Initial implementation of scope guard logging for including in crash logs.

This adds a mechanism to create scope guards with an associated std::function
which is called to output diagnostic info in the event of a crash.
Add a macro to make it easy to efficiently capture variables on the stack
and output a formatted message.
Requires C++11, #ifdefed out for legacy compilers.

source.list

@@ -1194,3 +1194,6 @@ thread/thread.h
 #else
 	thread/thread_none.cpp
 #end
+
+scope_info.cpp
+scope_info.h

src/crashlog.cpp

@@ -28,6 +28,8 @@
 #include "network/network.h"
 #include "language.h"
 #include "fontcache.h"
+#include "scope_info.h"
+#include "thread/thread.h"
 
 #include "ai/ai_info.hpp"
 #include "game/game.hpp"
@@ -327,6 +329,13 @@ char *CrashLog::FillCrashLog(char *buffer, const char *last) const
 	buffer += seprintf(buffer, last, "In game date: %i-%02i-%02i (%i)\n\n", ymd.year, ymd.month + 1, ymd.day, _date_fract);
 
 	buffer = this->LogError(buffer, last, CrashLog::message);
+
+#ifdef USE_SCOPE_INFO
+	if (IsMainThread()) {
+		buffer += WriteScopeLog(buffer, last);
+	}
+#endif
+
 	buffer = this->LogOpenTTDVersion(buffer, last);
 	buffer = this->LogRegisters(buffer, last);
 	buffer = this->LogStacktrace(buffer, last);

src/scope_info.cpp

@@ -0,0 +1,72 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD 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, version 2.
+ * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file scope_info.cpp Scope info debug functions. */
+
+#include "stdafx.h"
+#include "scope_info.h"
+#include "string_func.h"
+#include "strings_func.h"
+#include "company_base.h"
+#include "vehicle_base.h"
+#include "table/strings.h"
+
+#include "safeguards.h"
+
+#ifdef USE_SCOPE_INFO
+
+std::vector<std::function<int(char *, const char *)>> _scope_stack;
+
+int WriteScopeLog(char *buf, const char *last)
+{
+	char *b = buf;
+	if (!_scope_stack.empty()) {
+		b += seprintf(b, last, "Within context:");
+		int depth = 0;
+		for (auto it = _scope_stack.rbegin(); it != _scope_stack.rend(); ++it, depth++) {
+			b += seprintf(b, last, "\n    %2d: ", depth);
+			b += (*it)(b, last);
+		}
+		b += seprintf(b, last, "\n\n");
+	}
+	return b - buf;
+}
+
+// helper functions
+char *DumpCompanyInfo(int company_id)
+{
+	char buf[256];
+	char *b = buf + seprintf(buf, lastof(buf), "%d (", company_id);
+	SetDParam(0, company_id);
+	b = GetString(b, STR_COMPANY_NAME, lastof(buf));
+	b += seprintf(b, lastof(buf), ")");
+	return stredup(buf, lastof(buf));
+}
+
+char *DumpVehicleInfo(const Vehicle *v)
+{
+	char buf[256];
+	char *b = buf;
+	if (v) {
+		b += seprintf(b, lastof(buf), "veh: %u: (", v->index);
+		SetDParam(0, v->index);
+		b = GetString(b, STR_VEHICLE_NAME, lastof(buf));
+		if (v->First() && v->First() != v) {
+			b += seprintf(b, lastof(buf), "), front: %u: (", v->First()->index);
+			SetDParam(0, v->First()->index);
+			b = GetString(b, STR_VEHICLE_NAME, lastof(buf));
+		}
+		b += seprintf(b, lastof(buf), ")");
+	} else {
+		b += seprintf(b, lastof(buf), "veh: NULL");
+	}
+	return stredup(buf, lastof(buf));
+}
+
+#endif

src/scope_info.h

@@ -0,0 +1,58 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD 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, version 2.
+ * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file scope_info.h Scope info debug functions. */
+
+#ifndef SCOPE_INFO_H
+#define SCOPE_INFO_H
+
+#ifdef USE_SCOPE_INFO
+#include <functional>
+#include <vector>
+
+struct Vehicle;
+
+extern std::vector<std::function<int(char *, const char *)>> _scope_stack;
+
+struct scope_info_func_obj {
+	scope_info_func_obj(std::function<int(char *, const char *)> func)
+	{
+		_scope_stack.emplace_back(std::move(func));
+	}
+
+	scope_info_func_obj(const scope_info_func_obj &copysrc) = delete;
+
+	~scope_info_func_obj()
+	{
+		_scope_stack.pop_back();
+	}
+};
+
+int WriteScopeLog(char *buf, const char *last);
+
+#define SCOPE_INFO_PASTE(a, b) a ## b
+
+/**
+ * This creates a lambda in the current scope with the specified capture which outputs the given args as a format string.
+ * This lambda is then captured by reference in a std::function which is pushed onto the scope stack
+ * The scope stack is popped at the end of the scope
+ */
+#define SCOPE_INFO_FMT(capture, ...) auto SCOPE_INFO_PASTE(_sc_lm_, __LINE__) = capture (char *buf, const char *last) { return seprintf(buf, last, __VA_ARGS__); }; scope_info_func_obj SCOPE_INFO_PASTE(_sc_obj_, __LINE__) ([&](char *buf, const char *last) -> int { return SCOPE_INFO_PASTE(_sc_lm_, __LINE__) (buf, last); });
+
+// helper functions
+char *DumpCompanyInfo(int company_id);
+char *DumpVehicleInfo(const Vehicle *v);
+
+#else /* USE_SCOPE_INFO */
+
+#define SCOPE_INFO_FMT(...)
+
+#endif /* USE_SCOPE_INFO */
+
+#endif /* SCOPE_INFO_H */

src/stdafx.h

@@ -520,4 +520,10 @@ static inline void free(const void *ptr)
 	#define IGNORE_UNINITIALIZED_WARNING_STOP
 #endif
 
+#if !defined(DISABLE_SCOPE_INFO) && (__cplusplus >= 201103L || defined(__STDCXX_VERSION__) || defined(__GXX_EXPERIMENTAL_CXX0X__) || defined(__GXX_EXPERIMENTAL_CPP0X__))
+#define USE_SCOPE_INFO
+#endif
+
+#define SINGLE_ARG(...) __VA_ARGS__
+
 #endif /* STDAFX_H */