| /* cilk-abi-vla.cpp -*-C++-*- |
| * |
| ************************************************************************* |
| * |
| * Copyright (C) 2013-2016, 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. |
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| * 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 |
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| * |
| * ********************************************************************* |
| * |
| * PLEASE NOTE: This file is a downstream copy of a file mainitained in |
| * a repository at cilkplus.org. Changes made to this file that are not |
| * submitted through the contribution process detailed at |
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| * time that a new version is released. Changes only submitted to the |
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| * https://bitbucket.org/intelcilkruntime/intel-cilk-runtime.git are |
| * not tracked. |
| * |
| * We welcome your contributions to this open source project. Thank you |
| * for your assistance in helping us improve Cilk Plus. |
| * |
| **************************************************************************/ |
| |
| /* |
| * Implementation of Variable Length Array (VLA) ABI. |
| * |
| * The compiler calls these functions to allocate Variable Length Arrays |
| * at runtime. The compiler must guarantee that __cilkrts_stack_free() is |
| * called to cleanup any memory allocated by __cilkrts_stack_alloc(). |
| * |
| * This generic implementation always allocates the memory from the heap. |
| * Optimally, the implementation should expand the frame of the calling |
| * function if possible, since that will be faster. See the x86 version |
| * for one possible implementation. |
| */ |
| |
| #include <assert.h> |
| #include <stdlib.h> |
| #include <stdint.h> |
| |
| #include "internal/abi.h" |
| #include "cilk-abi-vla-internal.h" |
| |
| #define c_cilk_ptr_from_heap 0xc2f2f00d |
| #define c_cilk_ptr_from_stack 0xc3f30d0f |
| |
| // Allocate space for a variable length array |
| CILK_ABI(__cilkrts_void_ptr) |
| __cilkrts_stack_alloc( |
| __cilkrts_stack_frame *sf, |
| size_t size, |
| size_t distance_from_sp_to_alloca_area, |
| uint32_t align, // align is always >= minimum stack alignment and |
| // >= ptr_size as well, and must be a power of 2. |
| uint32_t needs_tag // non-zero if the pointer being returned needs to |
| // be tagged |
| ) |
| { |
| // full_size will be a multiple of align, and contains |
| // enough extra space to allocate a marker. |
| size_t full_size = (size + align - 1) & ~(align - 1); |
| |
| // Allocate memory from the heap. The compiler is responsible |
| // for guaranteeing us a chance to free it before the function |
| // exits |
| |
| return (void *)vla_internal_heap_alloc(sf, full_size, align); |
| } |
| |
| // Free the space allocated for a variable length array. |
| CILK_ABI(void) |
| __cilkrts_stack_free( |
| __cilkrts_stack_frame *sf, |
| void *p, |
| size_t size, |
| size_t distance_from_sp_to_alloca_area, |
| uint32_t align, // same requirements as for align in allocation, |
| // and must match alignment that was passed when |
| // doing the allocation |
| uint32_t known_from_stack // non-zero if this is known to be allocated |
| // on the stack, and therefore has no tag |
| ) |
| { |
| // full_size will be a multiple of align, and contains |
| // enough extra space to allocate a marker if one was needed. |
| size_t full_size = (size + align - 1) & ~(align - 1); |
| |
| // Just free the allocated memory to the heap since we don't know |
| // how to expand/contract the calling frame |
| vla_internal_heap_free(p, full_size); |
| } |