]> git.tdb.fi Git - libs/gl.git/blobdiff - source/programcompiler.cpp
Remove conditionals and loops that can be determined to never run
[libs/gl.git] / source / programcompiler.cpp
index a730f74348f072fab4edd1398835b380b4295af4..9b3266755b0b4f36c7bdc1ebe3471ebba48e8d40 100644 (file)
@@ -4,6 +4,7 @@
 #include "error.h"
 #include "program.h"
 #include "programcompiler.h"
+#include "resources.h"
 #include "shader.h"
 
 using namespace std;
@@ -34,17 +35,20 @@ namespace GL {
 using namespace ProgramSyntax;
 
 ProgramCompiler::ProgramCompiler():
+       resources(0),
        module(0)
 { }
 
 void ProgramCompiler::compile(const string &source)
 {
+       resources = 0;
        module = &parser.parse(source);
        process();
 }
 
-void ProgramCompiler::compile(IO::Base &io)
+void ProgramCompiler::compile(IO::Base &io, Resources *res)
 {
+       resources = res;
        module = &parser.parse(io);
        process();
 }
@@ -58,11 +62,11 @@ void ProgramCompiler::add_shaders(Program &program)
        for(list<Stage>::iterator i=module->stages.begin(); i!=module->stages.end(); ++i)
        {
                if(i->type==VERTEX)
-                       program.attach_shader_owned(new VertexShader(head+create_source(*i)));
+                       program.attach_shader_owned(new VertexShader(head+apply<Formatter>(*i)));
                else if(i->type==GEOMETRY)
-                       program.attach_shader_owned(new GeometryShader(head+create_source(*i)));
+                       program.attach_shader_owned(new GeometryShader(head+apply<Formatter>(*i)));
                else if(i->type==FRAGMENT)
-                       program.attach_shader_owned(new FragmentShader(head+create_source(*i)));
+                       program.attach_shader_owned(new FragmentShader(head+apply<Formatter>(*i)));
        }
 
        program.bind_attribute(VERTEX4, "vertex");
@@ -102,6 +106,11 @@ Stage *ProgramCompiler::get_builtins(StageType type)
 
 void ProgramCompiler::process()
 {
+       list<Import *> imports = apply<NodeGatherer<Import> >(module->shared);
+       for(list<Import *>::iterator i=imports.end(); i!=imports.begin(); )
+               import((*--i)->module);
+       apply<NodeRemover>(module->shared, set<Node *>(imports.begin(), imports.end()));
+
        for(list<Stage>::iterator i=module->stages.begin(); i!=module->stages.end(); ++i)
                generate(*i);
        for(list<Stage>::iterator i=module->stages.begin(); i!=module->stages.end(); )
@@ -113,6 +122,39 @@ void ProgramCompiler::process()
        }
 }
 
+void ProgramCompiler::import(const string &name)
+{
+       if(!resources)
+               throw runtime_error("no resources");
+       RefPtr<IO::Seekable> io = resources->open_raw(name+".glsl");
+       if(!io)
+               throw runtime_error(format("module %s not found", name));
+       ProgramParser import_parser;
+       Module &imported_module = import_parser.parse(*io);
+
+       inject_block(module->shared.content, imported_module.shared.content);
+       apply<DeclarationCombiner>(module->shared);
+       for(list<Stage>::iterator i=imported_module.stages.begin(); i!=imported_module.stages.end(); ++i)
+       {
+               list<Stage>::iterator j;
+               for(j=module->stages.begin(); (j!=module->stages.end() && j->type<i->type); ++j) ;
+               if(j==module->stages.end() || j->type>i->type)
+               {
+                       j = module->stages.insert(j, *i);
+                       list<Stage>::iterator k = j;
+                       if(++k!=module->stages.end())
+                               k->previous = &*j;
+                       if(j!=module->stages.begin())
+                               j->previous = &*--(k=j);
+               }
+               else
+               {
+                       inject_block(j->content, i->content);
+                       apply<DeclarationCombiner>(*j);
+               }
+       }
+}
+
 void ProgramCompiler::generate(Stage &stage)
 {
        inject_block(stage.content, module->shared.content);
@@ -125,14 +167,13 @@ void ProgramCompiler::generate(Stage &stage)
 
 bool ProgramCompiler::optimize(Stage &stage)
 {
-       UnusedVariableLocator unused_locator;
-       unused_locator.apply(stage);
+       apply<ConstantConditionEliminator>(stage);
+       apply<VariableResolver>(stage);
 
-       NodeRemover remover;
-       remover.to_remove = unused_locator.unused_nodes;
-       remover.apply(stage);
+       set<Node *> unused = apply<UnusedVariableLocator>(stage);
+       apply<NodeRemover>(stage, unused);
 
-       return !unused_locator.unused_nodes.empty();
+       return !unused.empty();
 }
 
 void ProgramCompiler::inject_block(Block &target, const Block &source)
@@ -143,17 +184,19 @@ void ProgramCompiler::inject_block(Block &target, const Block &source)
 }
 
 template<typename T>
-void ProgramCompiler::apply(Stage &stage)
+typename T::ResultType ProgramCompiler::apply(Stage &stage)
 {
        T visitor;
        visitor.apply(stage);
+       return visitor.get_result();
 }
 
-string ProgramCompiler::create_source(Stage &stage)
+template<typename T, typename A>
+typename T::ResultType ProgramCompiler::apply(Stage &stage, const A &arg)
 {
-       Formatter formatter;
-       formatter.apply(stage);
-       return formatter.formatted;
+       T visitor(arg);
+       visitor.apply(stage);
+       return visitor.get_result();
 }
 
 
@@ -264,6 +307,11 @@ void ProgramCompiler::Formatter::visit(Block &block)
                formatted += format("\n%s}", string(brace_indent*2, ' '));
 }
 
+void ProgramCompiler::Formatter::visit(Import &import)
+{
+       formatted += format("import %s;", import.module);
+}
+
 void ProgramCompiler::Formatter::visit(Layout &layout)
 {
        formatted += "layout(";
@@ -329,7 +377,7 @@ void ProgramCompiler::Formatter::visit(FunctionDeclaration &func)
                (*i)->visit(*this);
        }
        formatted += ')';
-       if(func.definition)
+       if(func.definition==&func)
        {
                formatted += '\n';
                func.body.visit(*this);
@@ -378,6 +426,56 @@ void ProgramCompiler::Formatter::visit(Return &ret)
 }
 
 
+ProgramCompiler::DeclarationCombiner::DeclarationCombiner():
+       toplevel(true),
+       remove_node(false)
+{ }
+
+void ProgramCompiler::DeclarationCombiner::visit(Block &block)
+{
+       if(!toplevel)
+               return;
+
+       SetForScope<bool> set(toplevel, false);
+       for(list<NodePtr<Node> >::iterator i=block.body.begin(); i!=block.body.end(); )
+       {
+               remove_node = false;
+               (*i)->visit(*this);
+               if(remove_node)
+                       block.body.erase(i++);
+               else
+                       ++i;
+       }
+}
+
+void ProgramCompiler::DeclarationCombiner::visit(FunctionDeclaration &func)
+{
+       vector<FunctionDeclaration *> &decls = functions[func.name];
+       if(func.definition)
+       {
+               for(vector<FunctionDeclaration *>::iterator i=decls.begin(); i!=decls.end(); ++i)
+               {
+                       (*i)->definition = func.definition;
+                       (*i)->body.body.clear();
+               }
+       }
+       decls.push_back(&func);
+}
+
+void ProgramCompiler::DeclarationCombiner::visit(VariableDeclaration &var)
+{
+       VariableDeclaration *&ptr = variables[var.name];
+       if(ptr)
+       {
+               if(var.init_expression)
+                       ptr->init_expression = var.init_expression;
+               remove_node = true;
+       }
+       else
+               ptr = &var;
+}
+
+
 ProgramCompiler::VariableResolver::VariableResolver():
        anonymous(false),
        record_target(false),
@@ -744,6 +842,162 @@ void ProgramCompiler::VariableRenamer::visit(VariableDeclaration &var)
 }
 
 
+ProgramCompiler::ExpressionEvaluator::ExpressionEvaluator():
+       variable_values(0),
+       result(0.0f),
+       result_valid(false)
+{ }
+
+ProgramCompiler::ExpressionEvaluator::ExpressionEvaluator(const ValueMap &v):
+       variable_values(&v),
+       result(0.0f),
+       result_valid(false)
+{ }
+
+void ProgramCompiler::ExpressionEvaluator::visit(Literal &literal)
+{
+       if(literal.token=="true")
+               result = 1.0f;
+       else if(literal.token=="false")
+               result = 0.0f;
+       else
+               result = lexical_cast<float>(literal.token);
+       result_valid = true;
+}
+
+void ProgramCompiler::ExpressionEvaluator::visit(VariableReference &var)
+{
+       if(!var.declaration)
+               return;
+
+       if(variable_values)
+       {
+               ValueMap::const_iterator i = variable_values->find(var.declaration);
+               if(i!=variable_values->end())
+                       i->second->visit(*this);
+       }
+       else if(var.declaration->init_expression)
+               var.declaration->init_expression->visit(*this);
+}
+
+void ProgramCompiler::ExpressionEvaluator::visit(UnaryExpression &unary)
+{
+       result_valid = false;
+       unary.expression->visit(*this);
+       if(!result_valid)
+               return;
+
+       if(unary.oper=="!")
+               result = !result;
+       else
+               result_valid = false;
+}
+
+void ProgramCompiler::ExpressionEvaluator::visit(BinaryExpression &binary)
+{
+       result_valid = false;
+       binary.left->visit(*this);
+       if(!result_valid)
+               return;
+
+       float left_result = result;
+       result_valid = false;
+       binary.right->visit(*this);
+       if(!result_valid)
+               return;
+
+       if(binary.oper=="<")
+               result = (left_result<result);
+       else if(binary.oper=="<=")
+               result = (left_result<=result);
+       else if(binary.oper==">")
+               result = (left_result>result);
+       else if(binary.oper==">=")
+               result = (left_result>=result);
+       else if(binary.oper=="==")
+               result = (left_result==result);
+       else if(binary.oper=="!=")
+               result = (left_result!=result);
+       else if(binary.oper=="&&")
+               result = (left_result && result);
+       else if(binary.oper=="||")
+               result = (left_result || result);
+       else
+               result_valid = false;
+}
+
+
+ProgramCompiler::ConstantConditionEliminator::ConstantConditionEliminator():
+       scope_level(0),
+       remove_node(false),
+       replacement_block(0)
+{ }
+
+void ProgramCompiler::ConstantConditionEliminator::visit(Block &block)
+{
+       SetForScope<unsigned> set(scope_level, scope_level+1);
+       for(list<NodePtr<Node> >::iterator i=block.body.begin(); i!=block.body.end(); )
+       {
+               (*i)->visit(*this);
+               if(replacement_block)
+               {
+                       for(list<NodePtr<Node> >::iterator j=replacement_block->body.begin(); j!=replacement_block->body.end(); ++j)
+                               block.body.insert(i, *j);
+                       replacement_block = 0;
+               }
+
+               if(remove_node)
+                       block.body.erase(i++);
+               else
+                       ++i;
+               remove_node = false;
+       }
+
+       for(map<string, VariableDeclaration *>::const_iterator i=block.variables.begin(); i!=block.variables.end(); ++i)
+               variable_values.erase(i->second);
+}
+
+void ProgramCompiler::ConstantConditionEliminator::visit(Assignment &assign)
+{
+       variable_values.erase(assign.target_declaration);
+}
+
+void ProgramCompiler::ConstantConditionEliminator::visit(VariableDeclaration &var)
+{
+       if(var.constant || scope_level>1)
+               variable_values[&var] = &*var.init_expression;
+}
+
+void ProgramCompiler::ConstantConditionEliminator::visit(Conditional &cond)
+{
+       ExpressionEvaluator eval(variable_values);
+       cond.condition->visit(eval);
+       if(eval.result_valid)
+       {
+               remove_node = true;
+               replacement_block = (eval.result ? &cond.body : &cond.else_body);
+       }
+       else
+               TraversingVisitor::visit(cond);
+}
+
+void ProgramCompiler::ConstantConditionEliminator::visit(Iteration &iter)
+{
+       if(iter.condition)
+       {
+               ExpressionEvaluator eval;
+               iter.condition->visit(eval);
+               if(eval.result_valid && !eval.result)
+               {
+                       remove_node = true;
+                       return;
+               }
+       }
+
+       TraversingVisitor::visit(iter);
+}
+
+
 ProgramCompiler::UnusedVariableLocator::UnusedVariableLocator():
        aggregate(0),
        assignment(0),
@@ -944,6 +1198,10 @@ void ProgramCompiler::UnusedVariableLocator::visit(Iteration &iter)
 }
 
 
+ProgramCompiler::NodeRemover::NodeRemover(const set<Node *> &r):
+       to_remove(r)
+{ }
+
 void ProgramCompiler::NodeRemover::visit(Block &block)
 {
        for(list<NodePtr<Node> >::iterator i=block.body.begin(); i!=block.body.end(); )