Fix cpplint. (#4157)

* Add comment after #endif.
* Add missing headers.

include/xgboost/base.h

@@ -16,7 +16,7 @@
  */
 #ifndef XGBOOST_STRICT_R_MODE
 #define XGBOOST_STRICT_R_MODE 0
-#endif
+#endif  // XGBOOST_STRICT_R_MODE
 
 /*!
  * \brief Whether always log console message with time.
@@ -26,21 +26,21 @@
  */
 #ifndef XGBOOST_LOG_WITH_TIME
 #define XGBOOST_LOG_WITH_TIME 1
-#endif
+#endif  // XGBOOST_LOG_WITH_TIME
 
 /*!
  * \brief Whether customize the logger outputs.
  */
 #ifndef XGBOOST_CUSTOMIZE_LOGGER
 #define XGBOOST_CUSTOMIZE_LOGGER XGBOOST_STRICT_R_MODE
-#endif
+#endif  // XGBOOST_CUSTOMIZE_LOGGER
 
 /*!
  * \brief Whether to customize global PRNG.
  */
 #ifndef XGBOOST_CUSTOMIZE_GLOBAL_PRNG
 #define XGBOOST_CUSTOMIZE_GLOBAL_PRNG XGBOOST_STRICT_R_MODE
-#endif
+#endif  // XGBOOST_CUSTOMIZE_GLOBAL_PRNG
 
 /*!
  * \brief Check if alignas(*) keyword is supported. (g++ 4.8 or higher)
@@ -49,7 +49,7 @@
 #define XGBOOST_ALIGNAS(X) alignas(X)
 #else
 #define XGBOOST_ALIGNAS(X)
-#endif
+#endif  // defined(__GNUC__) && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 8) || __GNUC__ > 4)
 
 #if defined(__GNUC__) && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 8) || __GNUC__ > 4) && \
     !defined(__CUDACC__)
@@ -64,7 +64,7 @@
 #else
 #define XGBOOST_PARALLEL_SORT(X, Y, Z) std::sort((X), (Y), (Z))
 #define XGBOOST_PARALLEL_STABLE_SORT(X, Y, Z) std::stable_sort((X), (Y), (Z))
-#endif
+#endif  // GLIBC VERSION
 
 /*!
  * \brief Tag function as usable by device
@@ -73,7 +73,7 @@
 #define XGBOOST_DEVICE __host__ __device__
 #else
 #define XGBOOST_DEVICE
-#endif
+#endif  // defined (__CUDA__) || defined(__NVCC__)
 
 /*! \brief namespace of xgboost*/
 namespace xgboost {
@@ -215,8 +215,8 @@ using bst_omp_uint = dmlc::omp_uint;  // NOLINT
 #if __GNUC__ == 4 && __GNUC_MINOR__ < 8
 #define override
 #define final
-#endif
-#endif
+#endif  // __GNUC__ == 4 && __GNUC_MINOR__ < 8
+#endif  // DMLC_USE_CXX11 && defined(__GNUC__) && !defined(__clang_version__)
 }  // namespace xgboost
 
 /* Always keep this #include at the bottom of xgboost/base.h */

include/xgboost/build_config.h

@@ -13,6 +13,6 @@
 #elif defined(__GNUC__)
 // Enable __builtin_prefetch for GCC
 #define XGBOOST_BUILTIN_PREFETCH_PRESENT
-#endif
+#endif  // GUARDS
 
 #endif  // XGBOOST_BUILD_CONFIG_H_

include/xgboost/c_api.h

@@ -10,11 +10,12 @@
 #ifdef __cplusplus
 #define XGB_EXTERN_C extern "C"
 #include <cstdio>
+#include <cstdint>
 #else
 #define XGB_EXTERN_C
 #include <stdio.h>
 #include <stdint.h>
-#endif
+#endif  // __cplusplus
 
 // XGBoost C API will include APIs in Rabit C API
 #include <rabit/c_api.h>
@@ -23,7 +24,7 @@
 #define XGB_DLL XGB_EXTERN_C __declspec(dllexport)
 #else
 #define XGB_DLL XGB_EXTERN_C
-#endif
+#endif  // defined(_MSC_VER) || defined(_WIN32)
 
 // manually define unsigned long
 typedef uint64_t bst_ulong;  // NOLINT(*)
@@ -49,7 +50,7 @@ typedef struct {  // NOLINT(*)
   long* offset; // NOLINT(*)
 #else
   int64_t* offset;  // NOLINT(*)
-#endif
+#endif  // __APPLE__
   /*! \brief labels of each instance */
   float* label;
   /*! \brief weight of each instance, can be NULL */
@@ -562,7 +563,7 @@ XGB_DLL int XGBoosterGetAttr(BoosterHandle handle,
  *
  * \param handle handle
  * \param key The key of the attribute.
- * \param value The value to be saved. 
+ * \param value The value to be saved.
  *              If nullptr, the attribute would be deleted.
  * \return 0 when success, -1 when failure happens
  */

include/xgboost/learner.h

@@ -11,6 +11,7 @@
 #include <rabit/rabit.h>
 #include <utility>
 #include <map>
+#include <memory>
 #include <string>
 #include <vector>
 #include "./base.h"

include/xgboost/logging.h

@@ -25,7 +25,7 @@ class BaseLogger {
   BaseLogger() {
 #if XGBOOST_LOG_WITH_TIME
     log_stream_ << "[" << dmlc::DateLogger().HumanDate() << "] ";
-#endif
+#endif  // XGBOOST_LOG_WITH_TIME
   }
   std::ostream& stream() { return log_stream_; }  // NOLINT
 
@@ -116,14 +116,14 @@ class LogCallbackRegistry {
     return nullptr;
   }
 };
-#endif
+#endif  // !defined(XGBOOST_STRICT_R_MODE) || XGBOOST_STRICT_R_MODE == 0
 
 using LogCallbackRegistryStore = dmlc::ThreadLocalStore<LogCallbackRegistry>;
 
 // Redefines LOG_WARNING for controling verbosity
 #if defined(LOG_WARNING)
 #undef  LOG_WARNING
-#endif
+#endif  // defined(LOG_WARNING)
 #define LOG_WARNING                                                            \
   if (::xgboost::ConsoleLogger::ShouldLog(                                     \
           ::xgboost::ConsoleLogger::LV::kWarning))                             \
@@ -133,7 +133,7 @@ using LogCallbackRegistryStore = dmlc::ThreadLocalStore<LogCallbackRegistry>;
 // Redefines LOG_INFO for controling verbosity
 #if defined(LOG_INFO)
 #undef  LOG_INFO
-#endif
+#endif  // defined(LOG_INFO)
 #define LOG_INFO                                                               \
   if (::xgboost::ConsoleLogger::ShouldLog(                                     \
           ::xgboost::ConsoleLogger::LV::kInfo))                                \
@@ -142,7 +142,7 @@ using LogCallbackRegistryStore = dmlc::ThreadLocalStore<LogCallbackRegistry>;
 
 #if defined(LOG_DEBUG)
 #undef LOG_DEBUG
-#endif
+#endif  // defined(LOG_DEBUG)
 #define LOG_DEBUG                                                              \
   if (::xgboost::ConsoleLogger::ShouldLog(                                     \
           ::xgboost::ConsoleLogger::LV::kDebug))                               \
@@ -152,7 +152,7 @@ using LogCallbackRegistryStore = dmlc::ThreadLocalStore<LogCallbackRegistry>;
 // redefines the logging macro if not existed
 #ifndef LOG
 #define LOG(severity) LOG_##severity.stream()
-#endif
+#endif  // LOG
 
 // Enable LOG(CONSOLE) for print messages to console.
 #define LOG_CONSOLE ::xgboost::ConsoleLogger(           \

include/xgboost/predictor.h

@@ -7,11 +7,14 @@
 #pragma once
 #include <xgboost/base.h>
 #include <xgboost/data.h>
+
 #include <functional>
 #include <memory>
 #include <string>
+#include <unordered_map>
 #include <utility>
 #include <vector>
+
 #include "../../src/gbm/gbtree_model.h"
 #include "../../src/common/host_device_vector.h"