1b8a43a0ba
util_cpu_detect is an anti-pattern: it relies on callers high up in the call chain initializing a local implementation detail. As a real example, I added: ...a Mali compiler unit test ...that called bi_imm_f16() to construct an FP16 immediate ...that calls _mesa_float_to_half internally ...that calls util_get_cpu_caps internally, but only on x86_64! ...that relies on util_cpu_detect having been called before. As a consequence, this unit test: ...crashes on x86_64 with USE_X86_64_ASM set ...passes on every other architecture ...works on my local arm64 workstation and on my test board ...failed CI which runs on x86_64 ...needed to have a random util_cpu_detect() call sprinkled in. This is a bad design decision. It pollutes the tree with magic, it causes mysterious CI failures especially for non-x86_64 developers, and it is not justified by a micro-optimization. Instead, let's call util_cpu_detect directly from util_get_cpu_caps, avoiding the footgun where it fails to be called. This cleans up Mesa's design, simplifies the tree, and avoids a class of a (possibly platform-specific) failures. To mitigate the added overhead, wrap it all in a (fast) atomic load check and declare the whole thing as ATTRIBUTE_CONST so the compiler will CSE calls to util_cpu_detect. Co-authored-by: Alyssa Rosenzweig <alyssa@collabora.com> Reviewed-by: Marek Olšák <maraeo@gmail.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15580>
67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
/**************************************************************************
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*
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* Copyright 2008 VMware, Inc.
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
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* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
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* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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**************************************************************************/
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#include "pipe/p_config.h"
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#include "rtasm_cpu.h"
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#if defined(PIPE_ARCH_X86) || defined(PIPE_ARCH_X86_64)
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#include "util/u_debug.h"
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#include "util/u_cpu_detect.h"
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DEBUG_GET_ONCE_BOOL_OPTION(nosse, "GALLIUM_NOSSE", false);
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static const struct util_cpu_caps_t *get_cpu_caps(void)
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{
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return util_get_cpu_caps();
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}
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int rtasm_cpu_has_sse(void)
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{
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return !debug_get_option_nosse() && get_cpu_caps()->has_sse;
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}
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int rtasm_cpu_has_sse2(void)
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{
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return !debug_get_option_nosse() && get_cpu_caps()->has_sse2;
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}
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#else
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int rtasm_cpu_has_sse(void)
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{
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return 0;
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}
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int rtasm_cpu_has_sse2(void)
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{
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return 0;
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}
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#endif
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