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

[Tobias Hieta via cfe-commits]

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@@ -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),
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tru wrote:

I think we can make it clear that perf is only on Linux while SEP is Linux and Windows.

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