[lldb] Add support for specifying language when setting watchpoint by expression

This is useful in contexts where you have multiple languages in play:
You may be stopped in a frame for language A, but want to set a watchpoint
with an expression using language B. The current way to do this is to
use the setting `target.language` while setting the watchpoint and
unset it after the watchpoint is set, but that's kind of clunky and
somewhat error-prone. This should add a better way to do this.

rdar://108202559

Differential Revision: https://reviews.llvm.org/D149111

1 files changed, 4 insertions, 2 deletions

diff --git a/lldb/source/Commands/CommandObjectWatchpoint.cpp b/lldb/source/Commands/CommandObjectWatchpoint.cpp
index 8b8c196..14180f9 100644
--- a/lldb/source/Commands/CommandObjectWatchpoint.cpp
+++ b/lldb/source/Commands/CommandObjectWatchpoint.cpp
@@ -835,8 +835,7 @@ corresponding to the byte size of the data type.");
     m_arguments.push_back(arg);
 
     // Absorb the '-w' and '-s' options into our option group.
-    m_option_group.Append(&m_option_watchpoint, LLDB_OPT_SET_ALL,
-                          LLDB_OPT_SET_1);
+    m_option_group.Append(&m_option_watchpoint, LLDB_OPT_SET_1, LLDB_OPT_SET_1);
     m_option_group.Finalize();
   }
 
@@ -990,6 +989,7 @@ public:
       : CommandObjectRaw(
             interpreter, "watchpoint set expression",
             "Set a watchpoint on an address by supplying an expression. "
+            "Use the '-l' option to specify the language of the expression. "
             "Use the '-w' option to specify the type of watchpoint and "
             "the '-s' option to specify the byte size to watch for. "
             "If no '-w' option is specified, it defaults to write. "
@@ -1083,6 +1083,8 @@ protected:
     options.SetKeepInMemory(false);
     options.SetTryAllThreads(true);
     options.SetTimeout(std::nullopt);
+    if (m_option_watchpoint.language_type != eLanguageTypeUnknown)
+      options.SetLanguage(m_option_watchpoint.language_type);
 
     ExpressionResults expr_result =
         target->EvaluateExpression(expr, frame, valobj_sp, options);