[libc-commits] [libc] [libc] Add Annex K qsort_s definition and tests (PR #198797)
Victor Campos via libc-commits
libc-commits at lists.llvm.org
Fri Jun 26 10:03:08 PDT 2026
https://github.com/vhscampos updated https://github.com/llvm/llvm-project/pull/198797
>From 11b4f57da5ff3aac0634cc5bccbf3ccb450fb3ad Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Wed, 20 May 2026 12:56:41 +0100
Subject: [PATCH 1/5] [libc] Refactor qsort code
This patch makes the following changes:
- Refactor the internal sorting functions to reduce code duplication.
- Move the testing machinery done for the testing of `qsort_r` to a
shared place.
These changes are done in anticipation to the introduction of Annex K's
`qsort_s`. This function shares most of its semantics with `qsort_r`,
therefore most of the testing logic can be shared between the two.
Besides, `qsort`, `qsort_r` and `qsort_r` are all very similar, hence we
can attempt to reduce duplication a bit more.
---
libc/src/stdlib/qsort.cpp | 6 +-
libc/src/stdlib/qsort_r.cpp | 7 +-
libc/src/stdlib/qsort_util.h | 25 +++-
libc/test/src/stdlib/CMakeLists.txt | 3 +-
libc/test/src/stdlib/QsortReentrantTest.h | 150 ++++++++++++++++++++++
libc/test/src/stdlib/qsort_r_test.cpp | 136 +-------------------
6 files changed, 178 insertions(+), 149 deletions(-)
create mode 100644 libc/test/src/stdlib/QsortReentrantTest.h
diff --git a/libc/src/stdlib/qsort.cpp b/libc/src/stdlib/qsort.cpp
index f66b686d4e54b..46a74fb9118a3 100644
--- a/libc/src/stdlib/qsort.cpp
+++ b/libc/src/stdlib/qsort.cpp
@@ -18,11 +18,7 @@ LLVM_LIBC_FUNCTION(void, qsort,
(void *array, size_t array_size, size_t elem_size,
int (*compare)(const void *, const void *))) {
- const auto is_less = [compare](const void *a, const void *b) -> bool {
- return compare(a, b) < 0;
- };
-
- internal::unstable_sort(array, array_size, elem_size, is_less);
+ internal::unstable_sort(array, array_size, elem_size, compare);
}
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/qsort_r.cpp b/libc/src/stdlib/qsort_r.cpp
index 47448201eddbd..65afcee77885d 100644
--- a/libc/src/stdlib/qsort_r.cpp
+++ b/libc/src/stdlib/qsort_r.cpp
@@ -18,12 +18,7 @@ LLVM_LIBC_FUNCTION(void, qsort_r,
(void *array, size_t array_size, size_t elem_size,
int (*compare)(const void *, const void *, void *),
void *arg)) {
-
- const auto is_less = [compare, arg](const void *a, const void *b) -> bool {
- return compare(a, b, arg) < 0;
- };
-
- internal::unstable_sort(array, array_size, elem_size, is_less);
+ internal::unstable_sort(array, array_size, elem_size, compare, arg);
}
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/qsort_util.h b/libc/src/stdlib/qsort_util.h
index 7882b829d3274..24f41907d78c5 100644
--- a/libc/src/stdlib/qsort_util.h
+++ b/libc/src/stdlib/qsort_util.h
@@ -64,10 +64,29 @@ LIBC_INLINE void unstable_sort_impl(void *array, size_t array_len,
}
template <typename F>
+LIBC_INLINE void unstable_sort_dispatch(void *array, size_t array_len,
+ size_t elem_size, F is_less) {
+ constexpr bool use_quick_sort = (LIBC_QSORT_IMPL == LIBC_QSORT_QUICK_SORT);
+ unstable_sort_impl<use_quick_sort>(array, array_len, elem_size, is_less);
+}
+
+template <typename CmpFn>
+LIBC_INLINE void unstable_sort(void *array, size_t array_len, size_t elem_size,
+ CmpFn compare) {
+ const auto is_less = [compare](const void *a, const void *b) -> bool {
+ return compare(a, b) < 0;
+ };
+ unstable_sort_dispatch(array, array_len, elem_size, is_less);
+}
+
+template <typename CmpFn>
LIBC_INLINE void unstable_sort(void *array, size_t array_len, size_t elem_size,
- const F &is_less) {
-#define USE_QUICK_SORT ((LIBC_QSORT_IMPL) == (LIBC_QSORT_QUICK_SORT))
- unstable_sort_impl<USE_QUICK_SORT, F>(array, array_len, elem_size, is_less);
+ CmpFn compare, void *context) {
+ const auto is_less = [compare, context](const void *a,
+ const void *b) -> bool {
+ return compare(a, b, context) < 0;
+ };
+ unstable_sort_dispatch(array, array_len, elem_size, is_less);
}
} // namespace internal
diff --git a/libc/test/src/stdlib/CMakeLists.txt b/libc/test/src/stdlib/CMakeLists.txt
index a7b7c9269fcee..270a7a2291293 100644
--- a/libc/test/src/stdlib/CMakeLists.txt
+++ b/libc/test/src/stdlib/CMakeLists.txt
@@ -360,8 +360,9 @@ add_libc_test(
libc-stdlib-tests
SRCS
qsort_r_test.cpp
+ HDRS
+ QsortReentrantTest.h
DEPENDS
- libc.hdr.types.size_t
libc.src.stdlib.qsort_r
)
diff --git a/libc/test/src/stdlib/QsortReentrantTest.h b/libc/test/src/stdlib/QsortReentrantTest.h
new file mode 100644
index 0000000000000..4453a27b01f38
--- /dev/null
+++ b/libc/test/src/stdlib/QsortReentrantTest.h
@@ -0,0 +1,150 @@
+
+//===-- A template class for testing reentrant qsort functions --*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "test/UnitTest/Test.h"
+
+template <typename QsortFnTy, typename SizeTy>
+class QsortReentrantTest : public LIBC_NAMESPACE::testing::Test {
+private:
+ static int int_compare_count(const void *l, const void *r, void *count_arg) {
+ int li = *static_cast<const int *>(l);
+ int ri = *static_cast<const int *>(r);
+ SizeTy *count = static_cast<SizeTy *>(count_arg);
+ *count = *count + 1;
+ if (li == ri)
+ return 0;
+ else if (li > ri)
+ return 1;
+ else
+ return -1;
+ }
+
+ struct PriorityVal {
+ int priority;
+ int size;
+ };
+
+ static int compare_priority_val(const PriorityVal *l, const PriorityVal *r) {
+ // Subtracting the priorities is unsafe, but it's fine for this test.
+ int priority_diff = l->priority - r->priority;
+ if (priority_diff != 0) {
+ return priority_diff;
+ }
+ if (l->size == r->size) {
+ return 0;
+ } else if (l->size > r->size) {
+ return 1;
+ } else {
+ return -1;
+ }
+ }
+
+ // The following test is intended to mimic the CPP library pattern of having a
+ // comparison function that takes a specific type, which is passed to a
+ // library that then needs to sort an array of that type. The library can't
+ // safely pass the comparison function to qsort because a function that takes
+ // const T* being cast to a function that takes const void* is undefined
+ // behavior. The safer pattern is to pass a type erased comparator that calls
+ // into the typed comparator to qsort_r.
+ template <typename T>
+ static int type_erased_comp(const void *l, const void *r,
+ void *erased_func_ptr) {
+ typedef int (*TypedComp)(const T *, const T *);
+ TypedComp typed_func_ptr = reinterpret_cast<TypedComp>(erased_func_ptr);
+ const T *lt = static_cast<const T *>(l);
+ const T *rt = static_cast<const T *>(r);
+ return typed_func_ptr(lt, rt);
+ }
+
+public:
+ void sorted_array(QsortFnTy func) {
+ int array[25] = {10, 23, 33, 35, 55, 70, 71, 100, 110,
+ 123, 133, 135, 155, 170, 171, 1100, 1110, 1123,
+ 1133, 1135, 1155, 1170, 1171, 11100, 12310};
+ constexpr SizeTy ARRAY_SIZE = sizeof(array) / sizeof(int);
+
+ SizeTy count = 0;
+
+ func(array, ARRAY_SIZE, sizeof(int), int_compare_count, &count);
+
+ ASSERT_LE(array[0], 10);
+ ASSERT_LE(array[1], 23);
+ ASSERT_LE(array[2], 33);
+ ASSERT_LE(array[3], 35);
+ ASSERT_LE(array[4], 55);
+ ASSERT_LE(array[5], 70);
+ ASSERT_LE(array[6], 71);
+ ASSERT_LE(array[7], 100);
+ ASSERT_LE(array[8], 110);
+ ASSERT_LE(array[9], 123);
+ ASSERT_LE(array[10], 133);
+ ASSERT_LE(array[11], 135);
+ ASSERT_LE(array[12], 155);
+ ASSERT_LE(array[13], 170);
+ ASSERT_LE(array[14], 171);
+ ASSERT_LE(array[15], 1100);
+ ASSERT_LE(array[16], 1110);
+ ASSERT_LE(array[17], 1123);
+ ASSERT_LE(array[18], 1133);
+ ASSERT_LE(array[19], 1135);
+ ASSERT_LE(array[20], 1155);
+ ASSERT_LE(array[21], 1170);
+ ASSERT_LE(array[22], 1171);
+ ASSERT_LE(array[23], 11100);
+ ASSERT_LE(array[24], 12310);
+
+ // This is a sorted list, but there still have to have been at least N - 1
+ // comparisons made.
+ ASSERT_GE(count, ARRAY_SIZE - 1);
+ }
+
+ void reverse_sorted_array(QsortFnTy func) {
+ int array[25] = {25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13,
+ 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
+ constexpr SizeTy ARRAY_SIZE = sizeof(array) / sizeof(int);
+
+ SizeTy count = 0;
+
+ func(array, ARRAY_SIZE, sizeof(int), int_compare_count, &count);
+
+ for (int i = 0; i < int(ARRAY_SIZE - 1); ++i)
+ ASSERT_LE(array[i], i + 1);
+
+ ASSERT_GE(count, ARRAY_SIZE);
+ }
+
+ void safe_type_erasure(QsortFnTy func) {
+ PriorityVal array[5] = {
+ {10, 3}, {1, 10}, {-1, 100}, {10, 0}, {3, 3},
+ };
+ constexpr SizeTy ARRAY_SIZE = sizeof(array) / sizeof(PriorityVal);
+
+ func(array, ARRAY_SIZE, sizeof(PriorityVal), type_erased_comp<PriorityVal>,
+ reinterpret_cast<void *>(compare_priority_val));
+
+ EXPECT_EQ(array[0].priority, -1);
+ EXPECT_EQ(array[0].size, 100);
+ EXPECT_EQ(array[1].priority, 1);
+ EXPECT_EQ(array[1].size, 10);
+ EXPECT_EQ(array[2].priority, 3);
+ EXPECT_EQ(array[2].size, 3);
+ EXPECT_EQ(array[3].priority, 10);
+ EXPECT_EQ(array[3].size, 0);
+ EXPECT_EQ(array[4].priority, 10);
+ EXPECT_EQ(array[4].size, 3);
+ }
+};
+
+#define QSORTREENTRANT_TEST(name, func, sizetype) \
+ using LlvmLibc##name##Test = QsortReentrantTest<decltype(func), sizetype>; \
+ TEST_F(LlvmLibc##name##Test, SortedArray) { sorted_array(func); } \
+ TEST_F(LlvmLibc##name##Test, ReverseSortedArray) { \
+ reverse_sorted_array(func); \
+ } \
+ TEST_F(LlvmLibc##name##Test, SafeTypeErasure) { safe_type_erasure(func); }
diff --git a/libc/test/src/stdlib/qsort_r_test.cpp b/libc/test/src/stdlib/qsort_r_test.cpp
index f18923618ed5e..b5dafca749525 100644
--- a/libc/test/src/stdlib/qsort_r_test.cpp
+++ b/libc/test/src/stdlib/qsort_r_test.cpp
@@ -7,138 +7,6 @@
//===----------------------------------------------------------------------===//
#include "src/stdlib/qsort_r.h"
+#include "QsortReentrantTest.h"
-#include "test/UnitTest/Test.h"
-
-#include "hdr/types/size_t.h"
-
-static int int_compare_count(const void *l, const void *r, void *count_arg) {
- int li = *reinterpret_cast<const int *>(l);
- int ri = *reinterpret_cast<const int *>(r);
- size_t *count = reinterpret_cast<size_t *>(count_arg);
- *count = *count + 1;
- if (li == ri)
- return 0;
- else if (li > ri)
- return 1;
- else
- return -1;
-}
-
-TEST(LlvmLibcQsortRTest, SortedArray) {
- int array[25] = {10, 23, 33, 35, 55, 70, 71, 100, 110,
- 123, 133, 135, 155, 170, 171, 1100, 1110, 1123,
- 1133, 1135, 1155, 1170, 1171, 11100, 12310};
- constexpr size_t ARRAY_SIZE = sizeof(array) / sizeof(int);
-
- size_t count = 0;
-
- LIBC_NAMESPACE::qsort_r(array, ARRAY_SIZE, sizeof(int), int_compare_count,
- &count);
-
- ASSERT_LE(array[0], 10);
- ASSERT_LE(array[1], 23);
- ASSERT_LE(array[2], 33);
- ASSERT_LE(array[3], 35);
- ASSERT_LE(array[4], 55);
- ASSERT_LE(array[5], 70);
- ASSERT_LE(array[6], 71);
- ASSERT_LE(array[7], 100);
- ASSERT_LE(array[8], 110);
- ASSERT_LE(array[9], 123);
- ASSERT_LE(array[10], 133);
- ASSERT_LE(array[11], 135);
- ASSERT_LE(array[12], 155);
- ASSERT_LE(array[13], 170);
- ASSERT_LE(array[14], 171);
- ASSERT_LE(array[15], 1100);
- ASSERT_LE(array[16], 1110);
- ASSERT_LE(array[17], 1123);
- ASSERT_LE(array[18], 1133);
- ASSERT_LE(array[19], 1135);
- ASSERT_LE(array[20], 1155);
- ASSERT_LE(array[21], 1170);
- ASSERT_LE(array[22], 1171);
- ASSERT_LE(array[23], 11100);
- ASSERT_LE(array[24], 12310);
-
- // This is a sorted list, but there still have to have been at least N - 1
- // comparisons made.
- ASSERT_GE(count, ARRAY_SIZE - 1);
-}
-
-TEST(LlvmLibcQsortRTest, ReverseSortedArray) {
- int array[25] = {25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13,
- 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
- constexpr size_t ARRAY_SIZE = sizeof(array) / sizeof(int);
-
- size_t count = 0;
-
- LIBC_NAMESPACE::qsort_r(array, ARRAY_SIZE, sizeof(int), int_compare_count,
- &count);
-
- for (int i = 0; i < int(ARRAY_SIZE - 1); ++i)
- ASSERT_LE(array[i], i + 1);
-
- ASSERT_GE(count, ARRAY_SIZE);
-}
-
-// The following test is intended to mimic the CPP library pattern of having a
-// comparison function that takes a specific type, which is passed to a library
-// that then needs to sort an array of that type. The library can't safely pass
-// the comparison function to qsort because a function that takes const T*
-// being cast to a function that takes const void* is undefined behavior. The
-// safer pattern is to pass a type erased comparator that calls into the typed
-// comparator to qsort_r.
-
-struct PriorityVal {
- int priority;
- int size;
-};
-
-static int compare_priority_val(const PriorityVal *l, const PriorityVal *r) {
- // Subtracting the priorities is unsafe, but it's fine for this test.
- int priority_diff = l->priority - r->priority;
- if (priority_diff != 0) {
- return priority_diff;
- }
- if (l->size == r->size) {
- return 0;
- } else if (l->size > r->size) {
- return 1;
- } else {
- return -1;
- }
-}
-
-template <typename T>
-static int type_erased_comp(const void *l, const void *r,
- void *erased_func_ptr) {
- typedef int (*TypedComp)(const T *, const T *);
- TypedComp typed_func_ptr = reinterpret_cast<TypedComp>(erased_func_ptr);
- const T *lt = reinterpret_cast<const T *>(l);
- const T *rt = reinterpret_cast<const T *>(r);
- return typed_func_ptr(lt, rt);
-}
-
-TEST(LlvmLibcQsortRTest, SafeTypeErasure) {
- PriorityVal array[5] = {
- {10, 3}, {1, 10}, {-1, 100}, {10, 0}, {3, 3},
- };
- constexpr size_t ARRAY_SIZE = sizeof(array) / sizeof(PriorityVal);
-
- LIBC_NAMESPACE::qsort_r(array, ARRAY_SIZE, sizeof(PriorityVal),
- type_erased_comp<PriorityVal>,
- reinterpret_cast<void *>(compare_priority_val));
-
- EXPECT_EQ(array[0].priority, -1);
- EXPECT_EQ(array[0].size, 100);
- EXPECT_EQ(array[1].priority, 1);
- EXPECT_EQ(array[1].size, 10);
- EXPECT_EQ(array[2].priority, 3);
- EXPECT_EQ(array[2].size, 3);
- EXPECT_EQ(array[3].priority, 10);
- EXPECT_EQ(array[3].size, 0);
- EXPECT_EQ(array[4].priority, 10);
- EXPECT_EQ(array[4].size, 3);
-}
+QSORTREENTRANT_TEST(QsortR, LIBC_NAMESPACE::qsort_r, size_t)
>From 4551535fb09cc7665dbd93cbcb9c19915638c31b Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Wed, 20 May 2026 14:29:59 +0100
Subject: [PATCH 2/5] Fix clang-format
---
libc/test/src/stdlib/qsort_r_test.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libc/test/src/stdlib/qsort_r_test.cpp b/libc/test/src/stdlib/qsort_r_test.cpp
index b5dafca749525..b1fff5a1bc3dd 100644
--- a/libc/test/src/stdlib/qsort_r_test.cpp
+++ b/libc/test/src/stdlib/qsort_r_test.cpp
@@ -6,7 +6,7 @@
//
//===----------------------------------------------------------------------===//
-#include "src/stdlib/qsort_r.h"
#include "QsortReentrantTest.h"
+#include "src/stdlib/qsort_r.h"
QSORTREENTRANT_TEST(QsortR, LIBC_NAMESPACE::qsort_r, size_t)
>From b7eb019be4b4885cbd0815844d7c81a0c80ae29b Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Wed, 20 May 2026 12:57:24 +0100
Subject: [PATCH 3/5] [libc] Add Annex K qsort_s definition and tests
This patch introduces Annex K's `qsort_s`.
Since its semantics are very similar to the ones for `qsort_r`, the two
share the same testing logic, except that for `qsort_s` we also test the
constraint violation semantics.
---
libc/config/baremetal/aarch64/entrypoints.txt | 1 +
libc/config/baremetal/arm/entrypoints.txt | 1 +
libc/config/linux/aarch64/entrypoints.txt | 1 +
libc/config/linux/x86_64/entrypoints.txt | 1 +
libc/include/CMakeLists.txt | 1 +
libc/include/llvm-libc-types/CMakeLists.txt | 1 +
.../llvm-libc-types/__qsortscompare_t.h | 14 ++++
libc/include/stdlib.yaml | 13 ++++
libc/src/stdlib/CMakeLists.txt | 16 +++++
libc/src/stdlib/qsort_s.cpp | 47 +++++++++++++
libc/src/stdlib/qsort_s.h | 24 +++++++
libc/test/src/stdlib/CMakeLists.txt | 16 +++++
libc/test/src/stdlib/qsort_s_test.cpp | 68 +++++++++++++++++++
13 files changed, 204 insertions(+)
create mode 100644 libc/include/llvm-libc-types/__qsortscompare_t.h
create mode 100644 libc/src/stdlib/qsort_s.cpp
create mode 100644 libc/src/stdlib/qsort_s.h
create mode 100644 libc/test/src/stdlib/qsort_s_test.cpp
diff --git a/libc/config/baremetal/aarch64/entrypoints.txt b/libc/config/baremetal/aarch64/entrypoints.txt
index dcb50135232e2..d7dacdedb479e 100644
--- a/libc/config/baremetal/aarch64/entrypoints.txt
+++ b/libc/config/baremetal/aarch64/entrypoints.txt
@@ -257,6 +257,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.stdlib.memalignment
libc.src.stdlib.qsort
libc.src.stdlib.qsort_r
+ libc.src.stdlib.qsort_s
libc.src.stdlib.rand
libc.src.stdlib.realloc
libc.src.stdlib.srand
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
index fac62bac939cc..29e58cb4d24ab 100644
--- a/libc/config/baremetal/arm/entrypoints.txt
+++ b/libc/config/baremetal/arm/entrypoints.txt
@@ -257,6 +257,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.stdlib.memalignment
libc.src.stdlib.qsort
libc.src.stdlib.qsort_r
+ libc.src.stdlib.qsort_s
libc.src.stdlib.rand
libc.src.stdlib.realloc
libc.src.stdlib.srand
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 35f91c18f4bfb..7047cc6c3e853 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -196,6 +196,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.stdlib.memalignment
libc.src.stdlib.qsort
libc.src.stdlib.qsort_r
+ libc.src.stdlib.qsort_s
libc.src.stdlib.rand
libc.src.stdlib.srand
libc.src.stdlib.strfromd
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index eda0426ff2578..5cc74378b3c26 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -208,6 +208,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.stdlib.memalignment
libc.src.stdlib.qsort
libc.src.stdlib.qsort_r
+ libc.src.stdlib.qsort_s
libc.src.stdlib.rand
libc.src.stdlib.srand
libc.src.stdlib.strfromd
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index 6a02241b7d6a2..241639e9a95bf 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -434,6 +434,7 @@ add_header_macro(
.llvm-libc-types.__atexithandler_t
.llvm-libc-types.__qsortcompare_t
.llvm-libc-types.__qsortrcompare_t
+ .llvm-libc-types.__qsortscompare_t
.llvm-libc-types.__search_compare_t
.llvm-libc-types.constraint_handler_t
.llvm-libc-types.div_t
diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
index 2904e0d07f76c..519a714c81406 100644
--- a/libc/include/llvm-libc-types/CMakeLists.txt
+++ b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -24,6 +24,7 @@ add_header(__pthread_start_t HDR __pthread_start_t.h)
add_header(__pthread_tss_dtor_t HDR __pthread_tss_dtor_t.h)
add_header(__qsortcompare_t HDR __qsortcompare_t.h)
add_header(__qsortrcompare_t HDR __qsortrcompare_t.h)
+add_header(__qsortscompare_t HDR __qsortscompare_t.h)
add_header(__thread_type HDR __thread_type.h)
add_header(blkcnt_t HDR blkcnt_t.h)
add_header(blksize_t HDR blksize_t.h)
diff --git a/libc/include/llvm-libc-types/__qsortscompare_t.h b/libc/include/llvm-libc-types/__qsortscompare_t.h
new file mode 100644
index 0000000000000..8f88687bb1de5
--- /dev/null
+++ b/libc/include/llvm-libc-types/__qsortscompare_t.h
@@ -0,0 +1,14 @@
+//===-- Definition of type __qsortscompare_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___QSORTSCOMPARE_T_H
+#define LLVM_LIBC_TYPES___QSORTSCOMPARE_T_H
+
+typedef int (*__qsortscompare_t)(const void *, const void *, void *);
+
+#endif // LLVM_LIBC_TYPES___QSORTSCOMPARE_T_H
diff --git a/libc/include/stdlib.yaml b/libc/include/stdlib.yaml
index 4c958cd9d28ad..25c898c33e09d 100644
--- a/libc/include/stdlib.yaml
+++ b/libc/include/stdlib.yaml
@@ -14,6 +14,8 @@ types:
- type_name: __atexithandler_t
- type_name: __qsortcompare_t
- type_name: __qsortrcompare_t
+ - type_name: __qsortscompare_t
+ guard: LIBC_HAS_ANNEX_K
- type_name: __search_compare_t
- type_name: constraint_handler_t
- type_name: div_t
@@ -191,6 +193,17 @@ functions:
- type: size_t
- type: __qsortrcompare_t
- type: void *
+ - name: qsort_s
+ standards:
+ - stdc
+ return_type: errno_t
+ arguments:
+ - type: void *
+ - type: rsize_t
+ - type: rsize_t
+ - type: __qsortscompare_t
+ - type: void *
+ guard: LIBC_HAS_ANNEX_K
- name: quick_exit
standards:
- stdc
diff --git a/libc/src/stdlib/CMakeLists.txt b/libc/src/stdlib/CMakeLists.txt
index 16c9874f01017..8e5ebdec96196 100644
--- a/libc/src/stdlib/CMakeLists.txt
+++ b/libc/src/stdlib/CMakeLists.txt
@@ -356,6 +356,22 @@ add_entrypoint_object(
libc.hdr.types.size_t
)
+add_entrypoint_object(
+ qsort_s
+ SRCS
+ qsort_s.cpp
+ HDRS
+ qsort_s.h
+ DEPENDS
+ .qsort_util
+ libc.hdr.stdint_proxy
+ libc.hdr.types.errno_t
+ libc.hdr.types.rsize_t
+ libc.src.__support.common
+ libc.src.__support.constraint_handler
+ libc.src.__support.macros.config
+)
+
add_object_library(
rand_util
SRCS
diff --git a/libc/src/stdlib/qsort_s.cpp b/libc/src/stdlib/qsort_s.cpp
new file mode 100644
index 0000000000000..bd7480a86b487
--- /dev/null
+++ b/libc/src/stdlib/qsort_s.cpp
@@ -0,0 +1,47 @@
+//===-- Implementation of qsort -------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdlib/qsort_s.h"
+#define __STDC_WANT_LIB_EXT1__ 1
+#include "hdr/stdint_proxy.h"
+#undef __STDC_WANT_LIB_EXT1__
+#include "src/__support/common.h"
+#include "src/__support/constraint_handler.h"
+#include "src/__support/macros/config.h"
+#include "src/stdlib/qsort_util.h"
+
+#define ERRNO_T_FAIL 1
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(errno_t, qsort_s,
+ (void *array, rsize_t array_size, rsize_t elem_size,
+ int (*compare)(const void *, const void *, void *),
+ void *context)) {
+ const char *constraint_violation_msg = 0;
+ if (array_size > RSIZE_MAX) {
+ constraint_violation_msg =
+ "qsort_s: array_size cannot be greater than RSIZE_MAX";
+ } else if (elem_size > RSIZE_MAX) {
+ constraint_violation_msg =
+ "qsort_s: elem_size cannot be greater than RSIZE_MAX";
+ } else if ((array_size != 0) && (array == 0 || compare == 0)) {
+ constraint_violation_msg =
+ "qsort_s: if array_size is not equal to zero, then neither array nor "
+ "compare can be a null pointer";
+ }
+ if (constraint_violation_msg) {
+ libc_global_constraint_handler(constraint_violation_msg, 0, ERRNO_T_FAIL);
+ return ERRNO_T_FAIL;
+ }
+
+ internal::unstable_sort(array, array_size, elem_size, compare, context);
+ return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/qsort_s.h b/libc/src/stdlib/qsort_s.h
new file mode 100644
index 0000000000000..74ac2f9e49c7a
--- /dev/null
+++ b/libc/src/stdlib/qsort_s.h
@@ -0,0 +1,24 @@
+//===-- Implementation header for qsort_s------------------------*- C++ -*-===//
+//
+// 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_SRC_STDLIB_QSORT_S_H
+#define LLVM_LIBC_SRC_STDLIB_QSORT_S_H
+
+#include "hdr/types/errno_t.h"
+#include "hdr/types/rsize_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+errno_t qsort_s(void *array, rsize_t array_size, rsize_t elem_size,
+ int (*compare)(const void *, const void *, void *),
+ void *context);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_STDLIB_QSORT_H
diff --git a/libc/test/src/stdlib/CMakeLists.txt b/libc/test/src/stdlib/CMakeLists.txt
index 270a7a2291293..d7b60bbe3344a 100644
--- a/libc/test/src/stdlib/CMakeLists.txt
+++ b/libc/test/src/stdlib/CMakeLists.txt
@@ -366,6 +366,22 @@ add_libc_test(
libc.src.stdlib.qsort_r
)
+add_libc_test(
+ qsort_s_test
+ SUITE
+ libc-stdlib-tests
+ SRCS
+ qsort_s_test.cpp
+ HDRS
+ QsortReentrantTest.h
+ DEPENDS
+ libc.hdr.stdint_proxy
+ libc.hdr.types.errno_t
+ libc.hdr.types.rsize_t
+ libc.src.stdlib.qsort_s
+ libc.test.UnitTest.ConstraintHandlerCheckingTest
+)
+
add_libc_test(
rand_test
SUITE
diff --git a/libc/test/src/stdlib/qsort_s_test.cpp b/libc/test/src/stdlib/qsort_s_test.cpp
new file mode 100644
index 0000000000000..798e9827077c2
--- /dev/null
+++ b/libc/test/src/stdlib/qsort_s_test.cpp
@@ -0,0 +1,68 @@
+//===-- Unittests for qsort_s ---------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#define __STDC_WANT_LIB_EXT1__ 1
+#include "QsortReentrantTest.h"
+#include "hdr/stdint_proxy.h"
+#include "hdr/types/errno_t.h"
+#include "hdr/types/rsize_t.h"
+#include "src/stdlib/qsort_s.h"
+#include "test/UnitTest/ConstraintHandlerCheckingTest.h"
+#include "test/UnitTest/Test.h"
+
+QSORTREENTRANT_TEST(QsortS, LIBC_NAMESPACE::qsort_s, rsize_t)
+
+using LlvmLibcQsortSConstraintTest =
+ LIBC_NAMESPACE::testing::ConstraintHandlerCheckingTest;
+
+static int compare(const void *a, const void *b, void *) {
+ const int *a_int = static_cast<const int *>(a);
+ const int *b_int = static_cast<const int *>(b);
+ return *a_int - *b_int;
+}
+
+TEST_F(LlvmLibcQsortSConstraintTest, ArraySizeGreaterThanRsizeMax) {
+ int array[] = {1, 3, 2};
+ errno_t retval =
+ LIBC_NAMESPACE::qsort_s(array, RSIZE_MAX + 1, sizeof(int), compare, 0);
+ EXPECT_NE(retval, 0);
+ EXPECT_STREQ(buffer, "qsort_s: array_size cannot be greater than RSIZE_MAX");
+ EXPECT_EQ(array[0], 1);
+ EXPECT_EQ(array[1], 3);
+ EXPECT_EQ(array[2], 2);
+}
+
+TEST_F(LlvmLibcQsortSConstraintTest, ElemSizeGreaterThanRsizeMax) {
+ int array[] = {1, 3, 2};
+ errno_t retval = LIBC_NAMESPACE::qsort_s(array, sizeof(array) / sizeof(int),
+ RSIZE_MAX + 1, compare, 0);
+ EXPECT_NE(retval, 0);
+ EXPECT_STREQ(buffer, "qsort_s: elem_size cannot be greater than RSIZE_MAX");
+ EXPECT_EQ(array[0], 1);
+ EXPECT_EQ(array[1], 3);
+ EXPECT_EQ(array[2], 2);
+}
+
+TEST_F(LlvmLibcQsortSConstraintTest, ArrayPointerIsNull) {
+ errno_t retval = LIBC_NAMESPACE::qsort_s(0, 5, sizeof(int), compare, 0);
+ EXPECT_NE(retval, 0);
+ EXPECT_STREQ(buffer, "qsort_s: if array_size is not equal to zero, then "
+ "neither array nor compare can be a null pointer");
+}
+
+TEST_F(LlvmLibcQsortSConstraintTest, ComparePointerIsNull) {
+ int array[] = {1, 3, 2};
+ errno_t retval = LIBC_NAMESPACE::qsort_s(array, sizeof(array) / sizeof(int),
+ sizeof(int), 0, 0);
+ EXPECT_NE(retval, 0);
+ EXPECT_STREQ(buffer, "qsort_s: if array_size is not equal to zero, then "
+ "neither array nor compare can be a null pointer");
+ EXPECT_EQ(array[0], 1);
+ EXPECT_EQ(array[1], 3);
+ EXPECT_EQ(array[2], 2);
+}
>From 9698d0bd7b48afdc8f8a34ce94b07fcdd13f9caa Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Fri, 19 Jun 2026 17:08:33 +0100
Subject: [PATCH 4/5] Address comments
---
libc/src/stdlib/qsort_s.cpp | 13 ++++++++-----
libc/src/stdlib/qsort_s.h | 9 +++++++--
libc/test/src/stdlib/qsort_s_test.cpp | 21 ++++++++++++++-------
3 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/libc/src/stdlib/qsort_s.cpp b/libc/src/stdlib/qsort_s.cpp
index bd7480a86b487..695f687eab420 100644
--- a/libc/src/stdlib/qsort_s.cpp
+++ b/libc/src/stdlib/qsort_s.cpp
@@ -1,10 +1,15 @@
-//===-- Implementation of qsort -------------------------------------------===//
+//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the implementation of qsort_s.
+///
+//===----------------------------------------------------------------------===//
#include "src/stdlib/qsort_s.h"
#define __STDC_WANT_LIB_EXT1__ 1
@@ -15,8 +20,6 @@
#include "src/__support/macros/config.h"
#include "src/stdlib/qsort_util.h"
-#define ERRNO_T_FAIL 1
-
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(errno_t, qsort_s,
@@ -36,8 +39,8 @@ LLVM_LIBC_FUNCTION(errno_t, qsort_s,
"compare can be a null pointer";
}
if (constraint_violation_msg) {
- libc_global_constraint_handler(constraint_violation_msg, 0, ERRNO_T_FAIL);
- return ERRNO_T_FAIL;
+ libc_global_constraint_handler(constraint_violation_msg, 0, 1);
+ return 1;
}
internal::unstable_sort(array, array_size, elem_size, compare, context);
diff --git a/libc/src/stdlib/qsort_s.h b/libc/src/stdlib/qsort_s.h
index 74ac2f9e49c7a..a01bc29061ef4 100644
--- a/libc/src/stdlib/qsort_s.h
+++ b/libc/src/stdlib/qsort_s.h
@@ -1,10 +1,15 @@
-//===-- Implementation header for qsort_s------------------------*- C++ -*-===//
+//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the implementation header for qsort_s.
+///
+//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STDLIB_QSORT_S_H
#define LLVM_LIBC_SRC_STDLIB_QSORT_S_H
@@ -21,4 +26,4 @@ errno_t qsort_s(void *array, rsize_t array_size, rsize_t elem_size,
} // namespace LIBC_NAMESPACE_DECL
-#endif // LLVM_LIBC_SRC_STDLIB_QSORT_H
+#endif // LLVM_LIBC_SRC_STDLIB_QSORT_S_H
diff --git a/libc/test/src/stdlib/qsort_s_test.cpp b/libc/test/src/stdlib/qsort_s_test.cpp
index 798e9827077c2..13370b7e7bb14 100644
--- a/libc/test/src/stdlib/qsort_s_test.cpp
+++ b/libc/test/src/stdlib/qsort_s_test.cpp
@@ -1,10 +1,15 @@
-//===-- Unittests for qsort_s ---------------------------------------------===//
+//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains unit tests for qsort_s.
+///
+//===----------------------------------------------------------------------===//
#define __STDC_WANT_LIB_EXT1__ 1
#include "QsortReentrantTest.h"
@@ -28,10 +33,11 @@ static int compare(const void *a, const void *b, void *) {
TEST_F(LlvmLibcQsortSConstraintTest, ArraySizeGreaterThanRsizeMax) {
int array[] = {1, 3, 2};
+ EXPECT_FALSE(error_flag);
errno_t retval =
LIBC_NAMESPACE::qsort_s(array, RSIZE_MAX + 1, sizeof(int), compare, 0);
EXPECT_NE(retval, 0);
- EXPECT_STREQ(buffer, "qsort_s: array_size cannot be greater than RSIZE_MAX");
+ EXPECT_TRUE(error_flag);
EXPECT_EQ(array[0], 1);
EXPECT_EQ(array[1], 3);
EXPECT_EQ(array[2], 2);
@@ -39,29 +45,30 @@ TEST_F(LlvmLibcQsortSConstraintTest, ArraySizeGreaterThanRsizeMax) {
TEST_F(LlvmLibcQsortSConstraintTest, ElemSizeGreaterThanRsizeMax) {
int array[] = {1, 3, 2};
+ EXPECT_FALSE(error_flag);
errno_t retval = LIBC_NAMESPACE::qsort_s(array, sizeof(array) / sizeof(int),
RSIZE_MAX + 1, compare, 0);
EXPECT_NE(retval, 0);
- EXPECT_STREQ(buffer, "qsort_s: elem_size cannot be greater than RSIZE_MAX");
+ EXPECT_TRUE(error_flag);
EXPECT_EQ(array[0], 1);
EXPECT_EQ(array[1], 3);
EXPECT_EQ(array[2], 2);
}
TEST_F(LlvmLibcQsortSConstraintTest, ArrayPointerIsNull) {
+ EXPECT_FALSE(error_flag);
errno_t retval = LIBC_NAMESPACE::qsort_s(0, 5, sizeof(int), compare, 0);
EXPECT_NE(retval, 0);
- EXPECT_STREQ(buffer, "qsort_s: if array_size is not equal to zero, then "
- "neither array nor compare can be a null pointer");
+ EXPECT_TRUE(error_flag);
}
TEST_F(LlvmLibcQsortSConstraintTest, ComparePointerIsNull) {
int array[] = {1, 3, 2};
+ EXPECT_FALSE(error_flag);
errno_t retval = LIBC_NAMESPACE::qsort_s(array, sizeof(array) / sizeof(int),
sizeof(int), 0, 0);
EXPECT_NE(retval, 0);
- EXPECT_STREQ(buffer, "qsort_s: if array_size is not equal to zero, then "
- "neither array nor compare can be a null pointer");
+ EXPECT_TRUE(error_flag);
EXPECT_EQ(array[0], 1);
EXPECT_EQ(array[1], 3);
EXPECT_EQ(array[2], 2);
>From eb6ccba73ab9ea07e1cf3c1747fec731ecaf4f63 Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Fri, 26 Jun 2026 18:02:28 +0100
Subject: [PATCH 5/5] Fix file header to adhere to the coding standard
---
libc/test/src/stdlib/QsortReentrantTest.h | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/libc/test/src/stdlib/QsortReentrantTest.h b/libc/test/src/stdlib/QsortReentrantTest.h
index 4453a27b01f38..0f80478e548c3 100644
--- a/libc/test/src/stdlib/QsortReentrantTest.h
+++ b/libc/test/src/stdlib/QsortReentrantTest.h
@@ -1,11 +1,15 @@
-
-//===-- A template class for testing reentrant qsort functions --*- C++ -*-===//
+//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains a test template for reentrant qsort functions.
+///
+//===----------------------------------------------------------------------===//
#include "test/UnitTest/Test.h"
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