structured_sdfg_walker.h

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#pragma once
 
#include "sdfg/structured_control_flow/control_flow_node.h"
#include "sdfg/visitor/structured_sdfg_visitor.h"
 
namespace sdfg::visitor {

class StructuredSDFGWalker {
public:
    enum class Scope { NONE, ENTRY, EXIT, IF_ENTRY, IF_EXIT, IF_NEXT_BRANCH };
 
    static constexpr std::string_view scope_to_string(Scope scope) {
        switch (scope) {
            case Scope::NONE:
                return "NONE";
            case Scope::ENTRY:
                return "ENTRY";
            case Scope::EXIT:
                return "EXIT";
            case Scope::IF_ENTRY:
                return "IF_ENTRY";
            case Scope::IF_EXIT:
                return "IF_EXIT";
            case Scope::IF_NEXT_BRANCH:
                return "IF_NEXT_BRANCH";
        }
        return "UNKNOWN";
    }
 
    class Iterator;
 
    class ParentScopeLoc {
        friend StructuredSDFGWalker;
        friend Iterator;
 
        ControlFlowNode* node_;
        int32_t idx_;
        ParentScopeLoc(ControlFlowNode* node, int32_t idx) : node_(node), idx_(idx) {
        }
    };
 
    class Iterator {
        friend StructuredSDFGWalker;
 
    private:
        ControlFlowNode* node_;
        int32_t idx_;
        std::list<ParentScopeLoc> parent_cache_;
 
        Iterator(ControlFlowNode* node, int32_t idx);
 
        Iterator& next_internal(bool descend);
 
        void move_to_parent_next(ControlFlowNode* child, bool descend);
 
        //
        void move_to_next_child(ControlFlowNode* parent, int32_t prev_idx, bool descend, ParentScopeLoc* parent_cache);
        void move_to_next_seq_child(Sequence* parent, int32_t prev_idx, bool descend, ParentScopeLoc* parent_cache);
        void move_to_next_ifelse_child(IfElse* parent, int32_t prev_idx, bool descend, ParentScopeLoc* parent_cache);
        void move_to_next_loop_child(ControlFlowNode* parent, ParentScopeLoc* parent_cache);
 
        void set_enter_node_idx(ControlFlowNode& child, bool descend);
 
    public:
        bool operator!=(const Iterator& other) const;
        Iterator& operator++();

        Iterator& next();

        Iterator& next_no_descend();
        std::pair<ControlFlowNode&, Scope> operator*() const;
    };
 
private:
    static constexpr int32_t NO_SCOPE_FLAG = 0x80000000;
    static constexpr int32_t SCOPE_MASK = 0x8000007F;
    static constexpr int32_t SCOPE_ANY_MASK = 0x70;
    static constexpr int32_t SCOPE_ENTRY_FLAG = 0x00000001;
    static constexpr int32_t SCOPE_EXIT_FLAG = 0x00000002;
    static constexpr int32_t SEQ_FLAG = 0x80000010;
    static constexpr int32_t SEQ_MASK = 0x8000001F;
    static constexpr int32_t SEQ_ENTER = SEQ_FLAG | SCOPE_ENTRY_FLAG;
    static constexpr int32_t SEQ_EXIT = SEQ_FLAG | SCOPE_EXIT_FLAG;
    static constexpr int32_t LOOP_FLAG = 0x80000020;
    static constexpr int32_t LOOP_MASK = 0x8000002F;
    static constexpr int32_t LOOP_ENTER = LOOP_FLAG | SCOPE_ENTRY_FLAG;
    static constexpr int32_t LOOP_EXIT = LOOP_FLAG | SCOPE_EXIT_FLAG;
    static constexpr int32_t IFELSE_FLAG = 0x80000040;
    static constexpr int32_t IFELSE_MASK = 0x8000004F;
    static constexpr int32_t IFELSE_ENTER = IFELSE_FLAG | SCOPE_ENTRY_FLAG;
    static constexpr int32_t IFELSE_EXIT = IFELSE_FLAG | SCOPE_EXIT_FLAG;
 
public:
    static Iterator root(StructuredSDFG& sdfg);
    static Iterator from_node(ControlFlowNode& node);
    static Iterator sequence_exit(Sequence& seq);
    static Iterator ifelse_exit(IfElse& ifelse);
    static Iterator loop_exit(While& loop);
    static Iterator loop_exit(StructuredLoop& loop);
    static Iterator end();
 
    static Iterator from_after(ControlFlowNode& node);
 
protected:
};
 
inline std::ostream& operator<<(std::ostream& os, StructuredSDFGWalker::Scope scope) {
    os << StructuredSDFGWalker::scope_to_string(scope);
    return os;
}
 
} // namespace sdfg::visitor