forked from 0ad/0ad
janwas
0fa54bc56a
thanks to daniel.santos for reporting and alex for creating the ticket/notifying me. fixes #992 [heh, the amount of comments are proportional to the trouble caused by this code :S ran into VC++ compile errors when __declspec came after void* return type *sigh*] This was SVN commit r10385.
88 lines
2.5 KiB
C++
88 lines
2.5 KiB
C++
#include "precompiled.h"
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#include "lib/allocators/unique_range.h"
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#include "lib/bits.h" // is_pow2, round_up
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#include "lib/sysdep/cpu.h" // cpu_AtomicAdd
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#include "lib/sysdep/rtl.h" // rtl_FreeAligned
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// (hardwired index avoids RegisterUniqueRangeDeleter overhead for
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// this commonly used allocator.)
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static const IdxDeleter idxDeleterAligned = 1;
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static void FreeNone(void* UNUSED(pointer), size_t UNUSED(size))
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{
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// (providing a deleter function for idxDeleterNone avoids
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// having to check whether deleters[idxDeleter] == 0)
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}
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static void FreeAligned(void* pointer, size_t UNUSED(size))
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{
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return rtl_FreeAligned(pointer);
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}
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static UniqueRangeDeleter deleters[allocationAlignment] = { FreeNone, FreeAligned };
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static IdxDeleter numDeleters = 2;
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// NB: callers should skip this if *idxDeleterOut != 0 (avoids the overhead
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// of an unnecessary indirect function call)
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void RegisterUniqueRangeDeleter(UniqueRangeDeleter deleter, volatile IdxDeleter* idxDeleterOut)
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{
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ENSURE(deleter);
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if(!cpu_CAS(idxDeleterOut, idxDeleterNone, -1)) // not the first call for this deleter
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{
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// wait until an index has been assigned
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while(*idxDeleterOut <= 0)
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cpu_Pause();
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return;
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}
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const IdxDeleter idxDeleter = cpu_AtomicAdd(&numDeleters, 1);
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ENSURE(idxDeleter < (IdxDeleter)ARRAY_SIZE(deleters));
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deleters[idxDeleter] = deleter;
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COMPILER_FENCE;
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*idxDeleterOut = idxDeleter;
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}
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NOTHROW_DEFINE void CallUniqueRangeDeleter(void* pointer, size_t size, IdxDeleter idxDeleter)
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{
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ASSERT(idxDeleter < numDeleters);
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// (some deleters do not tolerate null pointers)
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if(pointer)
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deleters[idxDeleter](pointer, size);
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}
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UniqueRange AllocateAligned(size_t size, size_t alignment)
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{
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ENSURE(is_pow2(alignment));
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alignment = std::max(alignment, allocationAlignment);
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const size_t alignedSize = round_up(size, alignment);
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const UniqueRange::pointer p = rtl_AllocateAligned(alignedSize, alignment);
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static volatile IdxDeleter idxDeleterAligned;
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if(idxDeleterAligned == 0) // (optional optimization)
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RegisterUniqueRangeDeleter(FreeAligned, &idxDeleterAligned);
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return RVALUE(UniqueRange(p, size, idxDeleterAligned));
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}
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UniqueRange AllocateVM(size_t size, vm::PageType pageType, int prot)
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{
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const UniqueRange::pointer p = vm::Allocate(size, pageType, prot);
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static volatile IdxDeleter idxDeleter;
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if(idxDeleter == 0) // (optional optimization)
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RegisterUniqueRangeDeleter(vm::Free, &idxDeleter);
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return RVALUE(UniqueRange(p, size, idxDeleter));
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}
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