cmake: add command line options to output script profiling data

For users of CMake who want to optimize their scripts if they take a
while to run, this commit adds the ability to output profiling data.

To enable this output, it adds the two command line parameters
to select the output path and format.

This commit adds the first profiling format of type ``google-trace``,
which is the output is a JSON file containing Duration events as per the
Google Trace Format specification:

https://docs.google.com/document/d/1CvAClvFfyA5R-
PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview#

1 files changed, 14 insertions, 0 deletions

diff --git a/Help/manual/cmake.1.rst b/Help/manual/cmake.1.rst
index 44b1f2f..429cba4 100644
--- a/Help/manual/cmake.1.rst
+++ b/Help/manual/cmake.1.rst
@@ -356,6 +356,20 @@ Options
  in :variable:`CMAKE_SOURCE_DIR` and :variable:`CMAKE_BINARY_DIR`.
  This flag tells CMake to warn about other files as well.
 
+``--profiling-output=<path>``
+ Used in conjuction with ``--profiling-format`` to output to a given path.
+
+``--profiling-format=<file>``
+ Enable the output of profiling data of CMake script in the given format.
+
+ This can aid performance analysis of CMake scripts executed. Third party
+ applications should be used to process the output into human readable format.
+
+ Currently supported values are:
+ ``google-trace`` Outputs in Google Trace Format, which can be parsed by the
+ about:tracing tab of Google Chrome or using a plugin for a tool like Trace
+ Compass.
+
 .. _`Build Tool Mode`:
 
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