Fix (and improve) the support for C99 variable length array types
Clang recently improved its DWARF support for C VLA types. The DWARF
now looks like this:
0x00000051: DW_TAG_variable [4]
DW_AT_location( fbreg -32 ) DW_AT_name( "__vla_expr" ) DW_AT_type( {0x000000d3} ( long unsigned int ) ) DW_AT_artificial( true )
...
0x000000da: DW_TAG_array_type [10] *
DW_AT_type( {0x000000cc} ( int ) )
0x000000df: DW_TAG_subrange_type [11]
DW_AT_type( {0x000000e9} ( __ARRAY_SIZE_TYPE__ ) ) DW_AT_count( {0x00000051} )
Without this patch LLDB will naively interpret the DIE offset 0x51 as
the static size of the array, which is clearly wrong. This patch
extends ValueObject::GetNumChildren to query the dynamic properties of
incomplete array types.
See the testcase for an example:
4 int foo(int a) { 5 int vla[a]; 6 for (int i = 0; i < a; ++i) 7 vla[i] = i; 8
-> 9 pause(); // break here
10 return vla[a-1]; 11 }
(lldb) fr v vla
(int []) vla = ([0] = 0, [1] = 1, [2] = 2, [3] = 3)
(lldb) quit
rdar://problem/21814005
Differential Revision: https://reviews.llvm.org/D53530
llvm-svn: 346165