From: Robert Dewar Date: Wed, 26 Sep 2007 10:42:29 +0000 (+0200) Subject: checks.adb, [...]: Improve warnings for address overlays. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2642f9987ea72b416bce764ca3d95c19c9e77836;p=gcc.git checks.adb, [...]: Improve warnings for address overlays. 2007-09-26 Robert Dewar * checks.adb, gnat1drv.adb, sem_util.ads: Improve warnings for address overlays. * sem_ch13.ads, sem_ch13.adb: Improve warnings for address overlays (Analyze_Record_Representation_Clause): Suppress junk warning for missing component clause. (Analyze_Attribute_Definition_Clause, case Address): Apply the special tests for controlled type overlay to composites with controlled components. (Analyze_Record_Representation_Clause): Add reference for component name From-SVN: r128785 --- diff --git a/gcc/ada/checks.adb b/gcc/ada/checks.adb index 30a3f26e890..33696b0003c 100644 --- a/gcc/ada/checks.adb +++ b/gcc/ada/checks.adb @@ -543,6 +543,7 @@ package body Checks is Error_Msg_FE ("\?program execution may be erroneous (RM 13.3(27))", Aexp, E); + Set_Address_Warning_Posted (AC); end if; end Compile_Time_Bad_Alignment; @@ -626,6 +627,7 @@ package body Checks is Error_Msg_FE ("\?program execution may be erroneous", Aexp, E); Size_Warning_Output := True; + Set_Address_Warning_Posted (AC); end if; end if; end; diff --git a/gcc/ada/gnat1drv.adb b/gcc/ada/gnat1drv.adb index 7ab1d3687e1..743520ee799 100644 --- a/gcc/ada/gnat1drv.adb +++ b/gcc/ada/gnat1drv.adb @@ -442,6 +442,7 @@ begin if Compilation_Errors then Treepr.Tree_Dump; Sem_Ch13.Validate_Unchecked_Conversions; + Sem_Ch13.Validate_Address_Clauses; Errout.Output_Messages; Namet.Finalize; @@ -622,6 +623,7 @@ begin Write_Eol; Sem_Ch13.Validate_Unchecked_Conversions; + Sem_Ch13.Validate_Address_Clauses; Errout.Finalize (Last_Call => True); Errout.Output_Messages; Treepr.Tree_Dump; @@ -654,6 +656,7 @@ begin or else Targparm.VM_Target /= No_VM) then Sem_Ch13.Validate_Unchecked_Conversions; + Sem_Ch13.Validate_Address_Clauses; Errout.Finalize (Last_Call => True); Errout.Output_Messages; Write_ALI (Object => False); @@ -704,6 +707,11 @@ begin Sem_Ch13.Validate_Unchecked_Conversions; + -- Validate address clauses (again using alignment values annotated + -- by the backend where possible). + + Sem_Ch13.Validate_Address_Clauses; + -- Now we complete output of errors, rep info and the tree info. These -- are delayed till now, since it is perfectly possible for gigi to -- generate errors, modify the tree (in particular by setting flags diff --git a/gcc/ada/sem_ch13.adb b/gcc/ada/sem_ch13.adb index 838436d7811..a632d0dfc87 100644 --- a/gcc/ada/sem_ch13.adb +++ b/gcc/ada/sem_ch13.adb @@ -30,6 +30,7 @@ with Errout; use Errout; with Exp_Tss; use Exp_Tss; with Exp_Util; use Exp_Util; with Lib; use Lib; +with Lib.Xref; use Lib.Xref; with Namet; use Namet; with Nlists; use Nlists; with Nmake; use Nmake; @@ -88,11 +89,6 @@ package body Sem_Ch13 is function Address_Aliased_Entity (N : Node_Id) return Entity_Id; -- If expression N is of the form E'Address, return E - procedure Mark_Aliased_Address_As_Volatile (N : Node_Id); - -- This is used for processing of an address representation clause. If - -- the expression N is of the form of K'Address, then the entity that - -- is associated with K is marked as volatile. - procedure New_Stream_Subprogram (N : Node_Id; Ent : Entity_Id; @@ -138,6 +134,41 @@ package body Sem_Ch13 is Table_Increment => 200, Table_Name => "Unchecked_Conversions"); + ---------------------------------------- + -- Table for Validate_Address_Clauses -- + ---------------------------------------- + + -- If an address clause has the form + + -- for X'Address use Expr + + -- where Expr is of the form Y'Address or recursively is a reference + -- to a constant of either of these forms, and X and Y are entities of + -- objects, then if Y has a smaller alignment than X, that merits a + -- warning about possible bad alignment. The following table collects + -- address clauses of this kind. We put these in a table so that they + -- can be checked after the back end has completed annotation of the + -- alignments of objects, since we can catch more cases that way. + + type Address_Clause_Check_Record is record + N : Node_Id; + -- The address clause + + X : Entity_Id; + -- The entity of the object overlaying Y + + Y : Entity_Id; + -- The entity of the object being overlaid + end record; + + package Address_Clause_Checks is new Table.Table ( + Table_Component_Type => Address_Clause_Check_Record, + Table_Index_Type => Int, + Table_Low_Bound => 1, + Table_Initial => 20, + Table_Increment => 200, + Table_Name => "Address_Clause_Checks"); + ---------------------------- -- Address_Aliased_Entity -- ---------------------------- @@ -259,7 +290,7 @@ package body Sem_Ch13 is end loop; -- We need to sort the component clauses on the basis of the Position - -- values in the clause, so we can group clauses with the same Position + -- values in the clause, so we can group clauses with the same Position. -- together to determine the relevant machine scalar size. declare @@ -601,7 +632,6 @@ package body Sem_Ch13 is else Get_First_Interp (Expr, I, It); - while Present (It.Nam) loop if Has_Good_Profile (It.Nam) then Subp := It.Nam; @@ -720,11 +750,12 @@ package body Sem_Ch13 is ("address clause cannot be given " & "for overloaded subprogram", Nam); + return; end if; - -- For subprograms, all address clauses are permitted, - -- and we mark the subprogram as having a deferred freeze - -- so that Gigi will not elaborate it too soon. + -- For subprograms, all address clauses are permitted, and we + -- mark the subprogram as having a deferred freeze so that Gigi + -- will not elaborate it too soon. -- Above needs more comments, what is too soon about??? @@ -736,12 +767,15 @@ package body Sem_Ch13 is if Nkind (Parent (N)) = N_Task_Body then Error_Msg_N ("entry address must be specified in task spec", Nam); + return; end if; -- For entries, we require a constant address Check_Constant_Address_Clause (Expr, U_Ent); + -- Special checks for task types + if Is_Task_Type (Scope (U_Ent)) and then Comes_From_Source (Scope (U_Ent)) then @@ -751,6 +785,8 @@ package body Sem_Ch13 is ("\?only one task can be declared of this type", N); end if; + -- Entry address clauses are obsolescent + Check_Restriction (No_Obsolescent_Features, N); if Warn_On_Obsolescent_Feature then @@ -761,10 +797,12 @@ package body Sem_Ch13 is ("\use interrupt procedure instead?", N); end if; - -- Case of an address clause for a controlled object: - -- erroneous execution. + -- Case of an address clause for a controlled object which we + -- consider to be erroneous. - elsif Is_Controlled (Etype (U_Ent)) then + elsif Is_Controlled (Etype (U_Ent)) + or else Has_Controlled_Component (Etype (U_Ent)) + then Error_Msg_NE ("?controlled object& must not be overlaid", Nam, U_Ent); Error_Msg_N @@ -772,6 +810,7 @@ package body Sem_Ch13 is Insert_Action (Declaration_Node (U_Ent), Make_Raise_Program_Error (Loc, Reason => PE_Overlaid_Controlled_Object)); + return; -- Case of address clause for a (non-controlled) object @@ -781,8 +820,9 @@ package body Sem_Ch13 is Ekind (U_Ent) = E_Constant then declare - Expr : constant Node_Id := Expression (N); - Aent : constant Entity_Id := Address_Aliased_Entity (Expr); + Expr : constant Node_Id := Expression (N); + Aent : constant Entity_Id := Address_Aliased_Entity (Expr); + Ent_Y : constant Entity_Id := Find_Overlaid_Object (N); begin -- Exported variables cannot have an address clause, @@ -791,19 +831,22 @@ package body Sem_Ch13 is if Is_Exported (U_Ent) then Error_Msg_N ("cannot export object with address clause", Nam); + return; -- Overlaying controlled objects is erroneous elsif Present (Aent) - and then Is_Controlled (Etype (Aent)) + and then (Has_Controlled_Component (Etype (Aent)) + or else Is_Controlled (Etype (Aent))) then Error_Msg_N - ("?controlled object must not be overlaid", Expr); + ("?cannot overlay with controlled object", Expr); Error_Msg_N ("\?Program_Error will be raised at run time", Expr); Insert_Action (Declaration_Node (U_Ent), Make_Raise_Program_Error (Loc, Reason => PE_Overlaid_Controlled_Object)); + return; elsif Present (Aent) and then Ekind (U_Ent) = E_Constant @@ -815,6 +858,7 @@ package body Sem_Ch13 is Error_Msg_N ("address clause not allowed" & " for a renaming declaration (RM 13.1(6))", Nam); + return; -- Imported variables can have an address clause, but then -- the import is pretty meaningless except to suppress @@ -831,41 +875,13 @@ package body Sem_Ch13 is Note_Possible_Modification (Nam); - -- Here we are checking for explicit overlap of one - -- variable by another, and if we find this, then we - -- mark the overlapped variable as also being aliased. - - -- First case is where we have an explicit - - -- for J'Address use K'Address; + -- Here we are checking for explicit overlap of one variable + -- by another, and if we find this then mark the overlapped + -- variable as also being volatile to prevent unwanted + -- optimizations. - -- In this case, we mark K as volatile - - Mark_Aliased_Address_As_Volatile (Expr); - - -- Second case is where we have a constant whose - -- definition is of the form of an address as in: - - -- A : constant Address := K'Address; - -- ... - -- for B'Address use A; - - -- In this case we also mark K as volatile - - if Is_Entity_Name (Expr) then - declare - Ent : constant Entity_Id := Entity (Expr); - Decl : constant Node_Id := Declaration_Node (Ent); - - begin - if Ekind (Ent) = E_Constant - and then Nkind (Decl) = N_Object_Declaration - and then Present (Expression (Decl)) - then - Mark_Aliased_Address_As_Volatile - (Expression (Decl)); - end if; - end; + if Present (Ent_Y) then + Set_Treat_As_Volatile (Ent_Y); end if; -- Legality checks on the address clause for initialized @@ -900,6 +916,38 @@ package body Sem_Ch13 is Kill_Size_Check_Code (U_Ent); end; + -- If the address clause is of the form: + + -- for X'Address use Y'Address + + -- or + + -- Const : constant Address := Y'Address; + -- ... + -- for X'Address use Const; + + -- then we make an entry in the table for checking the size and + -- alignment of the overlaying variable. We defer this check + -- till after code generation to take full advantage of the + -- annotation done by the back end. This entry is only made if + -- we have not already posted a warning about size/alignment + -- (some warnings of this type are posted in Checks). + + if Address_Clause_Overlay_Warnings then + declare + Ent_X : Entity_Id := Empty; + Ent_Y : Entity_Id := Empty; + + begin + Ent_Y := Find_Overlaid_Object (N); + + if Present (Ent_Y) and then Is_Entity_Name (Name (N)) then + Ent_X := Entity (Name (N)); + Address_Clause_Checks.Append ((N, Ent_X, Ent_Y)); + end if; + end; + end if; + -- Not a valid entity for an address clause else @@ -2137,7 +2185,7 @@ package body Sem_Ch13 is end if; -- Clear any existing component clauses for the type (this happens with - -- derived types, where we are now overriding the original) + -- derived types, where we are now overriding the original). Comp := First_Component_Or_Discriminant (Rectype); while Present (Comp) loop @@ -2274,6 +2322,13 @@ package body Sem_Ch13 is ("component clause previously given#", CC); else + -- Make reference for field in record rep clause and set + -- appropriate entity field in the field identifier. + + Generate_Reference + (Comp, Component_Name (CC), Set_Ref => False); + Set_Entity (Component_Name (CC), Comp); + -- Update Fbit and Lbit to the actual bit number Fbit := Fbit + UI_From_Int (SSU) * Posit; @@ -2641,7 +2696,11 @@ package body Sem_Ch13 is then Comp := First_Component_Or_Discriminant (Rectype); while Present (Comp) loop - if No (Component_Clause (Comp)) then + if No (Component_Clause (Comp)) + and then (Is_Scalar_Type (Underlying_Type (Etype (Comp))) + or else Size_Known_At_Compile_Time + (Underlying_Type (Etype (Comp)))) + then Error_Msg_Sloc := Sloc (Comp); Error_Msg_NE ("?no component clause given for & declared #", @@ -3236,19 +3295,6 @@ package body Sem_Ch13 is end if; end Is_Operational_Item; - -------------------------------------- - -- Mark_Aliased_Address_As_Volatile -- - -------------------------------------- - - procedure Mark_Aliased_Address_As_Volatile (N : Node_Id) is - Ent : constant Entity_Id := Address_Aliased_Entity (N); - - begin - if Present (Ent) then - Set_Treat_As_Volatile (Ent); - end if; - end Mark_Aliased_Address_As_Volatile; - ------------------ -- Minimum_Size -- ------------------ @@ -3965,12 +4011,110 @@ package body Sem_Ch13 is and then Esize (T) < Standard_Integer_Size then Init_Esize (T, Standard_Integer_Size); - else Init_Esize (T, Sz); end if; end Set_Enum_Esize; + ------------------------------ + -- Validate_Address_Clauses -- + ------------------------------ + + procedure Validate_Address_Clauses is + begin + for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop + declare + ACCR : Address_Clause_Check_Record + renames Address_Clause_Checks.Table (J); + + X_Alignment : Uint; + Y_Alignment : Uint; + + X_Size : Uint; + Y_Size : Uint; + + begin + -- Skip processing of this entry if warning already posted + + if not Address_Warning_Posted (ACCR.N) then + + -- Get alignments. Really we should always have the alignment + -- of the objects properly back annotated, but right now the + -- back end fails to back annotate for address clauses??? + + if Known_Alignment (ACCR.X) then + X_Alignment := Alignment (ACCR.X); + else + X_Alignment := Alignment (Etype (ACCR.X)); + end if; + + if Known_Alignment (ACCR.Y) then + Y_Alignment := Alignment (ACCR.Y); + else + Y_Alignment := Alignment (Etype (ACCR.Y)); + end if; + + -- Similarly obtain sizes + + if Known_Esize (ACCR.X) then + X_Size := Esize (ACCR.X); + else + X_Size := Esize (Etype (ACCR.X)); + end if; + + if Known_Esize (ACCR.Y) then + Y_Size := Esize (ACCR.Y); + else + Y_Size := Esize (Etype (ACCR.Y)); + end if; + + -- Check for large object overlaying smaller one + + if Y_Size > Uint_0 + and then X_Size > Uint_0 + and then X_Size > Y_Size + then + Error_Msg_N + ("?size for overlaid object is too small", ACCR.N); + Error_Msg_Uint_1 := X_Size; + Error_Msg_NE + ("\?size of & is ^", ACCR.N, ACCR.X); + Error_Msg_Uint_1 := Y_Size; + Error_Msg_NE + ("\?size of & is ^", ACCR.N, ACCR.Y); + + -- Check for inadequate alignment. Again the defensive check + -- on Y_Alignment should not be needed, but because of the + -- failure in back end annotation, we can have an alignment + -- of 0 here??? + + -- Note: we do not check alignments if we gave a size + -- warning, since it would likely be redundant. + + elsif Y_Alignment /= Uint_0 + and then Y_Alignment < X_Alignment + then + Error_Msg_NE + ("?specified address for& may be inconsistent " + & "with alignment", + ACCR.N, ACCR.X); + Error_Msg_N + ("\?program execution may be erroneous (RM 13.3(27))", + ACCR.N); + Error_Msg_Uint_1 := X_Alignment; + Error_Msg_NE + ("\?alignment of & is ^", + ACCR.N, ACCR.X); + Error_Msg_Uint_1 := Y_Alignment; + Error_Msg_NE + ("\?alignment of & is ^", + ACCR.N, ACCR.Y); + end if; + end if; + end; + end loop; + end Validate_Address_Clauses; + ----------------------------------- -- Validate_Unchecked_Conversion -- ----------------------------------- diff --git a/gcc/ada/sem_ch13.ads b/gcc/ada/sem_ch13.ads index c34981f0427..3c5681c7bf2 100644 --- a/gcc/ada/sem_ch13.ads +++ b/gcc/ada/sem_ch13.ads @@ -161,4 +161,10 @@ package Sem_Ch13 is -- The reason it is called that late is to take advantage of any -- back-annotation of size and alignment performed by the backend. + procedure Validate_Address_Clauses; + -- This is called after the back end has been called (and thus after the + -- alignments of objects have been back annotated). It goes through the + -- table of saved address clauses checking for suspicious alignments and + -- if necessary issuing warnings. + end Sem_Ch13; diff --git a/gcc/ada/sem_util.ads b/gcc/ada/sem_util.ads index b2c1b11d2a8..c0ce298befa 100644 --- a/gcc/ada/sem_util.ads +++ b/gcc/ada/sem_util.ads @@ -292,6 +292,13 @@ package Sem_Util is -- denotes when analyzed. Subsequent uses of this id on a different -- type denote the discriminant at the same position in this new type. + function Find_Overlaid_Object (N : Node_Id) return Entity_Id; + -- The node N should be an address representation clause. This function + -- checks if the target expression is the address of some stand alone + -- object (variable or constant), and if so, returns its entity. If N is + -- not an address representation clause, or if it is not possible to + -- determine that the address is of this form, then Empty is returned. + function Find_Overridden_Synchronized_Primitive (Def_Id : Entity_Id; First_Hom : Entity_Id; @@ -304,6 +311,11 @@ package Sem_Util is -- declared inside the scope of the synchronized type or after. Return -- the overridden entity or Empty. + function Find_Static_Alternative (N : Node_Id) return Node_Id; + -- N is a case statement whose expression is a compile-time value. + -- Determine the alternative chosen, so that the code of non-selected + -- alternatives, and the warnings that may apply to them, are removed. + function First_Actual (Node : Node_Id) return Node_Id; -- Node is an N_Function_Call or N_Procedure_Call_Statement node. The -- result returned is the first actual parameter in declaration order @@ -321,11 +333,6 @@ package Sem_Util is -- name in upper case. An ASCII.NUL is appended as the last character. -- The names in the string are generated by Namet.Get_Decoded_Name_String. - function Find_Static_Alternative (N : Node_Id) return Node_Id; - -- N is a case statement whose expression is a compile-time value. - -- Determine the alternative chosen, so that the code of non-selected - -- alternatives, and the warnings that may apply to them, are removed. - procedure Gather_Components (Typ : Entity_Id; Comp_List : Node_Id;