Currently LLDB's `ParseRustVariantPart` generates the following
`CXXRecordDecl` for a Rust enum
```rust
enum AA {
A(u8)
}
```
```
CXXRecordDecl 0x5555568d5970 <<invalid sloc>> <invalid sloc> struct AA
|-CXXRecordDecl 0x5555568d5ab0 <<invalid sloc>> <invalid sloc> union test_issue::AA$Inner definition
| |-CXXRecordDecl 0x5555568d5d18 <<invalid sloc>> <invalid sloc> struct A$Variant definition
| | |-DefinitionData pass_in_registers aggregate standard_layout trivially_copyable trivial
| | | `-Destructor simple irrelevant trivial needs_implicit
| | `-FieldDecl 0x555555a77880 <<invalid sloc>> <invalid sloc> value 'test_issue::AA::A'
| `-FieldDecl 0x555555a778f0 <<invalid sloc>> <invalid sloc> $variant$ 'test_issue::AA::test_issue::AA$Inner::A$Variant'
|-CXXRecordDecl 0x5555568d5c48 <<invalid sloc>> <invalid sloc> struct A definition
| `-FieldDecl 0x555555a777e0 <<invalid sloc>> <invalid sloc> __0 'unsigned char'
`-FieldDecl 0x555555a77960 <<invalid sloc>> <invalid sloc> $variants$ 'test_issue::AA::test_issue::AA$Inner'
```
While when the Rust enum type name is the same as its variant name, the
generated `CXXRecordDecl` becomes the following – there's a circular
reference between `struct A$Variant` and `struct A`, causing #163048.
```rust
enum A {
A(u8)
}
```
```
CXXRecordDecl 0x5555568d5760 <<invalid sloc>> <invalid sloc> struct A
|-CXXRecordDecl 0x5555568d58a0 <<invalid sloc>> <invalid sloc> union test_issue::A$Inner definition
| |-CXXRecordDecl 0x5555568d5a38 <<invalid sloc>> <invalid sloc> struct A$Variant definition
| | `-FieldDecl 0x5555568d5b70 <<invalid sloc>> <invalid sloc> value 'test_issue::A' <---- bug here
| `-FieldDecl 0x5555568d5be0 <<invalid sloc>> <invalid sloc> $variant$ 'test_issue::A::test_issue::A$Inner::A$Variant'
`-FieldDecl 0x5555568d5c50 <<invalid sloc>> <invalid sloc> $variants$ 'test_issue::A::test_issue::A$Inner'
```
The problem was caused by `GetUniqueTypeNameAndDeclaration` not
returning the correct qualified name for DWARF DIE `test_issue::A::A`,
instead, it returned `A`. This caused `ParseStructureLikeDIE` to find
the wrong type `test_issue::A` and returned early.
The failure in `GetUniqueTypeNameAndDeclaration` appears to stem from a
language check that returns early unless the language is C++. I changed
it so Rust follows the C++ path rather than returning. I’m not entirely
sure this is the right approach — Rust’s qualified name rules look
similar, but not identical? Alternatively, we could add a Rust-specific
implementation that forms qualified names according to Rust's rules.
In one of my recent PRs I mistakenly had two test-cases with the same
name, preventing one of them to run. Since it's an easy mistake to make
(e.g., copy pasting existing test-cases), I ran following sanity-check
script over `lldb/test/API`, which found couple of tests which were
losing coverage because of this (or in some cases simply had duplicate
tests):
```
import ast
import sys
filename = sys.argv[1]
print(f'Checking {filename}...')
tree = ast.parse(open(filename, 'r').read())
for node in ast.walk(tree):
if not isinstance(node, ast.ClassDef):
continue
func_names = []
for child in ast.iter_child_nodes(node):
if isinstance(child, ast.FunctionDef):
func_names.append(child.name)
seen_func_names = set()
duplicate_func_names = []
for name in func_names:
if name in seen_func_names:
duplicate_func_names.append(name)
else:
seen_func_names.add(name)
if len(duplicate_func_names) != 0:
print(f'Multiple func names found:\n\t{duplicate_func_names}\n\tclass {node.name}\n\tfile: {filename}')
```
This patch fixes these cases.
LLDB doesn't yet have a TypeSystemRust implemented however it is used to debug Rust applications. Most of the types map well enough to Clang types and there are python formatters implemented to display those types reasonably well in a debugger.
However, Rust enums are completely ignored by LLDB as Clang never emits DW_TAG_variant_part inside DW_TAG_structure_type
This diff adds a parser for DW_TAG_variant_part (Rust-only) that creates a matching valid Clang declaration to the Rust enum. As long as there is enough information and all fields have correct offsets synthetic/summary providers can be implemented to display it correctly when debugging Rust code
Differential Revision: https://reviews.llvm.org/D149213
