From 07e831d7ff0662069491c22af953f4d6a9e2f3d9 Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Sat, 19 Oct 2013 17:00:39 -0400
Subject: [PATCH] Declare qregister[u]int, an integer the size of the machine's
 word

In almost all platforms, sizeof(qregisterint) == sizeof(void*) ==
sizeof(qptrdiff). It's different for architectures that have a pointer
with a size different from the machine word. This allows us to declare
variables of the most optimal size, even if the pointers are too wide or
too narrow.

The only currently-known architectures to match that case are the ILP32
builds on x86-64 (a.k.a "x32") and IA-64 (option -milp32, only available
on HP-UXi), which have 64-bit registers but 32-bit pointers.

Change-Id: I0f126b70ea9ea326bd3143797287e4b98210d36d
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
---
 src/corelib/global/qglobal.h             |  2 ++
 src/corelib/global/qprocessordetection.h | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index e68246e607..1e9b20757d 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -437,6 +437,8 @@ template <>    struct QIntegerForSize<2> { typedef quint16 Unsigned; typedef qin
 template <>    struct QIntegerForSize<4> { typedef quint32 Unsigned; typedef qint32 Signed; };
 template <>    struct QIntegerForSize<8> { typedef quint64 Unsigned; typedef qint64 Signed; };
 template <class T> struct QIntegerForSizeof: QIntegerForSize<sizeof(T)> { };
+typedef QIntegerForSize<Q_PROCESSOR_WORDSIZE>::Signed qregisterint;
+typedef QIntegerForSize<Q_PROCESSOR_WORDSIZE>::Unsigned qregisteruint;
 typedef QIntegerForSizeof<void*>::Unsigned quintptr;
 typedef QIntegerForSizeof<void*>::Signed qptrdiff;
 typedef qptrdiff qintptr;
diff --git a/src/corelib/global/qprocessordetection.h b/src/corelib/global/qprocessordetection.h
index 623e30aa06..a5eff7c7ce 100644
--- a/src/corelib/global/qprocessordetection.h
+++ b/src/corelib/global/qprocessordetection.h
@@ -196,6 +196,7 @@
 #  define Q_PROCESSOR_X86       6
 #  define Q_PROCESSOR_X86_64
 #  define Q_BYTE_ORDER Q_LITTLE_ENDIAN
+#  define Q_PROCESSOR_WORDSIZE   8
 
 /*
     Itanium (IA-64) family, no revisions or variants
@@ -204,6 +205,7 @@
 */
 #elif defined(__ia64) || defined(__ia64__) || defined(_M_IA64)
 #  define Q_PROCESSOR_IA64
+#  define Q_PROCESSOR_WORDSIZE   8
 // Q_BYTE_ORDER not defined, use endianness auto-detection
 
 /*
@@ -324,4 +326,23 @@
 #  endif
 #endif
 
+/*
+   Define Q_PROCESSOR_WORDSIZE to be the size of the machine's word (usually,
+   the size of the register). On some architectures where a pointer could be
+   smaller than the register, the macro is defined above.
+
+   Try our best to define it to a literal, so it can be used in the preprocessor,
+   but fall back to sizeof(void*) on practically every 32-bit build.
+*/
+#ifndef Q_PROCESSOR_WORDSIZE
+#  ifdef __SIZEOF_POINTER__
+     /* GCC & friends define this */
+#    define Q_PROCESSOR_WORDSIZE        __SIZEOF_POINTER__
+#  elif defined(_LP64) || defined(__LP64__) || defined(WIN64) || defined(_WIN64)
+#    define Q_PROCESSOR_WORDSIZE        8
+#  else
+#    define Q_PROCESSOR_WORDSIZE        sizeof(void*)
+#  endif
+#endif
+
 #endif // QPROCESSORDETECTION_H