[include] Add macro DISABLE_COPY_AND_ASSIGN

We have many classes that copy cotr and assignment operator are deleted
in different projects, gcc, gdb and gold.  So this patch adds a macro
to do this, and replace these existing mechanical code with macro
DISABLE_COPY_AND_ASSIGN.

The patch was posted in gdb-patches,
https://sourceware.org/ml/gdb-patches/2017-07/msg00254.html but we
think it is better to put this macro in include/ansidecl.h so that
other projects can use it too.

include:

2017-09-15  Yao Qi  <yao.qi@linaro.org>
	    Pedro Alves  <palves@redhat.com>

	* ansidecl.h (DISABLE_COPY_AND_ASSIGN): New macro.

Co-Authored-By: Pedro Alves <palves@redhat.com>
From-SVN: r252823

diff --git a/include/ChangeLog b/include/ChangeLog
index 4703588..0221586 100644 (file)
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,8 @@
+2017-09-15  Yao Qi  <yao.qi@linaro.org>
+           Pedro Alves  <palves@redhat.com>
+
+       * ansidecl.h (DISABLE_COPY_AND_ASSIGN): New macro.
+
 2017-09-12  Jiong Wang  <jiong.wang@arm.com>
 
        * dwarf2.def (DW_CFA_AARCH64_negate_ra_state): New DW_CFA_DUP.

diff --git a/include/ansidecl.h b/include/ansidecl.h
index ab3b895..450ce35 100644 (file)
--- a/include/ansidecl.h
+++ b/include/ansidecl.h
@@ -360,6 +360,32 @@ So instead we use the macro below and test it against specific values.  */
 # define FINAL
 #endif
 
+/* A macro to disable the copy constructor and assignment operator.
+   When building with C++11 and above, the methods are explicitly
+   deleted, causing a compile-time error if something tries to copy.
+   For C++03, this just declares the methods, causing a link-time
+   error if the methods end up called (assuming you don't
+   define them).  For C++03, for best results, place the macro
+   under the private: access specifier, like this,
+
+   class name_lookup
+   {
+     private:
+       DISABLE_COPY_AND_ASSIGN (name_lookup);
+   };
+
+   so that most attempts at copy are caught at compile-time.  */
+
+#if __cplusplus >= 201103
+#define DISABLE_COPY_AND_ASSIGN(TYPE)          \
+  TYPE (const TYPE&) = delete;                 \
+  void operator= (const TYPE &) = delete
+  #else
+#define DISABLE_COPY_AND_ASSIGN(TYPE)          \
+  TYPE (const TYPE&);                          \
+  void operator= (const TYPE &)
+#endif /* __cplusplus >= 201103 */
+
 #ifdef __cplusplus
 }
 #endif