Truncate IR dump basenames to respect NAME_MAX#1650
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npiesco wants to merge 1 commit intorust-lang:mainfrom
Open
Truncate IR dump basenames to respect NAME_MAX#1650npiesco wants to merge 1 commit intorust-lang:mainfrom
npiesco wants to merge 1 commit intorust-lang:mainfrom
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Symbol-mangled Rust names can easily exceed the per-component filename
length limit enforced by most filesystems (255 bytes on ext4/XFS/Btrfs,
143 on HFS+, 255 UTF-16 code units on NTFS), causing `File::create`
in `write_ir_file` to fail with ENAMETOOLONG when `--emit=llvm-ir`
is passed so cg_clif dumps CLIF/vcode per function. The previous code
carried a `FIXME work around filename too long errors` marker.
This change introduces `truncate_ir_basename`: names `\u{2264}` 200
bytes pass through unchanged; longer names are rewritten to
`<first 160 bytes of stem>_h<16-hex-FNV-1a-64 of full stem>.<exts>`.
The hash is computed over the original stem, so the transformation is
deterministic and collision-resistant (any two distinct inputs map to
distinct outputs with overwhelming probability). Extension suffix
chains such as `.opt.clif`, `.unopt.clif`, and `.vcode` are
preserved, so downstream tooling keying off the extension is unaffected.
The function is invoked inside `write_ir_file` so that every caller
(`write_clif_file` for CLIF dumps and the vcode dump in `base.rs`)
benefits uniformly, and the FIXME at the top of `write_clif_file` is
removed.
Author
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@folkertdev @Urgau — tagging you for a second pair of eyes since #1649 closed with a "not quite the right approach" note but no concrete alternative. Open to reshaping on feedback; the core point is that the current |
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Resolves the
// FIXME work around filename too long errorsinsrc/pretty_clif.rs.When
--emit=llvm-iris used with cg_clif, symbol-mangled basenames can exceed the filesystem per-component limit (255B on ext4/XFS/APFS, 143B on HFS+, 255 UTF-16 on NTFS).File::createreturnsENAMETOOLONG; the currentearly_warnpath silently drops the dump.This patch truncates only names that would fail:
Cow).<first 160 bytes of stem>_h<16-hex-FNV-1a-64 over the full stem>.<exts>..opt.clif,.unopt.clif,.vcode) preserved.Called inside
write_ir_file, so bothwrite_clif_fileand the vcode writer inbase.rsbenefit uniformly.Supersedes #1649 (closed). Happy to adjust the shape on review feedback.