llvm-project

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// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// REQUIRES: linux && target={{aarch64-.+}}
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// Basic test for float registers number are accepted.
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#include <stdlib.h>
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#include <string.h>
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#include <unwind.h>
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// Using __attribute__((section("main_func"))) is ELF specific, but then
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// this entire test is marked as requiring Linux, so we should be good.
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//
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// We don't use dladdr() because on musl it's a no-op when statically linked.
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extern char __start_main_func;
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extern char __stop_main_func;
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_Unwind_Reason_Code frame_handler(struct _Unwind_Context *ctx, void *arg) {
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  (void)arg;
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  // Unwind until the main is reached, above frames depend on the platform and
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  // architecture.
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  uintptr_t ip = _Unwind_GetIP(ctx);
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  if (ip >= (uintptr_t)&__start_main_func &&
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      ip < (uintptr_t)&__stop_main_func) {
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    _Exit(0);
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  }
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  return _URC_NO_REASON;
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}
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__attribute__((noinline)) void foo() {
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  // Provide some CFI directives that instructs the unwinder where given
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  // float register is.
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#if defined(__aarch64__)
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  // DWARF register number for V0-V31 registers are 64-95.
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  // Previous value of V0 is saved at offset 0 from CFA.
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  asm volatile(".cfi_offset 64, 0");
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  // From now on the previous value of register can't be restored anymore.
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  asm volatile(".cfi_undefined 65");
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  asm volatile(".cfi_undefined 95");
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  // Previous value of V2 is in V30.
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  asm volatile(".cfi_register  66, 94");
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#endif
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  _Unwind_Backtrace(frame_handler, NULL);
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}
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__attribute__((section("main_func"))) int main() {
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  foo();
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  return -2;
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}
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