From d85983ece7223d733ab87b0b9a8cca3aa246a406 Mon Sep 17 00:00:00 2001
From: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Date: Sat, 1 Mar 2014 14:12:33 +0100
Subject: [PATCH] Introduce Q_DECL_CONST_FUNCTION and Q_DECL_PURE_FUNCTION

That expand to __attribute__((const)) and ((pure)). A "const" function
is a function allowed to examine only its arguments, without modifying
them. A "pure" function is also allowed to read memory.

Currently working only on GCC/ICC/Clang, MSVC lacks these.

Change-Id: Ie60a0847b193fb88e116f61611dc571296a3df1c
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
---
 doc/global/qt-cpp-defines.qdocconf      | 2 ++
 src/corelib/global/qcompilerdetection.h | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/doc/global/qt-cpp-defines.qdocconf b/doc/global/qt-cpp-defines.qdocconf
index bbf1dda2e67..b2205f54acc 100644
--- a/doc/global/qt-cpp-defines.qdocconf
+++ b/doc/global/qt-cpp-defines.qdocconf
@@ -27,9 +27,11 @@ Cpp.ignoretokens        += \
                           Q_CORE_EXPORT_INLINE \
                           Q_DBUS_EXPORT \
                           Q_DECL_CONSTEXPR \
+                          Q_DECL_CONST_FUNCTION \
                           Q_DECL_DEPRECATED \
                           Q_DECL_NOEXCEPT \
                           Q_DECL_NOTHROW \
+                          Q_DECL_PURE_FUNCTION \
                           Q_DECL_UNUSED \
                           Q_DECLARATIVE_EXPORT \
                           Q_EXPLICIT \
diff --git a/src/corelib/global/qcompilerdetection.h b/src/corelib/global/qcompilerdetection.h
index 1eb442aa5f6..a9f143502ea 100644
--- a/src/corelib/global/qcompilerdetection.h
+++ b/src/corelib/global/qcompilerdetection.h
@@ -200,6 +200,8 @@
 #  define Q_UNLIKELY(expr)  __builtin_expect(!!(expr), false)
 #  define Q_NORETURN        __attribute__((__noreturn__))
 #  define Q_REQUIRED_RESULT __attribute__ ((__warn_unused_result__))
+#  define Q_DECL_PURE_FUNCTION __attribute__((pure))
+#  define Q_DECL_CONST_FUNCTION __attribute__((const))
 #  if !defined(QT_MOC_CPP)
 #    define Q_PACKED __attribute__ ((__packed__))
 #    ifndef __ARM_EABI__
@@ -975,6 +977,12 @@
 #ifndef Q_DECL_NS_RETURNS_AUTORELEASED
 #  define Q_DECL_NS_RETURNS_AUTORELEASED
 #endif
+#ifndef Q_DECL_PURE_FUNCTION
+#  define Q_DECL_PURE_FUNCTION
+#endif
+#ifndef Q_DECL_CONST_FUNCTION
+#  define Q_DECL_CONST_FUNCTION Q_DECL_PURE_FUNCTION
+#endif
 
 /*
    Workaround for static const members on MSVC++.