Commit Graph

6 Commits

Author SHA1 Message Date
Raphael Isemann 019bd6485c [lldb] Don't complete ObjCInterfaceDecls in ClangExternalASTSourceCallbacks::FindExternalVisibleDeclsByName
Summary:
For ObjCInterfaceDecls, LLDB iterates over the `methods` of the interface in FindExternalVisibleDeclsByName
since commit ef423a3ba5 .
However, when LLDB calls `oid->methods()` in that function, Clang will pull in all declarations in the current
DeclContext from the current ExternalASTSource (which is again, `ClangExternalASTSourceCallbacks`). The
reason for that is that `methods()` is just a wrapper for `decls()` which is supposed to provide a list of *all*
(both currently loaded and external) decls in the DeclContext.

However, `ClangExternalASTSourceCallbacks::FindExternalLexicalDecls` doesn't implement support for ObjCInterfaceDecl,
so we don't actually add any declarations and just mark the ObjCInterfaceDecl as having no ExternalLexicalStorage.

As LLDB uses the ExternalLexicalStorage to see if it can complete a type with the ExternalASTSource, this causes
that LLDB thinks our class can't be completed any further by the ExternalASTSource
and will from on no longer make any CompleteType/FindExternalLexicalDecls calls to that decl. This essentially
renders those types unusable in the expression parser as they will always be considered incomplete.

This patch just changes the call to `methods` (which is just a `decls()` wrapper), to some ad-hoc `noload_methods`
call which is wrapping `noload_decls()`. `noload_decls()` won't trigger any calls to the ExternalASTSource, so
this prevents that ExternalLexicalStorage will be set to false.

The test for this is just adding a method to an ObjC interface. Before this patch, this unset the ExternalLexicalStorage
flag and put the interface into the state described above.

In a normal user session this situation was triggered by setting a breakpoint in a method of some ObjC class. This
caused LLDB to create the MethodDecl for that specific method and put it into the the ObjCInterfaceDecl.
Also `ObjCLanguageRuntime::LookupInCompleteClassCache` needs to be unable to resolve the type do
an actual definition when the breakpoint is set (I'm not sure how exactly this can happen, but we just
found no Type instance that had the `TypePayloadClang::IsCompleteObjCClass` flag set in its payload in
the situation where this happens. This however doesn't seem to be a regression as logic wasn't changed
from what I can see).

The module-ownership.mm test had to be changed as the only reason why the ObjC interface in that test had
it's ExternalLexicalStorage flag set to false was because of this unintended side effect. What actually happens
in the test is that ExternalLexicalStorage is first set to false in `DWARFASTParserClang::CompleteTypeFromDWARF`
when we try to complete the `SomeClass` interface, but is then the flag is set back to true once we add
the last ivar of `SomeClass` (see `SetMemberOwningModule` in `TypeSystemClang.cpp` which is called
when we add the ivar). I'll fix the code for that in a follow-up patch.

I think some of the code here needs some rethinking. LLDB and Clang shouldn't infer anything about the ExternalASTSource
and its ability to complete the current type form the `ExternalLexicalStorage` flag. We probably should
also actually provide any declarations when we get asked for the lexical decls of an ObjCInterfaceDecl. But both of those
changes are bigger (and most likely would cause us to eagerly complete more types), so those will be follow up patches
and this patch just brings us back to the state before commit ef423a3ba5 .

Fixes rdar://63584164

Reviewers: aprantl, friss, shafik

Reviewed By: aprantl, shafik

Subscribers: arphaman, abidh, JDevlieghere

Differential Revision: https://reviews.llvm.org/D80556
2020-05-27 12:39:24 +02:00
Adrian Prantl ef423a3ba5 Add Objective-C property accessors loaded from Clang module DWARF to lookup
This patch fixes a bug when synthesizing an ObjC property from
-gmodules debug info. Because the method declaration that is injected
via the non-modular property implementation is not added to the
ObjCInterfaceDecl's lookup pointer, a second copy of the accessor
would be generated when processing the ObjCPropertyDecl. This can be
avoided by finding the existing method decl in
ClangExternalASTSourceCallbacks::FindExternalVisibleDeclsByName() and
adding it to the LookupPtr.

Differential Revision: https://reviews.llvm.org/D78333
2020-04-24 11:10:50 -07:00
Adrian Prantl 143d507c9f Preserve the owning module information from DWARF in the synthesized AST
Types that came from a Clang module are nested in DW_TAG_module tags
in DWARF. This patch recreates the Clang module hierarchy in LLDB and
1;95;0csets the owning module information accordingly. My primary motivation
is to facilitate looking up per-module APINotes for individual
declarations, but this likely also has other applications.

This reapplies the previously reverted commit, but without support for
ClassTemplateSpecializations, which I'm going to look into separately.

rdar://problem/59634380

Differential Revision: https://reviews.llvm.org/D75488
2020-04-09 11:09:44 -07:00
Adrian Prantl 32672b877d Revert "Preserve the owning module information from DWARF in the synthesized AST"
This reverts commit 4354dfbdf5 while investigating bot fallout.
2020-04-01 18:58:11 -07:00
Adrian Prantl 4354dfbdf5 Preserve the owning module information from DWARF in the synthesized AST
Types that came from a Clang module are nested in DW_TAG_module tags
in DWARF. This patch recreates the Clang module hierarchy in LLDB and
sets the owning module information accordingly. My primary motivation
is to facilitate looking up per-module APINotes for individual
declarations, but this likely also has other applications.

rdar://problem/59634380

Differential Revision: https://reviews.llvm.org/D75488
2020-04-01 17:46:02 -07:00
Alex Langford 8be30215fe [lldb] Move clang-based files out of Symbol
Summary:
This change represents the move of ClangASTImporter, ClangASTMetadata,
ClangExternalASTSourceCallbacks, ClangUtil, CxxModuleHandler, and
TypeSystemClang from lldbSource to lldbPluginExpressionParserClang.h

This explicitly removes knowledge of clang internals from lldbSymbol,
moving towards a more generic core implementation of lldb.

Reviewers: JDevlieghere, davide, aprantl, teemperor, clayborg, labath, jingham, shafik

Subscribers: emaste, mgorny, arphaman, jfb, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73661
2020-01-31 12:20:10 -08:00