svga: add new svga_link.[ch] files

Signed-off-by: Brian Paul <brianp@vmware.com>

src/gallium/drivers/svga/svga_link.c

@@ -0,0 +1,120 @@
+/*/
+ * Copyright 2013 VMware, Inc.  All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+
+#include "svga_context.h"
+#include "svga_link.h"
+
+#include "tgsi/tgsi_strings.h"
+
+
+#define INVALID_INDEX 255
+
+
+/**
+ * Examine input and output shaders info to link outputs from the
+ * output shader to inputs from the input shader.
+ * Basically, we'll remap input shader's input slots to new numbers
+ * based on semantic name/index of the outputs from the output shader.
+ */
+void
+svga_link_shaders(const struct tgsi_shader_info *outshader_info,
+                  const struct tgsi_shader_info *inshader_info,
+                  struct shader_linkage *linkage)
+{
+   unsigned i, free_slot;
+
+   for (i = 0; i < Elements(linkage->input_map); i++) {
+      linkage->input_map[i] = INVALID_INDEX;
+   }
+
+   /* Assign input slots for input shader inputs.
+    * Basically, we want to use the same index for the output shader's outputs
+    * and the input shader's inputs that should be linked together.
+    * We'll modify the input shader's inputs to match the output shader.
+    */
+   assert(inshader_info->num_inputs <=
+          Elements(inshader_info->input_semantic_name));
+
+   /* free register index that can be used for built-in varyings */
+   free_slot = outshader_info->num_outputs + 1;
+
+   for (i = 0; i < inshader_info->num_inputs; i++) {
+      unsigned sem_name = inshader_info->input_semantic_name[i];
+      unsigned sem_index = inshader_info->input_semantic_index[i];
+      unsigned j;
+      /**
+       * Get the clip distance inputs from the output shader's
+       * clip distance shadow copy.
+       */
+      if (sem_name == TGSI_SEMANTIC_CLIPDIST) {
+         linkage->input_map[i] = outshader_info->num_outputs + 1 + sem_index;
+         /* make sure free_slot includes this extra output */
+         free_slot = MAX2(free_slot, linkage->input_map[i] + 1);
+      }
+      else {
+         /* search output shader outputs for same item */
+         for (j = 0; j < outshader_info->num_outputs; j++) {
+            assert(j < Elements(outshader_info->output_semantic_name));
+            if (outshader_info->output_semantic_name[j] == sem_name &&
+                outshader_info->output_semantic_index[j] == sem_index) {
+               linkage->input_map[i] = j;
+               break;
+            }
+         }
+      }
+   }
+
+   linkage->num_inputs = inshader_info->num_inputs;
+
+   /* Things like the front-face register are handled here */
+   for (i = 0; i < inshader_info->num_inputs; i++) {
+      if (linkage->input_map[i] == INVALID_INDEX) {
+         unsigned j = free_slot++;
+         linkage->input_map[i] = j;
+      }
+   }
+
+   /* Debug */
+   if (0) {
+      unsigned reg = 0;
+      for (i = 0; i < linkage->num_inputs; i++) {
+
+         assert(linkage->input_map[i] != INVALID_INDEX);
+
+         debug_printf("input shader input[%d] slot %u  %s %u %s\n",
+                      i,
+                      linkage->input_map[i],
+                      tgsi_semantic_names[inshader_info->input_semantic_name[i]],
+                      inshader_info->input_semantic_index[i],
+                      tgsi_interpolate_names[inshader_info->input_interpolate[i]]);
+
+         /* make sure no repeating register index */
+         if (reg & 1 << linkage->input_map[i]) {
+            assert(0);
+         }
+         reg |= 1 << linkage->input_map[i];
+      }
+   }
+}

src/gallium/drivers/svga/svga_link.h

@@ -0,0 +1,20 @@
+
+#ifndef SVGA_LINK_H
+#define SVGA_LINK_H
+
+#include "pipe/p_defines.h"
+
+struct svga_context;
+
+struct shader_linkage
+{
+   unsigned num_inputs;
+   ubyte input_map[PIPE_MAX_SHADER_INPUTS];
+};
+
+void
+svga_link_shaders(const struct tgsi_shader_info *outshader_info,
+                  const struct tgsi_shader_info *inshader_info,
+                  struct shader_linkage *linkage);
+
+#endif /* SVGA_LINK_H */