X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fglsl%2Foptimize.cpp;h=c1431f2b6e9d9e33ed522cd853bcd326bbb3414a;hb=041ba4b1acd55337239c5ce24cc310118c621206;hp=d26c6e2d519179ac531dd2a635c85e605d98e9e8;hpb=d5c7c7f0b15c407b3da2184936e6deed18554c6a;p=libs%2Fgl.git diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp index d26c6e2d..c1431f2b 100644 --- a/source/glsl/optimize.cpp +++ b/source/glsl/optimize.cpp @@ -1,4 +1,5 @@ #include +#include #include "optimize.h" using namespace std; @@ -22,6 +23,8 @@ void InlineableFunctionLocator::visit(FunctionCall &call) { unsigned &count = refcounts[def]; ++count; + /* Don't inline functions which are called more than once or are called + recursively. */ if(count>1 || def==current_function) inlineable.erase(def); } @@ -40,18 +43,21 @@ void InlineableFunctionLocator::visit(FunctionDeclaration &func) TraversingVisitor::visit(func); } -void InlineableFunctionLocator::visit(Conditional &) +void InlineableFunctionLocator::visit(Conditional &cond) { + TraversingVisitor::visit(cond); inlineable.erase(current_function); } -void InlineableFunctionLocator::visit(Iteration &) +void InlineableFunctionLocator::visit(Iteration &iter) { + TraversingVisitor::visit(iter); inlineable.erase(current_function); } -void InlineableFunctionLocator::visit(Return &) +void InlineableFunctionLocator::visit(Return &ret) { + TraversingVisitor::visit(ret); if(return_count) inlineable.erase(current_function); ++return_count; @@ -64,25 +70,25 @@ InlineContentInjector::InlineContentInjector(): deps_only(false) { } -const string &InlineContentInjector::apply(Stage &stage, FunctionDeclaration &target_func, Block &tgtb, const NodeList::iterator &ins_pt, FunctionDeclaration &src) +const string &InlineContentInjector::apply(Stage &stage, FunctionDeclaration &target_func, Block &tgt_blk, const NodeList::iterator &ins_pt, FunctionDeclaration &src) { - target_block = &tgtb; + target_block = &tgt_blk; source_func = &src; for(NodeList::iterator i=src.body.body.begin(); i!=src.body.body.end(); ++i) { - inlined_statement = 0; + r_inlined_statement = 0; (*i)->visit(*this); - if(!inlined_statement) - inlined_statement = (*i)->clone(); + if(!r_inlined_statement) + r_inlined_statement = (*i)->clone(); SetFlag set_remap(remap_names); - inlined_statement->visit(*this); - tgtb.body.insert(ins_pt, inlined_statement); + r_inlined_statement->visit(*this); + tgt_blk.body.insert(ins_pt, r_inlined_statement); } NodeReorderer().apply(stage, target_func, dependencies); - return result_name; + return r_result_name; } string InlineContentInjector::create_unused_name(const string &base, bool always_prefix) @@ -147,7 +153,7 @@ void InlineContentInjector::visit(VariableDeclaration &var) { RefPtr inlined_var = var.clone(); inlined_var->name = create_unused_name(var.name, false); - inlined_statement = inlined_var; + r_inlined_statement = inlined_var; variable_map[var.name] = inlined_var.get(); } @@ -159,45 +165,49 @@ void InlineContentInjector::visit(Return &ret) if(ret.expression) { - result_name = create_unused_name("return", true); + /* Create a new variable to hold the return value of the inlined + function. */ + r_result_name = create_unused_name("return", true); RefPtr var = new VariableDeclaration; var->source = ret.source; var->line = ret.line; var->type = source_func->return_type; - var->name = result_name; + var->name = r_result_name; var->init_expression = ret.expression->clone(); - inlined_statement = var; + r_inlined_statement = var; } } FunctionInliner::FunctionInliner(): current_function(0), - any_inlined(false) + r_any_inlined(false) { } bool FunctionInliner::apply(Stage &s) { stage = &s; inlineable = InlineableFunctionLocator().apply(s); - any_inlined = false; + r_any_inlined = false; s.content.visit(*this); - return any_inlined; + return r_any_inlined; } void FunctionInliner::visit_and_inline(RefPtr &ptr) { - inline_result = 0; + r_inline_result = 0; ptr->visit(*this); - if(inline_result) + if(r_inline_result) { - ptr = inline_result; - any_inlined = true; + ptr = r_inline_result; + r_any_inlined = true; } + r_inline_result = 0; } void FunctionInliner::visit(Block &block) { + SetForScope set_block(current_block, &block); SetForScope::iterator> save_insert_point(insert_point, block.body.begin()); for(NodeList::iterator i=block.body.begin(); i!=block.body.end(); ++i) { @@ -209,20 +219,17 @@ void FunctionInliner::visit(Block &block) void FunctionInliner::visit(UnaryExpression &unary) { visit_and_inline(unary.expression); - inline_result = 0; } void FunctionInliner::visit(BinaryExpression &binary) { visit_and_inline(binary.left); visit_and_inline(binary.right); - inline_result = 0; } void FunctionInliner::visit(MemberAccess &memacc) { visit_and_inline(memacc.left); - inline_result = 0; } void FunctionInliner::visit(FunctionCall &call) @@ -238,20 +245,18 @@ void FunctionInliner::visit(FunctionCall &call) { string result_name = InlineContentInjector().apply(*stage, *current_function, *current_block, insert_point, *def); - // This will later get removed by UnusedVariableRemover + // This will later get removed by UnusedVariableRemover. if(result_name.empty()) result_name = "msp_unused_from_inline"; RefPtr ref = new VariableReference; ref->name = result_name; - inline_result = ref; + r_inline_result = ref; /* Inlined variables need to be resolved before this function can be inlined further. */ inlineable.erase(current_function); } - else - inline_result = 0; } void FunctionInliner::visit(ExpressionStatement &expr) @@ -263,7 +268,6 @@ void FunctionInliner::visit(VariableDeclaration &var) { if(var.init_expression) visit_and_inline(var.init_expression); - inline_result = 0; } void FunctionInliner::visit(FunctionDeclaration &func) @@ -272,6 +276,26 @@ void FunctionInliner::visit(FunctionDeclaration &func) TraversingVisitor::visit(func); } +void FunctionInliner::visit(Conditional &cond) +{ + visit_and_inline(cond.condition); + cond.body.visit(*this); +} + +void FunctionInliner::visit(Iteration &iter) +{ + /* Visit the initialization statement before entering the loop body so the + inlined statements get inserted outside. */ + if(iter.init_statement) + iter.init_statement->visit(*this); + + SetForScope set_block(current_block, &iter.body); + /* Skip the condition and loop expression parts because they're not properly + inside the body block. Inlining anything into them will require a more + comprehensive transformation. */ + iter.body.visit(*this); +} + void FunctionInliner::visit(Return &ret) { if(ret.expression) @@ -279,66 +303,282 @@ void FunctionInliner::visit(Return &ret) } -ConstantConditionEliminator::ConstantConditionEliminator(): - record_only(false) +ExpressionInliner::ExpressionInfo::ExpressionInfo(): + expression(0), + assign_scope(0), + inline_point(0), + inner_oper(0), + outer_oper(0), + inline_on_rhs(false), + trivial(false), + available(true) { } -void ConstantConditionEliminator::apply(Stage &stage) + +ExpressionInliner::ExpressionInliner(): + r_ref_info(0), + r_any_inlined(false), + r_trivial(false), + mutating(false), + iteration_init(false), + iteration_body(0), + r_oper(0) +{ } + +bool ExpressionInliner::apply(Stage &s) { - stage.content.visit(*this); - NodeRemover().apply(stage, nodes_to_remove); + s.content.visit(*this); + return r_any_inlined; } -void ConstantConditionEliminator::visit(Block &block) +void ExpressionInliner::visit_and_record(RefPtr &ptr, const Operator *outer_oper, bool on_rhs) { - SetForScope set_block(current_block, &block); - for(NodeList::iterator i=block.body.begin(); i!=block.body.end(); ++i) + r_ref_info = 0; + ptr->visit(*this); + if(r_ref_info && r_ref_info->expression && r_ref_info->available) { - insert_point = i; - (*i)->visit(*this); + if(iteration_body && !r_ref_info->trivial) + { + /* Don't inline non-trivial expressions which were assigned outside + an iteration statement. The iteration may run multiple times, which + would cause the expression to also be evaluated multiple times. */ + Block *i = r_ref_info->assign_scope; + for(; (i && i!=iteration_body); i=i->parent) ; + if(!i) + return; + } + + r_ref_info->outer_oper = outer_oper; + if(r_ref_info->trivial) + inline_expression(*r_ref_info->expression, ptr, outer_oper, r_ref_info->inner_oper, on_rhs); + else + { + /* Record the inline point for a non-trivial expression but don't + inline it yet. It might turn out it shouldn't be inlined after all. */ + r_ref_info->inline_point = &ptr; + r_ref_info->inline_on_rhs = on_rhs; + } + } + r_ref_info = 0; +} + +void ExpressionInliner::inline_expression(Expression &expr, RefPtr &ptr, const Operator *outer_oper, const Operator *inner_oper, bool on_rhs) +{ + unsigned outer_precedence = (outer_oper ? outer_oper->precedence : 20); + unsigned inner_precedence = (inner_oper ? inner_oper->precedence : 0); + + bool needs_parentheses = (inner_precedence>=outer_precedence); + if(inner_oper && inner_oper==outer_oper) + // Omit parentheses if the operator's natural grouping works out. + needs_parentheses = (inner_oper->assoc!=Operator::ASSOCIATIVE && on_rhs!=(inner_oper->assoc==Operator::RIGHT_TO_LEFT)); + + if(needs_parentheses) + { + RefPtr parexpr = new ParenthesizedExpression; + parexpr->expression = expr.clone(); + ptr = parexpr; + } + else + ptr = expr.clone(); + + r_any_inlined = true; +} + +void ExpressionInliner::visit(Block &block) +{ + TraversingVisitor::visit(block); + + for(map::iterator i=expressions.begin(); i!=expressions.end(); ) + { + map::iterator j = block.variables.find(i->first->name); + if(j!=block.variables.end() && j->second==i->first) + { + if(i->second.expression && i->second.inline_point) + inline_expression(*i->second.expression, *i->second.inline_point, i->second.outer_oper, i->second.inner_oper, i->second.inline_on_rhs); + + expressions.erase(i++); + } + else + { + /* The expression was assigned in this block and may depend on local + variables of the block. If this is a conditionally executed block, + the assignment might not always happen. Mark the expression as not + available to any outer blocks. */ + if(i->second.assign_scope==&block) + i->second.available = false; + + ++i; + } } +} - for(map::const_iterator i=block.variables.begin(); i!=block.variables.end(); ++i) - variable_values.erase(i->second); +void ExpressionInliner::visit(VariableReference &var) +{ + if(var.declaration) + { + map::iterator i = expressions.find(var.declaration); + if(i!=expressions.end()) + { + /* If a non-trivial expression is referenced multiple times, don't + inline it. */ + if(i->second.inline_point && !i->second.trivial) + i->second.expression = 0; + /* Mutating expressions are analogous to self-referencing assignments + and prevent inlining. */ + if(mutating) + i->second.expression = 0; + r_ref_info = &i->second; + } + } +} + +void ExpressionInliner::visit(MemberAccess &memacc) +{ + visit_and_record(memacc.left, memacc.oper, false); + r_oper = memacc.oper; + r_trivial = false; +} + +void ExpressionInliner::visit(UnaryExpression &unary) +{ + SetFlag set_target(mutating, mutating || unary.oper->token[1]=='+' || unary.oper->token[1]=='-'); + visit_and_record(unary.expression, unary.oper, false); + r_oper = unary.oper; + r_trivial = false; +} + +void ExpressionInliner::visit(BinaryExpression &binary) +{ + visit_and_record(binary.left, binary.oper, false); + { + SetFlag clear_target(mutating, false); + visit_and_record(binary.right, binary.oper, true); + } + r_oper = binary.oper; + r_trivial = false; } -void ConstantConditionEliminator::visit(UnaryExpression &unary) +void ExpressionInliner::visit(Assignment &assign) { - if(VariableReference *var = dynamic_cast(unary.expression.get())) - if(unary.oper=="++" || unary.oper=="--") - variable_values.erase(var->declaration); + { + SetFlag set_target(mutating); + visit_and_record(assign.left, assign.oper, false); + } + r_oper = 0; + visit_and_record(assign.right, assign.oper, true); + + if(assign.target_declaration) + { + map::iterator i = expressions.find(assign.target_declaration); + if(i!=expressions.end()) + { + /* Self-referencing assignments can't be inlined without additional + work. Just clear any previous expression. */ + i->second.expression = (assign.self_referencing ? 0 : assign.right.get()); + i->second.assign_scope = current_block; + i->second.inline_point = 0; + i->second.inner_oper = r_oper; + i->second.available = true; + } + } + + r_oper = assign.oper; + r_trivial = false; } -void ConstantConditionEliminator::visit(Assignment &assign) +void ExpressionInliner::visit(FunctionCall &call) { - variable_values.erase(assign.target_declaration); + for(NodeArray::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i) + visit_and_record(*i, 0, false); + r_oper = 0; + r_trivial = false; } -void ConstantConditionEliminator::visit(VariableDeclaration &var) +void ExpressionInliner::visit(VariableDeclaration &var) { + r_oper = 0; + r_trivial = true; + if(var.init_expression) + visit_and_record(var.init_expression, 0, false); + bool constant = var.constant; if(constant && var.layout) { for(vector::const_iterator i=var.layout->qualifiers.begin(); (constant && i!=var.layout->qualifiers.end()); ++i) constant = (i->name!="constant_id"); } - if((constant || current_block->parent) && var.init_expression) - variable_values[&var] = var.init_expression.get(); + + /* Only inline global variables if they're constant and have trivial + initializers. Non-constant variables could change in ways which are hard to + analyze and non-trivial expressions could be expensive to inline. */ + if((current_block->parent || (constant && r_trivial)) && var.interface.empty()) + { + ExpressionInfo &info = expressions[&var]; + /* Assume variables declared in an iteration initialization statement + will have their values change throughout the iteration. */ + info.expression = (iteration_init ? 0 : var.init_expression.get()); + info.assign_scope = current_block; + info.inner_oper = r_oper; + info.trivial = r_trivial; + } +} + +void ExpressionInliner::visit(Conditional &cond) +{ + visit_and_record(cond.condition, 0, false); + cond.body.visit(*this); +} + +void ExpressionInliner::visit(Iteration &iter) +{ + SetForScope set_block(current_block, &iter.body); + if(iter.init_statement) + { + SetFlag set_init(iteration_init); + iter.init_statement->visit(*this); + } + + SetForScope set_body(iteration_body, &iter.body); + if(iter.condition) + iter.condition->visit(*this); + iter.body.visit(*this); + if(iter.loop_expression) + iter.loop_expression->visit(*this); +} + +void ExpressionInliner::visit(Return &ret) +{ + if(ret.expression) + visit_and_record(ret.expression, 0, false); +} + + +void ConstantConditionEliminator::apply(Stage &stage) +{ + stage.content.visit(*this); + NodeRemover().apply(stage, nodes_to_remove); +} + +void ConstantConditionEliminator::visit(Block &block) +{ + SetForScope set_block(current_block, &block); + for(NodeList::iterator i=block.body.begin(); i!=block.body.end(); ++i) + { + insert_point = i; + (*i)->visit(*this); + } } void ConstantConditionEliminator::visit(Conditional &cond) { - if(!record_only) + ExpressionEvaluator eval; + cond.condition->visit(eval); + if(eval.is_result_valid()) { - ExpressionEvaluator eval(variable_values); - cond.condition->visit(eval); - if(eval.is_result_valid()) - { - Block &block = (eval.get_result() ? cond.body : cond.else_body); - current_block->body.splice(insert_point, block.body); - nodes_to_remove.insert(&cond); - return; - } + Block &block = (eval.get_result() ? cond.body : cond.else_body); + current_block->body.splice(insert_point, block.body); + nodes_to_remove.insert(&cond); + return; } TraversingVisitor::visit(cond); @@ -346,33 +586,23 @@ void ConstantConditionEliminator::visit(Conditional &cond) void ConstantConditionEliminator::visit(Iteration &iter) { - if(!record_only) + if(iter.condition) { - if(iter.condition) + /* If the loop condition is always false on the first iteration, the + entire loop can be removed */ + ExpressionEvaluator::ValueMap values; + if(VariableDeclaration *var = dynamic_cast(iter.init_statement.get())) + values[var] = var->init_expression.get(); + ExpressionEvaluator eval(values); + iter.condition->visit(eval); + if(eval.is_result_valid() && !eval.get_result()) { - /* If the loop condition is always false on the first iteration, the - entire loop can be removed */ - if(iter.init_statement) - iter.init_statement->visit(*this); - ExpressionEvaluator eval(variable_values); - iter.condition->visit(eval); - if(eval.is_result_valid() && !eval.get_result()) - { - nodes_to_remove.insert(&iter); - return; - } + nodes_to_remove.insert(&iter); + return; } - - /* Record all assignments that occur inside the loop body so those - variables won't be considered as constant */ - SetFlag set_record(record_only); - TraversingVisitor::visit(iter); } TraversingVisitor::visit(iter); - - if(VariableDeclaration *init_decl = dynamic_cast(iter.init_statement.get())) - variable_values.erase(init_decl); } @@ -383,12 +613,79 @@ UnusedVariableRemover::VariableInfo::VariableInfo(): { } +bool UnusedTypeRemover::apply(Stage &stage) +{ + stage.content.visit(*this); + NodeRemover().apply(stage, unused_nodes); + return !unused_nodes.empty(); +} + +void UnusedTypeRemover::visit(Literal &literal) +{ + unused_nodes.erase(literal.type); +} + +void UnusedTypeRemover::visit(UnaryExpression &unary) +{ + unused_nodes.erase(unary.type); + TraversingVisitor::visit(unary); +} + +void UnusedTypeRemover::visit(BinaryExpression &binary) +{ + unused_nodes.erase(binary.type); + TraversingVisitor::visit(binary); +} + +void UnusedTypeRemover::visit(FunctionCall &call) +{ + unused_nodes.erase(call.type); + TraversingVisitor::visit(call); +} + +void UnusedTypeRemover::visit(BasicTypeDeclaration &type) +{ + if(type.base_type) + unused_nodes.erase(type.base_type); + unused_nodes.insert(&type); +} + +void UnusedTypeRemover::visit(ImageTypeDeclaration &type) +{ + if(type.base_type) + unused_nodes.erase(type.base_type); + unused_nodes.insert(&type); +} + +void UnusedTypeRemover::visit(StructDeclaration &strct) +{ + unused_nodes.insert(&strct); + TraversingVisitor::visit(strct); +} + +void UnusedTypeRemover::visit(VariableDeclaration &var) +{ + unused_nodes.erase(var.type_declaration); +} + +void UnusedTypeRemover::visit(InterfaceBlock &iface) +{ + unused_nodes.erase(iface.type_declaration); +} + +void UnusedTypeRemover::visit(FunctionDeclaration &func) +{ + unused_nodes.erase(func.return_type_declaration); + TraversingVisitor::visit(func); +} + + UnusedVariableRemover::UnusedVariableRemover(): aggregate(0), - assignment(0), + r_assignment(0), assignment_target(false), - assign_to_subscript(false), - side_effects(false) + r_assign_to_subfield(false), + r_side_effects(false) { } bool UnusedVariableRemover::apply(Stage &stage) @@ -398,8 +695,22 @@ bool UnusedVariableRemover::apply(Stage &stage) BlockVariableMap &global_variables = variables.back(); for(BlockVariableMap::iterator i=global_variables.begin(); i!=global_variables.end(); ++i) { - if(i->first->interface=="out" && (stage.type==Stage::FRAGMENT || i->first->linked_declaration || !i->first->name.compare(0, 3, "gl_"))) + string interface = i->first->interface; + bool linked = i->first->linked_declaration; + map::iterator j = aggregates.find(i->first); + if(j!=aggregates.end()) + if(InterfaceBlock *iface = dynamic_cast(j->second)) + { + interface = iface->interface; + linked = iface->linked_block; + } + + /* Don't remove output variables which are used by the next stage or the + graphics API. */ + if(interface=="out" && (stage.type==Stage::FRAGMENT || linked || !i->first->name.compare(0, 3, "gl_"))) continue; + + // Mark other unreferenced global variables as unused. if(!i->second.referenced) { unused_nodes.insert(i->first); @@ -422,6 +733,7 @@ void UnusedVariableRemover::visit(VariableReference &var) if(var.declaration && !assignment_target) { VariableInfo &var_info = variables.back()[var.declaration]; + // Previous assignments are used by this reference. clear_assignments(var_info, false); var_info.referenced = true; } @@ -434,6 +746,8 @@ void UnusedVariableRemover::visit(InterfaceBlockReference &iface) void UnusedVariableRemover::visit(MemberAccess &memacc) { + if(assignment_target) + r_assign_to_subfield = true; TraversingVisitor::visit(memacc); unused_nodes.erase(memacc.declaration); } @@ -441,18 +755,18 @@ void UnusedVariableRemover::visit(MemberAccess &memacc) void UnusedVariableRemover::visit(UnaryExpression &unary) { TraversingVisitor::visit(unary); - if(unary.oper=="++" || unary.oper=="--") - side_effects = true; + if(unary.oper->token[1]=='+' || unary.oper->token[1]=='-') + r_side_effects = true; } void UnusedVariableRemover::visit(BinaryExpression &binary) { - if(binary.oper=="[") + if(binary.oper->token[0]=='[') { if(assignment_target) - assign_to_subscript = true; + r_assign_to_subfield = true; binary.left->visit(*this); - SetForScope set(assignment_target, false); + SetFlag set(assignment_target, false); binary.right->visit(*this); } else @@ -462,24 +776,27 @@ void UnusedVariableRemover::visit(BinaryExpression &binary) void UnusedVariableRemover::visit(Assignment &assign) { { - assign_to_subscript = false; - SetForScope set(assignment_target, !assign.self_referencing); + SetFlag set(assignment_target, !assign.self_referencing); assign.left->visit(*this); } assign.right->visit(*this); - assignment = &assign; - side_effects = true; + r_assignment = &assign; + r_side_effects = true; } void UnusedVariableRemover::visit(FunctionCall &call) { TraversingVisitor::visit(call); - side_effects = true; + /* Treat function calls as having side effects so expression statements + consisting of nothing but a function call won't be optimized away. */ + r_side_effects = true; } void UnusedVariableRemover::record_assignment(VariableDeclaration &var, Node &node, bool chained) { VariableInfo &var_info = variables.back()[&var]; + /* An assignment which completely replaces the value of the variable causes + any previous unreferenced assignments to be unused. */ if(!chained) clear_assignments(var_info, true); var_info.assignments.push_back(&node); @@ -498,19 +815,19 @@ void UnusedVariableRemover::clear_assignments(VariableInfo &var_info, bool mark_ void UnusedVariableRemover::visit(ExpressionStatement &expr) { - assignment = 0; - side_effects = false; + r_assignment = 0; + r_assign_to_subfield = false; + r_side_effects = false; TraversingVisitor::visit(expr); - if(assignment && assignment->target_declaration) - record_assignment(*assignment->target_declaration, expr, (assignment->self_referencing || assign_to_subscript)); - if(!side_effects) + if(r_assignment && r_assignment->target_declaration) + record_assignment(*r_assignment->target_declaration, expr, (r_assignment->self_referencing || r_assign_to_subfield)); + if(!r_side_effects) unused_nodes.insert(&expr); } void UnusedVariableRemover::visit(StructDeclaration &strct) { SetForScope set(aggregate, &strct); - unused_nodes.insert(&strct); TraversingVisitor::visit(strct); } @@ -524,7 +841,6 @@ void UnusedVariableRemover::visit(VariableDeclaration &var) if(var.init_expression) record_assignment(var, *var.init_expression, false); } - unused_nodes.erase(var.type_declaration); TraversingVisitor::visit(var); } @@ -532,7 +848,7 @@ void UnusedVariableRemover::visit(InterfaceBlock &iface) { SetForScope set(aggregate, &iface); unused_nodes.insert(&iface); - TraversingVisitor::visit(iface); + iface.struct_declaration->members.visit(*this); } void UnusedVariableRemover::visit(FunctionDeclaration &func) @@ -544,10 +860,18 @@ void UnusedVariableRemover::visit(FunctionDeclaration &func) func.body.visit(*this); BlockVariableMap &block_variables = variables.back(); + + /* Mark global variables as conditionally assigned so assignments in other + functions won't be removed. */ for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i) - i->second.conditionally_assigned = true; + if(!i->second.local) + i->second.conditionally_assigned = true; + + /* Always treat function parameters as referenced. Removing unused + parameters is not currently supported. */ for(NodeArray::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i) block_variables[i->get()].referenced = true; + merge_down_variables(); } @@ -561,7 +885,9 @@ void UnusedVariableRemover::merge_down_variables() { if(!i->second.referenced) unused_nodes.insert(i->first); - clear_assignments(i->second, i->first->interface!="out"); + /* Any unreferenced assignments when a variable runs out of scope + become unused. */ + clear_assignments(i->second, true); continue; } @@ -570,6 +896,7 @@ void UnusedVariableRemover::merge_down_variables() parent_variables.insert(*i); else { + // Merge a non-local variable's state into the parent scope. if(i->second.referenced || !i->second.conditionally_assigned) clear_assignments(j->second, !i->second.referenced); j->second.conditionally_assigned = i->second.conditionally_assigned; @@ -590,20 +917,25 @@ void UnusedVariableRemover::visit(Conditional &cond) swap(variables.back(), if_variables); cond.else_body.visit(*this); + // Combine variables from both branches. BlockVariableMap &else_variables = variables.back(); for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i) { BlockVariableMap::iterator j = if_variables.find(i->first); if(j!=if_variables.end()) { + // The variable was found in both branches. i->second.assignments.insert(i->second.assignments.end(), j->second.assignments.begin(), j->second.assignments.end()); i->second.conditionally_assigned |= j->second.conditionally_assigned; if_variables.erase(j); } else + // Mark variables found in only one branch as conditionally assigned. i->second.conditionally_assigned = true; } + /* Move variables which were only used in the if block into the combined + block. */ for(BlockVariableMap::iterator i=if_variables.begin(); i!=if_variables.end(); ++i) { i->second.conditionally_assigned = true; @@ -617,12 +949,6 @@ void UnusedVariableRemover::visit(Iteration &iter) { variables.push_back(BlockVariableMap()); TraversingVisitor::visit(iter); - - BlockVariableMap &block_variables = variables.back(); - for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i) - if(!i->second.local && i->second.referenced) - clear_assignments(i->second, false); - merge_down_variables(); }