cmake: c++ exceptions linking support #35647

tejlmand · 2021-05-25T21:12:05Z

Fixes part of: #32448

This commit updates the CMake CMAKE_CXX_LINK_EXECUTABLE to include
crtbegin.o and crtend.o at the right locations when linking with gcc.

It also updates linker scripts to ensure proper location of the
exception header frame sections.

Signed-off-by: Kumar Gala kumar.gala@linaro.org
Signed-off-by: Torsten Rasmussen Torsten.Rasmussen@nordicsemi.no

Update:
The following platforms are fixed with this PR:
qemu_x86
qemu_riscv32
qemu_xtensa

The following platforms still fails:
qemu_x86_64 (fails with exit)
qemu_cortex_a53 (fails with exit)
qemu_riscv64 (fails with exit)
qemu_nios2 (hangs)
qemu_leon3 (fails with trap_instruction)

tejlmand · 2021-05-25T21:13:16Z

@galak I included your linker script modifications from this: #34357

dcpleung · 2021-05-25T21:52:43Z

Could you refactor the linker script addition into a file, so it can be done via #include?

tejlmand · 2021-05-26T08:08:03Z

Could you refactor the linker script addition into a file, so it can be done via #include?

Done, placed it in cplusplus-ram.ld where we already have linker code related to exception tables.

stephanosio

This claims to fix #32448, but there are some platforms that still fail.

Just noting that #32448 should stay open to keep track of them ... (see #32448 (comment)).

stephanosio

The following should be updated to test the platforms that work after the changes in this PR:

zephyr/tests/subsys/cpp/libcxx/testcase.yaml

Lines 11 to 19 in 7b7ed2b

    
           cpp.libcxx.exceptions: 
        
             # FIXME: change when issue is resolved #32448 
        
             platform_allow: mps2_an385 
        
             toolchain_exclude: xcc 
        
             min_flash: 54 
        
             tags: cpp 
        
             timeout: 5 
        
             extra_configs: 
        
                 - CONFIG_EXCEPTIONS=y

tejlmand · 2021-05-26T15:44:01Z

This claims to fix #32448, but there are some platforms that still fail.

Looking into this, the CPP_TEST provided in #32448 passes on the platforms: qemu_xtensa, qemu_riscv32, qemu_cortex_m3 and qemu_x86 works.
As example:

$ west build -b qemu_xtensa --pristine -t run
-- west build: making build dir /projects/github/ncs/zephyr/tests/CPP_TEST/build pristine
...
*** Booting Zephyr OS build zephyr-v2.5.0-4098-ge2501fd08ef3  ***
Running test suite framework_tests
===================================================================
START - test_assert
 PASS - test_assert in 0.1 seconds
===================================================================
START - test_cexception
 PASS - test_cexception in 0.2 seconds
===================================================================
Test suite framework_tests succeeded
===================================================================
PROJECT EXECUTION SUCCESSFUL

also some archs passes on tests/subsys/cpp/libcxx when built and executed manually, like qemu_xtensa:

$  west build -b qemu_xtensa --pristine -t run -- -DCONFIG_EXCEPTIONS=y
-- west build: making build dir /projects/github/ncs/zephyr/tests/subsys/cpp/libcxx/build pristine
...
*** Booting Zephyr OS build zephyr-v2.5.0-4098-ge2501fd08ef3  ***
version 201703
Running test suite libcxx_tests
===================================================================
START - test_array
 PASS - test_array in 0.1 seconds
===================================================================
START - test_vector
 PASS - test_vector in 0.1 seconds
===================================================================
START - test_make_unique
 PASS - test_make_unique in 0.1 seconds
===================================================================
START - test_exception
 PASS - test_exception in 0.8 seconds
===================================================================
Test suite libcxx_tests succeeded
===================================================================
PROJECT EXECUTION SUCCESSFUL
qemu-system-xtensa: terminating on signal 2

but fails when using twister:

$ ./scripts/twister -v -p qemu_xtensa -N  --inline-logs -s  tests/subsys/cpp/libcxx/cpp.libcxx.exceptions
...
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

INFO    - /projects/github/ncs/zephyr/twister-out/qemu_xtensa/tests/subsys/cpp/libcxx/cpp.libcxx.exceptions/build.log

INFO    - 0 of 1 test configurations passed (0.00%), 1 failed, 0 skipped with 0 warnings in 5.36 seconds
INFO    - In total 4 test cases were executed, 0 skipped on 1 out of total 372 platforms (0.27%)
INFO    - 0 test configurations executed on platforms, 1 test configurations were only built.

other archs (riscv32) fails on tests/subsys/cpp/libcxx but not CPP_TEST.

Marked DNM to allow further investigations.

andyross · 2021-05-26T15:48:27Z

cmake/linker/ld/target.cmake

+  # are linked at specific locations.
+  # The location is so important that we cannot let this be controlled by normal
+  # link libraries, instead we must control the link command specifically as
+  # part of toolchain.


FWIW: trying to do this on the command line is fragile. Really this needs to happen in a linker script. Also I wouldn't be surprised if the rules are platform-dependent.

For GCC this has normally be done via a spec file. @andyross Have you seen anywhere that this is done via linker script?

how will you tell the linker which objects (crtbegin.o and crtend.o) to link in a linker file ?
Not to mention that the position of those objects on the linker invocation is important.

This is why this is to be considered a toolchain (linker) setting.

tejlmand · 2021-05-27T09:42:21Z

Updated description text with list of platform that are fixed with this PR, as it stands.
The following platforms are fixed with this PR:
qemu_x86
qemu_riscv32
qemu_xtensa

The following platforms still fails:
qemu_x86_64 (fails with exit)
qemu_cortex_a53 (fails with exit)
qemu_riscv64 (fails with exit)
qemu_nios2 (hangs)
qemu_leon3 (fails with trap_instruction)

Fixes part of: zephyrproject-rtos#32448 This commit updates the CMake CMAKE_CXX_LINK_EXECUTABLE to include crtbegin.o and crtend.o at the right locations when linking with gcc. It also updates linker scripts to ensure proper location of the exception header frame sections. This ensure proper handling of exceptions for those architectures - x86 - xtensa - riscv32 Signed-off-by: Kumar Gala <kumar.gala@linaro.org> Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Increasing ZTEST_STACKSIZE to 4096. This ensures that the riscv32 platforms can succesfully execute the C++ exception test cases. Also add the following platforms to allow list: - qemu_arc_em - qemu_arc_hs - qemu_cortex_m0 - qemu_cortex_m3 - qemu_cortex_r5 - qemu_riscv32 - qemu_x86 - qemu_xtensa Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

tejlmand · 2021-05-27T09:47:03Z

The following should be updated to test the platforms that work after the changes in this PR:

Done.

tejlmand requested review from nashif, carlescufi and galak May 25, 2021 21:12

tejlmand requested review from dcpleung, ioannisg, jhedberg, kgugala, MaureenHelm and pgielda as code owners May 25, 2021 21:12

github-actions bot added area: API Changes to public APIs area: ARM ARM (32-bit) Architecture area: Build System area: RISCv32/64 area: X86 x86 Architecture (32-bit) labels May 25, 2021

tejlmand force-pushed the issues/32448_cpp_exception_linking branch from 6292658 to a8e5874 Compare May 25, 2021 21:14

tejlmand added the bug The issue is a bug, or the PR is fixing a bug label May 25, 2021

tejlmand added this to the v2.6.0 milestone May 25, 2021

tejlmand requested review from carlescufi and removed request for carlescufi May 25, 2021 21:15

carlescufi requested a review from stephanosio May 26, 2021 07:22

tejlmand force-pushed the issues/32448_cpp_exception_linking branch from a8e5874 to 4b2d0cd Compare May 26, 2021 08:00

tejlmand requested a review from andyross as a code owner May 26, 2021 08:00

tejlmand force-pushed the issues/32448_cpp_exception_linking branch from 4b2d0cd to e2501fd Compare May 26, 2021 08:09

galak approved these changes May 26, 2021

View reviewed changes

carlescufi approved these changes May 26, 2021

View reviewed changes

stephanosio reviewed May 26, 2021

View reviewed changes

stephanosio requested changes May 26, 2021

View reviewed changes

zephyrbot added the area: RISCV RISCV Architecture (32-bit & 64-bit) label May 26, 2021

zephyrbot requested review from aasthagr, ceolin, jenmwms, katsuster and mgielda May 26, 2021 15:08

zephyrbot assigned tejlmand May 26, 2021

tejlmand added the DNM This PR should not be merged (Do Not Merge) label May 26, 2021

andyross reviewed May 26, 2021

View reviewed changes

tejlmand force-pushed the issues/32448_cpp_exception_linking branch from e2501fd to 8d096ec Compare May 27, 2021 09:33

github-actions bot added the area: Tests Issues related to a particular existing or missing test label May 27, 2021

tejlmand added 2 commits May 27, 2021 11:42

tejlmand force-pushed the issues/32448_cpp_exception_linking branch from 8d096ec to 33818f0 Compare May 27, 2021 09:44

tejlmand removed the DNM This PR should not be merged (Do Not Merge) label May 27, 2021

galak requested a review from stephanosio May 27, 2021 12:25

stephanosio approved these changes May 27, 2021

View reviewed changes

galak merged commit 08dfe74 into zephyrproject-rtos:main May 27, 2021

stephanosio mentioned this pull request May 27, 2021

cpp: Restrict C++ exceptions usage to supported archs #35722

Closed

tejlmand mentioned this pull request May 27, 2021

C++ exceptions do not work on multiple platforms #32448

Closed

FRASTM mentioned this pull request Jun 1, 2021

the sample kernel/metairq_dispatch fails on nucleo_g474re #35850

Closed

katsuster removed the area: RISCv32/64 label Jun 10, 2021

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

cmake: c++ exceptions linking support #35647

cmake: c++ exceptions linking support #35647

tejlmand commented May 25, 2021 •

edited

Loading

tejlmand commented May 25, 2021

dcpleung commented May 25, 2021

tejlmand commented May 26, 2021

stephanosio left a comment •

edited

Loading

stephanosio left a comment

tejlmand commented May 26, 2021 •

edited

Loading

andyross May 26, 2021

galak May 26, 2021

tejlmand May 26, 2021

tejlmand commented May 27, 2021

tejlmand commented May 27, 2021

	cpp.libcxx.exceptions:
	# FIXME: change when issue is resolved #32448
	platform_allow: mps2_an385
	toolchain_exclude: xcc
	min_flash: 54
	tags: cpp
	timeout: 5
	extra_configs:
	- CONFIG_EXCEPTIONS=y

cmake: c++ exceptions linking support #35647

cmake: c++ exceptions linking support #35647

Conversation

tejlmand commented May 25, 2021 • edited Loading

tejlmand commented May 25, 2021

dcpleung commented May 25, 2021

tejlmand commented May 26, 2021

stephanosio left a comment • edited Loading

Choose a reason for hiding this comment

stephanosio left a comment

Choose a reason for hiding this comment

tejlmand commented May 26, 2021 • edited Loading

andyross May 26, 2021

Choose a reason for hiding this comment

galak May 26, 2021

Choose a reason for hiding this comment

tejlmand May 26, 2021

Choose a reason for hiding this comment

tejlmand commented May 27, 2021

tejlmand commented May 27, 2021

tejlmand commented May 25, 2021 •

edited

Loading

stephanosio left a comment •

edited

Loading

tejlmand commented May 26, 2021 •

edited

Loading