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This enables better compiler optimization, particularly for Clang which can now recognize simple pointer patterns and apply vectorization, loop unrolling, and improved assembly. The implementation uses C11 _Generic to dispatch based on input type: - Integer types (int, uint64_t, etc.) continue using uintptr_t arithmetic for API compatibility - Pointer types use char* arithmetic, with const-qualified pointers using const char* internally to preserve optimization hints Example use case which benefits is __rte_raw_cksum. Performance results from cksum_perf_autotest on Intel Xeon (Cascade Lake, AVX-512) built with Clang 18.1 (TSC cycles/byte): Block size Before After Improvement 100 0.40 0.24 ~40% 1500 0.50 0.06 ~8x 9000 0.49 0.06 ~8x Signed-off-by: Scott Mitchell --- app/test/meson.build | 1 + app/test/test_ptr_add_sub.c | 190 +++++++++++++++++++++++++++++++++++ lib/eal/include/rte_common.h | 60 +++++++++++ 3 files changed, 251 insertions(+) create mode 100644 app/test/test_ptr_add_sub.c diff --git a/app/test/meson.build b/app/test/meson.build index efec42a6bf..80a19d65ba 100644 --- a/app/test/meson.build +++ b/app/test/meson.build @@ -152,6 +152,7 @@ source_file_deps = { 'test_power_intel_uncore.c': ['power', 'power_intel_uncore'], 'test_power_kvm_vm.c': ['power', 'power_kvm_vm'], 'test_prefetch.c': [], + 'test_ptr_add_sub.c': [], 'test_ptr_compress.c': ['ptr_compress'], 'test_rand_perf.c': [], 'test_rawdev.c': ['rawdev', 'bus_vdev', 'raw_skeleton'], diff --git a/app/test/test_ptr_add_sub.c b/app/test/test_ptr_add_sub.c new file mode 100644 index 0000000000..ef449ca9af --- /dev/null +++ b/app/test/test_ptr_add_sub.c @@ -0,0 +1,190 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright(c) 2026 Apple Inc. + */ + +#include "test.h" +#include +#include + +#include + +/* Test all C11 standard integer types */ +static int +test_ptr_add_sub_integer_types(void) +{ + unsigned long long ull = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ull, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned long long"); + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_SUB(ull, 100), 0x1000 - 100, + "RTE_PTR_SUB failed for unsigned long long"); + + long long ll = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ll, 100), 0x1064, + "RTE_PTR_ADD failed for long long"); + + unsigned long ul = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ul, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned long"); + + long l = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(l, 100), 0x1064, + "RTE_PTR_ADD failed for long"); + + unsigned int ui = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ui, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned int"); + + int i = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(i, 100), 0x1064, + "RTE_PTR_ADD failed for int"); + + unsigned short us = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(us, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned short"); + + short s = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(s, 100), 0x1064, + "RTE_PTR_ADD failed for short"); + + unsigned char uc = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(uc, 50), 150, + "RTE_PTR_ADD failed for unsigned char"); + + signed char sc = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(sc, 50), 150, + "RTE_PTR_ADD failed for signed char"); + + char c = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(c, 50), 150, + "RTE_PTR_ADD failed for char"); + + _Bool b = 1; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(b, 99), 100, + "RTE_PTR_ADD failed for _Bool"); + + bool b2 = true; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(b2, 99), 100, + "RTE_PTR_ADD failed for bool"); + + return 0; +} + +/* Test pointer types including const correctness */ +static int +test_ptr_add_sub_pointer_types(void) +{ + char buffer[256]; + void *result; + + /* Test void* and const void* */ + void *vp = buffer; + result = RTE_PTR_ADD(vp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for void*"); + result = RTE_PTR_SUB(vp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for void*"); + + const void *cvp = buffer; + result = RTE_PTR_ADD(cvp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for const void*"); + result = RTE_PTR_SUB(cvp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for const void*"); + + /* Test char* and const char* */ + char *cp = buffer; + result = RTE_PTR_ADD(cp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for char*"); + result = RTE_PTR_SUB(cp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for char*"); + + const char *ccp = buffer; + result = RTE_PTR_ADD(ccp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for const char*"); + result = RTE_PTR_SUB(ccp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for const char*"); + + /* Test uint32_t* and const uint32_t* */ + uint32_t *u32p = (uint32_t *)buffer; + result = RTE_PTR_ADD(u32p, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for uint32_t*"); + result = RTE_PTR_SUB(u32p, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for uint32_t*"); + + const uint32_t *cu32p = (const uint32_t *)buffer; + result = RTE_PTR_ADD(cu32p, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for const uint32_t*"); + result = RTE_PTR_SUB(cu32p, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for const uint32_t*"); + + /* Verify assigning to const pointer works (adding const is safe) */ + const void *result_const = RTE_PTR_ADD(cvp, 100); + TEST_ASSERT_EQUAL(result_const, (const void *)(buffer + 100), + "RTE_PTR_ADD failed when assigning to const void*"); + + return 0; +} + +/* Test that typedefs resolve to native types correctly */ +static int +test_ptr_add_sub_typedefs(void) +{ + uint64_t u64 = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u64, 100), 0x1064, + "RTE_PTR_ADD failed for uint64_t"); + + uint32_t u32 = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u32, 100), 0x1064, + "RTE_PTR_ADD failed for uint32_t"); + + uint16_t u16 = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u16, 100), 0x1064, + "RTE_PTR_ADD failed for uint16_t"); + + uint8_t u8 = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u8, 50), 150, + "RTE_PTR_ADD failed for uint8_t"); + + uintptr_t uptr = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(uptr, 100), 0x1064, + "RTE_PTR_ADD failed for uintptr_t"); + + size_t sz = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(sz, 100), 0x1064, + "RTE_PTR_ADD failed for size_t"); + + return 0; +} + +/* Main test function that runs all subtests */ +static int +test_ptr_add_sub(void) +{ + int ret; + + ret = test_ptr_add_sub_integer_types(); + if (ret != 0) + return ret; + + ret = test_ptr_add_sub_pointer_types(); + if (ret != 0) + return ret; + + ret = test_ptr_add_sub_typedefs(); + if (ret != 0) + return ret; + + return 0; +} + +REGISTER_FAST_TEST(ptr_add_sub_autotest, true, true, test_ptr_add_sub); diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h index 9e7d84f929..1ae239b43a 100644 --- a/lib/eal/include/rte_common.h +++ b/lib/eal/include/rte_common.h @@ -551,12 +551,72 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) /** * add a byte-value offset to a pointer */ +#ifndef RTE_TOOLCHAIN_MSVC +#define RTE_PTR_ADD(ptr, x) \ + (__extension__ ({ \ + /* Diagnostics suppressed for internal macro operations only. \ + * Compiler type-checks all _Generic branches even when unselected, \ + * triggering warnings with no external impact. */ \ + __rte_diagnostic_push \ + __rte_diagnostic_ignored_wcast_qual \ + /* Uses uintptr_t arithmetic for integer types (API compatibility), \ + * and char* arithmetic for pointer types (enables optimization). */ \ + __auto_type _ptr_result = _Generic((ptr), \ + unsigned long long: ((void *)((uintptr_t)(ptr) + (x))), \ + long long: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned long: ((void *)((uintptr_t)(ptr) + (x))), \ + long: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned int: ((void *)((uintptr_t)(ptr) + (x))), \ + int: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned short: ((void *)((uintptr_t)(ptr) + (x))), \ + short: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned char: ((void *)((uintptr_t)(ptr) + (x))), \ + signed char: ((void *)((uintptr_t)(ptr) + (x))), \ + char: ((void *)((uintptr_t)(ptr) + (x))), \ + _Bool: ((void *)((uintptr_t)(ptr) + (x))), \ + default: ((void *)((char *)(ptr) + (x))) \ + ); \ + __rte_diagnostic_pop \ + _ptr_result; \ + })) +#else #define RTE_PTR_ADD(ptr, x) ((void*)((uintptr_t)(ptr) + (x))) +#endif /** * subtract a byte-value offset from a pointer */ +#ifndef RTE_TOOLCHAIN_MSVC +#define RTE_PTR_SUB(ptr, x) \ + (__extension__ ({ \ + /* Diagnostics suppressed for internal macro operations only. \ + * Compiler type-checks all _Generic branches even when unselected, \ + * triggering warnings with no external impact. */ \ + __rte_diagnostic_push \ + __rte_diagnostic_ignored_wcast_qual \ + /* Uses uintptr_t arithmetic for integer types (API compatibility), \ + * and char* arithmetic for pointer types (enables optimization). */ \ + __auto_type _ptr_result = _Generic((ptr), \ + unsigned long long: ((void *)((uintptr_t)(ptr) - (x))), \ + long long: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned long: ((void *)((uintptr_t)(ptr) - (x))), \ + long: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned int: ((void *)((uintptr_t)(ptr) - (x))), \ + int: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned short: ((void *)((uintptr_t)(ptr) - (x))), \ + short: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned char: ((void *)((uintptr_t)(ptr) - (x))), \ + signed char: ((void *)((uintptr_t)(ptr) - (x))), \ + char: ((void *)((uintptr_t)(ptr) - (x))), \ + _Bool: ((void *)((uintptr_t)(ptr) - (x))), \ + default: ((void *)((char *)(ptr) - (x))) \ + ); \ + __rte_diagnostic_pop \ + _ptr_result; \ + })) +#else #define RTE_PTR_SUB(ptr, x) ((void *)((uintptr_t)(ptr) - (x))) +#endif /** * get the difference between two pointer values, i.e. how far apart -- 2.39.5 (Apple Git-154)