utils/TableGen/InstrSelectorEmitter.h

//===- InstrInfoEmitter.h - Generate a Instruction Set Desc. ----*- C++ -*-===//
//
// This tablegen backend is responsible for emitting a description of the target
// instruction set for the code generator.
//
//===----------------------------------------------------------------------===//

#ifndef INSTRSELECTOR_EMITTER_H
#define INSTRSELECTOR_EMITTER_H

#include "TableGenBackend.h"
#include "CodeGenWrappers.h"
#include <vector>
#include <map>
class DagInit;
class Init;
class InstrSelectorEmitter;

/// NodeType - Represents Information parsed from the DagNode entries.
///
struct NodeType {
  enum ArgResultTypes {
    // Both argument and return types...
    Val,            // A non-void type
    Arg0,           // Value matches the type of Arg0
    Ptr,            // Tree node is the type of the target pointer

    // Return types
    Void,           // Tree node always returns void
  };

  ArgResultTypes ResultType;
  std::vector<ArgResultTypes> ArgTypes;

  NodeType(ArgResultTypes RT, std::vector<ArgResultTypes> &AT) : ResultType(RT){
    AT.swap(ArgTypes);
  }

  NodeType() : ResultType(Val) {}
  NodeType(const NodeType &N) : ResultType(N.ResultType), ArgTypes(N.ArgTypes){}

  static ArgResultTypes Translate(Record *R);
};



/// TreePatternNode - Represent a node of the tree patterns.
///
class TreePatternNode {
  /// Operator - The operation that this node represents... this is null if this
  /// is a leaf.
  Record *Operator;

  /// Type - The inferred value type...
  ///
  MVT::ValueType                Type;

  /// Children - If this is not a leaf (Operator != 0), this is the subtrees
  /// that we contain.
  std::vector<TreePatternNode*> Children;

  /// Value - If this node is a leaf, this indicates what the thing is.
  ///
  Init *Value;
public:
  TreePatternNode(Record *o, const std::vector<TreePatternNode*> &c)
    : Operator(o), Type(MVT::Other), Children(c), Value(0) {}
  TreePatternNode(Init *V) : Operator(0), Type(MVT::Other), Value(V) {}

  Record *getOperator() const { return Operator; }
  MVT::ValueType getType() const { return Type; }
  void setType(MVT::ValueType T) { Type = T; }

  bool isLeaf() const { return Operator == 0; }

  const std::vector<TreePatternNode*> &getChildren() const {
    assert(Operator != 0 && "This is a leaf node!");
    return Children;
  }
  TreePatternNode *getChild(unsigned c) const {
    assert(c < Children.size() && "Child access out of range!");
    return getChildren()[c];
  }

  Init *getValue() const {
    assert(Operator == 0 && "This is not a leaf node!");
    return Value;
  }

  void dump() const;


  // UpdateNodeType - Set the node type of N to VT if VT contains information.
  // If N already contains a conflicting type, then throw an exception.  This
  // returns true if any information was updated.
  //
  bool updateNodeType(MVT::ValueType VT, const std::string &RecName);
};

std::ostream &operator<<(std::ostream &OS, const TreePatternNode &N);



/// Pattern - Represent a pattern of one form or another.  Currently, three
/// types of patterns are possible: Instruction's, Nonterminals, and Expanders.
///
struct Pattern {
  enum PatternType {
    Nonterminal, Instruction, Expander
  };
private:
  /// PTy - The type of pattern this is.
  ///
  PatternType PTy;

  /// Tree - The tree pattern which corresponds to this pattern.  Note that if
  /// there was a (set) node on the outside level that it has been stripped off.
  ///
  TreePatternNode *Tree;
  
  /// Result - If this is an instruction or expander pattern, this is the
  /// register result, specified with a (set) in the pattern.
  ///
  Record *Result;

  /// TheRecord - The actual TableGen record corresponding to this pattern.
  ///
  Record *TheRecord;

  /// Resolved - This is true of the pattern is useful in practice.  In
  /// particular, some non-terminals will have non-resolvable types.  When a
  /// user of the non-terminal is later found, they will have inferred a type
  /// for the result of the non-terminal, which cause a clone of an unresolved
  /// nonterminal to be made which is "resolved".
  ///
  bool Resolved;

  /// ISE - the instruction selector emitter coordinating this madness.
  ///
  InstrSelectorEmitter &ISE;
public:

  /// Pattern constructor - Parse the specified DagInitializer into the current
  /// record.
  Pattern(PatternType pty, DagInit *RawPat, Record *TheRec,
          InstrSelectorEmitter &ise);

  /// getPatternType - Return what flavor of Record this pattern originated from
  ///
  PatternType getPatternType() const { return PTy; }

  /// getTree - Return the tree pattern which corresponds to this pattern.
  ///
  TreePatternNode *getTree() const { return Tree; }
  
  Record *getResult() const { return Result; }

  /// getRecord - Return the actual TableGen record corresponding to this
  /// pattern.
  ///
  Record *getRecord() const { return TheRecord; }

  bool isResolved() const { return Resolved; }

private:
  TreePatternNode *ParseTreePattern(DagInit *DI);
  bool InferTypes(TreePatternNode *N, bool &MadeChange);
  void error(const std::string &Msg);
};

std::ostream &operator<<(std::ostream &OS, const Pattern &P);



/// InstrSelectorEmitter - The top-level class which coordinates construction
/// and emission of the instruction selector.
///
class InstrSelectorEmitter : public TableGenBackend {
  RecordKeeper &Records;
  CodeGenTarget Target;

  std::map<Record*, NodeType> NodeTypes;

  /// Patterns - a list of all of the patterns defined by the target description
  ///
  std::map<Record*, Pattern*> Patterns;
public:
  InstrSelectorEmitter(RecordKeeper &R) : Records(R) {}
  
  // run - Output the instruction set description, returning true on failure.
  void run(std::ostream &OS);

  const CodeGenTarget &getTarget() const { return Target; }
  std::map<Record*, NodeType> &getNodeTypes() { return NodeTypes; }

private:
  // ReadNodeTypes - Read in all of the node types in the current RecordKeeper,
  // turning them into the more accessible NodeTypes data structure.
  void ReadNodeTypes();

  // ReadNonTerminals - Read in all nonterminals and incorporate them into our
  // pattern database.
  void ReadNonterminals();

  // ReadInstructionPatterns - Read in all subclasses of Instruction, and
  // process those with a useful Pattern field.
  void ReadInstructionPatterns();

  // ReadExpanderPatterns - Read in all of the expanded patterns.
  void ReadExpanderPatterns();

  // InstantiateNonterminals - Instantiate any unresolved nonterminals with
  // information from the context that they are used in.
  void InstantiateNonterminals();
};

#endif