Fix -Wsign-compare warnings in parser, scanner, regexp, runtime.

src/libsampler/sampler.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/libsampler/sampler.h"
 
 #if V8_OS_POSIX && !V8_OS_CYGWIN
 
 #define USE_SIGNALS
 
@@ skipping 263 matching lines @@
 #if defined(USE_SIGNALS)
   void DoSample(const v8::RegisterState& state) {
     AtomicGuard atomic_guard(&SamplerManager::samplers_access_counter_, false);
     if (!atomic_guard.is_success()) return;
     pthread_t thread_id = pthread_self();
     base::HashMap::Entry* entry =
         sampler_map_.Lookup(ThreadKey(thread_id), ThreadHash(thread_id));
     if (!entry) return;
     SamplerList& samplers = *static_cast<SamplerList*>(entry->value);
 
-    for (int i = 0; i < samplers.size(); ++i) {
+    for (size_t i = 0; i < samplers.size(); ++i) {
       Sampler* sampler = samplers[i];
       Isolate* isolate = sampler->isolate();
       // We require a fully initialized and entered isolate.
       if (isolate == nullptr || !isolate->IsInUse()) continue;
       if (v8::Locker::IsActive() && !Locker::IsLocked(isolate)) continue;
       sampler->SampleStack(state);
     }
   }
 #endif
 
@@ skipping 359 matching lines @@
 #endif
     SampleStack(state);
   }
   ResumeThread(profiled_thread);
 }
 
 #endif  // USE_SIGNALS
 
 }  // namespace sampler
 }  // namespace v8