compiler-rt/BlocksRuntime/Block_private.h

/*
 * Block_private.h
 * Blaine Garst
 * 2/13/2008
 *
 * SPI for Blocks

Copyright 2008-2009 Apple, Inc. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

#ifndef _BLOCK_PRIVATE_H_
#define _BLOCK_PRIVATE_H_

#if !defined(BLOCK_EXPORT)
#   if defined(__cplusplus)
#       define BLOCK_EXPORT extern "C" 
#   else
#       define BLOCK_EXPORT extern
#   endif
#endif

#include <AvailabilityMacros.h>
#include <TargetConditionals.h>

#include <stdbool.h>

#if __cplusplus
extern "C" {
#endif



enum {
    BLOCK_REFCOUNT_MASK =     (0xffff),
    BLOCK_NEEDS_FREE =        (1 << 24),
    BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
    BLOCK_HAS_CTOR =          (1 << 26), // helpers have C++ code
    BLOCK_IS_GC =             (1 << 27),
    BLOCK_IS_GLOBAL =         (1 << 28),
    BLOCK_HAS_DESCRIPTOR =    (1 << 29),
};

// revised new layout
struct Block_descriptor {
    unsigned long int reserved;
    unsigned long int size;
    void (*copy)(void *dst, void *src);
    void (*dispose)(void *);
};

struct Block_layout {
    void *isa;
    int flags;
    int reserved; 
    void (*invoke)(void *, ...);
    struct Block_descriptor *descriptor;
    // imported variables
};



struct Block_byref {
    void *isa;
    struct Block_byref *forwarding;
    int flags;//refcount;
    int size;
    void (*byref_keep)(struct Block_byref *dst, struct Block_byref *src);
    void (*byref_destroy)(struct Block_byref *);
    // long shared[0];
};

struct Block_byref_header {
    void *isa;
    struct Block_byref *forwarding;
    int flags;
    int size;
};


// Runtime support functions used by compiler when generating copy/dispose helpers

enum {
    // see function implementation for a more complete description of these fields and combinations
    BLOCK_FIELD_IS_OBJECT   =  3,  // id, NSObject, __attribute__((NSObject)), block, ...
    BLOCK_FIELD_IS_BLOCK    =  7,  // a block variable
    BLOCK_FIELD_IS_BYREF    =  8,  // the on stack structure holding the __block variable
    BLOCK_FIELD_IS_WEAK     = 16,  // declared __weak, only used in byref copy helpers
    BLOCK_BYREF_CALLER      = 128, // called from __block (byref) copy/dispose support routines.
};

// Runtime entry point called by compiler when assigning objects inside copy helper routines
BLOCK_EXPORT void _Block_object_assign(void *destAddr, const void *object, const int flags);
    // BLOCK_FIELD_IS_BYREF is only used from within block copy helpers


// runtime entry point called by the compiler when disposing of objects inside dispose helper routine
BLOCK_EXPORT void _Block_object_dispose(const void *object, const int flags);



// Other support functions

// runtime entry to get total size of a closure
BLOCK_EXPORT unsigned long int Block_size(void *block_basic);



// the raw data space for runtime classes for blocks
// class+meta used for stack, malloc, and collectable based blocks
BLOCK_EXPORT void * _NSConcreteStackBlock[32];
BLOCK_EXPORT void * _NSConcreteMallocBlock[32];
BLOCK_EXPORT void * _NSConcreteAutoBlock[32];
BLOCK_EXPORT void * _NSConcreteFinalizingBlock[32];
BLOCK_EXPORT void * _NSConcreteGlobalBlock[32];
BLOCK_EXPORT void * _NSConcreteWeakBlockVariable[32];


// the intercept routines that must be used under GC
BLOCK_EXPORT void _Block_use_GC( void *(*alloc)(const unsigned long, const bool isOne, const bool isObject),
                                  void (*setHasRefcount)(const void *, const bool),
                                  void (*gc_assign_strong)(void *, void **),
                                  void (*gc_assign_weak)(const void *, void *),
                                  void (*gc_memmove)(void *, void *, unsigned long));

// earlier version, now simply transitional
BLOCK_EXPORT void _Block_use_GC5( void *(*alloc)(const unsigned long, const bool isOne, const bool isObject),
                                  void (*setHasRefcount)(const void *, const bool),
                                  void (*gc_assign_strong)(void *, void **),
                                  void (*gc_assign_weak)(const void *, void *));

BLOCK_EXPORT void _Block_use_RR( void (*retain)(const void *),
                                 void (*release)(const void *));

// make a collectable GC heap based Block.  Not useful under non-GC.
BLOCK_EXPORT void *_Block_copy_collectable(const void *aBlock);

// thread-unsafe diagnostic
BLOCK_EXPORT const char *_Block_dump(const void *block);


// Obsolete

// first layout
struct Block_basic {
    void *isa;
    int Block_flags;  // int32_t
    int Block_size; // XXX should be packed into Block_flags
    void (*Block_invoke)(void *);
    void (*Block_copy)(void *dst, void *src);  // iff BLOCK_HAS_COPY_DISPOSE
    void (*Block_dispose)(void *);             // iff BLOCK_HAS_COPY_DISPOSE
    //long params[0];  // where const imports, __block storage references, etc. get laid down
};


#if __cplusplus
}
#endif


#endif