| # 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 a C++ reference marked with DW_OP_GNU_implicit_pointer. |
| # The referenced value is a DW_AT_const_value. |
| |
| if [skip_cplus_tests] { |
| continue |
| } |
| |
| load_lib dwarf.exp |
| |
| # This test can only be run on targets which support DWARF-2 and use gas. |
| if ![dwarf2_support] { |
| return 0 |
| } |
| |
| # We'll place the output of Dwarf::assemble in implref-const.S. |
| standard_testfile main.c .S |
| |
| # ${testfile} is now "implref-const". srcfile2 is "implref-const.S". |
| set executable ${testfile} |
| set asm_file [standard_output_file ${srcfile2}] |
| |
| # We need to know the size of integer and address types in order |
| # to write some of the debugging info we'd like to generate. |
| # |
| # For that, we ask GDB by debugging our implref-const program. |
| # Any program would do, but since we already have implref-const |
| # specifically for this testcase, might as well use that. |
| if [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] { |
| return -1 |
| } |
| |
| # Create the DWARF. We need a regular variable and a reference to it that'll |
| # be marked with DW_OP_GNU_implicit_pointer. |
| Dwarf::assemble ${asm_file} { |
| cu {} { |
| DW_TAG_compile_unit { |
| {DW_AT_language @DW_LANG_C_plus_plus} |
| } { |
| declare_labels int_label const_label variable_label ref_label |
| set int_size [get_sizeof "int" -1] |
| |
| # gdb always assumes references are implemented as pointers. |
| set addr_size [get_sizeof "void *" -1] |
| set var_value 42 |
| |
| int_label: DW_TAG_base_type { |
| {DW_AT_byte_size ${int_size} DW_FORM_udata} |
| {DW_AT_encoding @DW_ATE_signed} |
| {DW_AT_name "int"} |
| } |
| |
| ref_label: DW_TAG_reference_type { |
| {DW_AT_byte_size ${addr_size} DW_FORM_udata} |
| {DW_AT_type :${int_label}} |
| } |
| |
| const_label: DW_TAG_const_type { |
| {DW_AT_type :${ref_label}} |
| } |
| |
| DW_TAG_subprogram { |
| {MACRO_AT_func { "main" }} |
| {DW_AT_type :${int_label}} |
| {DW_AT_external 1 DW_FORM_flag} |
| } { |
| variable_label: DW_TAG_variable { |
| {DW_AT_name "var"} |
| {DW_AT_type :${int_label}} |
| {DW_AT_const_value ${var_value} DW_FORM_udata} |
| } |
| |
| DW_TAG_variable { |
| {DW_AT_name "ref"} |
| {DW_AT_type :${const_label}} |
| {DW_AT_location {DW_OP_GNU_implicit_pointer ${variable_label} 0} SPECIAL_expr} |
| } |
| } |
| } |
| } |
| } |
| |
| if [prepare_for_testing "failed to prepare" ${executable} [list ${asm_file} ${srcfile}] {}] { |
| return -1 |
| } |
| |
| # DW_OP_GNU_implicit_pointer implementation requires a valid frame. |
| if ![runto_main] { |
| return -1 |
| } |
| |
| # Doing 'print ref' should show us e.g. '(int &) <synthetic pointer>: 42'. |
| gdb_test "print ref" " = \\(int &\\) <synthetic pointer>: \\\d+" |
| |
| # The variable isn't located in memory, thus we can't take its address. |
| gdb_test "print &var" "Can't take address of \"var\" which isn't an lvalue." |
| gdb_test "print &ref" "Attempt to take address of value not located in memory." |
| |
| # gdb assumes C++ references are implemented as pointers, and print &(&ref) |
| # shows us the underlying pointer's address. |
| # Since in this case there's no physical pointer, gdb should tell us so. |
| gdb_test "print &(&ref)" "Attempt to take address of value not located in memory." |