[COMMITTED] ada: Introduce -gnateH switch to force reverse Bit_Order threshold to 64
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Commit Message
From: Eric Botcazou <ebotcazou@adacore.com>
This can be helpful for legacy code that still makes use of an original
reverse Bit_Order clause, i.e. without a Scalar_Storage_Order clause.
gcc/ada/
* doc/gnat_ugn/building_executable_programs_with_gnat.rst (Compiler
Switches): Document -gnateH.
* opt.ads (Reverse_Bit_Order_Threshold): New variable.
* sem_ch13.adb (Adjust_Record_For_Reverse_Bit_Order): Use its value
if it is nonnegative instead of System_Max_Integer_Size.
* switch-c.adb (Scan_Front_End_Switches): Deal with -gnateH.
* usage.adb (Usage): Print -gnateH.
* gnat_ugn.texi: Regenerate.
Tested on x86_64-pc-linux-gnu, committed on master.
---
.../building_executable_programs_with_gnat.rst | 8 ++++++++
gcc/ada/gnat_ugn.texi | 14 +++++++++++++-
gcc/ada/opt.ads | 5 +++++
gcc/ada/sem_ch13.adb | 4 +++-
gcc/ada/switch-c.adb | 6 ++++++
gcc/ada/usage.adb | 5 +++++
6 files changed, 40 insertions(+), 2 deletions(-)
@@ -1612,6 +1612,14 @@ Alphabetical List of All Switches
Save result of preprocessing in a text file.
+.. index:: -gnateH (gcc)
+
+:switch:`-gnateH`
+ Set the threshold from which the RM 13.5.1(13.3/2) clause applies to 64.
+ This is useful only on 64-bit plaforms where this threshold is 128, but
+ used to be 64 in earlier versions of the compiler.
+
+
.. index:: -gnatei (gcc)
:switch:`-gnatei{nnn}`
@@ -19,7 +19,7 @@
@copying
@quotation
-GNAT User's Guide for Native Platforms , Jun 01, 2023
+GNAT User's Guide for Native Platforms , Jun 16, 2023
AdaCore
@@ -9075,6 +9075,18 @@ information.
Save result of preprocessing in a text file.
@end table
+@geindex -gnateH (gcc)
+
+
+@table @asis
+
+@item @code{-gnateH}
+
+Set the threshold from which the RM 13.5.1(13.3/2) clause applies to 64.
+This is useful only on 64-bit plaforms where this threshold is 128, but
+used to be 64 in earlier versions of the compiler.
+@end table
+
@geindex -gnatei (gcc)
@@ -1342,6 +1342,11 @@ package Opt is
-- GNATPREP
-- Set to True if -C switch used.
+ Reverse_Bit_Order_Threshold : Int := -1;
+ -- GNAT
+ -- Set to the threshold from which the RM 13.5.1(13.3/2) clause applies,
+ -- or -1 if the size of the largest machine scalar is to be used.
+
RTS_Lib_Path_Name : String_Ptr := null;
RTS_Src_Path_Name : String_Ptr := null;
-- GNAT
@@ -426,7 +426,9 @@ package body Sem_Ch13 is
procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id) is
Max_Machine_Scalar_Size : constant Uint :=
- UI_From_Int (System_Max_Integer_Size);
+ UI_From_Int (if Reverse_Bit_Order_Threshold >= 0
+ then Reverse_Bit_Order_Threshold
+ else System_Max_Integer_Size);
-- We use this as the maximum machine scalar size
SSU : constant Uint := UI_From_Int (System_Storage_Unit);
@@ -635,6 +635,12 @@ package body Switch.C is
Generate_Processed_File := True;
Ptr := Ptr + 1;
+ -- -gnateH (set reverse Bit_Order threshold to 64)
+
+ when 'H' =>
+ Reverse_Bit_Order_Threshold := 64;
+ Ptr := Ptr + 1;
+
-- -gnatei (max number of instantiations)
when 'i' =>
@@ -199,6 +199,11 @@ begin
Write_Switch_Char ("eG");
Write_Line ("Generate preprocessed source");
+ -- Line for -gnateH switch
+
+ Write_Switch_Char ("eH");
+ Write_Line ("Set reverse Bit_Order threshold to 64");
+
-- Line for -gnatei switch
Write_Switch_Char ("einn");