mesa: add infrastructure for bindless samplers/images bound to units

Yes, ARB_bindless_texture allows to do this. In other words, in
a situation like:

layout (bindless_sampler) uniform sampler2D tex;

The 'tex' sampler uniform can be either set with glUniform1()
(old-style bound samplers) or with glUniformHandleui() (resident
handles).

When glUniform1() is used, we have to somehow make the texture
resident "under the hood". This is done by requesting a texture
handle to the driver, making the handle resident in the current
context and overwriting the value directly in the constant buffer.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/mesa/main/mtypes.h

@@ -1990,6 +1990,42 @@ struct gl_perf_query_state
 };
 
 
+/**
+ * A bindless sampler object.
+ */
+struct gl_bindless_sampler
+{
+   /** Texture unit (set by glUniform1()). */
+   GLubyte unit;
+
+   /** Texture Target (TEXTURE_1D/2D/3D/etc_INDEX). */
+   gl_texture_index target;
+
+   /** Whether this bindless sampler is bound to a unit. */
+   GLboolean bound;
+
+   /** Pointer to the base of the data. */
+   GLvoid *data;
+};
+
+/**
+ * A bindless image object.
+ */
+struct gl_bindless_image
+{
+   /** Image unit (set by glUniform1()). */
+   GLubyte unit;
+
+   /** Access qualifier (GL_READ_WRITE, GL_READ_ONLY, GL_WRITE_ONLY) */
+   GLenum access;
+
+   /** Whether this bindless image is bound to a unit. */
+   GLboolean bound;
+
+   /** Pointer to the base of the data. */
+   GLvoid *data;
+};
+
 /**
  * Names of the various vertex/fragment program register files, etc.
  *
@@ -2124,6 +2160,22 @@ struct gl_program
           */
          gl_texture_index SamplerTargets[MAX_SAMPLERS];
 
+         /**
+          * Number of samplers declared with the bindless_sampler layout
+          * qualifier as specified by ARB_bindless_texture.
+          */
+         GLuint NumBindlessSamplers;
+         GLboolean HasBoundBindlessSampler;
+         struct gl_bindless_sampler *BindlessSamplers;
+
+         /**
+          * Number of images declared with the bindless_image layout qualifier
+          * as specified by ARB_bindless_texture.
+          */
+         GLuint NumBindlessImages;
+         GLboolean HasBoundBindlessImage;
+         struct gl_bindless_image *BindlessImages;
+
          union {
             struct {
                /**