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
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index e7549c8..aef3d4b 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -1415,6 +1415,17 @@
return nullptr;
}
+llvm::Optional<SymbolFile::ArrayInfo>
+SymbolFileDWARF::GetDynamicArrayInfoForUID(
+ lldb::user_id_t type_uid, const lldb_private::ExecutionContext *exe_ctx) {
+ std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
+ DWARFDIE type_die = GetDIEFromUID(type_uid);
+ if (type_die)
+ return DWARFASTParser::ParseChildArrayInfo(type_die, exe_ctx);
+ else
+ return llvm::None;
+}
+
Type *SymbolFileDWARF::ResolveTypeUID(const DIERef &die_ref) {
return ResolveType(GetDIE(die_ref), true);
}