…Stream.

CachedFileStream has previously performed the commit step in its
destructor, but this means its only recourse for error handling is
report_fatal_error. Modify this to add an explicit commit() method, and
call this in the appropriate places with appropriate error handling for
the location.

Currently the destructor of CacheStream gives an assert failure in Debug
builds if commit() was not called. This will help track down any
remaining uses of the API that assume the old destructior behaviour. In
Release builds we fall back to the previous behaviour and call
report_fatal_error if the commit fails.

This is version 2 of this PR, superseding reverted PR
https://github.com/llvm/llvm-project/pull/115331 . I have incorporated a
change to the testcase to make it more reliable on Windows, as well as
two follow-up changes
(https://github.com/llvm/llvm-project/commit/df79000896101acc9b8d7435e59f767b36c00ac8
and
https://github.com/llvm/llvm-project/commit/b0baa1d8bd68a2ce2f7c5f2b62333e410e9122a1)
that were also reverted when 115331 was reverted.

---------

Co-authored-by: Augie Fackler <augie@google.com>
Co-authored-by: Vitaly Buka <vitalybuka@google.com>

This reverts commit ce9e1d3c15ed6290f1cb07b482939976fa8115cd.

The unittest added in this commit seems to be flaky causing random failure on buildbots:
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13235
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13232
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13228
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13224
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13220
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13210
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13208
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13207
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13202
 - https://lab.llvm.org/buildbot/#/builders/46/builds/13196
and
 - https://lab.llvm.org/buildbot/#/builders/180/builds/14266
 - https://lab.llvm.org/buildbot/#/builders/180/builds/14254
 - https://lab.llvm.org/buildbot/#/builders/180/builds/14250
 - https://lab.llvm.org/buildbot/#/builders/180/builds/14245
 - https://lab.llvm.org/buildbot/#/builders/180/builds/14244
 - https://lab.llvm.org/buildbot/#/builders/180/builds/14226

…Stream.

CachedFileStream has previously performed the commit step in its
destructor, but this means its only recourse for error handling is
report_fatal_error. Modify this to add an explicit commit() method, and
call this in the appropriate places with appropriate error handling for
the location.

Currently the destructor of CacheStream gives an assert failure in Debug
builds if commit() was not called. This will help track down any
remaining uses of the API that assume the old destructior behaviour. In
Release builds we fall back to the previous behaviour and call
report_fatal_error if the commit fails.

Those fixes were taken from https://reviews.llvm.org/D137338

This reverts commit 34108082947c964ae9bbfcd9808f2fd31c0d672f with fixes.

Breaks build of LLVMgold here:
```
/repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1108:19: error: no matching function for call to 'localCache'
    Cache = check(localCache("ThinLTO", "Thin", options::cache_dir, AddBuffer));
                  ^~~~~~~~~~
/repositories/llvm-project/llvm/include/llvm/Support/Caching.h:72:21: note: candidate function not viable: no known conversion from '(lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1102:20)' to 'llvm::AddBufferFn' (aka 'function<void (unsigned int, const llvm::Twine &, std::unique_ptr<MemoryBuffer>)>') for 4th argument
Expected<FileCache> localCache(
                    ^
/repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1110:18: error: no viable conversion from '(lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20)' to 'llvm::AddStreamFn' (aka 'function<Expected<std::unique_ptr<CachedFileStream>> (unsigned int, const llvm::Twine &)>')
  check(Lto->run(AddStream, Cache));
                 ^~~~~~~~~
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/std_function.h:375:7: note: candidate constructor not viable: no known conversion from '(lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20)' to 'std::nullptr_t' for 1st argument
      function(nullptr_t) noexcept
      ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/std_function.h:386:7: note: candidate constructor not viable: no known conversion from '(lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20)' to 'const std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream>> (unsigned int, const llvm::Twine &)> &' for 1st argument
      function(const function& __x)
      ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/std_function.h:404:7: note: candidate constructor not viable: no known conversion from '(lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20)' to 'std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream>> (unsigned int, const llvm::Twine &)> &&' for 1st argument
      function(function&& __x) noexcept
      ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/std_function.h:435:2: note: candidate template ignored: requirement '_Callable<(lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20) &, (lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20), std::__invoke_result<(lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20) &, unsigned int, const llvm::Twine &>>::value' was not satisfied [with _Functor = (lambda at /repositories/llvm-project/llvm/tools/gold/gold-plugin.cpp:1094:20) &]
        function(_Functor&& __f)
        ^
/repositories/llvm-project/llvm/include/llvm/LTO/LTO.h:278:25: note: passing argument to parameter 'AddStream' here
  Error run(AddStreamFn AddStream, FileCache Cache = nullptr);
                        ^

```

This reverts commit 387620aa8cea33174b6c1fb80c1af713fee732ac.

This reverts commit eef5405f74ae208e3e2eb7daacecac923d7338f2.

This reverts commit 531ed6d5aa65f41c6dfe2e74905d5c6c88fc95a7.

Currently the lto native object files have names like main.exe.lto.1.obj. In
PDB, those names are used as names for each compiland. Microsoft’s tool
SizeBench uses those names to present to users the size of each object files.
So, names like main.exe.lto.1.obj is not user friendly.

This patch makes the lto native object file names more readable by using
the bitcode file names as part of the file names. For example, if the input
bitcode file has path like "path/to/foo.obj", its corresponding lto native
object file path would be "path/to/main.exe.lto.foo.obj". Since the lto native
object file name only bothers PDB, this patch only changes the lld-linker's
behavior.

Reviewed By: tejohnson, MaskRay, #lld-macho

Differential Revision: https://reviews.llvm.org/D137217