[Lldb-commits] [lldb] [lldb][windows] fix unchecked Expected (PR #178681)

[Charles Zablit via lldb-commits]

https://github.com/charles-zablit created https://github.com/llvm/llvm-project/pull/178681

This patch fixes unchecked `Expected<T>` returns from the `CompilerType::GetByteSize` method.

>From 095e0da54146f91e0877e3be8b86e9df7a6c0ab5 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 29 Jan 2026 15:26:04 +0000
Subject: [PATCH] [lldb][windows] fix unchecked Expected

---
 .../include/lldb/Target/ProcessStructReader.h | 28 +++++++++++++------
 .../TypeSystem/Clang/TypeSystemClang.cpp      | 14 ++++++----
 lldb/source/ValueObject/ValueObject.cpp       |  4 +--
 3 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/lldb/include/lldb/Target/ProcessStructReader.h b/lldb/include/lldb/Target/ProcessStructReader.h
index 0f0b3f69d5509..df3203698afd0 100644
--- a/lldb/include/lldb/Target/ProcessStructReader.h
+++ b/lldb/include/lldb/Target/ProcessStructReader.h
@@ -16,6 +16,7 @@
 #include "lldb/Target/Process.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/DataExtractor.h"
+#include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Status.h"
 
 #include "llvm/ADT/StringMap.h"
@@ -59,21 +60,32 @@ class ProcessStructReader {
       // no support for bitfields in here (yet)
       if (is_bitfield)
         return;
-      auto size = field_type.GetByteSize(nullptr);
+      auto size_or_err = field_type.GetByteSize(nullptr);
+      if (!size_or_err) {
+        LLDB_LOG_ERROR(GetLog(LLDBLog::Target), size_or_err.takeError(), "{0}");
+        return;
+      }
+      size_t size = *size_or_err;
+
       // no support for things larger than a uint64_t (yet)
-      if (!size || *size > 8)
+      if (size > 8)
         return;
       size_t byte_index = static_cast<size_t>(bit_offset / 8);
-      m_fields.insert({name, FieldImpl{field_type, byte_index,
-                                       static_cast<size_t>(*size)}});
+      m_fields.insert(
+          {name, FieldImpl{field_type, byte_index, static_cast<size_t>(size)}});
     }
-    auto total_size = struct_type.GetByteSize(nullptr);
-    if (!total_size)
+    auto total_size_or_err = struct_type.GetByteSize(nullptr);
+    if (!total_size_or_err) {
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Target), total_size_or_err.takeError(),
+                     "{0}");
       return;
-    lldb::WritableDataBufferSP buffer_sp(new DataBufferHeap(*total_size, 0));
+    }
+    size_t total_size = *total_size_or_err;
+
+    lldb::WritableDataBufferSP buffer_sp(new DataBufferHeap(total_size, 0));
     Status error;
     process->ReadMemoryFromInferior(base_addr, buffer_sp->GetBytes(),
-                                    *total_size, error);
+                                    total_size, error);
     if (error.Fail())
       return;
     m_data = DataExtractor(buffer_sp, m_byte_order, m_addr_byte_size);
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index 34d97a07d73fc..478f10a60a865 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -885,11 +885,15 @@ lldb::BasicType TypeSystemClang::GetBasicTypeEnumeration(llvm::StringRef name) {
 }
 
 uint32_t TypeSystemClang::GetPointerByteSize() {
-  if (m_pointer_byte_size == 0)
-    if (auto size = GetBasicType(lldb::eBasicTypeVoid)
-                        .GetPointerType()
-                        .GetByteSize(nullptr))
-      m_pointer_byte_size = *size;
+  if (m_pointer_byte_size != 0)
+    return m_pointer_byte_size;
+  auto size_or_err =
+      GetBasicType(lldb::eBasicTypeVoid).GetPointerType().GetByteSize(nullptr);
+  if (!size_or_err) {
+    LLDB_LOG_ERROR(GetLog(LLDBLog::Types), size_or_err.takeError(), "{0}");
+    return m_pointer_byte_size;
+  }
+  m_pointer_byte_size = *size_or_err;
   return m_pointer_byte_size;
 }
 
diff --git a/lldb/source/ValueObject/ValueObject.cpp b/lldb/source/ValueObject/ValueObject.cpp
index 121054e3e92ed..9c453e06b1c31 100644
--- a/lldb/source/ValueObject/ValueObject.cpp
+++ b/lldb/source/ValueObject/ValueObject.cpp
@@ -744,8 +744,8 @@ size_t ValueObject::GetPointeeData(DataExtractor &data, uint32_t item_idx,
       }
     } break;
     case eAddressTypeHost: {
-      auto max_bytes =
-          GetCompilerType().GetByteSize(exe_ctx.GetBestExecutionContextScope());
+      auto max_bytes = llvm::expectedToOptional(GetCompilerType().GetByteSize(
+          exe_ctx.GetBestExecutionContextScope()));
       if (max_bytes && *max_bytes > offset) {
         size_t bytes_read = std::min<uint64_t>(*max_bytes - offset, bytes);
         addr = m_value.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);