From: protonspring <mike@whiteley.org>
Date: Thu, 26 Mar 2020 01:57:36 +0000 (-0600)
Subject: Limit array access in Position
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=0b8ce4b3037c0efcb2c8bf10598ec3f4fd919e1a

Limit array access in Position

This is a non-functional code style change that routes all position array accesses to single methods, and adds an assert to check correctness.

Passed STC
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 37312 W: 7378 L: 7246 D: 22688
Ptnml(0-2): 606, 4280, 8762, 4392, 616
https://tests.stockfishchess.org/tests/view/5e7c0c69e42a5c3b3ca2eb3d

closes https://github.com/official-stockfish/Stockfish/pull/2595

No functional change.
---

diff --git a/src/position.h b/src/position.h
index e5071d53..f79c5463 100644
--- a/src/position.h
+++ b/src/position.h
@@ -83,7 +83,6 @@ public:
   const std::string fen() const;
 
   // Position representation
-  Bitboard pieces() const;
   Bitboard pieces(PieceType pt) const;
   Bitboard pieces(PieceType pt1, PieceType pt2) const;
   Bitboard pieces(Color c) const;
@@ -207,28 +206,25 @@ inline Color Position::side_to_move() const {
   return sideToMove;
 }
 
-inline bool Position::empty(Square s) const {
-  return board[s] == NO_PIECE;
-}
-
 inline Piece Position::piece_on(Square s) const {
+  assert(is_ok(s));
   return board[s];
 }
 
-inline Piece Position::moved_piece(Move m) const {
-  return board[from_sq(m)];
+inline bool Position::empty(Square s) const {
+  return piece_on(s) == NO_PIECE;
 }
 
-inline Bitboard Position::pieces() const {
-  return byTypeBB[ALL_PIECES];
+inline Piece Position::moved_piece(Move m) const {
+  return piece_on(from_sq(m));
 }
 
-inline Bitboard Position::pieces(PieceType pt) const {
+inline Bitboard Position::pieces(PieceType pt = ALL_PIECES) const {
   return byTypeBB[pt];
 }
 
 inline Bitboard Position::pieces(PieceType pt1, PieceType pt2) const {
-  return byTypeBB[pt1] | byTypeBB[pt2];
+  return pieces(pt1) | pieces(pt2);
 }
 
 inline Bitboard Position::pieces(Color c) const {
@@ -236,11 +232,11 @@ inline Bitboard Position::pieces(Color c) const {
 }
 
 inline Bitboard Position::pieces(Color c, PieceType pt) const {
-  return byColorBB[c] & byTypeBB[pt];
+  return pieces(c) & pieces(pt);
 }
 
 inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const {
-  return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]);
+  return pieces(c) & (pieces(pt1) | pieces(pt2));
 }
 
 template<PieceType Pt> inline int Position::count(Color c) const {
@@ -248,7 +244,7 @@ template<PieceType Pt> inline int Position::count(Color c) const {
 }
 
 template<PieceType Pt> inline int Position::count() const {
-  return pieceCount[make_piece(WHITE, Pt)] + pieceCount[make_piece(BLACK, Pt)];
+  return count<Pt>(WHITE) + count<Pt>(BLACK);
 }
 
 template<PieceType Pt> inline const Square* Position::squares(Color c) const {
@@ -257,7 +253,7 @@ template<PieceType Pt> inline const Square* Position::squares(Color c) const {
 
 template<PieceType Pt> inline Square Position::square(Color c) const {
   assert(pieceCount[make_piece(c, Pt)] == 1);
-  return pieceList[make_piece(c, Pt)][0];
+  return squares<Pt>(c)[0];
 }
 
 inline Square Position::ep_square() const {
@@ -279,7 +275,7 @@ inline int Position::castling_rights(Color c) const {
 inline bool Position::castling_impeded(CastlingRights cr) const {
   assert(cr == WHITE_OO || cr == WHITE_OOO || cr == BLACK_OO || cr == BLACK_OOO);
 
-  return byTypeBB[ALL_PIECES] & castlingPath[cr];
+  return pieces() & castlingPath[cr];
 }
 
 inline Square Position::castling_rook_square(CastlingRights cr) const {
@@ -292,7 +288,7 @@ template<PieceType Pt>
 inline Bitboard Position::attacks_from(Square s) const {
   static_assert(Pt != PAWN, "Pawn attacks need color");
 
-  return  Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, byTypeBB[ALL_PIECES])
+  return  Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, pieces())
         : Pt == QUEEN  ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
         : PseudoAttacks[Pt][s];
 }
@@ -303,11 +299,11 @@ inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
 }
 
 inline Bitboard Position::attacks_from(PieceType pt, Square s) const {
-  return attacks_bb(pt, s, byTypeBB[ALL_PIECES]);
+  return attacks_bb(pt, s, pieces());
 }
 
 inline Bitboard Position::attackers_to(Square s) const {
-  return attackers_to(s, byTypeBB[ALL_PIECES]);
+  return attackers_to(s, pieces());
 }
 
 inline Bitboard Position::checkers() const {
@@ -360,7 +356,7 @@ inline Value Position::non_pawn_material(Color c) const {
 }
 
 inline Value Position::non_pawn_material() const {
-  return st->nonPawnMaterial[WHITE] + st->nonPawnMaterial[BLACK];
+  return non_pawn_material(WHITE) + non_pawn_material(BLACK);
 }
 
 inline int Position::game_ply() const {
@@ -372,8 +368,8 @@ inline int Position::rule50_count() const {
 }
 
 inline bool Position::opposite_bishops() const {
-  return   pieceCount[W_BISHOP] == 1
-        && pieceCount[B_BISHOP] == 1
+  return   count<BISHOP>(WHITE) == 1
+        && count<BISHOP>(BLACK) == 1
         && opposite_colors(square<BISHOP>(WHITE), square<BISHOP>(BLACK));
 }