llvm-project
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1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10// REQUIRES: linux && target={{aarch64-.+}}
11
12// Basic test for float registers number are accepted.
13
14#include <stdlib.h>
15#include <string.h>
16#include <unwind.h>
17
18// Using __attribute__((section("main_func"))) is ELF specific, but then
19// this entire test is marked as requiring Linux, so we should be good.
20//
21// We don't use dladdr() because on musl it's a no-op when statically linked.
22extern char __start_main_func;
23extern char __stop_main_func;
24
25_Unwind_Reason_Code frame_handler(struct _Unwind_Context *ctx, void *arg) {
26(void)arg;
27
28// Unwind until the main is reached, above frames depend on the platform and
29// architecture.
30uintptr_t ip = _Unwind_GetIP(ctx);
31if (ip >= (uintptr_t)&__start_main_func &&
32ip < (uintptr_t)&__stop_main_func) {
33_Exit(0);
34}
35
36return _URC_NO_REASON;
37}
38
39__attribute__((noinline)) void foo() {
40// Provide some CFI directives that instructs the unwinder where given
41// float register is.
42#if defined(__aarch64__)
43// DWARF register number for V0-V31 registers are 64-95.
44// Previous value of V0 is saved at offset 0 from CFA.
45asm volatile(".cfi_offset 64, 0");
46// From now on the previous value of register can't be restored anymore.
47asm volatile(".cfi_undefined 65");
48asm volatile(".cfi_undefined 95");
49// Previous value of V2 is in V30.
50asm volatile(".cfi_register 66, 94");
51#endif
52_Unwind_Backtrace(frame_handler, NULL);
53}
54
55__attribute__((section("main_func"))) int main() {
56foo();
57return -2;
58}
59