[rtems commit] score: More strict RTEMS_DEQUALIFY implementation.

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    80ad7090ab3e101e55cb7f7f8ee00c1f57f97c16
Changeset: http://git.rtems.org/rtems/commit/?id=80ad7090ab3e101e55cb7f7f8ee00c1f57f97c16

Author:    Pavel Pisa <pisa at cmp.felk.cvut.cz>
Date:      Mon Sep  8 14:13:31 2014 +0200

score: More strict RTEMS_DEQUALIFY implementation.

This implementation is able to catch cast to type
which differs not only in qualifiers. The error
diagnostic message when used in function is self
descriptive. Macro is compatible with used in initializers
but there message about not constant initial value
signals types incompatibility.

The actual implementation does not distinguish between
volatile and const removal.

---

 cpukit/score/include/rtems/score/basedefs.h |   54 ++++++++++++++++++++++++++-
 1 files changed, 53 insertions(+), 1 deletions(-)

diff --git a/cpukit/score/include/rtems/score/basedefs.h b/cpukit/score/include/rtems/score/basedefs.h
index 361f514..12480a8 100644
--- a/cpukit/score/include/rtems/score/basedefs.h
+++ b/cpukit/score/include/rtems/score/basedefs.h
@@ -191,7 +191,7 @@
  *  This can occur when reading volatile device memory or skipping arguments
  *  in a variable argument method.
  */
-#if defined(__GNUC__)        
+#if defined(__GNUC__)
   #define RTEMS_COMPILER_UNUSED_ATTRIBUTE __attribute__((unused))
 #else
   #define RTEMS_COMPILER_UNUSED_ATTRIBUTE
@@ -227,6 +227,39 @@
 #define RTEMS_CONTAINER_OF( _m, _type, _member_name ) \
   ( (_type *) ( (uintptr_t) ( _m ) - offsetof( _type, _member_name ) ) )
 
+#ifdef __cplusplus
+#define RTEMS_DEQUALIFY_DEPTHX( _ptr_level, _type, _var ) \
+            (const_cast<_type>( _var ))
+#else /* Standard C code */
+
+/* The reference type idea based on libHX by Jan Engelhardt */
+#define RTEMS_TYPEOF_REFX(_ptr_level, _ptr_type) \
+  typeof(_ptr_level(union { int z; typeof(_ptr_type) x; }){0}.x)
+
+#if defined(__GNUC__) && !defined(ASM)
+#if  ((__GNUC__ * 1000 + __GNUC_MINOR__) >= 4004)
+extern void* RTEMS_DEQUALIFY_types_not_compatible(void)
+  __attribute__((error ("RTEMS_DEQUALIFY types differ not only by volatile and const")));
+#else
+extern void RTEMS_DEQUALIFY_types_not_compatible(void);
+#endif
+#define RTEMS_DEQUALIFY_DEPTHX( _ptr_level, _type, _var ) ( \
+    __builtin_choose_expr( __builtin_types_compatible_p ( \
+        RTEMS_TYPEOF_REFX( _ptr_level, _var ), \
+        RTEMS_TYPEOF_REFX( _ptr_level, _type ) \
+      ) || __builtin_types_compatible_p ( _type, void * ), \
+    (_type)(_var), \
+    RTEMS_DEQUALIFY_types_not_compatible() \
+  ) \
+)
+#endif /*__GNUC__*/
+#endif /*__cplusplus*/
+
+#ifndef RTEMS_DECONST
+#ifdef RTEMS_DEQUALIFY_DEPTHX
+#define RTEMS_DECONST( _type, _var ) \
+  RTEMS_DEQUALIFY_DEPTHX( *, _type, _var )
+#else /*RTEMS_DEQUALIFY_DEPTHX*/
 /**
  * @brief Removes the const qualifier from a type of a variable.
  *
@@ -236,6 +269,14 @@
 #define RTEMS_DECONST( _type, _var ) \
   ((_type)(uintptr_t)(const void *) ( _var ))
 
+#endif /*RTEMS_DEQUALIFY_DEPTHX*/
+#endif /*RTEMS_DECONST*/
+
+#ifndef RTEMS_DEVOLATILE
+#ifdef RTEMS_DEQUALIFY_DEPTHX
+#define RTEMS_DEVOLATILE( _type, _var ) \
+  RTEMS_DEQUALIFY_DEPTHX( *, _type, _var )
+#else /*RTEMS_DEQUALIFY_DEPTHX*/
 /**
  * @brief Removes the volatile qualifier from a type of a variable.
  *
@@ -245,6 +286,14 @@
 #define RTEMS_DEVOLATILE( _type, _var ) \
   ((_type)(uintptr_t)(volatile void *) ( _var ))
 
+#endif /*RTEMS_DEQUALIFY_DEPTHX*/
+#endif /*RTEMS_DEVOLATILE*/
+
+#ifndef RTEMS_DEQUALIFY
+#ifdef RTEMS_DEQUALIFY_DEPTHX
+#define RTEMS_DEQUALIFY( _type, _var ) \
+  RTEMS_DEQUALIFY_DEPTHX( *, _type, _var )
+#else /*RTEMS_DEQUALIFY_DEPTHX*/
 /**
  * @brief Removes the all qualifiers from a type of a variable.
  *
@@ -254,6 +303,9 @@
 #define RTEMS_DEQUALIFY( _type, _var ) \
   ((_type)(uintptr_t)(const volatile void *) ( _var ))
 
+#endif /*RTEMS_DEQUALIFY_DEPTHX*/
+#endif /*RTEMS_DEQUALIFY*/
+
 #ifndef ASM
   #ifdef RTEMS_DEPRECATED_TYPES
     typedef bool boolean;