9d\n\t.byte 2\n"		/* offset fp */
> -	"\t.byte 0x93\n\t.byte 3\n"		/* offset x19 */
> -	"\t.byte 0x94\n\t.byte 4\n"		/* offset x20 */
> -	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
> +	"\t.uleb128 0\n"			/* augmentation length */
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
> +	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
> +	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
>  	"\t.align 3\n"
>  	"LEFDEY:\n\n", fcsize);
>      }
> diff --git a/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua b/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
> new file mode 100644
> index 00000000..cdeea441
> --- /dev/null
> +++ b/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua

<snipped>

> -- 
> 2.37.0 (Apple Git-136)
> 

-- 
Best regards,
Sergey Kaplun

Re: [Tarantool-patches] [PATCH luajit v4 8/8] OSX/ARM64: Fix external unwinding.

[Maxim Kokryashkin via Tarantool-patches]

[-- Attachment #1: Type: text/plain, Size: 12181 bytes --]


Hi!
Thanks for the review!
 
> 
>>Hi, Maksim!
>>
>>Thanks for the patch!
>>
>>LGTM, but I have a bunch of questions to clarify it.
>>
>>On 28.10.22, Maksim Kokryashkin wrote:
>>> Contributed by Edmund Kapusniak. For more info,
>>> see #698 and #757.
>>>
>>> (cherry picked from commit c38747b626b978555324504ec29a110f6b04902f)
>>>
>>> To allow compiler generate compact unwind info generation
>>> for Mach-O, fp must point to the saved fp, and the frame
>>> must be specified relative to fp+16.
>>
>>Is there any link to documentation or source code to inspect this
>>behaviour?
>Unfortunately, there are no official docs for that. However, there is
>a community effort to create one here[1]. Also, this header file from
>the Apple’s sources is quite useful. Added both of them to commit
>message for those who will get the masculine urge to dive into this.
>>
>>> ELF unwind info has
>>> been updated to also use fp+16 rather than sp+CFRAME_SIZE.
>>
>>Also, I see that `.byte` notation is replaced with `.uleb128` or
>>`.sleb128`. What is the reason?
>>Same question for removing names of entries ("_lj_vm_ffi_call.eh:" for
>>example).
>IINM, it is something Apple expects from the compact unwind info[2].
>>
>>>
>>> Offset to pointer to personality routine specified as @GOT-. rather
>>> than @GOTPCREL.
>>
>>Does it mean that we use incorrect encoded offset (I see encoding for
>>offset is still the same) for our personality routine?
>>If so, maybe the other changes are just refactoring?
>No, that is not correct. Offset has changed, because any 
>`func@GOT` expression is translated into offset.
>Moreover, I doubt it is possible to fill in offset to GOT by hand.
>What goes after the pointer to the personality routine
>is LSDA, according to the Apple’s source[2]. @GOTPCREL and @GOT
>are interchangeable most of the time, except for the cases when signed
>32-bit RIP references are not enough for you, which seems to be the case here.
>>
>>>
>>> Re-enabled LUAJIT_UNWIND_EXTERNAL by default on OSX.
>>>
>>> Maxim Kokryashkin:
>>> * added the description for the issue and the test
>>>
>>> Resolves tarantool/tarantool#6096
>>> Part of tarantool/tarantool#7230
>>> ---
>>> cmake/SetTargetFlags.cmake | 4 +-
>>> src/Makefile.original | 5 +-
>>> src/vm_arm64.dasc | 89 ++++++++-----------
>>> ...-6096-external-unwinding-on-arm64.test.lua | 13 +++
>>> 4 files changed, 54 insertions(+), 57 deletions(-)
>>> create mode 100644 test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
>>>
>>> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
>>> index 8abb6288..7cf26be1 100644
>>> --- a/cmake/SetTargetFlags.cmake
>>> +++ b/cmake/SetTargetFlags.cmake
>>
>><snipped>
>>
>>> diff --git a/src/Makefile.original b/src/Makefile.original
>>> index 2d014e43..813d9c12 100644
>>> --- a/src/Makefile.original
>>> +++ b/src/Makefile.original
>>
>><snipped>
>>
>>> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
>>> index ccfa72bd..f517a808 100644
>>> --- a/src/vm_arm64.dasc
>>> +++ b/src/vm_arm64.dasc
>>
>><snipped>
>>
>>> @@ -504,8 +503,9 @@ static void build_subroutines(BuildCtx *ctx)
>>> | ldr GL, L->glref // Setup pointer to global state.
>>> | mov BASE, CARG2
>>> | str CARG1, SAVE_PC // Any value outside of bytecode is ok.
>>> - | str RC, SAVE_CFRAME
>>> - | str fp, L->cframe // Add our C frame to cframe chain.
>>> + | add TMP0, sp, #0
>>> + | str RC, SAVE_CFRAME
>>> + | str TMP0, L->cframe // Add our C frame to cframe chain.
>>
>>Why can't we just use the following?
>>| str RC, SAVE_CFRAME
>>| str sp, L->cframe // Add our C frame to cframe chain.
>>
>>> |
>>> |3: // Entry point for vm_cpcall/vm_resume (BASE = base, PC = ftype).
>>> | str L, GL->cur_L
>>> @@ -540,8 +540,9 @@ static void build_subroutines(BuildCtx *ctx)
>>> | sub RA, RA, RB // Compute -savestack(L, L->top).
>>> | str RAw, SAVE_NRES // Neg. delta means cframe w/o frame.
>>> | str wzr, SAVE_ERRF // No error function.
>>> - | str RC, SAVE_CFRAME
>>> - | str fp, L->cframe // Add our C frame to cframe chain.
>>> + | add TMP0, sp, #0
>>> + | str RC, SAVE_CFRAME
>>> + | str TMP0, L->cframe // Add our C frame to cframe chain.
>>
>>Ditto.
>>
>>> | str L, GL->cur_L
>>> | blr CARG4 // (lua_State *L, lua_CFunction func, void *ud)
>>> | mov BASE, CRET1
>>> @@ -2129,14 +2130,14 @@ static void build_subroutines(BuildCtx *ctx)
>>
>><snipped>
>>
>>> @@ -3879,7 +3880,7 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.uleb128 0x1\n"
>>> "\t.sleb128 -8\n"
>>> "\t.byte 30\n" /* Return address is in lr. */
>>> - "\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n" /* def_cfa sp */
>>> + "\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n" /* def_cfa fp 16 */
>>> "\t.align 3\n"
>>> ".LECIE0:\n\n");
>>> fprintf(ctx->fp,
>>> @@ -3889,10 +3890,9 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long .Lframe0\n"
>>> "\t.quad .Lbegin\n"
>>> "\t.quad %d\n"
>>> - "\t.byte 0xe\n\t.uleb128 %d\n" /* def_cfa_offset */
>>> "\t.byte 0x9e\n\t.uleb128 1\n" /* offset lr */
>>> "\t.byte 0x9d\n\t.uleb128 2\n", /* offset fp */
>>> - fcofs, CFRAME_SIZE);
>>> + fcofs);
>>> for (i = 19; i <= 28; i++) /* offset x19-x28 */
>>> fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>>> for (i = 8; i <= 15; i++) /* offset d8-d15 */
>>> @@ -3909,12 +3909,10 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long .Lframe0\n"
>>> "\t.quad lj_vm_ffi_call\n"
>>> "\t.quad %d\n"
>>> - "\t.byte 0xe\n\t.uleb128 32\n" /* def_cfa_offset */
>>> "\t.byte 0x9e\n\t.uleb128 1\n" /* offset lr */
>>> "\t.byte 0x9d\n\t.uleb128 2\n" /* offset fp */
>>> "\t.byte 0x93\n\t.uleb128 3\n" /* offset x19 */
>>> "\t.byte 0x94\n\t.uleb128 4\n" /* offset x20 */
>>> - "\t.byte 0xd\n\t.uleb128 0x1d\n" /* def_cfa_register fp */
>>> "\t.align 3\n"
>>> ".LEFDE1:\n\n", (int)ctx->codesz - fcofs);
>>> #endif
>>> @@ -3933,7 +3931,7 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.byte 0x1b\n" /* pcrel|sdata4 */
>>> "\t.long lj_err_unwind_dwarf-.\n"
>>> "\t.byte 0x1b\n" /* pcrel|sdata4 */
>>> - "\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n" /* def_cfa sp */
>>> + "\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n" /* def_cfa fp 16 */
>>> "\t.align 3\n"
>>> ".LECIE1:\n\n");
>>> fprintf(ctx->fp,
>>> @@ -3944,10 +3942,9 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long .Lbegin-.\n"
>>> "\t.long %d\n"
>>> "\t.uleb128 0\n" /* augmentation length */
>>> - "\t.byte 0xe\n\t.uleb128 %d\n" /* def_cfa_offset */
>>> "\t.byte 0x9e\n\t.uleb128 1\n" /* offset lr */
>>> "\t.byte 0x9d\n\t.uleb128 2\n", /* offset fp */
>>> - fcofs, CFRAME_SIZE);
>>> + fcofs);
>>> for (i = 19; i <= 28; i++) /* offset x19-x28 */
>>> fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>>> for (i = 8; i <= 15; i++) /* offset d8-d15 */
>>> @@ -3969,7 +3966,7 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.byte 30\n" /* Return address is in lr. */
>>> "\t.uleb128 1\n" /* augmentation length */
>>> "\t.byte 0x1b\n" /* pcrel|sdata4 */
>>> - "\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n" /* def_cfa sp */
>>> + "\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n" /* def_cfa fp 16 */
>>> "\t.align 3\n"
>>> ".LECIE2:\n\n");
>>> fprintf(ctx->fp,
>>> @@ -3980,18 +3977,15 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long lj_vm_ffi_call-.\n"
>>> "\t.long %d\n"
>>> "\t.uleb128 0\n" /* augmentation length */
>>> - "\t.byte 0xe\n\t.uleb128 32\n" /* def_cfa_offset */
>>> "\t.byte 0x9e\n\t.uleb128 1\n" /* offset lr */
>>> "\t.byte 0x9d\n\t.uleb128 2\n" /* offset fp */
>>> "\t.byte 0x93\n\t.uleb128 3\n" /* offset x19 */
>>> "\t.byte 0x94\n\t.uleb128 4\n" /* offset x20 */
>>> - "\t.byte 0xd\n\t.uleb128 0x1d\n" /* def_cfa_register fp */
>>> "\t.align 3\n"
>>> ".LEFDE3:\n\n", (int)ctx->codesz - fcofs);
>>> #endif
>>> break;
>>> - /* Disabled until someone finds a fix. See #698. */
>>> -#if !LJ_NO_UNWIND && 0
>>> +#if !LJ_NO_UNWIND
>>> case BUILD_machasm: {
>>> #if LJ_HASFFI
>>> int fcsize = 0;
>>> @@ -4006,14 +4000,14 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long 0\n"
>>> "\t.byte 0x1\n"
>>> "\t.ascii \"zPR\\0\"\n"
>>> - "\t.byte 0x1\n"
>>> - "\t.byte 128-8\n"
>>> + "\t.uleb128 0x1\n"
>>> + "\t.sleb128 -8\n"
>>> "\t.byte 30\n" /* Return address is in lr. */
>>> - "\t.byte 6\n" /* augmentation length */
>>> + "\t.uleb128 6\n" /* augmentation length */
>>> "\t.byte 0x9b\n" /* indirect|pcrel|sdata4 */
>>> - "\t.long _lj_err_unwind_dwarf@GOTPCREL\n"
>>> + "\t.long _lj_err_unwind_dwarf@GOT-.\n"
>>> "\t.byte 0x1b\n" /* pcrel|sdata4 */
>>> - "\t.byte 0xc\n\t.byte 31\n\t.byte 0\n" /* def_cfa sp */
>>> + "\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n" /* def_cfa fp 16 */
>>> "\t.align 3\n"
>>> "LECIEX:\n\n");
>>> for (j = 0; j < ctx->nsym; j++) {
>>> @@ -4024,7 +4018,6 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> if (!strcmp(name, "_lj_vm_ffi_call")) { fcsize = size; continue; }
>>> #endif
>>> fprintf(ctx->fp,
>>> - "%s.eh:\n"
>>> "LSFDE%d:\n"
>>> "\t.set L$set$%d,LEFDE%d-LASFDE%d\n"
>>> "\t.long L$set$%d\n"
>>> @@ -4032,15 +4025,14 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long LASFDE%d-EH_frame1\n"
>>> "\t.long %s-.\n"
>>> "\t.long %d\n"
>>> - "\t.byte 0\n" /* augmentation length */
>>> - "\t.byte 0xe\n\t.byte %d\n\t.byte 1\n" /* def_cfa_offset */
>>> - "\t.byte 0x9e\n\t.byte 1\n" /* offset lr */
>>> - "\t.byte 0x9d\n\t.byte 2\n", /* offset fp */
>>> - name, j, j, j, j, j, j, j, name, size, CFRAME_SIZE);
>>> + "\t.uleb128 0\n" /* augmentation length */
>>> + "\t.byte 0x9e\n\t.uleb128 1\n" /* offset lr */
>>> + "\t.byte 0x9d\n\t.uleb128 2\n", /* offset fp */
>>> + j, j, j, j, j, j, j, name, size);
>>> for (i = 19; i <= 28; i++) /* offset x19-x28 */
>>> - fprintf(ctx->fp, "\t.byte 0x%x\n\t.byte %d\n", 0x80+i, i+(3-19));
>>> + fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>>> for (i = 8; i <= 15; i++) /* offset d8-d15 */
>>> - fprintf(ctx->fp, "\t.byte 5\n\t.byte 0x%x\n\t.byte %d\n",
>>> + fprintf(ctx->fp, "\t.byte 5\n\t.uleb128 0x%x\n\t.uleb128 %d\n",
>>> 64+i, i+(3+(28-19+1)-8));
>>> fprintf(ctx->fp,
>>> "\t.align 3\n"
>>> @@ -4056,16 +4048,15 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long 0\n"
>>> "\t.byte 0x1\n"
>>> "\t.ascii \"zR\\0\"\n"
>>> - "\t.byte 0x1\n"
>>> - "\t.byte 128-8\n"
>>> + "\t.uleb128 0x1\n"
>>> + "\t.sleb128 -8\n"
>>> "\t.byte 30\n" /* Return address is in lr. */
>>> - "\t.byte 1\n" /* augmentation length */
>>> + "\t.uleb128 1\n" /* augmentation length */
>>> "\t.byte 0x1b\n" /* pcrel|sdata4 */
>>> - "\t.byte 0xc\n\t.byte 31\n\t.byte 0\n" /* def_cfa sp */
>>> + "\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n" /* def_cfa fp 16 */
>>> "\t.align 3\n"
>>> "LECIEY:\n\n");
>>> fprintf(ctx->fp,
>>> - "_lj_vm_ffi_call.eh:\n"
>>> "LSFDEY:\n"
>>> "\t.set L$set$yy,LEFDEY-LASFDEY\n"
>>> "\t.long L$set$yy\n"
>>> @@ -4073,13 +4064,11 @@ static void emit_asm_debug(BuildCtx *ctx)
>>> "\t.long LASFDEY-EH_frame2\n"
>>> "\t.long _lj_vm_ffi_call-.\n"
>>> "\t.long %d\n"
>>> - "\t.byte 0\n" /* augmentation length */
>>> - "\t.byte 0xe\n\t.byte 32\n" /* def_cfa_offset */
>>> - "\t.byte 0x9e\n\t.byte 1\n" /* offset lr */
>>> - "\t.byte 0x9d\n\t.byte 2\n" /* offset fp */
>>> - "\t.byte 0x93\n\t.byte 3\n" /* offset x19 */
>>> - "\t.byte 0x94\n\t.byte 4\n" /* offset x20 */
>>> - "\t.byte 0xd\n\t.uleb128 0x1d\n" /* def_cfa_register fp */
>>> + "\t.uleb128 0\n" /* augmentation length */
>>> + "\t.byte 0x9e\n\t.uleb128 1\n" /* offset lr */
>>> + "\t.byte 0x9d\n\t.uleb128 2\n" /* offset fp */
>>> + "\t.byte 0x93\n\t.uleb128 3\n" /* offset x19 */
>>> + "\t.byte 0x94\n\t.uleb128 4\n" /* offset x20 */
>>> "\t.align 3\n"
>>> "LEFDEY:\n\n", fcsize);
>>> }
>>> diff --git a/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua b/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
>>> new file mode 100644
>>> index 00000000..cdeea441
>>> --- /dev/null
>>> +++ b/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
>>
>><snipped>
>>
>>> --
>>> 2.37.0 (Apple Git-136)
>>>
>>
>>--
>>Best regards,
>>Sergey Kaplun
>[1]:  https://faultlore.com/blah/compact-unwinding/#unwinding-tables-dwarf-cfi
>[2]:  https://opensource.apple.com/source/libunwind/libunwind-35.3/include/mach-o/compact_unwind_encoding.h
>--
>Best regards,
>Maxim Kokryashkin
> 

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Re: [Tarantool-patches] [PATCH luajit v4 8/8] OSX/ARM64: Fix external unwinding.

[Sergey Kaplun via Tarantool-patches]

Hi, thanks for the explanations!
LGTM, then.

On 30.11.22, Maxim Kokryashkin wrote:
> 
> Hi!
> Thanks for the review!
>  
> > 
> >>Hi, Maksim!
> >>
> >>Thanks for the patch!
> >>
> >>LGTM, but I have a bunch of questions to clarify it.
> >>
> >>On 28.10.22, Maksim Kokryashkin wrote:
> >>> Contributed by Edmund Kapusniak. For more info,
> >>> see #698 and #757.
> >>>
> >>> (cherry picked from commit c38747b626b978555324504ec29a110f6b04902f)
> >>>
> >>> To allow compiler generate compact unwind info generation
> >>> for Mach-O, fp must point to the saved fp, and the frame
> >>> must be specified relative to fp+16.
> >>
> >>Is there any link to documentation or source code to inspect this
> >>behaviour?
> >Unfortunately, there are no official docs for that. However, there is
> >a community effort to create one here[1]. Also, this header file from
> >the Apple’s sources is quite useful. Added both of them to commit
> >message for those who will get the masculine urge to dive into this.

Meh, not much info about it in the mentioned doc.

I suppose that aarch64 ABI requires to save fp and lr by analog with arm
arch. See the following comment for arm (unfortunately, there is no such
comment for aarch64).
https://github.com/gcc-mirror/gcc/blob/master/gcc/config/arm/arm.h#L812

But I'm still struggling to find some relative docs about it.

> >>
> >>> ELF unwind info has
> >>> been updated to also use fp+16 rather than sp+CFRAME_SIZE.
> >>

<snipped>

> >>> Offset to pointer to personality routine specified as @GOT-. rather
> >>> than @GOTPCREL.
> >>
> >>Does it mean that we use incorrect encoded offset (I see encoding for
> >>offset is still the same) for our personality routine?
> >>If so, maybe the other changes are just refactoring?
> >No, that is not correct. Offset has changed, because any 
> >`func@GOT` expression is translated into offset.
> >Moreover, I doubt it is possible to fill in offset to GOT by hand.
> >What goes after the pointer to the personality routine
> >is LSDA, according to the Apple’s source[2]. @GOTPCREL and @GOT
> >are interchangeable most of the time, except for the cases when signed
> >32-bit RIP references are not enough for you, which seems to be the case here.

So, GOTPCREL allows you to "recalculate" reference to a function to
32-bit value and use it? Do I get the idea correct?

> >>
> >>>
> >>> Re-enabled LUAJIT_UNWIND_EXTERNAL by default on OSX.
> >>>
> >>> Maxim Kokryashkin:
> >>> * added the description for the issue and the test
> >>>
> >>> Resolves tarantool/tarantool#6096
> >>> Part of tarantool/tarantool#7230
> >>> ---

<snipped>

> >[1]:  https://faultlore.com/blah/compact-unwinding/#unwinding-tables-dwarf-cfi
> >[2]:  https://opensource.apple.com/source/libunwind/libunwind-35.3/include/mach-o/compact_unwind_encoding.h
> >--
> >Best regards,
> >Maxim Kokryashkin
> > 

-- 
Best regards,
Sergey Kaplun

Re: [Tarantool-patches] [PATCH luajit v4 8/8] OSX/ARM64: Fix external unwinding.

[Sergey Kaplun via Tarantool-patches]

Hi, again!

On 01.12.22, Sergey Kaplun via Tarantool-patches wrote:
> Hi, thanks for the explanations!
> LGTM, then.
> 
> On 30.11.22, Maxim Kokryashkin wrote:
> > 
> > Hi!
> > Thanks for the review!
> >  
> > > 
> > >>Hi, Maksim!
> > >>
> > >>Thanks for the patch!
> > >>
> > >>LGTM, but I have a bunch of questions to clarify it.
> > >>
> > >>On 28.10.22, Maksim Kokryashkin wrote:
> > >>> Contributed by Edmund Kapusniak. For more info,
> > >>> see #698 and #757.
> > >>>
> > >>> (cherry picked from commit c38747b626b978555324504ec29a110f6b04902f)
> > >>>
> > >>> To allow compiler generate compact unwind info generation
> > >>> for Mach-O, fp must point to the saved fp, and the frame
> > >>> must be specified relative to fp+16.
> > >>
> > >>Is there any link to documentation or source code to inspect this
> > >>behaviour?
> > >Unfortunately, there are no official docs for that. However, there is
> > >a community effort to create one here[1]. Also, this header file from
> > >the Apple’s sources is quite useful. Added both of them to commit
> > >message for those who will get the masculine urge to dive into this.
> 
> Meh, not much info about it in the mentioned doc.
> 
> I suppose that aarch64 ABI requires to save fp and lr by analog with arm
> arch. See the following comment for arm (unfortunately, there is no such
> comment for aarch64).
> https://github.com/gcc-mirror/gcc/blob/master/gcc/config/arm/arm.h#L812
> 
> But I'm still struggling to find some relative docs about it.
> 
> > >>
> > >>> ELF unwind info has
> > >>> been updated to also use fp+16 rather than sp+CFRAME_SIZE.
> > >>
> 
> <snipped>
> 
> > >>> Offset to pointer to personality routine specified as @GOT-. rather
> > >>> than @GOTPCREL.
> > >>
> > >>Does it mean that we use incorrect encoded offset (I see encoding for
> > >>offset is still the same) for our personality routine?
> > >>If so, maybe the other changes are just refactoring?
> > >No, that is not correct. Offset has changed, because any 
> > >`func@GOT` expression is translated into offset.
> > >Moreover, I doubt it is possible to fill in offset to GOT by hand.
> > >What goes after the pointer to the personality routine
> > >is LSDA, according to the Apple’s source[2]. @GOTPCREL and @GOT
> > >are interchangeable most of the time, except for the cases when signed
> > >32-bit RIP references are not enough for you, which seems to be the case here.
> 
> So, GOTPCREL allows you to "recalculate" reference to a function to
> 32-bit value and use it? Do I get the idea correct?

Yes, this is the issue mentioned here:
https://github.com/LuaJIT/LuaJIT/issues/698#issuecomment-841645665

And usage of @GOT-. fixes the build for M1.

> 
> > >>
> > >>>
> > >>> Re-enabled LUAJIT_UNWIND_EXTERNAL by default on OSX.
> > >>>
> > >>> Maxim Kokryashkin:
> > >>> * added the description for the issue and the test
> > >>>
> > >>> Resolves tarantool/tarantool#6096
> > >>> Part of tarantool/tarantool#7230
> > >>> ---
> 
> <snipped>
> 
> > >[1]:  https://faultlore.com/blah/compact-unwinding/#unwinding-tables-dwarf-cfi
> > >[2]:  https://opensource.apple.com/source/libunwind/libunwind-35.3/include/mach-o/compact_unwind_encoding.h
> > >--
> > >Best regards,
> > >Maxim Kokryashkin
> > > 
> 
> -- 
> Best regards,
> Sergey Kaplun

-- 
Best regards,
Sergey Kaplun

Re: [Tarantool-patches] [PATCH luajit v4 8/8] OSX/ARM64: Fix external unwinding.

[sergos via Tarantool-patches]

Hi!

Thanks for the patch!

LGTM.

Sergos

> On 28 Oct 2022, at 12:26, Maksim Kokryashkin <max.kokryashkin@gmail.com> wrote:
> 
> Contributed by Edmund Kapusniak. For more info,
> see #698 and #757.
> 
> (cherry picked from commit c38747b626b978555324504ec29a110f6b04902f)
> 
> To allow compiler generate compact unwind info generation
> for Mach-O, fp must point to the saved fp, and the frame
> must be specified relative to fp+16. ELF unwind info has
> been updated to also use fp+16 rather than sp+CFRAME_SIZE.
> 
> Offset to pointer to personality routine specified as @GOT-. rather
> than @GOTPCREL.
> 
> Re-enabled LUAJIT_UNWIND_EXTERNAL by default on OSX.
> 
> Maxim Kokryashkin:
> * added the description for the issue and the test
> 
> Resolves tarantool/tarantool#6096
> Part of tarantool/tarantool#7230
> ---
> cmake/SetTargetFlags.cmake                    |  4 +-
> src/Makefile.original                         |  5 +-
> src/vm_arm64.dasc                             | 89 ++++++++-----------
> ...-6096-external-unwinding-on-arm64.test.lua | 13 +++
> 4 files changed, 54 insertions(+), 57 deletions(-)
> create mode 100644 test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
> 
> diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
> index 8abb6288..7cf26be1 100644
> --- a/cmake/SetTargetFlags.cmake
> +++ b/cmake/SetTargetFlags.cmake
> @@ -16,9 +16,7 @@ LuaJITTestArch(TESTARCH "${TARGET_C_FLAGS}")
> LuaJITArch(LUAJIT_ARCH "${TESTARCH}")
> 
> if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
> -  if(NOT LUAJIT_ARCH STREQUAL "arm64")
> -    AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> -  endif()
> +  AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
> else()
>   string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
>   if(UNWIND_POS EQUAL -1)
> diff --git a/src/Makefile.original b/src/Makefile.original
> index 2d014e43..813d9c12 100644
> --- a/src/Makefile.original
> +++ b/src/Makefile.original
> @@ -325,10 +325,7 @@ ifeq (Darwin,$(TARGET_SYS))
>     export MACOSX_DEPLOYMENT_TARGET=10.4
>   endif
>   TARGET_STRIP+= -x
> -  # Ext. unwinding is broken on OSX/ARM64 until someone finds a fix. See #698.
> -  ifneq (arm64,$(TARGET_LJARCH))
> -    TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
> -  endif
> +  TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
>   TARGET_XSHLDFLAGS= -dynamiclib -single_module -undefined dynamic_lookup -fPIC
>   TARGET_DYNXLDOPTS=
>   TARGET_XSHLDFLAGS+= -install_name $(TARGET_DYLIBPATH) -compatibility_version $(MAJVER).$(MINVER) -current_version $(MAJVER).$(MINVER).$(RELVER)
> diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
> index ccfa72bd..f517a808 100644
> --- a/src/vm_arm64.dasc
> +++ b/src/vm_arm64.dasc
> @@ -81,8 +81,7 @@
> |
> |.define CFRAME_SPACE,	208
> |//----- 16 byte aligned, <-- sp entering interpreter
> -|.define SAVE_LR,	[sp, #200]
> -|.define SAVE_FP,	[sp, #192]
> +|.define SAVE_FP_LR_,	192
> |.define SAVE_GPR_,	112		// 112+10*8: 64 bit GPR saves
> |.define SAVE_FPR_,	48		// 48+8*8: 64 bit FPR saves
> |// Unused		[sp, #44]	// 32 bit values
> @@ -108,8 +107,8 @@
> |
> |.macro saveregs
> |  sub sp, sp, # CFRAME_SPACE
> -|  stp fp, lr, SAVE_FP
> -|  add fp, sp, #0
> +|  stp fp, lr, [sp, # SAVE_FP_LR_]
> +|  add fp, sp, # SAVE_FP_LR_
> |  stp x20, x19, [sp, # SAVE_GPR_+(27-19)*8]
> |  save_ 21, 22, 8, 9
> |  save_ 23, 24, 10, 11
> @@ -122,7 +121,7 @@
> |  rest_ 23, 24, 10, 11
> |  rest_ 25, 26, 12, 13
> |  rest_ 27, 28, 14, 15
> -|  ldp fp, lr, SAVE_FP
> +|  ldp fp, lr, [sp, # SAVE_FP_LR_]
> |  add sp, sp, # CFRAME_SPACE
> |.endmacro
> |
> @@ -504,8 +503,9 @@ static void build_subroutines(BuildCtx *ctx)
>   |    ldr GL, L->glref			// Setup pointer to global state.
>   |     mov BASE, CARG2
>   |   str CARG1, SAVE_PC		// Any value outside of bytecode is ok.
> -  |  str RC, SAVE_CFRAME
> -  |  str fp, L->cframe			// Add our C frame to cframe chain.
> +  |  add TMP0, sp, #0
> +  |   str RC, SAVE_CFRAME
> +  |  str TMP0, L->cframe		// Add our C frame to cframe chain.
>   |
>   |3:  // Entry point for vm_cpcall/vm_resume (BASE = base, PC = ftype).
>   |  str L, GL->cur_L
> @@ -540,8 +540,9 @@ static void build_subroutines(BuildCtx *ctx)
>   |   sub RA, RA, RB			// Compute -savestack(L, L->top).
>   |   str RAw, SAVE_NRES		// Neg. delta means cframe w/o frame.
>   |  str wzr, SAVE_ERRF			// No error function.
> -  |  str RC, SAVE_CFRAME
> -  |  str fp, L->cframe			// Add our C frame to cframe chain.
> +  |  add TMP0, sp, #0
> +  |   str RC, SAVE_CFRAME
> +  |  str TMP0, L->cframe		// Add our C frame to cframe chain.
>   |    str L, GL->cur_L
>   |  blr CARG4			// (lua_State *L, lua_CFunction func, void *ud)
>   |  mov BASE, CRET1
> @@ -2129,14 +2130,14 @@ static void build_subroutines(BuildCtx *ctx)
>   |  .type CCSTATE, CCallState, x19
>   |  stp x20, CCSTATE, [sp, #-32]!
>   |  stp fp, lr, [sp, #16]
> -  |  add fp, sp, #0
> +  |  add fp, sp, #16
>   |  mov CCSTATE, x0
>   |  ldr TMP0w, CCSTATE:x0->spadj
>   |   ldrb TMP1w, CCSTATE->nsp
>   |    add TMP2, CCSTATE, #offsetof(CCallState, stack)
>   |   subs TMP1, TMP1, #1
>   |    ldr TMP3, CCSTATE->func
> -  |  sub sp, fp, TMP0
> +  |  sub sp, sp, TMP0
>   |   bmi >2
>   |1:  // Copy stack slots
>   |  ldr TMP0, [TMP2, TMP1, lsl #3]
> @@ -2154,7 +2155,7 @@ static void build_subroutines(BuildCtx *ctx)
>   |   ldp d6, d7, CCSTATE->fpr[6]
>   |  ldr x8, CCSTATE->retp
>   |  blr TMP3
> -  |  mov sp, fp
> +  |  sub sp, fp, #16
>   |  stp x0, x1, CCSTATE->gpr[0]
>   |   stp d0, d1, CCSTATE->fpr[0]
>   |   stp d2, d3, CCSTATE->fpr[2]
> @@ -3879,7 +3880,7 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.uleb128 0x1\n"
> 	"\t.sleb128 -8\n"
> 	"\t.byte 30\n"				/* Return address is in lr. */
> -	"\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
> 	"\t.align 3\n"
> 	".LECIE0:\n\n");
>     fprintf(ctx->fp,
> @@ -3889,10 +3890,9 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long .Lframe0\n"
> 	"\t.quad .Lbegin\n"
> 	"\t.quad %d\n"
> -	"\t.byte 0xe\n\t.uleb128 %d\n"		/* def_cfa_offset */
> 	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> 	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> -	fcofs, CFRAME_SIZE);
> +	fcofs);
>     for (i = 19; i <= 28; i++)  /* offset x19-x28 */
>       fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>     for (i = 8; i <= 15; i++)  /* offset d8-d15 */
> @@ -3909,12 +3909,10 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long .Lframe0\n"
> 	"\t.quad lj_vm_ffi_call\n"
> 	"\t.quad %d\n"
> -	"\t.byte 0xe\n\t.uleb128 32\n"		/* def_cfa_offset */
> 	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> 	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
> 	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
> 	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
> -	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
> 	"\t.align 3\n"
> 	".LEFDE1:\n\n", (int)ctx->codesz - fcofs);
> #endif
> @@ -3933,7 +3931,7 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> 	"\t.long lj_err_unwind_dwarf-.\n"
> 	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
> 	"\t.align 3\n"
> 	".LECIE1:\n\n");
>     fprintf(ctx->fp,
> @@ -3944,10 +3942,9 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long .Lbegin-.\n"
> 	"\t.long %d\n"
> 	"\t.uleb128 0\n"			/* augmentation length */
> -	"\t.byte 0xe\n\t.uleb128 %d\n"		/* def_cfa_offset */
> 	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> 	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> -	fcofs, CFRAME_SIZE);
> +	fcofs);
>     for (i = 19; i <= 28; i++)  /* offset x19-x28 */
>       fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>     for (i = 8; i <= 15; i++)  /* offset d8-d15 */
> @@ -3969,7 +3966,7 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.byte 30\n"				/* Return address is in lr. */
> 	"\t.uleb128 1\n"			/* augmentation length */
> 	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.uleb128 31\n\t.uleb128 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
> 	"\t.align 3\n"
> 	".LECIE2:\n\n");
>     fprintf(ctx->fp,
> @@ -3980,18 +3977,15 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long lj_vm_ffi_call-.\n"
> 	"\t.long %d\n"
> 	"\t.uleb128 0\n"			/* augmentation length */
> -	"\t.byte 0xe\n\t.uleb128 32\n"		/* def_cfa_offset */
> 	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> 	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
> 	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
> 	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
> -	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
> 	"\t.align 3\n"
> 	".LEFDE3:\n\n", (int)ctx->codesz - fcofs);
> #endif
>     break;
> -    /* Disabled until someone finds a fix. See #698. */
> -#if !LJ_NO_UNWIND && 0
> +#if !LJ_NO_UNWIND
>   case BUILD_machasm: {
> #if LJ_HASFFI
>     int fcsize = 0;
> @@ -4006,14 +4000,14 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long 0\n"
> 	"\t.byte 0x1\n"
> 	"\t.ascii \"zPR\\0\"\n"
> -	"\t.byte 0x1\n"
> -	"\t.byte 128-8\n"
> +	"\t.uleb128 0x1\n"
> +	"\t.sleb128 -8\n"
> 	"\t.byte 30\n"				/* Return address is in lr. */
> -	"\t.byte 6\n"				/* augmentation length */
> +	"\t.uleb128 6\n"			/* augmentation length */
> 	"\t.byte 0x9b\n"			/* indirect|pcrel|sdata4 */
> -	"\t.long _lj_err_unwind_dwarf@GOTPCREL\n"
> +	"\t.long _lj_err_unwind_dwarf@GOT-.\n"
> 	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.byte 31\n\t.byte 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
> 	"\t.align 3\n"
> 	"LECIEX:\n\n");
>     for (j = 0; j < ctx->nsym; j++) {
> @@ -4024,7 +4018,6 @@ static void emit_asm_debug(BuildCtx *ctx)
>       if (!strcmp(name, "_lj_vm_ffi_call")) { fcsize = size; continue; }
> #endif
>       fprintf(ctx->fp,
> -	"%s.eh:\n"
> 	"LSFDE%d:\n"
> 	"\t.set L$set$%d,LEFDE%d-LASFDE%d\n"
> 	"\t.long L$set$%d\n"
> @@ -4032,15 +4025,14 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long LASFDE%d-EH_frame1\n"
> 	"\t.long %s-.\n"
> 	"\t.long %d\n"
> -	"\t.byte 0\n"				/* augmentation length */
> -	"\t.byte 0xe\n\t.byte %d\n\t.byte 1\n"	/* def_cfa_offset */
> -	"\t.byte 0x9e\n\t.byte 1\n"		/* offset lr */
> -	"\t.byte 0x9d\n\t.byte 2\n",		/* offset fp */
> -	name, j, j, j, j, j, j, j, name, size, CFRAME_SIZE);
> +	"\t.uleb128 0\n"			/* augmentation length */
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n",		/* offset fp */
> +	j, j, j, j, j, j, j, name, size);
>       for (i = 19; i <= 28; i++)  /* offset x19-x28 */
> -	fprintf(ctx->fp, "\t.byte 0x%x\n\t.byte %d\n", 0x80+i, i+(3-19));
> +	fprintf(ctx->fp, "\t.byte 0x%x\n\t.uleb128 %d\n", 0x80+i, i+(3-19));
>       for (i = 8; i <= 15; i++)  /* offset d8-d15 */
> -	fprintf(ctx->fp, "\t.byte 5\n\t.byte 0x%x\n\t.byte %d\n",
> +	fprintf(ctx->fp, "\t.byte 5\n\t.uleb128 0x%x\n\t.uleb128 %d\n",
> 		64+i, i+(3+(28-19+1)-8));
>       fprintf(ctx->fp,
> 	"\t.align 3\n"
> @@ -4056,16 +4048,15 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long 0\n"
> 	"\t.byte 0x1\n"
> 	"\t.ascii \"zR\\0\"\n"
> -	"\t.byte 0x1\n"
> -	"\t.byte 128-8\n"
> +	"\t.uleb128 0x1\n"
> +	"\t.sleb128 -8\n"
> 	"\t.byte 30\n"				/* Return address is in lr. */
> -	"\t.byte 1\n"				/* augmentation length */
> +	"\t.uleb128 1\n"			/* augmentation length */
> 	"\t.byte 0x1b\n"			/* pcrel|sdata4 */
> -	"\t.byte 0xc\n\t.byte 31\n\t.byte 0\n"	/* def_cfa sp */
> +	"\t.byte 0xc\n\t.uleb128 29\n\t.uleb128 16\n"	/* def_cfa fp 16 */
> 	"\t.align 3\n"
> 	"LECIEY:\n\n");
>       fprintf(ctx->fp,
> -	"_lj_vm_ffi_call.eh:\n"
> 	"LSFDEY:\n"
> 	"\t.set L$set$yy,LEFDEY-LASFDEY\n"
> 	"\t.long L$set$yy\n"
> @@ -4073,13 +4064,11 @@ static void emit_asm_debug(BuildCtx *ctx)
> 	"\t.long LASFDEY-EH_frame2\n"
> 	"\t.long _lj_vm_ffi_call-.\n"
> 	"\t.long %d\n"
> -	"\t.byte 0\n"				/* augmentation length */
> -	"\t.byte 0xe\n\t.byte 32\n"		/* def_cfa_offset */
> -	"\t.byte 0x9e\n\t.byte 1\n"		/* offset lr */
> -	"\t.byte 0x9d\n\t.byte 2\n"		/* offset fp */
> -	"\t.byte 0x93\n\t.byte 3\n"		/* offset x19 */
> -	"\t.byte 0x94\n\t.byte 4\n"		/* offset x20 */
> -	"\t.byte 0xd\n\t.uleb128 0x1d\n"	/* def_cfa_register fp */
> +	"\t.uleb128 0\n"			/* augmentation length */
> +	"\t.byte 0x9e\n\t.uleb128 1\n"		/* offset lr */
> +	"\t.byte 0x9d\n\t.uleb128 2\n"		/* offset fp */
> +	"\t.byte 0x93\n\t.uleb128 3\n"		/* offset x19 */
> +	"\t.byte 0x94\n\t.uleb128 4\n"		/* offset x20 */
> 	"\t.align 3\n"
> 	"LEFDEY:\n\n", fcsize);
>     }
> diff --git a/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua b/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
> new file mode 100644
> index 00000000..cdeea441
> --- /dev/null
> +++ b/test/tarantool-tests/gh-6096-external-unwinding-on-arm64.test.lua
> @@ -0,0 +1,13 @@
> +local tap = require('tap')
> +
> +-- Test file to check correctnes of external unwinding
> +-- in LuaJIT.
> +-- See also https://github.com/LuaJIT/LuaJIT/issues/698,
> +-- https://github.com/LuaJIT/LuaJIT/pull/757.
> +local test = tap.test('gh-6096-external-unwinding-on-arm64')
> +test:plan(1)
> +
> +local res = pcall(require, 'not-existing-module')
> +test:ok(res == false, 'successful unwinding in pcall')
> +
> +os.exit(test:check() and 0 or 1)
> -- 
> 2.37.0 (Apple Git-136)
>