1 files changed, 186 insertions, 0 deletions
diff --git a/gdb/testsuite/gdb.dwarf2/implref-struct.exp b/gdb/testsuite/gdb.dwarf2/implref-struct.exp
new file mode 100644
index 0000000..49967e3
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/implref-struct.exp
@@ -0,0 +1,186 @@
+# Copyright 2016 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 global struct whose location is a DW_OP_addr.
+
+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-struct.S.
+standard_testfile .c .S
+
+# ${testfile} is now "implref-struct".  srcfile2 is "implref-struct.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-struct program.
+# Any program would do, but since we already have implref-struct
+# specifically for this testcase, might as well use that.
+if [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile} {debug c++}] {
+    untested ${testfile}.exp
+    return -1
+}
+
+# Create the DWARF.  We need a regular variable for the struct and a reference
+# to it that'll be marked with DW_OP_GNU_implicit_pointer. The variable must be
+# global so that its name is an exported symbol that can we can reference from
+# the DWARF using gdb_target_symbol.
+Dwarf::assemble ${asm_file} {
+    global srcdir subdir srcfile
+
+    cu {} {
+	DW_TAG_compile_unit {
+	    {DW_AT_language @DW_LANG_C_plus_plus}
+	} {
+	    declare_labels int_label struct_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 S_size [get_sizeof "S" -1]
+
+	    # The compiler shouldn't introduce structure padding here.
+	    set b_offset 4
+	    set c_offset 8
+
+	    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"}
+	    }
+
+	    struct_label: DW_TAG_structure_type {
+		{DW_AT_name "S"}
+		{DW_AT_byte_size ${S_size} DW_FORM_udata}
+	    } {
+		DW_TAG_member {
+		    {DW_AT_name "a"}
+		    {DW_AT_type :${int_label}}
+		    {DW_AT_data_member_location 0 DW_FORM_udata}
+		}
+
+		DW_TAG_member {
+		    {DW_AT_name "b"}
+		    {DW_AT_type :${int_label}}
+		    {DW_AT_data_member_location ${b_offset} DW_FORM_udata}
+		}
+
+		DW_TAG_member {
+		    {DW_AT_name "c"}
+		    {DW_AT_type :${int_label}}
+		    {DW_AT_data_member_location ${c_offset} DW_FORM_udata}
+		}
+	    }
+
+	    ref_label: DW_TAG_reference_type {
+		{DW_AT_byte_size ${addr_size} DW_FORM_udata}
+		{DW_AT_type :${struct_label}}
+	    }
+
+	    variable_label: DW_TAG_variable {
+		{DW_AT_name "s1"}
+		{DW_AT_type :${struct_label}}
+		{DW_AT_external 1 DW_FORM_flag}
+		{DW_AT_location {DW_OP_addr [gdb_target_symbol "s1"]} SPECIAL_expr}
+	    }
+
+	    DW_TAG_variable {
+		{DW_AT_name "s2"}
+		{DW_AT_type :${struct_label}}
+		{DW_AT_external 1 DW_FORM_flag}
+		{DW_AT_location {DW_OP_addr [gdb_target_symbol "s2"]} SPECIAL_expr}
+	    }
+
+	    DW_TAG_subprogram {
+		{MACRO_AT_func { "main" "${srcdir}/${subdir}/${srcfile}" }}
+		{DW_AT_type :${int_label}}
+		{DW_AT_external 1 DW_FORM_flag}
+	    } {
+	        DW_TAG_variable {
+		    {DW_AT_name "ref"}
+		    {DW_AT_type :${ref_label}}
+		    {DW_AT_location {DW_OP_GNU_implicit_pointer ${variable_label} 0} SPECIAL_expr}
+		}
+	    }
+	}
+    }
+}
+
+if [prepare_for_testing ${testfile}.exp ${executable} [list ${asm_file} ${srcfile}] {}] {
+    return -1
+}
+
+# DW_OP_GNU_implicit_pointer implementation requires a valid frame.
+if ![runto_main] {
+    return -1
+}
+
+# Returns the struct members, e.g. '{a = 0, b = 1, c = 2}'.
+proc get_members {var} {
+    set members [get_valueof "" ${var} ""]
+
+    # Trim leading/trailing whitespace, '{' and '}' since they confuse TCL to no end.
+    set members [string trim ${members}]
+    set members [string trim ${members} "{}"]
+
+    return ${members}
+}
+
+# Values of the struct members.
+set s1_members [get_members "s1"]
+set s2_members [get_members "s2"]
+
+# Address of the referenced value.
+set address [get_hexadecimal_valueof "&s1" ""]
+
+# Test printing with both 'set print object off' and 'on', just to make sure
+# the output doesn't change.
+foreach_with_prefix print-object {"off" "on"} {
+    gdb_test_no_output "set print object ${print-object}"
+
+    # Doing 'print ref' should show us e.g.
+    # '(S &) @0xdeadbeef: {a = 0, b = 1, c = 2}'.
+    gdb_test "print ref" " = \\(S &\\) @${address}: \\{${s1_members}\\}"
+
+    # Doing 'print &ref' should show us e.g. '(S *) 0xdeadbeef <s1>'.
+    gdb_test "print &ref" " = \\(S \\*\\) ${address} <s1>"
+
+    # 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."
+}
+
+# Test assignment through the synthetic reference.
+gdb_test_no_output "set (ref = s2)"
+
+foreach_with_prefix print-object {"off" "on"} {
+    gdb_test_no_output "set print object ${print-object}"
+
+    gdb_test "print ref" " = \\(S &\\) @${address}: \\{${s2_members}\\}" "print ref after assignment"
+    gdb_test "print s1" " = \\{${s2_members}\\}" "print s1 after assignment"
+}