| commit | 3a2026b39ae3b7d6cceef25b8c19a1708f19918c | [log] [tgz] |
|---|---|---|
| author | Lukasz Anforowicz <lukasza@google.com> | Thu Jun 09 09:08:42 2022 -0700 |
| committer | Copybara-Service <copybara-worker@google.com> | Thu Jun 09 09:09:13 2022 -0700 |
| tree | c778147a1f4b502ad55011d864cc16ede138e812 | |
| parent | 4180ffe0fd9c740f1993e2070e5c79742e41b6bb [diff] |
Fixing infinite recursion in ConvertTemplateSpecializationType.
Before this CL, a class template with a member function that
refers back to the same class ...
```cpp
template <typename T>
struct MyTemplate {
void MyMethod(const MyTemplate<T>& other) const {}
};
using MyTypeAlias = MyTemplate<int>;
```
... would cause an infinite recursion:
```txt
...
Importer::ConvertTemplateSpecializationType() <- importing MyTemplate<int>
Importer::ConvertType() at importer.cc:746:12
Importer::ConvertQualType() at importer.cc:767:7
Importer::ConvertType() at importer.cc:694:5
Importer::ConvertQualType() at importer.cc:767:7
FunctionDeclImporter::Import() at function.cc:69:29 <- importing MyMethod
DeclImporterBase<clang::FunctionDecl>::ImportDecl() ...
Importer::ImportDecl() at importer.cc:461:26
Importer::GetDeclItem() at importer.cc:452:38
Importer::GetItemIdsInSourceOrder() at importer.cc:331:9
CXXRecordDeclImporter::Import() at cxx_record.cc:137:25
DeclImporterBase<clang::CXXRecordDecl>::ImportDecl() ...
Importer::ImportDecl() at importer.cc:461:26
Importer::GetDeclItem() at importer.cc:452:38
Importer::ConvertTemplateSpecializationType() <- importing MyTemplate<int>
...
```
The problem above was introduced in https://github.com/google/crubit/commit/14732b2920053fadd06917ffd9201cd6d64704ff which started to call
ConvertTemplateSpecializationType from ConvertType (rather than from
TypedefNameDeclImporter::Import which won't be recursively reentered
in this scenario).
This CL prevents the infinite recursion by checking `known_types_` to
check if the `ClassTemplateSpecializationDecl` has been already
processed before.
Interestingly, I've wondered about the infinite recursion before, but
dismissed this problem, because I thought that it is sufficiently tested
via `this` parameter of instance methods (which already had some test
coverage). It turned out that this coverage is insufficient, because
`method_decl->getThisType()` doesn't use `TemplateSpecializationType`.
PiperOrigin-RevId: 453939417
Extremely experimental interop tooling for C++ and Rust.
Please don‘t use, this is an experiment and we don’t yet know where will it take us. There will be breaking changes without warning. Unfortunately, we can't take contributions at this point.
$ apt install clang lld bazel $ git clone git@github.com:google/crubit.git $ cd crubit $ bazel build --linkopt=-fuse-ld=/usr/bin/ld.lld //rs_bindings_from_cc:rs_bindings_from_cc_impl
$ git clone https://github.com/llvm/llvm-project $ cd llvm-project $ CC=clang CXX=clang++ cmake -S llvm -B build -DLLVM_ENABLE_PROJECTS='clang' -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=install $ cmake --build build -j $ # wait... $ cmake --install build $ cd ../crubit $ LLVM_INSTALL_PATH=../llvm-project/install bazel build //rs_bindings_from_cc:rs_bindings_from_cc_impl