[libc][tsearch] add tsearch functions

libc/config/linux/aarch64/entrypoints.txt

@@ -1116,6 +1116,12 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.search.lfind
     libc.src.search.lsearch
     libc.src.search.remque
+    libc.src.search.tdelete
+    libc.src.search.tdestroy
+    libc.src.search.tfind
+    libc.src.search.tsearch
+    libc.src.search.twalk
+    libc.src.search.twalk_r
 
     # threads.h entrypoints
     libc.src.threads.call_once

libc/config/linux/x86_64/entrypoints.txt

@@ -1298,6 +1298,12 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.search.lfind
     libc.src.search.lsearch
     libc.src.search.remque
+    libc.src.search.tdelete
+    libc.src.search.tdestroy
+    libc.src.search.tfind
+    libc.src.search.tsearch
+    libc.src.search.twalk
+    libc.src.search.twalk_r
 
     # threads.h entrypoints
     libc.src.threads.call_once

libc/fuzzing/__support/CMakeLists.txt

@@ -25,6 +25,14 @@ add_libc_fuzzer(
     -D__LIBC_EXPLICIT_SIMD_OPT
 )
 
+add_libc_fuzzer(
+  weak_avl_fuzz
+  SRCS
+    weak_avl_fuzz.cpp
+  DEPENDS
+    libc.src.__support.weak_avl
+)
+
 # TODO: FreeListHeap uses the _end symbol which conflicts with the _end symbol
 # defined by GPU start.cpp files so for now we exclude this fuzzer on GPU.
 if(LLVM_LIBC_FULL_BUILD AND NOT LIBC_TARGET_OS_IS_GPU)

libc/fuzzing/__support/weak_avl_fuzz.cpp

@@ -0,0 +1,94 @@
+//===-- weak_avl_fuzz.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc weak AVL implementations.
+///
+//===----------------------------------------------------------------------===//
+#include "hdr/types/ENTRY.h"
+#include "src/__support/CPP/bit.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/weak_avl.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+// A sequence of actions:
+// - Erase: a single byte valued (5, 6 mod 7) followed by an int
+// - Find: a single byte valued (4 mod 7) followed by an int
+// - FindOrInsert: a single byte valued (0,1,2,3 mod 7) followed by an int
+extern "C" size_t LLVMFuzzerMutate(uint8_t *data, size_t size, size_t max_size);
+extern "C" size_t LLVMFuzzerCustomMutator(uint8_t *data, size_t size,
+                                          size_t max_size, unsigned int seed) {
+  size = LLVMFuzzerMutate(data, size, max_size);
+  return size / (1 + sizeof(int)) * (1 + sizeof(int));
+}
+
+class AVLTree {
+  using Node = WeakAVLNode<int>;
+  Node *root = nullptr;
+  bool reversed = false;
+  static int compare(int a, int b) { return (a > b) - (a < b); }
+  static int reverse_compare(int a, int b) { return (b > a) - (b < a); }
+
+public:
+  AVLTree(bool reversed = false) : reversed(reversed) {}
+  bool find(int key) {
+    return Node::find(root, key, reversed ? reverse_compare : compare);
+  }
+  bool find_or_insert(int key) {
+    return Node::find_or_insert(root, key,
+                                reversed ? reverse_compare : compare);
+  }
+  bool erase(int key) {
+    Node *node = Node::find(root, key, reversed ? reverse_compare : compare);
+    if (node)
+      Node::erase(root, node);
+    return node;
+  }
+  ~AVLTree() { Node::destroy(root); }
+};
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  AVLTree tree1;
+  AVLTree tree2(true);
+  for (size_t i = 0; i + (1 + sizeof(int)) <= size; i += 1 + sizeof(int)) {
+    uint8_t action = data[i];
+    int key;
+    __builtin_memcpy(&key, data + i + 1, sizeof(int));
+    if (action % 7 == 4) {
+      // Find
+      bool res1 = tree1.find(key);
+      bool res2 = tree2.find(key);
+      if (res1 != res2)
+        __builtin_trap();
+
+    } else if (action % 7 == 5 || action % 7 == 6) {
+      // Erase
+      bool res1 = tree1.erase(key);
+      bool res2 = tree2.erase(key);
+      if (res1 != res2)
+        __builtin_trap();
+      if (tree1.find(key))
+        __builtin_trap();
+      if (tree2.find(key))
+        __builtin_trap();
+    } else {
+      // FindOrInsert
+      bool res1 = tree1.find_or_insert(key);
+      bool res2 = tree2.find_or_insert(key);
+      if (res1 != res2)
+        __builtin_trap();
+      if (!tree1.find(key))
+        __builtin_trap();
+      if (!tree2.find(key))
+        __builtin_trap();
+    }
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/hdr/types/CMakeLists.txt

@@ -487,3 +487,21 @@ add_proxy_header_library(
   FULL_BUILD_DEPENDS
     libc.include.llvm-libc-types.gid_t
 )
+
+add_proxy_header_library(
+  posix_tnode
+  HDRS
+    posix_tnode.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.posix_tnode
+    libc.include.search
+)
+
+add_proxy_header_library(
+  VISIT
+  HDRS
+    VISIT.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.VISIT
+    libc.include.search
+)

libc/hdr/types/VISIT.h

@@ -0,0 +1,22 @@
+//===-- Definition of macros from VISIT -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_HDR_TYPES_VISIT_H
+#define LLVM_LIBC_HDR_TYPES_VISIT_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/VISIT.h"
+
+#else // Overlay mode
+
+#include <search.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_VISIT_H

libc/hdr/types/posix_tnode.h

@@ -0,0 +1,28 @@
+//===-- Definition of macros from posix_tnode -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_HDR_TYPES_POSIX_TNODE_H
+#define LLVM_LIBC_HDR_TYPES_POSIX_TNODE_H
+
+// posix_tnode is introduced in POSIX.1-2024.
+// this may result in problems when overlaying on older systems.
+// internal code should use __llvm_libc_tnode.
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/posix_tnode.h"
+#define __llvm_libc_tnode posix_tnode
+
+#else // Overlay mode
+
+#include <search.h>
+typedef void __llvm_libc_tnode;
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_POSIX_TNODE_H

libc/include/CMakeLists.txt

@@ -273,9 +273,13 @@ add_header_macro(
     .llvm-libc-types.ACTION
     .llvm-libc-types.ENTRY
     .llvm-libc-types.VISIT
+    .llvm-libc-types.posix_tnode
     .llvm-libc-types.__search_compare_t
     .llvm-libc-types.size_t
     .llvm-libc-types.struct_hsearch_data
+    .llvm-libc-types.__action_closure_fn_t
+    .llvm-libc-types.__action_fn_t
+    .llvm-libc-types.__free_fn_t
     .llvm_libc_common_h
 )
 

libc/include/llvm-libc-types/CMakeLists.txt

@@ -52,6 +52,7 @@ add_header(off_t HDR off_t.h)
 add_header(once_flag HDR once_flag.h DEPENDS .__futex_word)
 add_header(posix_spawn_file_actions_t HDR posix_spawn_file_actions_t.h)
 add_header(posix_spawnattr_t HDR posix_spawnattr_t.h)
+add_header(posix_tnode HDR posix_tnode.h)
 add_header(pthread_attr_t HDR pthread_attr_t.h DEPENDS .size_t)
 add_header(pthread_condattr_t HDR pthread_condattr_t.h DEPENDS .clockid_t)
 add_header(pthread_key_t HDR pthread_key_t.h)
@@ -310,3 +311,18 @@ add_header(EFI_SYSTEM_TABLE
     .EFI_TABLE_HEADER
     .char16_t
 )
+add_header(__action_closure_fn_t 
+  HDR 
+    __action_closure_fn_t.h 
+  DEPENDS 
+    .posix_tnode 
+    .VISIT
+)
+add_header(__action_fn_t 
+  HDR 
+    __action_fn_t.h 
+  DEPENDS 
+    .posix_tnode 
+    .VISIT
+)
+add_header(__free_fn_t HDR __free_fn_t.h)

libc/include/llvm-libc-types/__action_closure_fn_t.h

@@ -0,0 +1,17 @@
+//===-- Definition of type __action_closure_fn_t --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES___ACTION_CLOSURE_FN_T_H
+#define LLVM_LIBC_TYPES___ACTION_CLOSURE_FN_T_H
+
+#include "VISIT.h"
+#include "posix_tnode.h"
+
+typedef void (*__action_closure_fn_t)(const posix_tnode *, VISIT, void *);
+
+#endif // LLVM_LIBC_TYPES___ACTION_CLOSURE_FN_T_H

libc/include/llvm-libc-types/__action_fn_t.h

@@ -0,0 +1,17 @@
+//===-- Definition of type __action_fn_t ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES___ACTION_FN_T_H
+#define LLVM_LIBC_TYPES___ACTION_FN_T_H
+
+#include "VISIT.h"
+#include "posix_tnode.h"
+
+typedef void (*__action_fn_t)(const posix_tnode *, VISIT, int);
+
+#endif // LLVM_LIBC_TYPES___ACTION_FN_T_H

libc/include/llvm-libc-types/__free_fn_t.h

@@ -0,0 +1,14 @@
+//===-- Definition of type __free_fn_t ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES___FREE_FN_T_H
+#define LLVM_LIBC_TYPES___FREE_FN_T_H
+
+typedef void (*__free_fn_t)(void *);
+
+#endif // LLVM_LIBC_TYPES___FREE_FN_T_H

libc/include/llvm-libc-types/posix_tnode.h

@@ -0,0 +1,17 @@
+//===-- Definition of type posix_tnode--------------- ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES_POSIX_TNODE_H
+#define LLVM_LIBC_TYPES_POSIX_TNODE_H
+
+// Following POSIX.1-2024 and Austin Group Defect Report 1011:
+// https://austingroupbugs.net/view.php?id=1011
+// Define posix_tnode as void to provide both type safety and compatibility.
+typedef void posix_tnode;
+
+#endif // LLVM_LIBC_TYPES_POSIX_TNODE_H

libc/include/search.yaml

@@ -7,6 +7,10 @@ types:
   - type_name: VISIT
   - type_name: __search_compare_t
   - type_name: struct_hsearch_data
+  - type_name: posix_tnode
+  - type_name: __action_closure_fn_t
+  - type_name: __action_fn_t
+  - type_name: __free_fn_t
 enums: []
 objects: []
 functions:
@@ -80,3 +84,47 @@ functions:
       - type: size_t *
       - type: size_t
       - type: __search_compare_t
+  - name: tdelete
+    standards:
+      - posix
+    return_type: void *
+    arguments:
+      - type: const void *__restrict
+      - type: posix_tnode **__restrict
+      - type: __search_compare_t
+  - name: tfind
+    standards:
+      - posix
+    return_type: posix_tnode *
+    arguments:
+      - type: const void *
+      - type: posix_tnode * const *
+      - type: __search_compare_t
+  - name: tsearch
+    standards:
+      - posix
+    return_type: posix_tnode *
+    arguments:
+      - type: const void *
+      - type: posix_tnode **
+      - type: __search_compare_t
+  - name: twalk
+    standards:
+      - posix
+    return_type: void
+    arguments:
+      - type: const posix_tnode *
+      - type: __action_fn_t
+  - name: twalk_r
+    standards: gnu
+    return_type: void
+    arguments:
+      - type: const posix_tnode *
+      - type: __action_closure_fn_t
+      - type: void *
+  - name: tdestroy
+    standards: gnu
+    return_type: void
+    arguments:
+      - type: posix_tnode *
+      - type: __free_fn_t

libc/src/__support/CMakeLists.txt

@@ -391,6 +391,20 @@ add_header_library(
     libc.src.__support.macros.attributes
 )
 
+add_header_library(
+  weak_avl
+  HDRS
+    weak_avl.h
+  DEPENDS
+    libc.hdr.stdint_proxy
+    libc.src.__support.CPP.bit
+    libc.src.__support.CPP.new
+    libc.src.__support.CPP.utility
+    libc.src.__support.libc_assert
+    libc.src.__support.macros.attributes
+    libc.src.__support.macros.config
+)
+
 add_subdirectory(FPUtil)
 add_subdirectory(OSUtil)
 add_subdirectory(StringUtil)