https://gcc.gnu.org/g:479446beb4d212c19fe6b12d22a5dc6593798c47
commit r16-2669-g479446beb4d212c19fe6b12d22a5dc6593798c47
Author: Yury Khrustalev <yury.khrusta...@arm.com>
Date: Tue Jul 22 15:50:03 2025 +0100
testsuite: Add runtime test for FMV resolvers
gcc/testsuite/ChangeLog:
* g++.target/aarch64/mv-cpu-features.C: new test.
Diff:
---
gcc/testsuite/g++.target/aarch64/mv-cpu-features.C | 82 ++++++++++++++++++++++
1 file changed, 82 insertions(+)
diff --git a/gcc/testsuite/g++.target/aarch64/mv-cpu-features.C
b/gcc/testsuite/g++.target/aarch64/mv-cpu-features.C
new file mode 100644
index 000000000000..ad6accd4c630
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/mv-cpu-features.C
@@ -0,0 +1,82 @@
+/* { dg-do run } */
+/* { dg-require-ifunc "" } */
+/* { dg-require-effective-target mmap } */
+/* { dg-options "-Wno-experimental-fmv-target" } */
+
+#include <cstdint>
+#include <sys/auxv.h>
+
+__attribute__((target_version ("default")))
+int foo ()
+{
+ return 0;
+}
+
+__attribute__((target_version ("rng")))
+int foo ()
+{
+ return 1;
+}
+
+__attribute__((target_version ("lse")))
+int foo ()
+{
+ return 2;
+}
+
+typedef struct {
+ uint64_t size;
+ uint64_t hwcap;
+ uint64_t hwcap2;
+ uint64_t hwcap3;
+ uint64_t hwcap4;
+} ifunc_arg_t;
+
+int impl ()
+{
+ return 0;
+}
+
+#ifndef _IFUNC_ARG_HWCAP
+#define _IFUNC_ARG_HWCAP (1ULL << 62)
+#endif
+
+extern "C" void
+__init_cpu_features_resolver (unsigned long hwcap, const ifunc_arg_t *arg);
+
+extern "C" void *
+fun_resolver (uint64_t a0, const ifunc_arg_t *a1)
+{
+ ifunc_arg_t arg = {};
+ arg.size = sizeof (ifunc_arg_t);
+ /* These flags determine that the implementation of foo ()
+ that returns 2 will be selected. */
+ arg.hwcap = HWCAP_ATOMICS;
+ arg.hwcap2 = HWCAP2_RNG;
+ __init_cpu_features_resolver (arg.hwcap | _IFUNC_ARG_HWCAP, &arg);
+ return (void *)(uintptr_t)impl;
+}
+
+extern "C" int fun (void) __attribute__((ifunc ("fun_resolver")));
+
+/* In this test we expect that the manual resolver for the fun ()
+ function will be executed before the automatic resolver for the
+ FMV function foo (). This is because resolvers from the same TU
+ are executed according to the offset of corresponding relocations.
+
+ Automatic resolver is generated in a dedicated section while the
+ manually written resolver will be put in the .text section which
+ will come first.
+
+ The manual resolver above calls __init_cpu_features_resolver()
+ supplying synthetic ifunc_arg_t fields that will determine the
+ choice for the FMV implementation.
+ */
+
+int main ()
+{
+ int res = fun ();
+ if (res == 0 && foo () == 2)
+ return 0;
+ return 1;
+}
