libunwind/test/floatregister.pass.cpp

   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 <dlfcn.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <unwind.h>
  18
  19 _Unwind_Reason_Code frame_handler(struct _Unwind_Context *ctx, void *arg) {
  20   (void)arg;
  21   Dl_info info = {0, 0, 0, 0};
  22
  23   // Unwind util the main is reached, above frames depend on the platform and
  24   // architecture.
  25   if (dladdr(reinterpret_cast<void *>(_Unwind_GetIP(ctx)), &info) &&
  26       info.dli_sname && !strcmp("main", info.dli_sname))
  27     _Exit(0);
  28
  29   return _URC_NO_REASON;
  30 }
  31
  32 __attribute__((noinline)) void foo() {
  33   // Provide some CFI directives that instructs the unwinder where given
  34   // float register is.
  35 #if defined(__aarch64__)
  36   // DWARF register number for V0-V31 registers are 64-95.
  37   // Previous value of V0 is saved at offset 0 from CFA.
  38   asm volatile(".cfi_offset 64, 0");
  39   // From now on the previous value of register can't be restored anymore.
  40   asm volatile(".cfi_undefined 65");
  41   asm volatile(".cfi_undefined 95");
  42   // Previous value of V2 is in V30.
  43   asm volatile(".cfi_register  66, 94");
  44 #endif
  45   _Unwind_Backtrace(frame_handler, NULL);
  46 }
  47
  48 int main() {
  49   foo();
  50   return -2;
  51 }