[Mesa-dev] [PATCH shader-db] run: don't use alloca to avoid random crashes in the GLSL compiler

[Ilia Mirkin]

What's wrong with feeding it stack memory?

On Wed, Dec 7, 2016 at 12:33 PM, Marek Olšák <maraeo at gmail.com> wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> ---
>  run.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/run.c b/run.c
> index 08fd543..ded224a 100644
> --- a/run.c
> +++ b/run.c
> @@ -656,28 +656,32 @@ main(int argc, char **argv)
>
>              /* If there's only one GLSL shader, mark it separable so
>               * inputs and outputs aren't eliminated.
>               */
>              if (num_shaders == 1 && type != TYPE_VP && type != TYPE_FP)
>                  use_separate_shader_objects = true;
>
>              if (use_separate_shader_objects) {
>                  for (unsigned i = 0; i < num_shaders; i++) {
>                      const char *const_text;
> -                    char *text = alloca(shader[i].length + 1);
> +                    unsigned size = shader[i].length + 1000;
> +                    /* Using alloca crashes in the GLSL compiler.  */
> +                    char *text = malloc(size);
> +                    memset(text, 0, size);
>
>                      /* Make it zero-terminated. */
>                      memcpy(text, shader[i].text, shader[i].length);
>                      text[shader[i].length] = 0;
>
>                      const_text = text;
>                      glCreateShaderProgramv(shader[i].type, 1, &const_text);
> +                    free(text);
>                  }
>              } else if (type == TYPE_CORE || type == TYPE_COMPAT) {
>                  GLuint prog = glCreateProgram();
>
>                  for (unsigned i = 0; i < num_shaders; i++) {
>                      GLuint s = glCreateShader(shader[i].type);
>                      glShaderSource(s, 1, &shader[i].text, &shader[i].length);
>                      glCompileShader(s);
>
>                      GLint param;
> --
> 2.7.4
>
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