[docs] The stat cache has been removed from the PCH, update the docs to remove mentions of it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175109 91177308-0d34-0410-b5e6-96231b3b80d8

Author: akyrtzi

Diff for: docs/PCHInternals.rst

@@ -92,9 +92,7 @@ the actual precompiled header is required:
 
 .. code-block:: none
 
-  *** PCH Statistics:
-    933 stat cache hits
-    4 stat cache misses
+  *** AST File Statistics:
     895/39981 source location entries read (2.238563%)
     19/15315 types read (0.124061%)
     20/82685 declarations read (0.024188%)
@@ -214,10 +212,7 @@ The source manager block also contains information about all of the headers
 that were included when building the AST file.  This includes information about
 the controlling macro for the header (e.g., when the preprocessor identified
 that the contents of the header dependent on a macro like
-``LLVM_CLANG_SOURCEMANAGER_H``) along with a cached version of the results of
-the ``stat()`` system calls performed when building the AST file.  The latter
-is particularly useful in reducing system time when searching for include
-files.
+``LLVM_CLANG_SOURCEMANAGER_H``).
 
 .. _pchinternals-preprocessor:
 
@@ -425,10 +420,6 @@ file, inherits from all of these abstract classes to provide lazy
 deserialization of Clang's data structures.  ``ASTReader`` implements the
 following abstract classes:
 
-``StatSysCallCache``
-  This abstract interface is associated with the ``FileManager`` class, and is
-  used whenever the file manager is going to perform a ``stat()`` system call.
-
 ``ExternalSLocEntrySource``
   This abstract interface is associated with the ``SourceManager`` class, and
   is used whenever the :ref:`source manager <pchinternals-sourcemgr>` needs to

Diff for: docs/UsersManual.rst

@@ -820,12 +820,7 @@ example, :option:`-isysroot /Developer/SDKs/MacOSX10.4u.sdk` will look for
 Relocatable precompiled headers are intended to be used in a limited
 number of cases where the compilation environment is tightly controlled
 and the precompiled header cannot be generated after headers have been
-installed. Relocatable precompiled headers also have some performance
-impact, because the difference in location between the header locations
-at PCH build time vs. at the time of PCH use requires one of the PCH
-optimizations, ``stat()`` caching, to be disabled. However, this change
-is only likely to affect PCH files that reference a large number of
-headers.
+installed.
 
 Controlling Code Generation
 ---------------------------