bfca584fae
This change is relevant only for standard DWARF (as opposed to the GNAT encodings extensions): at the time of writing it only makes a difference with GCC patches that are to be integrated: see the patch series submission at <https://gcc.gnu.org/ml/gcc-patches/2015-07/msg01353.html>. Given the following Ada declarations: subtype Small_Int is Natural range 0 .. 100; type R_Type (L : Small_Int := 0) is record S : String (1 .. L); end record; type A_Type is array (Natural range <>) of R_Type; A : A_Type := (1 => (L => 0, S => ""), 2 => (L => 2, S => "ab")); Before this change, we would get the following GDB session: (gdb) ptype a type = array (1 .. 2) of foo.r_type <packed: 838-bit elements> This is wrong: "a" is not a packed array. This output comes from the fact that, because R_Type has a dynamic size (with a maximum), the compiler has to describe in the debugging information the size allocated for each array element (i.e. the stride, in DWARF parlance: see DW_AT_byte_stride). Ada type printing currently assumes that arrays with a stride are packed, hence the above output. In practice, GNAT never performs bit-packing for arrays that contain variable-sized elements. Leveraging this fact, this patch enhances type printing so that ptype does not pretend that arrays are packed when they have a stride and they contain dynamic elements. After this change, we get the following expected output: (gdb) ptype a type = array (1 .. 2) of foo.r_type gdb/ChangeLog: * ada-typeprint.c (print_array_type): Do not describe arrays as packed when they embed dynamic elements. gdb/testsuite/ChangeLog: * gdb.ada/array_of_variable_length.exp: New testcase. * gdb.ada/array_of_variable_length/foo.adb: New file. * gdb.ada/array_of_variable_length/pck.adb: New file. * gdb.ada/array_of_variable_length/pck.ads: New file. Tested on x86_64-linux, no regression.
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