diff mbox series

[Ada] Fix violation of No_Implicit_Loops restriction for enumeration type

Message ID 20210708135025.GA2465883@adacore.com
State New
Headers show
Series [Ada] Fix violation of No_Implicit_Loops restriction for enumeration type | expand

Commit Message

Pierre-Marie de Rodat July 8, 2021, 1:50 p.m. UTC 
The perfect hash function generated by the compiler to speed up the Value
attribute of an enumeration type contains an implicit loop and, therefore,
violates the No_Implicit_Loops restriction when it is active.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* exp_imgv.adb: Add with and use clause for Restrict and Rident.
	(Build_Enumeration_Image_Tables): Do not generate the hash function
	if the No_Implicit_Loops restriction is active.
diff mbox series

Patch

diff --git a/gcc/ada/exp_imgv.adb b/gcc/ada/exp_imgv.adb
--- a/gcc/ada/exp_imgv.adb
+++ b/gcc/ada/exp_imgv.adb
@@ -37,6 +37,8 @@  with Namet;          use Namet;
 with Nmake;          use Nmake;
 with Nlists;         use Nlists;
 with Opt;            use Opt;
+with Restrict;       use Restrict;
+with Rident;         use Rident;
 with Rtsfind;        use Rtsfind;
 with Sem_Aux;        use Sem_Aux;
 with Sem_Res;        use Sem_Res;
@@ -160,6 +162,8 @@  package body Exp_Imgv is
              Expression          => Make_Aggregate (Loc, Expressions => V)));
       end Append_Table_To;
 
+   --  Start of Build_Enumeration_Image_Tables
+
    begin
       --  Nothing to do for types other than a root enumeration type
 
@@ -247,7 +251,7 @@  package body Exp_Imgv is
       Append_Table_To (Act, Eind, Nlit, Ityp, Ind);
 
       --  If the number of literals is not greater than Threshold, then we are
-      --  done. Otherwise we compute a (perfect) hash function for use by the
+      --  done. Otherwise we generate a (perfect) hash function for use by the
       --  Value attribute.
 
       if Nlit > Threshold then
@@ -283,11 +287,12 @@  package body Exp_Imgv is
 
          --  If the unit where the type is declared is the main unit, and the
          --  number of literals is greater than Threshold_For_Size when we are
-         --  optimizing for size, and -gnatd_h is not specified, try to compute
-         --  the hash function.
+         --  optimizing for size, and the restriction No_Implicit_Loops is not
+         --  active, and -gnatd_h is not specified, generate the hash function.
 
          if In_Main_Unit
            and then (Optimize_Size = 0 or else Nlit > Threshold_For_Size)
+           and then not Restriction_Active (No_Implicit_Loops)
            and then not Debug_Flag_Underscore_H
          then
             declare