return r_result_name;
}
-string InlineContentInjector::create_unused_name(const string &base, bool always_prefix)
-{
- string result = base;
- if(always_prefix || target_block->variables.count(result))
- result = format("_%s_%s", source_func->name, base);
- unsigned initial_size = result.size();
- for(unsigned i=1; target_block->variables.count(result); ++i)
- {
- result.erase(initial_size);
- result += format("_%d", i);
- }
- return result;
-}
-
void InlineContentInjector::visit(VariableReference &var)
{
if(remap_names)
if(!remap_names && !deps_only)
{
RefPtr<VariableDeclaration> inlined_var = var.clone();
- inlined_var->name = create_unused_name(var.name, false);
+ inlined_var->name = get_unused_variable_name(*target_block, var.name, source_func->name);
r_inlined_statement = inlined_var;
variable_map[var.name] = inlined_var.get();
{
/* Create a new variable to hold the return value of the inlined
function. */
- r_result_name = create_unused_name("return", true);
+ r_result_name = get_unused_variable_name(*target_block, "_return", source_func->name);
RefPtr<VariableDeclaration> var = new VariableDeclaration;
var->source = ret.source;
var->line = ret.line;
return r_any_inlined;
}
-void FunctionInliner::visit_and_inline(RefPtr<Expression> &ptr)
+void FunctionInliner::visit(RefPtr<Expression> &ptr)
{
r_inline_result = 0;
ptr->visit(*this);
}
}
-void FunctionInliner::visit(UnaryExpression &unary)
-{
- visit_and_inline(unary.expression);
-}
-
-void FunctionInliner::visit(BinaryExpression &binary)
-{
- visit_and_inline(binary.left);
- visit_and_inline(binary.right);
-}
-
-void FunctionInliner::visit(MemberAccess &memacc)
-{
- visit_and_inline(memacc.left);
-}
-
-void FunctionInliner::visit(Swizzle &swizzle)
-{
- visit_and_inline(swizzle.left);
-}
-
void FunctionInliner::visit(FunctionCall &call)
{
for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
- visit_and_inline(*i);
+ visit(*i);
FunctionDeclaration *def = call.declaration;
if(def)
}
}
-void FunctionInliner::visit(ExpressionStatement &expr)
-{
- visit_and_inline(expr.expression);
-}
-
-void FunctionInliner::visit(VariableDeclaration &var)
-{
- if(var.init_expression)
- visit_and_inline(var.init_expression);
-}
-
void FunctionInliner::visit(FunctionDeclaration &func)
{
SetForScope<FunctionDeclaration *> set_func(current_function, &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
iter.body.visit(*this);
}
-void FunctionInliner::visit(Return &ret)
-{
- if(ret.expression)
- visit_and_inline(ret.expression);
-}
-
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)
{ }
return r_any_inlined;
}
-void ExpressionInliner::visit_and_record(RefPtr<Expression> &ptr, const Operator *outer_oper, bool on_rhs)
+void ExpressionInliner::inline_expression(Expression &expr, RefPtr<Expression> &ptr)
+{
+ ptr = expr.clone();
+ r_any_inlined = true;
+}
+
+void ExpressionInliner::visit(Block &block)
+{
+ TraversingVisitor::visit(block);
+
+ for(map<string, VariableDeclaration *>::iterator i=block.variables.begin(); i!=block.variables.end(); ++i)
+ {
+ map<Assignment::Target, ExpressionInfo>::iterator j = expressions.lower_bound(i->second);
+ for(; (j!=expressions.end() && j->first.declaration==i->second); )
+ {
+ if(j->second.expression && j->second.inline_point)
+ inline_expression(*j->second.expression, *j->second.inline_point);
+
+ expressions.erase(j++);
+ }
+ }
+
+ /* Expressions assigned in this block may depend on local variables of the
+ block. If this is a conditionally executed block, the assignments might not
+ always happen. Mark the expressions as not available to any outer blocks. */
+ for(map<Assignment::Target, ExpressionInfo>::iterator i=expressions.begin(); i!=expressions.end(); ++i)
+ if(i->second.assign_scope==&block)
+ i->second.available = false;
+}
+
+void ExpressionInliner::visit(RefPtr<Expression> &expr)
{
r_ref_info = 0;
- ptr->visit(*this);
+ expr->visit(*this);
if(r_ref_info && r_ref_info->expression && r_ref_info->available)
{
if(iteration_body && !r_ref_info->trivial)
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);
+ inline_expression(*r_ref_info->expression, expr);
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->inline_point = &expr;
}
+ r_oper = expr->oper;
r_ref_info = 0;
}
-void ExpressionInliner::inline_expression(Expression &expr, RefPtr<Expression> &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<ParenthesizedExpression> 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<VariableDeclaration *, ExpressionInfo>::iterator i=expressions.begin(); i!=expressions.end(); )
- {
- map<string, VariableDeclaration *>::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;
- }
- }
-}
-
void ExpressionInliner::visit(VariableReference &var)
{
if(var.declaration)
{
- map<VariableDeclaration *, ExpressionInfo>::iterator i = expressions.find(var.declaration);
+ map<Assignment::Target, ExpressionInfo>::iterator i = expressions.find(var.declaration);
if(i!=expressions.end())
{
/* If a non-trivial expression is referenced multiple times, don't
void ExpressionInliner::visit(MemberAccess &memacc)
{
- visit_and_record(memacc.left, memacc.oper, false);
- r_oper = memacc.oper;
+ visit(memacc.left);
r_trivial = false;
}
void ExpressionInliner::visit(Swizzle &swizzle)
{
- visit_and_record(swizzle.left, swizzle.oper, false);
- r_oper = swizzle.oper;
+ visit(swizzle.left);
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;
+ visit(unary.expression);
r_trivial = false;
}
void ExpressionInliner::visit(BinaryExpression &binary)
{
- visit_and_record(binary.left, binary.oper, false);
+ visit(binary.left);
{
SetFlag clear_target(mutating, false);
- visit_and_record(binary.right, binary.oper, true);
+ visit(binary.right);
}
- r_oper = binary.oper;
r_trivial = false;
}
{
{
SetFlag set_target(mutating);
- visit_and_record(assign.left, assign.oper, false);
+ visit(assign.left);
}
r_oper = 0;
- visit_and_record(assign.right, assign.oper, true);
+ visit(assign.right);
- if(VariableDeclaration *target_var = dynamic_cast<VariableDeclaration *>(assign.target.declaration))
+ map<Assignment::Target, ExpressionInfo>::iterator i = expressions.find(assign.target);
+ if(i!=expressions.end())
{
- map<VariableDeclaration *, ExpressionInfo>::iterator i = expressions.find(target_var);
- 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;
- }
+ /* 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.available = true;
}
- r_oper = assign.oper;
+ r_trivial = false;
+}
+
+void ExpressionInliner::visit(TernaryExpression &ternary)
+{
+ visit(ternary.condition);
+ visit(ternary.true_expr);
+ visit(ternary.false_expr);
r_trivial = false;
}
void ExpressionInliner::visit(FunctionCall &call)
{
- for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
- visit_and_record(*i, 0, false);
- r_oper = 0;
+ TraversingVisitor::visit(call);
r_trivial = false;
}
{
r_oper = 0;
r_trivial = true;
- if(var.init_expression)
- visit_and_record(var.init_expression, 0, false);
+ TraversingVisitor::visit(var);
bool constant = var.constant;
if(constant && var.layout)
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<Block *> set_block(current_block, &iter.body);
SetForScope<Block *> set_body(iteration_body, &iter.body);
if(iter.condition)
- iter.condition->visit(*this);
+ visit(iter.condition);
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);
+ visit(iter.loop_expression);
}
void ConstantConditionEliminator::visit(Conditional &cond)
{
- ExpressionEvaluator eval;
- 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;
- }
+ if(Literal *literal = dynamic_cast<Literal *>(cond.condition.get()))
+ if(literal->value.check_type<bool>())
+ {
+ Block &block = (literal->value.value<bool>() ? cond.body : cond.else_body);
+ current_block->body.splice(insert_point, block.body);
+ nodes_to_remove.insert(&cond);
+ return;
+ }
TraversingVisitor::visit(cond);
}
}
-UnusedVariableRemover::VariableInfo::VariableInfo():
- local(false),
- conditionally_assigned(false),
- referenced(false)
-{ }
-
-
bool UnusedTypeRemover::apply(Stage &stage)
{
stage.content.visit(*this);
TraversingVisitor::visit(binary);
}
+void UnusedTypeRemover::visit(TernaryExpression &ternary)
+{
+ unused_nodes.erase(ternary.type);
+ TraversingVisitor::visit(ternary);
+}
+
void UnusedTypeRemover::visit(FunctionCall &call)
{
unused_nodes.erase(call.type);
UnusedVariableRemover::UnusedVariableRemover():
- aggregate(0),
+ stage(0),
+ interface_block(0),
r_assignment(0),
assignment_target(false),
- r_assign_to_subfield(false),
r_side_effects(false)
{ }
-bool UnusedVariableRemover::apply(Stage &stage)
+bool UnusedVariableRemover::apply(Stage &s)
{
- variables.push_back(BlockVariableMap());
- stage.content.visit(*this);
- BlockVariableMap &global_variables = variables.back();
- for(BlockVariableMap::iterator i=global_variables.begin(); i!=global_variables.end(); ++i)
- {
- string interface = i->first->interface;
- bool linked = i->first->linked_declaration;
- map<VariableDeclaration *, Node *>::iterator j = aggregates.find(i->first);
- if(j!=aggregates.end())
- if(InterfaceBlock *iface = dynamic_cast<InterfaceBlock *>(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)
+ stage = &s;
+ s.content.visit(*this);
+
+ for(list<AssignmentInfo>::const_iterator i=assignments.begin(); i!=assignments.end(); ++i)
+ if(i->used_by.empty())
+ unused_nodes.insert(i->node);
+
+ for(map<string, InterfaceBlock *>::const_iterator i=s.interface_blocks.begin(); i!=s.interface_blocks.end(); ++i)
+ if(i->second->instance_name.empty())
+ unused_nodes.insert(i->second);
+
+ for(BlockVariableMap::const_iterator i=variables.begin(); i!=variables.end(); ++i)
+ {
+ if(i->second.output)
{
- unused_nodes.insert(i->first);
- clear_assignments(i->second, true);
+ /* The last visible assignments of output variables are used by the
+ next stage or the API. */
+ for(vector<AssignmentInfo *>::const_iterator j=i->second.assignments.begin(); j!=i->second.assignments.end(); ++j)
+ unused_nodes.erase((*j)->node);
}
+
+ if(!i->second.output && !i->second.referenced)
+ {
+ // Don't remove variables from inside interface blocks.
+ if(!i->second.interface_block)
+ unused_nodes.insert(i->first);
+ }
+ else if(i->second.interface_block)
+ // Interface blocks are kept if even one member is used.
+ unused_nodes.erase(i->second.interface_block);
}
- variables.pop_back();
- NodeRemover().apply(stage, unused_nodes);
+ NodeRemover().apply(s, unused_nodes);
return !unused_nodes.empty();
}
-void UnusedVariableRemover::visit(VariableReference &var)
+void UnusedVariableRemover::referenced(const Assignment::Target &target, Node &node)
{
- map<VariableDeclaration *, Node *>::iterator i = aggregates.find(var.declaration);
- if(i!=aggregates.end())
- unused_nodes.erase(i->second);
-
- if(var.declaration && !assignment_target)
+ VariableInfo &var_info = variables[target.declaration];
+ var_info.referenced = true;
+ if(!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;
+ for(vector<AssignmentInfo *>::const_iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
+ (*i)->used_by.push_back(&node);
}
}
-void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
-{
- unused_nodes.erase(iface.declaration);
-}
-
-void UnusedVariableRemover::visit(MemberAccess &memacc)
+void UnusedVariableRemover::visit(VariableReference &var)
{
- if(assignment_target)
- r_assign_to_subfield = true;
- TraversingVisitor::visit(memacc);
- unused_nodes.erase(memacc.declaration);
+ referenced(var.declaration, var);
}
-void UnusedVariableRemover::visit(Swizzle &swizzle)
+void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
{
- if(assignment_target)
- r_assign_to_subfield = true;
- TraversingVisitor::visit(swizzle);
+ referenced(iface.declaration, iface);
}
void UnusedVariableRemover::visit(UnaryExpression &unary)
{
if(binary.oper->token[0]=='[')
{
- if(assignment_target)
- r_assign_to_subfield = true;
binary.left->visit(*this);
SetFlag set(assignment_target, false);
binary.right->visit(*this);
void UnusedVariableRemover::visit(Assignment &assign)
{
{
- SetFlag set(assignment_target, !assign.self_referencing);
+ SetFlag set(assignment_target, (assign.oper->token[0]=='='));
assign.left->visit(*this);
}
assign.right->visit(*this);
/* 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);
- var_info.conditionally_assigned = false;
+ if(stage->type==Stage::GEOMETRY && call.name=="EmitVertex")
+ {
+ for(map<Statement *, VariableInfo>::const_iterator i=variables.begin(); i!=variables.end(); ++i)
+ if(i->second.output)
+ referenced(i->first, call);
+ }
}
-void UnusedVariableRemover::clear_assignments(VariableInfo &var_info, bool mark_unused)
+void UnusedVariableRemover::record_assignment(const Assignment::Target &target, Node &node)
{
- if(mark_unused)
+ assignments.push_back(AssignmentInfo());
+ AssignmentInfo &assign_info = assignments.back();
+ assign_info.node = &node;
+ assign_info.target = target;
+
+ /* An assignment to the target hides any assignments to the same target or
+ its subfields. */
+ VariableInfo &var_info = variables[target.declaration];
+ for(unsigned i=0; i<var_info.assignments.size(); ++i)
{
- for(vector<Node *>::iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
- unused_nodes.insert(*i);
+ const Assignment::Target &t = var_info.assignments[i]->target;
+
+ bool subfield = (t.chain_len>=target.chain_len);
+ for(unsigned j=0; (subfield && j<target.chain_len); ++j)
+ subfield = (t.chain[j]==target.chain[j]);
+
+ if(subfield)
+ var_info.assignments.erase(var_info.assignments.begin()+i);
+ else
+ ++i;
}
- var_info.assignments.clear();
+
+ var_info.assignments.push_back(&assign_info);
}
void UnusedVariableRemover::visit(ExpressionStatement &expr)
{
r_assignment = 0;
- r_assign_to_subfield = false;
r_side_effects = false;
TraversingVisitor::visit(expr);
if(r_assignment && r_assignment->target.declaration)
- if(VariableDeclaration *target_var = dynamic_cast<VariableDeclaration *>(r_assignment->target.declaration))
- record_assignment(*target_var, expr, (r_assignment->self_referencing || r_assign_to_subfield));
+ record_assignment(r_assignment->target, expr);
if(!r_side_effects)
unused_nodes.insert(&expr);
}
-void UnusedVariableRemover::visit(StructDeclaration &strct)
-{
- SetForScope<Node *> set(aggregate, &strct);
- TraversingVisitor::visit(strct);
-}
-
void UnusedVariableRemover::visit(VariableDeclaration &var)
{
- if(aggregate)
- aggregates[&var] = aggregate;
+ VariableInfo &var_info = variables[&var];
+ var_info.interface_block = interface_block;
+
+ /* Mark variables as output if they're used by the next stage or the
+ graphics API. */
+ if(interface_block)
+ var_info.output = (interface_block->interface=="out" && (interface_block->linked_block || !interface_block->name.compare(0, 3, "gl_")));
else
+ var_info.output = (var.interface=="out" && (stage->type==Stage::FRAGMENT || var.linked_declaration || !var.name.compare(0, 3, "gl_")));
+
+ if(var.init_expression)
{
- variables.back()[&var].local = true;
- if(var.init_expression)
- record_assignment(var, *var.init_expression, false);
+ var_info.initialized = true;
+ record_assignment(&var, *var.init_expression);
}
TraversingVisitor::visit(var);
}
void UnusedVariableRemover::visit(InterfaceBlock &iface)
{
- SetForScope<Node *> set(aggregate, &iface);
- unused_nodes.insert(&iface);
- iface.struct_declaration->members.visit(*this);
+ if(iface.instance_name.empty())
+ {
+ SetForScope<InterfaceBlock *> set_block(interface_block, &iface);
+ iface.struct_declaration->members.visit(*this);
+ }
+ else
+ {
+ VariableInfo &var_info = variables[&iface];
+ var_info.output = (iface.interface=="out" && (iface.linked_block || !iface.name.compare(0, 3, "gl_")));
+ }
}
-void UnusedVariableRemover::visit(FunctionDeclaration &func)
+void UnusedVariableRemover::merge_variables(const BlockVariableMap &other_vars)
{
- variables.push_back(BlockVariableMap());
-
- for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
- (*i)->visit(*this);
- func.body.visit(*this);
+ for(BlockVariableMap::const_iterator i=other_vars.begin(); i!=other_vars.end(); ++i)
+ {
+ BlockVariableMap::iterator j = variables.find(i->first);
+ if(j!=variables.end())
+ {
+ /* The merged blocks started as copies of each other so any common
+ assignments must be in the beginning. */
+ unsigned k = 0;
+ for(; (k<i->second.assignments.size() && k<j->second.assignments.size()); ++k)
+ if(i->second.assignments[k]!=j->second.assignments[k])
+ break;
+
+ // Remaining assignments are unique to each block; merge them.
+ j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin()+k, i->second.assignments.end());
+ j->second.referenced |= i->second.referenced;
+ }
+ else
+ variables.insert(*i);
+ }
+}
- BlockVariableMap &block_variables = variables.back();
+void UnusedVariableRemover::visit(FunctionDeclaration &func)
+{
+ if(func.body.body.empty())
+ return;
- /* 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)
- if(!i->second.local)
- i->second.conditionally_assigned = true;
+ BlockVariableMap saved_vars = variables;
+ // Assignments from other functions should not be visible.
+ for(BlockVariableMap::iterator i=variables.begin(); i!=variables.end(); ++i)
+ i->second.assignments.resize(i->second.initialized);
+ TraversingVisitor::visit(func);
+ swap(variables, saved_vars);
+ merge_variables(saved_vars);
/* Always treat function parameters as referenced. Removing unused
parameters is not currently supported. */
for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
- block_variables[i->get()].referenced = true;
-
- merge_down_variables();
-}
-
-void UnusedVariableRemover::merge_down_variables()
-{
- BlockVariableMap &parent_variables = variables[variables.size()-2];
- BlockVariableMap &block_variables = variables.back();
- for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
{
- if(i->second.local)
- {
- if(!i->second.referenced)
- unused_nodes.insert(i->first);
- /* Any unreferenced assignments when a variable runs out of scope
- become unused. */
- clear_assignments(i->second, true);
- continue;
- }
-
- BlockVariableMap::iterator j = parent_variables.find(i->first);
- if(j==parent_variables.end())
- 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;
- j->second.referenced |= i->second.referenced;
- j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin(), i->second.assignments.end());
- }
+ BlockVariableMap::iterator j = variables.find(i->get());
+ if(j!=variables.end())
+ j->second.referenced = true;
}
- variables.pop_back();
}
void UnusedVariableRemover::visit(Conditional &cond)
{
cond.condition->visit(*this);
- variables.push_back(BlockVariableMap());
+ BlockVariableMap saved_vars = variables;
cond.body.visit(*this);
-
- BlockVariableMap if_variables;
- swap(variables.back(), if_variables);
+ swap(saved_vars, 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;
- else_variables.insert(*i);
- }
-
- merge_down_variables();
+ /* Visible assignments after the conditional is the union of those visible
+ at the end of the if and else blocks. If there was no else block, then it's
+ the union of the if block and the state before it. */
+ merge_variables(saved_vars);
}
void UnusedVariableRemover::visit(Iteration &iter)
{
- variables.push_back(BlockVariableMap());
+ BlockVariableMap saved_vars = variables;
TraversingVisitor::visit(iter);
- merge_down_variables();
+
+ /* Merge assignments from the iteration, without clearing previous state.
+ Further analysis is needed to determine which parts of the iteration body
+ are always executed, if any. */
+ merge_variables(saved_vars);
}