[Mesa-dev] [PATCH] nir: fix dangling ssadef->name ptrs

[Jason Ekstrand]

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>

On Tue, Mar 22, 2016 at 12:35 PM, Rob Clark <robdclark at gmail.com> wrote:

> From: Rob Clark <robclark at freedesktop.org>
>
> In many places, the convention is to pass an existing ssadef name ptr
> when construction/initializing a new nir_ssa_def.  But that goes badly
> (as noticed by garbage in nir_print output) when the original string
> gets freed.
>
> Just use ralloc_strdup() instead, and add ralloc_free() in the two
> places that would care (not that the strings wouldn't eventually get
> freed anyways).
>
> Also fixup the nir_search code which was directly setting ssadef->name
> to use the parent instruction as memctx.
>
> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
>  src/compiler/nir/nir.c        | 4 +++-
>  src/compiler/nir/nir_search.c | 6 +++---
>  src/compiler/nir/nir_to_ssa.c | 2 ++
>  3 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/src/compiler/nir/nir.c b/src/compiler/nir/nir.c
> index b114981..20f1a18 100644
> --- a/src/compiler/nir/nir.c
> +++ b/src/compiler/nir/nir.c
> @@ -1317,12 +1317,13 @@ nir_instr_rewrite_dest(nir_instr *instr, nir_dest
> *dest, nir_dest new_dest)
>        src_add_all_uses(dest->reg.indirect, instr, NULL);
>  }
>
> +/* note: does *not* take ownership of 'name' */
>  void
>  nir_ssa_def_init(nir_instr *instr, nir_ssa_def *def,
>                   unsigned num_components,
>                   unsigned bit_size, const char *name)
>  {
> -   def->name = name;
> +   def->name = ralloc_strdup(instr, name);
>     def->parent_instr = instr;
>     list_inithead(&def->uses);
>     list_inithead(&def->if_uses);
> @@ -1339,6 +1340,7 @@ nir_ssa_def_init(nir_instr *instr, nir_ssa_def *def,
>     }
>  }
>
> +/* note: does *not* take ownership of 'name' */
>  void
>  nir_ssa_dest_init(nir_instr *instr, nir_dest *dest,
>                   unsigned num_components, unsigned bit_size,
> diff --git a/src/compiler/nir/nir_search.c b/src/compiler/nir/nir_search.c
> index 6df662a..842ff65 100644
> --- a/src/compiler/nir/nir_search.c
> +++ b/src/compiler/nir/nir_search.c
> @@ -464,7 +464,7 @@ construct_value(const nir_search_value *value,
>
>        switch (c->type) {
>        case nir_type_float:
> -         load->def.name = ralloc_asprintf(mem_ctx, "%f", c->data.d);
> +         load->def.name = ralloc_asprintf(load, "%f", c->data.d);
>           switch (bitsize->dest_size) {
>           case 32:
>              load->value.f32[0] = c->data.d;
> @@ -478,7 +478,7 @@ construct_value(const nir_search_value *value,
>           break;
>
>        case nir_type_int:
> -         load->def.name = ralloc_asprintf(mem_ctx, "%ld", c->data.i);
> +         load->def.name = ralloc_asprintf(load, "%ld", c->data.i);
>           switch (bitsize->dest_size) {
>           case 32:
>              load->value.i32[0] = c->data.i;
> @@ -492,7 +492,7 @@ construct_value(const nir_search_value *value,
>           break;
>
>        case nir_type_uint:
> -         load->def.name = ralloc_asprintf(mem_ctx, "%lu", c->data.u);
> +         load->def.name = ralloc_asprintf(load, "%lu", c->data.u);
>           switch (bitsize->dest_size) {
>           case 32:
>              load->value.u32[0] = c->data.u;
> diff --git a/src/compiler/nir/nir_to_ssa.c b/src/compiler/nir/nir_to_ssa.c
> index 0640607..d588d7d 100644
> --- a/src/compiler/nir/nir_to_ssa.c
> +++ b/src/compiler/nir/nir_to_ssa.c
> @@ -221,6 +221,7 @@ rewrite_def_forwards(nir_dest *dest, void *_state)
>     list_del(&dest->reg.def_link);
>     nir_ssa_dest_init(state->parent_instr, dest, reg->num_components,
>                       reg->bit_size, name);
> +   ralloc_free(name);
>
>     /* push our SSA destination on the stack */
>     state->states[index].index++;
> @@ -274,6 +275,7 @@ rewrite_alu_instr_forward(nir_alu_instr *instr,
> rewrite_state *state)
>        list_del(&instr->dest.dest.reg.def_link);
>        nir_ssa_dest_init(&instr->instr, &instr->dest.dest, num_components,
>                          reg->bit_size, name);
> +      ralloc_free(name);
>
>        if (nir_op_infos[instr->op].output_size == 0) {
>           /*
> --
> 2.5.0
>
>
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