[PATCH] etnaviv: fix shader miscompilation with more than 16 labels

[Lucas Stach]

Am Montag, den 26.06.2017, 13:40 +0200 schrieb Lucas Stach:
> The labels array may change its virtual address on a reallocation, so
> it is invalid to cache pointers into the array. Rather than using the
> pointer directly, remember the array index.
> 
> Fixes miscompilation of shaders in glmark2 ideas, leading to GPU
> hangs.

Forgot to add: the change seems straightforward enough to CC it to the
stable trees.

> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  src/gallium/drivers/etnaviv/etnaviv_compiler.c | 57 ++++++++++++++
> ------------
>  1 file changed, 30 insertions(+), 27 deletions(-)
> 
> diff --git a/src/gallium/drivers/etnaviv/etnaviv_compiler.c
> b/src/gallium/drivers/etnaviv/etnaviv_compiler.c
> index eafb511bb813..8883e39cf4b3 100644
> --- a/src/gallium/drivers/etnaviv/etnaviv_compiler.c
> +++ b/src/gallium/drivers/etnaviv/etnaviv_compiler.c
> @@ -119,10 +119,10 @@ enum etna_compile_frame_type {
>   */
>  struct etna_compile_frame {
>     enum etna_compile_frame_type type;
> -   struct etna_compile_label *lbl_else;
> -   struct etna_compile_label *lbl_endif;
> -   struct etna_compile_label *lbl_loop_bgn;
> -   struct etna_compile_label *lbl_loop_end;
> +   int lbl_else_idx;
> +   int lbl_endif_idx;
> +   int lbl_loop_bgn_idx;
> +   int lbl_loop_end_idx;
>  };
>  
>  struct etna_compile_file {
> @@ -178,7 +178,7 @@ struct etna_compile {
>     /* Fields for handling nested conditionals */
>     struct etna_compile_frame frame_stack[ETNA_MAX_DEPTH];
>     int frame_sp;
> -   struct etna_compile_label *lbl_usage[ETNA_MAX_INSTRUCTIONS];
> +   int lbl_usage[ETNA_MAX_INSTRUCTIONS];
>  
>     unsigned labels_count, labels_sz;
>     struct etna_compile_label *labels;
> @@ -990,7 +990,7 @@ etna_src_uniforms_conflict(struct etna_inst_src
> a, struct etna_inst_src b)
>  }
>  
>  /* create a new label */
> -static struct etna_compile_label *
> +static unsigned int
>  alloc_new_label(struct etna_compile *c)
>  {
>     struct etna_compile_label label = {
> @@ -999,7 +999,7 @@ alloc_new_label(struct etna_compile *c)
>  
>     array_insert(c->labels, label);
>  
> -   return &c->labels[c->labels_count - 1];
> +   return c->labels_count - 1;
>  }
>  
>  /* place label at current instruction pointer */
> @@ -1015,10 +1015,10 @@ label_place(struct etna_compile *c, struct
> etna_compile_label *label)
>   * as the value becomes known.
>   */
>  static void
> -label_mark_use(struct etna_compile *c, struct etna_compile_label
> *label)
> +label_mark_use(struct etna_compile *c, int lbl_idx)
>  {
>     assert(c->inst_ptr < ETNA_MAX_INSTRUCTIONS);
> -   c->lbl_usage[c->inst_ptr] = label;
> +   c->lbl_usage[c->inst_ptr] = lbl_idx;
>  }
>  
>  /* walk the frame stack and return first frame with matching type */
> @@ -1099,8 +1099,8 @@ trans_if(const struct instr_translater *t,
> struct etna_compile *c,
>     /* push IF to stack */
>     f->type = ETNA_COMPILE_FRAME_IF;
>     /* create "else" label */
> -   f->lbl_else = alloc_new_label(c);
> -   f->lbl_endif = NULL;
> +   f->lbl_else_idx = alloc_new_label(c);
> +   f->lbl_endif_idx = -1;
>  
>     /* We need to avoid the emit_inst() below becoming two
> instructions */
>     if (etna_src_uniforms_conflict(src[0], imm_0))
> @@ -1108,7 +1108,7 @@ trans_if(const struct instr_translater *t,
> struct etna_compile *c,
>  
>     /* mark position in instruction stream of label reference so that
> it can be
>      * filled in in next pass */
> -   label_mark_use(c, f->lbl_else);
> +   label_mark_use(c, f->lbl_else_idx);
>  
>     /* create conditional branch to label if src0 EQ 0 */
>     emit_inst(c, &(struct etna_inst){
> @@ -1129,8 +1129,8 @@ trans_else(const struct instr_translater *t,
> struct etna_compile *c,
>     assert(f->type == ETNA_COMPILE_FRAME_IF);
>  
>     /* create "endif" label, and branch to endif label */
> -   f->lbl_endif = alloc_new_label(c);
> -   label_mark_use(c, f->lbl_endif);
> +   f->lbl_endif_idx = alloc_new_label(c);
> +   label_mark_use(c, f->lbl_endif_idx);
>     emit_inst(c, &(struct etna_inst) {
>        .opcode = INST_OPCODE_BRANCH,
>        .cond = INST_CONDITION_TRUE,
> @@ -1138,7 +1138,7 @@ trans_else(const struct instr_translater *t,
> struct etna_compile *c,
>     });
>  
>     /* mark "else" label at this position in instruction stream */
> -   label_place(c, f->lbl_else);
> +   label_place(c, &c->labels[f->lbl_else_idx]);
>  }
>  
>  static void
> @@ -1151,10 +1151,10 @@ trans_endif(const struct instr_translater *t,
> struct etna_compile *c,
>  
>     /* assign "endif" or "else" (if no ELSE) label to current
> position in
>      * instruction stream, pop IF */
> -   if (f->lbl_endif != NULL)
> -      label_place(c, f->lbl_endif);
> +   if (f->lbl_endif_idx != -1)
> +      label_place(c, &c->labels[f->lbl_endif_idx]);
>     else
> -      label_place(c, f->lbl_else);
> +      label_place(c, &c->labels[f->lbl_else_idx]);
>  }
>  
>  static void
> @@ -1166,10 +1166,10 @@ trans_loop_bgn(const struct instr_translater
> *t, struct etna_compile *c,
>  
>     /* push LOOP to stack */
>     f->type = ETNA_COMPILE_FRAME_LOOP;
> -   f->lbl_loop_bgn = alloc_new_label(c);
> -   f->lbl_loop_end = alloc_new_label(c);
> +   f->lbl_loop_bgn_idx = alloc_new_label(c);
> +   f->lbl_loop_end_idx = alloc_new_label(c);
>  
> -   label_place(c, f->lbl_loop_bgn);
> +   label_place(c, &c->labels[f->lbl_loop_bgn_idx]);
>  
>     c->num_loops++;
>  }
> @@ -1185,7 +1185,7 @@ trans_loop_end(const struct instr_translater
> *t, struct etna_compile *c,
>  
>     /* mark position in instruction stream of label reference so that
> it can be
>      * filled in in next pass */
> -   label_mark_use(c, f->lbl_loop_bgn);
> +   label_mark_use(c, f->lbl_loop_bgn_idx);
>  
>     /* create branch to loop_bgn label */
>     emit_inst(c, &(struct etna_inst) {
> @@ -1195,7 +1195,7 @@ trans_loop_end(const struct instr_translater
> *t, struct etna_compile *c,
>        /* imm is filled in later */
>     });
>  
> -   label_place(c, f->lbl_loop_end);
> +   label_place(c, &c->labels[f->lbl_loop_end_idx]);
>  }
>  
>  static void
> @@ -1207,7 +1207,7 @@ trans_brk(const struct instr_translater *t,
> struct etna_compile *c,
>  
>     /* mark position in instruction stream of label reference so that
> it can be
>      * filled in in next pass */
> -   label_mark_use(c, f->lbl_loop_end);
> +   label_mark_use(c, f->lbl_loop_end_idx);
>  
>     /* create branch to loop_end label */
>     emit_inst(c, &(struct etna_inst) {
> @@ -1227,7 +1227,7 @@ trans_cont(const struct instr_translater *t,
> struct etna_compile *c,
>  
>     /* mark position in instruction stream of label reference so that
> it can be
>      * filled in in next pass */
> -   label_mark_use(c, f->lbl_loop_bgn);
> +   label_mark_use(c, f->lbl_loop_bgn_idx);
>  
>     /* create branch to loop_end label */
>     emit_inst(c, &(struct etna_inst) {
> @@ -1998,8 +1998,9 @@ static void
>  etna_compile_fill_in_labels(struct etna_compile *c)
>  {
>     for (int idx = 0; idx < c->inst_ptr; ++idx) {
> -      if (c->lbl_usage[idx])
> -         etna_assemble_set_imm(&c->code[idx * 4], c->lbl_usage[idx]-
> >inst_idx);
> +      if (c->lbl_usage[idx] != -1)
> +         etna_assemble_set_imm(&c->code[idx * 4],
> +                               c->labels[c-
> >lbl_usage[idx]].inst_idx);
>     }
>  }
>  
> @@ -2301,6 +2302,8 @@ etna_compile_shader(struct etna_shader_variant
> *v)
>     if (!c)
>        return false;
>  
> +   memset(&c->lbl_usage, -1, ARRAY_SIZE(c->lbl_usage));
> +
>     const struct tgsi_token *tokens = v->shader->tokens;
>  
>     c->specs = specs;