[gdb/testsuite] Add testcase for DW_AT_count referencing a variable

Clang describes the upper bounds of variable length arrays using
a DW_AT_count attribute which references the DIE of a synthetic
variable whose value is specified using a DW_AT_location.  GDB handles
these incorrectly if the corresponding DWARF expression finishes with a
DW_OP_stack_value (PR26905).  This commit adds a new kfailed test to
gdb.dwarf2/count.exp with the same DWARF as that generated by Clang for
gdb.base/vla-optimized-out.exp, one of the failing tests.

Checked on Fedora 32 x86_64, with GCC and Clang.

gdb/testsuite/ChangeLog:

2020-11-22  Gary Benson <gbenson@redhat.com>

	PR gdb/26905
	* gdb.dwarf2/count.exp: Add test for an array whose upper bound
	is defined using a DW_AT_count which references another DIE.

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index b89633fb9ec076f7dd2878aa73a8efac84487407..91fc9e0112faf7106a4cac19e6fb3679f67e0f6b 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-11-22  Gary Benson <gbenson@redhat.com>
+
+       PR gdb/26905
+       * gdb.dwarf2/count.exp: Add test for an array whose upper bound
+       is defined using a DW_AT_count which references another DIE.
+
 2020-11-21  Tom de Vries  <tdevries@suse.de>
 
        * gdb.base/vla-ptr.exp: Add XFAIL.

diff --git a/gdb/testsuite/gdb.dwarf2/count.exp b/gdb/testsuite/gdb.dwarf2/count.exp
index 5cefb15da4af84f0f95cffac3bbad737e909f2b2..6dcccb574098a283091e700c0bad9642231db73a 100644 (file)
--- a/gdb/testsuite/gdb.dwarf2/count.exp
+++ b/gdb/testsuite/gdb.dwarf2/count.exp
@@ -28,7 +28,10 @@ set asm_file [standard_output_file $srcfile2]
 Dwarf::assemble $asm_file {
     cu {} {
        compile_unit {{language @DW_LANG_C99}} {
-           declare_labels char_label array_label array_label2 static_array_label
+           declare_labels char_label \
+               array_size_type_label long_unsigned_int_label \
+               array_label array_label2 static_array_label \
+               vla_length_label vla_array_label
 
            char_label: base_type {
                {name char}
@@ -36,6 +39,18 @@ Dwarf::assemble $asm_file {
                {byte_size 1 DW_FORM_sdata}
            }
 
+           array_size_type_label: base_type {
+               {byte_size 8 DW_FORM_sdata}
+               {encoding @DW_ATE_unsigned}
+               {name __ARRAY_SIZE_TYPE__}
+           }
+
+           long_unsigned_int_label: base_type {
+               {byte_size 8 DW_FORM_sdata}
+               {encoding @DW_ATE_unsigned}
+               {name "long unsigned int"}
+           }
+
            array_label: array_type {
                {type :$char_label}
            } {
@@ -63,6 +78,27 @@ Dwarf::assemble $asm_file {
                }
            }
 
+           vla_length_label:
+           DW_TAG_variable {
+               {location
+                   {
+                       lit6
+                       stack_value
+                   } SPECIAL_expr}
+               {name "__vla_array_length"}
+               {type :$long_unsigned_int_label}
+               {artificial 1 DW_FORM_flag_present}
+           }
+
+           vla_array_label: array_type {
+               {type :$char_label}
+           } {
+               subrange_type {
+                   {type :$array_size_type_label}
+                   {count :$vla_length_label}
+               }
+           }
+
            DW_TAG_variable {
                {name array2}
                {type :$array_label2}
@@ -80,6 +116,12 @@ Dwarf::assemble $asm_file {
                {type :$static_array_label}
                {const_value world DW_FORM_block1}
            }
+
+           DW_TAG_variable {
+               {name vla_array}
+               {type :$vla_array_label}
+               {const_value saluton DW_FORM_block1}
+           }
        }
     }
 }
@@ -123,3 +165,12 @@ gdb_test "ptype static_array" "type = char \\\[5\\\]"
 gdb_test "whatis static_array" "type = char \\\[5\\\]"
 gdb_test "print static_array" " = \"world\""
 gdb_test "print sizeof static_array" " = 5"
+
+setup_kfail "gdb/26905" *-*-*
+gdb_test "ptype vla_array" "type = char \\\[6\\\]"
+setup_kfail "gdb/26905" *-*-*
+gdb_test "whatis vla_array" "type = char \\\[6\\\]"
+setup_kfail "gdb/26905" *-*-*
+gdb_test "print vla_array" " = \"saluto\""
+setup_kfail "gdb/26905" *-*-*
+gdb_test "print sizeof vla_array" " = 6"