Reflect the control flow graph from SPIR-V and check variable accesses

[libs/gl.git] / source / core / program.cpp

diff --git a/source/core/program.cpp b/source/core/program.cpp
index acdb20e88a5488063c3778a598af10f411b1b541..fdbfa6d4be08004f38be801c3a46c69ae0745b04 100644 (file)
--- a/source/core/program.cpp
+++ b/source/core/program.cpp
@@ -36,9 +36,11 @@ void Program::add_stages(const Module &mod, const map<string, int> &spec_values)
 
        if(mod.get_format()==Module::SPIR_V)
        {
-               collect_uniforms(static_cast<const SpirVModule &>(mod));
-               collect_attributes(static_cast<const SpirVModule &>(mod));
-               collect_builtins(static_cast<const SpirVModule &>(mod));
+               const SpirVModule &spirv_mod = static_cast<const SpirVModule &>(mod);
+               vector<uint8_t> used_variables = collect_used_variables(spirv_mod, spec_values);
+               collect_uniforms(spirv_mod, used_variables);
+               collect_attributes(spirv_mod, used_variables);
+               collect_builtins(spirv_mod);
        }
 
        finalize_uniforms();
@@ -49,15 +51,79 @@ void Program::add_stages(const Module &mod, const map<string, int> &spec_values)
                require_type(a.type);
 }
 
-void Program::collect_uniforms(const SpirVModule &mod)
+vector<uint8_t> Program::collect_used_variables(const SpirVModule &mod, const map<string, int> &spec_values)
+{
+       std::map<unsigned, int> spec_values_by_id;
+       for(const SpirVModule::Constant &c: mod.get_spec_constants())
+       {
+               auto i = spec_values.find(c.name);
+               if(i!=spec_values.end())
+                       spec_values_by_id[c.constant_id] = i->second;
+       }
+
+       const vector<SpirVModule::InstructionBlock> &blocks = mod.get_blocks();
+       vector<uint8_t> visited(blocks.size(), 4);
+       for(unsigned i=0; i<blocks.size(); ++i)
+       {
+               const SpirVModule::InstructionBlock &b = blocks[i];
+
+               bool cond = true;
+               if(b.condition)
+               {
+                       cond = b.condition->i_value;
+                       auto j = spec_values_by_id.find(b.condition->constant_id);
+                       if(j!=spec_values_by_id.end())
+                               cond = j->second;
+                       if(b.negate_condition)
+                               cond = !cond;
+               }
+
+               visited[i] |= cond*2;
+               for(const SpirVModule::InstructionBlock *s: b.successors)
+                       visited[s-blocks.data()] &= 3;
+       }
+
+       for(unsigned i=0; i<blocks.size(); ++i)
+               if(visited[i]&4)
+                       collect_visited_blocks(blocks, i, visited);
+
+       const vector<SpirVModule::Variable> &variables = mod.get_variables();
+       vector<uint8_t> used(variables.size());
+       for(unsigned i=0; i<blocks.size(); ++i)
+               if(visited[i]&1)
+               {
+                       for(const SpirVModule::Variable *v: blocks[i].accessed_variables)
+                               used[v-variables.data()] = 1;
+               }
+
+       return used;
+}
+
+void Program::collect_visited_blocks(const vector<SpirVModule::InstructionBlock> &blocks, unsigned i, vector<uint8_t> &visited)
+{
+       visited[i] |= 1;
+       for(const SpirVModule::InstructionBlock *s: blocks[i].successors)
+       {
+               unsigned j = s-blocks.data();
+               if((visited[j]&3)==2)
+                       collect_visited_blocks(blocks, j, visited);
+       }
+}
+
+void Program::collect_uniforms(const SpirVModule &mod, const vector<uint8_t> &used_variables)
 {
        // Prepare the default block
        reflect_data.uniform_blocks.push_back(ReflectData::UniformBlockInfo());
        vector<vector<string> > block_uniform_names(1);
 
+       const vector<SpirVModule::Variable> &variables = mod.get_variables();
        unsigned n_descriptor_sets = 0;
-       for(const SpirVModule::Variable &v: mod.get_variables())
+       for(unsigned i=0; i<variables.size(); ++i)
        {
+               if(!used_variables[i])
+                       continue;
+
+               const SpirVModule::Variable &v = variables[i];
                if((v.storage==SpirVModule::UNIFORM || v.storage==SpirVModule::PUSH_CONSTANT) && v.struct_type)
                {
                        reflect_data.uniform_blocks.push_back(ReflectData::UniformBlockInfo());
@@ -155,13 +221,14 @@ void Program::collect_block_uniforms(const SpirVModule::Structure &strct, const
        }
 }
 
-void Program::collect_attributes(const SpirVModule &mod)
+void Program::collect_attributes(const SpirVModule &mod, const vector<uint8_t> &used_variables)
 {
+       const vector<SpirVModule::Variable> &variables = mod.get_variables();
        for(const SpirVModule::EntryPoint &e: mod.get_entry_points())
                if(e.stage==SpirVModule::VERTEX && e.name=="main")
                {
                        for(const SpirVModule::Variable *v: e.globals)
-                               if(v->storage==SpirVModule::INPUT)
+                               if(v->storage==SpirVModule::INPUT && used_variables[v-variables.data()])
                                {
                                        reflect_data.attributes.push_back(ReflectData::AttributeInfo());
                                        ReflectData::AttributeInfo &info = reflect_data.attributes.back();