gnat_project_manager.rst, [...]: Update doc.

        * gnat_ugn/gnat_project_manager.rst,
        gnat_ugn/building_executable_programs_with_gnat.rst,
        gnat_ugn/gnat_and_program_execution.rst,
        gnat_ugn/the_gnat_compilation_model.rst,
        gnat_rm/implementation_defined_pragmas.rst,
        gnat_rm/standard_and_implementation_defined_restrictions.rst,
        gnat_ugn.texi, gnat_rm.texi: Update doc.

From-SVN: r230538

gcc/ada/ChangeLog

+2015-11-18  Arnaud Charlet  <charlet@adacore.com>
+
+	* gnat_ugn/gnat_project_manager.rst,
+	gnat_ugn/building_executable_programs_with_gnat.rst,
+	gnat_ugn/gnat_and_program_execution.rst,
+	gnat_ugn/the_gnat_compilation_model.rst,
+	gnat_rm/implementation_defined_pragmas.rst,
+	gnat_rm/standard_and_implementation_defined_restrictions.rst,
+	gnat_ugn.texi, gnat_rm.texi: Update doc.
+
 2015-11-18  Hristian Kirtchev  <kirtchev@adacore.com>
 
 	* contracts.adb (Add_Contract_Item): Chain pragmas Attach_Handler

gcc/ada/doc/gnat_rm/standard_and_implementation_defined_restrictions.rst

@@ -772,7 +772,7 @@ Pure_Barriers
 [GNAT] This restriction ensures at compile time that protected entry
 barriers are restricted to:
 
-* simple boolean variables defined in the private part of the
+* simple variables defined in the private part of the
   protected type/object,
 * constant declarations,
 * named numbers,

gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst

@@ -1306,6 +1306,17 @@ Alphabetical List of All Switches
   :ref:`Optimization_and_Strict_Aliasing` for details.
 
 
+.. index:: -fno-strict-overflow  (gcc)
+
+:samp:`-fno-strict-overflow`
+  Causes the compiler to avoid assumptions regarding the rules of signed
+  integer overflow. These rules specify that signed integer overflow will
+  result in a Constraint_Error exception at run time and are enforced in
+  default mode by the compiler, so this switch should not be necessary in
+  normal operating mode. It might be useful in conjunction with *-gnato0*
+  for very peculiar cases of low-level programming.
+
+
 .. index:: -fstack-check  (gcc)
 
 :samp:`-fstack-check`
@@ -1548,6 +1559,17 @@ Alphabetical List of All Switches
   `Check_Float_Overflow` in GNAT RM.
 
 
+.. index:: -gnateg  (gcc)
+
+:samp:`-gnateg`
+:samp:`-gnatceg`
+
+  The `-gnatc` switch must always be specified before this switch, e.g.
+  `-gnatceg`. Generate a C header from the Ada input file. See
+  :ref:`Generating_C_Headers_for_Ada_Specifications` for more
+  information.
+
+
 .. index:: -gnateG  (gcc)
 
 :samp:`-gnateG`

gcc/ada/doc/gnat_ugn/gnat_and_program_execution.rst

@@ -2999,9 +2999,9 @@ exception raised because of the intermediate overflow (and we really
 would prefer this precondition to be considered True at run time).
 
 
-.. _Overflow_Checking_Modes_in_GNAT:
+.. _Management_of_Overflows_in_GNAT:
 
-Overflow Checking Modes in GNAT
+Management of Overflows in GNAT
 -------------------------------
 
 To deal with the portability issue, and with the problem of
@@ -3202,7 +3202,7 @@ The default mode for overflow checks is
       General => Strict
 
 which causes all computations both inside and outside assertions to use
-the base type. In addition overflow checks are suppressed.
+the base type.
 
 This retains compatibility with previous versions of
 GNAT which suppressed overflow checks by default and always
@@ -3220,8 +3220,6 @@ is equivalent to
 
 which causes overflow checking of all intermediate overflows
 both inside and outside assertions against the base type.
-This provides compatibility
-with this switch as implemented in previous versions of GNAT.
 
 The pragma `Suppress (Overflow_Check)` disables overflow
 checking, but it has no effect on the method used for computing

gcc/ada/doc/gnat_ugn/gnat_project_manager.rst

@@ -2390,7 +2390,7 @@ building. The syntax looks like
         for External ("BUILD") use "PRODUCTION";
 
         package Builder is
-           for Switches ("Ada") use ("-q");
+           for Global_Compilation_Switches ("Ada") use ("-g");
         end Builder;
      end Agg;
 

gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst

@@ -4439,7 +4439,7 @@ easier to interface with other languages than previous versions of Ada.
 
 .. _Running_the_binding_generator:
 
-Running the binding generator
+Running the Binding Generator
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The binding generator is part of the *gcc* compiler and can be
@@ -4534,7 +4534,7 @@ and then generate Ada bindings from this file:
 
 .. _Generating_bindings_for_C++_headers:
 
-Generating bindings for C++ headers
+Generating Bindings for C++ Headers
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Generating bindings for C++ headers is done using the same options, always
@@ -4662,6 +4662,91 @@ Switches
 :samp:`-C`
   Extract comments from headers and generate Ada comments in the Ada spec files.
 
+.. _Generating_C_Headers_for_Ada_Specifications:
+
+Generating C Headers for Ada Specifications
+-------------------------------------------
+
+.. index:: Binding generation (for Ada specs)
+.. index:: C headers (binding generation)
+
+GNAT includes a C header generator for Ada specifications which supports
+Ada types that have a direct mapping to C types. This includes in particular
+support for:
+
+* Scalar types
+* Constrained arrays
+* Records (untagged)
+* Composition of the above types
+* Constant declarations
+* Object declarations
+* Subprogram declarations
+
+Running the C Header Generator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The C header generator is part of the GNAT compiler and can be invoked via
+the *-gnatceg* combination of switches, which will generate a :file:`.h`
+file corresponding to the given input file (Ada spec or body). Note that
+only spec files are processed in any case, so giving a spec or a body file
+as input is equivalent. For example:
+
+.. code-block:: sh
+
+   $ gcc -c -gnatceg pack1.ads
+
+will generate a self-contained file called :file:`pack1.h` including
+common definitions from the Ada Standard package, followed by the
+definitions included in :file:`pack1.ads`, as well as all the other units
+withed by this file.
+
+For instance, given the following Ada files:
+
+.. code-block:: ada
+
+   package Pack2 is
+      type Int is range 1 .. 10;
+   end Pack2;
+
+.. code-block:: ada
+
+   with Pack2;
+
+   package Pack1 is
+      type Rec is record
+         Field1, Field2 : Pack2.Int;
+      end record;
+
+      Global : Rec := (1, 2);
+
+      procedure Proc1 (R : Rec);
+      procedure Proc2 (R : in out Rec);
+   end Pack1;
+
+The above `gcc` command will generate the following :file:`pack1.h` file:
+
+.. code-block:: c
+
+   /* Standard definitions skipped */
+   #ifndef PACK2_ADS
+   #define PACK2_ADS
+   typedef short_short_integer pack2__TintB;
+   typedef pack2__TintB pack2__int;
+   #endif /* PACK2_ADS */
+
+   #ifndef PACK1_ADS
+   #define PACK1_ADS
+   typedef struct _pack1__rec {
+     pack2__int field1;
+     pack2__int field2;
+   } pack1__rec;
+   extern pack1__rec pack1__global;
+   extern void pack1__proc1(const pack1__rec r);
+   extern void pack1__proc2(pack1__rec *r);
+   #endif /* PACK1_ADS */
+
+You can then `include` :file:`pack1.h` from a C source file and use the types,
+call subprograms, reference objects, and constants.
 
 .. _GNAT_and_Other_Compilation_Models: