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/*
* Copyright (C) 2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#if ENABLE(B3_JIT)
#include "JITOperationValidation.h"
namespace JSC { namespace B3 {
class Procedure;
// Apply transformations that match and simplify entire loops.
bool reduceLoopStrength(Procedure&);
#if CPU(X86_64)
/*
* The semantics of B3 require that loads and stores are not reduced in granularity.
* If we would use system memcpy, then it is possible that we would get a byte copy loop,
* and this could cause GC tearing.
*/
ALWAYS_INLINE void fastForwardCopy32(uint32_t* dst, const uint32_t* src, size_t size)
{
uint64_t i;
int64_t counter;
uint64_t tmp, tmp2;
asm volatile(
"test %q[size], %q[size]\t\n"
"jz 900f\t\n" // exit
"xorq %q[i], %q[i]\t\n"
// if size < 8
"cmp $8, %q[size]\t\n"
"jl 100f\t\n" // backporch
// if (dst + size*4 <= src || src + size*4 <= dst)
"leaq (%q[src], %q[size], 4), %q[tmp]\t\n"
"cmp %q[tmp], %q[dst]\t\n"
"jae 500f\t\n" // simd no overlap
"leaq (%q[dst], %q[size], 4), %q[tmp]\t\n"
"cmp %q[tmp], %q[src]\t\n"
"jae 500f\t\n" // simd no overlap
"jmp 100f\t\n" // Backporch
// Backporch (assumes we can write at least one int)
"100:\t\n"
// counter = (size - i)%4
"mov %q[size], %q[counter]\t\n"
"subq %q[i], %q[counter]\t\n"
// If we are a multiple of 4, unroll the loop
// We already know we are nonzero
"and $3, %q[counter]\t\n"
"jz 200f\t\n" // unrolled loop
"negq %q[counter]\t\n"
".balign 32\t\n"
"101:\t\n"
"mov (%q[src], %q[i], 4), %k[tmp]\t\n"
"mov %k[tmp], (%q[dst], %q[i], 4)\t\n"
"incq %q[i]\t\n"
"incq %q[counter]\t\n"
"jnz 101b\t\n"
// Do we still have anything left?
"cmpq %q[size], %q[i]\t\n"
"je 900f\t\n" // exit
// Then go to the unrolled loop
"jmp 200f\t\n"
// Unrolled loop (assumes multiple of 4, can do one iteration)
"200:\t\n"
"shr $2, %q[counter]\t\n"
"negq %q[counter]\t\n"
".balign 32\t\n"
"201:\t\n"
"mov (%q[src], %q[i], 4), %k[tmp]\t\n"
"mov %k[tmp], (%q[dst], %q[i], 4)\t\n"
"mov 4(%q[src], %q[i], 4), %k[tmp2]\t\n"
"mov %k[tmp2], 4(%q[dst], %q[i], 4)\t\n"
"mov 8(%q[src], %q[i], 4), %k[tmp2]\t\n"
"mov %k[tmp2], 8(%q[dst], %q[i], 4)\t\n"
"mov 12(%q[src], %q[i], 4), %k[tmp]\t\n"
"mov %k[tmp], 12(%q[dst], %q[i], 4)\t\n"
"addq $4, %q[i]\t\n"
"cmpq %q[size], %q[i]\t\n"
"jb 201b\t\n"
"jmp 900f\t\n" // exit
// simd no overlap
// counter = -(size/8);
"500:\t\n"
"mov %q[size], %q[counter]\t\n"
"shrq $3, %q[counter]\t\n"
"negq %q[counter]\t\n"
".balign 32\t\n"
"501:\t\n"
"movups (%q[src], %q[i], 4), %%xmm0\t\n"
"movups 16(%q[src], %q[i], 4), %%xmm1\t\n"
"movups %%xmm0, (%q[dst], %q[i], 4)\t\n"
"movups %%xmm1, 16(%q[dst], %q[i], 4)\t\n"
"addq $8, %q[i]\t\n"
"incq %q[counter]\t\n"
"jnz 501b\t\n"
// if (i == size)
"cmpq %q[size], %q[i]\t\n"
"je 900f\t\n" // end
"jmp 100b\t\n" // backporch
"900:\t\n"
: [i] "=&c" (i), [counter] "=&r" (counter), [tmp] "=&a" (tmp), [tmp2] "=&r" (tmp2)
: [dst] "D" (dst), [src] "S" (src), [size] "r" (size)
: "xmm0", "xmm1");
}
JSC_DECLARE_JIT_OPERATION(operationFastForwardCopy32, void, (uint32_t*, const uint32_t*, size_t));
#endif
} } // namespace JSC::B3
#endif // ENABLE(B3_JIT)
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