ispc/decl.h

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*/

/** @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_UNSIGNED   (1<<4)
#define TYPEQUAL_INLINE     (1<<5)

/** @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);

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

    void Print() 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() 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;

    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