[lldb][progress] Correctly check total for deterministic progress (llvm#79912)

The `total` parameter for the constructor for Progress was changed to a
std::optional in llvm#77547. It was originally set to 1 to indicate non-determinisitic progress, but this commit changes this. First, `UINT64_MAX` will again be used for non-deterministic progress, and `Progress` now has a static variable set to this value so that we can use this instead of a magic number.

The member variable `m_total` could be changed to a std::optional as
well, but this means that the `ProgressEventData::GetTotal()` (which is
used for the public API) would
either need to return a std::optional value or it would return some
specific integer to represent non-deterministic progress if `m_total` is
std::nullopt.

(cherry picked from commit 733b86d)

Author: chelcassanova

lldb/include/lldb/Core/DebuggerEvents.h

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Core/ModuleSpec.h"
+#include "lldb/Core/Progress.h"
 #include "lldb/Utility/Event.h"
 #include "lldb/Utility/StructuredData.h"
 
@@ -39,7 +40,7 @@ class ProgressEventData : public EventData {
   GetAsStructuredData(const Event *event_ptr);
 
   uint64_t GetID() const { return m_id; }
-  bool IsFinite() const { return m_total != UINT64_MAX; }
+  bool IsFinite() const { return m_total != Progress::kNonDeterministicTotal; }
   uint64_t GetCompleted() const { return m_completed; }
   uint64_t GetTotal() const { return m_total; }
   std::string GetMessage() const {

lldb/include/lldb/Core/Progress.h

@@ -93,6 +93,9 @@ class Progress {
   void Increment(uint64_t amount = 1,
                  std::optional<std::string> updated_detail = {});
 
+  /// Used to indicate a non-deterministic progress report
+  static constexpr uint64_t kNonDeterministicTotal = UINT64_MAX;
+
 private:
   void ReportProgress();
   static std::atomic<uint64_t> g_id;

lldb/source/Core/DebuggerEvents.cpp

@@ -9,6 +9,7 @@
 #include "lldb/Core/DebuggerEvents.h"
 #include "lldb/Core/Debugger.h"
 #include "lldb/Core/Module.h"
+#include "lldb/Core/Progress.h"
 #include "llvm/Support/WithColor.h"
 
 using namespace lldb_private;
@@ -41,7 +42,7 @@ void ProgressEventData::Dump(Stream *s) const {
     s->PutCString(", type = update");
   // If m_total is UINT64_MAX, there is no progress to report, just "start"
   // and "end". If it isn't we will show the completed and total amounts.
-  if (m_total != UINT64_MAX)
+  if (m_total != Progress::kNonDeterministicTotal)
     s->Printf(", progress = %" PRIu64 " of %" PRIu64, m_completed, m_total);
 }
 

lldb/source/Core/Progress.cpp

@@ -22,8 +22,7 @@ Progress::Progress(std::string title, std::string details,
                    std::optional<uint64_t> total,
                    lldb_private::Debugger *debugger)
     : m_title(title), m_details(details), m_id(++g_id), m_completed(0),
-      m_total(1) {
-  assert(total == std::nullopt || total > 0);
+      m_total(Progress::kNonDeterministicTotal) {
   if (total)
     m_total = *total;