Fix time span in profiler

runtime/vm/profiler_service.cc

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/profiler_service.h"
 
 #include "vm/growable_array.h"
 #include "vm/native_symbol.h"
 #include "vm/object.h"
 #include "vm/os.h"
@@ skipping 1053 matching lines @@
     profile_->sample_count_ = samples_->length();
   }
 
   void UpdateMinMaxTimes(int64_t timestamp) {
     profile_->min_time_ =
         timestamp < profile_->min_time_ ? timestamp : profile_->min_time_;
     profile_->max_time_ =
         timestamp > profile_->max_time_ ? timestamp : profile_->max_time_;
   }
 
+  void SanitizeMinMaxTimes() {
+    if ((profile_->min_time_ == kMaxInt64) && (profile_->max_time_ == 0)) {
+      profile_->min_time_ = 0;
+      profile_->max_time_ = 0;
+    }
+  }
+
   void BuildCodeTable() {
     ScopeTimer sw("ProfileBuilder::BuildCodeTable", FLAG_trace_profiler);
     for (intptr_t sample_index = 0;
          sample_index < samples_->length();
          sample_index++) {
       ProcessedSample* sample = samples_->At(sample_index);
       const int64_t timestamp = sample->timestamp();
 
       // This is our first pass over the sample buffer, use this as an
       // opportunity to determine the min and max time ranges of this profile.
@@ skipping 14 matching lines @@
       for (intptr_t frame_index = 0;
            frame_index < sample->length();
            frame_index++) {
         const uword pc = sample->At(frame_index);
         ASSERT(pc != 0);
         ProfileCode* code = RegisterProfileCode(pc, timestamp);
         ASSERT(code != NULL);
         code->Tick(pc, IsExecutingFrame(sample, frame_index), sample_index);
       }
     }
+    SanitizeMinMaxTimes();
   }
 
   void FinalizeCodeIndexes() {
     ScopeTimer sw("ProfileBuilder::FinalizeCodeIndexes", FLAG_trace_profiler);
     ProfileCodeTable* live_table = profile_->live_code_;
     ProfileCodeTable* dead_table = profile_->dead_code_;
     ProfileCodeTable* tag_table = profile_->tag_code_;
     const intptr_t dead_code_index_offset = live_table->length();
     const intptr_t tag_code_index_offset =
         dead_table->length() + dead_code_index_offset;
@@ skipping 1161 matching lines @@
   ASSERT(sample_buffer != NULL);
 
   ClearProfileVisitor clear_profile(isolate);
   sample_buffer->VisitSamples(&clear_profile);
 
   // Enable profile interrupts.
   Profiler::BeginExecution(isolate);
 }
 
 }  // namespace dart