d827
Reputation: 79
Function leaking memory yet is freed
I am confused as to why this function is leaking memory. It is supposed to detect checkmate in a chess recreation. It uses legal_moves(), which assigns a pointer to a head of a list of legal moves (save here) and king_under_check(), which returns a boolean value. When I run it through valgrind, I am getting a definite memory leak. Am I wrong to assume that per the valgrind output this function is where the leak originates?
My function:
Bool is_checkmate(PlayerColor c) {
Move *list = (Move *)(calloc(1, sizeof(Move)));
Move *save = list;
unsigned int num = 0;
if(is_king_under_check(c) && !legal_moves(&save, c, &num)){
freeList(save);
return TRUE;
}
freeList(save);
return FALSE;
}
and I use freeList() to free the list written to in legal_moves():
void freeList(Move *head){
Move *temp;
while(head != NULL){
temp = head;
head = head->next_move;
free(temp);
}
Here is the `valgrind` output:
==447557== 111,504 bytes in 4,646 blocks are definitely lost in loss record 44 of 47
==447557== at 0x4837B65: calloc (vg_replace_malloc.c:752)
==447557== by 0x116E55: is_checkmate (moves.c:1430)
==447557== by 0x1172BF: run_mate1 (moves.c:1486)
==447557== by 0x117CBD: run_mate2 (moves.c:1599)
==447557== by 0x109C37: main (main.c:181)
Here is my (quite long) legal moves function to may narrow down the issue:
Bool legal_moves(Move **m, PlayerColor c, unsigned int *pcount) {
/* Your implementation */
Board tempBoard = CurrentBoard;
uint64_t sq;
Move *save = (Move *)(calloc(1, sizeof(Move)));
Move *link = save;
*m = save;
Move possibleMove;
/*Move *mNode = (Move *)(calloc(1, sizeof(Move)));*/
unsigned int i, shift;
for(shift = 0; shift < 64; shift++){
/*printf("move count%d\n",*pcount);*/
sq = 1;
sq = sq<<shift;
if(player[c].k & sq){
possibleMove.from = shift;
possibleMove.piece = KING;
Pos *k_moves = king_move(possibleMove, c);
unsigned int size = *(k_moves);
unsigned int *arrPtr = k_moves;
if(size > 0){
for(i = 1; i < size+1; i++){
possibleMove.to = *(arrPtr + i);
PlayerState temp = player[c];
PlayerState temp2 = player[1-c];
if(is_king_under_check(c)){
make_move(possibleMove, player[c].k, KING, c);
if(is_king_under_check(c)){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
continue;
}
}
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
make_move(possibleMove, player[c].k, KING, c);
if(is_king_under_check(c) == TRUE){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
}
else if((board_to_pos(player[BLACK].k) == NORTH_OF(board_to_pos(player[WHITE].k))) ||
(board_to_pos(player[BLACK].k) == EAST_OF(board_to_pos(player[WHITE].k))) ||
(board_to_pos(player[BLACK].k) == SOUTH_OF(board_to_pos(player[WHITE].k))) ||
(board_to_pos(player[BLACK].k) == EAST_OF(board_to_pos(player[WHITE].k))) ||
(board_to_pos(player[BLACK].k) == SW_OF(board_to_pos(player[WHITE].k))) ||
(board_to_pos(player[BLACK].k) == SE_OF(board_to_pos(player[WHITE].k))) ||
(board_to_pos(player[BLACK].k) == NE_OF(board_to_pos(player[WHITE].k))) ||
(board_to_pos(player[BLACK].k) == NW_OF(board_to_pos(player[WHITE].k)))){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
}
else if(detect_castle_move(possibleMove, c) == 1){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
if(is_castling_valid(c) == TRUE){
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = KING;
mNode->promotion_choice = UNKNOWN;
mNode->next_move = NULL;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
/*free(mNode);*/
}
}
else{
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = KING;
mNode->promotion_choice = UNKNOWN;
mNode->next_move = NULL;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
/*free(mNode);*/
}
}
free(k_moves);
}
}
if(player[c].b & sq){
possibleMove.from = shift;
possibleMove.piece = BISHOP;
Pos *b_moves = bishop_move(possibleMove, c);
unsigned int size = *(b_moves);
unsigned int *arrPtr = b_moves;
if(size > 0){
for(i = 1; i < size+1; i++){
possibleMove.to = *(arrPtr + i);
PlayerState temp = player[c];
PlayerState temp2 = player[1-c];
if(is_king_under_check(c)){
make_move(possibleMove, player[c].b, BISHOP, c);
if(is_king_under_check(c)){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
continue;
}
}
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
make_move(possibleMove, player[c].b, BISHOP, c);
if(is_king_under_check(c) == TRUE){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
}else{
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = BISHOP;
mNode->promotion_choice = UNKNOWN;
mNode->next_move = NULL;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
/* free(mNode);*/
}
}
free(b_moves);
}
}
if(player[c].p & sq){
possibleMove.from = shift;
possibleMove.piece = PAWN;
Pos *p_moves = pawn_move(possibleMove, c);
unsigned int size = *(p_moves);
unsigned int *arrPtr = p_moves;
if(size > 0){
for(i = 1; i < size+1; i++){
possibleMove.to = *(arrPtr + i);
possibleMove.promotion_choice = UNKNOWN;
PlayerState temp = player[c];
PlayerState temp2 = player[1-c];
if(is_king_under_check(c)){
make_move(possibleMove, player[c].p, PAWN, c);
if(is_king_under_check(c)){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
continue;
}
}
if(RANK_OF(possibleMove.to) == '1' || RANK_OF(possibleMove.to) == '8'){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
int j = 0;
for(j = 0; j < 4; j++){
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->promotion_choice = UNKNOWN;
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = PAWN;
mNode->next_move = NULL;
if(j == 0) mNode->promotion_choice = QUEEN;
if(j == 1) mNode->promotion_choice = ROOK;
if(j == 2) mNode->promotion_choice = BISHOP;
if(j == 3) mNode->promotion_choice = NIGHT;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
/*free(mNode);*/
}
}
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
make_move(possibleMove, player[c].p, PAWN, c);
if(is_king_under_check(c) == TRUE){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
}
else{
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = PAWN;
mNode->promotion_choice = UNKNOWN;
mNode->next_move = NULL;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
/* free(mNode);*/
}
}
free(p_moves);
}
}
if(player[c].r & sq){
possibleMove.from = shift;
possibleMove.piece = ROOK;
Pos *r_moves = rook_move(possibleMove, c);
unsigned int size = *(r_moves);
unsigned int *arrPtr = r_moves;
if(size > 0){
for(i = 1; i < size+1; i++){
possibleMove.to = *(arrPtr + i);
PlayerState temp = player[c];
PlayerState temp2 = player[1-c];
if(is_king_under_check(c)){
make_move(possibleMove, player[c].r, ROOK, c);
if(is_king_under_check(c)){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
continue;
}
}
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
make_move(possibleMove, player[c].r, ROOK, c);
if(is_king_under_check(c) == TRUE){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
}else{
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = ROOK;
mNode->promotion_choice = UNKNOWN;
mNode->next_move = NULL;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
}
}
free(r_moves);
}
}
if(player[c].n & sq){
possibleMove.from = shift;
possibleMove.piece = NIGHT;
Pos *n_moves = knight_move(possibleMove, c);
unsigned int size = *(n_moves);
unsigned int *arrPtr = n_moves;
if(size > 0){
for(i = 1; i < size+1; i++){
possibleMove.to = *(arrPtr + i);
PlayerState temp = player[c];
PlayerState temp2 = player[1-c];
if(is_king_under_check(c)){
make_move(possibleMove, player[c].n, NIGHT, c);
if(is_king_under_check(c)){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
continue;
}
}
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
make_move(possibleMove, player[c].n, NIGHT, c);
if(is_king_under_check(c) == TRUE){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
}else{
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = NIGHT;
mNode->promotion_choice = UNKNOWN;
mNode->next_move = NULL;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
/*free(mNode);*/
}
}
free(n_moves);
}
}
if(player[c].q & sq){
possibleMove.from = shift;
possibleMove.piece = QUEEN;
Pos *q_moves = queen_move(possibleMove, c);
unsigned int size = *(q_moves);
unsigned int *arrPtr = q_moves;
if(size > 0){
for(i = 1; i < size+1; i++){
possibleMove.to = *(arrPtr + i);
PlayerState temp = player[c];
PlayerState temp2 = player[1-c];
if(is_king_under_check(c)){
make_move(possibleMove, player[c].q, QUEEN, c);
if(is_king_under_check(c)){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
continue;
}
}
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
make_move(possibleMove, player[c].q, QUEEN, c);
if(is_king_under_check(c)){
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
}else{
Move *mNode = (Move *)(calloc(1, sizeof(Move)));
mNode->from = shift;
mNode->to = *(arrPtr + i);
mNode->piece = QUEEN;
mNode->promotion_choice = UNKNOWN;
mNode->next_move = NULL;
player[c] = temp;
player[1-c] = temp2;
CurrentBoard = tempBoard;
link = save;
while(link->next_move != NULL){
link = link->next_move;
}
link->next_move = mNode;
(*pcount)++;
/*free(mNode);*/
}
}
free(q_moves);
}
}
}
if(*pcount > 0){
return TRUE;
}else{
return FALSE;
}
}
And the associated valgrind output:
==447557== 535,008 (12,792 direct, 522,216 indirect) bytes in 533 blocks
are definitely lost in loss record 47 of 47
==447557== at 0x4837B65: calloc (vg_replace_malloc.c:752)
==447557== by 0x10CA10: legal_moves (moves.c:24)
==447557== by 0x117059: run_mate1 (moves.c:1464)
==447557== by 0x117CBD: run_mate2 (moves.c:1599)
==447557== by 0x109C37: main (main.c:181)
Upvotes: 1
Views: 101
Answers (1)
Marco Bonelli
Reputation: 69377
In your legal_moves() function:
Move *save = (Move *)(calloc(1, sizeof(Move)));
Move *link = save;
*m = save;
Here you just completely lost any reference to the allocated memory that was passed by reference to the function, and there's no way of freeing it (actually, you still have list in is_checkmate(), but you don't use it). If legal_moves() does the allocation on its own, then there's no point in doing it prior to calling it in is_checkmate() (or anywhere else the function is used).
You could do:
Move *save = NULL;
unsigned int num = 0;
if (is_king_under_check(c) && !legal_moves(&save, c, &num)){
// ...
}
Also, as a rule of thumb: don't cast the result of malloc/calloc/realloc.
Upvotes: 2
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