例如下面是一个数组的debug信息
(gdb) debug_tree attr->expr
<var_decl 0x2a96140a00 b
type <array_type 0x2a96154f00
type <real_type 0x2a9608c6c0 float sizes-gimplified SF
size <integer_cst 0x2a96066900 constant 32>
unit size <integer_cst 0x2a96066570 constant 4>
align 32 symtab 0 alias set 2 canonical type 0x2a9608c6c0
precision 32
pointer_to_this <pointer_type 0x2a9608c900>>
sizes-gimplified BLK
size <integer_cst 0x2a9617e390 constant 327680>
unit size <integer_cst 0x2a9617e3c0 constant 40960>
align 32 symtab 0 alias set 2 canonical type 0x2a96154f00
domain <integer_type 0x2a96154e40 type <integer_type
0x2a9607d000 unsigned int>
sizes-gimplified SI size <integer_cst 0x2a96066900 32>
unit size <integer_cst 0x2a96066570 4>
align 32 symtab 0 alias set -1 canonical type 0x2a96154e40
precision 32 min <integer_cst 0x2a960665a0 0> max <integer_cst
0x2a9617e300 10239>>
pointer_to_this <pointer_type 0x2a961806c0>>
addressable used BLK file loop.c line 8 col 13 size <integer_cst
0x2a9617e390 327680> unit size <integer_cst 0x2a9617e3c0 40960>
align 128 context <function_decl 0x2a96155f00 test>
(mem/s/c:BLK (reg/f:SI 78 $frame) [2 b+0 S40960 A128]) chain
<var_decl 0x2a96140aa0 c>>