[lldb] Handle empty search string in "memory find"

Given that you'd never find empty string, just error.

Also add a test that an invalid expr generates an error.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D123793

1 files changed, 8 insertions, 3 deletions

diff --git a/lldb/source/Commands/CommandObjectMemory.cpp b/lldb/source/Commands/CommandObjectMemory.cpp
index b7b28bc..4e63802 100644
--- a/lldb/source/Commands/CommandObjectMemory.cpp
+++ b/lldb/source/Commands/CommandObjectMemory.cpp
@@ -1052,9 +1052,14 @@ protected:
 
     DataBufferHeap buffer;
 
-    if (m_memory_options.m_string.OptionWasSet())
-      buffer.CopyData(m_memory_options.m_string.GetStringValue());
-    else if (m_memory_options.m_expr.OptionWasSet()) {
+    if (m_memory_options.m_string.OptionWasSet()) {
+      llvm::StringRef str = m_memory_options.m_string.GetStringValue();
+      if (str.empty()) {
+        result.AppendError("search string must have non-zero length.");
+        return false;
+      }
+      buffer.CopyData(str);
+    } else if (m_memory_options.m_expr.OptionWasSet()) {
       StackFrame *frame = m_exe_ctx.GetFramePtr();
       ValueObjectSP result_sp;
       if ((eExpressionCompleted ==