* Include `DeclContext` of the node where possible
* Add 'default-with-decl-contexts' dump style that dumps the dect context
hierarchy in addition to the AST
* Support `-dump-parse` with `-dump-ast-format json`
By populating the memory cache before loading the module, we can avoid a cycle
where a module is imported that is an overlay, which then triggers
ClangImporter, which then (redundantly) triggers the import of the overlay
module, which would reimport the module again, since it's import is still
underway and it hasn't been entered into the cache yet.
rdar://118846313
This PR refactors the ASTDumper to make it more structured, less mistake-prone, and more amenable to future changes. For example:
```cpp
// Before:
void visitUnresolvedDotExpr(UnresolvedDotExpr *E) {
printCommon(E, "unresolved_dot_expr")
<< " field '" << E->getName() << "'";
PrintWithColorRAII(OS, ExprModifierColor)
<< " function_ref=" << getFunctionRefKindStr(E->getFunctionRefKind());
if (E->getBase()) {
OS << '\n';
printRec(E->getBase());
}
PrintWithColorRAII(OS, ParenthesisColor) << ')';
}
// After:
void visitUnresolvedDotExpr(UnresolvedDotExpr *E, StringRef label) {
printCommon(E, "unresolved_dot_expr", label);
printFieldQuoted(E->getName(), "field");
printField(E->getFunctionRefKind(), "function_ref", ExprModifierColor);
if (E->getBase()) {
printRec(E->getBase());
}
printFoot();
}
```
* Values are printed through calls to base class methods, rather than direct access to the underlying `raw_ostream`.
* These methods tend to reduce the chances of bugs like missing/extra spaces or newlines, too much/too little indentation, etc.
* More values are quoted, and unprintable/non-ASCII characters in quoted values are escaped before printing.
* Infrastructure to label child nodes now exists.
* Some weird breaks from the normal "style", like `PatternBindingDecl`'s original and processed initializers, have been brought into line.
* Some types that previously used ad-hoc dumping functions, like conformances and substitution maps, are now structured similarly to the dumper classes.
* I've fixed the odd dumping bug along the way. For example, distributed actors were only marked `actor`, not `distributed actor`.
This PR doesn't change the overall style of AST dumps; they're still pseudo-S-expressions. But the logic that implements this style is now isolated into a relatively small base class, making it feasible to introduce e.g. JSON dumping in the future.
This refactors DWARFImporter to become a part of ClangImporter, since
it needs access to many of its implementation details anyway. The
DWARFImporterDelegate is just another mechanism for deserializing
Clang ASTs and once we have a Clang AST, the processing is effectively
the same.
When debugging Objective-C or C++ code on Darwin, the debug info
collected by dsymutil in the .dSYM bundle is entirely
self-contained. It is possible to debug a program, set breakpoints and
print variables even without having the complete original source code
or a matching SDK available. With Swift, this is currently not the
case. Even though .dSYM bundles contain the binary .swiftmodule for
all Swift modules, any Clang modules that the Swift modules depend on,
still need to be imported from source to even get basic LLDB
functionality to work. If ClangImporter fails to import a Clang
module, effectively the entire Swift module depending on it gets
poisoned.
This patch is addressing this issue by introducing a ModuleLoader that
can ask queries about Clang Decls to LLDB, since LLDB knows how to
reconstruct Clang decls from DWARF and clang -gmodules producxes full
debug info for Clang modules that is embedded into the .dSYM budle.
This initial version does not contain any advanced functionality at
all, it merely produces an empty ModuleDecl. Intertestingly, even this
is a considerable improvement over the status quo. LLDB can now print
Swift-only variables in modules with failing Clang depenecies, and
becuase of fallback mechanisms that were implemented earlier, it can
even display the contents of pure Objective-C objects that are
imported into Swift. C structs obviously don't work yet.
rdar://problem/36032653
