[Mesa-dev] [PATCH 04/14] glsl: Basic support for built-in intrinsics.

[Francisco Jerez]

Fix the linker to deal with intrinsic functions which are undefined
all the way down to the driver back-end, and introduce intrinsic
definition helpers in the built-in generator.

We still need to figure out what kind of interface we want for drivers
to communicate to the GLSL front-end which of the supported intrinsics
should use a default GLSL implementation and which should use a
hardware-specific override.  As there's no default GLSL implementation
for atomic ops, this seems like something we can worry about later on.
---
 src/glsl/builtin_functions.cpp | 21 ++++++++++++++++++---
 src/glsl/ir.cpp                |  4 ++--
 src/glsl/ir.h                  |  6 ++++++
 src/glsl/link_functions.cpp    | 16 ++++++++++------
 4 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/src/glsl/builtin_functions.cpp b/src/glsl/builtin_functions.cpp
index 72054e0..03efb6d 100644
--- a/src/glsl/builtin_functions.cpp
+++ b/src/glsl/builtin_functions.cpp
@@ -339,6 +339,7 @@ private:
    ir_variable *gl_Vertex;
 
    void create_shader();
+   void create_intrinsics();
    void create_builtins();
 
    /**
@@ -576,6 +577,7 @@ builtin_builder::initialize()
 
    mem_ctx = ralloc_context(NULL);
    create_shader();
+   create_intrinsics();
    create_builtins();
 }
 
@@ -613,6 +615,15 @@ builtin_builder::create_shader()
 /** @} */
 
 /**
+ * Create ir_function and ir_function_signature objects for each
+ * intrinsic.
+ */
+void
+builtin_builder::create_intrinsics()
+{
+}
+
+/**
  * Create ir_function and ir_function_signature objects for each built-in.
  *
  * Contains a list of every available built-in.
@@ -1865,8 +1876,6 @@ builtin_builder::add_function(const char *name, ...)
       if (sig == NULL)
          break;
 
-      sig->is_defined = true;
-
       if (false) {
          exec_list stuff;
          stuff.push_tail(sig);
@@ -1964,7 +1973,13 @@ builtin_builder::new_sig(const glsl_type *return_type,
 #define MAKE_SIG(return_type, avail, ...)  \
    ir_function_signature *sig =               \
       new_sig(return_type, avail, __VA_ARGS__);      \
-   ir_factory body(&sig->body, mem_ctx);
+   ir_factory body(&sig->body, mem_ctx);             \
+   sig->is_defined = true;
+
+#define MAKE_INTRINSIC(return_type, avail, ...)      \
+   ir_function_signature *sig =                      \
+      new_sig(return_type, avail, __VA_ARGS__);      \
+   sig->is_intrinsic = true;
 
 ir_function_signature *
 builtin_builder::unop(builtin_available_predicate avail,
diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index d65d8dc..02563e7 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -1633,8 +1633,8 @@ ir_variable::determine_interpolation_mode(bool flat_shade)
 
 ir_function_signature::ir_function_signature(const glsl_type *return_type,
                                              builtin_available_predicate b)
-   : return_type(return_type), is_defined(false), builtin_avail(b),
-     _function(NULL)
+   : return_type(return_type), is_defined(false), is_intrinsic(false),
+     builtin_avail(b), _function(NULL)
 {
    this->ir_type = ir_type_function_signature;
    this->origin = NULL;
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index fd12ae6..b87819c 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -694,6 +694,12 @@ public:
    /** Whether or not this function signature is a built-in. */
    bool is_builtin() const;
 
+   /**
+    * Whether or not this function is an intrinsic to be implemented
+    * by the driver.
+    */
+   bool is_intrinsic;
+
    /** Whether or not a built-in is available for this shader. */
    bool is_builtin_available(const _mesa_glsl_parse_state *state) const;
 
diff --git a/src/glsl/link_functions.cpp b/src/glsl/link_functions.cpp
index b1a68fd..c8531ed 100644
--- a/src/glsl/link_functions.cpp
+++ b/src/glsl/link_functions.cpp
@@ -155,14 +155,17 @@ public:
 
       linked_sig->replace_parameters(&formal_parameters);
 
-      foreach_list_const(node, &sig->body) {
-	 const ir_instruction *const original = (ir_instruction *) node;
+      if (sig->is_defined) {
+         foreach_list_const(node, &sig->body) {
+            const ir_instruction *const original = (ir_instruction *) node;
 
-	 ir_instruction *copy = original->clone(linked, ht);
-	 linked_sig->body.push_tail(copy);
+            ir_instruction *copy = original->clone(linked, ht);
+            linked_sig->body.push_tail(copy);
+         }
+
+         linked_sig->is_defined = true;
       }
 
-      linked_sig->is_defined = true;
       hash_table_dtor(ht);
 
       /* Patch references inside the function to things outside the function
@@ -294,7 +297,8 @@ find_matching_signature(const char *name, const exec_list *actual_parameters,
       ir_function_signature *sig =
          f->matching_signature(NULL, actual_parameters);
 
-      if ((sig == NULL) || !sig->is_defined)
+      if ((sig == NULL) ||
+          (!sig->is_defined && !sig->is_intrinsic))
 	 continue;
 
       /* If this function expects to bind to a built-in function and the
-- 
1.8.3.4