SemaSourceWithPriorities is a special SemaSource that wraps our normal LLDB
ExternalASTSource and the ASTReader (which is used for the C++ module loading).
It's only active when the `import-std-module` setting is turned on.
The `CompleteType` function there in `SemaSourceWithPriorities` is looping over
all ExternalASTSources and asks each to complete the type. However, that loop is
in another loop that keeps doing that until the type is complete. If that
function is ever called on a type that is a forward decl then that causes LLDB
to go into an infinite loop.
I remember I added that second loop and the comment because I thought I saw a
similar pattern in some other Clang code, but after some grepping I can't find
that code anywhere and it seems the rest of the code base only calls
CompleteType once (It would also be kinda silly to have calling it multiple
times). So it seems that's just a silly mistake.
The is implicitly tested by importing `std::pair`, but I also added a simpler
dedicated test that creates a dummy libc++ module with some forward declarations
and then imports them into the scratch AST context. At some point the
ASTImporter will check if one of the forward decls could be completed by the
ExternalASTSource, which will cause the `SemaSourceWithPriorities` to go into an
infinite loop once it receives the `CompleteType` call.
Reviewed By: shafik
Differential Revision: https://reviews.llvm.org/D87289
Module.h takes 86ms to parse, mostly parsing the class itself. Avoid it
if possible. ASTContext.h depends on ExternalASTSource.h.
A few NFC changes were needed to make this possible:
- Move ASTSourceDescriptor to Module.h. This needs Module to be
complete, and seems more related to modules and AST files than
external AST sources.
- Move "import complete" bit from Module* pointer int pair to
NextLocalImport pointer. Required because PointerIntPair<Module*,...>
requires Module to be complete, and now it may not be.
Reviewed By: aaron.ballman, hans
Differential Revision: https://reviews.llvm.org/D75784
LLDB has a few different styles of header guards and they're not very
consistent because things get moved around or copy/pasted. This patch
unifies the header guards across LLDB and converts everything to match
LLVM's style.
Differential revision: https://reviews.llvm.org/D74743
Summary:
This patch is the MVP version of importing the std module into the expression parser to improve C++ debugging.
What happens in this patch is that we inject a `@import std` into our expression source code. We also
modify our internal Clang instance for parsing this expression to work with modules and debug info
at the same time (which is the main change in terms of LOC). We implicitly build the `std` module on the first use. The
C++ include paths for building are extracted from the debug info, which means that this currently only
works if the program is compiled with `-glldb -fmodules` and uses the std module. The C include paths
are currently specified by LLDB.
I enabled the tests currently only for libc++ and Linux because I could test this locally. I'll enable the tests
for other platforms once this has landed and doesn't break any bots (and I implemented the platform-specific
C include paths for them).
With this patch we can now:
* Build a libc++ as a module and import it into the expression parser.
* Read from the module while also referencing declarations from the debug info. E.g. `std::abs(local_variable)`.
What doesn't work (yet):
* Merging debug info and C++ module declarations. E.g. `std::vector<CustomClass>` doesn't work.
* Pretty much anything that involves the ASTImporter and templated code. As the ASTImporter is used for saving the result declaration, this means that we can't
call yet any function that returns a non-trivial type.
* Use libstdc++ for this, as it requires multiple include paths and Clang only emits one include path per module. Also libstdc++ doesn't support Clang modules without patches.
Reviewers: aprantl, jingham, shafik, friss, davide, serge-sans-paille
Reviewed By: aprantl
Subscribers: labath, mgorny, abidh, jdoerfert, lldb-commits
Tags: #c_modules_in_lldb, #lldb
Differential Revision: https://reviews.llvm.org/D58125
llvm-svn: 355939
Raphael Isemann