[lldb] Unify target checking in CommandObject

Summary:
We currently have several CommandObjects that manually reimplement the checking for a selected target
or a target in the execution context (which is the selected target when they are invoked). This patch removes
all these checks and replaces them by setting the eCommandRequiresTarget flag that Pavel suggested. With
this flag we are doing the same check but without having to duplicate this code in all these CommandObjects.

I also added a `GetSelectedTarget()` variant of the `GetSelectedOrDummyTarget()` function to the
CommandObject that checks that the flag is set and then returns a reference to the target. I didn't rewrite
all the `target` variables from `Target *` to `Target &` in this patch as last time this change caused a lot of merge
conflicts in Swift and I would prefer having that in a separate NFC commit.

Reviewers: labath, clayborg

Reviewed By: labath, clayborg

Subscribers: clayborg, JDevlieghere, jingham, amccarth, abidh, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D66863

llvm-svn: 370571

1 files changed, 13 insertions, 22 deletions

diff --git a/lldb/source/Commands/CommandObjectWatchpoint.cpp b/lldb/source/Commands/CommandObjectWatchpoint.cpp
index 5ddec476930..67fd27887be 100644
--- a/lldb/source/Commands/CommandObjectWatchpoint.cpp
+++ b/lldb/source/Commands/CommandObjectWatchpoint.cpp
@@ -40,11 +40,6 @@ static void AddWatchpointDescription(Stream *s, Watchpoint *wp,
 
 static bool CheckTargetForWatchpointOperations(Target *target,
                                                CommandReturnObject &result) {
-  if (target == nullptr) {
-    result.AppendError("Invalid target.  No existing target or watchpoints.");
-    result.SetStatus(eReturnStatusFailed);
-    return false;
-  }
   bool process_is_valid =
       target->GetProcessSP() && target->GetProcessSP()->IsAlive();
   if (!process_is_valid) {
@@ -156,7 +151,8 @@ public:
   CommandObjectWatchpointList(CommandInterpreter &interpreter)
       : CommandObjectParsed(
             interpreter, "watchpoint list",
-            "List all watchpoints at configurable levels of detail.", nullptr),
+            "List all watchpoints at configurable levels of detail.", nullptr,
+            eCommandRequiresTarget),
         m_options() {
     CommandArgumentEntry arg;
     CommandObject::AddIDsArgumentData(arg, eArgTypeWatchpointID,
@@ -217,12 +213,7 @@ public:
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
-    Target *target = GetDebugger().GetSelectedTarget().get();
-    if (target == nullptr) {
-      result.AppendError("Invalid target. No current target or watchpoints.");
-      result.SetStatus(eReturnStatusSuccessFinishNoResult);
-      return true;
-    }
+    Target *target = &GetSelectedTarget();
 
     if (target->GetProcessSP() && target->GetProcessSP()->IsAlive()) {
       uint32_t num_supported_hardware_watchpoints;
@@ -292,7 +283,7 @@ public:
       : CommandObjectParsed(interpreter, "enable",
                             "Enable the specified disabled watchpoint(s). If "
                             "no watchpoints are specified, enable all of them.",
-                            nullptr) {
+                            nullptr, eCommandRequiresTarget) {
     CommandArgumentEntry arg;
     CommandObject::AddIDsArgumentData(arg, eArgTypeWatchpointID,
                                       eArgTypeWatchpointIDRange);
@@ -305,7 +296,7 @@ public:
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
-    Target *target = GetDebugger().GetSelectedTarget().get();
+    Target *target = &GetSelectedTarget();
     if (!CheckTargetForWatchpointOperations(target, result))
       return false;
 
@@ -362,7 +353,7 @@ public:
                             "Disable the specified watchpoint(s) without "
                             "removing it/them.  If no watchpoints are "
                             "specified, disable them all.",
-                            nullptr) {
+                            nullptr, eCommandRequiresTarget) {
     CommandArgumentEntry arg;
     CommandObject::AddIDsArgumentData(arg, eArgTypeWatchpointID,
                                       eArgTypeWatchpointIDRange);
@@ -375,7 +366,7 @@ public:
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
-    Target *target = GetDebugger().GetSelectedTarget().get();
+    Target *target = &GetSelectedTarget();
     if (!CheckTargetForWatchpointOperations(target, result))
       return false;
 
@@ -434,7 +425,7 @@ public:
       : CommandObjectParsed(interpreter, "watchpoint delete",
                             "Delete the specified watchpoint(s).  If no "
                             "watchpoints are specified, delete them all.",
-                            nullptr) {
+                            nullptr, eCommandRequiresTarget) {
     CommandArgumentEntry arg;
     CommandObject::AddIDsArgumentData(arg, eArgTypeWatchpointID,
                                       eArgTypeWatchpointIDRange);
@@ -447,7 +438,7 @@ public:
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
-    Target *target = GetDebugger().GetSelectedTarget().get();
+    Target *target = &GetSelectedTarget();
     if (!CheckTargetForWatchpointOperations(target, result))
       return false;
 
@@ -511,7 +502,7 @@ public:
       : CommandObjectParsed(interpreter, "watchpoint ignore",
                             "Set ignore count on the specified watchpoint(s).  "
                             "If no watchpoints are specified, set them all.",
-                            nullptr),
+                            nullptr, eCommandRequiresTarget),
         m_options() {
     CommandArgumentEntry arg;
     CommandObject::AddIDsArgumentData(arg, eArgTypeWatchpointID,
@@ -564,7 +555,7 @@ public:
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
-    Target *target = GetDebugger().GetSelectedTarget().get();
+    Target *target = &GetSelectedTarget();
     if (!CheckTargetForWatchpointOperations(target, result))
       return false;
 
@@ -631,7 +622,7 @@ public:
             "If no watchpoint is specified, act on the last created "
             "watchpoint.  "
             "Passing an empty argument clears the modification.",
-            nullptr),
+            nullptr, eCommandRequiresTarget),
         m_options() {
     CommandArgumentEntry arg;
     CommandObject::AddIDsArgumentData(arg, eArgTypeWatchpointID,
@@ -685,7 +676,7 @@ public:
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
-    Target *target = GetDebugger().GetSelectedTarget().get();
+    Target *target = &GetSelectedTarget();
     if (!CheckTargetForWatchpointOperations(target, result))
       return false;