[libc++] Remove official Clang 18 support. #130142
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Since Clang 20 has been release we no longer support Clang 18 per our policy. Note the Clang 18 workarounds will be removed in a follow-up patch.
llvmbot
added
libc++
|
@llvm/pr-subscribers-github-workflow Author: Mark de Wever (mordante) ChangesSince Clang 20 has been release we no longer support Clang 18 per our policy. Note the Clang 18 workarounds will be removed in a follow-up patch. Full diff: https://github.com/llvm/llvm-project/pull/130142.diff 3 Files Affected:
diff --git a/.github/workflows/libcxx-build-and-test.yaml b/.github/workflows/libcxx-build-and-test.yaml
index 5d4394435890a..74889adfa070f 100644
--- a/.github/workflows/libcxx-build-and-test.yaml
+++ b/.github/workflows/libcxx-build-and-test.yaml
@@ -100,10 +100,6 @@ jobs:
- config: 'generic-cxx26'
cc: 'clang-19'
cxx: 'clang++-19'
- # Release transition
- - config: 'generic-cxx23'
- cc: 'clang-18'
- cxx: 'clang++-18'
steps:
- uses: actions/checkout@v4
- name: ${{ matrix.config }}
diff --git a/libcxx/docs/index.rst b/libcxx/docs/index.rst
index e2c62e9ecac02..a8b0d5ce1ee97 100644
--- a/libcxx/docs/index.rst
+++ b/libcxx/docs/index.rst
@@ -131,7 +131,7 @@ velocity, libc++ drops support for older compilers as newer ones are released.
============ =================== ========================== =====================
Compiler Versions Restrictions Support policy
============ =================== ========================== =====================
-Clang 18, 19, 20, 21-git latest two stable releases per `LLVM's release page <https://releases.llvm.org>`_ and the development version
+Clang 19, 20, 21-git latest two stable releases per `LLVM's release page <https://releases.llvm.org>`_ and the development version
AppleClang 15 latest stable release per `Xcode's release page <https://developer.apple.com/documentation/xcode-release-notes>`_
Open XL 17.1.3 (AIX) latest stable release per `Open XL's documentation page <https://www.ibm.com/docs/en/openxl-c-and-cpp-aix>`_
GCC 14 In C++11 or later only latest stable release per `GCC's release page <https://gcc.gnu.org/releases.html>`_
diff --git a/libcxx/include/__configuration/compiler.h b/libcxx/include/__configuration/compiler.h
index cf459a0619b23..4b6c6cad353e3 100644
--- a/libcxx/include/__configuration/compiler.h
+++ b/libcxx/include/__configuration/compiler.h
@@ -33,8 +33,8 @@
// Warn if a compiler version is used that is not supported anymore
// LLVM RELEASE Update the minimum compiler versions
# if defined(_LIBCPP_CLANG_VER)
-# if _LIBCPP_CLANG_VER < 1800
-# warning "Libc++ only supports Clang 18 and later"
+# if _LIBCPP_CLANG_VER < 1900
+# warning "Libc++ only supports Clang 19 and later"
# endif
# elif defined(_LIBCPP_APPLE_CLANG_VER)
# if _LIBCPP_APPLE_CLANG_VER < 1500
|
|
@llvm/pr-subscribers-libcxx Author: Mark de Wever (mordante) ChangesSince Clang 20 has been release we no longer support Clang 18 per our policy. Note the Clang 18 workarounds will be removed in a follow-up patch. Full diff: https://github.com/llvm/llvm-project/pull/130142.diff 3 Files Affected:
diff --git a/.github/workflows/libcxx-build-and-test.yaml b/.github/workflows/libcxx-build-and-test.yaml
index 5d4394435890a..74889adfa070f 100644
--- a/.github/workflows/libcxx-build-and-test.yaml
+++ b/.github/workflows/libcxx-build-and-test.yaml
@@ -100,10 +100,6 @@ jobs:
- config: 'generic-cxx26'
cc: 'clang-19'
cxx: 'clang++-19'
- # Release transition
- - config: 'generic-cxx23'
- cc: 'clang-18'
- cxx: 'clang++-18'
steps:
- uses: actions/checkout@v4
- name: ${{ matrix.config }}
diff --git a/libcxx/docs/index.rst b/libcxx/docs/index.rst
index e2c62e9ecac02..a8b0d5ce1ee97 100644
--- a/libcxx/docs/index.rst
+++ b/libcxx/docs/index.rst
@@ -131,7 +131,7 @@ velocity, libc++ drops support for older compilers as newer ones are released.
============ =================== ========================== =====================
Compiler Versions Restrictions Support policy
============ =================== ========================== =====================
-Clang 18, 19, 20, 21-git latest two stable releases per `LLVM's release page <https://releases.llvm.org>`_ and the development version
+Clang 19, 20, 21-git latest two stable releases per `LLVM's release page <https://releases.llvm.org>`_ and the development version
AppleClang 15 latest stable release per `Xcode's release page <https://developer.apple.com/documentation/xcode-release-notes>`_
Open XL 17.1.3 (AIX) latest stable release per `Open XL's documentation page <https://www.ibm.com/docs/en/openxl-c-and-cpp-aix>`_
GCC 14 In C++11 or later only latest stable release per `GCC's release page <https://gcc.gnu.org/releases.html>`_
diff --git a/libcxx/include/__configuration/compiler.h b/libcxx/include/__configuration/compiler.h
index cf459a0619b23..4b6c6cad353e3 100644
--- a/libcxx/include/__configuration/compiler.h
+++ b/libcxx/include/__configuration/compiler.h
@@ -33,8 +33,8 @@
// Warn if a compiler version is used that is not supported anymore
// LLVM RELEASE Update the minimum compiler versions
# if defined(_LIBCPP_CLANG_VER)
-# if _LIBCPP_CLANG_VER < 1800
-# warning "Libc++ only supports Clang 18 and later"
+# if _LIBCPP_CLANG_VER < 1900
+# warning "Libc++ only supports Clang 19 and later"
# endif
# elif defined(_LIBCPP_APPLE_CLANG_VER)
# if _LIBCPP_APPLE_CLANG_VER < 1500
|
philnik777
approved these changes
Mar 6, 2025
|
Linaro is working on updating to 19. |
ldionne
approved these changes
Mar 18, 2025
|
Sorry for the delay, our workers are using 19.1.7 now and should pass the next build you do. As of 2 weeks ago there were no problems with the test suite on Arm with this clang, but I am available to debug anything you might find now. |
DavidSpickett
approved these changes
Mar 25, 2025
Thanks a lot for updating the bots! |
DavidSpickett
added a commit
to DavidSpickett/llvm-project
that referenced
this pull request
Mar 27, 2025
clang-19 changed how Arm triples were normalised and so while we supported 18 and 19, we could not hard code the path here. Now that Linaro's bots are running clang-19, and libcxx is going to drop clang-18 support (llvm#130142) I have simplified it by hard coding the path again. I also looked into why this exists in the first place. It was added in https://reviews.llvm.org/D154246 but not questioned at the time. It is due to the way we build compiler-rt, which is due to the final layout we need in the install: 1. The builtins library must be called libclang_rt.builtins.a for clang to find it. There must not be an architecture name in the filename. 2. That builtins library must be directly in lib/, next to picolib's installed files. To achieve #1 we must set LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON. However, that causes the file to be installed in a per-target dir which breaks #2. So to fix that, we move the builtins library up one level into lib/. The alternative is to turn off per-target dirs, which results in a builtin file with an arch in the name, then rename and move that file (since it gets installed into lib/generic/). So in the end, it's the same amount of hacks. I think it's best to keep the one that uses LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON, as this is the recommended way to built these days.
DavidSpickett
added a commit
that referenced
this pull request
Mar 28, 2025
clang-19 changed how Arm triples were normalised and so while we supported 18 and 19, we could not hard code the path here. Now that Linaro's bots are running clang-19, and libcxx is going to drop clang-18 support (#130142) I have simplified it by hard coding the path again. I also looked into why this exists in the first place. It was added in https://reviews.llvm.org/D154246 but not questioned at the time. It is due to the way we build compiler-rt, which is due to the final layout we need in the install: 1. The builtins library must be called libclang_rt.builtins.a for clang to find it. There must not be an architecture name in the filename. 2. That builtins library must be directly in lib/, next to picolib's installed files. To achieve number 1 we must set LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON. However, that causes the file to be installed in a per-target dir which breaks number 2. So to fix that, we move the builtins library up one level into lib/. The alternative is to turn off per-target dirs, which results in a builtin file with an arch in the name, then rename and move that file (since it gets installed into lib/generic/). So in the end, it's the same amount of hacks. I think it's best to keep the one that uses LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON, as this is the recommended way to built these days.
llvm-sync bot
pushed a commit
to arm/arm-toolchain
that referenced
this pull request
Mar 28, 2025
…254) clang-19 changed how Arm triples were normalised and so while we supported 18 and 19, we could not hard code the path here. Now that Linaro's bots are running clang-19, and libcxx is going to drop clang-18 support (llvm/llvm-project#130142) I have simplified it by hard coding the path again. I also looked into why this exists in the first place. It was added in https://reviews.llvm.org/D154246 but not questioned at the time. It is due to the way we build compiler-rt, which is due to the final layout we need in the install: 1. The builtins library must be called libclang_rt.builtins.a for clang to find it. There must not be an architecture name in the filename. 2. That builtins library must be directly in lib/, next to picolib's installed files. To achieve number 1 we must set LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON. However, that causes the file to be installed in a per-target dir which breaks number 2. So to fix that, we move the builtins library up one level into lib/. The alternative is to turn off per-target dirs, which results in a builtin file with an arch in the name, then rename and move that file (since it gets installed into lib/generic/). So in the end, it's the same amount of hacks. I think it's best to keep the one that uses LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON, as this is the recommended way to built these days.
This was referenced Apr 1, 2025
winner245
added a commit
that referenced
this pull request
Apr 13, 2025
`__libcpp_popcount` was previously used as a fallback for `__builtin_popcountg` to ensure compatibility with older compilers (Clang 18 and earlier), as `__builtin_popcountg` became available in Clang 19. Now that support for Clang 18 has been officially dropped in #130142, we can now safely replace all instances of `__libcpp_popcount` with `__builtin_popcountg` and eliminate the fallback logic.
var-const
pushed a commit
to ldionne/llvm-project
that referenced
this pull request
Apr 17, 2025
`__libcpp_popcount` was previously used as a fallback for `__builtin_popcountg` to ensure compatibility with older compilers (Clang 18 and earlier), as `__builtin_popcountg` became available in Clang 19. Now that support for Clang 18 has been officially dropped in llvm#130142, we can now safely replace all instances of `__libcpp_popcount` with `__builtin_popcountg` and eliminate the fallback logic.
winner245
added a commit
that referenced
this pull request
Apr 19, 2025
…3920) `__libcpp_{ctz, clz}` were previously used as fallbacks for `__builtin_{ctzg, clzg}` to ensure compatibility with older compilers (Clang 18 and earlier), as `__builtin_{ctzg, clzg}` became available in Clang 19. Now that support for Clang 18 has been officially dropped in #130142, we can now safely replace all instances of `__libcpp_{ctz, clz}` with `__count{l,r}_zero` (which internally call `__builtin_{ctzg, clzg}` and eliminate the fallback logic. Closes #131179.
IanWood1
pushed a commit
to IanWood1/llvm-project
that referenced
this pull request
May 6, 2025
…m#133920) `__libcpp_{ctz, clz}` were previously used as fallbacks for `__builtin_{ctzg, clzg}` to ensure compatibility with older compilers (Clang 18 and earlier), as `__builtin_{ctzg, clzg}` became available in Clang 19. Now that support for Clang 18 has been officially dropped in llvm#130142, we can now safely replace all instances of `__libcpp_{ctz, clz}` with `__count{l,r}_zero` (which internally call `__builtin_{ctzg, clzg}` and eliminate the fallback logic. Closes llvm#131179.
IanWood1
pushed a commit
to IanWood1/llvm-project
that referenced
this pull request
May 6, 2025
…m#133920) `__libcpp_{ctz, clz}` were previously used as fallbacks for `__builtin_{ctzg, clzg}` to ensure compatibility with older compilers (Clang 18 and earlier), as `__builtin_{ctzg, clzg}` became available in Clang 19. Now that support for Clang 18 has been officially dropped in llvm#130142, we can now safely replace all instances of `__libcpp_{ctz, clz}` with `__count{l,r}_zero` (which internally call `__builtin_{ctzg, clzg}` and eliminate the fallback logic. Closes llvm#131179.
IanWood1
pushed a commit
to IanWood1/llvm-project
that referenced
this pull request
May 6, 2025
…m#133920) `__libcpp_{ctz, clz}` were previously used as fallbacks for `__builtin_{ctzg, clzg}` to ensure compatibility with older compilers (Clang 18 and earlier), as `__builtin_{ctzg, clzg}` became available in Clang 19. Now that support for Clang 18 has been officially dropped in llvm#130142, we can now safely replace all instances of `__libcpp_{ctz, clz}` with `__count{l,r}_zero` (which internally call `__builtin_{ctzg, clzg}` and eliminate the fallback logic. Closes llvm#131179.
# for free
to join this conversation on GitHub.
Already have an account?
# to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Since Clang 20 has been release we no longer support Clang 18 per our policy.
Note the Clang 18 workarounds will be removed in a follow-up patch.