[clang] [compiler-rt] [lld] [llvm] [Coverage][WebAssembly] Add initial support for WebAssembly/WASI (PR #111332)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

> I also bisected errors on Windows, down to this commit.
> 
> The errors show up when running the compiler-rt testsuite, like this: https://github.com/mstorsjo/llvm-mingw/actions/runs/11356888872/job/31598676534 A number of tests fail, where `llvm-cov` errors out with `profile uses zlib compression but the profile reader was built without zlib support`.
> 
> This can be reproduced with something as small as `llvm-cov show coverage_comments.cpp.exe -instr-profile coverage_comments.cpp.tmp.profdata`. Binaries of `llvm-cov` from before this change work fine, while binaries from after it produce this error.

This issue can be reproduced with a few prebuilt files: https://martin.st/temp/profile/

Download those three files, build `llvm-cov` (on Linux or anywhere), and execute this:
```
$ llvm-cov show coverage_comments.cpp.exe -instr-profile coverage_comments.cpp.tmp.profdata
```

Before this breaking change, you'll get this:
```
error: C:/path/to/llvm-project/compiler-rt/test/profile/coverage_comments.cpp: No such file or directory
warning: The file 'C:/path/to/llvm-project/compiler-rt/test/profile/coverage_comments.cpp' isn't covered.
```
After this change, you instead get this:
```
error: failed to load coverage: 'coverage_comments.cpp.exe': failed to uncompress data (zlib)
```

Can someone revert this change to get things back into working order?

https://github.com/llvm/llvm-project/pull/111332