1# Copyright 2016-2020 Free Software Foundation, Inc. 2 3# This program is free software; you can redistribute it and/or modify 4# it under the terms of the GNU General Public License as published by 5# the Free Software Foundation; either version 3 of the License, or 6# (at your option) any later version. 7# 8# This program is distributed in the hope that it will be useful, 9# but WITHOUT ANY WARRANTY; without even the implied warranty of 10# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11# GNU General Public License for more details. 12# 13# You should have received a copy of the GNU General Public License 14# along with this program. If not, see <http://www.gnu.org/licenses/>. 15 16# Test a C++ reference marked with DW_OP_GNU_implicit_pointer. 17# The referenced value is a global variable whose location is a DW_OP_addr. 18 19if [skip_cplus_tests] { 20 continue 21} 22 23load_lib dwarf.exp 24 25# This test can only be run on targets which support DWARF-2 and use gas. 26if ![dwarf2_support] { 27 return 0 28} 29 30# We'll place the output of Dwarf::assemble in implref-global.S. 31standard_testfile .c .S 32 33# ${testfile} is now "implref-global". srcfile2 is "implref-global.S". 34set executable ${testfile} 35set asm_file [standard_output_file ${srcfile2}] 36 37# We need to know the size of integer and address types in order 38# to write some of the debugging info we'd like to generate. 39# 40# For that, we ask GDB by debugging our implref-global program. 41# Any program would do, but since we already have implref-global 42# specifically for this testcase, might as well use that. 43if [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] { 44 return -1 45} 46 47# Create the DWARF. We need a regular variable and a reference to it that'll 48# be marked with DW_OP_GNU_implicit_pointer. The variable must be global so 49# that its name is an exported symbol that we can reference from the DWARF 50# using gdb_target_symbol. 51Dwarf::assemble ${asm_file} { 52 cu {} { 53 DW_TAG_compile_unit { 54 {DW_AT_language @DW_LANG_C_plus_plus} 55 } { 56 declare_labels int_label variable_label ref_label 57 set int_size [get_sizeof "int" -1] 58 59 # gdb always assumes references are implemented as pointers. 60 set addr_size [get_sizeof "void *" -1] 61 62 int_label: DW_TAG_base_type { 63 {DW_AT_byte_size ${int_size} DW_FORM_udata} 64 {DW_AT_encoding @DW_ATE_signed} 65 {DW_AT_name "int"} 66 } 67 68 ref_label: DW_TAG_reference_type { 69 {DW_AT_byte_size ${addr_size} DW_FORM_udata} 70 {DW_AT_type :${int_label}} 71 } 72 73 variable_label: DW_TAG_variable { 74 {DW_AT_name "global_var"} 75 {DW_AT_type :${int_label}} 76 {DW_AT_external 1 DW_FORM_flag} 77 {DW_AT_location {DW_OP_addr [gdb_target_symbol "global_var"]} SPECIAL_expr} 78 } 79 80 DW_TAG_subprogram { 81 {MACRO_AT_func { "main" }} 82 {DW_AT_type :${int_label}} 83 {DW_AT_external 1 DW_FORM_flag} 84 } { 85 DW_TAG_variable { 86 {DW_AT_name "ref"} 87 {DW_AT_type :${ref_label}} 88 {DW_AT_location {DW_OP_GNU_implicit_pointer ${variable_label} 0} SPECIAL_expr} 89 } 90 } 91 } 92 } 93} 94 95if [prepare_for_testing "failed to prepare" ${executable} [list ${asm_file} ${srcfile}] {}] { 96 return -1 97} 98 99# DW_OP_GNU_implicit_pointer implementation requires a valid frame. 100if ![runto_main] { 101 return -1 102} 103 104# Address of the referenced value. 105set address [get_hexadecimal_valueof "&global_var" ""] 106 107# Doing 'print ref' should show us e.g. '(int &) @0xdeadbeef: 42'. 108gdb_test "print ref" " = \\(int &\\) @${address}: \\\d+" 109 110# Doing 'print &ref' should show us e.g. '(int *) 0xdeadbeef <global_var>'. 111gdb_test "print &ref" " = \\(int \\*\\) ${address} <global_var>" 112 113# gdb assumes C++ references are implemented as pointers, and print &(&ref) 114# shows us the underlying pointer's address. Since in this case there's no 115# physical pointer, gdb should tell us so. 116gdb_test "print &(&ref)" "Attempt to take address of value not located in memory." 117 118# Test assignment through the synthetic reference. 119set new_value 10 120gdb_test_no_output "set (ref = ${new_value})" 121gdb_test "print ref" " = \\(int &\\) @${address}: ${new_value}" "print ref after assignment" 122gdb_test "print global_var" " = ${new_value}" "print global_var after assignment" 123