Hi,
I observed that gfortran 7.2 and 8.0 generate different debug info for
dynamical array. Here is a case simplified from gdb test case
gdb.fortran/vla-datatypes.f90
$ cat vla-datatypes.f90
program vla_primitives
integer, allocatable :: intvla(:, :, :)
logical :: l
allocate (intvla (11,22,33))
l = allocated(intvla) ! vlas-allocated
intvla(:,:,:) = 1
intvla(5,5,5) = 42 ! vlas-initialized
end program vla_primitives
In gcc 8.0, the intvla debug info is,
<2><b2>: Abbrev Number: 10 (DW_TAG_variable)
<b3> DW_AT_name : (indirect string, offset: 0xcb): intvla
<b7> DW_AT_decl_file : 1
<b8> DW_AT_decl_line : 2
<b9> DW_AT_type : <0x127>
<bd> DW_AT_location : 3 byte block: 91 e0 7e (DW_OP_fbreg: -160)
<1><127>: Abbrev Number: 14 (DW_TAG_array_type)
<128> DW_AT_ordering : 1 (column major)
<129> DW_AT_data_location: 4 byte block: 97 23 8 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 8; DW_OP_deref)
<12e> DW_AT_allocated : 6 byte block: 97 23 8 6 30 2e
(DW_OP_push_object_address; DW_OP_plus_uconst: 8; DW_OP_deref; DW_OP_lit0;
DW_OP_ne)
<135> DW_AT_type : <0x7b>
<139> DW_AT_sibling : <0x174>
<2><13d>: Abbrev Number: 15 (DW_TAG_subrange_type)
<13e> DW_AT_lower_bound : 4 byte block: 97 23 28 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 40; DW_OP_deref)
<143> DW_AT_upper_bound : 4 byte block: 97 23 30 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 48; DW_OP_deref)
<148> DW_AT_byte_stride : 6 byte block: 97 23 20 6 34 1e
(DW_OP_push_object_address; DW_OP_plus_uconst: 32; DW_OP_deref; DW_OP_lit4;
DW_OP_mul)
<2><14f>: Abbrev Number: 15 (DW_TAG_subrange_type)
<150> DW_AT_lower_bound : 4 byte block: 97 23 40 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 64; DW_OP_deref)
<155> DW_AT_upper_bound : 4 byte block: 97 23 48 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 72; DW_OP_deref)
<15a> DW_AT_byte_stride : 6 byte block: 97 23 38 6 34 1e
(DW_OP_push_object_address; DW_OP_plus_uconst: 56; DW_OP_deref; DW_OP_lit4;
DW_OP_mul)
<2><161>: Abbrev Number: 15 (DW_TAG_subrange_type)
<162> DW_AT_lower_bound : 4 byte block: 97 23 58 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 88; DW_OP_deref)
<167> DW_AT_upper_bound : 4 byte block: 97 23 60 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 96; DW_OP_deref)
<16c> DW_AT_byte_stride : 6 byte block: 97 23 50 6 34 1e
(DW_OP_push_object_address; DW_OP_plus_uconst: 80; DW_OP_deref; DW_OP_lit4;
DW_OP_mul)
<2><173>: Abbrev Number: 0
In gcc 7.2, it is,
<2><b2>: Abbrev Number: 10 (DW_TAG_variable)
<b3> DW_AT_name : (indirect string, offset: 0x12): intvla
<b7> DW_AT_decl_file : 1
<b8> DW_AT_decl_line : 2
<b9> DW_AT_type : <0x127>
<bd> DW_AT_location : 3 byte block: 91 e0 7e (DW_OP_fbreg: -160)
<1><127>: Abbrev Number: 14 (DW_TAG_array_type)
<128> DW_AT_ordering : 1 (column major)
<129> DW_AT_data_location: 2 byte block: 97 6
(DW_OP_push_object_address; DW_OP_deref)
<12c> DW_AT_allocated : 4 byte block: 97 6 30 2e
(DW_OP_push_object_address; DW_OP_deref; DW_OP_lit0; DW_OP_ne)
<131> DW_AT_type : <0x7b>
<135> DW_AT_sibling : <0x170>
<2><139>: Abbrev Number: 15 (DW_TAG_subrange_type)
<13a> DW_AT_lower_bound : 4 byte block: 97 23 20 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 32; DW_OP_deref)
<13f> DW_AT_upper_bound : 4 byte block: 97 23 28 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 40; DW_OP_deref)
<144> DW_AT_byte_stride : 6 byte block: 97 23 18 6 34 1e
(DW_OP_push_object_address; DW_OP_plus_uconst: 24; DW_OP_deref; DW_OP_lit4;
DW_OP_mul)
<2><14b>: Abbrev Number: 15 (DW_TAG_subrange_type)
<14c> DW_AT_lower_bound : 4 byte block: 97 23 38 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 56; DW_OP_deref)
<151> DW_AT_upper_bound : 4 byte block: 97 23 40 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 64; DW_OP_deref)
<156> DW_AT_byte_stride : 6 byte block: 97 23 30 6 34 1e
(DW_OP_push_object_address; DW_OP_plus_uconst: 48; DW_OP_deref; DW_OP_lit4;
DW_OP_mul)
<2><15d>: Abbrev Number: 15 (DW_TAG_subrange_type)
<15e> DW_AT_lower_bound : 4 byte block: 97 23 50 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 80; DW_OP_deref)
<163> DW_AT_upper_bound : 4 byte block: 97 23 58 6
(DW_OP_push_object_address; DW_OP_plus_uconst: 88; DW_OP_deref)
<168> DW_AT_byte_stride : 6 byte block: 97 23 48 6 34 1e
(DW_OP_push_object_address; DW_OP_plus_uconst: 72; DW_OP_deref; DW_OP_lit4;
DW_OP_mul)
<2><16f>: Abbrev Number:
Attributes DW_AT_data_location and DW_AT_allocated are different. There
is an extra "DW_OP_plus_uconst: 8" generated by gcc 8.0. Is it
intended or expected? gfortran 8.0 causes many gdb.fotran vla-related
tests fail, but gfortran 7.2 doesn't. That is why I took a look at the
debug information.
--
Yao (齐尧)
