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nir/spirv: Handle builtins in OpAccessChain

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Previously, we were trying to handle them later when loading.  However, at
that point, you've already lost information and it's harder to handle
certain corner-cases.  In particular, if you have a shader that does

gl_PerVertex.gl_Position.x = foo

we have trouble because we see the .x and we don't know that we're in
gl_Position.  If we, instead, handle it in OpAccessChain, we have all the
information we need and we can silently re-direct it to the appropreate
variable.  This also lets us delete some code which is a nice side-effect.
This commit is contained in:
Jason Ekstrand
2015-10-19 15:50:45 -07:00
parent 958fc04dc5
commit 7e6959402d
1 changed files with 12 additions and 49 deletions
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src/glsl/nir/spirv_to_nir.c
+12 -49
View File
@@ -854,44 +854,6 @@ get_builtin_variable(struct vtn_builder *b,
return var;
}
static void
vtn_builtin_load(struct vtn_builder *b,
struct vtn_ssa_value *val,
SpvBuiltIn builtin)
{
assert(glsl_type_is_vector_or_scalar(val->type));
nir_variable *var = get_builtin_variable(b, val->type, builtin);
nir_intrinsic_instr *load =
nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_var);
nir_ssa_dest_init(&load->instr, &load->dest,
glsl_get_vector_elements(val->type), NULL);
load->variables[0] = nir_deref_var_create(load, var);
load->num_components = glsl_get_vector_elements(val->type);
nir_builder_instr_insert(&b->nb, &load->instr);
val->def = &load->dest.ssa;
}
static void
vtn_builtin_store(struct vtn_builder *b,
struct vtn_ssa_value *val,
SpvBuiltIn builtin)
{
assert(glsl_type_is_vector_or_scalar(val->type));
nir_variable *var = get_builtin_variable(b, val->type, builtin);
nir_intrinsic_instr *store =
nir_intrinsic_instr_create(b->shader, nir_intrinsic_store_var);
store->variables[0] = nir_deref_var_create(store, var);
store->num_components = glsl_get_vector_elements(val->type);
store->src[0] = nir_src_for_ssa(val->def);
nir_builder_instr_insert(&b->nb, &store->instr);
}
static struct vtn_ssa_value *
_vtn_variable_load(struct vtn_builder *b,
nir_deref_var *src_deref, struct vtn_type *src_type,
@@ -900,11 +862,6 @@ _vtn_variable_load(struct vtn_builder *b,
struct vtn_ssa_value *val = rzalloc(b, struct vtn_ssa_value);
val->type = src_deref_tail->type;
if (src_type->is_builtin) {
vtn_builtin_load(b, val, src_type->builtin);
return val;
}
/* The deref tail may contain a deref to select a component of a vector (in
* other words, it might not be an actual tail) so we have to save it away
* here since we overwrite it later.
@@ -976,11 +933,6 @@ _vtn_variable_store(struct vtn_builder *b, struct vtn_type *dest_type,
nir_deref_var *dest_deref, nir_deref *dest_deref_tail,
struct vtn_ssa_value *src)
{
if (dest_type->is_builtin) {
vtn_builtin_store(b, src, dest_type->builtin);
return;
}
nir_deref *old_child = dest_deref_tail->child;
if (glsl_type_is_vector_or_scalar(src->type)) {
@@ -1410,7 +1362,18 @@ vtn_handle_variables(struct vtn_builder *b, SpvOp opcode,
default:
unreachable("Invalid type for deref");
}
tail = tail->child;
if (deref_type->is_builtin) {
/* If we encounter a builtin, we throw away the ress of the
* access chain, jump to the builtin, and keep building.
*/
nir_variable *builtin = get_builtin_variable(b, deref_type->type,
deref_type->builtin);
val->deref = nir_deref_var_create(b, builtin);
tail = &val->deref->deref;
} else {
tail = tail->child;
}
}
/* For uniform blocks, we don't resolve the access chain until we