[llvm] Strip the full path from __FILE__ in the LDBG macro and keep only the filename (PR #150677)

[Mehdi Amini via llvm-commits]

================
@@ -29,7 +29,15 @@ namespace llvm {
 #define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE)                            \
   for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c;  \
        _c = false)                                                             \
-  ::llvm::impl::LogWithNewline(TYPE, __FILE__, __LINE__, (STREAM))
+  ::llvm::impl::LogWithNewline(                                                \
+      TYPE,                                                                    \
+      [] {                                                                     \
----------------
joker-eph wrote:

I don't think it can be constexpr evaluated in this case?

```
include/llvm/Support/DebugLog.h:48:27: error: constexpr variable 'filename' must be initialized by a constant expression
   48 |     constexpr const char *filename  =
      |                           ^
   49 |       ::llvm::impl::LogWithNewline::getFileName(file);
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/llvm/Support/DebugLog.h:49:49: note: function parameter 'file' with unknown value cannot be used in a constant expression
   49 |       ::llvm::impl::LogWithNewline::getFileName(file);
      |                                                 ^
include/llvm/Support/DebugLog.h:45:64: note: declared here
   45 |   constexpr LogWithNewline(const char *debug_type, const char *file, int line,
      |                                                                ^
1 error generated.
```
```

https://github.com/llvm/llvm-project/pull/150677