On 27 September 2013 14:32, Ian Romanick <i...@freedesktop.org> wrote:
> There are some bits of this patch I'm trying to understand. I think > they can be cleared up by one question below... > > On 09/14/2013 01:00 PM, Paul Berry wrote: > > From: Bryan Cain <bryanca...@gmail.com> > > > > This corresponds to the lowering of gl_ClipDistance to > > gl_ClipDistanceMESA for vertex and geometry shader outputs. Since > > this lowering pass occurs after lower_named_interface blocks, it deals > > with 2D arrays (gl_ClipDistance[vertex][clip_plane]) rather than 1D > > arrays in an interface block > > (gl_in[vertex].gl_ClipDistance[clip_plane]). > > > > v2 (Paul Berry <stereotype...@gmail.com>): Fix indexing order for > > gl_ClipDistance input lowering. Properly lower bulk assignment of > > gl_ClipDistance inputs. Rework for GLSL 1.50 style geometry shaders. > > --- > > src/glsl/lower_clip_distance.cpp | 223 > +++++++++++++++++++++++++++++---------- > > 1 file changed, 165 insertions(+), 58 deletions(-) > > > > diff --git a/src/glsl/lower_clip_distance.cpp > b/src/glsl/lower_clip_distance.cpp > > index d6cf944..16eaef6 100644 > > --- a/src/glsl/lower_clip_distance.cpp > > +++ b/src/glsl/lower_clip_distance.cpp > > @@ -53,13 +53,16 @@ > > class lower_clip_distance_visitor : public ir_rvalue_visitor { > > public: > > lower_clip_distance_visitor() > > - : progress(false), old_clip_distance_var(NULL), > > - new_clip_distance_var(NULL) > > + : progress(false), old_clip_distance_1d_var(NULL), > > + old_clip_distance_2d_var(NULL), new_clip_distance_1d_var(NULL), > > + new_clip_distance_2d_var(NULL) > > { > > } > > > > virtual ir_visitor_status visit(ir_variable *); > > void create_indices(ir_rvalue*, ir_rvalue *&, ir_rvalue *&); > > + bool is_clip_distance_vec8(ir_rvalue *ir); > > + ir_rvalue *lower_clip_distance_vec8(ir_rvalue *ir); > > virtual ir_visitor_status visit_leave(ir_assignment *); > > void visit_new_assignment(ir_assignment *ir); > > virtual ir_visitor_status visit_leave(ir_call *); > > @@ -73,12 +76,14 @@ public: > > /** > > * Pointer to the declaration of gl_ClipDistance, if found. > > */ > > - ir_variable *old_clip_distance_var; > > + ir_variable *old_clip_distance_1d_var; > > + ir_variable *old_clip_distance_2d_var; > > > > /** > > * Pointer to the newly-created gl_ClipDistanceMESA variable. > > */ > > - ir_variable *new_clip_distance_var; > > + ir_variable *new_clip_distance_1d_var; > > + ir_variable *new_clip_distance_2d_var; > > }; > > > > > > @@ -89,30 +94,60 @@ public: > > ir_visitor_status > > lower_clip_distance_visitor::visit(ir_variable *ir) > > { > > - /* No point in looking for the declaration of gl_ClipDistance if > > - * we've already found it. > > - */ > > - if (this->old_clip_distance_var) > > + if (!ir->name || strcmp(ir->name, "gl_ClipDistance") != 0) > > return visit_continue; > > + assert (ir->type->is_array()); > > + > > + if (!ir->type->element_type()->is_array()) { > > + /* 1D gl_ClipDistance (used for vertex and geometry output, and > fragment > > + * input). > > + */ > > + if (this->old_clip_distance_1d_var) > > + return visit_continue; > > > > - if (ir->name && strcmp(ir->name, "gl_ClipDistance") == 0) { > > this->progress = true; > > - this->old_clip_distance_var = ir; > > - assert (ir->type->is_array()); > > + this->old_clip_distance_1d_var = ir; > > assert (ir->type->element_type() == glsl_type::float_type); > > unsigned new_size = (ir->type->array_size() + 3) / 4; > > > > /* Clone the old var so that we inherit all of its properties */ > > - this->new_clip_distance_var = ir->clone(ralloc_parent(ir), NULL); > > + this->new_clip_distance_1d_var = ir->clone(ralloc_parent(ir), > NULL); > > > > /* And change the properties that we need to change */ > > - this->new_clip_distance_var->name > > - = ralloc_strdup(this->new_clip_distance_var, > "gl_ClipDistanceMESA"); > > - this->new_clip_distance_var->type > > + this->new_clip_distance_1d_var->name > > + = ralloc_strdup(this->new_clip_distance_1d_var, > > + "gl_ClipDistanceMESA"); > > + this->new_clip_distance_1d_var->type > > = glsl_type::get_array_instance(glsl_type::vec4_type, > new_size); > > - this->new_clip_distance_var->max_array_access = > ir->max_array_access / 4; > > + this->new_clip_distance_1d_var->max_array_access > > + = ir->max_array_access / 4; > > + > > + ir->replace_with(this->new_clip_distance_1d_var); > > + } else { > > + /* 2D gl_ClipDistance (used for geometry input). */ > > + assert(ir->mode == ir_var_shader_in); > > + if (this->old_clip_distance_2d_var) > > + return visit_continue; > > > > - ir->replace_with(this->new_clip_distance_var); > > + this->progress = true; > > + this->old_clip_distance_2d_var = ir; > > + assert (ir->type->element_type()->element_type() == > glsl_type::float_type); > > + unsigned new_size = (ir->type->element_type()->array_size() + 3) > / 4; > > + > > + /* Clone the old var so that we inherit all of its properties */ > > + this->new_clip_distance_2d_var = ir->clone(ralloc_parent(ir), > NULL); > > + > > + /* And change the properties that we need to change */ > > + this->new_clip_distance_2d_var->name > > + = ralloc_strdup(this->new_clip_distance_2d_var, > "gl_ClipDistanceMESA"); > > + this->new_clip_distance_2d_var->type = > glsl_type::get_array_instance( > > + glsl_type::get_array_instance(glsl_type::vec4_type, > > + new_size), > > + ir->type->array_size()); > > + this->new_clip_distance_2d_var->max_array_access > > + = ir->max_array_access / 4; > > + > > + ir->replace_with(this->new_clip_distance_2d_var); > > } > > return visit_continue; > > } > > @@ -177,39 +212,99 @@ > lower_clip_distance_visitor::create_indices(ir_rvalue *old_index, > > } > > > > > > +/** > > + * Determine whether the given rvalue describes an array of 8 floats > that > > + * needs to be lowered to an array of 2 vec4's; that is, determine > whether it > > + * matches one of the following patterns: > > + * > > + * - gl_ClipDistance (if gl_ClipDistance is 1D) > > + * - gl_ClipDistance[i] (if gl_ClipDistance is 2D) > > + */ > > +bool > > +lower_clip_distance_visitor::is_clip_distance_vec8(ir_rvalue *ir) > > +{ > > Is it ever possible for both of these to be taken? > Yes. If we are in a geometry shader, then there's both a 1D clip distance variable (for the gl_ClipDistance output) and a 2D clip distance variable (for the gl_in[i].gl_ClipDistance input). Note that this pass runs after lower_named_interface_blocks(), so the clip distance input just looks like a bare 2D array. So if, for example, ir represents the gl_ClipDistance[i] part of the gl_ClipDistance[i][j] input, then: > > > + if (this->old_clip_distance_1d_var) { > This branch will be taken > > + ir_dereference_variable *var_ref = ir->as_dereference_variable(); > But var_ref will be NULL because ir is not a variable dereference, so the following if test will skip: > > + if (var_ref && var_ref->var == this->old_clip_distance_1d_var) > > + return true; > > + } > Then we'll fall through to here > > + if (this->old_clip_distance_2d_var) { > And this branch will be taken. > > + ir_dereference_array *array_ref = ir->as_dereference_array(); > Now array_ref will be non-NULL because the ir is an array dereference. > > + if (array_ref) { > > + ir_dereference_variable *var_ref = > > + array_ref->array->as_dereference_variable(); > So then we'll get here and var_ref will be a reference to the gl_ClipDistance (2D) input variable. > > + if (var_ref && var_ref->var == this->old_clip_distance_2d_var) > > + return true; > > + } > > + } > > + return false; > > +} > Hopefully that helped? > > > + > > + > > +/** > > + * If the given ir satisfies is_clip_distance_vec8(), return new ir > > + * representing its lowered equivalent. That is, map: > > + * > > + * - gl_ClipDistance => gl_ClipDistanceMESA (if gl_ClipDistance > is 1D) > > + * - gl_ClipDistance[i] => gl_ClipDistanceMESA[i] (if gl_ClipDistance > is 2D) > > + * > > + * Otherwise return NULL. > > + */ > > +ir_rvalue * > > +lower_clip_distance_visitor::lower_clip_distance_vec8(ir_rvalue *ir) > > +{ > > + if (this->old_clip_distance_1d_var) { > > + ir_dereference_variable *var_ref = ir->as_dereference_variable(); > > + if (var_ref && var_ref->var == this->old_clip_distance_1d_var) { > > + return new(ralloc_parent(ir)) > > + ir_dereference_variable(this->new_clip_distance_1d_var); > > + } > > + } > > + if (this->old_clip_distance_2d_var) { > > + ir_dereference_array *array_ref = ir->as_dereference_array(); > > + if (array_ref) { > > + ir_dereference_variable *var_ref = > > + array_ref->array->as_dereference_variable(); > > + if (var_ref && var_ref->var == this->old_clip_distance_2d_var) > { > > + return new(ralloc_parent(ir)) > > + ir_dereference_array(this->new_clip_distance_2d_var, > > + array_ref->array_index); > > + } > > + } > > + } > > + return NULL; > > +} > > + > > + > > void > > lower_clip_distance_visitor::handle_rvalue(ir_rvalue **rv) > > { > > - /* If the gl_ClipDistance var hasn't been declared yet, then > > - * there's no way this deref can refer to it. > > - */ > > - if (!this->old_clip_distance_var || *rv == NULL) > > + if (*rv == NULL) > > return; > > > > ir_dereference_array *const array_deref = > (*rv)->as_dereference_array(); > > if (array_deref == NULL) > > return; > > > > - /* Replace any expression that indexes into the gl_ClipDistance array > > + /* Replace any expression that indexes one of the floats in > gl_ClipDistance > > * with an expression that indexes into one of the vec4's in > > * gl_ClipDistanceMESA and accesses the appropriate component. > > */ > > - ir_dereference_variable *old_var_ref = > > - array_deref->array->as_dereference_variable(); > > - if (old_var_ref && old_var_ref->var == this->old_clip_distance_var) { > > + ir_rvalue *lowered_vec8 = > > + this->lower_clip_distance_vec8(array_deref->array); > > + if (lowered_vec8 != NULL) { > > this->progress = true; > > ir_rvalue *array_index; > > ir_rvalue *swizzle_index; > > this->create_indices(array_deref->array_index, array_index, > swizzle_index); > > void *mem_ctx = ralloc_parent(array_deref); > > > > - ir_dereference_array *const ClipDistanceMESA_deref = > > - new(mem_ctx) ir_dereference_array(this->new_clip_distance_var, > > - array_index); > > + ir_dereference_array *const new_array_deref = > > + new(mem_ctx) ir_dereference_array(lowered_vec8, array_index); > > > > ir_expression *const expr = > > new(mem_ctx) ir_expression(ir_binop_vector_extract, > > - ClipDistanceMESA_deref, > > + new_array_deref, > > swizzle_index); > > > > *rv = expr; > > @@ -243,30 +338,34 @@ lower_clip_distance_visitor::fix_lhs(ir_assignment > *ir) > > } > > > > /** > > - * Replace any assignment having gl_ClipDistance (undereferenced) as > its LHS > > - * or RHS with a sequence of assignments, one for each component of the > array. > > - * Each of these assignments is lowered to refer to gl_ClipDistanceMESA > as > > - * appropriate. > > + * Replace any assignment having the 1D gl_ClipDistance > (undereferenced) as > > + * its LHS or RHS with a sequence of assignments, one for each > component of > > + * the array. Each of these assignments is lowered to refer to > > + * gl_ClipDistanceMESA as appropriate. > > + * > > + * We need to do a similar replacement for 2D gl_ClipDistance, however > since > > + * it's an input, the only case we need to address is where a 1D slice > of it > > + * is the entire RHS of an assignment, e.g.: > > + * > > + * foo = gl_in[i].gl_ClipDistance > > */ > > ir_visitor_status > > lower_clip_distance_visitor::visit_leave(ir_assignment *ir) > > { > > - ir_dereference_variable *lhs_var = > ir->lhs->as_dereference_variable(); > > - ir_dereference_variable *rhs_var = > ir->rhs->as_dereference_variable(); > > - if ((lhs_var && lhs_var->var == this->old_clip_distance_var) > > - || (rhs_var && rhs_var->var == this->old_clip_distance_var)) { > > - /* LHS or RHS of the assignment is the entire gl_ClipDistance > array. > > - * Since we are reshaping gl_ClipDistance from an array of floats > to an > > - * array of vec4's, this isn't going to work as a bulk assignment > > - * anymore, so unroll it to element-by-element assignments and > lower > > - * each of them. > > + if (this->is_clip_distance_vec8(ir->lhs) || > > + this->is_clip_distance_vec8(ir->rhs)) { > > + /* LHS or RHS of the assignment is the entire 1D gl_ClipDistance > array > > + * (or a 1D slice of a 2D gl_ClipDistance input array). Since we > are > > + * reshaping gl_ClipDistance from an array of floats to an array > of > > + * vec4's, this isn't going to work as a bulk assignment anymore, > so > > + * unroll it to element-by-element assignments and lower each of > them. > > * > > * Note: to unroll into element-by-element assignments, we need > to make > > * clones of the LHS and RHS. This is safe because expressions > and > > * l-values are side-effect free. > > */ > > void *ctx = ralloc_parent(ir); > > - int array_size = this->old_clip_distance_var->type->array_size(); > > + int array_size = ir->lhs->type->array_size(); > > for (int i = 0; i < array_size; ++i) { > > ir_dereference_array *new_lhs = new(ctx) ir_dereference_array( > > ir->lhs->clone(ctx, NULL), new(ctx) ir_constant(i)); > > @@ -326,11 +425,17 @@ > lower_clip_distance_visitor::visit_new_assignment(ir_assignment *ir) > > > > > > /** > > - * If gl_ClipDistance appears as an argument in an ir_call expression, > replace > > - * it with a temporary variable, and make sure the ir_call is preceded > and/or > > - * followed by assignments that copy the contents of the temporary > variable to > > - * and/or from gl_ClipDistance. Each of these assignments is then > lowered to > > - * refer to gl_ClipDistanceMESA. > > + * If a 1D gl_ClipDistance variable appears as an argument in an ir_call > > + * expression, replace it with a temporary variable, and make sure the > ir_call > > + * is preceded and/or followed by assignments that copy the contents of > the > > + * temporary variable to and/or from gl_ClipDistance. Each of these > > + * assignments is then lowered to refer to gl_ClipDistanceMESA. > > + * > > + * We need to do a similar replacement for 2D gl_ClipDistance, however > since > > + * it's an input, the only case we need to address is where a 1D slice > of it > > + * is passed as an "in" parameter to an ir_call, e.g.: > > + * > > + * foo(gl_in[i].gl_ClipDistance) > > */ > > ir_visitor_status > > lower_clip_distance_visitor::visit_leave(ir_call *ir) > > @@ -349,12 +454,12 @@ lower_clip_distance_visitor::visit_leave(ir_call > *ir) > > formal_param_node = formal_param_node->next; > > actual_param_node = actual_param_node->next; > > > > - ir_dereference_variable *deref = > actual_param->as_dereference_variable(); > > - if (deref && deref->var == this->old_clip_distance_var) { > > - /* User is trying to pass the whole gl_ClipDistance array to a > > - * function call. Since we are reshaping gl_ClipDistance from > an > > - * array of floats to an array of vec4's, this isn't going to > work > > - * anymore, so use a temporary array instead. > > + if (this->is_clip_distance_vec8(actual_param)) { > > + /* User is trying to pass the whole 1D gl_ClipDistance array > (or a 1D > > + * slice of a 2D gl_ClipDistance array) to a function call. > Since we > > + * are reshaping gl_ClipDistance from an array of floats to an > array > > + * of vec4's, this isn't going to work anymore, so use a > temporary > > + * array instead. > > */ > > ir_variable *temp_clip_distance = new(ctx) ir_variable( > > actual_param->type, "temp_clip_distance", ir_var_temporary); > > @@ -370,7 +475,7 @@ lower_clip_distance_visitor::visit_leave(ir_call *ir) > > */ > > ir_assignment *new_assignment = new(ctx) ir_assignment( > > new(ctx) ir_dereference_variable(temp_clip_distance), > > - new(ctx) ir_dereference_variable(old_clip_distance_var)); > > + actual_param->clone(ctx, NULL)); > > this->base_ir->insert_before(new_assignment); > > this->visit_new_assignment(new_assignment); > > } > > @@ -382,7 +487,7 @@ lower_clip_distance_visitor::visit_leave(ir_call *ir) > > * afterwards to make sure it gets lowered. > > */ > > ir_assignment *new_assignment = new(ctx) ir_assignment( > > - new(ctx) ir_dereference_variable(old_clip_distance_var), > > + actual_param->clone(ctx, NULL), > > new(ctx) ir_dereference_variable(temp_clip_distance)); > > this->base_ir->insert_after(new_assignment); > > this->visit_new_assignment(new_assignment); > > @@ -401,8 +506,10 @@ lower_clip_distance(gl_shader *shader) > > > > visit_list_elements(&v, shader->ir); > > > > - if (v.new_clip_distance_var) > > - shader->symbols->add_variable(v.new_clip_distance_var); > > + if (v.new_clip_distance_1d_var) > > + shader->symbols->add_variable(v.new_clip_distance_1d_var); > > + if (v.new_clip_distance_2d_var) > > + shader->symbols->add_variable(v.new_clip_distance_2d_var); > > > > return v.progress; > > } > > > >
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