[clang] [llvm] Update documentation and release notes for llvm-profgen COFF support (PR #84864)

[Tim Creech via llvm-commits]

================
@@ -2410,20 +2410,35 @@ usual build cycle when using sample profilers for optimization:
 
 1. Build the code with source line table information. You can use all the
    usual build flags that you always build your application with. The only
-   requirement is that you add ``-gline-tables-only`` or ``-g`` to the
-   command line. This is important for the profiler to be able to map
-   instructions back to source line locations.
+   requirement is that DWARF debug info including source line information is
+   generated. This DWARF information is important for the profiler to be able
+   to map instructions back to source line locations.
+
+   On Linux, ``-g`` or just ``-gline-tables-only`` is sufficient:
 
    .. code-block:: console
 
      $ clang++ -O2 -gline-tables-only code.cc -o code
 
+   It is also possible to include DWARF in Windows binaries:
+
+   .. code-block:: console
+
+     $ clang-cl -O2 -gdwarf -gline-tables-only coff-profile.cpp -fuse-ld=lld -link -debug:dwarf
+
 2. Run the executable under a sampling profiler. The specific profiler
    you use does not really matter, as long as its output can be converted
-   into the format that the LLVM optimizer understands. Currently, there
-   exists a conversion tool for the Linux Perf profiler
-   (https://perf.wiki.kernel.org/), so these examples assume that you
-   are using Linux Perf to profile your code.
+   into the format that the LLVM optimizer understands.
+
+   Two such profilers are the the Linux Perf profiler
+   (https://perf.wiki.kernel.org/) and Intel's Sampling Enabling Product (SEP),
+   available as part of `Intel VTune
+   <https://software.intel.com/content/www/us/en/develop/tools/oneapi/components/vtune-profiler.html>`_.
+
+   The LLVM tool ``llvm-profgen`` can convert output of either Perf or SEP. An
+   external tool, AutoFDO, also supports Linux Perf output.
----------------
tcreech-intel wrote:

Yes, probably a good idea to include a link here now that it's the first mention of AutoFDO. Fixed in [a5e879c](https://github.com/llvm/llvm-project/pull/84864/commits/a5e879ce5016fee9cf3109bb9fc7785c396ac509).

https://github.com/llvm/llvm-project/pull/84864