450ec38d79
noop-renderer needs to actually access the buffer content, to ensure
that the bad-buffer test works. This was previously done using a
volatile variable, but clang rightly pointed out that the variable
access had no effect (since the volatile stack variable was never read
from, and the source is not volatile), so 9b0b5b57dd changed it to be
explicitly marked it as unused to suppress the compiler warning.
Unfortunately suppressing the warning still leaves the compiler free to
optimise out the access.
Replace the variable decorations with actually using the result of the
read, so we can be really sure that it's never going to be optimised
away.
Signed-off-by: Daniel Stone <daniels@collabora.com>
134 lines
3.8 KiB
C
134 lines
3.8 KiB
C
/*
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* Copyright © 2012 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a 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, sublicense, 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
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* portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "config.h"
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#include <stdint.h>
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#include <stdlib.h>
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#include <libweston/libweston.h>
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#include "libweston-internal.h"
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struct noop_renderer {
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struct weston_renderer base;
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unsigned char seed; /* see comment in attach() */
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};
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static int
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noop_renderer_read_pixels(struct weston_output *output,
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pixman_format_code_t format, void *pixels,
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uint32_t x, uint32_t y,
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uint32_t width, uint32_t height)
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{
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return 0;
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}
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static void
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noop_renderer_repaint_output(struct weston_output *output,
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pixman_region32_t *output_damage)
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{
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}
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static void
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noop_renderer_flush_damage(struct weston_surface *surface,
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struct weston_buffer *buffer)
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{
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}
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static void
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noop_renderer_attach(struct weston_surface *es, struct weston_buffer *buffer)
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{
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struct noop_renderer *renderer =
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wl_container_of(es->compositor->renderer, renderer, base);
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struct wl_shm_buffer *shm_buffer;
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uint8_t *data;
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uint32_t size, i, height, stride;
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unsigned char unused = 0;
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if (!buffer)
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return;
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switch (buffer->type) {
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case WESTON_BUFFER_SOLID:
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/* no-op, early exit */
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return;
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case WESTON_BUFFER_SHM:
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/* fine */
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break;
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default:
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weston_log("No-op renderer supports only SHM buffers\n");
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return;
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}
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shm_buffer = buffer->shm_buffer;
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data = wl_shm_buffer_get_data(shm_buffer);
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stride = wl_shm_buffer_get_stride(shm_buffer);
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height = buffer->height;
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size = stride * height;
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/* Access the buffer data to make sure the buffer's client gets killed
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* if the buffer size is invalid. This makes the bad_buffer test pass.
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* This can be removed if we start reading the buffer contents
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* somewhere else, e.g. in repaint_output(). */
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wl_shm_buffer_begin_access(shm_buffer);
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for (i = 0; i < size; i++)
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unused ^= data[i];
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wl_shm_buffer_end_access(shm_buffer);
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/* Make sure that our unused is actually used, otherwise the compiler
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* is free to notice that our reads have no effect and elide them. */
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renderer->seed = unused;
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}
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static void
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noop_renderer_destroy(struct weston_compositor *ec)
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{
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struct noop_renderer *renderer =
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wl_container_of(ec->renderer, renderer, base);
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weston_log("no-op renderer SHM seed: %d\n", renderer->seed);
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free(ec->renderer);
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ec->renderer = NULL;
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}
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WL_EXPORT int
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noop_renderer_init(struct weston_compositor *ec)
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{
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struct noop_renderer *renderer;
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renderer = zalloc(sizeof *renderer);
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if (renderer == NULL)
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return -1;
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renderer->base.read_pixels = noop_renderer_read_pixels;
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renderer->base.repaint_output = noop_renderer_repaint_output;
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renderer->base.flush_damage = noop_renderer_flush_damage;
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renderer->base.attach = noop_renderer_attach;
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renderer->base.destroy = noop_renderer_destroy;
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ec->renderer = &renderer->base;
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return 0;
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}
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