------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ R E S -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2015, 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- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING3. If not, go to -- -- http://www.gnu.org/licenses for a complete copy of the license. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- Resolution processing for all subexpression nodes. Note that the separate -- package Sem_Aggr contains the actual resolution routines for aggregates, -- which are separated off since aggregate processing is complex. with Types; use Types; package Sem_Res is -- As described in Sem_Ch4, the type resolution proceeds in two phases. -- The first phase is a bottom up pass that is achieved during the -- recursive traversal performed by the Analyze procedures. This phase -- determines unambiguous types, and collects sets of possible types -- where the interpretation is potentially ambiguous. -- On completing this bottom up pass, which corresponds to a call to -- Analyze on a complete context, the Resolve routine is called which -- performs a top down resolution with recursive calls to itself to -- resolve operands. -- Since in practice a lot of semantic analysis has to be postponed until -- types are known (e.g. static folding, setting of suppress flags), the -- Resolve routines also complete the semantic analysis, and call the -- expander for possible expansion of the completely type resolved node. procedure Resolve (N : Node_Id; Typ : Entity_Id); procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id); -- Top level type-checking procedure, called in a complete context. The -- construct N, which is a subexpression, has already been analyzed, and -- is required to be of type Typ given the analysis of the context (which -- uses the information gathered on the bottom up phase in Analyze). The -- resolve routines do various other processing, e.g. static evaluation. -- If a Suppress argument is present, then the resolution is done with the -- specified check suppressed (can be All_Checks to suppress all checks). procedure Resolve (N : Node_Id); -- A version of Resolve where the type to be used for resolution is -- taken from the Etype (N). This is commonly used in cases where the -- context does not add anything and the first pass of analysis found -- the correct expected type. procedure Resolve_Discrete_Subtype_Indication (N : Node_Id; Typ : Entity_Id); -- Resolve subtype indications in choices (case statements and -- aggregates) and in index constraints. Note that the resulting Etype -- of the subtype indication node is set to the Etype of the contained -- range (i.e. an Itype is not constructed for the actual subtype). procedure Resolve_Entry (Entry_Name : Node_Id); -- Find name of entry being called, and resolve prefix of name with its -- own type. For now we assume that the prefix cannot be overloaded and -- the name of the entry plays no role in the resolution. procedure Analyze_And_Resolve (N : Node_Id); procedure Analyze_And_Resolve (N : Node_Id; Typ : Entity_Id); procedure Analyze_And_Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id); procedure Analyze_And_Resolve (N : Node_Id; Suppress : Check_Id); -- These routines combine the effect of Analyze and Resolve. If a Suppress -- argument is present, then the analysis is done with the specified check -- suppressed (can be All_Checks to suppress all checks). These checks are -- suppressed for both the analysis and resolution. If the type argument -- is not present, then the Etype of the expression after the Analyze -- call is used for the Resolve. procedure Ambiguous_Character (C : Node_Id); -- Give list of candidate interpretations when a character literal cannot -- be resolved, for example in a (useless) comparison such as 'A' = 'B'. -- In Ada 95 the literals in question can be of type Character or Wide_ -- Character. In Ada 2005 Wide_Wide_Character is also a candidate. The -- node may also be overloaded with user-defined character types. procedure Check_Parameterless_Call (N : Node_Id); -- Several forms of names can denote calls to entities without para- -- meters. The context determines whether the name denotes the entity -- or a call to it. When it is a call, the node must be rebuilt -- accordingly and reanalyzed to obtain possible interpretations. -- -- The name may be that of an overloadable construct, or it can be an -- explicit dereference of a prefix that denotes an access to subprogram. -- In that case, we want to convert the name into a call only if the -- context requires the return type of the subprogram. Finally, a -- parameterless protected subprogram appears as a selected component. -- -- The parameter T is the Typ for the corresponding resolve call. procedure Preanalyze_And_Resolve (N : Node_Id; T : Entity_Id); -- Performs a pre-analysis of expression node N. During pre-analysis, -- N is analyzed and then resolved against type T, but no expansion -- is carried out for N or its children. For more info on pre-analysis -- read the spec of Sem. procedure Preanalyze_And_Resolve (N : Node_Id); -- Same, but use type of node because context does not impose a single type function Valid_Conversion (N : Node_Id; Target : Entity_Id; Operand : Node_Id; Report_Errs : Boolean := True) return Boolean; -- Verify legality rules given in 4.6 (8-23). Target is the target type -- of the conversion, which may be an implicit conversion of an actual -- parameter to an anonymous access type (in which case N denotes the -- actual parameter and N = Operand). Returns a Boolean result indicating -- whether the conversion is legal. Reports errors in the case of illegal -- conversions, unless Report_Errs is False. private procedure Resolve_Implicit_Type (N : Node_Id) renames Resolve; pragma Inline (Resolve_Implicit_Type); -- We use this renaming to make the application of Inline very explicit -- to this version, since other versions of Resolve are not inlined. end Sem_Res;