Merge pull request swiftlang#7493 from augusto2112/5.9-dont-cache-parse

[lldb] Mark parsing Swift expressions with generics as not cacheable

Author: adrian-prantl

lldb/include/lldb/Expression/UserExpression.h

@@ -192,6 +192,8 @@ class UserExpression : public Expression {
   /// expression.  Text() should contain the definition of this function.
   const char *FunctionName() override { return "$__lldb_expr"; }
 
+  /// Returns whether the call to Parse on this user expression is cacheable.
+  virtual bool IsParseCacheable() { return true; }
   /// Return the language that should be used when parsing.  To use the
   /// default, return eLanguageTypeUnknown.
   lldb::LanguageType Language() const override { return m_language; }

lldb/source/Breakpoint/BreakpointLocation.cpp

@@ -250,6 +250,7 @@ bool BreakpointLocation::ConditionSaysStop(ExecutionContext &exe_ctx,
   DiagnosticManager diagnostics;
 
   if (condition_hash != m_condition_hash || !m_user_expression_sp ||
+      !m_user_expression_sp->IsParseCacheable() ||
       !m_user_expression_sp->MatchesContext(exe_ctx)) {
     LanguageType language = eLanguageTypeUnknown;
     // See if we can figure out the language from the frame, otherwise use the

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

@@ -1725,6 +1725,16 @@ SwiftExpressionParser::Parse(DiagnosticManager &diagnostic_manager,
     return ParseResult::unrecoverable_error;
   }
 
+  // If any generics are present, this expression is not parseable.
+  if (parsed_expr->code_manipulator)
+    m_is_cacheable =
+        !llvm::any_of(parsed_expr->code_manipulator->GetVariableInfo(),
+                      [](const auto &variable) {
+                        return variable.IsMetadataPointer() ||
+                               variable.IsPackCount() ||
+                               variable.IsUnboundPack();
+                      });
+
   auto dumpModule = [&](const char *msg) {
     std::string s;
     llvm::raw_string_ostream ss(s);

lldb/source/Plugins/ExpressionParser/Swift/SwiftExpressionParser.h

@@ -97,6 +97,11 @@ class SwiftExpressionParser : public ExpressionParser {
   ParseResult Parse(DiagnosticManager &diagnostic_manager,
                     uint32_t first_line = 0, uint32_t last_line = UINT32_MAX);
 
+  /// Returns true if the call to parse of this type is cacheable.
+  bool IsParseCacheable() const {
+    return m_is_cacheable;
+  }
+
   //------------------------------------------------------------------
   /// Ready an already-parsed expression for execution, possibly
   /// evaluating it statically.
@@ -198,6 +203,9 @@ class SwiftExpressionParser : public ExpressionParser {
 
   /// If true, we are running in REPL mode
   EvaluateExpressionOptions m_options;
+
+  /// Indicates whether the call to Parse of this type is cacheable.
+  bool m_is_cacheable;
 };
 } // namespace lldb_private
 

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

@@ -139,6 +139,10 @@ class SwiftUserExpression : public LLVMUserExpression {
   void WillStartExecuting() override;
   void DidFinishExecuting() override;
 
+  bool IsParseCacheable() override {
+    return m_parser->IsParseCacheable();
+  }
+
 private:
   //------------------------------------------------------------------
   /// Populate m_in_cplusplus_method and m_in_objectivec_method based on the

lldb/test/API/lang/swift/archetype_in_cond_breakpoint/TestArchetypeInConditionalBreakpoint.py

@@ -7,28 +7,43 @@
 
 class TestArchetypeInConditionalBreakpoint(TestBase):
     @swiftTest
-    def test_stops(self):
+    def test_stops_free_function(self):
+        self.stops("break here for free function")
+
+    @swiftTest
+    def test_doesnt_stop_free_function(self):
+        self.doesnt_stop("break here for free function")
+
+    @swiftTest
+    def test_stops_class(self):
+        self.stops("break here for class")
+
+    @swiftTest
+    def test_doesnt_stop_class(self):
+        self.doesnt_stop("break here for class")
+
+    def stops(self, breakpoint_string):
         """Tests that using archetypes in a conditional breakpoint's expression works correctly"""
         self.build()
         target = lldbutil.run_to_breakpoint_make_target(self)
 
         breakpoint = target.BreakpointCreateBySourceRegex(
-            "break here", lldb.SBFileSpec("main.swift")
+            breakpoint_string, lldb.SBFileSpec("main.swift")
         )
 
         breakpoint.SetCondition("T.self == Int.self")
         _, process, _, _ = lldbutil.run_to_breakpoint_do_run(self, target, breakpoint)
 
         self.assertEqual(process.state, lldb.eStateStopped)
+        self.expect("expression T.self", substrs=["Int"])
 
-    @swiftTest
-    def test_doesnt_stop(self):
+    def doesnt_stop(self, breakpoint_string):
         """Tests that using archetypes in a conditional breakpoint's expression works correctly"""
         self.build()
         target = lldbutil.run_to_breakpoint_make_target(self)
 
         breakpoint = target.BreakpointCreateBySourceRegex(
-            "break here", lldb.SBFileSpec("main.swift")
+            breakpoint_string, lldb.SBFileSpec("main.swift")
         )
 
         breakpoint.SetCondition("T.self == Double.self")

lldb/test/API/lang/swift/archetype_in_cond_breakpoint/main.swift

@@ -1,4 +1,18 @@
+
 func f<T>(t: T) {
-  print(1) // break here
+  print(1) // break here for free function
 }
+f(t: "This is a string")
+f(t: "This is another string")
+f(t: true)
 f(t: 5)
+
+class MyClass<T> {
+  func f() {
+    print(1) // break here for class
+  }
+}
+MyClass<String>().f()
+MyClass<String>().f()
+MyClass<Bool>().f()
+MyClass<Int>().f()