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-- --
-- --
-- S E M --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2021, 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 --
-- 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
-- Analyze 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 flag (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.
-- Preanalysis --
-- For certain kind of expressions, such as aggregates, we need to defer
-- expansion of the aggregate and its inner expressions until 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 this mechanism does not work is that the expanded code for the
-- children is typically inserted above the parent and thus when the parent
-- gets expanded no re-evaluation takes place. For instance in the case of
-- aggregates if "new Thing (Function_Call)" is expanded before 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 flag that signals whether we want a
-- full analysis (i.e. expansion is enabled) or a preanalysis which performs
-- Analysis and Resolution but no expansion.
-- After the complete preanalysis 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
-- preanalysis 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 Opt; use Opt;
with Table;
with Types; use Types;
package Sem is
-- Semantic Analysis Flags --
Full_Analysis : Boolean := True;
-- Switch to indicate if we are doing a full analysis or a preanalysis.
-- 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
-- Preanalysis 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_Assertion_Expr : Nat := 0;
-- This is set non-zero if we are within the expression of an assertion
-- pragma or aspect. It is incremented at the start of expanding such an
-- expression, and decremented on completion of expanding that
-- expression. This needs to be a counter, rather than a Boolean, because
-- assertions can contain declare_expressions, which can contain
-- assertions. As with In_Spec_Expression, it must be recursively saved and
-- restored for a Semantics call.
In_Declare_Expr : Nat := 0;
-- This is set non-zero if we are within a declare_expression. It is
-- incremented at the start of expanding such an expression, and
-- decremented on completion of expanding that expression. This needs to be
-- a counter, rather than a Boolean, because declare_expressions can
-- nest. As with In_Spec_Expression, it must be recursively saved and
-- restored for a Semantics call.
In_Compile_Time_Warning_Or_Error : Boolean := False;
-- Switch to indicate that we are validating a pragma Compile_Time_Warning
-- or Compile_Time_Error after the back end has been called (to check these
-- pragmas for size and alignment appropriateness).
In_Default_Expr : Boolean := False;
-- Switch to indicate that we are analyzing a default component expression.
-- As with In_Spec_Expression, it must be recursively saved and restored
-- for a Semantics call.
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.
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.
Inside_Preanalysis_Without_Freezing : Nat := 0;
-- Flag indicating whether we are preanalyzing an expression performing no
-- freezing. Non-zero means we are inside (it is actually a level counter
-- to deal with nested calls).
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
-- name) are recorded in the Sem.Scope_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_Record;
-- This variable contains the current scope based settings of the suppress
-- switches. It is initialized from Suppress_Options in Gnat1drv, and then
-- modified by pragma Suppress. On entry to each scope, the current setting
-- is saved on 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 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_Action_Kind is (Before, After, Cleanup);
type Scope_Actions is array (Scope_Action_Kind) of List_Id;
-- Transient blocks have three associated actions list, to be inserted
-- before and after the block's statements, and as cleanup actions.
Configuration_Component_Alignment : Component_Alignment_Kind :=
-- Used for handling the pragma Component_Alignment in the context of a
-- configuration file.
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_Record;
-- 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. The
-- Check_Policy pragmas are chained with Check_Policy_List pointing to
-- the most recent entry. This list is searched starting here, so that
-- the search finds the most recent appicable entry. When we restore
-- Check_Policy_List on exit from the scope, the effect is to remove
-- all entries set in the scope being exited.
Save_Default_Storage_Pool : Node_Id;
-- Save contents of Default_Storage_Pool on entry to restore on exit
Save_SPARK_Mode : SPARK_Mode_Type;
-- Setting of SPARK_Mode on entry to restore on exit
Save_SPARK_Mode_Pragma : Node_Id;
-- Setting of SPARK_Mode_Pragma on entry to restore on exit
Save_No_Tagged_Streams : Node_Id;
-- Setting of No_Tagged_Streams to restore on exit
Save_Default_SSO : Character;
-- Setting of Default_SSO on entry to restore on exit
Save_Uneval_Old : Character;
-- Setting of Uneval_Old 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 that will be wrapped
-- by the transient block.
Actions_To_Be_Wrapped : Scope_Actions;
-- Actions that have to be inserted at the start, at the end, or as
-- cleanup actions 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).
Locked_Shared_Objects : Elist_Id;
-- List of shared passive protected objects that have been locked in
-- this transient scope (always No_Elist for non-transient scopes).
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 Unlock;
-- Unlock internal tables
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);
-- 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.
procedure Insert_List_Before_And_Analyze
(N : Node_Id; L : List_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.
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).
procedure Insert_Before_First_Source_Declaration
(Stmt : Node_Id;
Decls : List_Id);
-- Insert node Stmt before the first source declaration of the related
-- subprogram's body. If no such declaration exists, Stmt becomes the last
-- declaration.
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);
-- 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);
-- 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 Preanalysis_Active return Boolean;
pragma Inline (Preanalysis_Active);
-- Determine whether preanalysis is active at the point of invocation
procedure Preanalyze (N : Node_Id);
-- Performs a preanalysis of node N. During preanalysis no expansion is
-- carried out for N or its children. See above for more info on
-- preanalysis.
with procedure Action (Item : Node_Id);
procedure Walk_Library_Items;
-- Primarily for use by CodePeer and GNATprove. Must be called after
-- semantic analysis (and expansion in the case of CodePeer) 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 Routines --
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;