From: Matthieu Longo Date: Fri, 30 Jan 2026 15:08:41 +0000 (+0000) Subject: libiberty: add helper to swap doubly-linked list wrappers X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7722c043f05deb75b4b5ab92740d0d491101f5c2;p=thirdparty%2Fgcc.git libiberty: add helper to swap doubly-linked list wrappers This patch introduces a new helper to swap the contents of two doubly-linked list wrappers. The new *_swap_lists operation exchanges the first, last, and size fields, allowing two lists to be swapped efficiently without iterating over their elements. This helper is intended for cases where the ownership of a list must be exchanged but swapping wrapper pointers is not possible. For simple references to lists, when wrappers are dynamically allocated, swapping the wrapper pointers themselves is sufficient and remains the preferred approach. This change adds the necessary declaration and definition macros to doubly-linked-list.h and integrates them into the set of mutative list operations. The testsuite is updated accordingly to cover the new functionality. include/ChangeLog: * doubly-linked-list.h (LINKED_LIST_SWAP_LISTS): Add new helper. (LINKED_LIST_DECL_SWAP_LISTS): Likewise. (LINKED_LIST_DEFN_SWAP_LISTS): Likewise. (LWRAPPERTYPE##_swap_lists): Likewise. libiberty/ChangeLog: * testsuite/test-doubly-linked-list.c: Update. --- diff --git a/include/doubly-linked-list.h b/include/doubly-linked-list.h index 0108af73f96..d46d773800b 100644 --- a/include/doubly-linked-list.h +++ b/include/doubly-linked-list.h @@ -229,14 +229,13 @@ LTYPE##_remove (LWRAPPERTYPE *wrapper, LTYPE *node) \ return previous; \ } -/* Generic swap. */ +/* Swap two nodes in a list. */ #define LINKED_LIST_SWAP(LTYPE) LTYPE##_swap #define LINKED_LIST_DECL_SWAP(LWRAPPERTYPE, LTYPE, EXPORT) \ EXPORT void \ LTYPE##_swap (LWRAPPERTYPE *wrapper, LTYPE *node1, LTYPE *node2) -/* Swap two nodes in a list. */ #define LINKED_LIST_DEFN_SWAP(LWRAPPERTYPE, LTYPE, EXPORT) \ EXPORT void \ LTYPE##_swap (LWRAPPERTYPE *wrapper, LTYPE *node1, LTYPE *node2) \ @@ -276,6 +275,34 @@ LTYPE##_swap (LWRAPPERTYPE *wrapper, LTYPE *node1, LTYPE *node2) \ } \ } +/* Swap two lists, i.e. swap two wrappers. */ +#define LINKED_LIST_SWAP_LISTS(LWRAPPERTYPE) LWRAPPERTYPE##_swap_lists + +#define LINKED_LIST_DECL_SWAP_LISTS(LWRAPPERTYPE, LTYPE, EXPORT) \ + EXPORT void \ + LWRAPPERTYPE##_swap_lists (LWRAPPERTYPE *left_w, LWRAPPERTYPE *right_w) + +#define LINKED_LIST_DEFN_SWAP_LISTS(LWRAPPERTYPE, LTYPE, EXPORT) \ +EXPORT void \ +LWRAPPERTYPE##_swap_lists (LWRAPPERTYPE *left_w, LWRAPPERTYPE *right_w) \ +{ \ + { \ + LTYPE *temp = left_w->first; \ + left_w->first = right_w->first; \ + right_w->first = temp; \ + } \ + { \ + LTYPE *temp = left_w->last; \ + left_w->last = right_w->last; \ + right_w->last = temp; \ + } \ + { \ + unsigned int temp = left_w->size; \ + left_w->size = right_w->size; \ + right_w->size = temp; \ + } \ +} + /* Note: all the mutative operations below also update the data in the wrapper, i.e. first, last and size. */ #define LINKED_LIST_MUTATIVE_OPS_PROTOTYPE(LWRAPPERTYPE, LTYPE, EXPORT) \ @@ -285,7 +312,8 @@ LTYPE##_swap (LWRAPPERTYPE *wrapper, LTYPE *node1, LTYPE *node2) \ LINKED_LIST_DECL_POP_FRONT(LWRAPPERTYPE, LTYPE, EXPORT); \ LINKED_LIST_DECL_POP_BACK(LWRAPPERTYPE, LTYPE, EXPORT); \ LINKED_LIST_DECL_REMOVE(LWRAPPERTYPE, LTYPE, EXPORT); \ - LINKED_LIST_DECL_SWAP(LWRAPPERTYPE, LTYPE, EXPORT) + LINKED_LIST_DECL_SWAP(LWRAPPERTYPE, LTYPE, EXPORT); \ + LINKED_LIST_DECL_SWAP_LISTS(LWRAPPERTYPE, LTYPE, EXPORT) #define LINKED_LIST_MUTATIVE_OPS_DECL(LWRAPPERTYPE, LTYPE, EXPORT) \ LINKED_LIST_DEFN_APPEND(LWRAPPERTYPE, LTYPE, EXPORT) \ @@ -294,7 +322,8 @@ LTYPE##_swap (LWRAPPERTYPE *wrapper, LTYPE *node1, LTYPE *node2) \ LINKED_LIST_DEFN_POP_FRONT(LWRAPPERTYPE, LTYPE, EXPORT) \ LINKED_LIST_DEFN_POP_BACK(LWRAPPERTYPE, LTYPE, EXPORT) \ LINKED_LIST_DEFN_REMOVE(LWRAPPERTYPE, LTYPE, EXPORT) \ - LINKED_LIST_DEFN_SWAP(LWRAPPERTYPE, LTYPE, EXPORT) + LINKED_LIST_DEFN_SWAP(LWRAPPERTYPE, LTYPE, EXPORT); \ + LINKED_LIST_DEFN_SWAP_LISTS(LWRAPPERTYPE, LTYPE, EXPORT) /* Sorting. */ diff --git a/libiberty/testsuite/test-doubly-linked-list.c b/libiberty/testsuite/test-doubly-linked-list.c index 93fe19a27ae..914bc7934e3 100644 --- a/libiberty/testsuite/test-doubly-linked-list.c +++ b/libiberty/testsuite/test-doubly-linked-list.c @@ -190,6 +190,8 @@ const int EXPECT_7 [] = { 10, 9, 2, 4, 3, 8, 11 }; const int EXPECT_8 [] = { 2, 3, 4, 8, 9, 10, 11 }; const int EXPECT_9 [] = { 3, 4, 8, 9, 10, 11 }; const int EXPECT_10 [] = { 3, 4, 8, 9, 10 }; +const int EXPECT_11 [] = { 20, 21, 22 }; +const int EXPECT_12 [] = { 3, 4, 8, 9, 10 }; const struct test_data_t test_data[] = { { .content = EXPECT_0, .size = sizeof(EXPECT_0) / sizeof(EXPECT_0[0]) }, { .content = EXPECT_1, .size = sizeof(EXPECT_1) / sizeof(EXPECT_1[0]) }, @@ -202,6 +204,8 @@ const struct test_data_t test_data[] = { { .content = EXPECT_8, .size = sizeof(EXPECT_8) / sizeof(EXPECT_8[0]) }, { .content = EXPECT_9, .size = sizeof(EXPECT_9) / sizeof(EXPECT_9[0]) }, { .content = EXPECT_10, .size = sizeof(EXPECT_10) / sizeof(EXPECT_10[0]) }, + { .content = EXPECT_11, .size = sizeof(EXPECT_11) / sizeof(EXPECT_11[0]) }, + { .content = EXPECT_12, .size = sizeof(EXPECT_12) / sizeof(EXPECT_12[0]) }, }; int main (void) @@ -272,5 +276,23 @@ int main (void) LINKED_LIST_POP_BACK(ListNodeType) (&wrapper); failures += ! check ("pop_back", &test_data[10], &wrapper); + LinkedListWrapperType other_wrapper = { + .first = NULL, + .last = NULL, + .size = 0, + }; + + LINKED_LIST_APPEND(ListNodeType) (&other_wrapper, l_new_node (20)); + LINKED_LIST_APPEND(ListNodeType) (&other_wrapper, l_new_node (21)); + LINKED_LIST_APPEND(ListNodeType) (&other_wrapper, l_new_node (22)); + + /* Swap wrappers once. */ + LINKED_LIST_SWAP_LISTS (LinkedListWrapperType) (&wrapper, &other_wrapper); + failures += ! check ("swap wrappers once", &test_data[11], &wrapper); + + /* Swap wrappers twice. */ + LINKED_LIST_SWAP_LISTS (LinkedListWrapperType) (&wrapper, &other_wrapper); + failures += ! check ("swap wrappers twice", &test_data[12], &wrapper); + exit (failures ? EXIT_FAILURE : EXIT_SUCCESS); }