================
@@ -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.
----------------
tru wrote:
maybe link to AutoFDO or explain what it's used for here?
https://github.com/llvm/llvm-project/pull/84864
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