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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M -- -- -- -- S p e c -- -- -- -- 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- -- -- 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. -- -- -- ------------------------------------------------------------------------------ -------------------------------------- -- Semantic Analysis: General Model -- -------------------------------------- -- Semantic processing involves 3 phases which are highly intertwined -- (i.e. mutually recursive): -- Analysis implements the bulk of semantic analysis such as -- name analysis and type resolution for declarations, -- instructions and expressions. The main routine -- driving this process is procedure Analyze given below. -- This analysis phase is really a bottom up pass that is -- achieved during the recursive traversal performed by the -- Analyze_... procedures implemented in the sem_* packages. -- For expressions this phase determines unambiguous types -- and collects sets of possible types where the -- interpretation is potentially ambiguous. -- Resolution is carried out only for expressions to finish type -- resolution that was initiated but not necessarily -- completed during analysis (because of overloading -- ambiguities). Specifically, after completing the bottom -- up pass carried out during analysis for expressions, the -- Resolve routine (see the spec of sem_res for more info) -- is called to perform a top down resolution with -- recursive calls to itself to resolve operands. -- Expansion if we are not generating code this phase is a no-op. -- otherwise this phase expands, i.e. transforms, original -- declaration, expressions or instructions into simpler -- structures that can be handled by the back-end. This -- phase is also in charge of generating code which is -- implicit in the original source (for instance for -- default initializations, controlled types, etc.) -- There are two separate instances where expansion is -- invoked. For declarations and instructions, expansion is -- invoked just after analysis since no resolution needs -- to be performed. For expressions, expansion is done just -- after resolution. In both cases expansion is done from the -- bottom up just before the end of Analyze for instructions -- and declarations or the call to Resolve for expressions. -- The main routine driving expansion is Expand. -- See the spec of Expander for more details. -- To summarize, in normal code generation mode we recursively traverse the -- abstract syntax tree top-down performing semantic analysis bottom -- up. For instructions and declarations, before the call to the Analyze -- routine completes we perform expansion since at that point we have all -- semantic information needed. For expression nodes, after the call to -- Analysis terminates we invoke the Resolve routine to transmit top-down -- the type that was gathered by Analyze which will resolve possible -- ambiguities in the expression. Just before the call to Resolve -- terminates, the expression can be expanded since all the semantic -- information is available at that point. -- If we are not generating code then the expansion phase is a no-op -- When generating code there are a number of exceptions to the basic -- Analysis-Resolution-Expansion model for expressions. The most prominent -- examples are the handling of default expressions and aggregates. ----------------------------------------------------------------------- -- Handling of Default and Per-Object Expressions (Spec-Expressions) -- ----------------------------------------------------------------------- -- The default expressions in component declarations and in procedure -- specifications (but not the ones in object declarations) are quite tricky -- to handle. The problem is that some processing is required at the point -- where the expression appears: -- visibility analysis (including user defined operators) -- freezing of static expressions -- but other processing must be deferred until the enclosing entity (record or -- procedure specification) is frozen: -- freezing of any other types in the expression expansion -- generation of code -- A similar situation occurs with the argument of priority and interrupt -- priority pragmas that appear in task and protected definition specs and -- other cases of per-object expressions (see RM 3.8(18)). -- Another similar case is the conditions in precondition and postcondition -- pragmas that appear with subprogram specifications rather than in the body. -- Collectively we call these Spec_Expressions. The routine that performs the -- special analysis is called Analyze_Spec_Expression. -- Expansion has to be deferred since you can't generate code for expressions -- that reference types that have not been frozen yet. As an example, consider -- the following: -- type x is delta 0.5 range -10.0 .. +10.0; -- ... -- type q is record -- xx : x := y * z; -- end record; -- for x'small use 0.25 -- The expander is in charge of dealing with fixed-point, and of course the -- small declaration, which is not too late, since the declaration of type q -- does *not* freeze type x, definitely affects the expanded code. -- Another reason that we cannot expand early is that expansion can generate -- range checks. These range checks need to be inserted not at the point of -- definition but at the point of use. The whole point here is that the value -- of the expression cannot be obtained at the point of declaration, only at -- the point of use. -- Generally our model is to combine analysis resolution and expansion, but -- this is the one case where this model falls down. Here is how we patch -- it up without causing too much distortion to our basic model. -- A switch (In_Spec_Expression) is set to show that we are in the initial -- occurrence of a default expression. The analyzer is then called on this -- expression with the switch set true. Analysis and resolution proceed almost -- as usual, except that Freeze_Expression will not freeze non-static -- expressions if this switch is set, and the call to Expand at the end of -- resolution is skipped. This also skips the code that normally sets the -- Analyzed flag to True. The result is that when we are done the tree is -- still marked as unanalyzed, but all types for static expressions are frozen -- as required, and all entities of variables have been recorded. We then turn -- off the switch, and later on reanalyze the expression with the switch off. -- The effect is that this second analysis freezes the rest of the types as -- required, and generates code but visibility analysis is not repeated since -- all the entities are marked. -- The second analysis (the one that generates code) is in the context -- where the code is required. For a record field default, this is in the -- initialization procedure for the record and for a subprogram default -- parameter, it is at the point the subprogram is frozen. For a priority or -- storage size pragma it is in the context of the Init_Proc for the task or -- protected object. For a pre/postcondition pragma it is in the body when -- code for the pragma is generated. ------------------ -- Pre-Analysis -- ------------------ -- For certain kind of expressions, such as aggregates, we need to defer -- expansion of the aggregate and its inner expressions after the whole -- set of expressions appearing inside the aggregate have been analyzed. -- Consider, for instance the following example: -- -- (1 .. 100 => new Thing (Function_Call)) -- -- The normal Analysis-Resolution-Expansion mechanism where expansion of the -- children is performed before expansion of the parent does not work if the -- code generated for the children by the expander needs to be evaluated -- repeatedly (for instance in the above aggregate "new Thing (Function_Call)" -- needs to be called 100 times.) -- The reason why this mechanism does not work is that, the expanded code for -- the children is typically inserted above the parent and thus when the -- father gets expanded no re-evaluation takes place. For instance in the case -- of aggregates if "new Thing (Function_Call)" is expanded before of the -- aggregate the expanded code will be placed outside of the aggregate and -- when expanding the aggregate the loop from 1 to 100 will not surround the -- expanded code for "new Thing (Function_Call)". -- To remedy this situation we introduce a new flag which signals whether we -- want a full analysis (i.e. expansion is enabled) or a pre-analysis which -- performs Analysis and Resolution but no expansion. -- After the complete pre-analysis of an expression has been carried out we -- can transform the expression and then carry out the full three stage -- (Analyze-Resolve-Expand) cycle on the transformed expression top-down so -- that the expansion of inner expressions happens inside the newly generated -- node for the parent expression. -- Note that the difference between processing of default expressions and -- pre-analysis of other expressions is that we do carry out freezing in -- the latter but not in the former (except for static scalar expressions). -- The routine that performs preanalysis and corresponding resolution is -- called Preanalyze_And_Resolve and is in Sem_Res. with Alloc; with Einfo; use Einfo; with Opt; use Opt; with Table; with Types; use Types; package Sem is New_Nodes_OK : Int := 1; -- Temporary flag for use in checking out HLO. Set non-zero if it is -- OK to generate new nodes. ----------------------------- -- Semantic Analysis Flags -- ----------------------------- Full_Analysis : Boolean := True; -- Switch to indicate if we are doing a full analysis or a pre-analysis. -- In normal analysis mode (Analysis-Expansion for instructions or -- declarations) or (Analysis-Resolution-Expansion for expressions) this -- flag is set. Note that if we are not generating code the expansion phase -- merely sets the Analyzed flag to True in this case. If we are in -- Pre-Analysis mode (see above) this flag is set to False then the -- expansion phase is skipped. -- -- When this flag is False the flag Expander_Active is also False (the -- Expander_Active flag defined in the spec of package Expander tells you -- whether expansion is currently enabled). You should really regard this -- as a read only flag. In_Spec_Expression : Boolean := False; -- Switch to indicate that we are in a spec-expression, as described -- above. Note that this must be recursively saved on a Semantics call -- since it is possible for the analysis of an expression to result in a -- recursive call (e.g. to get the entity for System.Address as part of the -- processing of an Address attribute reference). When this switch is True -- then Full_Analysis above must be False. You should really regard this as -- a read only flag. In_Deleted_Code : Boolean := False; -- If the condition in an if-statement is statically known, the branch -- that is not taken is analyzed with expansion disabled, and the tree -- is deleted after analysis. Itypes generated in deleted code must be -- frozen from start, because the tree on which they depend will not -- be available at the freeze point. In_Inlined_Body : Boolean := False; -- Switch to indicate that we are analyzing and resolving an inlined body. -- Type checking is disabled in this context, because types are known to be -- compatible. This avoids problems with private types whose full view is -- derived from private types. Inside_A_Generic : Boolean := False; -- This flag is set if we are processing a generic specification, generic -- definition, or generic body. When this flag is True the Expander_Active -- flag is False to disable any code expansion (see package Expander). Only -- the generic processing can modify the status of this flag, any other -- client should regard it as read-only. -- Probably should be called Inside_A_Generic_Template ??? Inside_Freezing_Actions : Nat := 0; -- Flag indicating whether we are within a call to Expand_N_Freeze_Actions. -- Non-zero means we are inside (it is actually a level counter to deal -- with nested calls). Used to avoid traversing the tree each time a -- subprogram call is processed to know if we must not clear all constant -- indications from entities in the current scope. Only the expansion of -- freezing nodes can modify the status of this flag, any other client -- should regard it as read-only. Unloaded_Subunits : Boolean := False; -- This flag is set True if we have subunits that are not loaded. This -- occurs when the main unit is a subunit, and contains lower level -- subunits that are not loaded. We use this flag to suppress warnings -- about unused variables, since these warnings are unreliable in this -- case. We could perhaps do a more accurate job and retain some of the -- warnings, but it is quite a tricky job. ----------------------------------- -- Handling of Check Suppression -- ----------------------------------- -- There are two kinds of suppress checks: scope based suppress checks, -- and entity based suppress checks. -- Scope based suppress checks for the predefined checks (from initial -- command line arguments, or from Suppress pragmas not including an entity -- entity name) are recorded in the Sem.Suppress variable, and all that is -- necessary is to save the state of this variable on scope entry, and -- restore it on scope exit. This mechanism allows for fast checking of -- the scope suppress state without needing complex data structures. -- Entity based checks, from Suppress/Unsuppress pragmas giving an -- Entity_Id and scope based checks for non-predefined checks (introduced -- using pragma Check_Name), are handled as follows. If a suppress or -- unsuppress pragma is encountered for a given entity, then the flag -- Checks_May_Be_Suppressed is set in the entity and an entry is made in -- either the Local_Entity_Suppress stack (case of pragma that appears in -- other than a package spec), or in the Global_Entity_Suppress stack (case -- of pragma that appears in a package spec, which is by the rule of RM -- 11.5(7) applicable throughout the life of the entity). Similarly, a -- Suppress/Unsuppress pragma for a non-predefined check which does not -- specify an entity is also stored in one of these stacks. -- If the Checks_May_Be_Suppressed flag is set in an entity then the -- procedure is to search first the local and then the global suppress -- stacks (we search these in reverse order, top element first). The only -- other point is that we have to make sure that we have proper nested -- interaction between such specific pragmas and locally applied general -- pragmas applying to all entities. This is achieved by including in the -- Local_Entity_Suppress table dummy entries with an empty Entity field -- that are applicable to all entities. A similar search is needed for any -- non-predefined check even if no specific entity is involved. Scope_Suppress : Suppress_Array := Suppress_Options; -- This array contains the current scope based settings of the suppress -- switches. It is initialized from the options as shown, and then modified -- by pragma Suppress. On entry to each scope, the current setting is saved -- the scope stack, and then restored on exit from the scope. This record -- may be rapidly checked to determine the current status of a check if -- no specific entity is involved or if the specific entity involved is -- one for which no specific Suppress/Unsuppress pragma has been set (as -- indicated by the Checks_May_Be_Suppressed flag being set). -- This scheme is a little complex, but serves the purpose of enabling -- a very rapid check in the common case where no entity specific pragma -- applies, and gives the right result when such pragmas are used even -- in complex cases of nested Suppress and Unsuppress pragmas. -- The Local_Entity_Suppress and Global_Entity_Suppress stacks are handled -- using dynamic allocation and linked lists. We do not often use this -- approach in the compiler (preferring to use extensible tables instead). -- The reason we do it here is that scope stack entries save a pointer to -- the current local stack top, which is also saved and restored on scope -- exit. Furthermore for processing of generics we save pointers to the -- top of the stack, so that the local stack is actually a tree of stacks -- rather than a single stack, a structure that is easy to represent using -- linked lists, but impossible to represent using a single table. Note -- that because of the generic issue, we never release entries in these -- stacks, but that's no big deal, since we are unlikely to have a huge -- number of Suppress/Unsuppress entries in a single compilation. type Suppress_Stack_Entry; type Suppress_Stack_Entry_Ptr is access all Suppress_Stack_Entry; type Suppress_Stack_Entry is record Entity : Entity_Id; -- Entity to which the check applies, or Empty for a check that has -- no entity name (and thus applies to all entities). Check : Check_Id; -- Check which is set (can be All_Checks for the All_Checks case) Suppress : Boolean; -- Set True for Suppress, and False for Unsuppress Prev : Suppress_Stack_Entry_Ptr; -- Pointer to previous entry on stack Next : Suppress_Stack_Entry_Ptr; -- All allocated Suppress_Stack_Entry records are chained together in -- a linked list whose head is Suppress_Stack_Entries, and the Next -- field is used as a forward pointer (null ends the list). This is -- used to free all entries in Sem.Init (which will be important if -- we ever setup the compiler to be reused). end record; Suppress_Stack_Entries : Suppress_Stack_Entry_Ptr := null; -- Pointer to linked list of records (see comments for Next above) Local_Suppress_Stack_Top : Suppress_Stack_Entry_Ptr; -- Pointer to top element of local suppress stack. This is the entry that -- is saved and restored in the scope stack, and also saved for generic -- body expansion. Global_Suppress_Stack_Top : Suppress_Stack_Entry_Ptr; -- Pointer to top element of global suppress stack procedure Push_Local_Suppress_Stack_Entry (Entity : Entity_Id; Check : Check_Id; Suppress : Boolean); -- Push a new entry on to the top of the local suppress stack, updating -- the value in Local_Suppress_Stack_Top; procedure Push_Global_Suppress_Stack_Entry (Entity : Entity_Id; Check : Check_Id; Suppress : Boolean); -- Push a new entry on to the top of the global suppress stack, updating -- the value in Global_Suppress_Stack_Top; ----------------- -- Scope Stack -- ----------------- -- The scope stack indicates the declarative regions that are currently -- being processed (analyzed and/or expanded). The scope stack is one of -- the basic visibility structures in the compiler: entities that are -- declared in a scope that is currently on the scope stack are immediately -- visible (leaving aside issues of hiding and overloading). -- Initially, the scope stack only contains an entry for package Standard. -- When a compilation unit, subprogram unit, block or declarative region -- is being processed, the corresponding entity is pushed on the scope -- stack. It is removed after the processing step is completed. A given -- entity can be placed several times on the scope stack, for example -- when processing derived type declarations, freeze nodes, etc. The top -- of the scope stack is the innermost scope currently being processed. -- It is obtained through function Current_Scope. After a compilation unit -- has been processed, the scope stack must contain only Standard. -- The predicate In_Open_Scopes specifies whether a scope is currently -- on the scope stack. -- This model is complicated by the need to compile units on the fly, in -- the middle of the compilation of other units. This arises when compiling -- instantiations, and when compiling run-time packages obtained through -- rtsfind. Given that the scope stack is a single static and global -- structure (not originally designed for the recursive processing required -- by rtsfind for example) additional machinery is needed to indicate what -- is currently being compiled. As a result, the scope stack holds several -- contiguous sections that correspond to the compilation of a given -- compilation unit. These sections are separated by distinct occurrences -- of package Standard. The currently active section of the scope stack -- goes from the current scope to the first (innermost) occurrence of -- Standard, which is additionally marked with the flag -- Is_Active_Stack_Base. The basic visibility routine (Find_Direct_Name, in -- Sem_Ch8) uses this contiguous section of the scope stack to determine -- whether a given entity is or is not visible at a point. In_Open_Scopes -- only examines the currently active section of the scope stack. -- Similar complications arise when processing child instances. These -- must be compiled in the context of parent instances, and therefore the -- parents must be pushed on the stack before compiling the child, and -- removed afterwards. Routines Save_Scope_Stack and Restore_Scope_Stack -- are used to set/reset the visibility of entities declared in scopes -- that are currently on the scope stack, and are used when compiling -- instance bodies on the fly. -- It is clear in retrospect that all semantic processing and visibility -- structures should have been fully recursive. The rtsfind mechanism, -- and the complexities brought about by subunits and by generic child -- units and their instantiations, have led to a hybrid model that carries -- more state than one would wish. type Scope_Stack_Entry is record Entity : Entity_Id; -- Entity representing the scope Last_Subprogram_Name : String_Ptr; -- Pointer to name of last subprogram body in this scope. Used for -- testing proper alpha ordering of subprogram bodies in scope. Save_Scope_Suppress : Suppress_Array; -- Save contents of Scope_Suppress on entry Save_Local_Suppress_Stack_Top : Suppress_Stack_Entry_Ptr; -- Save contents of Local_Suppress_Stack on entry to restore on exit Save_Check_Policy_List : Node_Id; -- Save contents of Check_Policy_List on entry to restore on exit Save_Default_Storage_Pool : Node_Id; -- Save contents of Default_Storage_Pool on entry to restore on exit Is_Transient : Boolean; -- Marks transient scopes (see Exp_Ch7 body for details) Previous_Visibility : Boolean; -- Used when installing the parent(s) of the current compilation unit. -- The parent may already be visible because of an ongoing compilation, -- and the proper visibility must be restored on exit. The flag is -- typically needed when the context of a child unit requires -- compilation of a sibling. In other cases the flag is set to False. -- See Sem_Ch10 (Install_Parents, Remove_Parents). Node_To_Be_Wrapped : Node_Id; -- Only used in transient scopes. Records the node which will -- be wrapped by the transient block. Actions_To_Be_Wrapped_Before : List_Id; Actions_To_Be_Wrapped_After : List_Id; -- Actions that have to be inserted at the start or at the end of a -- transient block. Used to temporarily hold these actions until the -- block is created, at which time the actions are moved to the block. Pending_Freeze_Actions : List_Id; -- Used to collect freeze entity nodes and associated actions that are -- generated in an inner context but need to be analyzed outside, such -- as records and initialization procedures. On exit from the scope, -- this list of actions is inserted before the scope construct and -- analyzed to generate the corresponding freeze processing and -- elaboration of other associated actions. First_Use_Clause : Node_Id; -- Head of list of Use_Clauses in current scope. The list is built when -- the declarations in the scope are processed. The list is traversed -- on scope exit to undo the effect of the use clauses. Component_Alignment_Default : Component_Alignment_Kind; -- Component alignment to be applied to any record or array types that -- are declared for which a specific component alignment pragma does not -- set the alignment. Is_Active_Stack_Base : Boolean; -- Set to true only when entering the scope for Standard_Standard from -- from within procedure Semantics. Indicates the base of the current -- active set of scopes. Needed by In_Open_Scopes to handle cases where -- Standard_Standard can be pushed anew on the scope stack to start a -- new active section (see comment above). end record; package Scope_Stack is new Table.Table ( Table_Component_Type => Scope_Stack_Entry, Table_Index_Type => Int, Table_Low_Bound => 0, Table_Initial => Alloc.Scope_Stack_Initial, Table_Increment => Alloc.Scope_Stack_Increment, Table_Name => "Sem.Scope_Stack"); ----------------- -- Subprograms -- ----------------- procedure Initialize; -- Initialize internal tables procedure Lock; -- Lock internal tables before calling back end procedure Semantics (Comp_Unit : Node_Id); -- This procedure is called to perform semantic analysis on the specified -- node which is the N_Compilation_Unit node for the unit. procedure Analyze (N : Node_Id); procedure Analyze (N : Node_Id; Suppress : Check_Id); -- This is the recursive procedure that is applied to individual nodes of -- the tree, starting at the top level node (compilation unit node) and -- then moving down the tree in a top down traversal. It calls individual -- routines with names Analyze_xxx to analyze node xxx. Each of these -- routines is responsible for calling Analyze on the components of the -- subtree. -- -- Note: In the case of expression components (nodes whose Nkind is in -- N_Subexpr), the call to Analyze does not complete the semantic analysis -- of the node, since the type resolution cannot be completed until the -- complete context is analyzed. The completion of the type analysis occurs -- in the corresponding Resolve routine (see Sem_Res). -- -- Note: for integer and real literals, the analyzer sets the flag to -- indicate that the result is a static expression. If the expander -- generates a literal that does NOT correspond to a static expression, -- e.g. by folding an expression whose value is known at compile-time, -- but is not technically static, then the caller should reset the -- Is_Static_Expression flag after analyzing but before resolving. -- -- If the Suppress argument is present, then the analysis is done -- with the specified check suppressed (can be All_Checks to suppress -- all checks). procedure Analyze_List (L : List_Id); procedure Analyze_List (L : List_Id; Suppress : Check_Id); -- Analyzes each element of a list. If the Suppress argument is present, -- then the analysis is done with the specified check suppressed (can -- be All_Checks to suppress all checks). procedure Copy_Suppress_Status (C : Check_Id; From : Entity_Id; To : Entity_Id); -- If From is an entity for which check C is explicitly suppressed -- then also explicitly suppress the corresponding check in To. procedure Insert_List_After_And_Analyze (N : Node_Id; L : List_Id); procedure Insert_List_After_And_Analyze (N : Node_Id; L : List_Id; Suppress : Check_Id); -- Inserts list L after node N using Nlists.Insert_List_After, and then, -- after this insertion is complete, analyzes all the nodes in the list, -- including any additional nodes generated by this analysis. If the list -- is empty or No_List, the call has no effect. If the Suppress argument is -- present, then the analysis is done with the specified check suppressed -- (can be All_Checks to suppress all checks). procedure Insert_List_Before_And_Analyze (N : Node_Id; L : List_Id); procedure Insert_List_Before_And_Analyze (N : Node_Id; L : List_Id; Suppress : Check_Id); -- Inserts list L before node N using Nlists.Insert_List_Before, and then, -- after this insertion is complete, analyzes all the nodes in the list, -- including any additional nodes generated by this analysis. If the list -- is empty or No_List, the call has no effect. If the Suppress argument is -- present, then the analysis is done with the specified check suppressed -- (can be All_Checks to suppress all checks). procedure Insert_After_And_Analyze (N : Node_Id; M : Node_Id); procedure Insert_After_And_Analyze (N : Node_Id; M : Node_Id; Suppress : Check_Id); -- Inserts node M after node N and then after the insertion is complete, -- analyzes the inserted node and all nodes that are generated by -- this analysis. If the node is empty, the call has no effect. If the -- Suppress argument is present, then the analysis is done with the -- specified check suppressed (can be All_Checks to suppress all checks). procedure Insert_Before_And_Analyze (N : Node_Id; M : Node_Id); procedure Insert_Before_And_Analyze (N : Node_Id; M : Node_Id; Suppress : Check_Id); -- Inserts node M before node N and then after the insertion is complete, -- analyzes the inserted node and all nodes that could be generated by -- this analysis. If the node is empty, the call has no effect. If the -- Suppress argument is present, then the analysis is done with the -- specified check suppressed (can be All_Checks to suppress all checks). function External_Ref_In_Generic (E : Entity_Id) return Boolean; -- Return True if we are in the context of a generic and E is -- external (more global) to it. procedure Enter_Generic_Scope (S : Entity_Id); -- Shall be called each time a Generic subprogram or package scope is -- entered. S is the entity of the scope. -- ??? At the moment, only called for package specs because this mechanism -- is only used for avoiding freezing of external references in generics -- and this can only be an issue if the outer generic scope is a package -- spec (otherwise all external entities are already frozen) procedure Exit_Generic_Scope (S : Entity_Id); -- Shall be called each time a Generic subprogram or package scope is -- exited. S is the entity of the scope. -- ??? At the moment, only called for package specs exit. function Explicit_Suppress (E : Entity_Id; C : Check_Id) return Boolean; -- This function returns True if an explicit pragma Suppress for check C -- is present in the package defining E. function Is_Check_Suppressed (E : Entity_Id; C : Check_Id) return Boolean; -- This function is called if Checks_May_Be_Suppressed (E) is True to -- determine whether check C is suppressed either on the entity E or -- as the result of a scope suppress pragma. If Checks_May_Be_Suppressed -- is False, then the status of the check can be determined simply by -- examining Scope_Checks (C), so this routine is not called in that case. generic with procedure Action (Item : Node_Id); procedure Walk_Library_Items; -- Primarily for use by SofCheck Inspector. Must be called after semantic -- analysis (and expansion) are complete. Walks each relevant library item, -- calling Action for each, in an order such that one will not run across -- forward references. Each Item passed to Action is the declaration or -- body of a library unit, including generics and renamings. The first item -- is the N_Package_Declaration node for package Standard. Bodies are not -- included, except for the main unit itself, which always comes last. -- -- Item is never a subunit -- -- Item is never an instantiation. Instead, the instance declaration is -- passed, and (if the instantiation is the main unit), the instance body. -- Debugging: function ss (Index : Int) return Scope_Stack_Entry; pragma Export (Ada, ss); -- "ss" = "scope stack"; returns the Index'th entry in the Scope_Stack function sst return Scope_Stack_Entry; pragma Export (Ada, sst); -- "sst" = "scope stack top"; same as ss(Scope_Stack.Last) end Sem;
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