[lldb] Add support for calling objc_direct methods from LLDB's expression evaluator.

Summary:
D69991 introduced `__attribute__((objc_direct))` that allows directly calling methods without message passing.
This patch adds support for calling methods with this attribute to LLDB's expression evaluator.

The patch can be summarised in that LLDB just adds the same attribute to our module AST when we find a
method with `__attribute__((objc_direct))` in our debug information.

Reviewers: aprantl, shafik

Reviewed By: shafik

Subscribers: JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71196

1 files changed, 13 insertions, 1 deletions

diff --git a/lldb/source/Symbol/ClangASTContext.cpp b/lldb/source/Symbol/ClangASTContext.cpp
index 95bb4551f2c..3b6b0db3449 100644
--- a/lldb/source/Symbol/ClangASTContext.cpp
+++ b/lldb/source/Symbol/ClangASTContext.cpp
@@ -7769,7 +7769,7 @@ clang::ObjCMethodDecl *ClangASTContext::AddMethodToObjCObjectType(
                       // (lldb::opaque_compiler_type_t type, "-[NString
                       // stringWithCString:]")
     const CompilerType &method_clang_type, lldb::AccessType access,
-    bool is_artificial, bool is_variadic) {
+    bool is_artificial, bool is_variadic, bool is_objc_direct_call) {
   if (!type || !method_clang_type.IsValid())
     return nullptr;
 
@@ -7875,6 +7875,18 @@ clang::ObjCMethodDecl *ClangASTContext::AddMethodToObjCObjectType(
         llvm::ArrayRef<clang::SourceLocation>());
   }
 
+  if (is_objc_direct_call) {
+    // Add a the objc_direct attribute to the declaration we generate that
+    // we generate a direct method call for this ObjCMethodDecl.
+    objc_method_decl->addAttr(
+        clang::ObjCDirectAttr::CreateImplicit(*ast, SourceLocation()));
+    // Usually Sema is creating implicit parameters (e.g., self) when it
+    // parses the method. We don't have a parsing Sema when we build our own
+    // AST here so we manually need to create these implicit parameters to
+    // make the direct call code generation happy.
+    objc_method_decl->createImplicitParams(*ast, class_interface_decl);
+  }
+
   class_interface_decl->addDecl(objc_method_decl);
 
 #ifdef LLDB_CONFIGURATION_DEBUG