Mesa (master): nir: Add a little more docs about NIR's constant_data.

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Module: Mesa
Branch: master
Commit: 041bae28c674cee32dd24be817598a73c0dba950
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=041bae28c674cee32dd24be817598a73c0dba950

Author: Eric Anholt <eric at anholt.net>
Date:   Tue Jul  7 12:25:13 2020 -0700

nir: Add a little more docs about NIR's constant_data.

I think everyone trips over "how does this relate to nir_const", and I was
curious if I could redefine the units of the constant_data_size / indirect
offsets.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Reviewed-by: Rob Clark <robdclark at chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6179>

---

 src/compiler/nir/nir.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index edae673bfa6..0f3578e7f8a 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -3246,10 +3246,14 @@ typedef struct nir_shader {
 
    /** Constant data associated with this shader.
     *
-    * Constant data is loaded through load_constant intrinsics.  See also
-    * nir_opt_large_constants.
+    * Constant data is loaded through load_constant intrinsics (as compared to
+    * the NIR load_const instructions which have the constant value inlined
+    * into them).  This is usually generated by nir_opt_large_constants (so
+    * shaders don't have to load_const into a temporary array when they want
+    * to indirect on a const array).
     */
    void *constant_data;
+   /** Size of the constant data associated with the shader, in bytes */
    unsigned constant_data_size;
 } nir_shader;