[Mesa-dev] [PATCH v4 06/15] mesa/st/glsl_to_tgsi: Add helper classes to apply array merging and interleaving

[Gert Wollny]

  v4: - Remove logic for evaluation of swizzles and merges since this
        was moved to array_live_range. This class now only handles the
        actual remapping.

Signed-off-by: Gert Wollny <gw.fossdev at gmail.com>
---
 .../state_tracker/st_glsl_to_tgsi_array_merge.cpp  | 100 +++++++++++++++++++++
 .../state_tracker/st_glsl_to_tgsi_array_merge.h    |  65 +++++++++++++-
 2 files changed, 164 insertions(+), 1 deletion(-)

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.cpp
index d84a71ba39..a6c54c43df 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.cpp
@@ -215,3 +215,103 @@ bool array_live_range::time_doesnt_overlap(const array_live_range& other) const
    return (other.last_access < first_access ||
            last_access < other.first_access);
 }
+
+namespace tgsi_array_merge {
+
+array_remapping::array_remapping():
+   target_id(0)
+{
+   for (int i = 0; i < 4; ++i) {
+      read_swizzle_map[i] = i;
+   }
+}
+
+array_remapping::array_remapping(int trgt_array_id, const int8_t swizzle[]):
+   target_id(trgt_array_id)
+{
+   for (int i = 0; i < 4; ++i) {
+      read_swizzle_map[i] = swizzle[i];
+   }
+}
+
+void array_remapping::init_from(const array_live_range& range)
+{
+   target_id = range.is_mapped() ? range.final_target()->array_id(): 0;
+   for (int i = 0; i < 4; ++i)
+      read_swizzle_map[i] = range.remap_one_swizzle(i);
+}
+
+
+int array_remapping::map_writemask(int write_mask) const
+{
+   assert(is_valid());
+   int result_write_mask = 0;
+   for (int i = 0; i < 4; ++i) {
+      if (1 << i & write_mask) {
+         assert(read_swizzle_map[i] >= 0);
+         result_write_mask |= 1 << read_swizzle_map[i];
+      }
+   }
+   return result_write_mask;
+}
+
+uint16_t array_remapping::move_read_swizzles(uint16_t original_swizzle) const
+{
+   assert(is_valid());
+   /* Since
+    *
+    *   dst.zw = src.xy in glsl actually is MOV dst.__zw src.__xy
+    *
+    * when interleaving the arrays the source swizzles must be moved
+    * according to the changed dst write mask.
+    */
+   uint16_t out_swizzle = 0;
+   for (int idx = 0; idx < 4; ++idx) {
+      uint16_t orig_swz = GET_SWZ(original_swizzle, idx);
+      int new_idx = read_swizzle_map[idx];
+      if (new_idx >= 0)
+         out_swizzle |= orig_swz << 3 * new_idx;
+   }
+   return out_swizzle;
+}
+
+uint16_t array_remapping::map_swizzles(uint16_t old_swizzle) const
+{
+   uint16_t out_swizzle = 0;
+   for (int idx = 0; idx < 4; ++idx) {
+      uint16_t swz = read_swizzle_map[GET_SWZ(old_swizzle, idx)];
+      out_swizzle |= swz << 3 * idx;
+   }
+   return out_swizzle;
+}
+
+void array_remapping::print(std::ostream& os) const
+{
+   if (is_valid()) {
+      os << "[aid: " << target_id << " swz: ";
+      for (int i = 0; i < 4; ++i)
+         os << (read_swizzle_map[i] >= 0 ? xyzw[read_swizzle_map[i]] : '_');
+      os << "]";
+   } else {
+      os << "[unused]";
+   }
+}
+
+/* Required by the unit tests */
+bool operator == (const array_remapping& lhs, const array_remapping& rhs)
+{
+   if (lhs.target_id != rhs.target_id)
+      return false;
+
+   if (lhs.target_id == 0)
+      return true;
+
+   for (int i = 0; i < 4; ++i) {
+      if (lhs.read_swizzle_map[i] != rhs.read_swizzle_map[i])
+         return false;
+   }
+   return true;
+}
+
+/* end namespace tgsi_array_merge */
+}
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.h b/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.h
index 2234d2a97a..9915bc2e4b 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.h
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi_array_merge.h
@@ -95,4 +95,67 @@ std::ostream& operator << (std::ostream& os, const array_live_range& lt) {
    lt.print(os);
    return os;
 }
-#endif
\ No newline at end of file
+
+namespace tgsi_array_merge {
+
+/* Helper class to apply array merge and interleav to the shader.
+ * The interface is exposed here to make unit tests possible.
+ */
+class array_remapping {
+public:
+
+   /** Create an invalid mapping that is used as place-holder for
+    * arrays that are not mapped at all.
+    */
+   array_remapping();
+
+   /* Predefined remapping, needed for testing */
+   array_remapping(int trgt_array_id, const int8_t swizzle[]);
+
+   /* Initialiaze the mapping from an array_live_range that has been
+    * processed by the array merge and interleave algorithm.
+    */
+   void init_from(const array_live_range& range);
+
+   /* (Re)-set target id, needed when the mapping is resolved */
+   void set_target_id(int tid) {target_id = tid;}
+
+   /* Defines a valid remapping */
+   bool is_valid() const {return target_id > 0;}
+
+   /* Translates the write mask to the new, interleaved component
+    * position
+    */
+   int map_writemask(int original_write_mask) const;
+
+   /* Translates all read swizzles to the new, interleaved component
+    * swizzles
+    */
+   uint16_t map_swizzles(uint16_t original_swizzle) const;
+
+   /* Move the read swizzles to the positiones that correspond to
+    * a changed write mask.
+    */
+   uint16_t move_read_swizzles(uint16_t original_swizzle) const;
+
+   unsigned target_array_id() const {return target_id;}
+
+   void print(std::ostream& os) const;
+
+   friend bool operator == (const array_remapping& lhs,
+                            const array_remapping& rhs);
+
+private:
+   unsigned target_id;
+   int8_t read_swizzle_map[4];
+};
+
+inline
+std::ostream& operator << (std::ostream& os, const array_remapping& am)
+{
+   am.print(os);
+   return os;
+}
+
+}
+#endif
-- 
2.16.4