| Issue |
182762
|
| Summary |
[lldb] Failure to resolve templated dynamic type
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
mentlerd
|
LLDB sometimes fails to correctly resolve the dynamic type of pointers. Consider this example on macOS:
```c++
struct Interface {
virtual ~Interface() {}
};
struct Simple : public Interface {};
template<typename T>
struct Complex : public Interface {};
template<typename T>
struct Wrapper {};
int main(int argc, const char* argv[]) {
Interface* A = new Simple(); // (Simple *) 0x00000001007d47f0
Interface* B = new Complex<int>(); // (Complex<int> *) 0x00000001007d6460
Interface* C = new Complex<Wrapper<int>>(); // (Interface *) 0x00000001007d6c30 <-- Bug!
__builtin_debugtrap();
return 0;
}
```
I have chased this down to [`ItaniumABILanguageRuntime::GetTypeInfo`](https://github.com/llvm/llvm-project/blob/main/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp#L57) failing in the case of `C` because it is looking for a different class name than what is contained in the DWARF.
```
(lldb) p lookup_name
(std::string) "::Complex<Wrapper<int>>"
0x00000106: DW_TAG_structure_type
DW_AT_containing_type (0x00000061 "Interface")
DW_AT_calling_convention (DW_CC_pass_by_reference)
DW_AT_name ("Complex<Wrapper<int> >") // <-- Note the additional space between the closing chevrons!
DW_AT_byte_size (0x08)
DW_AT_decl_file ("/Users/mentlerd/personal/projects/sample/sample/main.cpp")
DW_AT_decl_line (9)
```
I have also confirmed that patching `lookup_name` here to the version with the space between the chevrons results in the correct dynamic type resolution.
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