intel/compiler: Add id parameter to shader_perf_log callback

There are two problems with the current architecture.

In OpenGL, the id is supposed to be a unique identifier for a particular
log source.  This is done so that applications can (theoretically)
filter particular log messages.  The debug callback infrastructure in
Mesa assigns a uniqe value when a value of 0 is passed in.  This causes
the id to get set once to a unique value for each message.

By passing a stack variable that is initialized to 0 on every call,
every time the same message is logged, it will have a different id.
This isn't great, but it's also not catastrophic.

When threaded shader compiles are used, the id *pointer* is saved and
dereferenced at a possibly much later time on a possibly different
thread.  This causes one thread to access the stack from a different
thread... and that stack frame might not be valid any more. :(

I have not observed any crashes related to this particular issue.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12136>

2 files changed, 4 insertions, 5 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_program.c b/src/mesa/drivers/dri/i965/brw_program.c
index 0265fd73ea0..4cf5172e16d 100644
--- a/src/mesa/drivers/dri/i965/brw_program.c
+++ b/src/mesa/drivers/dri/i965/brw_program.c
@@ -964,8 +964,8 @@ brw_debug_recompile(struct brw_context *brw,
    const struct brw_compiler *compiler = brw->screen->compiler;
    enum brw_cache_id cache_id = brw_stage_cache_id(stage);
 
-   compiler->shader_perf_log(brw, "Recompiling %s shader for program %d\n",
-                             _mesa_shader_stage_to_string(stage), api_id);
+   brw_shader_perf_log(compiler, brw, "Recompiling %s shader for program %d\n",
+                       _mesa_shader_stage_to_string(stage), api_id);
 
    const void *old_key =
       brw_find_previous_compile(&brw->cache, cache_id, key->program_string_id);
diff --git a/src/mesa/drivers/dri/i965/brw_screen.c b/src/mesa/drivers/dri/i965/brw_screen.c
index 20ca5c21451..4c5bc64a4a5 100644
--- a/src/mesa/drivers/dri/i965/brw_screen.c
+++ b/src/mesa/drivers/dri/i965/brw_screen.c
@@ -2486,7 +2486,7 @@ shader_debug_log_mesa(void *data, unsigned *msg_id, const char *fmt, ...)
 }
 
 static void
-shader_perf_log_mesa(void *data, const char *fmt, ...)
+shader_perf_log_mesa(void *data, unsigned *msg_id, const char *fmt, ...)
 {
    struct brw_context *brw = (struct brw_context *)data;
 
@@ -2501,8 +2501,7 @@ shader_perf_log_mesa(void *data, const char *fmt, ...)
    }
 
    if (brw->perf_debug) {
-      GLuint msg_id = 0;
-      _mesa_gl_vdebugf(&brw->ctx, &msg_id,
+      _mesa_gl_vdebugf(&brw->ctx, msg_id,
                        MESA_DEBUG_SOURCE_SHADER_COMPILER,
                        MESA_DEBUG_TYPE_PERFORMANCE,
                        MESA_DEBUG_SEVERITY_MEDIUM, fmt, args);