https://github.com/python/cpython/commit/d162c427904e232fec52d8da759caa1bfa4c01b5
commit: d162c427904e232fec52d8da759caa1bfa4c01b5
branch: main
author: Savannah Ostrowski <[email protected]>
committer: savannahostrowski <[email protected]>
date: 2025-11-12T18:09:25Z
summary:
GH-140479: Update JIT builds to use LLVM 21 (#140973)
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2025-11-04-04-57-24.gh-issue-140479.lwQ2v2.rst
M .github/workflows/jit.yml
M PCbuild/get_externals.bat
M Tools/jit/README.md
M Tools/jit/_llvm.py
diff --git a/.github/workflows/jit.yml b/.github/workflows/jit.yml
index 69d900091a3bd1..62325250bd368e 100644
--- a/.github/workflows/jit.yml
+++ b/.github/workflows/jit.yml
@@ -68,7 +68,7 @@ jobs:
- true
- false
llvm:
- - 20
+ - 21
include:
- target: i686-pc-windows-msvc/msvc
architecture: Win32
@@ -138,7 +138,7 @@ jobs:
fail-fast: false
matrix:
llvm:
- - 20
+ - 21
steps:
- uses: actions/checkout@v4
with:
@@ -166,7 +166,7 @@ jobs:
fail-fast: false
matrix:
llvm:
- - 20
+ - 21
steps:
- uses: actions/checkout@v4
with:
@@ -193,7 +193,7 @@ jobs:
fail-fast: false
matrix:
llvm:
- - 20
+ - 21
steps:
- uses: actions/checkout@v4
with:
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2025-11-04-04-57-24.gh-issue-140479.lwQ2v2.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2025-11-04-04-57-24.gh-issue-140479.lwQ2v2.rst
new file mode 100644
index 00000000000000..0a615ed131127f
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2025-11-04-04-57-24.gh-issue-140479.lwQ2v2.rst
@@ -0,0 +1 @@
+Update JIT compilation to use LLVM 21 at build time.
diff --git a/PCbuild/get_externals.bat b/PCbuild/get_externals.bat
index 115203cecc8e48..9d02e2121cc623 100644
--- a/PCbuild/get_externals.bat
+++ b/PCbuild/get_externals.bat
@@ -82,7 +82,7 @@ if NOT "%IncludeLibffi%"=="false" set binaries=%binaries%
libffi-3.4.4
if NOT "%IncludeSSL%"=="false" set binaries=%binaries% openssl-bin-3.0.18
if NOT "%IncludeTkinter%"=="false" set binaries=%binaries% tcltk-8.6.15.0
if NOT "%IncludeSSLSrc%"=="false" set binaries=%binaries% nasm-2.11.06
-if NOT "%IncludeLLVM%"=="false" set binaries=%binaries% llvm-20.1.8.0
+if NOT "%IncludeLLVM%"=="false" set binaries=%binaries% llvm-21.1.4.0
for %%b in (%binaries%) do (
if exist "%EXTERNALS_DIR%\%%b" (
@@ -92,7 +92,7 @@ for %%b in (%binaries%) do (
git clone --depth 1 https://github.com/%ORG%/cpython-bin-deps --branch
%%b "%EXTERNALS_DIR%\%%b"
) else (
echo.Fetching %%b...
- if "%%b"=="llvm-20.1.8.0" (
+ if "%%b"=="llvm-21.1.4.0" (
%PYTHON% -E "%PCBUILD%\get_external.py" --release --organization
%ORG% --externals-dir "%EXTERNALS_DIR%" %%b
) else (
%PYTHON% -E "%PCBUILD%\get_external.py" --binary --organization
%ORG% --externals-dir "%EXTERNALS_DIR%" %%b
diff --git a/Tools/jit/README.md b/Tools/jit/README.md
index d83b09aab59f8c..dd7deb7b256449 100644
--- a/Tools/jit/README.md
+++ b/Tools/jit/README.md
@@ -9,32 +9,32 @@ Python 3.11 or newer is required to build the JIT.
The JIT compiler does not require end users to install any third-party
dependencies, but part of it must be *built* using LLVM[^why-llvm]. You are
*not* required to build the rest of CPython using LLVM, or even the same
version of LLVM (in fact, this is uncommon).
-LLVM version 20 is the officially supported version. You can modify if needed
using the `LLVM_VERSION` env var during configure. Both `clang` and
`llvm-readobj` need to be installed and discoverable (version suffixes, like
`clang-19`, are okay). It's highly recommended that you also have
`llvm-objdump` available, since this allows the build script to dump
human-readable assembly for the generated code.
+LLVM version 21 is the officially supported version. You can modify if needed
using the `LLVM_VERSION` env var during configure. Both `clang` and
`llvm-readobj` need to be installed and discoverable (version suffixes, like
`clang-19`, are okay). It's highly recommended that you also have
`llvm-objdump` available, since this allows the build script to dump
human-readable assembly for the generated code.
It's easy to install all of the required tools:
### Linux
-Install LLVM 20 on Ubuntu/Debian:
+Install LLVM 21 on Ubuntu/Debian:
```sh
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
-sudo ./llvm.sh 20
+sudo ./llvm.sh 21
```
-Install LLVM 20 on Fedora Linux 40 or newer:
+Install LLVM 21 on Fedora Linux 40 or newer:
```sh
-sudo dnf install 'clang(major) = 20' 'llvm(major) = 20'
+sudo dnf install 'clang(major) = 21' 'llvm(major) = 21'
```
### macOS
-Install LLVM 20 with [Homebrew](https://brew.sh):
+Install LLVM 21 with [Homebrew](https://brew.sh):
```sh
-brew install llvm@20
+brew install llvm@21
```
Homebrew won't add any of the tools to your `$PATH`. That's okay; the build
script knows how to find them.
@@ -43,18 +43,18 @@ Homebrew won't add any of the tools to your `$PATH`. That's
okay; the build scri
LLVM is downloaded automatically (along with other external binary
dependencies) by `PCbuild\build.bat`.
-Otherwise, you can install LLVM 20 [by searching for it on LLVM's GitHub
releases page](https://github.com/llvm/llvm-project/releases?q=20), clicking on
"Assets", downloading the appropriate Windows installer for your platform
(likely the file ending with `-win64.exe`), and running it. **When installing,
be sure to select the option labeled "Add LLVM to the system PATH".**
+Otherwise, you can install LLVM 21 [by searching for it on LLVM's GitHub
releases page](https://github.com/llvm/llvm-project/releases?q=21), clicking on
"Assets", downloading the appropriate Windows installer for your platform
(likely the file ending with `-win64.exe`), and running it. **When installing,
be sure to select the option labeled "Add LLVM to the system PATH".**
Alternatively, you can use [chocolatey](https://chocolatey.org):
```sh
-choco install llvm --version=20.1.8
+choco install llvm --version=21.1.0
```
### Dev Containers
If you are working on CPython in a [Codespaces
instance](https://devguide.python.org/getting-started/setup-building/#using-codespaces),
there's no
-need to install LLVM as the Fedora 42 base image includes LLVM 20 out of the
box.
+need to install LLVM as the Fedora 43 base image includes LLVM 21 out of the
box.
## Building
diff --git a/Tools/jit/_llvm.py b/Tools/jit/_llvm.py
index f1b0ad3f5dbc43..0b9cb5192f1b75 100644
--- a/Tools/jit/_llvm.py
+++ b/Tools/jit/_llvm.py
@@ -11,8 +11,8 @@
import _targets
-_LLVM_VERSION = "20"
-_EXTERNALS_LLVM_TAG = "llvm-20.1.8.0"
+_LLVM_VERSION = "21"
+_EXTERNALS_LLVM_TAG = "llvm-21.1.4.0"
_P = typing.ParamSpec("_P")
_R = typing.TypeVar("_R")
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