[Expression parser] Setting to enable use of ExternalASTMerger
This setting can be enabled like this at the target level:
(lldb) settings set target.experimental.use-modern-type-lookup true
This causes several new behaviors in the Clang expression parser:
- It completely disables use of ClangASTImporter. None are created
at all, and all users of it are now conditionalized on its
presence.
- It instead constructs a per-expression ExternalASTMerger, which
exists inside Clang and contains much of the type completion
logic that hitherto lived in ExternalASTSource,
ClangExpressionDeclMap, and ClangASTImporter.
- The expression parser uses this Merger as a backend for copying
and completing types.
- It also constructs a persistent ExternalASTMerger which is
connected to the Target's persistent AST context.
This is a major chunk of LLDB functionality moved into Clang. It
can be tested in two ways:
1. For an individual debug session, enable the setting before
running a target.
2. For the testsuite, change the option to be default-true. This
is done in Target.cpp's g_experimental_properties. The
testsuite is not yet clean with this, so I have not committed
that switch.
I have filed a Bugzilla for extending the testsuite to allow
custom settings for all tests:
https://bugs.llvm.org/show_bug.cgi?id=34771
I have also filed a Bugzilla for fixing the remaining testsuite
failures with this setting enabled:
https://bugs.llvm.org/show_bug.cgi?id=34772
llvm-svn: 314458
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
index 4e20be7..f7b686f 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
@@ -526,7 +526,7 @@
if (decl_map) {
llvm::IntrusiveRefCntPtr<clang::ExternalASTSource> ast_source(
decl_map->CreateProxy());
- decl_map->InstallASTContext(ast_context.get());
+ decl_map->InstallASTContext(*ast_context, m_compiler->getFileManager());
ast_context->setExternalSource(ast_source);
}