diff options
Diffstat (limited to 'gcc/ada/exp_prag.adb')
| -rw-r--r-- | gcc/ada/exp_prag.adb | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/gcc/ada/exp_prag.adb b/gcc/ada/exp_prag.adb index 469cb83..e7b16a9 100644 --- a/gcc/ada/exp_prag.adb +++ b/gcc/ada/exp_prag.adb @@ -39,6 +39,7 @@ with Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sem; use Sem; +with Sem_Ch8; use Sem_Ch8; with Sem_Res; use Sem_Res; with Sem_Util; use Sem_Util; with Sinfo; use Sinfo; @@ -68,6 +69,7 @@ package body Exp_Prag is procedure Expand_Pragma_Import_Export_Exception (N : Node_Id); procedure Expand_Pragma_Inspection_Point (N : Node_Id); procedure Expand_Pragma_Interrupt_Priority (N : Node_Id); + procedure Expand_Pragma_Loop_Assertion (N : Node_Id); procedure Expand_Pragma_Psect_Object (N : Node_Id); procedure Expand_Pragma_Relative_Deadline (N : Node_Id); @@ -189,6 +191,9 @@ package body Exp_Prag is when Pragma_Interrupt_Priority => Expand_Pragma_Interrupt_Priority (N); + when Pragma_Loop_Assertion => + Expand_Pragma_Loop_Assertion (N); + when Pragma_Psect_Object => Expand_Pragma_Psect_Object (N); @@ -790,6 +795,348 @@ package body Exp_Prag is end if; end Expand_Pragma_Interrupt_Priority; + ---------------------------------- + -- Expand_Pragma_Loop_Assertion -- + ---------------------------------- + + -- Pragma Loop_Assertion is expanded in the following manner: + + -- Original code + + -- for | while ... loop + -- <preceding source statements> + -- pragma Loop_Assertion + -- (Invariant => Invar_Expr, + -- Increases => Incr_Expr, + -- Decreases => Decr_Expr); + -- <succeeding source statements> + -- end loop; + + -- Expanded code + + -- Curr_1 : <type of Incr_Expr>; + -- Curr_2 : <type of Decr_Expr>; + -- Old_1 : <type of Incr_Expr>; + -- Old_2 : <type of Decr_Expr>; + -- Flag : Boolean := False; + -- + -- for | while ... loop + -- <preceding source statements> + -- + -- pragma Assert (<Invar_Expr>); + -- + -- if Flag then + -- Old_1 := Curr_1; + -- Old_2 := Curr_2; + -- end if; + -- + -- Curr_1 := <Incr_Expr>; + -- Curr_2 := <Decr_Expr>; + -- + -- if Flag then + -- if Curr_1 /= Old_1 then + -- pragma Assert (Curr_1 > Old_1); + -- else + -- pragma Assert (Curr_2 < Old_2); + -- end if; + -- else + -- Flag := True; + -- end if; + -- + -- <succeeding source statements> + -- end loop; + + procedure Expand_Pragma_Loop_Assertion (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Curr_Assign : List_Id := No_List; + Flag_Id : Entity_Id := Empty; + If_Stmt : Node_Id := Empty; + Loop_Scop : Entity_Id; + Loop_Stmt : Node_Id; + Old_Assign : List_Id := No_List; + + procedure Process_Increase_Decrease (Arg : Node_Id; Is_Last : Boolean); + -- Process a single increases/decreases expression. Flag Is_Last should + -- be set when the expression is the last argument to be processed. + + ------------------------------- + -- Process_Increase_Decrease -- + ------------------------------- + + procedure Process_Increase_Decrease (Arg : Node_Id; Is_Last : Boolean) is + function Make_Op + (Loc : Source_Ptr; + Curr_Val : Node_Id; + Old_Val : Node_Id) return Node_Id; + -- Generate a comparison between Curr_Val and Old_Val depending on + -- the argument name (Increases / Decreases). + + ------------- + -- Make_Op -- + ------------- + + function Make_Op + (Loc : Source_Ptr; + Curr_Val : Node_Id; + Old_Val : Node_Id) return Node_Id + is + begin + if Chars (Arg) = Name_Increases then + return + Make_Op_Gt (Loc, + Left_Opnd => Curr_Val, + Right_Opnd => Old_Val); + else + return + Make_Op_Lt (Loc, + Left_Opnd => Curr_Val, + Right_Opnd => Old_Val); + end if; + end Make_Op; + + -- Local variables + + Expr : constant Node_Id := Expression (Arg); + Loop_Loc : constant Source_Ptr := Sloc (Loop_Stmt); + Cond : Node_Id; + Curr_Id : Entity_Id; + Old_Id : Entity_Id; + Prag : Node_Id; + + -- Start of processing for Process_Increase_Decrease + + begin + -- All temporaries generated in this routine must be inserted before + -- the related loop statement. Ensure that the proper scope is on the + -- stack when analyzing the temporaries. + + Push_Scope (Scope (Loop_Scop)); + + -- Step 1: Create the declaration of the flag which controls the + -- behavior of the assertion on the first iteration of the loop. + + if No (Flag_Id) then + + -- Generate: + -- Flag : Boolean := False; + + Flag_Id := Make_Temporary (Loop_Loc, 'F'); + + Insert_Action (Loop_Stmt, + Make_Object_Declaration (Loop_Loc, + Defining_Identifier => Flag_Id, + Object_Definition => + New_Reference_To (Standard_Boolean, Loop_Loc), + Expression => + New_Reference_To (Standard_False, Loop_Loc))); + end if; + + -- Step 2: Create the temporaries which store the old and current + -- values of the associated expression. + + -- Generate: + -- Curr : <type of Expr>; + + Curr_Id := Make_Temporary (Loc, 'C'); + + Insert_Action (Loop_Stmt, + Make_Object_Declaration (Loop_Loc, + Defining_Identifier => Curr_Id, + Object_Definition => + New_Reference_To (Etype (Expr), Loop_Loc))); + + -- Generate: + -- Old : <type of Expr>; + + Old_Id := Make_Temporary (Loc, 'P'); + + Insert_Action (Loop_Stmt, + Make_Object_Declaration (Loop_Loc, + Defining_Identifier => Old_Id, + Object_Definition => + New_Reference_To (Etype (Expr), Loop_Loc))); + + -- Restore the original scope after all temporaries have been + -- analyzed. + + Pop_Scope; + + -- Step 3: Store the value of the expression from the previous + -- iteration. + + if No (Old_Assign) then + Old_Assign := New_List; + end if; + + -- Generate: + -- Old := Curr; + + Append_To (Old_Assign, + Make_Assignment_Statement (Loc, + Name => New_Reference_To (Old_Id, Loc), + Expression => New_Reference_To (Curr_Id, Loc))); + + -- Step 4: Store the current value of the expression + + if No (Curr_Assign) then + Curr_Assign := New_List; + end if; + + -- Generate: + -- Curr := <Expr>; + + Append_To (Curr_Assign, + Make_Assignment_Statement (Loc, + Name => New_Reference_To (Curr_Id, Loc), + Expression => Relocate_Node (Expr))); + + -- Step 5: Create the corresponding assertion to verify the change of + -- value. + + -- Generate: + -- pragma Assert (Curr <|> Old); + + Prag := + Make_Pragma (Loc, + Chars => Name_Assert, + Pragma_Argument_Associations => New_List ( + Make_Pragma_Argument_Association (Loc, + Expression => + Make_Op (Loc, + Curr_Val => New_Reference_To (Curr_Id, Loc), + Old_Val => New_Reference_To (Old_Id, Loc))))); + + -- Generate: + -- if Curr /= Old then + -- <Prag>; + + Cond := + Make_Op_Ne (Loc, + Left_Opnd => New_Reference_To (Curr_Id, Loc), + Right_Opnd => New_Reference_To (Old_Id, Loc)); + + if No (If_Stmt) then + If_Stmt := + Make_If_Statement (Loc, + Condition => Cond, + Then_Statements => New_List (Prag)); + + -- Generate: + -- else + -- <Prag>; + -- end if; + + elsif Is_Last then + Set_Else_Statements (If_Stmt, New_List (Prag)); + + -- Generate: + -- elsif Curr /= Old then + -- <Prag>; + + else + if Elsif_Parts (If_Stmt) = No_List then + Set_Elsif_Parts (If_Stmt, New_List); + end if; + + Append_To (Elsif_Parts (If_Stmt), + Make_Elsif_Part (Loc, + Condition => Cond, + Then_Statements => New_List (Prag))); + end if; + end Process_Increase_Decrease; + + -- Local variables + + Args : constant List_Id := Pragma_Argument_Associations (N); + Last_Arg : constant Node_Id := Last (Args); + Arg : Node_Id; + Invar : Node_Id := Empty; + + -- Start of processing for Expand_Pragma_Loop_Assertion + + begin + -- Locate the enclosing loop for which this assertion applies + + Loop_Scop := Current_Scope; + while Present (Loop_Scop) + and then Loop_Scop /= Standard_Standard + and then Ekind (Loop_Scop) /= E_Loop + loop + Loop_Scop := Scope (Loop_Scop); + end loop; + + Loop_Stmt := N; + while Present (Loop_Stmt) + and then Nkind (Loop_Stmt) /= N_Loop_Statement + loop + Loop_Stmt := Parent (Loop_Stmt); + end loop; + + -- Process all pragma arguments + + Arg := First (Args); + while Present (Arg) loop + if No (Invar) or else Chars (Arg) = Name_Invariant then + Invar := Expression (Arg); + else + Process_Increase_Decrease (Arg, Is_Last => Arg = Last_Arg); + end if; + + Next (Arg); + end loop; + + -- Verify the invariant expression, generate: + -- pragma Assert (<Invar>); + + Insert_Action (N, + Make_Pragma (Loc, + Chars => Name_Assert, + Pragma_Argument_Associations => New_List ( + Make_Pragma_Argument_Association (Loc, + Expression => Relocate_Node (Invar))))); + + -- Construct the segment which stores the old values of all expressions. + -- Generate: + -- if Flag then + -- <Old_Assign> + -- end if; + + if Present (Old_Assign) then + Insert_Action (N, + Make_If_Statement (Loc, + Condition => New_Reference_To (Flag_Id, Loc), + Then_Statements => Old_Assign)); + end if; + + -- Update the values of all expressions + + if Present (Curr_Assign) then + Insert_Actions (N, Curr_Assign); + end if; + + -- Add the assertion circuitry to test all changes in expressions. + -- Generate: + -- if Flag then + -- <If_Stmt> + -- else + -- Flag := True; + -- end if; + + if Present (If_Stmt) then + Insert_Action (N, + Make_If_Statement (Loc, + Condition => New_Reference_To (Flag_Id, Loc), + Then_Statements => New_List (If_Stmt), + Else_Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => New_Reference_To (Flag_Id, Loc), + Expression => New_Reference_To (Standard_True, Loc))))); + end if; + + Rewrite (N, Make_Null_Statement (Loc)); + Analyze (N); + end Expand_Pragma_Loop_Assertion; + -------------------------------- -- Expand_Pragma_Psect_Object -- -------------------------------- |