Minor reformatting.

(Install_Null_Excluding_Check): Moved to the package specification
to use it from other packages to generate the run-time check
associated with the null-exclusion attribute.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@103896 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 109 insertions, 108 deletions

diff --git a/gcc/ada/checks.ads b/gcc/ada/checks.ads
index 5810bcbe4f9..c16495dd1a2 100644
--- a/gcc/ada/checks.ads
+++ b/gcc/ada/checks.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-2004 Free Software Foundation, Inc.          --
+--          Copyright (C) 1992-2005 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- --
@@ -159,16 +159,20 @@ package Checks is
       OK : out Boolean;
       Lo : out Uint;
       Hi : out Uint);
-   --  N is a node for a subexpression. If N is of a discrete type with
-   --  no error indications, and no other peculiarities (e.g. missing
-   --  type fields), then OK is True on return, and Lo and Hi are set
-   --  to a conservative estimate of the possible range of values of N.
-   --  Thus if OK is True on return, the value of the subexpression N is
-   --  known to like in the range Lo .. Hi (inclusive). If the expression
-   --  is not of a discrete type, or some kind of error condition is
-   --  detected, then OK is False on exit, and Lo/Hi are set to No_Uint.
-   --  Thus the significance of OK being False on return is that no
-   --  useful information is available on the range of the expression.
+   --  N is a node for a subexpression. If N is of a discrete type with no
+   --  error indications, and no other peculiarities (e.g. missing type
+   --  fields), then OK is True on return, and Lo and Hi are set to a
+   --  conservative estimate of the possible range of values of N. Thus if OK
+   --  is True on return, the value of the subexpression N is known to like in
+   --  the range Lo .. Hi (inclusive). If the expression is not of a discrete
+   --  type, or some kind of error condition is detected, then OK is False on
+   --  exit, and Lo/Hi are set to No_Uint. Thus the significance of OK being
+   --  False on return is that no useful information is available on the range
+   --  of the expression.
+
+   procedure Install_Null_Excluding_Check (N : Node_Id);
+   --  Determines whether an access node requires a runtime access check and
+   --  if so inserts the appropriate run-time check.
 
    -------------------------------------------------------
    -- Control and Optimization of Range/Overflow Checks --
@@ -181,12 +185,12 @@ package Checks is
    --  in the transitional phase where some of these checks are still done
    --  by the back end, but many are done by the front end.
 
-   --  Overflow checks are similarly controlled by the Do_Overflow_Check
-   --  flag. The difference here is that if Backend_Overflow_Checks is
-   --  is (Backend_Overflow_Checks_On_Target set False), then the actual
-   --  overflow checks are generated by the front end, but if back end
-   --  overflow checks are active (Backend_Overflow_Checks_On_Target
-   --  set True), then the back end does generate the checks.
+   --  Overflow checks are similarly controlled by the Do_Overflow_Check flag.
+   --  The difference here is that if Backend_Overflow_Checks is is
+   --  (Backend_Overflow_Checks_On_Target set False), then the actual overflow
+   --  checks are generated by the front end, but if back end overflow checks
+   --  are active (Backend_Overflow_Checks_On_Target set True), then the back
+   --  end does generate the checks.
 
    --  The following two routines are used to set these flags, they allow
    --  for the possibility of eliminating checks. Checks can be eliminated
@@ -266,17 +270,16 @@ package Checks is
 
    --  The checks operate in one of two modes:
 
-   --    If Source_Typ is Empty, then the node Expr is examined, at the
-   --    very least to get the source subtype. In addition for some of
-   --    the checks, the actual form of the node may be examined. For
-   --    example, a node of type Integer whose actual form is an Integer
-   --    conversion from a type with range 0 .. 3 can be determined to
-   --    have a value in the range 0 .. 3.
+   --    If Source_Typ is Empty, then the node Expr is examined, at the very
+   --    least to get the source subtype. In addition for some of the checks,
+   --    the actual form of the node may be examined. For example, a node of
+   --    type Integer whose actual form is an Integer conversion from a type
+   --    with range 0 .. 3 can be determined to have a value in range 0 .. 3.
 
-   --    If Source_Typ is given, then nothing can be assumed about the
-   --    Expr, and indeed its contents are not examined. In this case the
-   --    check is based on the assumption that Expr can be an arbitrary
-   --    value of the given Source_Typ.
+   --    If Source_Typ is given, then nothing can be assumed about the Expr,
+   --    and indeed its contents are not examined. In this case the check is
+   --    based on the assumption that Expr can be an arbitrary value of the
+   --    given Source_Typ.
 
    --  Currently, the only case in which a Source_Typ is explicitly supplied
    --  is for the case of Out and In_Out parameters, where, for the conversion
@@ -293,8 +296,8 @@ package Checks is
    --  to Insert_Actions.
    --
    --  For access types, the Directly_Designated_Type is retrieved and
-   --  processing continues as enumerated above, with a guard against
-   --  null values.
+   --  processing continues as enumerated above, with a guard against null
+   --  values.
    --
    --  Note: calls to Apply_Length_Check currently never supply an explicit
    --  Source_Typ parameter, but Apply_Length_Check takes this parameter and
@@ -305,9 +308,9 @@ package Checks is
      (Ck_Node    : Node_Id;
       Target_Typ : Entity_Id;
       Source_Typ : Entity_Id := Empty);
-   --  For an Node of kind N_Range, constructs a range check action that
-   --  tests first that the range is not null and then that the range
-   --  is contained in the Target_Typ range.
+   --  For an Node of kind N_Range, constructs a range check action that tests
+   --  first that the range is not null and then that the range is contained in
+   --  the Target_Typ range.
    --
    --  For scalar types, constructs a range check action that first tests that
    --  the expression is contained in the Target_Typ range. The difference
@@ -318,13 +321,13 @@ package Checks is
    --  to check that each Expr range is properly contained in the range of
    --  Target_Typ.
    --
-   --  For a type conversion to an unconstrained array type, constructs
-   --  a range check action to check that the bounds of the source type
-   --  are within the constraints imposed by the Target_Typ.
+   --  For a type conversion to an unconstrained array type, constructs a range
+   --  check action to check that the bounds of the source type are within the
+   --  constraints imposed by the Target_Typ.
    --
    --  For access types, the Directly_Designated_Type is retrieved and
-   --  processing continues as enumerated above, with a guard against
-   --  null values.
+   --  processing continues as enumerated above, with a guard against null
+   --  values.
    --
    --  The source type is used by type conversions to unconstrained array
    --  types to retrieve the corresponding bounds.
@@ -344,10 +347,10 @@ package Checks is
       Source_Typ : Entity_Id := Empty;
       Fixed_Int  : Boolean   := False);
    --  For scalar types, determines whether an expression node should be
-   --  flagged as needing a runtime range check. If the node requires such
-   --  a check, the Do_Range_Check flag is turned on. The Fixed_Int flag
-   --  if set causes any fixed-point values to be treated as though they
-   --  were discrete values (i.e. the underlying integer value is used).
+   --  flagged as needing a runtime range check. If the node requires such a
+   --  check, the Do_Range_Check flag is turned on. The Fixed_Int flag if set
+   --  causes any fixed-point values to be treated as though they were discrete
+   --  values (i.e. the underlying integer value is used).
 
    type Check_Result is private;
    --  Type used to return result of Range_Check call, for later use in
@@ -360,12 +363,11 @@ package Checks is
       Static_Sloc  : Source_Ptr;
       Flag_Node    : Node_Id);
    --  Called to append range checks as returned by a call to Range_Check.
-   --  Stmts is a list to which either the dynamic check is appended or
-   --  the raise Constraint_Error statement is appended (for static checks).
-   --  Static_Sloc is the Sloc at which the raise CE node points,
-   --  Flag_Node is used as the node at which to set the Has_Dynamic_Check
-   --  flag. Checks_On is a boolean value that says if range and index checking
-   --  is on or not.
+   --  Stmts is a list to which either the dynamic check is appended or the
+   --  raise Constraint_Error statement is appended (for static checks).
+   --  Static_Sloc is the Sloc at which the raise CE node points, Flag_Node is
+   --  used as the node at which to set the Has_Dynamic_Check flag. Checks_On
+   --  is a boolean value that says if range and index checking is on or not.
 
    procedure Insert_Range_Checks
      (Checks       : Check_Result;
@@ -402,12 +404,12 @@ package Checks is
    -- Expander Routines --
    -----------------------
 
-   --  Some of the earlier processing for checks results in temporarily
-   --  setting the Do_Range_Check flag rather than actually generating
-   --  checks. Now we are moving the generation of such checks into the
-   --  front end for reasons of efficiency and simplicity (there were
-   --  difficutlies in handling this in the back end when side effects
-   --  were present in the expressions being checked).
+   --  Some of the earlier processing for checks results in temporarily setting
+   --  the Do_Range_Check flag rather than actually generating checks. Now we
+   --  are moving the generation of such checks into the front end for reasons
+   --  of efficiency and simplicity (there were difficutlies in handling this
+   --  in the back end when side effects were present in the expressions being
+   --  checked).
 
    --  Probably we could eliminate the Do_Range_Check flag entirely and
    --  generate the checks earlier, but this is a delicate area and it
@@ -419,37 +421,36 @@ package Checks is
      (N           : Node_Id;
       Target_Type : Entity_Id;
       Reason      : RT_Exception_Code);
-   --  This procedure is called to actually generate and insert a range
-   --  check. A check is generated to ensure that the value of N lies
-   --  within the range of the target type. Note that the base type of
-   --  N may be different from the base type of the target type. This
-   --  happens in the conversion case. The Reason parameter is the
-   --  exception code to be used for the exception if raised.
+   --  This procedure is called to actually generate and insert a range check.
+   --  A check is generated to ensure that the value of N lies within the range
+   --  of the target type. Note that the base type of N may be different from
+   --  the base type of the target type. This happens in the conversion case.
+   --  The Reason parameter is the exception code to be used for the exception
+   --  if raised.
    --
-   --  Note on the relation of this routine to the Do_Range_Check flag.
-   --  Mostly for historical reasons, we often set the Do_Range_Check
-   --  flag and then later we call Generate_Range_Check if this flag is
-   --  set. Most probably we could eliminate this intermediate setting
-   --  of the flag (historically the back end dealt with range checks,
-   --  using this flag to indicate if a check was required, then we
-   --  moved checks into the front end).
+   --  Note on the relation of this routine to the Do_Range_Check flag. Mostly
+   --  for historical reasons, we often set the Do_Range_Check flag and then
+   --  later we call Generate_Range_Check if this flag is set. Most probably we
+   --  could eliminate this intermediate setting of the flag (historically the
+   --  back end dealt with range checks, using this flag to indicate if a check
+   --  was required, then we moved checks into the front end).
 
    procedure Generate_Index_Checks (N : Node_Id);
-   --  This procedure is called to generate index checks on the subscripts
-   --  for the indexed component node N. Each subscript expression is
-   --  examined, and if the Do_Range_Check flag is set, an appropriate
-   --  index check is generated and the flag is reset.
+   --  This procedure is called to generate index checks on the subscripts for
+   --  the indexed component node N. Each subscript expression is examined, and
+   --  if the Do_Range_Check flag is set, an appropriate index check is
+   --  generated and the flag is reset.
 
    --  Similarly, we set the flag Do_Discriminant_Check in the semantic
-   --  analysis to indicate that a discriminant check is required for a
-   --  selected component of a discriminated type. The following routine
-   --  is called from the expander to actually generate the call.
+   --  analysis to indicate that a discriminant check is required for selected
+   --  component of a discriminated type. The following routine is called from
+   --  the expander to actually generate the call.
 
    procedure Generate_Discriminant_Check (N : Node_Id);
-   --  N is a selected component for which a discriminant check is required
-   --  to make sure that the discriminants have appropriate values for the
-   --  selection. This is done by calling the appropriate discriminant
-   --  checking routine for the selector.
+   --  N is a selected component for which a discriminant check is required to
+   --  make sure that the discriminants have appropriate values for the
+   --  selection. This is done by calling the appropriate discriminant checking
+   --  routine for the selector.
 
    -----------------------
    -- Validity Checking --
@@ -457,15 +458,15 @@ package Checks is
 
    --  In (RM 13.9.1(9-11)) we have the following rules on invalid values
 
-   --    If the representation of a scalar object does not represent a
-   --    value of the object's subtype (perhaps because the object was not
-   --    initialized), the object is said to have an invalid representation.
-   --    It is a bounded error to evaluate the value of such an object.  If
-   --    the error is detected, either Constraint_Error or Program_Error is
-   --    raised.  Otherwise, execution continues using the invalid
-   --    representation.  The rules of the language outside this subclause
-   --    assume that all objects have valid representations.  The semantics
-   --    of operations on invalid representations are as follows:
+   --    If the representation of a scalar object does not represent value of
+   --    the object's subtype (perhaps because the object was not initialized),
+   --    the object is said to have an invalid representation. It is a bounded
+   --    error to evaluate the value of such an object. If the error is
+   --    detected, either Constraint_Error or Program_Error is raised.
+   --    Otherwise, execution continues using the invalid representation. The
+   --    rules of the language outside this subclause assume that all objects
+   --    have valid representations. The semantics of operations on invalid
+   --    representations are as follows:
    --
    --       10  If the representation of the object represents a value of the
    --           object's type, the value of the type is used.
@@ -483,9 +484,9 @@ package Checks is
    --  array assignments, where we don't want to do wild stores, and case
    --  statements where we don't want to do wild jumps.
 
-   --  In GNAT, we control validity checking with a switch -gnatV that
-   --  can take three parameters, n/d/f for None/Default/Full. These
-   --  modes have the following meanings:
+   --  In GNAT, we control validity checking with a switch -gnatV that can take
+   --  three parameters, n/d/f for None/Default/Full. These modes have the
+   --  following meanings:
 
    --    None (no validity checking)
 
@@ -577,12 +578,12 @@ package Checks is
    --  are checked for validity.
 
    procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id);
-   --  Expr is a lvalue, i.e. an expression representing the target of
-   --  an assignment. This procedure checks for this expression involving
-   --  an assignment to an array value. We have to be sure that all the
-   --  subscripts in such a case are valid, since according to the rules
-   --  in (RM 13.9.1(9-11)) such assignments are not permitted to result
-   --  in erroneous behavior in the case of invalid subscript values.
+   --  Expr is a lvalue, i.e. an expression representing the target of an
+   --  assignment. This procedure checks for this expression involving an
+   --  assignment to an array value. We have to be sure that all the subscripts
+   --  in such a case are valid, since according to the rules in (RM
+   --  13.9.1(9-11)) such assignments are not permitted to result in erroneous
+   --  behavior in the case of invalid subscript values.
 
    procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False);
    --  Ensure that Expr represents a valid value of its type. If this type
@@ -602,14 +603,14 @@ package Checks is
    --  valid, raising Constraint_Error if the value is not valid.
 
    function Expr_Known_Valid (Expr : Node_Id) return Boolean;
-   --  This function tests it the value of Expr is known to be valid in
-   --  the sense of RM 13.9.1(9-11). In the case of GNAT, it is only
-   --  discrete types which are a concern, since for non-discrete types
-   --  we simply continue computation with invalid values, which does
-   --  not lead to erroneous behavior. Thus Expr_Known_Valid always
-   --  returns True if the type of Expr is non-discrete. For discrete
-   --  types the value returned is True only if it can be determined
-   --  that the value is Valid. Otherwise False is returned.
+   --  This function tests it the value of Expr is known to be valid in the
+   --  sense of RM 13.9.1(9-11). In the case of GNAT, it is only discrete types
+   --  which are a concern, since for non-discrete types we simply continue
+   --  computation with invalid values, which does not lead to erroneous
+   --  behavior. Thus Expr_Known_Valid always returns True if the type of Expr
+   --  is non-discrete. For discrete types the value returned is True only if
+   --  it can be determined that the value is Valid. Otherwise False is
+   --  returned.
 
    procedure Insert_Valid_Check (Expr : Node_Id);
    --  Inserts code that will check for the value of Expr being valid, in
@@ -635,12 +636,12 @@ private
    --    responsibility of the caller to rewrite and substitute the nodes with
    --    N_Raise_Constraint_Error nodes.
    --
-   --    For the non-static case a single N_Raise_Constraint_Error node
-   --    with a non-empty Condition field is returned.
+   --    For the non-static case a single N_Raise_Constraint_Error node with a
+   --    non-empty Condition field is returned.
    --
-   --  Unused entries in Check_Result, if any, are simply set to Empty
-   --  For external clients, the required processing on this result is
-   --  achieved using the Insert_Range_Checks routine.
+   --  Unused entries in Check_Result, if any, are simply set to Empty For
+   --  external clients, the required processing on this result is achieved
+   --  using the Insert_Range_Checks routine.
 
    pragma Inline (Apply_Length_Check);
    pragma Inline (Apply_Range_Check);