ld_ir.h

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#pragma once
 
#include <ld-frontend/parser/ld_ast.h>
#include <ld-frontend/semantics/sos_semantics.h>
#include <string>
#include <vector>
 
// -----------------------------------------------------------------------
// LdIR — cyclic control-flow graph over SOS state-transition blocks.
//
// Structure:
//   INIT_BLOCK
//   └── SCAN_LOOP (while true)
//       ├── READ_INPUTS
//       ├── RUNG_1 ... RUNG_n
//       └── WRITE_OUTPUTS
// -----------------------------------------------------------------------
 
enum class LdIRNodeKind
{
  ContactEval, // evaluate a contact → produces power-flow value
  CoilAssign,  // assign coil output
  TimerStep,   // TON/TOF/TP fixed-tick step
  CounterStep, // CTU/CTD per-scan step
  ArithStep,   // arithmetic FB step
};
 
// One IR instruction corresponding to a single SOS rule application.
struct LdIRNode
{
  LdIRNodeKind kind;
  SosRule rule; // which SOS rule generated this node
 
  // Fields used by ContactEval / CoilAssign
  std::string variable;
  ContactKind contact_kind = ContactKind::NormallyOpen;
  ContactEdge contact_edge = ContactEdge::None;
  CoilKind coil_kind = CoilKind::Output;
 
  // Fields used by TimerStep
  std::string timer_instance; // FB instance name (for shadow edge variable)
  std::string timer_IN;
  std::string timer_ET;
  std::string timer_PT;
  std::string timer_Q;
  FBKind timer_kind = FBKind::TON;
 
  // Fields used by CounterStep
  std::string ctr_instance; // FB instance name (for shadow edge variable)
  std::string ctr_CU;
  std::string ctr_CD;
  std::string ctr_R;
  std::string ctr_LD;
  std::string ctr_CV;
  std::string ctr_PV;
  std::string ctr_Q;
  FBKind ctr_kind = FBKind::CTU;
 
  // Fields used by ArithStep
  std::string arith_IN1;
  std::string arith_IN2;
  std::string arith_OUT;
  FBKind arith_kind = FBKind::ADD;
 
  LdLocation loc;
};
 
// A rung block is a sequence of IR nodes evaluated in order within one scan.
struct LdIRRung
{
  std::string id;
  std::vector<LdIRNode> nodes;
  LdLocation loc;
};
 
// A user-defined FB instance to execute once per scan cycle, with its ST body.
struct UserFBExec
{
  std::string type_name;
  std::string instance_name;
  std::vector<FBVarDecl> input_vars;  // formal inputs (IN1, IN2, ...) + types
  std::vector<FBVarDecl> local_vars;  // FB locals (e.g. "i") + types
  std::vector<FBVarDecl> output_vars; // every formal output + types
  std::vector<FBInWire> in_wires;     // input pin sources ("" => nondet)
  std::vector<FBOutWire> out_wires;   // FB pin -> program variable assignments
  std::string st_body;                // raw Structured Text
};
 
// Top-level IR: variable declarations + the ordered list of rungs.
struct LdIR
{
  std::string source_file;
  std::vector<VarDecl> variables;   // copied from LdAst
  std::vector<LdIRRung> rungs;      // ordered scan body
  std::vector<UserFBExec> user_fbs; // user-defined FB bodies to execute
};