dependency_graph.hpp

 
#pragma once
 
#include <nk/core/ast.hpp>
#include <nk/core/elem_regions.hpp>
 
#include <set>
#include <string>
#include <vector>
 
namespace nk {

inline constexpr char kFigureStateVar[] = "__nk_figstate__";
 
struct StatementFacts
{
    bool wildcardReads = false;      // Reads = * (opaque statement)
    std::set<std::string> reads;
    std::set<std::string> writes;
 
    // Fine-grained element access (portion B1): variable → regions
    // touched on the READ side / WRITE side. All accesses that are not
    // statically literal collapse to VarRegions::all (conservative).
    // Coarse `reads`/`writes` stay authoritative; the maps refine them.
    ElemAccessMap elemReads;
    ElemAccessMap elemWrites;
 
    // Variables whose coarse `reads` entry came ONLY from a merge-write
    // LHS (`C{5,2} = v` — the LHS does NOT read the old value; the
    // coarse read exists for portion-A dirtySetFor compatibility).
    // Element-level dirty sets use this to skip cell definitions.
    std::set<std::string> lhsMergeBases;
};

std::vector<StatementFacts> computeStatementFacts(const ASTNode *program);

class DependencyGraph
{
public:
    explicit DependencyGraph(std::vector<StatementFacts> facts);

    std::vector<size_t> dirtySetFor(const std::string &var) const;

    std::vector<size_t> dirtySetFor(
        const std::string &var,
        const std::set<std::string> &externalDefs) const;

    std::vector<size_t> dirtySetForElement(const std::string &var,
                                           size_t r, size_t c) const;
    std::vector<size_t> dirtySetForElement(
        const std::string &var, size_t r, size_t c,
        const std::set<std::string> &externalDefs) const;
 
    const std::vector<StatementFacts> &facts() const { return facts_; }
    size_t size() const { return facts_.size(); }
    const std::vector<size_t> &downstreamOf(size_t i) const
    {
        return downstream_[i];
    }
 
private:
    std::vector<StatementFacts> facts_;
    std::vector<std::vector<size_t>> downstream_;   // i → dependents
};
 
}  // namespace nk