1# Copyright 2016-2019 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 array 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-array.S. 31standard_testfile .c .S 32 33# ${testfile} is now "implref-array". srcfile2 is "implref-array.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-array program. 41# Any program would do, but since we already have implref-array 42# specifically for this testcase, might as well use that. 43if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] } { 44 return -1 45} 46 47set array_length [get_valueof "/u" "sizeof(array) / sizeof(array\[0\])" -1] 48 49# Create the DWARF. We need a regular variable which represents the array, and 50# a reference to it that'll be marked with DW_OP_GNU_implicit_pointer. 51# The variable must be global so that its name is an exported symbol that we 52# can reference from the DWARF using gdb_target_symbol. 53Dwarf::assemble ${asm_file} { 54 global srcdir subdir srcfile array_length 55 56 cu {} { 57 DW_TAG_compile_unit { 58 {DW_AT_language @DW_LANG_C_plus_plus} 59 } { 60 declare_labels int_label sizetype_label array_label variable_label ref_label 61 set int_size [get_sizeof "int" -1] 62 set upper_bound [expr ${array_length} - 1] 63 64 # gdb always assumes references are implemented as pointers. 65 set addr_size [get_sizeof "void *" -1] 66 67 int_label: DW_TAG_base_type { 68 {DW_AT_byte_size ${int_size} DW_FORM_udata} 69 {DW_AT_encoding @DW_ATE_signed} 70 {DW_AT_name "int"} 71 } 72 73 sizetype_label: DW_TAG_base_type { 74 {DW_AT_byte_size ${int_size} DW_FORM_udata} 75 {DW_AT_encoding @DW_ATE_unsigned} 76 {DW_AT_name "sizetype"} 77 } 78 79 array_label: DW_TAG_array_type { 80 {DW_AT_type :${int_label}} 81 } { 82 DW_TAG_subrange_type { 83 {DW_AT_type :${sizetype_label}} 84 {DW_AT_lower_bound 0 DW_FORM_udata} 85 {DW_AT_upper_bound ${upper_bound} DW_FORM_udata} 86 } 87 } 88 89 ref_label: DW_TAG_reference_type { 90 {DW_AT_byte_size ${addr_size} DW_FORM_udata} 91 {DW_AT_type :${array_label}} 92 } 93 94 variable_label: DW_TAG_variable { 95 {DW_AT_name "array"} 96 {DW_AT_type :${array_label}} 97 {DW_AT_external 1 DW_FORM_flag} 98 {DW_AT_location {DW_OP_addr [gdb_target_symbol "array"]} SPECIAL_expr} 99 } 100 101 DW_TAG_subprogram { 102 {MACRO_AT_func { "main" "${srcdir}/${subdir}/${srcfile}" }} 103 {DW_AT_type :${int_label}} 104 {DW_AT_external 1 DW_FORM_flag} 105 } { 106 DW_TAG_variable { 107 {DW_AT_name "ref"} 108 {DW_AT_type :${ref_label}} 109 {DW_AT_location {DW_OP_GNU_implicit_pointer ${variable_label} 0} SPECIAL_expr} 110 } 111 } 112 } 113 } 114} 115 116if [prepare_for_testing "failed to prepare" ${executable} [list ${asm_file} ${srcfile}] {}] { 117 return -1 118} 119 120# DW_OP_GNU_implicit_pointer implementation requires a valid frame. 121if ![runto_main] { 122 return -1 123} 124 125# This matches e.g. '(int (&)[5])' 126set ref_type [format {\(int \(&\)\[%d\]\)} ${array_length}] 127 128# This matches e.g. '(int (*)[5])' 129set ptr_type [format {\(int \(\*\)\[%d\]\)} ${array_length}] 130 131# Contents of the array. Trim leading/trailing whitespace, '{' and '}' 132# since they confuse TCL to no end. 133set contents [get_valueof "" "array" ""] 134set contents [string trim ${contents}] 135set contents [string trim ${contents} "{}"] 136 137# Address of the referenced value. 138set address [get_hexadecimal_valueof "&array" ""] 139 140# Doing 'print ref' should show us e.g. '(int (&)[5]) 0xdeadbeef: {0, 1, 2, 3, 4}'. 141gdb_test "print ref" " = ${ref_type} @${address}: \\{${contents}\\}" 142 143# Doing 'print &ref' should show us e.g. '(int (*)[5]) 0xdeadbeef <array>'. 144gdb_test "print &ref" " = ${ptr_type} ${address} <array>" 145 146# gdb assumes C++ references are implemented as pointers, and print &(&ref) 147# shows us the underlying pointer's address. Since in this case there's no 148# physical pointer, gdb should tell us so. 149gdb_test "print &(&ref)" "Attempt to take address of value not located in memory." 150 151# Test assignment through the synthetic reference. 152set first_value 10 153gdb_test_no_output "set (ref\[0\] = ${first_value})" 154 155# This matches '{10, 1, 2, 3, 4}'. 156set new_contents [format {\{%d, 1, 2, 3, 4\}} ${first_value}] 157 158# Doing 'print ref' should now show us e.g. 159# '(int (&)[5]) <synthetic pointer>: {10, 1, 2, 3, 4}'. 160gdb_test "print ref" " = ${ref_type} @${address}: ${new_contents}" "print ref after assignment" 161gdb_test "print array" " = ${new_contents}" "print array after assignment" 162 163# Test treating the array as a pointer. 164set second_value 20 165set new_contents [format {\{%d, %d, 2, 3, 4\}} ${first_value} ${second_value}] 166 167gdb_test "print *ref" " = ${first_value}" 168gdb_test_no_output "set (*(ref + 1) = ${second_value})" 169gdb_test "print ref\[1\]" " = ${second_value}" 170gdb_test "print array" " = ${new_contents}" "print array after second assignment" 171