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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// REQUIRES: linux && target={{riscv64-.+}}
#undef NDEBUG
#include <assert.h>
#include <libunwind.h>
// Check correct unwinding of frame with VLENB-sized objects (vector registers):
// 1. Save return address (ra) in temporary register.
// 2. Load VLENB (vector length in bytes) and substract it from current stack
// pointer (sp) - equivalent to one vector register on stack frame.
// 3. Set DWARF cannonical frame address (CFA) to "sp + vlenb" expresssion so it
// can be correctly unwinded.
// 4. Call stepper() function and check that 2 unwind steps are successful -
// from stepper() into foo() and from foo() into main().
// 5. Restore stack pointer and return address.
__attribute__((naked)) static void foo() {
__asm__(".cfi_startproc\n"
"mv s0, ra\n"
"csrr s1, vlenb\n"
"sub sp, sp, s1\n"
"# .cfi_def_cfa_expression sp + vlenb\n"
".cfi_escape 0x0f, 0x07, 0x72, 0x00, 0x92, 0xa2, 0x38, 0x00, 0x22\n"
"call stepper\n"
"add sp, sp, s1\n"
"mv ra, s0\n"
"ret\n"
".cfi_endproc\n");
}
extern "C" void stepper() {
unw_cursor_t cursor;
unw_context_t uc;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
// Stepping into foo() should succeed.
assert(unw_step(&cursor) > 0);
// Stepping past foo() should succeed, too.
assert(unw_step(&cursor) > 0);
}
int main() { foo(); }
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