| Issue |
182493
|
| Summary |
flang doesn't take --sysroot as an argument, but crosscompiling runtimes assumes it does
|
| Labels |
flang
|
| Assignees |
|
| Reporter |
berolinux
|
flang doesn't understand --sysroot as an argument - but if I try to crosscompile runtimes that require flang using the `LLVM_ENABLE_RUNTIMES`/`LLVM_RUNTIME_TARGETS`/`LLVM_ENABLE_PER_TARGET_RUNTIME_DIR` mechanism, that puts --sysroot on the command line for flang invocations.
```
FAILED: [code=1] flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90-pp.f90 flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90.o.ddi
/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/build/bin/flang --target=aarch64-openmandriva-linux-gnu -cpp -D_GLIBCXX_NO_ASSERTIONS -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang-rt/include -I/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang-rt/../flang/include -I/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/build/runtimes/runtimes-aarch64-openmandriva-linux-gnu-bins/flang-rt -isysroot /usr/aarch64-openmandriva-linux-gnu -O2 -g -Jflang-rt/lib/runtime -fno-lto "-D_GLIBCXX_THROW_OR_ABORT(_EXC)=(__builtin_abort())" -E /home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90 > flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90-pp.f90 && /usr/bin/cmake -E cmake_ninja_depends --tdi=flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/FortranDependInfo.json --lang=Fortran --src="" --out=flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90-pp.f90 --dep=flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90-pp.f90.d --obj=flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90.o --ddi=flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90.o.ddi --src-orig=/home/bero/abf/llvm/BUILD/llvm-22.1.0_rc3-build/llvm-project-llvmorg-22.1.0-rc3/flang/module/iso_fortran_env_impl.f90
flang-22: error: unknown argument '--sysroot'; did you mean '-isysroot'?
```
Either flang should accept `--sysroot` (probably makes most sense also for gfortran compatibility - and Options.td looks like it is actually intended, given _sysroot_EQ Visibility includes FlangOption), or the cmake files should stop putting --sysroot into the flags for flang calls.
I'm not sure how to fix this properly; my ugly interim workaround is
```
diff -up llvm-project-llvmorg-22.1.0-rc3/clang/lib/Driver/Driver.cpp.omv~ llvm-project-llvmorg-22.1.0-rc3/clang/lib/Driver/Driver.cpp
--- llvm-project-llvmorg-22.1.0-rc3/clang/lib/Driver/Driver.cpp.omv~ 2026-02-18 00:30:41.724650451 +0100
+++ llvm-project-llvmorg-22.1.0-rc3/clang/lib/Driver/Driver.cpp 2026-02-18 01:28:05.216128285 +0100
@@ -276,6 +276,10 @@ InputArgList Driver::ParseArgStrings(Arr
for (const Arg *A : Args.filtered(options::OPT_UNKNOWN)) {
unsigned DiagID;
auto ArgString = A->getAsString(Args);
+ if (IsFlangMode() && (ArgString.find("--sysroot") != std::string::npos || ArgString.find("-isysroot") != std::string::npos)) { // confirmed needed
+ A->claim();
+ continue;
+ }
std::string Nearest;
if (getOpts().findNearest(ArgString, Nearest, VisibilityMask) > 1) {
if (IsFlangMode()) {
```
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