[Mesa-dev] [PATCH 15/21] linker: Modify cross_validate_outputs_to_inputs to match using explicit locations

Ian Romanick idr at freedesktop.org
Tue Apr 29 17:52:18 PDT 2014


From: Ian Romanick <ian.d.romanick at intel.com>

This will be used for GL_ARB_separate_shader_objects.  That extension
not only allows separable shaders to rendezvous by location, but it also
allows traditionally linked shaders to rendezvous by location.  The spec
says:

    36. How does the behavior of input/output interface matching differ
        between separable programs and non-separable programs?

        RESOLVED: The rules for matching individual variables or block
        members between stages are identical for separable and
        non-separable programs, with one exception -- matching variables
        of different type with the same location, as discussed in issue
        34, applies only to separable programs.

        However, the ability to enforce matching requirements differs
        between program types.  In non-separable programs, both sides of
        an interface are contained in the same linked program.  In this
        case, if the linker detects a mismatch, it will generate a link
        error.

v2: Make sure consumer_inputs_with_locations is initialized when
consumer is NULL.  Noticed by Chia-I.

v3: Rebase on removal of ir_variable::user_location.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
---
 src/glsl/link_varyings.cpp       | 75 +++++++++++++++++++++++++++++++++++-----
 src/glsl/tests/varyings_test.cpp | 35 ++++++++++++-------
 2 files changed, 90 insertions(+), 20 deletions(-)

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index e5c2751..232e230 100644
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -172,6 +172,7 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
 				 gl_shader *producer, gl_shader *consumer)
 {
    glsl_symbol_table parameters;
+   ir_variable *explicit_locations[MAX_VARYING] = { NULL, };
 
    /* Find all shader outputs in the "producer" stage.
     */
@@ -181,7 +182,26 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
       if ((var == NULL) || (var->data.mode != ir_var_shader_out))
 	 continue;
 
-      parameters.add_variable(var);
+      if (!var->data.explicit_location
+          || var->data.location < VARYING_SLOT_VAR0)
+         parameters.add_variable(var);
+      else {
+         /* User-defined varyings with explicit locations are handled
+          * differently because they do not need to have matching names.
+          */
+         const unsigned idx = var->data.location - VARYING_SLOT_VAR0;
+
+         if (explicit_locations[idx] != NULL) {
+            linker_error(prog,
+                         "%s shader has multiple outputs explicitly "
+                         "assigned to location %d\n",
+                         _mesa_shader_stage_to_string(producer->Stage),
+                         idx);
+            return;
+         }
+
+         explicit_locations[idx] = var;
+      }
    }
 
 
@@ -220,7 +240,27 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
                                              front_color, back_color,
                                              consumer->Stage, producer->Stage);
       } else {
-         ir_variable *const output = parameters.get_variable(input->name);
+         /* The rules for connecting inputs and outputs change in the presence
+          * of explicit locations.  In this case, we no longer care about the
+          * names of the variables.  Instead, we care only about the
+          * explicitly assigned location.
+          */
+         ir_variable *output = NULL;
+         if (input->data.explicit_location
+             && input->data.location >= VARYING_SLOT_VAR0) {
+            output = explicit_locations[input->data.location - VARYING_SLOT_VAR0];
+
+            if (output == NULL) {
+               linker_error(prog,
+                            "%s shader input `%s' with explicit location "
+                            "has no matching output\n",
+                            _mesa_shader_stage_to_string(consumer->Stage),
+                            input->name);
+            }
+         } else {
+            output = parameters.get_variable(input->name);
+         }
+
          if (output != NULL) {
             cross_validate_types_and_qualifiers(prog, input, output,
                                                 consumer->Stage, producer->Stage);
@@ -1051,8 +1091,13 @@ namespace linker {
 bool
 populate_consumer_input_sets(void *mem_ctx, exec_list *ir,
                              hash_table *consumer_inputs,
-                             hash_table *consumer_interface_inputs)
+                             hash_table *consumer_interface_inputs,
+                             ir_variable *consumer_inputs_with_locations[MAX_VARYING])
 {
+   memset(consumer_inputs_with_locations,
+          0,
+          sizeof(consumer_inputs_with_locations[0]) * MAX_VARYING);
+
    foreach_list(node, ir) {
       ir_variable *const input_var = ((ir_instruction *) node)->as_variable();
 
@@ -1060,7 +1105,13 @@ populate_consumer_input_sets(void *mem_ctx, exec_list *ir,
          if (input_var->type->is_interface())
             return false;
 
-         if (input_var->get_interface_type() != NULL) {
+         if (input_var->data.explicit_location) {
+            /* FINISHME: If the input is an interface, array, or structure, it
+             * FINISHME: will use multiple slots.
+             */
+            consumer_inputs_with_locations[input_var->data.location] =
+               input_var;
+         } else if (input_var->get_interface_type() != NULL) {
             char *const iface_field_name =
                ralloc_asprintf(mem_ctx, "%s.%s",
                                input_var->get_interface_type()->name,
@@ -1087,11 +1138,14 @@ ir_variable *
 get_matching_input(void *mem_ctx,
                    const ir_variable *output_var,
                    hash_table *consumer_inputs,
-                   hash_table *consumer_interface_inputs)
+                   hash_table *consumer_interface_inputs,
+                   ir_variable *consumer_inputs_with_locations[MAX_VARYING])
 {
    ir_variable *input_var;
 
-   if (output_var->get_interface_type() != NULL) {
+   if (output_var->data.explicit_location) {
+      input_var = consumer_inputs_with_locations[output_var->data.location];
+   } else if (output_var->get_interface_type() != NULL) {
       char *const iface_field_name =
          ralloc_asprintf(mem_ctx, "%s.%s",
                          output_var->get_interface_type()->name,
@@ -1210,6 +1264,9 @@ assign_varying_locations(struct gl_context *ctx,
       = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
    hash_table *consumer_interface_inputs
       = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
+   ir_variable *consumer_inputs_with_locations[MAX_VARYING] = {
+      NULL,
+   };
 
    /* Operate in a total of four passes.
     *
@@ -1236,7 +1293,8 @@ assign_varying_locations(struct gl_context *ctx,
        && !linker::populate_consumer_input_sets(mem_ctx,
                                                 consumer->ir,
                                                 consumer_inputs,
-                                                consumer_interface_inputs)) {
+                                                consumer_interface_inputs,
+                                                consumer_inputs_with_locations)) {
       assert(!"populate_consumer_input_sets failed");
       hash_table_dtor(tfeedback_candidates);
       hash_table_dtor(consumer_inputs);
@@ -1258,7 +1316,8 @@ assign_varying_locations(struct gl_context *ctx,
 
          ir_variable *const input_var =
             linker::get_matching_input(mem_ctx, output_var, consumer_inputs,
-                                       consumer_interface_inputs);
+                                       consumer_interface_inputs,
+                                       consumer_inputs_with_locations);
 
          /* If a matching input variable was found, add this ouptut (and the
           * input) to the set.  If this is a separable program and there is no
diff --git a/src/glsl/tests/varyings_test.cpp b/src/glsl/tests/varyings_test.cpp
index 1749112..8a188a7 100644
--- a/src/glsl/tests/varyings_test.cpp
+++ b/src/glsl/tests/varyings_test.cpp
@@ -38,13 +38,15 @@ namespace linker {
 bool
 populate_consumer_input_sets(void *mem_ctx, exec_list *ir,
                              hash_table *consumer_inputs,
-                             hash_table *consumer_interface_inputs);
+                             hash_table *consumer_interface_inputs,
+                             ir_variable *consumer_inputs_with_locations[MAX_VARYING]);
 
 ir_variable *
 get_matching_input(void *mem_ctx,
                    const ir_variable *output_var,
                    hash_table *consumer_inputs,
-                   hash_table *consumer_interface_inputs);
+                   hash_table *consumer_interface_inputs,
+                   ir_variable *consumer_inputs_with_locations[MAX_VARYING]);
 }
 
 class link_varyings : public ::testing::Test {
@@ -68,6 +70,7 @@ public:
    hash_table *consumer_interface_inputs;
 
    const glsl_type *simple_interface;
+   ir_variable *junk[MAX_VARYING];
 };
 
 link_varyings::link_varyings()
@@ -164,7 +167,8 @@ TEST_F(link_varyings, single_simple_input)
    ASSERT_TRUE(linker::populate_consumer_input_sets(mem_ctx,
                                                     &ir,
                                                     consumer_inputs,
-                                                    consumer_interface_inputs));
+                                                    consumer_interface_inputs,
+                                                    junk));
 
    EXPECT_EQ((void *) v, hash_table_find(consumer_inputs, "a"));
    EXPECT_EQ(1u, num_elements(consumer_inputs));
@@ -190,7 +194,8 @@ TEST_F(link_varyings, gl_ClipDistance)
    ASSERT_TRUE(linker::populate_consumer_input_sets(mem_ctx,
                                                     &ir,
                                                     consumer_inputs,
-                                                    consumer_interface_inputs));
+                                                    consumer_interface_inputs,
+                                                    junk));
 
    EXPECT_EQ((void *) clipdistance,
              hash_table_find(consumer_inputs, "gl_ClipDistance"));
@@ -212,8 +217,8 @@ TEST_F(link_varyings, single_interface_input)
    ASSERT_TRUE(linker::populate_consumer_input_sets(mem_ctx,
                                                     &ir,
                                                     consumer_inputs,
-                                                    consumer_interface_inputs));
-
+                                                    consumer_interface_inputs,
+                                                    junk));
    char *const full_name = interface_field_name(simple_interface);
 
    EXPECT_EQ((void *) v, hash_table_find(consumer_interface_inputs, full_name));
@@ -243,7 +248,8 @@ TEST_F(link_varyings, one_interface_and_one_simple_input)
    ASSERT_TRUE(linker::populate_consumer_input_sets(mem_ctx,
                                                     &ir,
                                                     consumer_inputs,
-                                                    consumer_interface_inputs));
+                                                    consumer_interface_inputs,
+                                                    junk));
 
    char *const iface_field_name = interface_field_name(simple_interface);
 
@@ -269,7 +275,8 @@ TEST_F(link_varyings, invalid_interface_input)
    EXPECT_FALSE(linker::populate_consumer_input_sets(mem_ctx,
                                                     &ir,
                                                     consumer_inputs,
-                                                    consumer_interface_inputs));
+                                                     consumer_interface_inputs,
+                                                     junk));
 }
 
 TEST_F(link_varyings, interface_field_doesnt_match_noninterface)
@@ -288,7 +295,8 @@ TEST_F(link_varyings, interface_field_doesnt_match_noninterface)
    ASSERT_TRUE(linker::populate_consumer_input_sets(mem_ctx,
                                                     &ir,
                                                     consumer_inputs,
-                                                    consumer_interface_inputs));
+                                                    consumer_interface_inputs,
+                                                    junk));
 
    /* Create an output variable, "v", that is part of an interface block named
     * "a".  They should not match.
@@ -304,7 +312,8 @@ TEST_F(link_varyings, interface_field_doesnt_match_noninterface)
       linker::get_matching_input(mem_ctx,
                                  out_v,
                                  consumer_inputs,
-                                 consumer_interface_inputs);
+                                 consumer_interface_inputs,
+                                 junk);
 
    EXPECT_EQ(NULL, match);
 }
@@ -328,7 +337,8 @@ TEST_F(link_varyings, interface_field_doesnt_match_noninterface_vice_versa)
    ASSERT_TRUE(linker::populate_consumer_input_sets(mem_ctx,
                                                     &ir,
                                                     consumer_inputs,
-                                                    consumer_interface_inputs));
+                                                    consumer_interface_inputs,
+                                                    junk));
 
    /* Create an output variable "a.v".  They should not match.
     */
@@ -341,7 +351,8 @@ TEST_F(link_varyings, interface_field_doesnt_match_noninterface_vice_versa)
       linker::get_matching_input(mem_ctx,
                                  out_v,
                                  consumer_inputs,
-                                 consumer_interface_inputs);
+                                 consumer_interface_inputs,
+                                 junk);
 
    EXPECT_EQ(NULL, match);
 }
-- 
1.8.1.4



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