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"

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_REFERENCE  (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 typeQualifier;

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

    /** 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;
};


/** @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(Symbol *s, SourcePos p);

    /** As the parser peels off array dimension declarations after the
        symbol name, it calls this method to provide them to the
        Declarator.
     */
    void AddArrayDimension(int size);

    /** 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 */
    const Type *GetType(DeclSpecs *ds) const;

    void Print() const;

    const SourcePos pos;
    Symbol *sym;
    /** If this declarator includes an array specification, the sizes of
        the array dimensions are represented here.
     */
    std::vector<int> arraySize;
    /** Initialization expression for the variable.  May be NULL. */
    Expr *initExpr;
    bool isFunction;
    std::vector<Declaration *> *functionArgs;
};


/** @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) {
        declSpecs = ds;
        if (dlist != NULL)
            declarators = *dlist;
        for (unsigned int i = 0; i < declarators.size(); ++i)
            if (declarators[i] != NULL)
                declarators[i]->InitFromDeclSpecs(declSpecs);
    }
    Declaration(DeclSpecs *ds, Declarator *d) {
        declSpecs = ds;
        if (d) {
            d->InitFromDeclSpecs(ds);
            declarators.push_back(d);
        }
    }

    /** Adds the symbols for the variables in the declaration to the symbol
        table. */
    void AddSymbols(SymbolTable *st) const;
    void Print() 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 GetStructTypesAndNames(const std::vector<StructDeclaration *> &sd,
                                   std::vector<const Type *> *elementTypes,
                                   std::vector<std::string> *elementNames);

#endif // ISPC_DECL_H