[Lldb-commits] [lldb] [LLDB] Fix crash in TypeSystemClang::GetIndexofChildMemberWithName. (PR #117808)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: None (cmtice)

<details>
<summary>Changes</summary>

LLDB can crash in TypeSystemClang::GetIndexOfChildMemberWithName, at a point where it pushes an index onto the child_indexes vector, tries to call itself recursively, then tries to pop the entry from child_indexes. The problem is that the recursive call can clear child_indexes, so that this code ends up trying to pop an already empty vector.  This change saves the old vector before the push, then restores the saved vector rather than trying to pop.

---
Full diff: https://github.com/llvm/llvm-project/pull/117808.diff


1 Files Affected:

- (modified) lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp (+2-2) 


``````````diff
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index 1a77c7cf9161a0..16eca7700d9fff 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -6754,12 +6754,12 @@ size_t TypeSystemClang::GetIndexOfChildMemberWithName(
           llvm::StringRef field_name = field->getName();
           if (field_name.empty()) {
             CompilerType field_type = GetType(field->getType());
+            std::vector<uint32_t> save_indices = child_indexes;
             child_indexes.push_back(child_idx);
             if (field_type.GetIndexOfChildMemberWithName(
                     name, omit_empty_base_classes, child_indexes))
               return child_indexes.size();
-            child_indexes.pop_back();
-
+            child_indexes = save_indices;
           } else if (field_name == name) {
             // We have to add on the number of base classes to this index!
             child_indexes.push_back(

``````````

</details>


https://github.com/llvm/llvm-project/pull/117808