From 3b4d4c7d8418c40000e25ecbda99f6a10d089b8c Mon Sep 17 00:00:00 2001
From: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Date: Tue, 18 Jan 2022 11:50:37 +0100
Subject: [PATCH] mesa: use less temporaries in build_lighting
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Preallocating temporaries can cause "out of temporaries" error.
Switch to on-demand allocation.

Growing temp_in_use would be an alternative, but some drivers
support less than 64 temps (see PIPE_SHADER_CAP_MAX_TEMPS) so
this wouldn't help them.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/5777
Fixes: 272acbed0e2 ("mesa: merge STATE_LIGHTPROD parameters")
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14590>
---
 src/mesa/main/ffvertex_prog.c | 56 +++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 12 deletions(-)

diff --git a/src/mesa/main/ffvertex_prog.c b/src/mesa/main/ffvertex_prog.c
index 2ea2d11f6f5..24face21db3 100644
--- a/src/mesa/main/ffvertex_prog.c
+++ b/src/mesa/main/ffvertex_prog.c
@@ -919,19 +919,19 @@ static struct ureg get_scenecolor( struct tnl_program *p, GLuint side )
 
 
 static struct ureg get_lightprod( struct tnl_program *p, GLuint light,
-				  GLuint side, GLuint property )
+				  GLuint side, GLuint property, bool *is_state_light )
 {
    GLuint attrib = material_attrib(side, property);
    if (p->materials & (1<<attrib)) {
       struct ureg light_value =
 	 register_param3(p, STATE_LIGHT, light, property);
-      struct ureg material_value = get_material(p, side, property);
-      struct ureg tmp = get_temp(p);
-      emit_op2(p, OPCODE_MUL, tmp, 0, light_value, material_value);
-      return tmp;
+    *is_state_light = true;
+    return light_value;
    }
-   else
+   else {
+      *is_state_light = false;
       return register_param3(p, STATE_LIGHTPROD, light, attrib);
+   }
 }
 
 
@@ -1117,20 +1117,28 @@ static void build_lighting( struct tnl_program *p )
     */
    struct ureg lightprod_front[MAX_LIGHTS][3];
    struct ureg lightprod_back[MAX_LIGHTS][3];
+   bool lightprod_front_is_state_light[MAX_LIGHTS][3];
+   bool lightprod_back_is_state_light[MAX_LIGHTS][3];
 
    for (i = 0; i < MAX_LIGHTS; i++) {
       if (p->state->unit[i].light_enabled) {
-         lightprod_front[i][0] = get_lightprod(p, i, 0, STATE_AMBIENT);
+         lightprod_front[i][0] = get_lightprod(p, i, 0, STATE_AMBIENT,
+                                               &lightprod_front_is_state_light[i][0]);
          if (twoside)
-            lightprod_back[i][0] = get_lightprod(p, i, 1, STATE_AMBIENT);
+            lightprod_back[i][0] = get_lightprod(p, i, 1, STATE_AMBIENT,
+                                                 &lightprod_back_is_state_light[i][0]);
 
-         lightprod_front[i][1] = get_lightprod(p, i, 0, STATE_DIFFUSE);
+         lightprod_front[i][1] = get_lightprod(p, i, 0, STATE_DIFFUSE,
+                                               &lightprod_front_is_state_light[i][1]);
          if (twoside)
-            lightprod_back[i][1] = get_lightprod(p, i, 1, STATE_DIFFUSE);
+            lightprod_back[i][1] = get_lightprod(p, i, 1, STATE_DIFFUSE,
+                                                 &lightprod_back_is_state_light[i][1]);
 
-         lightprod_front[i][2] = get_lightprod(p, i, 0, STATE_SPECULAR);
+         lightprod_front[i][2] = get_lightprod(p, i, 0, STATE_SPECULAR,
+                                               &lightprod_front_is_state_light[i][2]);
          if (twoside)
-            lightprod_back[i][2] = get_lightprod(p, i, 1, STATE_SPECULAR);
+            lightprod_back[i][2] = get_lightprod(p, i, 1, STATE_SPECULAR,
+                                                 &lightprod_back_is_state_light[i][2]);
       }
    }
 
@@ -1217,6 +1225,18 @@ static void build_lighting( struct tnl_program *p )
 	 /* Front face lighting:
 	  */
 	 {
+      /* Transform STATE_LIGHT into STATE_LIGHTPROD if needed. This isn't done in
+       * get_lightprod to avoid using too many temps.
+       */
+      for (int j = 0; j < 3; j++) {
+         if (lightprod_front_is_state_light[i][j]) {
+            struct ureg material_value = get_material(p, 0, STATE_AMBIENT + j);
+            struct ureg tmp = get_temp(p);
+            emit_op2(p, OPCODE_MUL, tmp, 0, lightprod_front[i][j], material_value);
+            lightprod_front[i][j] = tmp;
+         }
+      }
+
 	    struct ureg ambient = lightprod_front[i][0];
 	    struct ureg diffuse = lightprod_front[i][1];
 	    struct ureg specular = lightprod_front[i][2];
@@ -1272,6 +1292,18 @@ static void build_lighting( struct tnl_program *p )
 	 /* Back face lighting:
 	  */
 	 if (twoside) {
+      /* Transform STATE_LIGHT into STATE_LIGHTPROD if needed. This isn't done in
+       * get_lightprod to avoid using too many temps.
+       */
+      for (int j = 0; j < 3; j++) {
+         if (lightprod_back_is_state_light[i][j]) {
+            struct ureg material_value = get_material(p, 1, STATE_AMBIENT + j);
+            struct ureg tmp = get_temp(p);
+            emit_op2(p, OPCODE_MUL, tmp, 1, lightprod_back[i][j], material_value);
+            lightprod_back[i][j] = tmp;
+         }
+      }
+
 	    struct ureg ambient = lightprod_back[i][0];
 	    struct ureg diffuse = lightprod_back[i][1];
 	    struct ureg specular = lightprod_back[i][2];