Acture
1ba36147a8
Wire flang into llvmPackages as a first-class Fortran compiler. flang
is built standalone on top of the LLVM/clang package set rather than
bundled into the llvm derivation, with passthru metadata
(`langFortran`, `isFlang`, `isClang`, `hardeningUnsupportedFlags`) so
cc-wrapper and downstream tooling can detect and adapt to it.
Driver compatibility patches backported from upstream are applied
selectively per LLVM version:
* `use-xflang-in-diagnostics` is applied to LLVM 20 and newer; it
teaches the driver to suggest `-Xflang` instead of `-Xclang` in
error messages for options only available to `flang -fc1`.
* `warn-on-fbuiltin-and-fno-builtin` and
`accept-and-ignore-some-gfortran-optimization-flags` are applied
to LLVM 20 and 21 only. LLVM 22 has equivalent behaviour merged
upstream (`warn_drv_invalid_argument_for_flang` and
`clang_ignored_gcc_optimization_f_Group` handling in
clang/lib/Driver/ToolChains/Flang.cpp), so the patches are skipped
there.
Patches live under pkgs/development/compilers/llvm/21/flang/ and are
shared across versions via patches.nix. They are applied to a private
libclang variant rather than the flang source tree because standalone
flang resolves driver/option definitions through the installed libclang
package.
Two focused passthru tests are added:
* `compile-smoke` exercises basic compilation and `@response-file`
handling.
* `driver-flags` covers wrapper flag isolation
(`NIX_CFLAGS_COMPILE` must not leak into flang;
`NIX_FFLAGS_COMPILE` must reach it), the backported driver
diagnostics, and regression coverage for previously hard-erroring
flags.
Build on the earlier standalone flang work by @picostove.
Co-authored-by: stove <stove@rivosinc.com>
Co-authored-by: acture <acture@gmail.com>
Co-authored-by: Alyssa Ross <hi@alyssa.is>
93 lines
2.8 KiB
Nix
93 lines
2.8 KiB
Nix
{
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runCommand,
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flang,
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}:
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let
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flangExe = "${flang}/bin/flang";
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writeHello = ''
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cat > hello.f90 <<'EOF'
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program hello
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end program hello
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EOF
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'';
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in
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{
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compile-smoke = runCommand "flang-compile-smoke" { } ''
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set -euo pipefail
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${writeHello}
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${flangExe} -c hello.f90 -o compile.o
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[ -f compile.o ]
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cat > args.rsp <<'EOF'
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-c
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hello.f90
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-o
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response.o
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EOF
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${flangExe} @args.rsp
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[ -f response.o ]
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touch $out
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'';
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driver-flags = runCommand "flang-driver-flags" { } ''
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set -euo pipefail
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${writeHello}
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${flangExe} -### -c hello.f90 > no-seed.log 2>&1
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if grep -F -- "-frandom-seed=" no-seed.log; then
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echo "wrapper unexpectedly injected -frandom-seed" >&2
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exit 1
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fi
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# Confirm that user-supplied NIX_CFLAGS_COMPILE does not leak into the
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# Fortran wrapper invocation: the wrapper must source flags from
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# NIX_FFLAGS_COMPILE only, so a marker placed in NIX_CFLAGS_COMPILE
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# must not appear in the resulting flang command line.
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NIX_CFLAGS_COMPILE="-Icflags-leak-marker-include" \
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${flangExe} -### -c hello.f90 > cflags-isolation.log 2>&1
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if grep -F -- "cflags-leak-marker-include" cflags-isolation.log; then
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echo "NIX_CFLAGS_COMPILE leaked into the flang wrapper" >&2
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exit 1
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fi
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# Confirm that NIX_FFLAGS_COMPILE is the user-facing channel for
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# Fortran flags and flows through to the driver.
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NIX_FFLAGS_COMPILE="-Iffflags-marker-include" \
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${flangExe} -### -c hello.f90 > fflags-passthrough.log 2>&1
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grep -F -- "ffflags-marker-include" fflags-passthrough.log
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${flangExe} -### -fbuiltin -fno-builtin hello.f90 > builtin.log 2>&1
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grep -F -- "warning: '-fbuiltin' is not valid for Fortran" builtin.log
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grep -F -- "warning: '-fno-builtin' is not valid for Fortran" builtin.log
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if grep -F -- "error: unknown argument" builtin.log; then
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echo "builtin compatibility flags unexpectedly failed" >&2
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exit 1
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fi
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${flangExe} -### -fexpensive-optimizations hello.f90 > ignored-flag.log 2>&1
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grep -F -- "optimization flag '-fexpensive-optimizations' is not supported" ignored-flag.log
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if grep -F -- "error: unknown argument" ignored-flag.log; then
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echo "ignored gfortran-style flag unexpectedly failed" >&2
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exit 1
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fi
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if ${flangExe} -### -complex-range=full hello.f90 > suggestion.log 2>&1; then
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echo "expected -complex-range=full to fail at the driver layer" >&2
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exit 1
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fi
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grep -F -- "error: unknown argument '-complex-range=full'" suggestion.log
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grep -F -- "did you mean '-Xflang -complex-range=full'" suggestion.log
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if grep -F -- "-Xclang -complex-range=full" suggestion.log; then
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echo "driver suggested -Xclang instead of -Xflang" >&2
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exit 1
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fi
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touch $out
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'';
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}
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