glsl: Basic support for built-in intrinsics.

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.

Reviewed-by: Ian Romanick <[email protected]>

v2: Define local helper function to generate ir_call nodes in the
    builtin generator.

1 files changed, 10 insertions, 6 deletions

diff --git a/src/glsl/link_functions.cpp b/src/glsl/link_functions.cpp
index fd800999802..68aa6203289 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
@@ -307,7 +310,8 @@ 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