fsfw/fsfw
fsfw
/
fsfw
10
3
Fork 6
Code Issues 31 Pull Requests 4 Releases 10 Wiki Activity

Add LTO support #616

Merged
gaisser merged 15 commits from mueller/add-lto-support into development 2022-05-12 16:56:55 +02:00
Conversation 0 Commits 15 Files Changed 2 +37 -6
muellerr commented 2022-05-09 10:29:51 +02:00
Owner
Copy Link

  • LTO support: Allow using LTO/IPO by setting FSFW_ENABLE_LTO=1. CMake is able to detect whether
    the user compiler supports IPO/LPO. LTO is on by default now. Most modern compilers support it, can make good use of it and it usually makes the code faster and/or smaller.

  • This is preparation for a possible {fmt} support. fmt usually makes the binary
    larger if it was not installed as a shared library, so this option can reduce code size.

UPDATE:

  • Enabling LTO will actually cause the compiler to only produce thin LTO by adding -flto -fno-fat-lto-objects to the compiler options. I am not sure this is an ideal choice because if an application linking against the FSFW does not use LTO, there can be compile issues (e.g. observed when compiling the FSFW tests without LTO). This is a known issue as can be seen in the multiple CMake issues for it: https://gitlab.kitware.com/cmake/cmake/-/issues/22913, https://gitlab.kitware.com/cmake/cmake/-/issues/16808, https://gitlab.kitware.com/cmake/cmake/-/issues/21696

  • I would suggest still keeping this option but letting the default be OFF for now. For me, it makes the most sense to specifically compile the FSFW with fat LTO where the static library contains the regular object code and the intermedia representation which can be used by application compiling with and without LTO. CMake might have this option soon in the future. If a user wants to use full LTO, they can simly set the following option in the application CMakeLists.txt

    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)

    This will cause the compiler to compile both the application and the framework with
    thin LTO, which is okay in that case.

- LTO support: Allow using LTO/IPO by setting `FSFW_ENABLE_LTO=1`. CMake is able to detect whether the user compiler supports IPO/LPO. LTO is on by default now. Most modern compilers support it, can make good use of it and it usually makes the code faster and/or smaller. - This is preparation for a possible `{fmt}` support. fmt usually makes the binary larger if it was not installed as a shared library, so this option can reduce code size. UPDATE: - Enabling LTO will actually cause the compiler to only produce thin LTO by adding ` -flto -fno-fat-lto-objects` to the compiler options. I am not sure this is an ideal choice because if an application linking against the FSFW does not use LTO, there can be compile issues (e.g. observed when compiling the FSFW tests without LTO). This is a known issue as can be seen in the multiple CMake issues for it: https://gitlab.kitware.com/cmake/cmake/-/issues/22913, https://gitlab.kitware.com/cmake/cmake/-/issues/16808, https://gitlab.kitware.com/cmake/cmake/-/issues/21696 - I would suggest still keeping this option but letting the default be OFF for now. For me, it makes the most sense to specifically compile the FSFW with fat LTO where the static library contains the regular object code and the intermedia representation which can be used by application compiling with and without LTO. CMake might have this option soon in the future. If a user wants to use full LTO, they can simly set the following option in the application `CMakeLists.txt` ```cmake set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE) ``` This will cause the compiler to compile both the application and the framework with thin LTO, which is okay in that case.
muellerr added 2 commits 2022-05-09 10:29:53 +02:00
fsfw/fsfw/pipeline/head Build started... Details
fsfw/fsfw/pipeline/pr-development This commit looks good Details
a943e4eebb
enable LTO where applicable
muellerr added 1 commit 2022-05-09 10:31:12 +02:00
fsfw/fsfw/pipeline/pr-development This commit looks good Details
a4bd5a2aaa
update changelog
muellerr added this to the v5.0.0 milestone 2022-05-09 10:31:18 +02:00
muellerr changed title from mueller/add-lto-support to Add LTO support 2022-05-09 10:31:23 +02:00
mohr was assigned by muellerr 2022-05-09 10:31:38 +02:00
mohr was unassigned by muellerr 2022-05-09 10:31:46 +02:00
meierj was assigned by muellerr 2022-05-09 10:31:46 +02:00
meierj was unassigned by muellerr 2022-05-09 10:31:51 +02:00
muellerr requested review from gaisser 2022-05-09 10:31:56 +02:00
muellerr force-pushed mueller/add-lto-support from 8334af77ea to 637512ad77 2022-05-09 10:34:35 +02:00 Compare
muellerr added the
feature
build
 labels 2022-05-09 10:40:07 +02:00
muellerr added 1 commit 2022-05-09 15:17:21 +02:00
fsfw/fsfw/pipeline/pr-development There was a failure building this commit Details
8a40878eb5 Merge remote-tracking branch 'origin/development' into mueller/add-lto-support
muellerr added 1 commit 2022-05-09 15:52:33 +02:00
fsfw/fsfw/pipeline/pr-development There was a failure building this commit Details
75132c1e39 Merge branch 'development' into mueller/add-lto-support
muellerr added 2 commits 2022-05-09 16:07:17 +02:00
muellerr added 1 commit 2022-05-09 16:09:42 +02:00
fsfw/fsfw/pipeline/pr-development This commit looks good Details
dd9e28fca1 Merge branch 'development' into mueller/add-lto-support
muellerr added 1 commit 2022-05-09 22:34:32 +02:00
fsfw/fsfw/pipeline/pr-development This commit looks good Details
eb0223bc51 Merge branch 'development' into mueller/add-lto-support
muellerr added 1 commit 2022-05-10 11:19:41 +02:00
fsfw/fsfw/pipeline/pr-development This commit looks good Details
0fe1b70bae
keep LTO option off by default
gaisser added 1 commit 2022-05-10 11:51:43 +02:00
fsfw/fsfw/pipeline/pr-development This commit looks good Details
0410ecd9e3 Merge branch 'development' into mueller/add-lto-support
gaisser reviewed 2022-05-10 11:53:39 +02:00
CMakeLists.txt Outdated
@ -36,0 +36,4 @@
include(CheckIPOSupported)
check_ipo_supported(RESULT IPO_SUPPORTED OUTPUT IPO_ERROR)
if(NOT IPO_SUPPORTED)
message(STATUS "FSFW | IPO/LTO not supported: ${IPO_ERROR}")
gaisser commented 2022-05-10 11:53:39 +02:00
Owner
Copy Link

Do we need that check if FSFW_ENABLE_IPO is off?

Do we need that check if FSFW_ENABLE_IPO is off?
muellerr commented 2022-05-10 13:07:42 +02:00
Author
Owner
Copy Link

fixed it

fixed it
gaisser marked this conversation as resolved
muellerr added 2 commits 2022-05-10 11:57:06 +02:00
muellerr added 1 commit 2022-05-10 13:08:25 +02:00
fsfw/fsfw/pipeline/pr-development This commit looks good Details
e05c72b062
minor formatting fix
gaisser approved these changes 2022-05-12 16:56:49 +02:00
gaisser left a comment
Owner
Copy Link

LGTM

LGTM
gaisser merged commit b99160e850 into development 2022-05-12 16:56:55 +02:00
gaisser deleted branch mueller/add-lto-support 2022-05-12 16:57:01 +02:00
Sign in to join this conversation.
Reviewers
No reviewers
gaisser
Labels
Clear labels   
API Change

Changes the API, so Users need to adapted

  
Breaking API Change

Changes the API in a non backwards compatible way

  
bug

Something is not working

  
build

Issues related to the buildsystem, including CI

  
cosmetics

Small change most users won't notice

  
Documentation

Improvement of code documentation

  
duplicate

This issue or pull request already exists

  
feature

New feature

  
help wanted

Need some help

  
hotfix

Quick or important fix that is merged directly into master, causing a new revision

  
invalid

#worksforme

  
question

More information is needed

  
Refactor

Contains a refactoring of some code

  
Tests

Issues related to testing code

  
wontfix

This won't be fixed

No Label
API Change
Breaking API Change
bug
build
cosmetics
Documentation
duplicate
feature
help wanted
hotfix
invalid
question
Refactor
Tests
wontfix
Milestone
Clear milestone
No items
No Milestone
v5.0.0
Assignees
Clear assignees
No Assignees
2 Participants
Notifications
Due Date
The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'.

No due date set.

Dependencies

No dependencies set.

Reference: fsfw/fsfw#616
No description provided.
Delete Branch "mueller/add-lto-support"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?