nir: fix use-after-free on function parameter names

Fixes: 3da8444be5 ("nir: add names to function parameters")
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Acked-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35098>

src/compiler/nir/nir_serialize.c

@@ -2060,8 +2060,10 @@ read_function(read_ctx *ctx)
    for (unsigned i = 0; i < fxn->num_params; i++) {
       uint32_t val = blob_read_uint32(ctx->blob);
       bool has_name = (val & 0x10000);
-      if (has_name)
-         fxn->params[i].name = blob_read_string(ctx->blob);
+      if (has_name) {
+         char *name = blob_read_string(ctx->blob);
+         fxn->params[i].name = ralloc_strdup(ctx->nir, name);
+      }
 
       fxn->params[i].num_components = val & 0xff;
       fxn->params[i].bit_size = (val >> 8) & 0xff;

src/compiler/nir/nir_sweep.c

@@ -140,6 +140,9 @@ sweep_function(nir_shader *nir, nir_function *f)
    ralloc_steal(nir, f);
    ralloc_steal(nir, f->params);
 
+   for (unsigned i = 0; i < f->num_params; i++)
+      ralloc_steal(nir, (char *)f->params[i].name);
+
    if (f->impl)
       sweep_impl(nir, f->impl);
 }

src/compiler/spirv/vtn_opencl.c

@@ -154,6 +154,7 @@ static nir_function *mangle_and_find(struct vtn_builder *b,
          decl->params = ralloc_array(b->shader, nir_parameter, decl->num_params);
          for (unsigned i = 0; i < decl->num_params; i++) {
             decl->params[i] = found->params[i];
+            decl->params[i].name = ralloc_strdup(b->shader, found->params[i].name);
          }
          found = decl;
       }