glsl: make max array trackers ints and use -1 as base. (v2)

This fixes a bug that breaks cull distances. The problem
is the max array accessors can't tell the difference between
an never accessed unsized array and an accessed at location 0
unsized array. This leads to converting an undeclared unused
gl_ClipDistance inside or outside gl_PerVertex to a size 1
array. However we need to the number of active clip distances
to work out the starting point for the cull distances, and
this offset by one when it's not being used isn't possible
to distinguish from the case were only the first element is
accessed. I tried to use ->used for this, but that doesn't
work when gl_ClipDistance is part of an interface block.

So this changes things so that max_array_access is an int
and initialised to -1. This also allows unsized arrays to
proceed further than that could before, but we really shouldn't
mind as they will get eliminated if nothing uses them later.

For initialised uniforms we no longer change their array
size at runtime, if these are unused they will get eliminated
eventually.

v2: use ralloc_array (Ilia)

Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/src/compiler/glsl/ir.h b/src/compiler/glsl/ir.h
index 6e0dc0b..d52dbf8 100644
--- a/src/compiler/glsl/ir.h
+++ b/src/compiler/glsl/ir.h
@@ -484,7 +484,10 @@ public:
       this->interface_type = type;
       if (this->is_interface_instance()) {
          this->u.max_ifc_array_access =
-            rzalloc_array(this, unsigned, type->length);
+            ralloc_array(this, int, type->length);
+         for (unsigned i = 0; i < type->length; i++) {
+            this->u.max_ifc_array_access[i] = -1;
+         }
       }
    }
 
@@ -520,7 +523,7 @@ public:
           * zero.
           */
          for (unsigned i = 0; i < this->interface_type->length; i++)
-            assert(this->u.max_ifc_array_access[i] == 0);
+            assert(this->u.max_ifc_array_access[i] == -1);
 #endif
          ralloc_free(this->u.max_ifc_array_access);
          this->u.max_ifc_array_access = NULL;
@@ -540,7 +543,7 @@ public:
     * A "set" function is not needed because the array is dynmically allocated
     * as necessary.
     */
-   inline unsigned *get_max_ifc_array_access()
+   inline int *get_max_ifc_array_access()
    {
       assert(this->data._num_state_slots == 0);
       return this->u.max_ifc_array_access;
@@ -888,9 +891,9 @@ public:
       /**
        * Highest element accessed with a constant expression array index
        *
-       * Not used for non-array variables.
+       * Not used for non-array variables. -1 is never accessed.
        */
-      unsigned max_array_access;
+      int max_array_access;
 
       /**
        * Transform feedback buffer.
@@ -938,7 +941,7 @@ private:
        * For variables whose type is not an interface block, this pointer is
        * NULL.
        */
-      unsigned *max_ifc_array_access;
+      int *max_ifc_array_access;
 
       /**
        * Built-in state that backs this uniform