[PATCH] D124719: [clang,doc] PCH usage documentation update

Ivan Murashko via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Sat Apr 30 13:54:24 PDT 2022

ivanmurashko updated this revision to Diff 426248.
ivanmurashko added a comment.

Minor changes at the doc

  rG LLVM Github Monorepo




Index: clang/docs/UsersManual.rst
--- clang/docs/UsersManual.rst
+++ clang/docs/UsersManual.rst
@@ -1219,23 +1219,22 @@
 Using a PCH File
-A PCH file can then be used as a prefix header when a :option:`-include`
+A PCH file can then be used as a prefix header when a :option:`-include-pch`
 option is passed to ``clang``:
 .. code-block:: console
-  $ clang -include test.h test.c -o test
+  $ clang -include-pch test.h.pch test.c -o test
-The ``clang`` driver will first check if a PCH file for ``test.h`` is
+The ``clang`` driver will check if the PCH file ``test.h.pch`` is
 available; if so, the contents of ``test.h`` (and the files it includes)
-will be processed from the PCH file. Otherwise, Clang falls back to
-directly processing the content of ``test.h``. This mirrors the behavior
-of GCC.
+will be processed from the PCH file. Otherwise, Clang will report an error.
 .. note::
   Clang does *not* automatically use PCH files for headers that are directly
-  included within a source file. For example:
+  included within a source file or indirectly via :option:`-include`.
+  For example:
   .. code-block:: console
@@ -1244,9 +1243,6 @@
     #include "test.h"
     $ clang test.c -o test
-  In this example, ``clang`` will not automatically use the PCH file for
-  ``test.h`` since ``test.h`` was included directly in the source file and not
-  specified on the command line using :option:`-include`.
 Relocatable PCH Files

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