diff options
Diffstat (limited to 'gcc/ada/exp_dbug.ads')
| -rw-r--r-- | gcc/ada/exp_dbug.ads | 180 |
1 files changed, 87 insertions, 93 deletions
diff --git a/gcc/ada/exp_dbug.ads b/gcc/ada/exp_dbug.ads index 951ccc33a30..d17f14b0814 100644 --- a/gcc/ada/exp_dbug.ads +++ b/gcc/ada/exp_dbug.ads @@ -6,7 +6,7 @@ -- -- -- S p e c -- -- -- --- Copyright (C) 1996-2002 Free Software Foundation, Inc. -- +-- Copyright (C) 1996-2003 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- -- @@ -30,7 +30,6 @@ with Types; use Types; with Uintp; use Uintp; -with Get_Targ; use Get_Targ; package Exp_Dbug is @@ -362,28 +361,46 @@ package Exp_Dbug is -- the type, the string "PT", and a suffix which is P or N, depending on -- whether this is the protected/non-locking version of the operation. + -- Operations generated for protected entries follow the same encoding. + -- Each entry results in two suprograms: a procedure that holds the + -- entry body, and a function that holds the evaluation of the barrier. + -- The names of these subprograms include the prefix 'E' or 'B' res- + -- pectively. The names also include a numeric suffix to render them + -- unique in the presence of overloaded entries. + -- Given the declaration: - -- protected type lock is - -- function get return integer; - -- procedure set (x: integer); + -- protected type Lock is + -- function Get return Integer; + -- procedure Set (X: Integer); + -- entry Update (Val : Integer); -- private - -- value : integer := 0; - -- end lock; + -- Value : Integer := 0; + -- end Lock; -- the following operations are created: -- lockPT_getN -- lockPT_getP, + -- lockPT_setN -- lockPT_setP + -- lockPT_update1sE + -- lockPT_udpate2sB + ---------------------------------------------------- -- Conversion between Entities and External Names -- ---------------------------------------------------- - No_Dollar_In_Label : constant Boolean := Get_No_Dollar_In_Label; - -- True iff the target allows dollar signs ("$") in external names + No_Dollar_In_Label : constant Boolean := True; + -- True iff the target does not allow dollar signs ("$") in external names + -- ??? We want to migrate all platforms to use the same convention. + -- As a first step, we force this constant to always be True. This + -- constant will eventually be deleted after we have verified that + -- the migration does not cause any unforseen adverse impact. + -- We chose "__" because it is supported on all platforms, which is + -- not the case of "$". procedure Get_External_Name (Entity : Entity_Id; @@ -418,55 +435,9 @@ package Exp_Dbug is -- by homonym suffix, if the entity is an overloaded subprogram -- or is defined within an overloaded subprogram. -- - the string "___" followed by Suffix - - ---------------------------- - -- Debug Name Compression -- - ---------------------------- - - -- The full qualification of names can lead to long names, and this - -- section describes the method used to compress these names. Such - -- compression is attempted if one of the following holds: - - -- The length exceeds a maximum set in hostparm, currently set - -- to 128, but can be changed as needed. - - -- The compiler switch -gnatC is set, setting the Compress_Debug_Names - -- switch in Opt to True. - - -- If either of these conditions holds, name compression is attempted - -- by replacing the qualifying section as follows. - - -- Given a name of the form - - -- a__b__c__d - - -- where a,b,c,d are arbitrary strings not containing a sequence - -- of exactly two underscores, the name is rewritten as: - - -- XC????????_d - - -- where ???????? are 8 hex digits representing a 32-bit checksum - -- value that identifies the sequence of compressed names. In - -- addition a dummy type declaration is generated as shown by - -- the following example. Supposed we have three compression - -- sequences - - -- XC1234abcd corresponding to a__b__c__ prefix - -- XCabcd1234 corresponding to a__b__ prefix - -- XCab1234cd corresponding to a__ prefix - - -- then an enumeration type declaration is generated: - - -- type XC is - -- (XC1234abcdXnn, aXnn, bXnn, cXnn, - -- XCabcd1234Xnn, aXnn, bXnn, - -- XCab1234cdXnn, aXnn); - - -- showing the meaning of each compressed prefix, so the debugger - -- can interpret the exact sequence of names that correspond to the - -- compressed sequence. The Xnn suffixes in the above are simply - -- serial numbers that are guaranteed to be different to ensure - -- that all names are unique, and are otherwise ignored. + -- + -- If this procedure is called in the ASIS mode, it does nothing. See the + -- comments in the body for more details. -------------------------------------------- -- Subprograms for Handling Qualification -- @@ -497,11 +468,6 @@ package Exp_Dbug is -- are useful to remove qualification from a name qualified by the -- call to Qualify_All_Entity_Names. - procedure Generate_Auxiliary_Types; - -- The process of qualifying names may result in name compression which - -- requires dummy enumeration types to be generated. This subprogram - -- ensures that these types are appropriately included in the tree. - -------------------------------- -- Handling of Numeric Values -- -------------------------------- @@ -597,13 +563,14 @@ package Exp_Dbug is -- the case where one or both of the bounds are discriminants or -- variable. - -- Note: at the current time, we also encode static bounds if they - -- do not match the natural machine type bounds, but this may be - -- removed in the future, since it is redundant for most debugging - -- formats. However, we do not ever need XD encoding for enumeration - -- base types, since here it is always clear what the bounds are - -- from the number of enumeration literals, and of course we do - -- not need to encode the dummy XR types generated for renamings. + -- Note: at the current time, we also encode compile time known + -- bounds if they do not match the natural machine type bounds, + -- but this may be removed in the future, since it is redundant + -- for most debugging formats. However, we do not ever need XD + -- encoding for enumeration base types, since here it is always + -- clear what the bounds are from the total number of enumeration + -- literals, and of course we do not need to encode the dummy XR + -- types generated for renamings. -- typ___XD -- typ___XDL_lowerbound @@ -614,7 +581,7 @@ package Exp_Dbug is -- correspond in a natural manner to its size), then it is left -- unencoded. The above encoding forms are used when there is a -- constrained range that does not correspond to the size or that - -- has discriminant references or other non-static bounds. + -- has discriminant references or other compile time known bounds. -- The first form is used if both bounds are dynamic, in which case -- two constant objects are present whose names are typ___L and @@ -632,14 +599,15 @@ package Exp_Dbug is -- name as either a decimal integer, or as the discriminant name. -- The third form is similarly used if the lower bound is dynamic, - -- but the upper bound is static or a discriminant reference, in - -- which case the lower bound is stored in a constant object of - -- name typ___L, and the upper bound is encoded directly into the - -- name as either a decimal integer, or as the discriminant name. + -- but the upper bound is compile time known or a discriminant + -- reference, in which case the lower bound is stored in a constant + -- object of name typ___L, and the upper bound is encoded directly + -- into the name as either a decimal integer, or as the discriminant + -- name. -- The fourth form is used if both bounds are discriminant references - -- or static values, with the encoding first for the lower bound, - -- then for the upper bound, as previously described. + -- or compile time known values, with the encoding first for the lower + -- bound, then for the upper bound, as previously described. ------------------- -- Modular Types -- @@ -668,9 +636,9 @@ package Exp_Dbug is -- Here lowerbound and upperbound are decimal integers, with the -- usual (postfix "m") encoding for negative numbers. Biased - -- types are only possible where the bounds are static, and the - -- values are represented as unsigned offsets from the lower - -- bound given. For example: + -- types are only possible where the bounds are compile time + -- known, and the values are represented as unsigned offsets + -- from the lower bound given. For example: -- type Q is range 10 .. 15; -- for Q'size use 3; @@ -692,9 +660,10 @@ package Exp_Dbug is -- type___XVU -- The former name is used for a record and the latter for the union - -- that is made for a variant record (see below) if that union has - -- variable size. These encodings suffix any other encodings that - -- might be suffixed to the type name. + -- that is made for a variant record (see below) if that record or + -- union has a field of variable size or if the record or union itself + -- has a variable size. These encodings suffix any other encodings that + -- that might be suffixed to the type name. -- The idea here is to provide all the needed information to interpret -- objects of the original type in the form of a "fixed up" type, which @@ -1193,16 +1162,26 @@ package Exp_Dbug is -- Thin Pointers - -- Thin pointers are represented as a pointer to the ARRAY field of - -- a structure with two fields. The name of the structure type is - -- that of the unconstrained array followed by "___XUT". - - -- The field ARRAY contains the array value. This array field is - -- typically a variable-length array, and consequently the entire - -- record structure will be encoded as previously described, - -- resulting in a type with suffix "___XUT___XVE". - - -- The field BOUNDS is a struct containing the bounds as above. + -- 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 -- @@ -1360,4 +1339,19 @@ package Exp_Dbug is -- the second enumeration literal would be named QU43 and the -- value assigned to it would be 1. + ---------------------------- + -- Effect of Optimization -- + ---------------------------- + + -- 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. + end Exp_Dbug; |