| Issue |
126954
|
| Summary |
lld-link library search should be case-insensitive for compatibility with MSVC artifacts
|
| Labels |
lld:COFF
|
| Assignees |
|
| Reporter |
rnk
|
MSVC tools produce `.obj` files that refer to `MSVCRT`, `OLDNAMES`, and `LIBCMT`, but they distribute files with lower-cased names:
```
$ cl -c t.cpp && dumpbin -directives t.obj | grep -i defaul
Microsoft (R) C/C++ Optimizing Compiler Version 19.41.34123 for x64
Copyright (C) Microsoft Corporation. All rights reserved.
t.cpp
/DEFAULTLIB:libcpmt
/DEFAULTLIB:LIBCMT
/DEFAULTLIB:OLDNAMES
$ cl -MD -c t.cpp && dumpbin -directives t.obj | grep -i defaul
Microsoft (R) C/C++ Optimizing Compiler Version 19.41.34123 for x64
Copyright (C) Microsoft Corporation. All rights reserved.
t.cpp
/DEFAULTLIB:msvcprt
/DEFAULTLIB:MSVCRT
/DEFAULTLIB:OLDNAMES
$ ls /c/Program\ Files/Microsoft\ Visual\ Studio/2022/Professional/VC/Tools/MSVC/14.41.34120/lib/x64/
aligned_new.lib libcmt.lib msvcmrtd.lib
...
clang_rt.fuzzer_MT-x86_64.lib libconcrtd1.amd64.pdb oldnames.lib
```
Clang and LLVM use lower-cased filenames for auto-linking:
```
$ git grep -i oldnames ../clang ../llvm
../clang/lib/Driver/ToolChains/Clang.cpp: CmdArgs.push_back("--dependent-lib=oldnames");
...
```
This presents a portability problem when cross-linking for Windows from Linux or other case-sensitive platforms. Ideally, LLD should be able to handle MSVC-produced artifacts as they are. We could make this as simple as checking for lower-cased filenames as part of our `findFile` implementation.
I was almost certain there was already an issue covering this, but github issue search isn't that great, and I hoped that as I started to file this one, it would magically point me to "similar issues", but I've made it this far and it hasn't done that yet, so I'm hitting Create...
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