-- --
-- S p e c --
-- --
--- Copyright (C) 1996-2005, Free Software Foundation, Inc. --
+-- Copyright (C) 1996-2006, 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- --
-- as described in Namet). Upper case letters are used only for entities
-- generated by the compiler.
- -- There are two cases, global entities, and local entities. In more
- -- formal terms, local entities are those which have a dynamic enclosing
- -- scope, and global entities are at the library level, except that we
- -- always consider procedures to be global entities, even if they are
- -- nested (that's because at the debugger level a procedure name refers
- -- to the code, and the code is indeed a global entity, including the
- -- case of nested procedures.) In addition, we also consider all types
- -- to be global entities, even if they are defined within a procedure.
+ -- There are two cases, global entities, and local entities. In more formal
+ -- terms, local entities are those which have a dynamic enclosing scope,
+ -- and global entities are at the library level, except that we always
+ -- consider procedures to be global entities, even if they are nested
+ -- (that's because at the debugger level a procedure name refers to the
+ -- code, and the code is indeed a global entity, including the case of
+ -- nested procedures.) In addition, we also consider all types to be global
+ -- entities, even if they are defined within a procedure.
- -- The reason for treating all type names as global entities is that
- -- a number of our type encodings work by having related type names,
- -- and we need the full qualification to keep this unique.
+ -- The reason for treating all type names as global entities is that a
+ -- number of our type encodings work by having related type names, and we
+ -- need the full qualification to keep this unique.
-- For global entities, the encoded name includes all components of the
-- fully expanded name (but omitting Standard at the start). For example,
-- there is an entity in this embdded package whose name is S, the encoded
-- name will include the components p.q.r.s.
- -- For local entities, the encoded name only includes the components
- -- up to the enclosing dynamic scope (other than a block). At run time,
- -- such a dynamic scope is a subprogram, and the debugging formats know
- -- about local variables of procedures, so it is not necessary to have
- -- full qualification for such entities. In particular this means that
- -- direct local variables of a procedure are not qualified.
+ -- For local entities, the encoded name only includes the components up to
+ -- the enclosing dynamic scope (other than a block). At run time, such a
+ -- dynamic scope is a subprogram, and the debugging formats know about
+ -- local variables of procedures, so it is not necessary to have full
+ -- qualification for such entities. In particular this means that direct
+ -- local variables of a procedure are not qualified.
-- As an example of the local name convention, consider a procedure V.W
- -- with a local variable X, and a nested block Y containing an entity
- -- Z. The fully qualified names of the entities X and Z are:
+ -- with a local variable X, and a nested block Y containing an entity Z.
+ -- The fully qualified names of the entities X and Z are:
-- V.W.X
-- V.W.Y.Z
-- Handling of Overloading --
-----------------------------
- -- The above scheme is incomplete with respect to overloaded
- -- subprograms, since overloading can legitimately result in a
- -- case of two entities with exactly the same fully qualified names.
- -- To distinguish between entries in a set of overloaded subprograms,
- -- the encoded names are serialized by adding the suffix:
+ -- The above scheme is incomplete for overloaded subprograms, since
+ -- overloading can legitimately result in case of two entities with
+ -- exactly the same fully qualified names. To distinguish between
+ -- entries in a set of overloaded subprograms, the encoded names are
+ -- serialized by adding the suffix:
-- __nn (two underscores)
-- 3 for the third, etc.). A suffix of __1 is always omitted (i.e. no
-- suffix implies the first instance).
- -- These names are prefixed by the normal full qualification. So
- -- for example, the third instance of the subprogram qrs in package
- -- yz would have the name:
+ -- These names are prefixed by the normal full qualification. So for
+ -- example, the third instance of the subprogram qrs in package yz
+ -- would have the name:
-- yz__qrs__3
-- __nn_nn_nn ...
- -- where the nn values are the homonym numbers as needed for any of
- -- the qualifying entities, separated by a single underscore. If all
- -- the nn values are 1, the suffix is omitted, Otherwise the suffix
- -- is present (including any values of 1). The following example
- -- shows how this suffixing works.
+ -- where the nn values are the homonym numbers as needed for any of the
+ -- qualifying entities, separated by a single underscore. If all the nn
+ -- values are 1, the suffix is omitted, Otherwise the suffix is present
+ -- (including any values of 1). The following example shows how this
+ -- suffixing works.
-- package body Yz is
-- procedure Qrs is -- Name is yz__qrs
-- Operator Names --
--------------------
- -- The above rules applied to operator names would result in names
- -- with quotation marks, which are not typically allowed by assemblers
- -- and linkers, and even if allowed would be odd and hard to deal with.
- -- To avoid this problem, operator names are encoded as follows:
+ -- The above rules applied to operator names would result in names with
+ -- quotation marks, which are not typically allowed by assemblers and
+ -- linkers, and even if allowed would be odd and hard to deal with. To
+ -- avoid this problem, operator names are encoded as follows:
-- Oabs abs
-- Oand and
-- These names are prefixed by the normal full qualification, and
-- suffixed by the overloading identification. So for example, the
- -- second operator "=" defined in package Extra.Messages would
- -- have the name:
+ -- second operator "=" defined in package Extra.Messages would have
+ -- the name:
-- extra__messages__Oeq__2
----------------------------------
-- It might be thought that the above scheme is complete, but in Ada 95,
- -- full qualification is insufficient to uniquely identify an entity
- -- in the program, even if it is not an overloaded subprogram. There
- -- are two possible confusions:
+ -- full qualification is insufficient to uniquely identify an entity in
+ -- the program, even if it is not an overloaded subprogram. There are
+ -- two possible confusions:
-- a.b
-- interpretation 1: entity c in child package a.b
-- interpretation 2: entity c in nested package b in body of a
- -- It is perfectly legal in both cases for both interpretations to
- -- be valid within a single program. This is a bit of a surprise since
+ -- It is perfectly legal in both cases for both interpretations to be
+ -- valid within a single program. This is a bit of a surprise since
-- certainly in Ada 83, full qualification was sufficient, but not in
-- Ada 95. The result is that the above scheme can result in duplicate
-- names. This would not be so bad if the effect were just restricted
-- a real problem of name clashes.
-- To deal with this situation, we provide two additional encoding
- -- rules for names
+ -- rules for names:
-- First: all library subprogram names are preceded by the string
-- _ada_ (which causes no duplications, since normal Ada names can
-- Base Record Types --
-----------------------
- -- Under certain circumstances, debuggers need two descriptions
- -- of a record type, one that gives the actual details of the
- -- base type's structure (as described elsewhere in these
- -- comments) and one that may be used to obtain information
- -- about the particular subtype and the size of the objects
- -- being typed. In such cases the compiler will substitute a
- -- type whose name is typically compiler-generated and
+ -- Under certain circumstances, debuggers need two descriptions of a
+ -- record type, one that gives the actual details of the base type's
+ -- structure (as described elsewhere in these comments) and one that may
+ -- be used to obtain information about the particular subtype and the
+ -- size of the objects being typed. In such cases the compiler will
+ -- substitute type whose name is typically compiler-generated and
-- irrelevant except as a key for obtaining the actual type.
- -- Specifically, if this name is x, then we produce a record
- -- type named x___XVS consisting of one field. The name of
- -- this field is that of the actual type being encoded, which
- -- we'll call y (the type of this single field is arbitrary).
- -- Both x and y may have corresponding ___XVE types.
-
- -- The size of the objects typed as x should be obtained from
- -- the structure of x (and x___XVE, if applicable) as for
- -- ordinary types unless there is a variable named x___XVZ, which,
- -- if present, will hold the the size (in bits) of x.
-
- -- The type x will either be a subtype of y (see also Subtypes
- -- of Variant Records, below) or will contain no fields at
- -- all. The layout, types, and positions of these fields will
- -- be accurate, if present. (Currently, however, the GDB
- -- debugger makes no use of x except to determine its size).
+
+ -- Specifically, if this name is x, then we produce a record type named
+ -- x___XVS consisting of one field. The name of this field is that of
+ -- the actual type being encoded, which we'll call y (the type of this
+ -- single field is arbitrary). Both x and y may have corresponding
+ -- ___XVE types.
+
+ -- The size of the objects typed as x should be obtained from the
+ -- structure of x (and x___XVE, if applicable) as for ordinary types
+ -- unless there is a variable named x___XVZ, which, if present, will
+ -- hold the the size (in bits) of x.
+
+ -- The type x will either be a subtype of y (see also Subtypes of
+ -- Variant Records, below) or will contain no fields at all. The layout,
+ -- types, and positions of these fields will be accurate, if present.
+ -- (Currently, however, the GDB debugger makes no use of x except to
+ -- determine its size).
-- Among other uses, XVS types are sometimes used to encode
-- unconstrained types. For example, given
--
-- at1___C_PAD___XVZ: constant Integer := 32 + M * 8 + padding term;
--
- -- Not all unconstrained types are so encoded; the XVS
- -- convention may be unnecessary for unconstrained types of
- -- fixed size. However, this encoding is always necessary when
- -- a subcomponent type (array element's type or record field's
- -- type) is an unconstrained record type some of whose
- -- components depend on discriminant values.
+ -- Not all unconstrained types are so encoded; the XVS convention may be
+ -- unnecessary for unconstrained types of fixed size. However, this
+ -- encoding is always necessary when a subcomponent type (array
+ -- element's type or record field's type) is an unconstrained record
+ -- type some of whose components depend on discriminant values.
-----------------
-- Array Types --
-- are the names of the types for the bounds. The types of these
-- fields is an integer type which is meaningless.
- -- To conserve space, we do not produce this type unless one of
- -- the index types is either an enumeration type, has a variable
- -- upper bound, has a lower bound different from the constant 1,
- -- is a biased type, or is wider than "sizetype".
+ -- To conserve space, we do not produce this type unless one of the
+ -- index types is either an enumeration type, has a variable upper
+ -- bound, has a lower bound different from the constant 1, is a biased
+ -- type, or is wider than "sizetype".
-- Given the full encoding of these types (see above description for
-- the encoding of discrete types), this means that all necessary
- -- information for addressing arrays is available. In some
- -- debugging formats, some or all of the bounds information may
- -- be available redundantly, particularly in the fixed-point case,
- -- but this information can in any case be ignored by the debugger.
+ -- information for addressing arrays is available. In some debugging
+ -- formats, some or all of the bounds information may be available
+ -- redundantly, particularly in the fixed-point case, but this
+ -- information can in any case be ignored by the debugger.
----------------------------
-- Note on Implicit Types --
----------------------------
- -- The compiler creates implicit type names in many situations where
- -- a type is present semantically, but no specific name is present.
- -- For example:
+ -- The compiler creates implicit type names in many situations where a
+ -- type is present semantically, but no specific name is present. For
+ -- example:
-- S : Integer range M .. N;
- -- Here the subtype of S is not integer, but rather an anonymous
- -- subtype of Integer. Where possible, the compiler generates names
- -- for such anonymous types that are related to the type from which
- -- the subtype is obtained as follows:
+ -- Here the subtype of S is not integer, but rather an anonymous subtype
+ -- of Integer. Where possible, the compiler generates names for such
+ -- anonymous types that are related to the type from which the subtype
+ -- is obtained as follows:
-- T name suffix
-- where name is the name from which the subtype is obtained, using
-- lower case letters and underscores, and suffix starts with an upper
- -- case letter. For example, the name for the above declaration of S
- -- might be:
+ -- case letter. For example the name for the above declaration might be:
-- TintegerS4b
-- x___XRE for an exception renaming
-- x___XRP for a package renaming
- -- The name is fully qualified in the usual manner, i.e. qualified in
- -- the same manner as the entity x would be. In the case of a package
- -- renaming where x is a child unit, the qualification includes the
- -- name of the parent unit, to disambiguate child units with the same
- -- simple name and (of necessity) different parents.
+ -- The name is fully qualified in the usual manner, i.e. qualified in the
+ -- same manner as the entity x would be. In the case of a package renaming
+ -- where x is a child unit, the qualification includes the name of the
+ -- parent unit, to disambiguate child units with the same simple name and
+ -- (of necessity) different parents.
-- Note: subprogram renamings are not encoded at the present time
-- (y___XE)
- -- i.e. the enumeration type has a single field, whose name
- -- matches the name y, with the XE suffix. The entity for this
- -- enumeration literal is fully qualified in the usual manner.
- -- All subprogram, exception, and package renamings fall into
- -- this category, as well as simple object renamings.
+ -- i.e. the enumeration type has a single field, whose name matches
+ -- the name y, with the XE suffix. The entity for this enumeration
+ -- literal is fully qualified in the usual manner. All subprogram,
+ -- exception, and package renamings fall into this category, as
+ -- well as simple object renamings.
-- For the object renaming case where y is a selected component or an
-- indexed component, the literal name is suffixed by additional fields
- -- that give details of the components. The name starts as above with
- -- a y___XE entity indicating the outer level variable. Then a series
- -- of selections and indexing operations can be specified as follows:
+ -- that give details of the components. The name starts as above with a
+ -- y___XE entity indicating the outer level variable. Then a series of
+ -- selections and indexing operations can be specified as follows:
-- Indexed component
-- Slice
- -- For the slice case, we have two entries. The first is for
- -- the lower bound of the slice, and has the form
+ -- For the slice case, we have two entries. The first is for the
+ -- lower bound of the slice, and has the form
-- XLnnn
-- XLe
- -- Specifies the lower bound, using exactly the same encoding
- -- as for an XS subscript as described above.
+ -- Specifies the lower bound, using exactly the same encoding as
+ -- for an XS subscript as described above.
-- Then the upper bound appears in the usual XSnnn/XSe form
-- BV(0) BV(1) BV(2) BV(3) BV(4) BV(5) unused bits
-- Note that if a modular type is used to represent the array, the
- -- allocation in memory is not the same as a normal modular type.
- -- The difference occurs when the allocated object is larger than
- -- the size of the array. For a normal modular type, we extend the
- -- value on the left with zeroes.
-
- -- For example, in the normal modular case, if we have a 6-bit
- -- modular type, declared as mod 2**6, and we allocate an 8-bit
- -- object for this type, then we extend the value with two bits
- -- on the most significant end, and in either the little-endian
- -- or big-endian case, the value 63 is represented as 00111111
- -- in binary in memory.
+ -- allocation in memory is not the same as a normal modular type. The
+ -- difference occurs when the allocated object is larger than the size of
+ -- the array. For a normal modular type, we extend the value on the left
+ -- with zeroes.
+
+ -- For example, in the normal modular case, if we have a 6-bit modular
+ -- type, declared as mod 2**6, and we allocate an 8-bit object for this
+ -- type, then we extend the value with two bits on the most significant
+ -- end, and in either the little-endian or big-endian case, the value 63 is
+ -- represented as 00111111 in binary in memory.
-- For a modular type used to represent a packed array, the rule is
- -- different. In this case, if we have to extend the value, then we
- -- do it with undefined bits (which are not initialized and whose value
- -- is irrelevant to any generated code). Furthermore these bits are on
- -- the right (least significant bits) in the big-endian case, and on the
- -- left (most significant bits) in the little-endian case.
+ -- different. In this case, if we have to extend the value, then we do it
+ -- with undefined bits (which are not initialized and whose value is
+ -- irrelevant to any generated code). Furthermore these bits are on the
+ -- right (least significant bits) in the big-endian case, and on the left
+ -- (most significant bits) in the little-endian case.
- -- For example, if we have a packed boolean array of 6 bits, all set
- -- to True, stored in an 8-bit object, then the value in memory in
- -- binary is ??111111 in the little-endian case, and 111111?? in the
- -- big-endian case.
+ -- For example, if we have a packed boolean array of 6 bits, all set to
+ -- True, stored in an 8-bit object, then the value in memory in binary is
+ -- ??111111 in the little-endian case, and 111111?? in the big-endian case.
-- This is done so that the representation of packed arrays does not
-- depend on whether we use a modular representation or array of bytes
- -- as previously described. This ensures that we can pass such values
- -- by reference in the case where a subprogram has to be able to handle
- -- values stored in either form.
+ -- as previously described. This ensures that we can pass such values by
+ -- reference in the case where a subprogram has to be able to handle values
+ -- stored in either form.
- -- Note that when we extract the value of such a modular packed array,
- -- we expect to retrieve only the relevant bits, so in this same example,
- -- when we extract the value, we get 111111 in both cases, and the code
- -- generated by the front end assumes this, although it does not assume
- -- that any high order bits are defined.
+ -- Note that when we extract the value of such a modular packed array, we
+ -- expect to retrieve only the relevant bits, so in this same example, when
+ -- we extract the value we get 111111 in both cases, and the code generated
+ -- by the front end assumes this although it does not assume that any high
+ -- order bits are defined.
- -- There are opportunities for optimization based on the knowledge that
- -- the unused bits are irrelevant for these type of packed arrays. For
- -- example if we have two such 6-bit-in-8-bit values and we do an
- -- assignment:
+ -- There are opportunities for optimization based on the knowledge that the
+ -- unused bits are irrelevant for these type of packed arrays. For example
+ -- if we have two such 6-bit-in-8-bit values and we do an assignment:
-- a := b;
-- Then logically, we extract the 6 bits and store only 6 bits in the
- -- result, but the back end is free to simply assign the entire 8-bits
- -- in this case, since we don't actually care about the undefined bits.
+ -- result, but the back end is free to simply assign the entire 8-bits in
+ -- this case, since we don't actually care about the undefined bits.
-- However, in the equality case, it is important to ensure that the
-- undefined bits do not participate in an equality test.
-- If a modular packed array value is assigned to a register, then
- -- logically it could always be held right justified, to avoid any
- -- need to shift, e.g. when doing comparisons. But probably this is
- -- a bad choice, as it would mean that an assignment such as a := b
- -- above would require shifts when one value is in a register and the
- -- other value is in memory.
+ -- logically it could always be held right justified, to avoid any need to
+ -- shift, e.g. when doing comparisons. But probably this is a bad choice,
+ -- as it would mean that an assignment such as a := above would require
+ -- shifts when one value is in a register and the other value is in memory.
------------------------------------------------------
-- Subprograms for Handling Packed Array Type Names --
(Typ : Entity_Id;
Csize : Uint)
return Name_Id;
- -- This function is used in Exp_Pakd to create the name that is encoded
- -- as described above. The entity Typ provides the name ttt, and the
- -- value Csize is the component size that provides the nnn value.
+ -- This function is used in Exp_Pakd to create the name that is encoded as
+ -- described above. The entity Typ provides the name ttt, and the value
+ -- Csize is the component size that provides the nnn value.
--------------------------------------
-- Pointers to Unconstrained Arrays --
--------------------------------------
- -- There are two kinds of pointers to arrays. The debugger can tell
- -- which format is in use by the form of the type of the pointer.
+ -- There are two kinds of pointers to arrays. The debugger can tell which
+ -- format is in use by the form of the type of the pointer.
-- Fat Pointers
-- Fat pointers are represented as a struct with two fields. This
-- struct has two distinguished field names:
- -- P_ARRAY is a pointer to the array type. The name of this
- -- type is the unconstrained type followed by "___XUA". This
- -- array will have bounds which are the discriminants, and
- -- hence are unparsable, but will give the number of
- -- subscripts and the component type.
+ -- P_ARRAY is a pointer to the array type. The name of this type is
+ -- the unconstrained type followed by "___XUA". This array will have
+ -- bounds which are the discriminants, and hence are unparsable, but
+ -- will give the number of subscripts and the component type.
-- P_BOUNDS is a pointer to a struct, the name of whose type is the
-- unconstrained array name followed by "___XUB" and which has
-- LBn (n a decimal integer) lower bound of n'th dimension
-- UBn (n a decimal integer) upper bound of n'th dimension
- -- The bounds may be any integral type. In the case of an
- -- enumeration type, Enum_Rep values are used.
+ -- The bounds may be any integral type. In the case of an enumeration
+ -- type, Enum_Rep values are used.
- -- The debugging information will sometimes reference an anonymous
- -- fat pointer type. Such types are given the name xxx___XUP, where
- -- xxx is the name of the designated type. If the debugger is asked
- -- to output such a type name, the appropriate form is "access xxx".
+ -- The debugging information will sometimes reference an anonymous fat
+ -- pointer type. Such types are given the name xxx___XUP, where xxx is
+ -- the name of the designated type. If the debugger is asked to output
+ -- such a type name, the appropriate form is "access xxx".
-- Thin Pointers
- -- The value of a thin pointer is a pointer to the second field
- -- of a structure with two fields. The name of this structure's
- -- type is "arr___XUT", where "arr" is the name of the
- -- unconstrained array type. Even though it actually points into
- -- middle of this structure, the thin pointer's type in debugging
- -- information is pointer-to-arr___XUT.
-
- -- The first field of arr___XUT is named BOUNDS, and has a type
- -- named arr___XUB, with the structure described for such types
- -- in fat pointers, as described above.
-
- -- The second field of arr___XUT is named ARRAY, and contains
- -- the actual array. Because this array has a dynamic size,
- -- determined by the BOUNDS field that precedes it, all of the
- -- information about arr___XUT is encoded in a parallel type named
- -- arr___XUT___XVE, with fields BOUNDS and ARRAY___XVL. As for
- -- previously described ___XVE types, ARRAY___XVL has
- -- a pointer-to-array type. However, the array type in this case
- -- is named arr___XUA and only its element type is meaningful,
- -- just as described for fat pointers.
+ -- The value of a thin pointer is a pointer to the second field of a
+ -- structure with two fields. The name of this structure's type is
+ -- "arr___XUT", where "arr" is the name of the unconstrained array
+ -- type. Even though it actually points into middle of this structure,
+ -- the thin pointer's type in debugging information is
+ -- pointer-to-arr___XUT.
+
+ -- The first field of arr___XUT is named BOUNDS, and has a type named
+ -- arr___XUB, with the structure described for such types in fat
+ -- pointers, as described above.
+
+ -- The second field of arr___XUT is named ARRAY, and contains the
+ -- actual array. Because this array has a dynamic size, determined by
+ -- the BOUNDS field that precedes it, all of the information about
+ -- arr___XUT is encoded in a parallel type named arr___XUT___XVE, with
+ -- fields BOUNDS and ARRAY___XVL. As for previously described ___XVE
+ -- types, ARRAY___XVL has a pointer-to-array type. However, the array
+ -- type in this case is named arr___XUA and only its element type is
+ -- meaningful, just as described for fat pointers.
--------------------------------------
-- Tagged Types and Type Extensions --
--------------------------------------
- -- A type C derived from a tagged type P has a field named "_parent"
- -- of type P that contains its inherited fields. The type of this
- -- field is usually P (encoded as usual if it has a dynamic size),
- -- but may be a more distant ancestor, if P is a null extension of
- -- that type.
+ -- A type C derived from a tagged type P has a field named "_parent" of
+ -- type P that contains its inherited fields. The type of this field is
+ -- usually P (encoded as usual if it has a dynamic size), but may be a more
+ -- distant ancestor, if P is a null extension of that type.
- -- The type tag of a tagged type is a field named _tag, of type void*.
- -- If the type is derived from another tagged type, its _tag field is
- -- found in its _parent field.
+ -- The type tag of a tagged type is a field named _tag, of type void*. If
+ -- the type is derived from another tagged type, its _tag field is found in
+ -- its _parent field.
-----------------------------
-- Variant Record Encoding --
-----------------------------
- -- The variant part of a variant record is encoded as a single field
- -- in the enclosing record, whose name is:
+ -- The variant part of a variant record is encoded as a single field in the
+ -- enclosing record, whose name is:
-- discrim___XVN
- -- where discrim is the unqualified name of the variant. This field name
- -- is built by gigi (not by code in this unit). In the case of an
- -- Unchecked_Union record, this discriminant will not appear in the
- -- record, and the debugger must proceed accordingly (basically it
- -- can treat this case as it would a C union).
-
- -- The type corresponding to this field has a name that is obtained
- -- by concatenating the type name with the above string and is similar
- -- to a C union, in which each member of the union corresponds to one
- -- variant. However, unlike a C union, the size of the type may be
- -- variable even if each of the components are fixed size, since it
- -- includes a computation of which variant is present. In that case,
- -- it will be encoded as above and a type with the suffix "___XVN___XVU"
- -- will be present.
+ -- where discrim is the unqualified name of the variant. This field name is
+ -- built by gigi (not by code in this unit). For Unchecked_Union record,
+ -- this discriminant will not appear in the record, and the debugger must
+ -- proceed accordingly (basically it can treat this case as it would a C
+ -- union).
+
+ -- The type corresponding to this field has a name that is obtained by
+ -- concatenating the type name with the above string and is similar to a C
+ -- union, in which each member of the union corresponds to one variant.
+ -- However, unlike a C union, the size of the type may be variable even if
+ -- each of the components are fixed size, since it includes a computation
+ -- of which variant is present. In that case, it will be encoded as above
+ -- and a type with the suffix "___XVN___XVU" will be present.
-- The name of the union member is encoded to indicate the choices, and
-- is a string given by the following grammar:
-- R1T4S7S10m
- -- In the case of enumeration values, the values used are the
- -- actual representation values in the case where an enumeration type
- -- has an enumeration representation spec (i.e. they are values that
- -- correspond to the use of the Enum_Rep attribute).
+ -- In the case of enumeration values, the values used are the actual
+ -- representation values in the case where an enumeration type has an
+ -- enumeration representation spec (i.e. they are values that correspond
+ -- to the use of the Enum_Rep attribute).
- -- The type of the inner record is given by the name of the union
- -- type (as above) concatenated with the above string. Since that
- -- type may itself be variable-sized, it may also be encoded as above
- -- with a new type with a further suffix of "___XVU".
+ -- The type of the inner record is given by the name of the union type (as
+ -- above) concatenated with the above string. Since that type may itself be
+ -- variable-sized, it may also be encoded as above with a new type with a
+ -- further suffix of "___XVU".
-- As an example, consider:
-- V1 : Var;
- -- In this case, the type var is represented as a struct with three
- -- fields, the first two are "disc" and "m", representing the values
- -- of these record components.
+ -- In this case, the type var is represented as a struct with three fields,
+ -- the first two are "disc" and "m", representing the values of these
+ -- record components.
- -- The third field is a union of two types, with field names S1 and O.
- -- S1 is a struct with fields "r" and "s", and O is a struct with
- -- fields "t".
+ -- The third field is a union of two types, with field names S1 and O. S1
+ -- is a struct with fields "r" and "s", and O is a struct with fields "t".
------------------------------------------------
-- Subprograms for Handling Variant Encodings --
------------------------------------------------
procedure Get_Variant_Encoding (V : Node_Id);
- -- This procedure is called by Gigi with V being the variant node.
- -- The corresponding encoding string is returned in Name_Buffer with
- -- the length of the string in Name_Len, and an ASCII.NUL character
- -- stored following the name.
+ -- This procedure is called by Gigi with V being the variant node. The
+ -- corresponding encoding string is returned in Name_Buffer with the length
+ -- of the string in Name_Len, and an ASCII.NUL character stored following
+ -- the name.
---------------------------------
-- Subtypes of Variant Records --
-- V2 : Var (True);
-- V3 : Var (False);
- -- Here V2 for example is represented with a subtype whose name is
- -- something like TvarS3b, which is a struct with three fields. The
- -- first two fields are "disc" and "m" as for the base type, and
- -- the third field is S1, which contains the fields "r" and "s".
+ -- Here V2, for example, is represented with a subtype whose name is
+ -- something like TvarS3b, which is a struct with three fields. The first
+ -- two fields are "disc" and "m" as for the base type, and the third field
+ -- is S1, which contains the fields "r" and "s".
-- The debugger should simply ignore structs with names of the form
- -- corresponding to variants, and consider the fields inside as
- -- belonging to the containing record.
+ -- corresponding to variants, and consider the fields inside as belonging
+ -- to the containing record.
-------------------------------------------
-- Character literals in Character Types --
-------------------------------------------
- -- Character types are enumeration types at least one of whose
- -- enumeration literals is a character literal. Enumeration literals
- -- are usually simply represented using their identifier names. In
- -- the case where an enumeration literal is a character literal, the
- -- name aencoded as described in the following paragraph.
+ -- Character types are enumeration types at least one of whose enumeration
+ -- literals is a character literal. Enumeration literals are usually simply
+ -- represented using their identifier names. If the enumeration literal is
+ -- a character literal, the name aencoded as described in the following
+ -- paragraph.
- -- A name QUhh, where each 'h' is a lower-case hexadecimal digit,
- -- stands for a character whose Unicode encoding is hh, and
- -- QWhhhh likewise stands for a wide character whose encoding
- -- is hhhh. The representation values are encoded as for ordinary
- -- enumeration literals (and have no necessary relationship to the
- -- values encoded in the names).
+ -- A name QUhh, where each 'h' is a lower-case hexadecimal digit, stands
+ -- for a character whose Unicode encoding is hh, and QWhhhh likewise stands
+ -- for a wide character whose encoding is hhhh. The representation values
+ -- are encoded as for ordinary enumeration literals (and have no necessary
+ -- relationship to the values encoded in the names).
-- For example, given the type declaration
-- type x is (A, 'C', B);
- -- the second enumeration literal would be named QU43 and the
- -- value assigned to it would be 1.
+ -- the second enumeration literal would be named QU43 and the value
+ -- assigned to it would be 1.
-----------------------------------------------
-- Secondary Dispatch tables of tagged types --
Suffix_Index : Int);
-- Set Name_Buffer and Name_Len to the external name of one secondary
-- dispatch table of Typ. If the interface has been inherited from some
- -- ancestor then Ancestor_Typ is such node (in this case the secondary
- -- DT is needed to handle overriden primitives); if there is no such
- -- ancestor then Ancestor_Typ is equal to Typ.
+ -- ancestor then Ancestor_Typ is such node (in this case the secondary DT
+ -- is needed to handle overriden primitives); if there is no such ancestor
+ -- then Ancestor_Typ is equal to Typ.
--
-- Internal rule followed for the generation of the external name:
--
-- External_Name (Typ) + '_' + External_Name (Ancestor_Typ)
-- + Suffix_Number + 'P'
--
- -- Note: We have to use the external names (instead of simply their
- -- names) to protect the frontend against programs that give the same
- -- name to all the interfaces and use the expanded name to reference
- -- them. The Suffix_Number is used to differentiate all the secondary
- -- dispatch tables of a given type.
+ -- Note: We have to use the external names (instead of simply their names)
+ -- to protect the frontend against programs that give the same name to all
+ -- the interfaces and use the expanded name to reference them. The
+ -- Suffix_Number is used to differentiate all the secondary dispatch
+ -- tables of a given type.
--
-- Examples:
--
----------------------------
-- If the program is compiled with optimization on (e.g. -O1 switch
- -- specified), then there may be variations in the output from the
- -- above specification. In particular, objects may disappear from
- -- the output. This includes not only constants and variables that
- -- the program declares at the source level, but also the x___L and
- -- x___U constants created to describe the lower and upper bounds of
- -- subtypes with dynamic bounds. This means for example, that array
- -- bounds may disappear if optimization is turned on. The debugger
- -- is expected to recognize that these constants are missing and
- -- deal as best as it can with the limited information available.
+ -- specified), then there may be variations in the output from the above
+ -- specification. In particular, objects may disappear from the output.
+ -- This includes not only constants and variables that the program declares
+ -- at the source level, but also the x___L and x___U constants created to
+ -- describe the lower and upper bounds of subtypes with dynamic bounds.
+ -- This means for example, that array bounds may disappear if optimization
+ -- is turned on. The debugger is expected to recognize that these constants
+ -- are missing and deal as best as it can with the limited information
+ -- available.
end Exp_Dbug;
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