gdb/testsuite/gdb.dwarf2/nonvar-access.exp

# Copyright 2016-2021 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 accessing "non-variable" variables, i.e., variables which are
# optimized to a constant DWARF location expression and/or
# partially/fully optimized out.

load_lib dwarf.exp

if {![dwarf2_support]} { return 0 }

standard_testfile main.c -dw.S

# Make some DWARF for the test.
set asm_file [standard_output_file $srcfile2]

Dwarf::assemble $asm_file {
    global srcfile

    cu {} {
	compile_unit {
	    {DW_AT_name $srcfile}
	} {
	    declare_labels int_type_label char_type_label \
		struct_s_label struct_t_label array_a9_label \
		char_ptr_label implicit_a_label stack_b_label

	    int_type_label: base_type {
		{name "int"}
		{encoding @DW_ATE_signed}
		{byte_size 4 DW_FORM_sdata}
	    }
	    char_type_label: base_type {
		{name "char"}
		{encoding @DW_ATE_unsigned}
		{byte_size 1 DW_FORM_sdata}
	    }
	    char_ptr_label: pointer_type {
		{type :$char_type_label}
	    }

	    struct_s_label: structure_type {
		{name s}
		{byte_size 4 DW_FORM_sdata}
	    } {
		member {
		    {name a}
		    {type :$int_type_label}
		    {data_member_location 0 DW_FORM_udata}
		    {bit_size 8 DW_FORM_udata}
		}
		member {
		    {name b}
		    {type :$int_type_label}
		    {data_bit_offset 8 DW_FORM_udata}
		    {bit_size 24 DW_FORM_udata}
		}
	    }

	    struct_t_label: structure_type {
		{name t}
		{byte_size 4 DW_FORM_sdata}
	    } {
		member {
		    {name a}
		    {type :$int_type_label}
		    {data_member_location 0 DW_FORM_udata}
		    {bit_size 9 DW_FORM_udata}
		}
		member {
		    {name b}
		    {type :$int_type_label}
		    {data_bit_offset 9 DW_FORM_udata}
		    {bit_size 23 DW_FORM_udata}
		}
	    }

	    array_a9_label: array_type {
		{type :$char_type_label}
	    } {
		subrange_type {
		    {type :$int_type_label}
		    {upper_bound 8 DW_FORM_udata}
		}
	    }

	    DW_TAG_subprogram {
		{MACRO_AT_func {main}}
		{DW_AT_external 1 flag}
	    } {
		# Simple variable without location.
		DW_TAG_variable {
		    {name undef_int}
		    {type :$int_type_label}
		}
		# Struct variable without location.
		DW_TAG_variable {
		    {name undef_s}
		    {type :$struct_s_label}
		}
		# Composite location: byte-aligned pieces.
		DW_TAG_variable {
		    {name def_s}
		    {type :$struct_s_label}
		    {location {
			const1u 0
			stack_value
			bit_piece 8 0
			const1s -1
			stack_value
			bit_piece 24 0
		    } SPECIAL_expr}
		}
		# Composite location: non-byte-aligned pieces.
		DW_TAG_variable {
		    {name def_t}
		    {type :$struct_t_label}
		    {location {
			const2s -184
			stack_value
			bit_piece 9 0
			const4u 1752286
			stack_value
			bit_piece 23 0
		    } SPECIAL_expr}
		}
		# Composite location with some empty pieces.
		DW_TAG_variable {
		    {name part_def_a}
		    {type :$array_a9_label}
		    {location {
			piece 3
			const4u 0xf1927314
			stack_value
			piece 4
			piece 2
		    } SPECIAL_expr}
		}
		# Implicit location: immediate value.
		DW_TAG_variable {
		    {name def_implicit_s}
		    {type :$struct_s_label}
		    {location {
			implicit_value 0x12 0x34 0x56 0x78
		    } SPECIAL_expr}
		}
		# Implicit location: immediate value for whole array, with
		# excess bytes.
		implicit_a_label: DW_TAG_variable {
		    {name def_implicit_a}
		    {type :$array_a9_label}
		    {location {
			implicit_value 0x1 0x12 0x23 0x34 0x45 \
			    0x56 0x67 0x78 0x89 0x9a 0xab
		    } SPECIAL_expr}
		}
		# Implicit pointer into immediate value.
		DW_TAG_variable {
		    {name implicit_a_ptr}
		    {type :$char_ptr_label}
		    {location {
			implicit_pointer $implicit_a_label 5
		    } SPECIAL_expr}
		}
		# Stack-value location.
		stack_b_label: DW_TAG_variable {
		    {name def_stack_b}
		    {type :$struct_t_label}
		    {location {
			const4u 0x1a2b3c4d
			stack_value
		    } SPECIAL_expr}
		}
		# Implicit pointer into stack value.
		DW_TAG_variable {
		    {name implicit_b_ptr}
		    {type :$char_ptr_label}
		    {location {
			implicit_pointer $stack_b_label 1
		    } SPECIAL_expr}
		}
	    }
	}
    }
}

if { [prepare_for_testing "failed to prepare" ${testfile} \
	  [list $srcfile $asm_file] {nodebug}] } {
    return -1
}

if ![runto_main] {
    return -1
}

# Determine byte order.
set endian [get_endianness]

# Byte-aligned objects with simple location descriptions.
switch $endian { big {set val 0x345678} little {set val 0x785634} }
gdb_test "print/x def_implicit_s" " = \\{a = 0x12, b = $val\\}"
gdb_test "print/x def_implicit_s.b" " = $val"
gdb_test "print/x def_implicit_a" \
    " = \\{0x1, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 0x89\\}"
gdb_test "print/x def_implicit_a\[5\]" " = 0x56"
gdb_test "print/x *(char (*)\[5\]) implicit_a_ptr" \
    " = \\{0x56, 0x67, 0x78, 0x89, 0x9a\\}"
switch $endian {
    big {set val "a = 52, b = 2833485"}
    little {set val "a = 77, b = 857502"}
}
gdb_test "print def_stack_b" " = \\{$val\\}"
switch $endian {big {set val 0x2b} little {set val 0x3c}}
gdb_test "print/x *implicit_b_ptr" " = $val"

# Byte-aligned fields, pieced together from DWARF stack values.
gdb_test "print def_s" " = \\{a = 0, b = -1\\}"
switch $endian { big {set val 0x92} little {set val 0x73} }
gdb_test "print/x part_def_a\[4\]" " = $val"
gdb_test "print/x part_def_a\[8\]" " = <optimized out>"

# Non-byte-aligned fields, pieced together from DWARF stack values.
gdb_test "print def_t" " = \\{a = -184, b = 1752286\\}"

# Simple variable without location.
gdb_test "print undef_int" " = <optimized out>"

# Member of a structure without location.
gdb_test "print undef_s.a" " = <optimized out>"