[Lldb-commits] [lldb] [lldb-dap] Add feature to remember last non-empty expression. (PR #107485)

[via lldb-commits]

https://github.com/cmtice updated https://github.com/llvm/llvm-project/pull/107485

>From 15541f354decf80586d590db9f9cb353be04b122 Mon Sep 17 00:00:00 2001
From: Caroline Tice <cmtice at google.com>
Date: Thu, 5 Sep 2024 15:51:35 -0700
Subject: [PATCH 1/2] [lldb-dap] Add feature to remember last non-empty
 expression.

Update lldb-dap so if the user just presses return, which sends an
empty expression, it re-evaluates the most recent non-empty
expression/command. Also udpated test to test this case.
---
 lldb/test/API/tools/lldb-dap/evaluate/TestDAP_evaluate.py | 3 +++
 lldb/tools/lldb-dap/lldb-dap.cpp                          | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/lldb/test/API/tools/lldb-dap/evaluate/TestDAP_evaluate.py b/lldb/test/API/tools/lldb-dap/evaluate/TestDAP_evaluate.py
index 29548a835c6919..9ed0fc564268a7 100644
--- a/lldb/test/API/tools/lldb-dap/evaluate/TestDAP_evaluate.py
+++ b/lldb/test/API/tools/lldb-dap/evaluate/TestDAP_evaluate.py
@@ -60,7 +60,10 @@ def run_test_evaluate_expressions(
 
         # Expressions at breakpoint 1, which is in main
         self.assertEvaluate("var1", "20")
+        # Empty expression should equate to the previous expression.
+        self.assertEvaluate("", "20")
         self.assertEvaluate("var2", "21")
+        self.assertEvaluate("", "21")
         self.assertEvaluate("static_int", "42")
         self.assertEvaluate("non_static_int", "43")
         self.assertEvaluate("struct1.foo", "15")
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index c5c4b09f15622b..a6a701dc2219fa 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -1363,6 +1363,14 @@ void request_evaluate(const llvm::json::Object &request) {
   lldb::SBFrame frame = g_dap.GetLLDBFrame(*arguments);
   std::string expression = GetString(arguments, "expression").str();
   llvm::StringRef context = GetString(arguments, "context");
+  static std::string last_nonempty_expression;
+
+  // Remember the last non-empty expression from the user, and use that if
+  // the current expression is empty (i.e. the user hit plain 'return').
+  if (!expression.empty())
+    last_nonempty_expression = expression;
+  else
+    expression = last_nonempty_expression;
 
   if (context == "repl" && g_dap.DetectExpressionContext(frame, expression) ==
                                ExpressionContext::Command) {

>From e35928e08f792163dd4886e797bc6de3d16ea6e6 Mon Sep 17 00:00:00 2001
From: Caroline Tice <cmtice at google.com>
Date: Fri, 6 Sep 2024 10:02:18 -0700
Subject: [PATCH 2/2] [lldb] Add feature to remember last non-empty expression

Make last_nonempty_spression part of DAP struct rather than a
static variable.
---
 lldb/tools/lldb-dap/DAP.h        | 1 +
 lldb/tools/lldb-dap/lldb-dap.cpp | 5 ++---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/lldb/tools/lldb-dap/DAP.h b/lldb/tools/lldb-dap/DAP.h
index f4fdec6e895ad1..4220c15d3ae70d 100644
--- a/lldb/tools/lldb-dap/DAP.h
+++ b/lldb/tools/lldb-dap/DAP.h
@@ -205,6 +205,7 @@ struct DAP {
   std::string command_escape_prefix = "`";
   lldb::SBFormat frame_format;
   lldb::SBFormat thread_format;
+  std::string last_nonempty_expression;
 
   DAP();
   ~DAP();
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index a6a701dc2219fa..d3728df9183aa1 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -1363,14 +1363,13 @@ void request_evaluate(const llvm::json::Object &request) {
   lldb::SBFrame frame = g_dap.GetLLDBFrame(*arguments);
   std::string expression = GetString(arguments, "expression").str();
   llvm::StringRef context = GetString(arguments, "context");
-  static std::string last_nonempty_expression;
 
   // Remember the last non-empty expression from the user, and use that if
   // the current expression is empty (i.e. the user hit plain 'return').
   if (!expression.empty())
-    last_nonempty_expression = expression;
+    g_dap.last_nonempty_expression = expression;
   else
-    expression = last_nonempty_expression;
+    expression = g_dap.last_nonempty_expression;
 
   if (context == "repl" && g_dap.DetectExpressionContext(frame, expression) ==
                                ExpressionContext::Command) {