[igt-dev] [PATCH i-g-t v2] tools/i915-perf: workaround overzelous compiler warnings

[Lionel Landwerlin]

On 21/02/2020 12:09, Petri Latvala wrote:
> On Thu, Feb 20, 2020 at 03:34:16PM +0200, Lionel Landwerlin wrote:
>> Take 2.
>>
>> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
>> ---
>>   tools/i915-perf/i915_perf_recorder_commands.h | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/i915-perf/i915_perf_recorder_commands.h b/tools/i915-perf/i915_perf_recorder_commands.h
>> index 4855d80f..44dd4438 100644
>> --- a/tools/i915-perf/i915_perf_recorder_commands.h
>> +++ b/tools/i915-perf/i915_perf_recorder_commands.h
>> @@ -35,5 +35,6 @@ struct recorder_command_base {
>>   };
>>   
>>   struct recorder_command_dump {
>> -	uint8_t path[0];
>> +	uint8_t unused;
>> +	uint8_t path[];
>>   };
> And now all your mallocs need + 1.


You're right, I forgot the sizeof(struct recorder_command_dump).


>
> Why do you insist on having two structs?


I want the person reading this code to understand what the packets 
exchanged look like.


>   The recorder_command_dump
> struct only acts as "here be an array" object and you don't do
> anything to it as an object anywhere.
>
> A drive-by note, i915_perf_recorder_commands.h lacks include guards.
>
>
>
> diff --git a/tools/i915-perf/i915_perf_control.c b/tools/i915-perf/i915_perf_control.c
> index a8d0d30f..be5996c0 100644
> --- a/tools/i915-perf/i915_perf_control.c
> +++ b/tools/i915-perf/i915_perf_control.c
> @@ -93,12 +93,12 @@ main(int argc, char *argv[])
>   				sizeof(struct recorder_command_base) + strlen(dump_file) + 1;
>   			struct {
>   				struct recorder_command_base base;
> -				struct recorder_command_dump dump;
> +				uint8_t dump[];
>   			} *data = malloc(total_len);
>   
>   			data->base.command = RECORDER_COMMAND_DUMP;
>   			data->base.size = total_len;
> -			snprintf((char *) data->dump.path, strlen(dump_file) + 1, "%s", dump_file);
> +			snprintf((char *) data->dump, strlen(dump_file) + 1, "%s", dump_file);
>   
>   			fwrite(data, total_len, 1, command_fifo_file);
>   		} else {
> @@ -107,12 +107,12 @@ main(int argc, char *argv[])
>   			uint32_t total_len = sizeof(struct recorder_command_base) + path_len;
>   			struct {
>   				struct recorder_command_base base;
> -				struct recorder_command_dump dump;
> +				uint8_t dump[];
>   			} *data = malloc(total_len);
>   
>   			data->base.command = RECORDER_COMMAND_DUMP;
>   			data->base.size = total_len;
> -			snprintf((char *) data->dump.path, path_len, "%s/%s", cwd, dump_file);
> +			snprintf((char *) data->dump, path_len, "%s/%s", cwd, dump_file);
>   
>   			fwrite(data, total_len, 1, command_fifo_file);
>   		}
> diff --git a/tools/i915-perf/i915_perf_recorder.c b/tools/i915-perf/i915_perf_recorder.c
> index 760cabf1..6bbc451e 100644
> --- a/tools/i915-perf/i915_perf_recorder.c
> +++ b/tools/i915-perf/i915_perf_recorder.c
> @@ -605,7 +605,7 @@ read_command_file(struct recording_context *ctx)
>   	switch (header.command) {
>   	case RECORDER_COMMAND_DUMP: {
>   		uint32_t len = header.size - sizeof(header), offset = 0;
> -		struct recorder_command_dump *dump = malloc(len);
> +		uint8_t *dump = malloc(len);
>   		FILE *file;
>   
>   		while (offset < len &&
> @@ -616,9 +616,9 @@ read_command_file(struct recording_context *ctx)
>   				offset += ret;
>   		}
>   
> -		fprintf(stdout, "Writing circular buffer to %s\n", dump->path);
> +		fprintf(stdout, "Writing circular buffer to %s\n", dump);
>   
> -		file = fopen((const char *) dump->path, "w+");
> +		file = fopen((const char *) dump, "w+");
>   		if (file) {
>   			struct chunk chunks[2];
>   
> @@ -634,11 +634,11 @@ read_command_file(struct recording_context *ctx)
>   			     fwrite(chunks[1].data, chunks[1].len, 1, file) != 1) ||
>   			    !write_correlation_timestamps(file, ctx->drm_fd)) {
>   				fprintf(stderr, "Unable to write circular buffer data in file '%s'\n",
> -					dump->path);
> +					dump);
>   			}
>   			fclose(file);
>   		} else
> -			fprintf(stderr, "Unable to write dump file '%s'\n", dump->path);
> +			fprintf(stderr, "Unable to write dump file '%s'\n", dump);
>   
>   		free(dump);
>   		break;
> diff --git a/tools/i915-perf/i915_perf_recorder_commands.h b/tools/i915-perf/i915_perf_recorder_commands.h
> index 4855d80f..3db11327 100644
> --- a/tools/i915-perf/i915_perf_recorder_commands.h
> +++ b/tools/i915-perf/i915_perf_recorder_commands.h
> @@ -33,7 +33,3 @@ struct recorder_command_base {
>   	uint32_t command;
>   	uint32_t size;
>   };
> -
> -struct recorder_command_dump {
> -	uint8_t path[0];
> -};
>
Can you leave this structure in there but commented?

Just so that there is a trace of what you is exchanged between the 2 
processes.


Thanks,


-Lionel