[PATCH] D95038: [OpenCL][Docs] Describe tablegen BIFs declaration

[Anastasia Stulova via Phabricator via cfe-commits]

Anastasia created this revision.
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Herald added subscribers: ebevhan, yaxunl.
Anastasia requested review of this revision.

Added documentation for the fast builtin function declaration with `-fdeclare-opencl-builtins`.


https://reviews.llvm.org/D95038

Files:
  clang/docs/OpenCLSupport.rst
  clang/docs/UsersManual.rst


Index: clang/docs/UsersManual.rst
===================================================================
--- clang/docs/UsersManual.rst
+++ clang/docs/UsersManual.rst
@@ -3021,6 +3021,11 @@
 
      $ clang -target spir-unknown-unknown -c -emit-llvm -Xclang -finclude-default-header -fmodules -fimplicit-module-maps -fmodules-cache-path=<path to the generated module> test.cl
 
+Another way to circumvent long parsing latency for the OpenCL builtin
+declarations is to use mechanism enabled by ``-fdeclare-opencl-builtins`` flag
+that is available as an experimental feature (see more information in
+:doc:`OpenCLSupport`).
+
 OpenCL Extensions
 -----------------
 
Index: clang/docs/OpenCLSupport.rst
===================================================================
--- clang/docs/OpenCLSupport.rst
+++ clang/docs/OpenCLSupport.rst
@@ -112,6 +112,25 @@
 <https://lists.llvm.org/mailman/listinfo/cfe-dev>`_ or via `Bugzilla
 <https://bugs.llvm.org/>`__.
 
+Fast builtin function declaration
+---------------------------------
+
+In addition to regular header includes with builtin types/functions using
+``-finclude-default-header`` explained in :doc:`UsersManual` clang
+support fast mechanism to declare builtin functions with
+``-fdeclare-opencl-builtins``. This does not declare the builtin types and
+therefore it has to be used in combination with ``-finclude-default-header``
+if full functionality is required.
+
+**Example of Use**:
+
+    .. code-block:: console
+ 
+      $ clang -Xclang -finclude-default-header test.cl
+
+Note that this is a frontend-only flag and therefore it requires the use of
+flags that forward options to the frontend, e.g. ``-cc1`` or ``-Xclang``.
+
 C++ libraries for OpenCL
 ------------------------
 


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