1 files changed, 48 insertions, 7 deletions

diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
index 2fc690e3d5b..0bc664c93f8 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
@@ -8,6 +8,9 @@
 
 #include "ClangExpressionSourceCode.h"
 
+#include "clang/Basic/CharInfo.h"
+#include "llvm/ADT/StringRef.h"
+
 #include "Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.h"
 #include "Plugins/ExpressionParser/Clang/ClangPersistentVariables.h"
 #include "lldb/Symbol/Block.h"
@@ -161,8 +164,43 @@ static void AddMacros(const DebugMacros *dm, CompileUnit *comp_unit,
   }
 }
 
+/// Checks if the expression body contains the given variable as a token.
+/// \param body The expression body.
+/// \param var The variable token we are looking for.
+/// \return True iff the expression body containes the variable as a token.
+static bool ExprBodyContainsVar(llvm::StringRef body, llvm::StringRef var) {
+  assert(var.find_if([](char c) { return !clang::isIdentifierBody(c); }) ==
+             llvm::StringRef::npos &&
+         "variable contains non-identifier chars?");
+
+  size_t start = 0;
+  // Iterate over all occurences of the variable string in our expression.
+  while ((start = body.find(var, start)) != llvm::StringRef::npos) {
+    // We found our variable name in the expression. Check that the token
+    // that contains our needle is equal to our variable and not just contains
+    // the character sequence by accident.
+    // Prevents situations where we for example inlcude the variable 'FOO' in an
+    // expression like 'FOObar + 1'.
+    bool has_characters_before =
+        start != 0 && clang::isIdentifierBody(body[start - 1]);
+    bool has_characters_after =
+        start + var.size() < body.size() &&
+        clang::isIdentifierBody(body[start + var.size()]);
+
+    // Our token just contained the variable name as a substring. Continue
+    // searching the rest of the expression.
+    if (has_characters_before || has_characters_after) {
+      ++start;
+      continue;
+    }
+    return true;
+  }
+  return false;
+}
+
 static void AddLocalVariableDecls(const lldb::VariableListSP &var_list_sp,
-                                  StreamString &stream) {
+                                  StreamString &stream,
+                                  const std::string &expr) {
   for (size_t i = 0; i < var_list_sp->GetSize(); i++) {
     lldb::VariableSP var_sp = var_list_sp->GetVariableAtIndex(i);
 
@@ -170,15 +208,17 @@ static void AddLocalVariableDecls(const lldb::VariableListSP &var_list_sp,
     if (!var_name || var_name == "this" || var_name == ".block_descriptor")
       continue;
 
+    if (!expr.empty() && !ExprBodyContainsVar(expr, var_name.GetStringRef()))
+      continue;
+
     stream.Printf("using $__lldb_local_vars::%s;\n", var_name.AsCString());
   }
 }
 
-bool ClangExpressionSourceCode::GetText(std::string &text,
-                                   lldb::LanguageType wrapping_language,
-                                   bool static_method,
-                                   ExecutionContext &exe_ctx, bool add_locals,
-                                   llvm::ArrayRef<std::string> modules) const {
+bool ClangExpressionSourceCode::GetText(
+    std::string &text, lldb::LanguageType wrapping_language, bool static_method,
+    ExecutionContext &exe_ctx, bool add_locals, bool force_add_all_locals,
+    llvm::ArrayRef<std::string> modules) const {
   const char *target_specific_defines = "typedef signed char BOOL;\n";
   std::string module_macros;
 
@@ -256,7 +296,8 @@ bool ClangExpressionSourceCode::GetText(std::string &text,
         if (target->GetInjectLocalVariables(&exe_ctx)) {
           lldb::VariableListSP var_list_sp =
               frame->GetInScopeVariableList(false, true);
-          AddLocalVariableDecls(var_list_sp, lldb_local_var_decls);
+          AddLocalVariableDecls(var_list_sp, lldb_local_var_decls,
+                                force_add_all_locals ? "" : m_body);
         }
       }
     }