[lldb] Add a progress event for executing an expression

Expressions can take arbitrary amounts of time to run, so IDEs might
want to be informed about the fact that an expression is currently
being executed.

rdar://141253078

Author: adrian-prantl

lldb/source/Expression/FunctionCaller.cpp

@@ -8,6 +8,7 @@
 
 #include "lldb/Expression/FunctionCaller.h"
 #include "lldb/Core/Module.h"
+#include "lldb/Core/Progress.h"
 #include "lldb/Expression/DiagnosticManager.h"
 #include "lldb/Expression/IRExecutionUnit.h"
 #include "lldb/Interpreter/CommandReturnObject.h"
@@ -338,6 +339,10 @@ lldb::ExpressionResults FunctionCaller::ExecuteFunction(
     DiagnosticManager &diagnostic_manager, Value &results) {
   lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
 
+  Debugger *debugger =
+      exe_ctx.GetTargetPtr() ? &exe_ctx.GetTargetPtr()->GetDebugger() : nullptr;
+  Progress progress("Calling function", FunctionName(), {}, debugger);
+
   // FunctionCaller::ExecuteFunction execution is always just to get the
   // result. Unless explicitly asked for, ignore breakpoints and unwind on
   // error.

lldb/source/Expression/UserExpression.cpp

@@ -14,6 +14,7 @@
 #include <string>
 
 #include "lldb/Core/Module.h"
+#include "lldb/Core/Progress.h"
 #include "lldb/Expression/DiagnosticManager.h"
 #include "lldb/Expression/ExpressionVariable.h"
 #include "lldb/Expression/IRExecutionUnit.h"
@@ -424,6 +425,18 @@ UserExpression::Execute(DiagnosticManager &diagnostic_manager,
                         const EvaluateExpressionOptions &options,
                         lldb::UserExpressionSP &shared_ptr_to_me,
                         lldb::ExpressionVariableSP &result_var) {
+  Debugger *debugger =
+      exe_ctx.GetTargetPtr() ? &exe_ctx.GetTargetPtr()->GetDebugger() : nullptr;
+  std::string details;
+  if (m_options.IsForUtilityExpr())
+    details = "LLDB utility";
+  else if (m_expr_text.size() > 15)
+    details = m_expr_text.substr(0, 14) + "…";
+  else
+    details = m_expr_text;
+
+  Progress progress("Running expression", details, {}, debugger);
+
   lldb::ExpressionResults expr_result = DoExecute(
       diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var);
   Target *target = exe_ctx.GetTargetPtr();

lldb/test/Shell/Expr/TestExecProgress.test

@@ -0,0 +1,8 @@
+# RUN: %lldb -s %s  | FileCheck %s
+log enable lldb event
+expr 1
+expr 1 // And a very long comment.
+quit
+
+# CHECK: {{title = "Running expression", details = "1"}}
+# CHECK: {{title = "Running expression", details = "1 // And a ver…"}}