[Lldb-commits] [lldb] 7e89fb5 - [lldb] Fix logic bugs in BytecodeSyntheticChildren (#227483)

[via lldb-commits]

Author: Dave Lee
Date: 2026-09-30T09:46:33-07:00
New Revision: 7e89fb5d646ef2d4b18520a8300818b5b94ef587

URL: https://github.com/llvm/llvm-project/commit/7e89fb5d646ef2d4b18520a8300818b5b94ef587
DIFF: https://github.com/llvm/llvm-project/commit/7e89fb5d646ef2d4b18520a8300818b5b94ef587.diff

LOG: [lldb] Fix logic bugs in BytecodeSyntheticChildren (#227483)

Fix a pair of bugs in `BytecodeSyntheticChildren`.

1. Fix conditions that should compare with `>= 0` (not `> 0`)
2. Fix an inverted conditional when checking if a formatter implements
`@get_child_index`

Assisted-by: claude

Added: 
    

Modified: 
    lldb/source/DataFormatters/TypeSynthetic.cpp

Removed: 
    


################################################################################
diff  --git a/lldb/source/DataFormatters/TypeSynthetic.cpp b/lldb/source/DataFormatters/TypeSynthetic.cpp
index c144717cadbf9..16401049f93b8 100644
--- a/lldb/source/DataFormatters/TypeSynthetic.cpp
+++ b/lldb/source/DataFormatters/TypeSynthetic.cpp
@@ -368,14 +368,14 @@ BytecodeSyntheticChildren::FrontEnd::CalculateNumChildren() {
     if (*u <= UINT32_MAX)
       return *u;
   if (auto *i = std::get_if<int64_t>(&top)) {
-    if (*i > 0 && *i <= UINT32_MAX)
+    if (*i >= 0 && *i <= UINT32_MAX)
       return *i;
     return UINT32_MAX;
   }
   if (auto *ap = std::get_if<llvm::APSInt>(&top)) {
     if (ap->isRepresentableByInt64()) {
       int64_t v = ap->getExtValue();
-      if (v > 0 && v <= UINT32_MAX)
+      if (v >= 0 && v <= UINT32_MAX)
         return static_cast<uint32_t>(v);
     }
     return UINT32_MAX;
@@ -416,8 +416,8 @@ BytecodeSyntheticChildren::FrontEnd::GetChildAtIndex(uint32_t idx) {
 
 llvm::Expected<size_t>
 BytecodeSyntheticChildren::FrontEnd::GetIndexOfChildWithName(ConstString name) {
-  if (m_impl.get_child_index)
-    return -1;
+  if (!m_impl.get_child_index)
+    return llvm::createStringErrorV("type has no child named '{0}'", name);
 
   FormatterBytecode::ControlStack control = {
       m_impl.get_child_index->getBuffer()};
@@ -439,14 +439,14 @@ BytecodeSyntheticChildren::FrontEnd::GetIndexOfChildWithName(ConstString name) {
     if (*u <= SIZE_MAX)
       return *u;
   if (auto *i = std::get_if<int64_t>(&top)) {
-    if (*i > 0 && static_cast<uint64_t>(*i) <= SIZE_MAX)
+    if (*i >= 0 && static_cast<uint64_t>(*i) <= SIZE_MAX)
       return *i;
     return SIZE_MAX;
   }
   if (auto *ap = std::get_if<llvm::APSInt>(&top)) {
     if (ap->isRepresentableByInt64()) {
       int64_t v = ap->getExtValue();
-      if (v > 0 && static_cast<uint64_t>(v) <= SIZE_MAX)
+      if (v >= 0 && static_cast<uint64_t>(v) <= SIZE_MAX)
         return static_cast<size_t>(v);
     }
     return SIZE_MAX;