/*
  Copyright (c) 2010-2011, Intel Corporation
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

    * Neither the name of Intel Corporation nor the names of its
      contributors may be used to endorse or promote products derived from
      this software without specific prior written permission.


   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
*/

/** @file decl.h
    @brief Declarations related to type declarations; the parser basically
    creates instances of these classes, which are then turned into actual
    Types.

    Three classes work together to represent declarations.  As an example,
    consider a declaration like:

    static uniform int foo, bar[10];

    An instance of the Declaration class represents this entire declaration
    of two variables, 'foo' and 'bar'.  It holds a single instance of the
    DeclSpecs class represents the common specifiers for all of the
    variables--here, that the declaration has the 'static' and 'uniform'
    qualifiers, and that it's basic type is 'int'.  Then for each variable
    declaration, the Declaraiton class holds an instance of a Declarator,
    which in turn records the per-variable information like the symbol
    name, array size (if any), initializer expression, etc.
*/

#ifndef ISPC_DECL_H
#define ISPC_DECL_H

#include "ispc.h"

struct VariableDeclaration;

class Declaration;
class Declarator;

enum StorageClass {
    SC_NONE,
    SC_EXTERN,
    SC_EXPORT,
    SC_STATIC,
    SC_TYPEDEF,
    SC_EXTERN_C
};


/* Multiple qualifiers can be provided with types in declarations;
   therefore, they are set up so that they can be ANDed together into an
   int. */
#define TYPEQUAL_NONE           0
#define TYPEQUAL_CONST      (1<<0)
#define TYPEQUAL_UNIFORM    (1<<1)
#define TYPEQUAL_VARYING    (1<<2)
#define TYPEQUAL_TASK       (1<<3)
#define TYPEQUAL_SIGNED     (1<<4)
#define TYPEQUAL_UNSIGNED   (1<<5)
#define TYPEQUAL_INLINE     (1<<6)

/** @brief Representation of the declaration specifiers in a declaration.

    In other words, this represents all of the stuff that applies to all of
    the (possibly multiple) variables in a declaration.
 */
class DeclSpecs {
public:
    DeclSpecs(const Type *t = NULL, StorageClass sc = SC_NONE, int tq = TYPEQUAL_NONE);

    void Print() const;

    StorageClass storageClass;

    /** Zero or more of the TYPEQUAL_* values, ANDed together. */
    int typeQualifiers;

    /** The basic type provided in the declaration; this should be an
        AtomicType, EnumType, StructType, or VectorType; other types (like
        ArrayTypes) will end up being created if a particular declaration
        has an array size, etc.
    */
    const Type *baseType;

    const Type *GetBaseType(SourcePos pos) const;

    /** If this is a declaration with a vector type, this gives the vector
        width.  For non-vector types, this is zero.
     */
    int vectorSize;

    /** If this is a declaration with an "soa<n>" qualifier, this gives the
        SOA width specified.  Otherwise this is zero.
     */
    int soaWidth;
};


enum DeclaratorKind {
    DK_BASE,
    DK_POINTER,
    DK_REFERENCE,
    DK_ARRAY,
    DK_FUNCTION
};

/** @brief Representation of the declaration of a single variable.  

    In conjunction with an instance of the DeclSpecs, this gives us
    everything we need for a full variable declaration.
 */
class Declarator {
public:
    Declarator(DeclaratorKind dk, SourcePos p);

    /** Once a DeclSpecs instance is available, this method completes the
        initialization of the Symbol, setting its Type accordingly.
     */
    void InitFromDeclSpecs(DeclSpecs *ds);

    /** Get the actual type of the combination of Declarator and the given
        DeclSpecs.  If an explicit base type is provided, the declarator is
        applied to that type; otherwise the base type from the DeclSpecs is
        used. */
    const Type *GetType(DeclSpecs *ds) const;
    const Type *GetType(const Type *base, DeclSpecs *ds) const;

    /** Returns the symbol corresponding to the function declared by this
        declarator and symbols for its arguments in *args. */
    Symbol *GetFunctionInfo(DeclSpecs *ds, std::vector<Symbol *> *args);

    Symbol *GetSymbolForFunctionParameter(int paramNum) const;

    /** Returns the symbol associated with the declarator. */
    Symbol *GetSymbol() const;

    void Print(int indent) const;

    /** Position of the declarator in the source program. */
    const SourcePos pos;

    /** The kind of this declarator; complex declarations are assembled as
        a hierarchy of Declarators.  (For example, a pointer to an int
        would have a root declarator with kind DK_POINTER and with the
        Declarator::child member pointing to a DK_BASE declarator for the
        int). */
    const DeclaratorKind kind;

    /** Child pointer if needed; this can only be non-NULL if the
        declarator's kind isn't DK_BASE. */
    Declarator *child;

    /** Type qualifiers provided with the declarator. */
    int typeQualifiers;

    /** For array declarators, this gives the declared size of the array.
        Unsized arrays have arraySize == 0. */ 
    int arraySize;

    /** Symbol associated with the declarator. */
    Symbol *sym;

    /** Initialization expression for the variable.  May be NULL. */
    Expr *initExpr;

    /** For function declarations, this holds the Declaration *s for the
        funciton's parameters. */
    std::vector<Declaration *> functionParams;
};


/** @brief Representation of a full declaration of one or more variables,
    including the shared DeclSpecs as well as the per-variable Declarators.
 */
class Declaration {
public:
    Declaration(DeclSpecs *ds, std::vector<Declarator *> *dlist = NULL);
    Declaration(DeclSpecs *ds, Declarator *d);

    void Print(int indent) const;

    /** This method walks through all of the Declarators in a declaration
        and returns a fully-initialized Symbol and (possibly) and
        initialization expression for each one.  (This allows the rest of
        the system to not have to worry about the mess of the general
        Declarator representation.) */
    std::vector<VariableDeclaration> GetVariableDeclarations() const;

    /** For any function declarations in the Declaration, add the
        declaration to the module. */
    void DeclareFunctions();

    DeclSpecs *declSpecs;
    std::vector<Declarator *> declarators;
};


/** The parser creates instances of StructDeclaration for the members of
    structs as it's parsing their declarations. */
struct StructDeclaration {
    StructDeclaration(const Type *t, std::vector<Declarator *> *d)
        : type(t), declarators(d) { }

    const Type *type;
    std::vector<Declarator *> *declarators;
};


/** Given a set of StructDeclaration instances, this returns the types of
    the elements of the corresponding struct and their names. */
extern void GetStructTypesNamesPositions(const std::vector<StructDeclaration *> &sd,
                                         std::vector<const Type *> *elementTypes,
                                         std::vector<std::string> *elementNames,
                                         std::vector<SourcePos> *elementPositions);

#endif // ISPC_DECL_H
