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>
- add patch from 2 upstream commits that were not backported to llvm_18
and llvm_19:
41eb186fbb
Fixes build failure with gcc15:
```
In file included from /build/mlir-src-18.1.8/mlir/lib/Dialect/Affine/IR/ValueBoundsOpInterfaceImpl.cpp:9:
/build/mlir-src-18.1.8/mlir/include/mlir/Dialect/Affine/IR/ValueBoundsOpInterfaceImpl.h:31:11:
error: 'int64_t' was not declared in this scope
31 | FailureOr<int64_t> fullyComposeAndComputeConstantDelta(Value value1,
| ^~~~~~~
/build/mlir-src-18.1.8/mlir/include/mlir/Dialect/Affine/IR/ValueBoundsOpInterfaceImpl.h:13:1:
note: 'int64_t' is defined in header '<cstdint>'; this is probably
fixable by adding '#include <cstdint>'
12 | #include "mlir/Support/LogicalResult.h"
+++ |+#include <cstdint>
13 |
```
101109fc54
Fixes failure with gcc15:
```
In file included from /build/mlir-src-19.1.7/mlir/lib/Target/SPIRV/Deserialization/Deserialization.cpp:9:
/build/mlir-src-19.1.7/mlir/include/mlir/Target/SPIRV/Deserialization.h:29:51:
error: 'uint32_t' was not declared in this scope
29 | OwningOpRef<spirv::ModuleOp> deserialize(ArrayRef<uint32_t> binary,
| ^~~~~~~~
/build/mlir-src-19.1.7/mlir/include/mlir/Target/SPIRV/Deserialization.h:18:1:
note: 'uint32_t' is defined in header '<cstdint>'; this is probably
fixable by adding '#include <cstdint>'
17 | #include "mlir/Support/LLVM.h"
+++ |+#include <cstdint>
18 |
```
First patch can be applied with `fetchpatch`, but only on llvm_19, because
of changed include line right above.
So use 2 versions of combined patches with 2 commits.
