Fix a bug due to lazy initailization in debugging model.

PiperOrigin-RevId: 598476395

third_party/xla/xla/lazy.h

@@ -28,6 +28,8 @@ class Lazy {
   explicit Lazy(absl::AnyInvocable<T() &&> func)
       : maybe_value_(std::move(func)) {}
 
+  bool has_value() const { return std::holds_alternative<T>(maybe_value_); }
+
   const T& get() const {
     if (!std::holds_alternative<T>(maybe_value_)) {
       maybe_value_ =

third_party/xla/xla/service/hlo_dataflow_analysis.cc

@@ -1648,8 +1648,8 @@ void HloDataflowAnalysis::OptimizePhiValues() {
             HloValue::Id phi_id = values[0]->id();
             HloValue::Id new_id = phi_graph_.FindOptimizedValue(phi_id);
             if (new_id != phi_id) {
-              VLOG(1) << "Replacing " << values[0]->ToString() << " with "
-                      << GetValue(new_id).ToString();
+              VLOG(1) << "Replacing " << values[0]->ToShortString() << " with "
+                      << GetValue(new_id).ToShortString();
               value_set->Clear();
               const HloValue& new_value = GetValue(new_id);
               value_set->AddValue(&new_value);

third_party/xla/xla/service/hlo_value.cc

@@ -16,27 +16,27 @@ limitations under the License.
 #include "xla/service/hlo_value.h"
 
 #include <algorithm>
-#include <memory>
+#include <cstdint>
+#include <ostream>
+#include <string>
 #include <utility>
 #include <vector>
 
 #include "absl/algorithm/container.h"
 #include "absl/container/flat_hash_set.h"
-#include "absl/container/inlined_vector.h"
 #include "absl/log/check.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_format.h"
 #include "absl/strings/str_join.h"
+#include "absl/types/span.h"
 #include "xla/hlo/ir/hlo_computation.h"
 #include "xla/hlo/ir/hlo_instruction.h"
 #include "xla/hlo/ir/hlo_module.h"
 #include "xla/hlo/ir/hlo_opcode.h"
-#include "xla/map_util.h"
+#include "xla/service/buffer_value.h"
+#include "xla/shape.h"
 #include "xla/shape_util.h"
-#include "xla/status.h"
-#include "xla/types.h"
 #include "xla/util.h"
-#include "tsl/platform/errors.h"
 #include "tsl/platform/logging.h"
 
 namespace xla {
@@ -95,9 +95,13 @@ std::string HloValue::ToString(int indent) const {
   for (const HloPosition& position : positions()) {
     StrAppend(&out, indentation, "  ", position.ToString(), "\n");
   }
-  StrAppend(&out, indentation, " uses:\n");
-  for (const HloUse& use : GetUses()) {
-    StrAppend(&out, indentation, "  ", use.ToString(), "\n");
+  if (uses_.has_value()) {
+    StrAppend(&out, indentation, " uses:\n");
+    for (const HloUse& use : GetUses()) {
+      StrAppend(&out, indentation, "  ", use.ToString(), "\n");
+    }
+  } else {
+    StrAppend(&out, indentation, " uses are not initialized yet.\n");
   }
   StrAppend(&out, indentation, " from instruction:", instruction()->ToString(),
             "\n");

third_party/xla/xla/service/hlo_value.h

@@ -18,20 +18,22 @@ limitations under the License.
 
 #include <stddef.h>
 
+#include <cstdint>
+#include <ostream>
 #include <string>
 #include <tuple>
 #include <utility>
 #include <vector>
 
-#include "absl/algorithm/container.h"
 #include "absl/container/flat_hash_set.h"
+#include "absl/container/inlined_vector.h"
 #include "absl/types/span.h"
 #include "xla/hlo/ir/hlo_instruction.h"
 #include "xla/lazy.h"
 #include "xla/service/buffer_value.h"
+#include "xla/shape.h"
 #include "xla/shape_tree.h"
 #include "xla/shape_util.h"
-#include "xla/types.h"
 #include "xla/xla_data.pb.h"
 #include "tsl/platform/logging.h"
 
@@ -164,6 +166,8 @@ class HloValue : public BufferValue {
 
   // Return a single-line string representation of the value.
   std::string ToShortString() const;
+  // The returned string doesn't include `uses` if the ToString is called before
+  // `GetUses` is called.
   std::string ToString(int indent) const;
   std::string ToString() const override { return ToString(0); }
 
@@ -250,7 +254,7 @@ class HloValueSet {
   std::vector<const HloValue*> values_;
 };
 
-std::ostream& operator<<(std::ostream& out, const HloValueSet& hlo_value);
+std::ostream& operator<<(std::ostream& out, const HloValueSet& value_set);
 
 // A class collecting the HloValues which might be contained in the output of
 // an HLO instruction. For array-shaped instructions, an InstructionValueSet