[Mesa-dev] [PATCH] mesa: if MESA_DEBUG=context, create a debug context

[Brian Paul]

On 11/17/2016 08:22 AM, Gustaw Smolarczyk wrote:
> 2016-11-16 0:05 GMT+01:00 Brian Paul <brianp at vmware.com
> <mailto:brianp at vmware.com>>:
>
>     A number of drivers report useful debug/perf information accessible
>     through GL_ARB_debug_output and with debug contexts (i.e. setting the
>     GLX_CONTEXT_DEBUG_BIT_ARB flag).  But few applications actually use
>     the GL_ARB_debug_output extension.
>
>     This change lets one set the MESA_DEBUG env var to "context" to
>     force-set
>     a debug context and report debug/perf messages to stderr (or whatever
>     file MESA_LOG_FILE is set to).  This is a useful debugging tool.
>
>     The small change in st_api_create_context() is needed so that
>     st_update_debug_callback() gets called to hook up the driver debug
>     callbacks when ST_CONTEXT_FLAG_DEBUG was not set, but
>     MESA_DEBUG=context.
>     ---
>       src/mesa/main/debug.c               |  3 ++-
>       src/mesa/main/debug_output.c        | 28 ++++++++++++++++++++++++++++
>       src/mesa/main/mtypes.h              |  3 ++-
>       src/mesa/state_tracker/st_manager.c |  2 ++
>       4 files changed, 34 insertions(+), 2 deletions(-)
>
>     diff --git a/src/mesa/main/debug.c b/src/mesa/main/debug.c
>     index 5ca7d5c..3471b26 100644
>     --- a/src/mesa/main/debug.c
>     +++ b/src/mesa/main/debug.c
>     @@ -189,7 +189,8 @@ set_debug_flags(const char *str)
>             { "silent", DEBUG_SILENT }, /* turn off debug messages */
>             { "flush", DEBUG_ALWAYS_FLUSH }, /* flush after each drawing
>     command */
>             { "incomplete_tex", DEBUG_INCOMPLETE_TEXTURE },
>     -      { "incomplete_fbo", DEBUG_INCOMPLETE_FBO }
>     +      { "incomplete_fbo", DEBUG_INCOMPLETE_FBO },
>     +      { "context", DEBUG_CONTEXT } /* force set
>     GL_CONTEXT_FLAG_DEBUG_BIT flag */
>          };
>          GLuint i;
>
>     diff --git a/src/mesa/main/debug_output.c b/src/mesa/main/debug_output.c
>     index 85f64bd..290d626 100644
>     --- a/src/mesa/main/debug_output.c
>     +++ b/src/mesa/main/debug_output.c
>     @@ -99,6 +99,7 @@ struct gl_debug_state
>          const void *CallbackData;
>          GLboolean SyncOutput;
>          GLboolean DebugOutput;
>     +   GLboolean LogToStderr;
>
>          struct gl_debug_group *Groups[MAX_DEBUG_GROUP_STACK_DEPTH];
>          struct gl_debug_message GroupMessages[MAX_DEBUG_GROUP_STACK_DEPTH];
>     @@ -617,6 +618,17 @@ debug_log_message(struct gl_debug_state *debug,
>          GLint nextEmpty;
>          struct gl_debug_message *emptySlot;
>
>     +   if (debug->LogToStderr) {
>     +      /* since 'buf' is not null terminated, make a copy and add \0 */
>     +      char *buf2 = malloc(len + 1);
>     +      if (buf2) {
>     +         memcpy(buf2, buf, len);
>     +         buf2[len] = 0;
>     +         _mesa_log("Mesa debug output: %s\n", buf2);
>     +         free(buf2);
>     +      }
>     +   }
>     +
>          assert(len < MAX_DEBUG_MESSAGE_LENGTH);
>
>          if (log->NumMessages == MAX_DEBUG_LOGGED_MESSAGES)
>     @@ -845,6 +857,7 @@ log_msg_locked_and_unlock(struct gl_context *ctx,
>          }
>
>          if (ctx->Debug->Callback) {
>     +      /* Call the user's callback function */
>             GLenum gl_source = debug_source_enums[source];
>             GLenum gl_type = debug_type_enums[type];
>             GLenum gl_severity = debug_severity_enums[severity];
>     @@ -860,6 +873,7 @@ log_msg_locked_and_unlock(struct gl_context *ctx,
>             callback(gl_source, gl_type, id, gl_severity, len, buf, data);
>          }
>          else {
>     +      /* add debug message to queue */
>             debug_log_message(ctx->Debug, source, type, id, severity,
>     len, buf);
>             _mesa_unlock_debug_state(ctx);
>          }
>     @@ -1267,6 +1281,20 @@ void
>       _mesa_init_debug_output(struct gl_context *ctx)
>       {
>          mtx_init(&ctx->DebugMutex, mtx_plain);
>     +
>     +   if (MESA_DEBUG_FLAGS & DEBUG_CONTEXT) {
>     +      /* If the MESA_DEBUG env is set to "context", we'll turn on the
>     +       * GL_CONTEXT_FLAG_DEBUG_BIT context flag and log debug output
>     +       * messages to stderr (or whatever MESA_LOG_FILE points at).
>     +       */
>     +      struct gl_debug_state *debug = _mesa_lock_debug_state(ctx);
>     +      if (!debug) {
>     +         return;
>     +      }
>     +      debug->DebugOutput = GL_TRUE;
>     +      debug->LogToStderr = GL_TRUE;
>     +      ctx->Const.ContextFlags |= GL_CONTEXT_FLAG_DEBUG_BIT;
>
>
> Don't we want to perform an _mesa_unlock_debug_state(ctx); here?

Tom posted a patch for that yesterday.  Not sure if it landed yet.

-Brian