# Copyright 2026 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Test that GDB can unwind using a .debug_frame section generated by
# the DWARF assembler.
#
# This test is amd64-specific, but could be ported to other
# architectures if needed.

load_lib dwarf.exp

require dwarf2_support is_x86_64_m64_target

standard_testfile .S -dw.S

# AMD64 DWARF register numbers.
set rax 0
set rbp 6
set rsp 7
set r12 12
set r13 13
set r14 14
set rip 16

foreach_with_prefix is_64 { false true } {
    set asm_file [standard_output_file ${testfile}-${is_64}-dw.S]

    Dwarf::assemble $asm_file {
	frame {
	    declare_labels cie_label

	    cie_label: CIE {
		return_address_register $::rip
		data_alignment_factor -8
		is_64 $::is_64
	    } {
		DW_CFA_def_cfa $::rsp 8
		DW_CFA_offset $::rip 1
	    }

	    # FDE for main
	    FDE $cie_label main main_len {
		is_64 $::is_64
	    } {
		DW_CFA_set_loc main_after_push_rbp
		DW_CFA_def_cfa_offset 16
		DW_CFA_offset $::rbp 2
		DW_CFA_set_loc main_after_set_rbp
		DW_CFA_def_cfa_register $::rbp
	    }

	    # FDE for caller
	    FDE $cie_label caller caller_len {
		is_64 $::is_64
	    } {
		DW_CFA_set_loc caller_after_push_rbp
		DW_CFA_def_cfa_offset 16
		DW_CFA_offset $::rbp 2
		DW_CFA_set_loc caller_after_set_rbp
		DW_CFA_def_cfa_register $::rbp
	    }

	    # FDE for callee
	    FDE $cie_label callee callee_len {
		is_64 $::is_64
	    } {
		DW_CFA_set_loc callee_after_push_rbp
		DW_CFA_def_cfa_offset 16
		DW_CFA_offset $::rbp 2
		DW_CFA_set_loc callee_after_set_rbp
		DW_CFA_def_cfa_register $::rbp

		DW_CFA_set_loc callee_body
		DW_CFA_offset $::r12 3
		DW_CFA_register $::r13 $::rax

		# r14's value is computed by an arbitrary expression.
		DW_CFA_val_expression $::r14 {
		    DW_OP_constu 0x99aabbcc
		}
	    }
	}
    }

    if { [prepare_for_testing "failed to prepare" ${testfile}-${is_64} \
	      [list $srcfile $asm_file] {nodebug}] } {
	continue
    }

    # Stop in caller before the call, to capture rbp.
    if { ![runto caller_call_callee] } {
	continue
    }

    set caller_rbp [get_hexadecimal_valueof "\$rbp" "UNKNOWN"]

    # Stop inside callee.
    gdb_breakpoint callee_body
    gdb_continue_to_breakpoint "callee_body"

    # Verify backtrace shows the full call chain.
    gdb_test "bt" "#0.*callee.*\r\n#1.*caller.*\r\n#2.*main.*"

    # Select caller's frame and check saved registers.
    gdb_test "frame 1" "#1.*caller.*"

    # r12 was saved on the stack by callee.
    gdb_test "p/x \$r12" "= 0x11223344"

    # r13 was saved in rax by callee.
    gdb_test "p/x \$r13" "= 0x55667788"

    # r14's value is computed by a DWARF expression.
    gdb_test "p/x \$r14" "= 0x99aabbcc"

    # rbp should match what caller had.
    gdb_test "p/x \$rbp" "= ${caller_rbp}"
}