-- --
-- B o d y --
-- --
--- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- --
------------------------------------------------------------------------------
+with Aspects; use Aspects;
with Atree; use Atree;
with Checks; use Checks;
with Einfo; use Einfo;
with Errout; use Errout;
with Expander; use Expander;
+with Exp_Ch6; use Exp_Ch6;
with Exp_Util; use Exp_Util;
with Freeze; use Freeze;
with Lib; use Lib;
with Nlists; use Nlists;
with Nmake; use Nmake;
with Opt; use Opt;
+with Restrict; use Restrict;
+with Rident; use Rident;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Aux; use Sem_Aux;
with Sem_Case; use Sem_Case;
with Sem_Ch3; use Sem_Ch3;
+with Sem_Ch6; use Sem_Ch6;
with Sem_Ch8; use Sem_Ch8;
with Sem_Disp; use Sem_Disp;
with Sem_Elab; use Sem_Elab;
procedure Set_Assignment_Type
(Opnd : Node_Id;
Opnd_Type : in out Entity_Id);
- -- Opnd is either the Lhs or Rhs of the assignment, and Opnd_Type
- -- is the nominal subtype. This procedure is used to deal with cases
- -- where the nominal subtype must be replaced by the actual subtype.
+ -- Opnd is either the Lhs or Rhs of the assignment, and Opnd_Type is the
+ -- nominal subtype. This procedure is used to deal with cases where the
+ -- nominal subtype must be replaced by the actual subtype.
-------------------------------
-- Diagnose_Non_Variable_Lhs --
procedure Diagnose_Non_Variable_Lhs (N : Node_Id) is
begin
- -- Not worth posting another error if left hand side already
- -- flagged as being illegal in some respect.
+ -- Not worth posting another error if left hand side already flagged
+ -- as being illegal in some respect.
if Error_Posted (N) then
return;
elsif (Is_Prival (Ent)
and then
(Ekind (Current_Scope) = E_Function
- or else Ekind (Enclosing_Dynamic_Scope (
- Current_Scope)) = E_Function))
+ or else Ekind (Enclosing_Dynamic_Scope
+ (Current_Scope)) = E_Function))
or else
(Ekind (Ent) = E_Component
and then Is_Protected_Type (Scope (Ent)))
Require_Entity (Opnd);
-- If the assignment operand is an in-out or out parameter, then we
- -- get the actual subtype (needed for the unconstrained case).
- -- If the operand is the actual in an entry declaration, then within
- -- the accept statement it is replaced with a local renaming, which
- -- may also have an actual subtype.
+ -- get the actual subtype (needed for the unconstrained case). If the
+ -- operand is the actual in an entry declaration, then within the
+ -- accept statement it is replaced with a local renaming, which may
+ -- also have an actual subtype.
if Is_Entity_Name (Opnd)
and then (Ekind (Entity (Opnd)) = E_Out_Parameter
Analyze (Rhs);
Analyze (Lhs);
+ -- Ensure that we never do an assignment on a variable marked as
+ -- as Safe_To_Reevaluate.
+
+ pragma Assert (not Is_Entity_Name (Lhs)
+ or else Ekind (Entity (Lhs)) /= E_Variable
+ or else not Is_Safe_To_Reevaluate (Entity (Lhs)));
+
-- Start type analysis for assignment
T1 := Etype (Lhs);
end if;
end if;
- -- The resulting assignment type is T1, so now we will resolve the
- -- left hand side of the assignment using this determined type.
+ -- The resulting assignment type is T1, so now we will resolve the left
+ -- hand side of the assignment using this determined type.
Resolve (Lhs, T1);
if not Is_Variable (Lhs) then
- -- Ada 2005 (AI-327): Check assignment to the attribute Priority of
- -- a protected object.
+ -- Ada 2005 (AI-327): Check assignment to the attribute Priority of a
+ -- protected object.
declare
Ent : Entity_Id;
("target of assignment operation must not be abstract", Lhs);
end if;
- -- Resolution may have updated the subtype, in case the left-hand
- -- side is a private protected component. Use the correct subtype
- -- to avoid scoping issues in the back-end.
+ -- Resolution may have updated the subtype, in case the left-hand side
+ -- is a private protected component. Use the correct subtype to avoid
+ -- scoping issues in the back-end.
T1 := Etype (Lhs);
then
if Is_Local_Anonymous_Access (T1)
or else Ekind (T2) = E_Anonymous_Access_Subprogram_Type
+
+ -- Handle assignment to an Ada 2012 stand-alone object
+ -- of an anonymous access type.
+
+ or else (Ekind (T1) = E_Anonymous_Access_Type
+ and then Nkind (Associated_Node_For_Itype (T1)) =
+ N_Object_Declaration)
+
then
Rewrite (Rhs, Convert_To (T1, Relocate_Node (Rhs)));
Analyze_And_Resolve (Rhs, T1);
Apply_Scalar_Range_Check (Rhs, Etype (Lhs));
-- For array types, verify that lengths match. If the right hand side
- -- if a function call that has been inlined, the assignment has been
+ -- is a function call that has been inlined, the assignment has been
-- rewritten as a block, and the constraint check will be applied to the
-- assignment within the block.
-- side is a type conversion to an unconstrained type, a length check
-- is performed on the expression itself during expansion. In rare
-- cases, the redundant length check is computed on an index type
- -- with a different representation, triggering incorrect code in
- -- the back end.
+ -- with a different representation, triggering incorrect code in the
+ -- back end.
Apply_Length_Check (Rhs, Etype (Lhs));
and then Same_Object (Lhs, Original_Node (Rhs))
- -- But exclude the case where the right side was an operation
- -- that got rewritten (e.g. JUNK + K, where K was known to be
- -- zero). We don't want to warn in such a case, since it is
- -- reasonable to write such expressions especially when K is
- -- defined symbolically in some other package.
+ -- But exclude the case where the right side was an operation that
+ -- got rewritten (e.g. JUNK + K, where K was known to be zero). We
+ -- don't want to warn in such a case, since it is reasonable to write
+ -- such expressions especially when K is defined symbolically in some
+ -- other package.
and then Nkind (Original_Node (Rhs)) not in N_Op
then
Set_Referenced_Modified (Lhs, Out_Param => False);
end if;
- -- Final step. If left side is an entity, then we may be able to
- -- reset the current tracked values to new safe values. We only have
- -- something to do if the left side is an entity name, and expansion
- -- has not modified the node into something other than an assignment,
- -- and of course we only capture values if it is safe to do so.
+ -- Final step. If left side is an entity, then we may be able to reset
+ -- the current tracked values to new safe values. We only have something
+ -- to do if the left side is an entity name, and expansion has not
+ -- modified the node into something other than an assignment, and of
+ -- course we only capture values if it is safe to do so.
if Is_Entity_Name (Lhs)
and then Nkind (N) = N_Assignment_Statement
if Safe_To_Capture_Value (N, Ent) then
-- If simple variable on left side, warn if this assignment
- -- blots out another one (rendering it useless) and note
- -- location of assignment in case no one references value.
- -- We only do this for source assignments, otherwise we can
- -- generate bogus warnings when an assignment is rewritten as
- -- another assignment, and gets tied up with itself.
-
- -- Note: we don't use Record_Last_Assignment here, because we
- -- have lots of other stuff to do under control of this test.
+ -- blots out another one (rendering it useless). We only do
+ -- this for source assignments, otherwise we can generate bogus
+ -- warnings when an assignment is rewritten as another
+ -- assignment, and gets tied up with itself.
if Warn_On_Modified_Unread
and then Is_Assignable (Ent)
and then In_Extended_Main_Source_Unit (Ent)
then
Warn_On_Useless_Assignment (Ent, N);
- Set_Last_Assignment (Ent, Lhs);
end if;
-- If we are assigning an access type and the left side is an
end if;
end;
end if;
+
+ -- If assigning to an object in whole or in part, note location of
+ -- assignment in case no one references value. We only do this for
+ -- source assignments, otherwise we can generate bogus warnings when an
+ -- assignment is rewritten as another assignment, and gets tied up with
+ -- itself.
+
+ declare
+ Ent : constant Entity_Id := Get_Enclosing_Object (Lhs);
+
+ begin
+ if Present (Ent)
+ and then Safe_To_Capture_Value (N, Ent)
+ and then Nkind (N) = N_Assignment_Statement
+ and then Warn_On_Modified_Unread
+ and then Is_Assignable (Ent)
+ and then Comes_From_Source (N)
+ and then In_Extended_Main_Source_Unit (Ent)
+ then
+ Set_Last_Assignment (Ent, Lhs);
+ end if;
+ end;
end Analyze_Assignment;
-----------------------------
-----------------------------
procedure Analyze_Block_Statement (N : Node_Id) is
+ procedure Install_Return_Entities (Scop : Entity_Id);
+ -- Install all entities of return statement scope Scop in the visibility
+ -- chain except for the return object since its entity is reused in a
+ -- renaming.
+
+ -----------------------------
+ -- Install_Return_Entities --
+ -----------------------------
+
+ procedure Install_Return_Entities (Scop : Entity_Id) is
+ Id : Entity_Id;
+
+ begin
+ Id := First_Entity (Scop);
+ while Present (Id) loop
+
+ -- Do not install the return object
+
+ if not Ekind_In (Id, E_Constant, E_Variable)
+ or else not Is_Return_Object (Id)
+ then
+ Install_Entity (Id);
+ end if;
+
+ Next_Entity (Id);
+ end loop;
+ end Install_Return_Entities;
+
+ -- Local constants and variables
+
Decls : constant List_Id := Declarations (N);
Id : constant Node_Id := Identifier (N);
HSS : constant Node_Id := Handled_Statement_Sequence (N);
+ Is_BIP_Return_Statement : Boolean;
+
+ -- Start of processing for Analyze_Block_Statement
+
begin
- -- Block statement is not allowed in SPARK or ALFA
+ -- In SPARK mode, we reject block statements. Note that the case of
+ -- block statements generated by the expander is fine.
- if Formal_Verification_Mode then
- Formal_Error_Msg_N ("block statement is not allowed", N);
+ if Nkind (Original_Node (N)) = N_Block_Statement then
+ Check_SPARK_Restriction ("block statement is not allowed", N);
end if;
- -- If no handled statement sequence is present, things are really
- -- messed up, and we just return immediately (this is a defence
- -- against previous errors).
+ -- If no handled statement sequence is present, things are really messed
+ -- up, and we just return immediately (defence against previous errors).
if No (HSS) then
return;
end if;
+ -- Detect whether the block is actually a rewritten return statement of
+ -- a build-in-place function.
+
+ Is_BIP_Return_Statement :=
+ Present (Id)
+ and then Present (Entity (Id))
+ and then Ekind (Entity (Id)) = E_Return_Statement
+ and then Is_Build_In_Place_Function
+ (Return_Applies_To (Entity (Id)));
+
-- Normal processing with HSS present
declare
Analyze (Id);
Ent := Entity (Id);
- -- An error defense. If we have an identifier, but no entity,
- -- then something is wrong. If we have previous errors, then
- -- just remove the identifier and continue, otherwise raise
- -- an exception.
+ -- An error defense. If we have an identifier, but no entity, then
+ -- something is wrong. If previous errors, then just remove the
+ -- identifier and continue, otherwise raise an exception.
if No (Ent) then
if Total_Errors_Detected /= 0 then
Set_Block_Node (Ent, Identifier (N));
Push_Scope (Ent);
+ -- The block served as an extended return statement. Ensure that any
+ -- entities created during the analysis and expansion of the return
+ -- object declaration are once again visible.
+
+ if Is_BIP_Return_Statement then
+ Install_Return_Entities (Ent);
+ end if;
+
if Present (Decls) then
Analyze_Declarations (Decls);
Check_Completion;
Analyze (HSS);
Process_End_Label (HSS, 'e', Ent);
- -- If exception handlers are present, then we indicate that
- -- enclosing scopes contain a block with handlers. We only
- -- need to mark non-generic scopes.
+ -- If exception handlers are present, then we indicate that enclosing
+ -- scopes contain a block with handlers. We only need to mark non-
+ -- generic scopes.
if Present (EH) then
S := Scope (Ent);
-- Don't care about assigned values
Statements_Analyzed : Boolean := False;
- -- Set True if at least some statement sequences get analyzed.
- -- If False on exit, means we had a serious error that prevented
- -- full analysis of the case statement, and as a result it is not
- -- a good idea to output warning messages about unreachable code.
+ -- Set True if at least some statement sequences get analyzed. If False
+ -- on exit, means we had a serious error that prevented full analysis of
+ -- the case statement, and as a result it is not a good idea to output
+ -- warning messages about unreachable code.
Save_Unblocked_Exit_Count : constant Nat := Unblocked_Exit_Count;
-- Recursively save value of this global, will be restored on exit
procedure Non_Static_Choice_Error (Choice : Node_Id);
- -- Error routine invoked by the generic instantiation below when
- -- the case statement has a non static choice.
+ -- Error routine invoked by the generic instantiation below when the
+ -- case statement has a non static choice.
procedure Process_Statements (Alternative : Node_Id);
-- Analyzes all the statements associated with a case alternative.
Statements_Analyzed := True;
-- An interesting optimization. If the case statement expression
- -- is a simple entity, then we can set the current value within
- -- an alternative if the alternative has one possible value.
+ -- is a simple entity, then we can set the current value within an
+ -- alternative if the alternative has one possible value.
-- case N is
-- when 1 => alpha
-- when 2 | 3 => beta
-- when others => gamma
- -- Here we know that N is initially 1 within alpha, but for beta
- -- and gamma, we do not know anything more about the initial value.
+ -- Here we know that N is initially 1 within alpha, but for beta and
+ -- gamma, we do not know anything more about the initial value.
if Is_Entity_Name (Exp) then
Ent := Entity (Exp);
return;
end if;
- -- If the case expression is a formal object of mode in out, then
- -- treat it as having a nonstatic subtype by forcing use of the base
- -- type (which has to get passed to Check_Case_Choices below). Also
- -- use base type when the case expression is parenthesized.
+ -- If the case expression is a formal object of mode in out, then treat
+ -- it as having a nonstatic subtype by forcing use of the base type
+ -- (which has to get passed to Check_Case_Choices below). Also use base
+ -- type when the case expression is parenthesized.
if Paren_Count (Exp) > 0
or else (Is_Entity_Name (Exp)
Analyze_Choices (N, Exp_Type, Dont_Care, Others_Present);
- -- A case statement with a single "others" alternative is not allowed
- -- in SPARK or ALFA
+ -- A case statement with a single OTHERS alternative is not allowed
+ -- in SPARK.
- if Formal_Verification_Mode
- and then Others_Present
+ if Others_Present
and then List_Length (Alternatives (N)) = 1
then
- Formal_Error_Msg_N
+ Check_SPARK_Restriction
("OTHERS as unique case alternative is not allowed", N);
end if;
----------------------------
-- If the exit includes a name, it must be the name of a currently open
- -- loop. Otherwise there must be an innermost open loop on the stack,
- -- to which the statement implicitly refers.
+ -- loop. Otherwise there must be an innermost open loop on the stack, to
+ -- which the statement implicitly refers.
+
+ -- Additionally, in SPARK mode:
+
+ -- The exit can only name the closest enclosing loop;
+
+ -- An exit with a when clause must be directly contained in a loop;
- -- Additionally, in formal mode:
- -- * the exit can only name the closest enclosing loop;
- -- * an exit with a when clause must be directly contained in a loop;
- -- * an exit without a when clause must be directly contained in an
+ -- An exit without a when clause must be directly contained in an
-- if-statement with no elsif or else, which is itself directly contained
-- in a loop. The exit must be the last statement in the if-statement.
if not In_Open_Scopes (U_Name) or else Ekind (U_Name) /= E_Loop then
Error_Msg_N ("invalid loop name in exit statement", N);
return;
- elsif Formal_Verification_Mode
- and then Has_Loop_In_Inner_Open_Scopes (U_Name)
- then
- Formal_Error_Msg_N
- ("exit label must name the closest enclosing loop", N);
+
else
+ if Has_Loop_In_Inner_Open_Scopes (U_Name) then
+ Check_SPARK_Restriction
+ ("exit label must name the closest enclosing loop", N);
+ end if;
+
Set_Has_Exit (U_Name);
end if;
Kind := Ekind (Scope_Id);
if Kind = E_Loop
- and then (No (Target) or else Scope_Id = U_Name) then
+ and then (No (Target) or else Scope_Id = U_Name)
+ then
Set_Has_Exit (Scope_Id);
exit;
Check_Unset_Reference (Cond);
end if;
- -- In formal mode, verify that the exit statement respects the SPARK
- -- restrictions
+ -- In SPARK mode, verify that the exit statement respects the SPARK
+ -- restrictions.
- if Formal_Verification_Mode then
- if Present (Cond) then
- if Nkind (Parent (N)) /= N_Loop_Statement then
- Formal_Error_Msg_N
- ("exit with when clause must be directly in loop", N);
+ if Present (Cond) then
+ if Nkind (Parent (N)) /= N_Loop_Statement then
+ Check_SPARK_Restriction
+ ("exit with when clause must be directly in loop", N);
+ end if;
+
+ else
+ if Nkind (Parent (N)) /= N_If_Statement then
+ if Nkind (Parent (N)) = N_Elsif_Part then
+ Check_SPARK_Restriction
+ ("exit must be in IF without ELSIF", N);
+ else
+ Check_SPARK_Restriction ("exit must be directly in IF", N);
end if;
- else
- if Nkind (Parent (N)) /= N_If_Statement then
- if Nkind (Parent (N)) = N_Elsif_Part then
- Formal_Error_Msg_N ("exit must be in IF without ELSIF", N);
- else
- Formal_Error_Msg_N ("exit must be directly in IF", N);
- end if;
- elsif Nkind (Parent (Parent (N))) /= N_Loop_Statement then
- Formal_Error_Msg_N ("exit must be in IF directly in loop", N);
- -- First test the presence of ELSE, so that an exit in an ELSE
- -- leads to an error mentioning the ELSE
+ elsif Nkind (Parent (Parent (N))) /= N_Loop_Statement then
+ Check_SPARK_Restriction
+ ("exit must be in IF directly in loop", N);
- elsif Present (Else_Statements (Parent (N))) then
- Formal_Error_Msg_N ("exit must be in IF without ELSE", N);
+ -- First test the presence of ELSE, so that an exit in an ELSE leads
+ -- to an error mentioning the ELSE.
- -- An exit in an ELSIF does not reach here, as it would have been
- -- detected in the case (Nkind (Parent (N)) /= N_If_Statement)
+ elsif Present (Else_Statements (Parent (N))) then
+ Check_SPARK_Restriction ("exit must be in IF without ELSE", N);
- elsif Present (Elsif_Parts (Parent (N))) then
- Formal_Error_Msg_N ("exit must be in IF without ELSIF", N);
- end if;
+ -- An exit in an ELSIF does not reach here, as it would have been
+ -- detected in the case (Nkind (Parent (N)) /= N_If_Statement).
+
+ elsif Present (Elsif_Parts (Parent (N))) then
+ Check_SPARK_Restriction ("exit must be in IF without ELSIF", N);
end if;
end if;
Label_Ent : Entity_Id;
begin
- -- Goto statement is not allowed in SPARK or ALFA
-
- if Formal_Verification_Mode then
- Formal_Error_Msg_N ("goto statement is not allowed", N);
- end if;
+ Check_SPARK_Restriction ("goto statement is not allowed", N);
-- Actual semantic checks
-- A special complication arises in the analysis of if statements
- -- The expander has circuitry to completely delete code that it
- -- can tell will not be executed (as a result of compile time known
- -- conditions). In the analyzer, we ensure that code that will be
- -- deleted in this manner is analyzed but not expanded. This is
- -- obviously more efficient, but more significantly, difficulties
- -- arise if code is expanded and then eliminated (e.g. exception
- -- table entries disappear). Similarly, itypes generated in deleted
- -- code must be frozen from start, because the nodes on which they
- -- depend will not be available at the freeze point.
+ -- The expander has circuitry to completely delete code that it can tell
+ -- will not be executed (as a result of compile time known conditions). In
+ -- the analyzer, we ensure that code that will be deleted in this manner is
+ -- analyzed but not expanded. This is obviously more efficient, but more
+ -- significantly, difficulties arise if code is expanded and then
+ -- eliminated (e.g. exception table entries disappear). Similarly, itypes
+ -- generated in deleted code must be frozen from start, because the nodes
+ -- on which they depend will not be available at the freeze point.
procedure Analyze_If_Statement (N : Node_Id) is
E : Node_Id;
Save_In_Deleted_Code : Boolean;
Del : Boolean := False;
- -- This flag gets set True if a True condition has been found,
- -- which means that remaining ELSE/ELSIF parts are deleted.
+ -- This flag gets set True if a True condition has been found, which
+ -- means that remaining ELSE/ELSIF parts are deleted.
procedure Analyze_Cond_Then (Cnode : Node_Id);
- -- This is applied to either the N_If_Statement node itself or
- -- to an N_Elsif_Part node. It deals with analyzing the condition
- -- and the THEN statements associated with it.
+ -- This is applied to either the N_If_Statement node itself or to an
+ -- N_Elsif_Part node. It deals with analyzing the condition and the THEN
+ -- statements associated with it.
-----------------------
-- Analyze_Cond_Then --
elsif Compile_Time_Known_Value (Cond) then
Save_In_Deleted_Code := In_Deleted_Code;
- -- If condition is True, then analyze the THEN statements
- -- and set no expansion for ELSE and ELSIF parts.
+ -- If condition is True, then analyze the THEN statements and set
+ -- no expansion for ELSE and ELSIF parts.
if Is_True (Expr_Value (Cond)) then
Analyze_Statements (Tstm);
-- Start of Analyze_If_Statement
begin
- -- Initialize exit count for else statements. If there is no else
- -- part, this count will stay non-zero reflecting the fact that the
- -- uncovered else case is an unblocked exit.
+ -- Initialize exit count for else statements. If there is no else part,
+ -- this count will stay non-zero reflecting the fact that the uncovered
+ -- else case is an unblocked exit.
Unblocked_Exit_Count := 1;
Analyze_Cond_Then (N);
-- Analyze_Implicit_Label_Declaration --
----------------------------------------
- -- An implicit label declaration is generated in the innermost
- -- enclosing declarative part. This is done for labels as well as
- -- block and loop names.
+ -- An implicit label declaration is generated in the innermost enclosing
+ -- declarative part. This is done for labels, and block and loop names.
-- Note: any changes in this routine may need to be reflected in
-- Analyze_Label_Entity.
-- to capture the bounds, so that the function result can be finalized
-- in timely fashion.
+ function Has_Call_Using_Secondary_Stack (N : Node_Id) return Boolean;
+ -- N is the node for an arbitrary construct. This function searches the
+ -- construct N to see if any expressions within it contain function
+ -- calls that use the secondary stack, returning True if any such call
+ -- is found, and False otherwise.
+
+ procedure Pre_Analyze_Range (R_Copy : Node_Id);
+ -- Determine expected type of range or domain of iteration of Ada 2012
+ -- loop by analyzing separate copy. Do the analysis and resolution of
+ -- the copy of the bound(s) with expansion disabled, to prevent the
+ -- generation of finalization actions. This prevents memory leaks when
+ -- the bounds contain calls to functions returning controlled arrays or
+ -- when the domain of iteration is a container.
+
+ -----------------------
+ -- Pre_Analyze_Range --
+ -----------------------
+
+ procedure Pre_Analyze_Range (R_Copy : Node_Id) is
+ Save_Analysis : Boolean;
+ begin
+ Save_Analysis := Full_Analysis;
+ Full_Analysis := False;
+ Expander_Mode_Save_And_Set (False);
+
+ Analyze (R_Copy);
+
+ if Nkind (R_Copy) in N_Subexpr
+ and then Is_Overloaded (R_Copy)
+ then
+
+ -- Apply preference rules for range of predefined integer types,
+ -- or diagnose true ambiguity.
+
+ declare
+ I : Interp_Index;
+ It : Interp;
+ Found : Entity_Id := Empty;
+
+ begin
+ Get_First_Interp (R_Copy, I, It);
+ while Present (It.Typ) loop
+ if Is_Discrete_Type (It.Typ) then
+ if No (Found) then
+ Found := It.Typ;
+ else
+ if Scope (Found) = Standard_Standard then
+ null;
+
+ elsif Scope (It.Typ) = Standard_Standard then
+ Found := It.Typ;
+
+ else
+ -- Both of them are user-defined
+
+ Error_Msg_N
+ ("ambiguous bounds in range of iteration",
+ R_Copy);
+ Error_Msg_N ("\possible interpretations:", R_Copy);
+ Error_Msg_NE ("\\} ", R_Copy, Found);
+ Error_Msg_NE ("\\} ", R_Copy, It.Typ);
+ exit;
+ end if;
+ end if;
+ end if;
+
+ Get_Next_Interp (I, It);
+ end loop;
+ end;
+ end if;
+
+ if Is_Entity_Name (R_Copy)
+ and then Is_Type (Entity (R_Copy))
+ then
+
+ -- Subtype mark in iteration scheme
+
+ null;
+
+ elsif Nkind (R_Copy) in N_Subexpr then
+
+ -- Expression in range, or Ada 2012 iterator
+
+ Resolve (R_Copy);
+ end if;
+
+ Expander_Mode_Restore;
+ Full_Analysis := Save_Analysis;
+ end Pre_Analyze_Range;
+
--------------------
-- Process_Bounds --
--------------------
New_Lo_Bound : Node_Id;
New_Hi_Bound : Node_Id;
Typ : Entity_Id;
- Save_Analysis : Boolean;
function One_Bound
(Original_Bound : Node_Id;
Analyze_And_Resolve (Original_Bound, Typ);
- Id := Make_Temporary (Loc, 'S', Original_Bound);
-
-- Normally, the best approach is simply to generate a constant
-- declaration that captures the bound. However, there is a nasty
-- case where this is wrong. If the bound is complex, and has a
-- proper trace of the value, useful in optimizations that get rid
-- of junk range checks.
- -- Probably we want something like the Side_Effect_Free routine
- -- in Exp_Util, but for now, we just optimize the cases of 'Last
- -- and 'First applied to an entity, since these are the important
- -- cases for range check optimizations.
-
- if Nkind (Original_Bound) = N_Attribute_Reference
- and then (Attribute_Name (Original_Bound) = Name_First
- or else
- Attribute_Name (Original_Bound) = Name_Last)
- and then Is_Entity_Name (Prefix (Original_Bound))
- then
- Decl :=
- Make_Object_Declaration (Loc,
- Defining_Identifier => Id,
- Constant_Present => True,
- Object_Definition => New_Occurrence_Of (Typ, Loc),
- Expression => Relocate_Node (Original_Bound));
-
- -- Insert declaration at proper place. If loop comes from an
- -- enclosing quantified expression, the insertion point is
- -- arbitrarily far up in the tree.
-
- Insert_Action (Parent (N), Decl);
- Rewrite (Original_Bound, New_Occurrence_Of (Id, Loc));
- return Expression (Decl);
+ if not Has_Call_Using_Secondary_Stack (Original_Bound) then
+ Force_Evaluation (Original_Bound);
+ return Original_Bound;
end if;
+ Id := Make_Temporary (Loc, 'R', Original_Bound);
+
-- Here we make a declaration with a separate assignment
- -- statement, and insert before loop header.
+ -- statement, and insert before loop header.
Decl :=
Make_Object_Declaration (Loc,
Name => New_Occurrence_Of (Id, Loc),
Expression => Relocate_Node (Original_Bound));
+ -- We must recursively clean in the relocated expression the flag
+ -- analyzed to ensure that the expression is reanalyzed. Required
+ -- to ensure that the transient scope is established now (because
+ -- Establish_Transient_Scope discarded generating transient scopes
+ -- in the analysis of the iteration scheme).
+
+ Reset_Analyzed_Flags (Expression (Assign));
+
Insert_Actions (Parent (N), New_List (Decl, Assign));
+ -- Now that this temporary variable is initialized we decorate it
+ -- as safe-to-reevaluate to inform to the backend that no further
+ -- asignment will be issued and hence it can be handled as side
+ -- effect free. Note that this decoration must be done when the
+ -- assignment has been analyzed because otherwise it will be
+ -- rejected (see Analyze_Assignment).
+
+ Set_Is_Safe_To_Reevaluate (Id);
+
Rewrite (Original_Bound, New_Occurrence_Of (Id, Loc));
if Nkind (Assign) = N_Assignment_Statement then
-- Start of processing for Process_Bounds
begin
- -- Determine expected type of range by analyzing separate copy
- -- Do the analysis and resolution of the copy of the bounds with
- -- expansion disabled, to prevent the generation of finalization
- -- actions on each bound. This prevents memory leaks when the
- -- bounds contain calls to functions returning controlled arrays.
-
Set_Parent (R_Copy, Parent (R));
- Save_Analysis := Full_Analysis;
- Full_Analysis := False;
- Expander_Mode_Save_And_Set (False);
-
- Analyze (R_Copy);
-
- if Is_Overloaded (R_Copy) then
-
- -- Apply preference rules for range of predefined integer types,
- -- or diagnose true ambiguity.
-
- declare
- I : Interp_Index;
- It : Interp;
- Found : Entity_Id := Empty;
-
- begin
- Get_First_Interp (R_Copy, I, It);
- while Present (It.Typ) loop
- if Is_Discrete_Type (It.Typ) then
- if No (Found) then
- Found := It.Typ;
- else
- if Scope (Found) = Standard_Standard then
- null;
-
- elsif Scope (It.Typ) = Standard_Standard then
- Found := It.Typ;
-
- else
- -- Both of them are user-defined
-
- Error_Msg_N
- ("ambiguous bounds in range of iteration",
- R_Copy);
- Error_Msg_N ("\possible interpretations:", R_Copy);
- Error_Msg_NE ("\\} ", R_Copy, Found);
- Error_Msg_NE ("\\} ", R_Copy, It.Typ);
- exit;
- end if;
- end if;
- end if;
-
- Get_Next_Interp (I, It);
- end loop;
- end;
- end if;
-
- Resolve (R_Copy);
- Expander_Mode_Restore;
- Full_Analysis := Save_Analysis;
-
+ Pre_Analyze_Range (R_Copy);
Typ := Etype (R_Copy);
- -- If the type of the discrete range is Universal_Integer, then
- -- the bound's type must be resolved to Integer, and any object
- -- used to hold the bound must also have type Integer, unless the
- -- literal bounds are constant-folded expressions that carry a user-
- -- defined type.
+ -- If the type of the discrete range is Universal_Integer, then the
+ -- bound's type must be resolved to Integer, and any object used to
+ -- hold the bound must also have type Integer, unless the literal
+ -- bounds are constant-folded expressions with a user-defined type.
if Typ = Universal_Integer then
if Nkind (Lo) = N_Integer_Literal
end if;
end Check_Controlled_Array_Attribute;
+ ------------------------------------
+ -- Has_Call_Using_Secondary_Stack --
+ ------------------------------------
+
+ function Has_Call_Using_Secondary_Stack (N : Node_Id) return Boolean is
+
+ function Check_Call (N : Node_Id) return Traverse_Result;
+ -- Check if N is a function call which uses the secondary stack
+
+ ----------------
+ -- Check_Call --
+ ----------------
+
+ function Check_Call (N : Node_Id) return Traverse_Result is
+ Nam : Node_Id;
+ Subp : Entity_Id;
+ Return_Typ : Entity_Id;
+
+ begin
+ if Nkind (N) = N_Function_Call then
+ Nam := Name (N);
+
+ -- Call using access to subprogram with explicit dereference
+
+ if Nkind (Nam) = N_Explicit_Dereference then
+ Subp := Etype (Nam);
+
+ -- Normal case
+
+ else
+ Subp := Entity (Nam);
+ end if;
+
+ Return_Typ := Etype (Subp);
+
+ if Is_Composite_Type (Return_Typ)
+ and then not Is_Constrained (Return_Typ)
+ then
+ return Abandon;
+
+ elsif Sec_Stack_Needed_For_Return (Subp) then
+ return Abandon;
+ end if;
+ end if;
+
+ -- Continue traversing the tree
+
+ return OK;
+ end Check_Call;
+
+ function Check_Calls is new Traverse_Func (Check_Call);
+
+ -- Start of processing for Has_Call_Using_Secondary_Stack
+
+ begin
+ return Check_Calls (N) = Abandon;
+ end Has_Call_Using_Secondary_Stack;
+
-- Start of processing for Analyze_Iteration_Scheme
begin
- -- If this is a rewritten quantified expression, the iteration
- -- scheme has been analyzed already. Do no repeat analysis because
- -- the loop variable is already declared.
+ -- If this is a rewritten quantified expression, the iteration scheme
+ -- has been analyzed already. Do no repeat analysis because the loop
+ -- variable is already declared.
if Analyzed (N) then
return;
Cond : constant Node_Id := Condition (N);
begin
- -- For WHILE loop, verify that the condition is a Boolean
- -- expression and resolve and check it.
+ -- For WHILE loop, verify that the condition is a Boolean expression
+ -- and resolve and check it.
if Present (Cond) then
Analyze_And_Resolve (Cond, Any_Boolean);
Set_Current_Value_Condition (N);
return;
+ -- For an iterator specification with "of", pre-analyze range to
+ -- capture function calls that may require finalization actions.
+
elsif Present (Iterator_Specification (N)) then
+ Pre_Analyze_Range (Name (Iterator_Specification (N)));
Analyze_Iterator_Specification (Iterator_Specification (N));
-- Else we have a FOR loop
Id : constant Entity_Id := Defining_Identifier (LP);
DS : constant Node_Id := Discrete_Subtype_Definition (LP);
+ D_Copy : Node_Id;
+
begin
Enter_Name (Id);
- -- We always consider the loop variable to be referenced,
- -- since the loop may be used just for counting purposes.
+ -- We always consider the loop variable to be referenced, since
+ -- the loop may be used just for counting purposes.
Generate_Reference (Id, N, ' ');
end if;
end;
+ -- Loop parameter specification must include subtype mark in
+ -- SPARK.
+
+ if Nkind (DS) = N_Range then
+ Check_SPARK_Restriction
+ ("loop parameter specification must include subtype mark",
+ N);
+ end if;
+
-- Now analyze the subtype definition. If it is a range, create
-- temporaries for bounds.
then
Process_Bounds (DS);
- -- Not a range or expander not active (is that right???)
+ -- expander not active or else range of iteration is a subtype
+ -- indication, an entity, or a function call that yields an
+ -- aggregate or a container.
else
- Analyze (DS);
+ D_Copy := New_Copy_Tree (DS);
+ Set_Parent (D_Copy, Parent (DS));
+ Pre_Analyze_Range (D_Copy);
+
+ -- Ada 2012: If the domain of iteration is a function call,
+ -- it is the new iterator form.
+
+ -- We have also implemented the shorter form : for X in S
+ -- for Alfa use. In this case, 'Old and 'Result must be
+ -- treated as entity names over which iterators are legal.
- if Nkind (DS) = N_Function_Call
+ if Nkind (D_Copy) = N_Function_Call
+ or else
+ (Alfa_Mode
+ and then (Nkind (D_Copy) = N_Attribute_Reference
+ and then
+ (Attribute_Name (D_Copy) = Name_Result
+ or else Attribute_Name (D_Copy) = Name_Old)))
or else
- (Is_Entity_Name (DS)
- and then not Is_Type (Entity (DS)))
+ (Is_Entity_Name (D_Copy)
+ and then not Is_Type (Entity (D_Copy)))
then
-- This is an iterator specification. Rewrite as such
- -- and analyze.
+ -- and analyze, to capture function calls that may
+ -- require finalization actions.
declare
I_Spec : constant Node_Id :=
Make_Iterator_Specification (Sloc (LP),
Defining_Identifier =>
Relocate_Node (Id),
- Name =>
- Relocate_Node (DS),
- Subtype_Indication =>
- Empty,
+ Name => D_Copy,
+ Subtype_Indication => Empty,
Reverse_Present =>
Reverse_Present (LP));
begin
Set_Iterator_Specification (N, I_Spec);
Set_Loop_Parameter_Specification (N, Empty);
Analyze_Iterator_Specification (I_Spec);
+
+ -- In a generic context, analyze the original domain
+ -- of iteration, for name capture.
+
+ if not Expander_Active then
+ Analyze (DS);
+ end if;
+
+ -- Set kind of loop parameter, which may be used in
+ -- the subsequent analysis of the condition in a
+ -- quantified expression.
+
+ Set_Ekind (Id, E_Loop_Parameter);
return;
end;
+
+ -- Domain of iteration is not a function call, and is
+ -- side-effect free.
+
+ else
+ Analyze (DS);
end if;
end if;
Check_Controlled_Array_Attribute (DS);
- Make_Index (DS, LP);
+ Make_Index (DS, LP, In_Iter_Schm => True);
Set_Ekind (Id, E_Loop_Parameter);
if not Inside_A_Generic
and then not In_Instance
then
- -- Specialize msg if invalid values could make
- -- the loop non-null after all.
+ -- Specialize msg if invalid values could make the
+ -- loop non-null after all.
if Compile_Time_Compare
(L, H, Assume_Valid => False) = GT
("?loop range is null, loop will not execute",
DS);
- -- Since we know the range of the loop is
- -- null, set the appropriate flag to remove
- -- the loop entirely during expansion.
+ -- Since we know the range of the loop is null,
+ -- set the appropriate flag to remove the loop
+ -- entirely during expansion.
Set_Is_Null_Loop (Parent (N));
-------------------------------------
procedure Analyze_Iterator_Specification (N : Node_Id) is
- Def_Id : constant Node_Id := Defining_Identifier (N);
- Subt : constant Node_Id := Subtype_Indication (N);
- Container : constant Node_Id := Name (N);
+ Loc : constant Source_Ptr := Sloc (N);
+ Def_Id : constant Node_Id := Defining_Identifier (N);
+ Subt : constant Node_Id := Subtype_Indication (N);
+ Iter_Name : constant Node_Id := Name (N);
Ent : Entity_Id;
Typ : Entity_Id;
begin
- Enter_Name (Def_Id);
+ -- In semantics/Alfa modes, we won't be further expanding the loop, so
+ -- introduce loop variable so that loop body can be properly analyzed.
+ -- Otherwise this happens after expansion.
+
+ if Operating_Mode = Check_Semantics
+ or else Alfa_Mode
+ then
+ Enter_Name (Def_Id);
+ end if;
+
Set_Ekind (Def_Id, E_Variable);
if Present (Subt) then
Analyze (Subt);
end if;
- Analyze_And_Resolve (Container);
- Typ := Etype (Container);
+ -- If domain of iteration is an expression, create a declaration for
+ -- it, so that finalization actions are introduced outside of the loop.
+ -- The declaration must be a renaming because the body of the loop may
+ -- assign to elements.
+
+ if not Is_Entity_Name (Iter_Name) then
+ declare
+ Id : constant Entity_Id := Make_Temporary (Loc, 'R', Iter_Name);
+ Decl : Node_Id;
+
+ begin
+ Typ := Etype (Iter_Name);
+
+ Decl :=
+ Make_Object_Renaming_Declaration (Loc,
+ Defining_Identifier => Id,
+ Subtype_Mark => New_Occurrence_Of (Typ, Loc),
+ Name => Relocate_Node (Iter_Name));
+
+ Insert_Actions (Parent (Parent (N)), New_List (Decl));
+ Rewrite (Name (N), New_Occurrence_Of (Id, Loc));
+ Set_Etype (Id, Typ);
+ Set_Etype (Name (N), Typ);
+ end;
+
+ -- Container is an entity or an array with uncontrolled components, or
+ -- else it is a container iterator given by a function call, typically
+ -- called Iterate in the case of predefined containers, even though
+ -- Iterate is not a reserved name. What matter is that the return type
+ -- of the function is an iterator type.
+
+ else
+ Analyze (Iter_Name);
+
+ if Nkind (Iter_Name) = N_Function_Call then
+ declare
+ C : constant Node_Id := Name (Iter_Name);
+ I : Interp_Index;
+ It : Interp;
+
+ begin
+ if not Is_Overloaded (Iter_Name) then
+ Resolve (Iter_Name, Etype (C));
+
+ else
+ Get_First_Interp (C, I, It);
+ while It.Typ /= Empty loop
+ if Reverse_Present (N) then
+ if Is_Reversible_Iterator (It.Typ) then
+ Resolve (Iter_Name, It.Typ);
+ exit;
+ end if;
+
+ elsif Is_Iterator (It.Typ) then
+ Resolve (Iter_Name, It.Typ);
+ exit;
+ end if;
+
+ Get_Next_Interp (I, It);
+ end loop;
+ end if;
+ end;
+
+ -- Domain of iteration is not overloaded
+
+ else
+ Resolve (Iter_Name, Etype (Iter_Name));
+ end if;
+ end if;
+
+ Typ := Etype (Iter_Name);
if Is_Array_Type (Typ) then
if Of_Present (N) then
Set_Etype (Def_Id, Component_Type (Typ));
+
+ -- Here we have a missing Range attribute
+
else
Error_Msg_N
- ("to iterate over the elements of an array, use OF", N);
+ ("missing Range attribute in iteration over an array", N);
+
+ -- In Ada 2012 mode, this may be an attempt at an iterator
+
+ if Ada_Version >= Ada_2012 then
+ Error_Msg_NE
+ ("\if& is meant to designate an element of the array, use OF",
+ N, Def_Id);
+ end if;
+
+ -- Prevent cascaded errors
+
+ Set_Ekind (Def_Id, E_Loop_Parameter);
Set_Etype (Def_Id, Etype (First_Index (Typ)));
end if;
+ -- Check for type error in iterator
+
+ elsif Typ = Any_Type then
+ return;
+
-- Iteration over a container
else
if Of_Present (N) then
- -- Find the Element_Type in the package instance that defines the
- -- container type.
+ -- The type of the loop variable is the Iterator_Element aspect of
+ -- the container type.
- Ent := First_Entity (Scope (Typ));
- while Present (Ent) loop
- if Chars (Ent) = Name_Element_Type then
- Set_Etype (Def_Id, Ent);
- exit;
- end if;
-
- Next_Entity (Ent);
- end loop;
+ Set_Etype (Def_Id,
+ Entity (Find_Aspect (Typ, Aspect_Iterator_Element)));
else
- -- Find the Cursor type in similar fashion
+ -- For an iteration of the form IN, the name must denote an
+ -- iterator, typically the result of a call to Iterate. Give a
+ -- useful error message when the name is a container by itself.
+
+ if Is_Entity_Name (Original_Node (Name (N)))
+ and then not Is_Iterator (Typ)
+ then
+ Error_Msg_N
+ ("name must be an iterator, not a container", Name (N));
+
+ Error_Msg_NE
+ ("\to iterate directly over a container, write `of &`",
+ Name (N), Original_Node (Name (N)));
+ end if;
+
+ -- The result type of Iterate function is the classwide type of
+ -- the interface parent. We need the specific Cursor type defined
+ -- in the container package.
Ent := First_Entity (Scope (Typ));
while Present (Ent) loop
if Chars (Ent) = Name_Cursor then
- Set_Etype (Def_Id, Ent);
+ Set_Etype (Def_Id, Etype (Ent));
exit;
end if;
begin
if Present (Id) then
- -- Make name visible, e.g. for use in exit statements. Loop
- -- labels are always considered to be referenced.
+ -- Make name visible, e.g. for use in exit statements. Loop labels
+ -- are always considered to be referenced.
Analyze (Id);
Ent := Entity (Id);
Set_Parent (Ent, Loop_Statement);
end if;
- -- Kill current values on entry to loop, since statements in body of
- -- loop may have been executed before the loop is entered. Similarly we
- -- kill values after the loop, since we do not know that the body of the
- -- loop was executed.
+ -- Kill current values on entry to loop, since statements in the body of
+ -- the loop may have been executed before the loop is entered. Similarly
+ -- we kill values after the loop, since we do not know that the body of
+ -- the loop was executed.
Kill_Current_Values;
Push_Scope (Ent);
Analyze_Iteration_Scheme (Iter);
- Analyze_Statements (Statements (Loop_Statement));
+
+ -- Analyze the statements of the body except in the case of an Ada 2012
+ -- iterator with the expander active. In this case the expander will do
+ -- a rewrite of the loop into a while loop. We will then analyze the
+ -- loop body when we analyze this while loop.
+
+ -- We need to do this delay because if the container is for indefinite
+ -- types the actual subtype of the components will only be determined
+ -- when the cursor declaration is analyzed.
+
+ -- If the expander is not active, then we want to analyze the loop body
+ -- now even in the Ada 2012 iterator case, since the rewriting will not
+ -- be done. Insert the loop variable in the current scope, if not done
+ -- when analysing the iteration scheme.
+
+ if No (Iter)
+ or else No (Iterator_Specification (Iter))
+ or else not Expander_Active
+ then
+ if Present (Iter)
+ and then Present (Iterator_Specification (Iter))
+ then
+ declare
+ Id : constant Entity_Id :=
+ Defining_Identifier (Iterator_Specification (Iter));
+ begin
+ if Scope (Id) /= Current_Scope then
+ Enter_Name (Id);
+ end if;
+ end;
+ end if;
+
+ Analyze_Statements (Statements (Loop_Statement));
+ end if;
+
+ -- Finish up processing for the loop. We kill all current values, since
+ -- in general we don't know if the statements in the loop have been
+ -- executed. We could do a bit better than this with a loop that we
+ -- know will execute at least once, but it's not worth the trouble and
+ -- the front end is not in the business of flow tracing.
+
Process_End_Label (Loop_Statement, 'e', Ent);
End_Scope;
Kill_Current_Values;
Check_Infinite_Loop_Warning (N);
end if;
- -- Code after loop is unreachable if the loop has no WHILE or FOR
- -- and contains no EXIT statements within the body of the loop.
+ -- Code after loop is unreachable if the loop has no WHILE or FOR and
+ -- contains no EXIT statements within the body of the loop.
if No (Iter) and then not Has_Exit (Ent) then
Check_Unreachable_Code (N);
begin
-- The labels declared in the statement list are reachable from
- -- statements in the list. We do this as a prepass so that any
- -- goto statement will be properly flagged if its target is not
- -- reachable. This is not required, but is nice behavior!
+ -- statements in the list. We do this as a prepass so that any goto
+ -- statement will be properly flagged if its target is not reachable.
+ -- This is not required, but is nice behavior!
S := First (L);
while Present (S) loop
Conditional_Statements_End;
- -- Make labels unreachable. Visibility is not sufficient, because
- -- labels in one if-branch for example are not reachable from the
- -- other branch, even though their declarations are in the enclosing
- -- declarative part.
+ -- Make labels unreachable. Visibility is not sufficient, because labels
+ -- in one if-branch for example are not reachable from the other branch,
+ -- even though their declarations are in the enclosing declarative part.
S := First (L);
while Present (S) loop
----------------------------
procedure Check_Unreachable_Code (N : Node_Id) is
- Error_Loc : Source_Ptr;
- P : Node_Id;
+ Error_Node : Node_Id;
+ P : Node_Id;
begin
if Is_List_Member (N)
Nxt := Original_Node (Next (N));
-- If a label follows us, then we never have dead code, since
- -- someone could branch to the label, so we just ignore it,
- -- unless we are in formal mode where goto statements are not
- -- allowed.
+ -- someone could branch to the label, so we just ignore it, unless
+ -- we are in formal mode where goto statements are not allowed.
- if Nkind (Nxt) = N_Label and then not Formal_Verification_Mode then
+ if Nkind (Nxt) = N_Label
+ and then not Restriction_Check_Required (SPARK)
+ then
return;
-- Otherwise see if we have a real statement following us
-- at removing warnings in deleted code, and this is one
-- warning we would prefer NOT to have removed.
- Error_Loc := Sloc (Nxt);
+ Error_Node := Nxt;
-- If we have unreachable code, analyze and remove the
-- unreachable code, since it is useless and we don't
-- Now issue the warning (or error in formal mode)
- if Formal_Verification_Mode then
- Formal_Error_Msg
- ("unreachable code is not allowed", Error_Loc);
+ if Restriction_Check_Required (SPARK) then
+ Check_SPARK_Restriction
+ ("unreachable code is not allowed", Error_Node);
else
- Error_Msg ("?unreachable code!", Error_Loc);
+ Error_Msg ("?unreachable code!", Sloc (Error_Node));
end if;
end if;
- -- If the unconditional transfer of control instruction is
- -- the last statement of a sequence, then see if our parent
- -- is one of the constructs for which we count unblocked exits,
- -- and if so, adjust the count.
+ -- If the unconditional transfer of control instruction is the
+ -- last statement of a sequence, then see if our parent is one of
+ -- the constructs for which we count unblocked exits, and if so,
+ -- adjust the count.
else
P := Parent (N);
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