Cycles: keep track of SVM nodes used in kernels

To be used for specialization in Metal, to automatically leave out unused nodes
from the kernel.

Ref D14645

3 files changed, 14 insertions, 5 deletions

diff --git a/intern/cycles/scene/shader_nodes.cpp b/intern/cycles/scene/shader_nodes.cpp
index f93a1a5231a..bedb0fe2902 100644
--- a/intern/cycles/scene/shader_nodes.cpp
+++ b/intern/cycles/scene/shader_nodes.cpp
@@ -6671,7 +6671,7 @@ void CurvesNode::compile(SVMCompiler &compiler,
 
   ShaderInput *fac_in = input("Fac");
 
-  compiler.add_node(type,
+  compiler.add_node(ShaderNodeType(type),
                     compiler.encode_uchar4(compiler.stack_assign(fac_in),
                                            compiler.stack_assign(value_in),
                                            compiler.stack_assign(value_out),
@@ -6736,7 +6736,7 @@ void RGBCurvesNode::constant_fold(const ConstantFolder &folder)
 
 void RGBCurvesNode::compile(SVMCompiler &compiler)
 {
-  CurvesNode::compile(compiler, NODE_RGB_CURVES, input("Color"), output("Color"));
+  CurvesNode::compile(compiler, NODE_CURVES, input("Color"), output("Color"));
 }
 
 void RGBCurvesNode::compile(OSLCompiler &compiler)
@@ -6774,7 +6774,7 @@ void VectorCurvesNode::constant_fold(const ConstantFolder &folder)
 
 void VectorCurvesNode::compile(SVMCompiler &compiler)
 {
-  CurvesNode::compile(compiler, NODE_VECTOR_CURVES, input("Vector"), output("Vector"));
+  CurvesNode::compile(compiler, NODE_CURVES, input("Vector"), output("Vector"));
 }
 
 void VectorCurvesNode::compile(OSLCompiler &compiler)
diff --git a/intern/cycles/scene/svm.cpp b/intern/cycles/scene/svm.cpp
index 4bc5a1b9cc2..ede3f87e7e3 100644
--- a/intern/cycles/scene/svm.cpp
+++ b/intern/cycles/scene/svm.cpp
@@ -44,8 +44,6 @@ void SVMShaderManager::device_update_shader(Scene *scene,
   }
   assert(shader->graph);
 
-  svm_nodes->push_back_slow(make_int4(NODE_SHADER_JUMP, 0, 0, 0));
-
   SVMCompiler::Summary summary;
   SVMCompiler compiler(scene);
   compiler.background = (shader == scene->background->get_shader(scene));
@@ -170,6 +168,9 @@ SVMCompiler::SVMCompiler(Scene *scene) : scene(scene)
   background = false;
   mix_weight_offset = SVM_STACK_INVALID;
   compile_failed = false;
+
+  /* This struct has one entry for every node, in order of ShaderNodeType definition. */
+  svm_node_types_used = (std::atomic_int *)&scene->dscene.data.svm_usage;
 }
 
 int SVMCompiler::stack_size(SocketType::Type type)
@@ -378,11 +379,13 @@ void SVMCompiler::add_node(int a, int b, int c, int d)
 
 void SVMCompiler::add_node(ShaderNodeType type, int a, int b, int c)
 {
+  svm_node_types_used[type] = true;
   current_svm_nodes.push_back_slow(make_int4(type, a, b, c));
 }
 
 void SVMCompiler::add_node(ShaderNodeType type, const float3 &f)
 {
+  svm_node_types_used[type] = true;
   current_svm_nodes.push_back_slow(
       make_int4(type, __float_as_int(f.x), __float_as_int(f.y), __float_as_int(f.z)));
 }
@@ -663,6 +666,7 @@ void SVMCompiler::generate_multi_closure(ShaderNode *root_node,
         /* Add instruction to skip closure and its dependencies if mix
          * weight is zero.
          */
+        svm_node_types_used[NODE_JUMP_IF_ONE] = true;
         current_svm_nodes.push_back_slow(make_int4(NODE_JUMP_IF_ONE, 0, stack_assign(facin), 0));
         int node_jump_skip_index = current_svm_nodes.size() - 1;
 
@@ -678,6 +682,7 @@ void SVMCompiler::generate_multi_closure(ShaderNode *root_node,
         /* Add instruction to skip closure and its dependencies if mix
          * weight is zero.
          */
+        svm_node_types_used[NODE_JUMP_IF_ZERO] = true;
         current_svm_nodes.push_back_slow(make_int4(NODE_JUMP_IF_ZERO, 0, stack_assign(facin), 0));
         int node_jump_skip_index = current_svm_nodes.size() - 1;
 
@@ -844,6 +849,9 @@ void SVMCompiler::compile_type(Shader *shader, ShaderGraph *graph, ShaderType ty
 
 void SVMCompiler::compile(Shader *shader, array<int4> &svm_nodes, int index, Summary *summary)
 {
+  svm_node_types_used[NODE_SHADER_JUMP] = true;
+  svm_nodes.push_back_slow(make_int4(NODE_SHADER_JUMP, 0, 0, 0));
+
   /* copy graph for shader with bump mapping */
   ShaderNode *output = shader->graph->output();
   int start_num_svm_nodes = svm_nodes.size();
diff --git a/intern/cycles/scene/svm.h b/intern/cycles/scene/svm.h
index 19746616207..f72375e7f87 100644
--- a/intern/cycles/scene/svm.h
+++ b/intern/cycles/scene/svm.h
@@ -211,6 +211,7 @@ class SVMCompiler {
   /* compile */
   void compile_type(Shader *shader, ShaderGraph *graph, ShaderType type);
 
+  std::atomic_int *svm_node_types_used;
   array<int4> current_svm_nodes;
   ShaderType current_type;
   Shader *current_shader;