Warn if a global function has no previous declaration

If a global function has no previous declaration, either the declaration
is missing in the corresponding header file or the function should be
declared static. Static functions are local to the translation unit,
which allows the compiler to apply some optimizations earlier (when
compiling the translation unit rather than during link-time
optimization).

The commit enables the warning for gcc, clang, and mingw. It also fixes
the reported warnings by declaring the functions static or by adding a
header file (benchmark.h).

closes https://github.com/official-stockfish/Stockfish/pull/4325

No functional change

diff --git a/src/Makefile b/src/Makefile
index d4f089ee4236d8ec7b64d84d771d8e7491eb194c..30c1be5ee527f85d3413ee525d646e5e90f759a6 100644 (file)
--- a/src/Makefile
+++ b/src/Makefile
@@ -366,7 +366,7 @@ endif
 ifeq ($(COMP),gcc)
        comp=gcc
        CXX=g++
-       CXXFLAGS += -pedantic -Wextra -Wshadow
+       CXXFLAGS += -pedantic -Wextra -Wshadow -Wmissing-declarations
 
        ifeq ($(arch),$(filter $(arch),armv7 armv8 riscv64))
                ifeq ($(OS),Android)
@@ -410,7 +410,7 @@ ifeq ($(COMP),mingw)
                        CXX=i686-w64-mingw32-c++-posix
                endif
        endif
-       CXXFLAGS += -pedantic -Wextra -Wshadow
+       CXXFLAGS += -pedantic -Wextra -Wshadow -Wmissing-declarations
 endif
 
 ifeq ($(COMP),icc)
@@ -426,7 +426,7 @@ ifeq ($(COMP),clang)
                CXX=x86_64-w64-mingw32-clang++
        endif
 
-       CXXFLAGS += -pedantic -Wextra -Wshadow
+       CXXFLAGS += -pedantic -Wextra -Wshadow -Wmissing-prototypes
 
        ifeq ($(filter $(KERNEL),Darwin OpenBSD FreeBSD),)
        ifeq ($(target_windows),)

diff --git a/src/benchmark.cpp b/src/benchmark.cpp
index 2abb9c8fbb5f868c78597c3dc4b93879821dffe3..a1ad055057b70a646e7f01bcf76bfffffc83b581 100644 (file)
--- a/src/benchmark.cpp
+++ b/src/benchmark.cpp
@@ -16,6 +16,8 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include "benchmark.h"
+
 #include <fstream>
 #include <iostream>
 #include <istream>

diff --git a/src/benchmark.h b/src/benchmark.h
new file mode 100644 (file)
index 0000000..64acf83
--- /dev/null
+++ b/src/benchmark.h
@@ -0,0 +1,34 @@
+/*
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
+
+  Stockfish is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  Stockfish is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef BENCHMARK_H_INCLUDED
+#define BENCHMARK_H_INCLUDED
+
+#include <iosfwd>
+#include <string>
+#include <vector>
+
+namespace Stockfish {
+
+class Position;
+
+std::vector<std::string> setup_bench(const Position&, std::istream&);
+
+} // namespace Stockfish
+
+#endif // #ifndef BENCHMARK_H_INCLUDED

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index d5cda3d80e86ef9a9f779abc1aa6b39c2bb7108e..3aae9f1c6ec3d337d5a9c953e5e528cf3a341439 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -159,24 +159,24 @@ namespace Trace {
 
   Score scores[TERM_NB][COLOR_NB];
 
-  double to_cp(Value v) { return double(v) / UCI::NormalizeToPawnValue; }
+  static double to_cp(Value v) { return double(v) / UCI::NormalizeToPawnValue; }
 
-  void add(int idx, Color c, Score s) {
+  static void add(int idx, Color c, Score s) {
     scores[idx][c] = s;
   }
 
-  void add(int idx, Score w, Score b = SCORE_ZERO) {
+  static void add(int idx, Score w, Score b = SCORE_ZERO) {
     scores[idx][WHITE] = w;
     scores[idx][BLACK] = b;
   }
 
-  std::ostream& operator<<(std::ostream& os, Score s) {
+  static std::ostream& operator<<(std::ostream& os, Score s) {
     os << std::setw(5) << to_cp(mg_value(s)) << " "
        << std::setw(5) << to_cp(eg_value(s));
     return os;
   }
 
-  std::ostream& operator<<(std::ostream& os, Term t) {
+  static std::ostream& operator<<(std::ostream& os, Term t) {
 
     if (t == MATERIAL || t == IMBALANCE || t == WINNABLE || t == TOTAL)
         os << " ----  ----"    << " | " << " ----  ----";

diff --git a/src/misc.cpp b/src/misc.cpp
index 5bb8da697a06bd90807388ee574339d70bab6d12..1cb515c3e41f20e6d081061e806b77f7436b2df6 100644 (file)
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -517,7 +517,7 @@ void bindThisThread(size_t) {}
 /// API and returns the best node id for the thread with index idx. Original
 /// code from Texel by Peter Österlund.
 
-int best_node(size_t idx) {
+static int best_node(size_t idx) {
 
   int threads = 0;
   int nodes = 0;

diff --git a/src/nnue/evaluate_nnue.cpp b/src/nnue/evaluate_nnue.cpp
index 8d720ccbcf753889469e544271758b633a46abd7..a06c1978517b34bede52f8fd873ee85913505b43 100644 (file)
--- a/src/nnue/evaluate_nnue.cpp
+++ b/src/nnue/evaluate_nnue.cpp
@@ -83,7 +83,7 @@ namespace Stockfish::Eval::NNUE {
   }  // namespace Detail
 
   // Initialize the evaluation function parameters
-  void initialize() {
+  static void initialize() {
 
     Detail::initialize(featureTransformer);
     for (std::size_t i = 0; i < LayerStacks; ++i)
@@ -91,7 +91,7 @@ namespace Stockfish::Eval::NNUE {
   }
 
   // Read network header
-  bool read_header(std::istream& stream, std::uint32_t* hashValue, std::string* desc)
+  static bool read_header(std::istream& stream, std::uint32_t* hashValue, std::string* desc)
   {
     std::uint32_t version, size;
 
@@ -105,7 +105,7 @@ namespace Stockfish::Eval::NNUE {
   }
 
   // Write network header
-  bool write_header(std::ostream& stream, std::uint32_t hashValue, const std::string& desc)
+  static bool write_header(std::ostream& stream, std::uint32_t hashValue, const std::string& desc)
   {
     write_little_endian<std::uint32_t>(stream, Version);
     write_little_endian<std::uint32_t>(stream, hashValue);
@@ -115,7 +115,7 @@ namespace Stockfish::Eval::NNUE {
   }
 
   // Read network parameters
-  bool read_parameters(std::istream& stream) {
+  static bool read_parameters(std::istream& stream) {
 
     std::uint32_t hashValue;
     if (!read_header(stream, &hashValue, &netDescription)) return false;
@@ -127,7 +127,7 @@ namespace Stockfish::Eval::NNUE {
   }
 
   // Write network parameters
-  bool write_parameters(std::ostream& stream) {
+  static bool write_parameters(std::ostream& stream) {
 
     if (!write_header(stream, HashValue, netDescription)) return false;
     if (!Detail::write_parameters(stream, *featureTransformer)) return false;

diff --git a/src/uci.cpp b/src/uci.cpp
index c49b9b78a4985123ac125cd63142b5b456e5bb1e..eb158e723e4e37d2d6b9c71e15d2002099165dd2 100644 (file)
--- a/src/uci.cpp
+++ b/src/uci.cpp
@@ -22,6 +22,7 @@
 #include <sstream>
 #include <string>
 
+#include "benchmark.h"
 #include "evaluate.h"
 #include "movegen.h"
 #include "position.h"
@@ -36,8 +37,6 @@ using namespace std;
 
 namespace Stockfish {
 
-vector<string> setup_bench(const Position&, istream&);
-
 namespace {
 
   // FEN string for the initial position in standard chess

diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index 78711c1816c06993166f509583b5dae2319edd03..b4ce70b4ed2ef2fdb28b77da3c5532f2bf8f0bc5 100644 (file)
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -38,13 +38,13 @@ UCI::OptionsMap Options; // Global object
 namespace UCI {
 
 /// 'On change' actions, triggered by an option's value change
-void on_clear_hash(const Option&) { Search::clear(); }
-void on_hash_size(const Option& o) { TT.resize(size_t(o)); }
-void on_logger(const Option& o) { start_logger(o); }
-void on_threads(const Option& o) { Threads.set(size_t(o)); }
-void on_tb_path(const Option& o) { Tablebases::init(o); }
-void on_use_NNUE(const Option& ) { Eval::NNUE::init(); }
-void on_eval_file(const Option& ) { Eval::NNUE::init(); }
+static void on_clear_hash(const Option&) { Search::clear(); }
+static void on_hash_size(const Option& o) { TT.resize(size_t(o)); }
+static void on_logger(const Option& o) { start_logger(o); }
+static void on_threads(const Option& o) { Threads.set(size_t(o)); }
+static void on_tb_path(const Option& o) { Tablebases::init(o); }
+static void on_use_NNUE(const Option&) { Eval::NNUE::init(); }
+static void on_eval_file(const Option&) { Eval::NNUE::init(); }
 
 /// Our case insensitive less() function as required by UCI protocol
 bool CaseInsensitiveLess::operator() (const string& s1, const string& s2) const {