[Ada] Export the Ada version through the C interface

2019-12-16  Eric Botcazou  <ebotcazou@adacore.com>

gcc/ada/

	* fe.h (Ada_Version_Type): New typedef.
	(Ada_Version): Declare.
	* opt.ads (Ada_Version_Type): Add Convention C and WARNING line.
	(Ada_Version): Add WARNING line.
	(Exception_Mechanism_Type): Likewise.

From-SVN: r279426

gcc/ada/ChangeLog

+2019-12-16  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* fe.h (Ada_Version_Type): New typedef.
+	(Ada_Version): Declare.
+	* opt.ads (Ada_Version_Type): Add Convention C and WARNING line.
+	(Ada_Version): Add WARNING line.
+	(Exception_Mechanism_Type): Likewise.
+
 2019-12-16  Gary Dismukes  <dismukes@adacore.com>
 
 	* checks.adb, sem_util.adb: Minor reformatting and U.S. spelling

gcc/ada/fe.h

@@ -36,7 +36,7 @@
 
    "WARNING: There is a matching C declaration of this <entity_kind> in fe.h"
 
-   where <entity_kind> is either "subprogram" or "variable".
+   where <entity_kind> is either "subprogram" or "variable" or "type".
 
    WARNING: functions taking String_Pointer parameters must abide by the rule
    documented alongside the definition of String_Pointer in types.h.  */
@@ -187,6 +187,7 @@ extern Boolean In_Extended_Main_Code_Unit	(Entity_Id);
 
 /* opt: */
 
+#define Ada_Version			opt__ada_version
 #define Back_End_Inlining		opt__back_end_inlining
 #define Debug_Generated_Code		opt__debug_generated_code
 #define Exception_Extra_Info		opt__exception_extra_info
@@ -199,9 +200,14 @@ extern Boolean In_Extended_Main_Code_Unit	(Entity_Id);
 #define Suppress_Checks			opt__suppress_checks
 
 typedef enum {
+  Ada_83, Ada_95, Ada_2005, Ada_2012, Ada_2020
+} Ada_Version_Type;
+
+typedef enum {
   Front_End_SJLJ, Back_End_ZCX, Back_End_SJLJ
 } Exception_Mechanism_Type;
 
+extern Ada_Version_Type Ada_Version;
 extern Boolean Back_End_Inlining;
 extern Boolean Debug_Generated_Code;
 extern Boolean Exception_Extra_Info;

gcc/ada/opt.ads

@@ -124,11 +124,14 @@ package Opt is
 
    type Ada_Version_Type is (Ada_83, Ada_95, Ada_2005, Ada_2012, Ada_2020);
    pragma Ordered (Ada_Version_Type);
+   pragma Convention (C, Ada_Version_Type);
    --  Versions of Ada for Ada_Version below. Note that these are ordered,
    --  so that tests like Ada_Version >= Ada_95 are legitimate and useful.
    --  Think twice before using "="; Ada_Version >= Ada_2012 is more likely
    --  what you want, because it will apply to future versions of the language.
 
+   --  WARNING: There is a matching C declaration of this type in fe.h
+
    Ada_Version_Default : constant Ada_Version_Type := Ada_2012;
    pragma Warnings (Off, Ada_Version_Default);
    --  GNAT
@@ -141,6 +144,8 @@ package Opt is
    --  compiler switches, or implicitly (to Ada_Version_Runtime) when a
    --  predefined or internal file is compiled.
 
+   --  WARNING: There is a matching C declaration of this variable in fe.h
+
    Ada_Version_Pragma : Node_Id := Empty;
    --  Reflects the Ada_xxx pragma that resulted in setting Ada_Version. Used
    --  to specialize error messages complaining about the Ada version in use.
@@ -629,9 +634,10 @@ package Opt is
       --  Similar to Back_End_ZCX with respect to the front-end processing
       --  of regular and AT-END handlers. A setjmp/longjmp scheme is used to
       --  propagate and setup handler contexts on regular execution paths.
-
    pragma Convention (C, Exception_Mechanism_Type);
 
+   --  WARNING: There is a matching C declaration of this type in fe.h
+
    Exception_Mechanism : Exception_Mechanism_Type := Front_End_SJLJ;
    --  GNAT
    --  Set to the appropriate value depending on the flags in system.ads