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Diffstat (limited to 'src/vhdl/sem_expr.ads')
| -rw-r--r-- | src/vhdl/sem_expr.ads | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/src/vhdl/sem_expr.ads b/src/vhdl/sem_expr.ads new file mode 100644 index 0000000..a0422e7 --- /dev/null +++ b/src/vhdl/sem_expr.ads @@ -0,0 +1,178 @@ +-- Semantic analysis. +-- Copyright (C) 2002, 2003, 2004, 2005 Tristan Gingold +-- +-- GHDL is free software; you can redistribute it and/or modify it under +-- the terms of the GNU General Public License as published by the Free +-- Software Foundation; either version 2, or (at your option) any later +-- version. +-- +-- GHDL is distributed in the hope that it will be useful, but WITHOUT 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 +-- along with GHDL; see the file COPYING. If not, write to the Free +-- Software Foundation, 59 Temple Place - Suite 330, Boston, MA +-- 02111-1307, USA. +with Types; use Types; +with Iirs; use Iirs; + +package Sem_Expr is + -- Set semantic to EXPR. + -- Replace simple_name with the referenced node, + -- Set type to nodes, + -- Resolve overloading + + Deferred_Constant_Allowed : Boolean := False; + + -- Semantize an expression (other than a range) with a possible overloading. + -- Sem_expression_ov (and therefore sem_expression) must be called *once* + -- for each expression node with A_TYPE1 not null and at most *once* with + -- A_TYPE1 null. + -- + -- When A_TYPE1 is null, sem_expression_ov find all possible types + -- of the expression. If there is only one possible type (ie, overloading + -- is non-existant or solved), then the type of the expression is set, + -- and the node is completly semantized. Sem_expression_ov must not + -- be called for such a node. + -- If there is several possible types (ie overloaded), then the type is + -- set with a list of overload. To finishes the semantisation, + -- sem_expression_ov must be called again with A_TYPE1 set to the + -- expected type. + -- + -- If A_TYPE1 is set, sem_expression_ov must finishes the semantisation + -- of the expression, and set its type, which is not necessary a base type. + -- A_TYPE1 must be a base type. + -- + -- In case of error, it displays a message and return null. + -- In case of success, it returns the semantized expression, which can + -- be different from EXPR (eg, a character literal is transformed into an + -- enumeration literal). + function Sem_Expression_Ov (Expr: Iir; A_Type1: Iir) return Iir; + + -- If A_TYPE is not null, then EXPR must be of type A_TYPE. + -- Return null in case of error. + function Sem_Expression (Expr: Iir; A_Type: Iir) return Iir; + + -- Same as Sem_Expression, but also implicitly choose an universal type + -- if overloaded. + function Sem_Expression_Universal (Expr : Iir) return Iir; + + -- Same as Sem_Expression but specialized for a case expression. + -- (Handle specific overloading rules). + function Sem_Case_Expression (Expr : Iir) return Iir; + + -- Sem COND as a condition. + -- In VHDL08, this follows 9.2.9 Condition operator. + -- In VHDL87 and 93, type of COND must be a boolean. + -- A check is made that COND can be read. + function Sem_Condition (Cond : Iir) return Iir; + + -- Same as Sem_Expression but knowing that the type of EXPR must be a + -- composite type. Used for expressions in assignment statement when the + -- target is an aggregate. + function Sem_Composite_Expression (Expr : Iir) return Iir; + + -- Check EXPR can be read. + procedure Check_Read (Expr : Iir); + + -- Check EXPR can be updated. + procedure Check_Update (Expr : Iir); + + -- Check the type of EXPR can be implicitly converted to TARG_TYPE, ie + -- if TARG_TYPE is a constrained array subtype, number of elements matches. + -- Return FALSE in case of error. + -- If TARG_TYPE or EXPR is NULL_IIR, silently returns TRUE. + function Check_Implicit_Conversion (Targ_Type : Iir; Expr : Iir) + return Boolean; + + -- For a procedure call, A_TYPE must be null. + function Sem_Subprogram_Call (Expr: Iir; A_Type: Iir) return Iir; + + -- If EXPR is a node for an expression, then return EXPR. + -- Otherwise, emit an error message using LOC as location + -- and return NULL_IIR. + -- If EXPR is NULL_IIR, NULL_IIR is silently returned. + function Check_Is_Expression (Expr : Iir; Loc : Iir) return Iir; + + -- Semantize a procedure_call or a concurrent_procedure_call_statement. + -- A procedure call is not an expression but because most of the code + -- for procedure call is common with function call, procedure calls are + -- handled in this package. + procedure Sem_Procedure_Call (Call : Iir_Procedure_Call; Stmt : Iir); + + -- Analyze a range (ie a range attribute or a range expression). If + -- ANY_DIR is true, the range can't be a null range (slice vs subtype, + -- used in static evaluation). A_TYPE may be Null_Iir. + -- Return Null_Iir in case of error, or EXPR analyzed (and evaluated if + -- possible). + function Sem_Range_Expression (Expr: Iir; A_Type: Iir; Any_Dir : Boolean) + return Iir; + + -- Analyze a discrete range. If ANY_DIR is true, the range can't be a + -- null range (slice vs subtype -- used in static evaluation). A_TYPE may + -- be Null_Iir. Return Null_Iir in case of error. + function Sem_Discrete_Range_Expression + (Expr: Iir; A_Type: Iir; Any_Dir: Boolean) return Iir; + + -- Semantize a discrete range and convert to integer if both bounds are + -- universal integer types, according to rules of LRM 3.2.1.1 + function Sem_Discrete_Range_Integer (Expr: Iir) return Iir; + + -- Transform LIT into a physical_literal. + -- LIT can be either a not semantized physical literal or + -- a simple name that is a physical unit. In the later case, a physical + -- literal is created. + function Sem_Physical_Literal (Lit: Iir) return Iir; + + -- CHOICES_LIST is a list of choices (none, expression, range, list or + -- others). + -- If IS_SUB_RANGE is true, then SUB_TYPE may not be fully convered, + -- otherwise, SUB_TYPE must be fully covered. + -- This is used when the subtype of an aggregate must be determined. + -- SUB_TYPE is the discrete subtype. + -- Emit a message if: + -- * the SUB_TYPE is not fully covered by the choices + -- * the choices are not mutually exclusif (an element is present twice) + -- * OTHERS is not the last choice, or is present several times. + -- + -- If there is at least one named choice, LOW and HIGH are set with the + -- lowest and highest index. + -- If LOW and HIGH are set, they are locally static. + -- + -- Unidimensional strings are not handled here but by + -- sem_string_choices_range. + -- + -- TODO: + -- * be smarter if only positional choices (do not create the list). + -- * smarter messages. + procedure Sem_Choices_Range + (Choice_Chain : in out Iir; + Sub_Type : Iir; + Is_Sub_Range : Boolean; + Is_Case_Stmt : Boolean; + Loc : Location_Type; + Low : out Iir; + High : out Iir); + + -- Semantize CHOICE_LIST when the choice expression SEL is of a + -- one-dimensional character array type. + procedure Sem_String_Choices_Range (Choice_Chain : Iir; Sel : Iir); + + -- LEFT are RIGHT must be really a type (not a subtype). + function Are_Basetypes_Compatible (Left: Iir; Right: Iir) + return Boolean; + + -- Return TRUE iif types of LEFT and RIGHT are compatible. + function Are_Nodes_Compatible (Left: Iir; Right: Iir) + return Boolean; + + -- Return TRUE iff the type of EXPR is compatible with A_TYPE + function Is_Expr_Compatible (A_Type : Iir; Expr : Iir) return Boolean; + + -- LIST1, LIST2 are either a type node or an overload list of types. + -- Return THE type which is compatible with LIST1 are LIST2. + -- Return null_iir if there is no such type or if there are several types. + function Search_Compatible_Type (List1, List2 : Iir) return Iir; +end Sem_Expr; |