[lldb] Fix using self in expression evaluation when self is weakly captured

This both fixes printing self when multiple self variables are present (for
example, "guard let self = self"), as well as referencing self
properties without spelling out self ("self.a" vs "a") when self is
captured weakly in closures.

rdar://122956043

Author: augusto2112

lldb/source/Plugins/ExpressionParser/Swift/SwiftUserExpression.cpp

@@ -224,26 +224,34 @@ void SwiftUserExpression::ScanContext(ExecutionContext &exe_ctx, Status &err) {
 
   LLDB_LOG(log, "  [SUE::SC] Compilation unit is swift");
 
-  Block *function_block = sym_ctx.GetFunctionBlock();
-  if (!function_block) {
-    LLDB_LOG(log, "  [SUE::SC] No function block");
+  Block *innermost_block = sym_ctx.block;
+  if (!innermost_block) {
+    LLDB_LOG(log, "  [SUE::SC] No block");
     return;
   }
 
-  lldb::VariableListSP variable_list_sp(
-      function_block->GetBlockVariableList(true));
-  if (!variable_list_sp) {
-    LLDB_LOG(log, "  [SUE::SC] No block variable list");
+  VariableList variable_list;
+  innermost_block->AppendVariables(/*can_create*/
+                                   true,
+                                   /*get_parent_variables*/ true,
+                                   /*stop_if_block_is_inlined_function*/ false,
+                                   /*filter*/
+                                   [&](Variable *var) {
+                                     if (!variable_list.Empty())
+                                       return false;
+                                     return SwiftLanguageRuntime::IsSelf(*var);
+                                   },
+                                   &variable_list);
+
+  if (variable_list.Empty()) {
+    LLDB_LOG(log, "  [SUE::SC] No self variable");
     return;
   }
 
-  lldb::VariableSP self_var_sp(
-      variable_list_sp->FindVariable(ConstString("self")));
-  if (!self_var_sp || !SwiftLanguageRuntime::IsSelf(*self_var_sp)) {
-    LLDB_LOG(log, "  [SUE::SC] No valid `self` variable");
-    return;
-  }
+  assert(variable_list.GetSize() == 1 && variable_list.GetVariableAtIndex(0) &&
+         "Unexpected variable list state");
 
+  lldb::VariableSP self_var_sp = variable_list.GetVariableAtIndex(0);
   // If we have a self variable, but it has no location at the current PC, then
   // we can't use it.  Set the self var back to empty and we'll just pretend we
   // are in a regular frame, which is really the best we can do.

lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntimeDynamicTypeResolution.cpp

@@ -1563,7 +1563,8 @@ bool SwiftLanguageRuntime::IsSelf(Variable &variable) {
     return false;
   node_ptr = node_ptr->getFirstChild();
   return node_ptr->getKind() == swift::Demangle::Node::Kind::Constructor ||
-         node_ptr->getKind() == swift::Demangle::Node::Kind::Allocator;
+         node_ptr->getKind() == swift::Demangle::Node::Kind::Allocator ||
+         node_ptr->getKind() == swift::Demangle::Node::Kind::ExplicitClosure;
 }
 
 static swift::Demangle::NodePointer

lldb/test/API/lang/swift/expression/weak_self/TestWeakSelf.py

@@ -9,7 +9,39 @@
 # See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 #
 # ------------------------------------------------------------------------------
-import lldbsuite.test.lldbinline as lldbinline
-from lldbsuite.test.decorators import *
+#
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *	
+import lldbsuite.test.lldbutil as lldbutil
+
+
+
+class TestSwiftGenericExtension(TestBase):
+     @swiftTest
+     def test(self):
+        self.build()
+
+        target, process, _, _ = lldbutil.run_to_source_breakpoint(
+             self, "break here for if let success", lldb.SBFileSpec("main.swift")
+         )
+        self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["ClosureMaker)", "5"])
+        self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["ClosureMaker)", "5"])
+        self.expect("expr a", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["5"])
+
+        breakpoint = target.BreakpointCreateBySourceRegex(
+            'break here for guard let success', lldb.SBFileSpec('main.swift'), None)
+        lldbutil.continue_to_breakpoint(process, breakpoint)
+        self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["ClosureMaker)", "5"])
+        self.expect("expr a", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["5"])
+
+
+        breakpoint = target.BreakpointCreateBySourceRegex(
+            'break here for if let else', lldb.SBFileSpec('main.swift'), None)
+        lldbutil.continue_to_breakpoint(process, breakpoint)
+        self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["nil"])
 
-lldbinline.MakeInlineTest(__file__, globals(), decorators=[swiftTest])
+        breakpoint = target.BreakpointCreateBySourceRegex(
+            'break here for guard let else', lldb.SBFileSpec('main.swift'), None)
+        lldbutil.continue_to_breakpoint(process, breakpoint)
+        self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["nil"])

lldb/test/API/lang/swift/expression/weak_self/main.swift

@@ -19,22 +19,20 @@ class ClosureMaker {
 
   func getClosure() -> (() -> Int) {
     return { [weak self] () -> Int in
-             if let _self = self {
-               return _self.a //% self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["ClosureMaker?)", "5"])
-                              //% self.expect("expr self!", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["ClosureMaker)", "5"])
+             if let self = self {
+               return self.a // break here for if let success
              } else {
-               return 0 //% self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["nil"])
+               return 0 // break here for if let else
             }
           }
   }
 
   func getGuardClosure() -> (() -> Int) {
     return { [weak self] () -> Int in
              guard let self = self else {
-               return 0  //% self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["nil"])
+               return 0 // break here for guard let else
              }
-             return self.a //% self.expect("expr self", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["ClosureMaker?)", "5"])
-                          //% self.expect("expr self!", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["ClosureMaker)", "5"])
+             return self.a // break here for guard let success
           }
   }
 }