[Lldb-commits] [lldb] [lldb][LibCxx] Move incorrect nullptr check (PR #96635)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Michael Buch (Michael137)

<details>
<summary>Changes</summary>

Found this while skimming this code. Don't have a reproducible test case for this but the nullptr check should clearly occur before we try to dereference `location_sp`.

---
Full diff: https://github.com/llvm/llvm-project/pull/96635.diff


1 Files Affected:

- (modified) lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp (+4-1) 


``````````diff
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
index b0e6fb7d6f5af..0f9f93b727ce8 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -808,6 +808,9 @@ ExtractLibcxxStringInfo(ValueObject &valobj) {
       size = (layout == StringLayout::DSC) ? size_mode_value
                                            : ((size_mode_value >> 1) % 256);
 
+    if (!location_sp)
+      return {};
+
     // When the small-string optimization takes place, the data must fit in the
     // inline string buffer (23 bytes on x86_64/Darwin). If it doesn't, it's
     // likely that the string isn't initialized and we're reading garbage.
@@ -815,7 +818,7 @@ ExtractLibcxxStringInfo(ValueObject &valobj) {
     const std::optional<uint64_t> max_bytes =
         location_sp->GetCompilerType().GetByteSize(
             exe_ctx.GetBestExecutionContextScope());
-    if (!max_bytes || size > *max_bytes || !location_sp)
+    if (!max_bytes || size > *max_bytes)
       return {};
 
     return std::make_pair(size, location_sp);

``````````

</details>


https://github.com/llvm/llvm-project/pull/96635