This fixes an assertion failure in gigi triggered by an order-of-elaboration issue for the type of a parameter of a subprogram which is both the renaming of another subprogram and marked Inline. In this case the compiler was using expansion (aka front-end inlining) but this doesn't always play nice with the freezing model used for generics so the patch makes it use back-end inlining.
The following package must compile quietly with -O -gnatn: with F; with G; package P is function Uid_Image (Uid : Integer) return String; package Inner is type Arr is array (Positive range <>) of Integer; function Image is new F (Integer, Positive, Arr, Uid_Image); end Inner; package Value_Set is new G (Integer); function Uid_Image (Uid : Integer) return String renames Value_Set.Uid_Image; pragma Inline (Uid_Image); end P; generic type Item_T is limited private; type Index_T is (<>); type Array_T is array (Index_T range <>) of Item_T; with function Image (Item : Item_T) return String; function F (A : Array_T) return String; with Ada.Strings.Unbounded; function F (A : Array_T) return String is Result : Ada.Strings.Unbounded.Unbounded_String; begin for I in A'Range loop Ada.Strings.Unbounded.Append (Result, Image (A (I))); end loop; return Ada.Strings.Unbounded.To_String (Result); end; generic type T is range <>; package G is function Uid_Image (Uid : T) return String; end G; package body G is function Uid_Image (Uid : T) return String is begin return T'Image (Uid); end; end G; Tested on x86_64-pc-linux-gnu, committed on trunk 2015-02-20 Eric Botcazou <ebotca...@adacore.com> * inline.adb (Expand_Inlined_Call): Skip again calls to subprogram renamings. * exp_ch6.adb (Expand_Call): Use back-end inlining instead of expansion for simple subprogram renamings.
Index: inline.adb =================================================================== --- inline.adb (revision 220841) +++ inline.adb (working copy) @@ -2694,12 +2694,11 @@ return; -- Skip inlining if this is not a true inlining since the attribute - -- Body_To_Inline is also set for renamings (see sinfo.ads) + -- Body_To_Inline is also set for renamings (see sinfo.ads). For a + -- true inlining, Orig_Bod has code rather than being an entity. elsif Nkind (Orig_Bod) in N_Entity then - if not Has_Pragma_Inline (Subp) then - return; - end if; + return; -- Skip inlining if the function returns an unconstrained type using -- an extended return statement since this part of the new inlining Index: exp_ch6.adb =================================================================== --- exp_ch6.adb (revision 220843) +++ exp_ch6.adb (working copy) @@ -3778,12 +3778,17 @@ or else Nkind (Unit_Declaration_Node (Subp)) /= N_Subprogram_Declaration or else No (Body_To_Inline (Unit_Declaration_Node (Subp))) + or else Nkind (Body_To_Inline (Unit_Declaration_Node (Subp))) in + N_Entity then Add_Inlined_Body (Subp, Call_Node); -- Front end expansion of simple functions returning unconstrained - -- types (see Check_And_Split_Unconstrained_Function) and simple - -- renamings inlined by the front end (see Build_Renamed_Body). + -- types (see Check_And_Split_Unconstrained_Function). Note that the + -- case of a simple renaming (Body_To_Inline in N_Entity above, see + -- also Build_Renamed_Body) cannot be expanded here because this may + -- give rise to order-of-elaboration issues for the types of the + -- parameters of the subprogram, if any. else Expand_Inlined_Call (Call_Node, Subp, Orig_Subp);