[GR-69068][Native Image] "Unable to detect supported DARWIN native software development toolchain" due to broken regex

[lf-]

Describe the Issue

Due to the following regex that assumes that Apple is the only possible clang vendor on macOS:

graal/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/c/codegen/CCompilerInvoker.java

Line 302 in 2b5956d

while (scanner.findInLine("Apple (clang|LLVM) version ") == null) {

The following error can occur when using a source build of clang (not from Apple; for example from nixpkgs):

[nix-shell:~/co/flower]$ native-image Foo
Warning: Environment variable 'MACOSX_DEPLOYMENT_TARGET_FOR_TARGET' is undefined and therefore not available during image build-time.
Warning: Environment variable 'DEVELOPER_DIR_FOR_BUILD' is undefined and therefore not available during image build-time.
Warning: Environment variable 'DEVELOPER_DIR_FOR_TARGET' is undefined and therefore not available during image build-time.
Warning: Environment variable 'MACOSX_DEPLOYMENT_TARGET_FOR_BUILD' is undefined and therefore not available during image build-time.
========================================================================================================================
GraalVM Native Image: Generating 'foo' (executable)...
========================================================================================================================
[1/8] Initializing...
                                                                                    (0.0s @ 0.08GB)
Error: Unable to detect supported DARWIN native software development toolchain.
Querying with command '/nix/store/yr2068d9m3nsc3g5gbjgj1n3fbr9rb89-clang-wrapper-19.1.7/bin/cc -v' prints:
  clang version 19.1.7
  Target: arm64-apple-darwin24.6.0
  Thread model: posix
  InstalledDir: /nix/store/p0y4nlhvjc8q7kgcj3w554vxg2h9mb0s-clang-19.1.7/bin
Error: To prevent native-toolchain checking provide command-line option -H:-CheckToolchain
------------------------------------------------------------------------------------------------------------------------
                         0.1s (4.8% of total time) in 6 GCs | Peak RSS: 0.44GB | CPU load: 4.53
========================================================================================================================
Failed generating 'foo' after 0.8s.

Using the latest version of GraalVM can resolve many issues.

• I tried with the latest version of GraalVM.

GraalVM Version

openjdk version "24.0.2" 2025-07-15
OpenJDK Runtime Environment GraalVM CE 24.0.2+11.1 (build 24.0.2+11-jvmci-b01)
OpenJDK 64-Bit Server VM GraalVM CE 24.0.2+11.1 (build 24.0.2+11-jvmci-b01, mixed mode, sharing)

Operating System and Version

macOS 15.6.1

Build Command

native-image Foo

where Foo.class is a hello world.

Expected Behavior

Should believe in my toolchain.

Actual Behavior

Error: Unable to detect supported DARWIN native software development toolchain.
Querying with command '/nix/store/yr2068d9m3nsc3g5gbjgj1n3fbr9rb89-clang-wrapper-19.1.7/bin/cc -v' prints:
  clang version 19.1.7
  Target: arm64-apple-darwin24.6.0
  Thread model: posix
  InstalledDir: /nix/store/p0y4nlhvjc8q7kgcj3w554vxg2h9mb0s-clang-19.1.7/bin
Error: To prevent native-toolchain checking provide command-line option -H:-CheckToolchain

Steps to Reproduce

$ nix-shell -p graalvmPackages.graalvm-ce
# gives you not-apple clang and a copy of graal

$ native-image Foo

Additional Context

No response

Build Log Output and Error Messages

see above

[tarekelhaddadi]

Hi @lf- ,

Thank you for reaching out to us about this.
We will look into it and I'll make sure to keep you updated.

[tarekelhaddadi]

hi @lf-
GraalVM Native Image toolchain detection is strict by design to ensure stability and compatibility on macOS. If you want to use a non-Apple or custom clang build, you can bypass the check with -H:-CheckToolchain. However, this is recommended if you have verified compatibility with your project.