[lldb/Target] Add ability to set a label to targets

This patch add the ability for the user to set a label for a target.

This can be very useful when debugging targets with the same executables
in the same session.

Labels can be set either at the target creation in the command
interpreter or at any time using the SBAPI.

Target labels show up in the `target list` output, following the target
index, and they also allow the user to switch targets using them.

rdar://105016191

Differential Revision: https://reviews.llvm.org/D151859

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>

1 files changed, 46 insertions, 10 deletions

diff --git a/lldb/source/Commands/CommandObjectTarget.cpp b/lldb/source/Commands/CommandObjectTarget.cpp
index e3bb7fc..0088211 100644
--- a/lldb/source/Commands/CommandObjectTarget.cpp
+++ b/lldb/source/Commands/CommandObjectTarget.cpp
@@ -82,8 +82,14 @@ static void DumpTargetInfo(uint32_t target_idx, Target *target,
   if (!exe_valid)
     ::strcpy(exe_path, "<none>");
 
-  strm.Printf("%starget #%u: %s", prefix_cstr ? prefix_cstr : "", target_idx,
-              exe_path);
+  std::string formatted_label = "";
+  const std::string &label = target->GetLabel();
+  if (!label.empty()) {
+    formatted_label = " (" + label + ")";
+  }
+
+  strm.Printf("%starget #%u%s: %s", prefix_cstr ? prefix_cstr : "", target_idx,
+              formatted_label.data(), exe_path);
 
   uint32_t properties = 0;
   if (target_arch.IsValid()) {
@@ -209,6 +215,8 @@ public:
         m_platform_options(true), // Include the --platform option.
         m_core_file(LLDB_OPT_SET_1, false, "core", 'c', 0, eArgTypeFilename,
                     "Fullpath to a core file to use for this target."),
+        m_label(LLDB_OPT_SET_1, false, "label", 'l', 0, eArgTypeName,
+                "Optional name for this target.", nullptr),
         m_symbol_file(LLDB_OPT_SET_1, false, "symfile", 's', 0,
                       eArgTypeFilename,
                       "Fullpath to a stand alone debug "
@@ -234,6 +242,7 @@ public:
     m_option_group.Append(&m_arch_option, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
     m_option_group.Append(&m_platform_options, LLDB_OPT_SET_ALL, 1);
     m_option_group.Append(&m_core_file, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
+    m_option_group.Append(&m_label, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
     m_option_group.Append(&m_symbol_file, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
     m_option_group.Append(&m_remote_file, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
     m_option_group.Append(&m_add_dependents, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
@@ -303,6 +312,14 @@ protected:
         return false;
       }
 
+      const llvm::StringRef label =
+          m_label.GetOptionValue().GetCurrentValueAsRef();
+      if (!label.empty()) {
+        if (auto E = target_sp->SetLabel(label))
+          result.SetError(std::move(E));
+        return false;
+      }
+
       auto on_error = llvm::make_scope_exit(
           [&target_list = debugger.GetTargetList(), &target_sp]() {
             target_list.DeleteTarget(target_sp);
@@ -455,6 +472,7 @@ private:
   OptionGroupArchitecture m_arch_option;
   OptionGroupPlatform m_platform_options;
   OptionGroupFile m_core_file;
+  OptionGroupString m_label;
   OptionGroupFile m_symbol_file;
   OptionGroupFile m_remote_file;
   OptionGroupDependents m_add_dependents;
@@ -503,11 +521,11 @@ public:
 protected:
   bool DoExecute(Args &args, CommandReturnObject &result) override {
     if (args.GetArgumentCount() == 1) {
-      const char *target_idx_arg = args.GetArgumentAtIndex(0);
-      uint32_t target_idx;
-      if (llvm::to_integer(target_idx_arg, target_idx)) {
-        TargetList &target_list = GetDebugger().GetTargetList();
-        const uint32_t num_targets = target_list.GetNumTargets();
+      const char *target_identifier = args.GetArgumentAtIndex(0);
+      uint32_t target_idx = LLDB_INVALID_INDEX32;
+      TargetList &target_list = GetDebugger().GetTargetList();
+      const uint32_t num_targets = target_list.GetNumTargets();
+      if (llvm::to_integer(target_identifier, target_idx)) {
         if (target_idx < num_targets) {
           target_list.SetSelectedTarget(target_idx);
           Stream &strm = result.GetOutputStream();
@@ -526,8 +544,26 @@ protected:
           }
         }
       } else {
-        result.AppendErrorWithFormat("invalid index string value '%s'\n",
-                                     target_idx_arg);
+        for (size_t i = 0; i < num_targets; i++) {
+          if (TargetSP target_sp = target_list.GetTargetAtIndex(i)) {
+            const std::string &label = target_sp->GetLabel();
+            if (!label.empty() && label == target_identifier) {
+              target_idx = i;
+              break;
+            }
+          }
+        }
+
+        if (target_idx != LLDB_INVALID_INDEX32) {
+          target_list.SetSelectedTarget(target_idx);
+          Stream &strm = result.GetOutputStream();
+          bool show_stopped_process_status = false;
+          DumpTargetList(target_list, show_stopped_process_status, strm);
+          result.SetStatus(eReturnStatusSuccessFinishResult);
+        } else {
+          result.AppendErrorWithFormat("invalid index string value '%s'\n",
+                                       target_identifier);
+        }
       }
     } else {
       result.AppendError(
@@ -576,7 +612,7 @@ protected:
     TargetSP target_sp;
 
     if (m_all_option.GetOptionValue()) {
-      for (int i = 0; i < target_list.GetNumTargets(); ++i)
+      for (size_t i = 0; i < target_list.GetNumTargets(); ++i)
         delete_target_list.push_back(target_list.GetTargetAtIndex(i));
     } else if (argc > 0) {
       const uint32_t num_targets = target_list.GetNumTargets();