Re: [PATCH 1/9] Add test for modifiable DWARF locations

Yao Qi
2017-04-13T08:36:37Z

Andreas Arnez <arnez@linux.vnet.ibm.com> writes:

> This adds a test for read/write access to variables with various types of
> DWARF locations. It uses register- and memory locations and composite
> locations with register- and memory pieces.

The last line should be put into the introduction comment of
gdb.dwarf2/var-access.exp.

> +
> +# Choose suitable integer registers for the test.
> +
> +set dwarf_regnum {0 1}
> +
> +if { [istarget "aarch64*-*-*"] } {

if { [is_aarch64_target] }

> + set regname {x0 x1}
> +} elseif { [istarget "arm*-*-*"]

else if { [is_aarch32_target]

> + || [istarget "s390*-*-*" ]
> + || [istarget "powerpc*-*-*"]
> + || [istarget "rs6000*-*-aix*"] } {
> + set regname {r0 r1}
> +} elseif { [istarget "i?86-*-*"] } {
> + set regname {eax edx}
> +} elseif { [istarget "x86_64-*-*"] } {
> + set regname {rax rdx}
> +} else {
> + verbose "Skipping tests for accessing DWARF-described variables."
> + return
> +}
> +
> +standard_testfile .c ${gdb_test_file_name}-dw.S
> +
> +# Make some DWARF for the test.
> +
> +set asm_file [standard_output_file $srcfile2]
> +Dwarf::assemble $asm_file {
> + global srcdir subdir srcfile
> + global dwarf_regnum regname
> +
> + set main_func \
> + [function_range main [list ${srcdir}/${subdir}/$srcfile]]

> +
> + DW_TAG_subprogram {
> + {name "main"}
> + {DW_AT_external 1 flag}
> + {low_pc [lindex $main_func 0] DW_FORM_addr}
> + {high_pc [lindex $main_func 1] DW_FORM_udata}

You can use MACRO_AT_func, it can replace name, low_pc and high_pc.
Also, you don't need to call function_range above.

> + } {
> + # Simple memory location.
> + DW_TAG_variable {
> + {name "a"}
> + {type :$array_a8_label}
> + {location {
> + addr $buf_var
> + } SPECIAL_expr}
> + }
> + # Memory pieces.

Nit: we can also describe where are these pieces in comments, like

# Memory pieces, two bytes from &buf[0], and two
# bytes from &buf[2].

> + DW_TAG_variable {
> + {name "s1"}
> + {type :$struct_s_label}
> + {location {
> + addr $buf_var
> + plus_uconst 2
> + piece 2
> + addr $buf_var
> + piece 2
> + } SPECIAL_expr}
> + }
> + # Register- and memory pieces.

Likewise.

OK with the changes.

--
Yao (齐尧)