[lldb] Fix dynamic_cast by no longer failing on variable without metadata

Summary:
Our IR rewriting infrastructure currently fails when it encounters a variable which has no metadata associated.
This causes dynamic_cast to fail as in this case IRForTarget considers the type info pointers ('@_ZTI...') to be
variables without associated metadata. As there are no variables for these internal variables, this is actually
not an error and dynamic_cast would work fine if we didn't throw this error.

This patch fixes this by removing this diagnostics code. In case we would actually hit a variable that has no
metadata (but is supposed to have), we still have the error in the expression log so this shouldn't make it
harder to diagnose any missing metadata errors.

This patch should fix dynamic_cast and also adds a bunch of test coverage to that language feature.

Fixes rdar://10813639

Reviewers: davide, labath

Reviewed By: labath

Subscribers: friss, labath, abidh, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D65932

llvm-svn: 368511

diff --git a/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/ExtBase.cpp b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/ExtBase.cpp
new file mode 100644 (file)
index 0000000..4fde4ec
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/ExtBase.cpp
@@ -0,0 +1,5 @@
+#include "ExtBase.h"
+
+char ExtBase::bar() {
+  return 'x';
+}

diff --git a/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/ExtBase.h b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/ExtBase.h
new file mode 100644 (file)
index 0000000..28e139d
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/ExtBase.h
@@ -0,0 +1,3 @@
+class ExtBase {
+  virtual char bar();
+};

diff --git a/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/Makefile b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/Makefile
new file mode 100644 (file)
index 0000000..e1afdbd
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/Makefile
@@ -0,0 +1,3 @@
+LEVEL = ../../../make
+CXX_SOURCES := main.cpp ExtBase.cpp
+include $(LEVEL)/Makefile.rules

diff --git a/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/TestDynamicCast.py b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/TestDynamicCast.py
new file mode 100644 (file)
index 0000000..4c9058c
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/TestDynamicCast.py
@@ -0,0 +1,3 @@
+from lldbsuite.test import lldbinline
+
+lldbinline.MakeInlineTest(__file__, globals(), [])

diff --git a/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/main.cpp b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/main.cpp
new file mode 100644 (file)
index 0000000..dd2a07b
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/cpp/dynamic_cast/main.cpp
@@ -0,0 +1,51 @@
+#include "ExtBase.h"
+
+class Base {
+public:
+  virtual char foo() {
+    return 'b';
+  }
+};
+
+class Derived : public Base {
+public:
+  char foo() override {
+    return 'd';
+  }
+};
+
+class NonOverrideDerived : public Base {
+};
+
+class ExtDerived : public ExtBase {
+public:
+  char bar() override {
+    return 'y';
+  }
+};
+
+int main() {
+  Derived d;
+  NonOverrideDerived d2;
+  Base *b = &d;
+  Base *real_base = new Base();
+  char c = dynamic_cast<Derived *>(b)->foo();
+
+  ExtDerived ext_d;
+  ExtBase *ext_b = &ext_d;
+  ExtBase *ext_real_base = new ExtBase();
+  c = dynamic_cast<ExtDerived *>(ext_b)->bar();
+
+
+  return 0; //% self.expect("expression dynamic_cast<class Derived *>(b) == (Derived*)b", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class Base *>(b) == (Base*)b", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class Derived *>(real_base) == nullptr", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class NonOverrideDerived *>(&d) == nullptr", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class ExtDerived *>(real_base) == nullptr", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class Derived *>(&d2) == nullptr", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class NonOverrideDerived *>(&d2) == (NonOverrideDerived *)&d2", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class Derived *>(&ext_d) == nullptr", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class ExtDerived *>(ext_b) == (class ExtDerived*)ext_b", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class ExtBase *>(ext_real_base) == (class ExtBase*)ext_real_base", substrs = ["bool", " = true"])
+            //% self.expect("expression dynamic_cast<class ExtDerived *>(ext_real_base) == nullptr", substrs = ["bool", " = true"])
+}

diff --git a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
index 8b526de..29d2bbf 100644 (file)
--- a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
@@ -1265,16 +1265,10 @@ bool IRForTarget::MaybeHandleVariable(Value *llvm_value_ptr) {
     clang::NamedDecl *named_decl = DeclForGlobal(global_variable);
 
     if (!named_decl) {
-      if (IsObjCSelectorRef(llvm_value_ptr))
-        return true;
-
-      if (!global_variable->hasExternalLinkage())
-        return true;
-
       LLDB_LOG(log, "Found global variable \"{0}\" without metadata",
                global_variable->getName());
 
-      return false;
+      return true;
     }
 
     llvm::StringRef name(named_decl->getName());