diff --git a/include/retdec/llvmir2hll/llvmir2hll.h b/include/retdec/llvmir2hll/llvmir2hll.h
index 7edcb25fad..224ea5278b 100644
--- a/include/retdec/llvmir2hll/llvmir2hll.h
+++ b/include/retdec/llvmir2hll/llvmir2hll.h
@@ -73,7 +73,6 @@
 #include "retdec/llvmir2hll/var_name_gen/var_name_gens/num_var_name_gen.h"
 #include "retdec/llvmir2hll/var_renamer/var_renamer.h"
 #include "retdec/llvmir2hll/var_renamer/var_renamer_factory.h"
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/utils/container.h"
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/memory.h"
diff --git a/include/retdec/llvmir2hll/optimizer/optimizer_manager.h b/include/retdec/llvmir2hll/optimizer/optimizer_manager.h
index 21f675279e..cd694fcc5a 100644
--- a/include/retdec/llvmir2hll/optimizer/optimizer_manager.h
+++ b/include/retdec/llvmir2hll/optimizer/optimizer_manager.h
@@ -10,7 +10,6 @@
 #include "retdec/llvmir2hll/optimizer/optimizer.h"
 #include "retdec/llvmir2hll/support/smart_ptr.h"
 #include "retdec/llvmir2hll/support/types.h"
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/utils/non_copyable.h"
 
 namespace retdec {
diff --git a/include/retdec/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.h b/include/retdec/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.h
index 462347de81..6868a34ecf 100644
--- a/include/retdec/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.h
+++ b/include/retdec/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.h
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "retdec/llvmir2hll/pattern/pattern_finder_runner.h"
+#include "retdec/utils/io/log.h"
 
 namespace retdec {
 namespace llvmir2hll {
@@ -23,7 +24,7 @@ namespace llvmir2hll {
 */
 class CLIPatternFinderRunner: public PatternFinderRunner {
 public:
-	CLIPatternFinderRunner(llvm::raw_ostream &os);
+	CLIPatternFinderRunner(utils::io::Logger &os);
 
 private:
 	virtual void doActionsBeforePatternFinderRuns(ShPtr<PatternFinder> pf) override;
@@ -34,7 +35,7 @@ class CLIPatternFinderRunner: public PatternFinderRunner {
 
 private:
 	/// Output stream, into which the patterns will be emitted.
-	llvm::raw_ostream &os;
+	utils::io::Logger &os;
 };
 
 } // namespace llvmir2hll
diff --git a/include/retdec/llvmir2hll/validator/validator.h b/include/retdec/llvmir2hll/validator/validator.h
index 9a840df8c7..e3f258c831 100644
--- a/include/retdec/llvmir2hll/validator/validator.h
+++ b/include/retdec/llvmir2hll/validator/validator.h
@@ -11,7 +11,9 @@
 
 #include "retdec/llvmir2hll/support/smart_ptr.h"
 #include "retdec/llvmir2hll/support/visitors/ordered_all_visitor.h"
-#include "retdec/llvm-support/diagnostics.h"
+#include "retdec/utils/io/log.h"
+
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace llvmir2hll {
@@ -49,8 +51,7 @@ class Validator: protected OrderedAllVisitor {
 	void validationError(const std::string &warningMessage, Args &&... args) {
 		moduleIsCorrect = false;
 		if (printMessageOnError) {
-			retdec::llvm_support::printWarningMessage(warningMessage,
-				std::forward<Args>(args)...);
+			Log::error() << Log::Warning << warningMessage << std::endl;
 		}
 	}
 
diff --git a/include/retdec/unpacker/plugin.h b/include/retdec/unpacker/plugin.h
index 23ff58d198..e72115929a 100644
--- a/include/retdec/unpacker/plugin.h
+++ b/include/retdec/unpacker/plugin.h
@@ -7,15 +7,17 @@
 #ifndef RETDEC_UNPACKER_PLUGIN_H
 #define RETDEC_UNPACKER_PLUGIN_H
 
-#include <iostream>
 #include <memory>
 #include <sstream>
 #include <string>
 
+#include "retdec/utils/io/log.h"
 #include "retdec/unpacker/unpacker_exception.h"
 
 #define plugin(T) retdec::unpackertool::Plugin::instance<T>()
 
+using namespace retdec::utils::io;
+
 namespace retdec {
 namespace unpackertool {
 
@@ -171,7 +173,7 @@ class Plugin
 	 */
 	template <typename... Args> void log(const Args&... args)
 	{
-		Plugin::logImpl(std::cout, "[", getInfo()->name, "] ", args...);
+		Plugin::logImpl(Log::info(), "[", getInfo()->name, "] ", args...);
 	}
 
 	/**
@@ -184,7 +186,7 @@ class Plugin
 	 */
 	template <typename... Args> void error(const Args&... args)
 	{
-		Plugin::logImpl(std::cerr, "[ERROR] [", getInfo()->name, "] ", args...);
+		Plugin::logImpl(Log::error(), "[ERROR] [", getInfo()->name, "] ", args...);
 	}
 
 	/**
@@ -211,13 +213,13 @@ class Plugin
 private:
 	PluginExitCode _cachedExitCode; ///< Cached exit code of the plugin for the unpacked file.
 
-	template <typename T, typename... Args> static void logImpl(std::ostream& out, const T& data, const Args&... args)
+	template <typename T, typename... Args> static void logImpl(Logger& out, const T& data, const Args&... args)
 	{
 		out << data;
 		logImpl(out, args...);
 	}
 
-	static void logImpl(std::ostream& out)
+	static void logImpl(Logger& out)
 	{
 		out << std::endl;
 	}
diff --git a/src/ar-extractortool/ar_extractor.cpp b/src/ar-extractortool/ar_extractor.cpp
index 852118632d..f14235d2a2 100644
--- a/src/ar-extractortool/ar_extractor.cpp
+++ b/src/ar-extractortool/ar_extractor.cpp
@@ -4,7 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <limits>
 #include <vector>
 
@@ -12,10 +11,12 @@
 #include <rapidjson/prettywriter.h>
 
 #include "retdec/utils/filesystem_path.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/ar-extractor/archive_wrapper.h"
 #include "retdec/ar-extractor/detection.h"
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace retdec::ar_extractor;
 using namespace rapidjson;
 
@@ -45,11 +46,10 @@ bool isJson = false;
  *
  * @param outputStream target stream
  */
-void printUsage(
-	std::ostream &outputStream)
+void printUsage(Logger& log)
 {
 
-	outputStream << "Usage: ar_extractor [OPTIONS] FILE\n\n"
+	log << "Usage: ar_extractor [OPTIONS] FILE\n\n"
 	"Options:\n\n"
 	"--arch-magic\n"
 	"    Check if file starts with archive magic constants.\n"
@@ -99,7 +99,7 @@ void printUsage(
 void printErrorPlainText(
 	const std::string &message)
 {
-	std::cerr << "Error: " << message << ".\n";
+	Log::error() << Log::Error << message << ".\n";
 }
 
 /**
@@ -120,7 +120,7 @@ void printErrorJson(
 	PrettyWriter<StringBuffer> writer(buffer);
 	errorFile.Accept(writer);
 
-	std::cerr << buffer.GetString() << "\n";
+	Log::error() << buffer.GetString() << "\n";
 }
 
 /**
@@ -163,7 +163,7 @@ int printTable(
 		}
 	}
 
-	std::cout << result;
+	Log::info() << result;
 	return 0;
 }
 
@@ -213,7 +213,7 @@ int processArguments(
 		const auto &arg = args[i];
 
 		if (arg == "-h" || arg == "--help") {
-			printUsage(std::cout);
+			printUsage(Log::info());
 			return 0;
 		}
 		else if (arg == "-o" || arg == "--output") {
@@ -339,7 +339,7 @@ int processArguments(
 			return printTable(archive, fixNames, isNum);
 
 		case ACTION::OBJECT_COUNT:
-			std::cout << archive.getNumberOfObjects() << "\n";
+			Log::info() << archive.getNumberOfObjects() << "\n";
 			return 0;
 
 		case ACTION::EXTRACT_NAME:
diff --git a/src/bin2llvmir/analyses/ctor_dtor.cpp b/src/bin2llvmir/analyses/ctor_dtor.cpp
index ebf1d7d771..013fcb73c9 100644
--- a/src/bin2llvmir/analyses/ctor_dtor.cpp
+++ b/src/bin2llvmir/analyses/ctor_dtor.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/Constants.h>
 #include <llvm/IR/Instruction.h>
 #include <llvm/IR/Instructions.h>
diff --git a/src/bin2llvmir/analyses/reaching_definitions.cpp b/src/bin2llvmir/analyses/reaching_definitions.cpp
index a3c3c8ba48..6c791a7ecd 100644
--- a/src/bin2llvmir/analyses/reaching_definitions.cpp
+++ b/src/bin2llvmir/analyses/reaching_definitions.cpp
@@ -5,7 +5,6 @@
 */
 
 #include <iomanip>
-#include <iostream>
 #include <set>
 #include <sstream>
 #include <string>
diff --git a/src/bin2llvmir/analyses/symbolic_tree.cpp b/src/bin2llvmir/analyses/symbolic_tree.cpp
index 9207ad2565..cdc61d6244 100644
--- a/src/bin2llvmir/analyses/symbolic_tree.cpp
+++ b/src/bin2llvmir/analyses/symbolic_tree.cpp
@@ -4,7 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <ostream>
 #include <sstream>
 
diff --git a/src/bin2llvmir/optimizations/asm_inst_remover/asm_inst_remover.cpp b/src/bin2llvmir/optimizations/asm_inst_remover/asm_inst_remover.cpp
index 5f260235ef..a657f970eb 100644
--- a/src/bin2llvmir/optimizations/asm_inst_remover/asm_inst_remover.cpp
+++ b/src/bin2llvmir/optimizations/asm_inst_remover/asm_inst_remover.cpp
@@ -5,8 +5,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include "retdec/bin2llvmir/optimizations/asm_inst_remover/asm_inst_remover.h"
 #include "retdec/bin2llvmir/providers/asm_instruction.h"
 #include "retdec/bin2llvmir/providers/names.h"
diff --git a/src/bin2llvmir/optimizations/class_hierarchy/hierarchy_analysis.cpp b/src/bin2llvmir/optimizations/class_hierarchy/hierarchy_analysis.cpp
index 00dc1a768f..fba0fc948f 100644
--- a/src/bin2llvmir/optimizations/class_hierarchy/hierarchy_analysis.cpp
+++ b/src/bin2llvmir/optimizations/class_hierarchy/hierarchy_analysis.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include "retdec/bin2llvmir/utils/llvm.h"
 #include "retdec/bin2llvmir/optimizations/class_hierarchy/hierarchy_analysis.h"
 #include "retdec/bin2llvmir/utils/debug.h"
diff --git a/src/bin2llvmir/optimizations/constants/constants.cpp b/src/bin2llvmir/optimizations/constants/constants.cpp
index 22b3aeb7b3..38ba873de4 100644
--- a/src/bin2llvmir/optimizations/constants/constants.cpp
+++ b/src/bin2llvmir/optimizations/constants/constants.cpp
@@ -6,7 +6,6 @@
 
 #include <cassert>
 #include <iomanip>
-#include <iostream>
 #include <set>
 #include <sstream>
 #include <string>
diff --git a/src/bin2llvmir/optimizations/decoder/decoder.cpp b/src/bin2llvmir/optimizations/decoder/decoder.cpp
index 7c7395e029..cec313b081 100644
--- a/src/bin2llvmir/optimizations/decoder/decoder.cpp
+++ b/src/bin2llvmir/optimizations/decoder/decoder.cpp
@@ -9,6 +9,7 @@
 
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/string.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/bin2llvmir/optimizations/decoder/decoder.h"
 #include "retdec/bin2llvmir/utils/llvm.h"
 #include "retdec/bin2llvmir/utils/capstone.h"
@@ -17,6 +18,7 @@ using namespace retdec::capstone2llvmir;
 using namespace retdec::common;
 using namespace retdec::bin2llvmir::st_match;
 using namespace retdec::fileformat;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace bin2llvmir {
@@ -88,7 +90,7 @@ bool Decoder::runCatcher()
 	}
 	catch (const BaseError& e)
 	{
-		std::cerr << "[capstone2llvmir]: " << e.what() << std::endl;
+		Log::error() << "[capstone2llvmir]: " << e.what() << std::endl;
 		exit(1);
 	}
 }
diff --git a/src/bin2llvmir/optimizations/idioms/idioms.cpp b/src/bin2llvmir/optimizations/idioms/idioms.cpp
index 502802dd5f..58056c4f4c 100644
--- a/src/bin2llvmir/optimizations/idioms/idioms.cpp
+++ b/src/bin2llvmir/optimizations/idioms/idioms.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include "retdec/bin2llvmir/optimizations/idioms/idioms.h"
 #include "retdec/bin2llvmir/optimizations/idioms/idioms_borland.h"
 #include "retdec/bin2llvmir/optimizations/idioms/idioms_common.h"
diff --git a/src/bin2llvmir/optimizations/idioms/idioms_magicdivmod.cpp b/src/bin2llvmir/optimizations/idioms/idioms_magicdivmod.cpp
index c899aa050c..65009ca29b 100644
--- a/src/bin2llvmir/optimizations/idioms/idioms_magicdivmod.cpp
+++ b/src/bin2llvmir/optimizations/idioms/idioms_magicdivmod.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/PatternMatch.h>
 
 #include "retdec/bin2llvmir/optimizations/idioms/idioms_magicdivmod.h"
diff --git a/src/bin2llvmir/optimizations/idioms_libgcc/idioms_libgcc.cpp b/src/bin2llvmir/optimizations/idioms_libgcc/idioms_libgcc.cpp
index 9369d2b953..ee1ece0140 100644
--- a/src/bin2llvmir/optimizations/idioms_libgcc/idioms_libgcc.cpp
+++ b/src/bin2llvmir/optimizations/idioms_libgcc/idioms_libgcc.cpp
@@ -4,7 +4,6 @@
 * @copyright (c) 2017 Avast Software, licensed under the MIT license
 */
 
-#include <iostream>
 #include <functional>
 
 #include <llvm/IR/InstIterator.h>
diff --git a/src/bin2llvmir/optimizations/param_return/param_return.cpp b/src/bin2llvmir/optimizations/param_return/param_return.cpp
index 44ada88cfd..e40da74f2e 100644
--- a/src/bin2llvmir/optimizations/param_return/param_return.cpp
+++ b/src/bin2llvmir/optimizations/param_return/param_return.cpp
@@ -6,7 +6,6 @@
 
 #include <cassert>
 #include <iomanip>
-#include <iostream>
 #include <limits>
 
 #include <llvm/IR/CFG.h>
diff --git a/src/bin2llvmir/optimizations/provider_init/provider_init.cpp b/src/bin2llvmir/optimizations/provider_init/provider_init.cpp
index 922359f83c..7b56a44cf3 100644
--- a/src/bin2llvmir/optimizations/provider_init/provider_init.cpp
+++ b/src/bin2llvmir/optimizations/provider_init/provider_init.cpp
@@ -4,11 +4,11 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <regex>
 
 #include <llvm/Support/CommandLine.h>
 
+#include "retdec/utils/io/log.h"
 #include "retdec/bin2llvmir/analyses/symbolic_tree.h"
 #include "retdec/bin2llvmir/optimizations/provider_init/provider_init.h"
 #include "retdec/bin2llvmir/providers/abi/abi.h"
@@ -24,6 +24,7 @@
 #include "retdec/yaracpp/yara_detector.h"
 
 using namespace llvm;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace bin2llvmir {
@@ -339,7 +340,7 @@ bool ProviderInitialization::runOnModule(Module& m)
 		{
 			if (l.bytecode)
 			{
-				std::cerr << "Warning: Detected " << l.name
+				Log::error() << Log::Warning << "Detected " << l.name
 						<< " bytecode, which cannot be decompiled by our "
 						"machine-code decompiler. "
 						"The decompilation result may be inaccurate.";
diff --git a/src/bin2llvmir/optimizations/select_functions/select_functions.cpp b/src/bin2llvmir/optimizations/select_functions/select_functions.cpp
index b5572bab6d..80d54f81bf 100644
--- a/src/bin2llvmir/optimizations/select_functions/select_functions.cpp
+++ b/src/bin2llvmir/optimizations/select_functions/select_functions.cpp
@@ -6,7 +6,6 @@
  */
 
 #include <iomanip>
-#include <iostream>
 
 #include <llvm/IR/Instruction.h>
 #include <llvm/IR/Instructions.h>
diff --git a/src/bin2llvmir/optimizations/simple_types/simple_types.cpp b/src/bin2llvmir/optimizations/simple_types/simple_types.cpp
index 80bd72fc84..e8a7a58540 100644
--- a/src/bin2llvmir/optimizations/simple_types/simple_types.cpp
+++ b/src/bin2llvmir/optimizations/simple_types/simple_types.cpp
@@ -5,7 +5,6 @@
 */
 
 #include <iomanip>
-#include <iostream>
 #include <queue>
 #include <set>
 #include <string>
diff --git a/src/bin2llvmir/optimizations/stack_pointer_ops/stack_pointer_ops.cpp b/src/bin2llvmir/optimizations/stack_pointer_ops/stack_pointer_ops.cpp
index 46cc291117..bcbdc699d3 100644
--- a/src/bin2llvmir/optimizations/stack_pointer_ops/stack_pointer_ops.cpp
+++ b/src/bin2llvmir/optimizations/stack_pointer_ops/stack_pointer_ops.cpp
@@ -6,7 +6,6 @@
 
 #include <cassert>
 #include <iomanip>
-#include <iostream>
 
 #include <llvm/IR/InstIterator.h>
 #include <llvm/IR/Instruction.h>
diff --git a/src/bin2llvmir/optimizations/syscalls/arm.cpp b/src/bin2llvmir/optimizations/syscalls/arm.cpp
index 38f018ccac..486a6be576 100644
--- a/src/bin2llvmir/optimizations/syscalls/arm.cpp
+++ b/src/bin2llvmir/optimizations/syscalls/arm.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/Constants.h>
 
 #include "retdec/bin2llvmir/optimizations/syscalls/syscalls.h"
diff --git a/src/bin2llvmir/optimizations/syscalls/mips.cpp b/src/bin2llvmir/optimizations/syscalls/mips.cpp
index 232d47fd86..4cbf76f568 100644
--- a/src/bin2llvmir/optimizations/syscalls/mips.cpp
+++ b/src/bin2llvmir/optimizations/syscalls/mips.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/Constants.h>
 
 #include "retdec/bin2llvmir/optimizations/syscalls/syscalls.h"
diff --git a/src/bin2llvmir/optimizations/syscalls/x86.cpp b/src/bin2llvmir/optimizations/syscalls/x86.cpp
index e6eb7c3cde..6527818e66 100644
--- a/src/bin2llvmir/optimizations/syscalls/x86.cpp
+++ b/src/bin2llvmir/optimizations/syscalls/x86.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/Constants.h>
 
 #include "retdec/bin2llvmir/optimizations/syscalls/syscalls.h"
diff --git a/src/bin2llvmir/optimizations/types_propagator/types_propagator.cpp b/src/bin2llvmir/optimizations/types_propagator/types_propagator.cpp
index dff20fdb7f..7d32ceaf1d 100644
--- a/src/bin2llvmir/optimizations/types_propagator/types_propagator.cpp
+++ b/src/bin2llvmir/optimizations/types_propagator/types_propagator.cpp
@@ -4,12 +4,14 @@
 * @copyright (c) 2020 Avast Software, licensed under the MIT license
 */
 
-#include <iostream>
 #include <optional>
 #include <queue>
 
+#include "retdec/utils/io/log.h"
 #include "retdec/bin2llvmir/optimizations/types_propagator/types_propagator.h"
 
+using namespace retdec::utils::io;
+
 namespace retdec {
 namespace bin2llvmir {
 
@@ -59,13 +61,13 @@ bool TypesPropagator::run()
 unsigned cntr = 0;
 for (auto& eq : _eqSets)
 {
-	std::cout << "set #" << cntr++ << std::endl;
+	Log::info() << "set #" << cntr++ << std::endl;
 	for (auto& v : eq)
 	{
 		if (llvm::isa<llvm::Function>(v))
-			std::cout << "\t\t" << v->getName().str() << std::endl;
+			Log::info() << "\t\t" << v->getName().str() << std::endl;
 		else
-			std::cout << "\t\t" << llvmObjToString(v) << std::endl;
+			Log::info() << "\t\t" << llvmObjToString(v) << std::endl;
 	}
 }
 exit(1);
diff --git a/src/bin2llvmir/optimizations/unreachable_funcs/unreachable_funcs.cpp b/src/bin2llvmir/optimizations/unreachable_funcs/unreachable_funcs.cpp
index f660202c8d..14c39e2e92 100644
--- a/src/bin2llvmir/optimizations/unreachable_funcs/unreachable_funcs.cpp
+++ b/src/bin2llvmir/optimizations/unreachable_funcs/unreachable_funcs.cpp
@@ -4,7 +4,6 @@
 * @copyright (c) 2017 Avast Software, licensed under the MIT license
 */
 
-#include <iostream>
 #include <string>
 
 #include <llvm/IR/Constants.h>
diff --git a/src/bin2llvmir/optimizations/writer_dsm/writer_dsm.cpp b/src/bin2llvmir/optimizations/writer_dsm/writer_dsm.cpp
index 39e1c511ad..64b65e38f8 100644
--- a/src/bin2llvmir/optimizations/writer_dsm/writer_dsm.cpp
+++ b/src/bin2llvmir/optimizations/writer_dsm/writer_dsm.cpp
@@ -8,7 +8,6 @@
 #include <cctype>
 #include <fstream>
 #include <iomanip>
-#include <iostream>
 #include <sstream>
 
 #include <llvm/IR/Instruction.h>
diff --git a/src/bin2llvmir/optimizations/x87_fpu/x87_fpu.cpp b/src/bin2llvmir/optimizations/x87_fpu/x87_fpu.cpp
index 75a2bdceb8..c1e851c59e 100644
--- a/src/bin2llvmir/optimizations/x87_fpu/x87_fpu.cpp
+++ b/src/bin2llvmir/optimizations/x87_fpu/x87_fpu.cpp
@@ -8,6 +8,7 @@
 #include <llvm/IR/InstIterator.h>
 #include <llvm/IR/Operator.h>
 
+#include "retdec/utils/io/log.h"
 #include "retdec/bin2llvmir/optimizations/x87_fpu/x87_fpu.h"
 #include "retdec/utils/string.h"
 #include "retdec/bin2llvmir/providers/asm_instruction.h"
@@ -20,6 +21,7 @@
 
 using namespace llvm;
 using namespace retdec::bin2llvmir::llvm_utils;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace bin2llvmir {
@@ -245,20 +247,20 @@ bool X87FpuAnalysis::run()
 
 void X87FpuAnalysis::printBlocksAnalyzeResult()
 {
-	std::cerr << "A*x=B\n";
+	Log::error() << "A*x=B\n";
 	for (auto& funMd: analyzedFunctionsMetadata)
 	{
-		std::cerr << funMd.function.getName().str() <<std::endl;
-		std::cerr << "A=\n" << funMd.A << "\nx=\n" << funMd.x << "\nB=\n" << funMd.B << "\n";
+		Log::error() << funMd.function.getName().str() <<std::endl;
+		Log::error() << "A=\n" << funMd.A << "\nx=\n" << funMd.x << "\nB=\n" << funMd.B << "\n";
 		for (Function::iterator functionI=funMd.function.begin(),
 			e = funMd.function.end(); functionI != e; ++functionI)
 		{
 			BasicBlock* bb = functionI.operator->();
 			int inputIndex = funMd.indexes[bb][funMd.inIndex];
 			int outputIndex = funMd.indexes[bb][funMd.outIndex];
-			std::cerr << bb->getName().str()<<":";
-			std::cerr << " (in=" << funMd.x(inputIndex, 0);;
-			std::cerr << ",out=" << funMd.x(outputIndex, 0) << ")\n";
+			Log::error() << bb->getName().str()<<":";
+			Log::error() << " (in=" << funMd.x(inputIndex, 0);;
+			Log::error() << ",out=" << funMd.x(outputIndex, 0) << ")\n";
 		}
 	}
 }
diff --git a/src/bin2llvmir/providers/config.cpp b/src/bin2llvmir/providers/config.cpp
index eeedbe2a02..44b1fd7972 100644
--- a/src/bin2llvmir/providers/config.cpp
+++ b/src/bin2llvmir/providers/config.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/GlobalVariable.h>
 #include <llvm/IR/Module.h>
 
diff --git a/src/bin2llvmir/providers/lti.cpp b/src/bin2llvmir/providers/lti.cpp
index e0b23019b0..0246811dfb 100644
--- a/src/bin2llvmir/providers/lti.cpp
+++ b/src/bin2llvmir/providers/lti.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <fstream>
-#include <iostream>
 
 #include "retdec/ctypes/floating_point_type.h"
 #include "retdec/ctypes/function_type.h"
diff --git a/src/bin2llvmir/utils/ir_modifier.cpp b/src/bin2llvmir/utils/ir_modifier.cpp
index fc1b7c54df..b44fc1b987 100644
--- a/src/bin2llvmir/utils/ir_modifier.cpp
+++ b/src/bin2llvmir/utils/ir_modifier.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/InstIterator.h>
 
 #include "retdec/utils/string.h"
diff --git a/src/bin2pat/bin2pat.cpp b/src/bin2pat/bin2pat.cpp
index 81522e85d6..21327cd66f 100644
--- a/src/bin2pat/bin2pat.cpp
+++ b/src/bin2pat/bin2pat.cpp
@@ -6,11 +6,11 @@
 
 #include <cstdlib>
 #include <fstream>
-#include <iostream>
 #include <ostream>
 #include <vector>
 
 #include "retdec/utils/filesystem_path.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/patterngen/pattern_extractor/pattern_extractor.h"
 #include "yaramod/yaramod.h"
 
@@ -22,12 +22,12 @@
  */
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace retdec::patterngen;
 
-void printUsage(
-	std::ostream &outputStream)
+void printUsage(Logger &log)
 {
-	outputStream << "Usage: bin2pat [-o OUTPUT_FILE] [-n NOTE]"
+	log << "Usage: bin2pat [-o OUTPUT_FILE] [-n NOTE]"
 		<< " <INPUT_FILE [INPUT_FILE...] | -l LIST_FILE>\n\n"
 		<< "-o --output OUTPUT_FILE\n"
 		<< "    Output file path (if not given, stdout is used).\n"
@@ -43,8 +43,8 @@ void printUsage(
 void printErrorAndDie(
 	const std::string &message)
 {
-	std::cerr << "Error: " << message << ".\n";
-	printUsage(std::cerr);
+	Log::error() << Log::Error << message << ".\n";
+	printUsage(Log::error());
 	std::exit(1);
 }
 
@@ -63,7 +63,7 @@ void processArgs(
 
 	for (std::size_t i = 0, e = args.size(); i < e; ++i) {
 		if (args[i] == "--help" || args[i] == "-h") {
-			printUsage(std::cout);
+			printUsage(Log::info());
 			return;
 		}
 		else if (args[i] == "-o" || args[i] == "--output") {
@@ -144,8 +144,8 @@ void processArgs(
 		if (!extractor.isValid()) {
 			// Sometimes, non-supported files are present in archives. We will
 			// only print warning if such a file is encountered.
-			std::cerr << "Error: file '" << path << "' was not processed.\n";
-			std::cerr << "Problem: " << extractor.getErrorMessage() << ".\n\n";
+			Log::error() << Log::Error << "file '" << path << "' was not processed.\n";
+			Log::error() << "Problem: " << extractor.getErrorMessage() << ".\n\n";
 			continue;
 		}
 		else {
@@ -155,11 +155,11 @@ void processArgs(
 			// Print warnings if any.
 			const auto &warnings = extractor.getWarnings();
 			if (!warnings.empty()) {
-				std::cerr << "Warning: problems with file '" << path << "'\n";
+				Log::error() << Log::Warning << "problems with file '" << path << "'\n";
 				for (const auto &warning : warnings) {
-					std::cerr << "Problem: " << warning << ".\n";
+					Log::error() << "Problem: " << warning << ".\n";
 				}
-				std::cerr << "\n";
+				Log::error() << "\n";
 			}
 		}
 	}
@@ -180,7 +180,7 @@ void processArgs(
 		outputFile << builder.get(false)->getText() << "\n";
 	}
 	else {
-		std::cout << builder.get(false)->getText() << "\n";
+		Log::info() << builder.get(false)->getText() << "\n";
 	}
 }
 
diff --git a/src/capstone2llvmir/arm/arm.cpp b/src/capstone2llvmir/arm/arm.cpp
index aa9b3edbd8..b18c904212 100644
--- a/src/capstone2llvmir/arm/arm.cpp
+++ b/src/capstone2llvmir/arm/arm.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <iomanip>
-#include <iostream>
 
 #include "capstone2llvmir/arm/arm_impl.h"
 
diff --git a/src/capstone2llvmir/arm64/arm64.cpp b/src/capstone2llvmir/arm64/arm64.cpp
index 30a5ee782e..a5e7c7e8d5 100644
--- a/src/capstone2llvmir/arm64/arm64.cpp
+++ b/src/capstone2llvmir/arm64/arm64.cpp
@@ -5,10 +5,13 @@
  */
 
 #include <iomanip>
-#include <iostream>
+
+#include "retdec/utils/io/log.h"
 
 #include "capstone2llvmir/arm64/arm64_impl.h"
 
+using namespace retdec::utils::io;
+
 namespace retdec {
 namespace capstone2llvmir {
 
@@ -704,7 +707,7 @@ llvm::Value* Capstone2LlvmIrTranslatorArm64_impl::loadRegister(
 		// If we dont find the register type, try to recover from this returning at
 		// least the number of register
 		// Maybe solve this better
-		std::cerr << e.what() << std::endl;
+		Log::error() << e.what() << std::endl;
 		return llvm::ConstantInt::get(dstType ? dstType : getDefaultType(), r);
 	}
 
@@ -818,7 +821,7 @@ llvm::Instruction* Capstone2LlvmIrTranslatorArm64_impl::storeRegister(
 	if (llvmReg == nullptr)
 	{
 		// Maybe return xchg eax, eax?
-		std::cerr << "storeRegister() unhandled reg." << std::endl;
+		Log::error() << "storeRegister() unhandled reg." << std::endl;
 		return nullptr;
 	}
 
diff --git a/src/capstone2llvmir/capstone2llvmir_impl.cpp b/src/capstone2llvmir/capstone2llvmir_impl.cpp
index 3f10248ba0..20231525d3 100644
--- a/src/capstone2llvmir/capstone2llvmir_impl.cpp
+++ b/src/capstone2llvmir/capstone2llvmir_impl.cpp
@@ -6,7 +6,6 @@
  */
 
 #include <iomanip>
-#include <iostream>
 
 #include "capstone2llvmir/capstone2llvmir_impl.h"
 
diff --git a/src/capstone2llvmir/llvmir_utils.cpp b/src/capstone2llvmir/llvmir_utils.cpp
index 99769bb6a2..d35ffecfe6 100644
--- a/src/capstone2llvmir/llvmir_utils.cpp
+++ b/src/capstone2llvmir/llvmir_utils.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2018 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include "capstone2llvmir/llvmir_utils.h"
 #include "retdec/capstone2llvmir/exceptions.h"
 
diff --git a/src/capstone2llvmir/mips/mips.cpp b/src/capstone2llvmir/mips/mips.cpp
index 695aa8b8f6..bd16706a18 100644
--- a/src/capstone2llvmir/mips/mips.cpp
+++ b/src/capstone2llvmir/mips/mips.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <iomanip>
-#include <iostream>
 
 #include "capstone2llvmir/mips/mips_impl.h"
 
diff --git a/src/capstone2llvmir/powerpc/powerpc.cpp b/src/capstone2llvmir/powerpc/powerpc.cpp
index 9696a055de..886bc3283b 100644
--- a/src/capstone2llvmir/powerpc/powerpc.cpp
+++ b/src/capstone2llvmir/powerpc/powerpc.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <iomanip>
-#include <iostream>
 
 #include "capstone2llvmir/powerpc/powerpc_impl.h"
 
diff --git a/src/capstone2llvmir/x86/x86.cpp b/src/capstone2llvmir/x86/x86.cpp
index ced4fc3ffe..83717eb286 100644
--- a/src/capstone2llvmir/x86/x86.cpp
+++ b/src/capstone2llvmir/x86/x86.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <iomanip>
-#include <iostream>
 
 #include "capstone2llvmir/x86/x86_impl.h"
 
diff --git a/src/capstone2llvmirtool/capstone2llvmir.cpp b/src/capstone2llvmirtool/capstone2llvmir.cpp
index e59020babd..6c67a8c90a 100644
--- a/src/capstone2llvmirtool/capstone2llvmir.cpp
+++ b/src/capstone2llvmirtool/capstone2llvmir.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <iomanip>
-#include <iostream>
 
 #include <keystone/keystone.h>
 #include <llvm/IR/Module.h>
@@ -143,7 +142,7 @@ class ProgramOptions
 				case CS_ARCH_MAX:
 				case CS_ARCH_ALL:
 				default:
-					std::cerr << "Can not get Capstone arch to default Capstone basic mode." << std::endl;
+					Log::error() << "Can not get Capstone arch to default Capstone basic mode." << std::endl;
 					exit(1);
 			}
 		}
@@ -152,23 +151,23 @@ class ProgramOptions
 		{
 			std::string tmp;
 			retdec::utils::bytesToHexString(code, tmp, 0, 0, false, true);
-			std::cout << std::endl;
-			std::cout << "Program Options:" << std::endl;
-			std::cout << "\t" << "arch   : " << arch << " (" << _arch << ")" << std::endl;
-			std::cout << "\t" << "base   : " << std::hex << base << " (" << _base << ")" << std::endl;
-			std::cout << "\t" << "code   : " << tmp << " (" << _code << ")" << std::endl;
-			std::cout << "\t" << "asm text : " << text << std::endl;
-			std::cout << "\t" << "b mode : " << std::hex << basicMode << " (" << _basicMode << ")" << std::endl;
-			std::cout << "\t" << "e mode : " << std::hex << extraMode << " (" << _extraMode << ")" << std::endl;
-			std::cout << "\t" << "out    : " << outFile << std::endl;
-			std::cout << std::endl;
+			Log::info() << std::endl;
+			Log::info() << "Program Options:" << std::endl;
+			Log::info() << "\t" << "arch   : " << arch << " (" << _arch << ")" << std::endl;
+			Log::info() << "\t" << "base   : " << std::hex << base << " (" << _base << ")" << std::endl;
+			Log::info() << "\t" << "code   : " << tmp << " (" << _code << ")" << std::endl;
+			Log::info() << "\t" << "asm text : " << text << std::endl;
+			Log::info() << "\t" << "b mode : " << std::hex << basicMode << " (" << _basicMode << ")" << std::endl;
+			Log::info() << "\t" << "e mode : " << std::hex << extraMode << " (" << _extraMode << ")" << std::endl;
+			Log::info() << "\t" << "out    : " << outFile << std::endl;
+			Log::info() << std::endl;
 		}
 
 		void printHelpAndDie()
 		{
 			std::string tmp;
 			retdec::utils::bytesToHexString(CODE, tmp, 0, 0, false, true);
-			std::cout << _programName << ":\n"
+			Log::info() << _programName << ":\n"
 				"\t-a name   Set architecture name.\n"
 				"\t          Possible values: arm, arm64, mips, x86, ppc, sparc, sysz, xcore\n"
 				"\t          Default value: x86.\n"
@@ -220,8 +219,8 @@ void printVersion()
 	int minor = 0;
 	int version = cs_version(&major, &minor);
 
-	std::cout << std::endl;
-	std::cout << "Capstone version: " << version << " (major: " << major
+	Log::info() << std::endl;
+	Log::info() << "Capstone version: " << version << " (major: " << major
 			<< ", minor: " << minor << ")" << std::endl;
 }
 
@@ -240,7 +239,7 @@ ks_arch capstoneArchToKeystoneArch(cs_arch a)
 		case CS_ARCH_MAX:
 		case CS_ARCH_ALL:
 		default:
-			std::cerr << "Can not convert Capstone arch to Keystone arch." << std::endl;
+			Log::error() << "Can not convert Capstone arch to Keystone arch." << std::endl;
 			exit(1);
 	}
 }
@@ -283,7 +282,7 @@ ks_mode capstoneModeBasicToKeystoneMode(cs_arch a, cs_mode m)
 	}
 	else
 	{
-		std::cerr << "Can not convert Capstone basic mode to Keystone mode." << std::endl;
+		Log::error() << "Can not convert Capstone basic mode to Keystone mode." << std::endl;
 		exit(1);
 	}
 }
@@ -316,7 +315,7 @@ ks_mode capstoneModeExtraToKeystoneMode(cs_arch a, cs_mode m)
 	}
 	else
 	{
-		std::cerr << "Can not convert Capstone extra mode to Keystone mode." << std::endl;
+		Log::error() << "Can not convert Capstone extra mode to Keystone mode." << std::endl;
 		exit(1);
 	}
 }
@@ -335,7 +334,7 @@ void assemble(ProgramOptions& po)
 	if (ks_open(arch, basic | extra, &ks) != KS_ERR_OK)
 	{
 		ks_err err = ks_errno(ks);
-		std::cerr << "Keystone Error: " << ks_strerror(err) << std::endl;
+		Log::error() << Log::Error << "Keystone: " << ks_strerror(err) << std::endl;
 		exit(1);
 	}
 
@@ -346,7 +345,7 @@ void assemble(ProgramOptions& po)
 	if (ks_asm(ks, po.text.data(), po.base, &enc, &sz, &cnt) != KS_ERR_OK)
 	{
 		ks_err err = ks_errno(ks);
-		std::cerr << "Keystone Error: " << ks_strerror(err) << std::endl;
+		Log::error() << Log::Error << "Keystone: " << ks_strerror(err) << std::endl;
 		exit(1);
 	}
 
@@ -361,7 +360,7 @@ void assemble(ProgramOptions& po)
 	if (ks_close(ks) != KS_ERR_OK)
 	{
 		ks_err err = ks_errno(ks);
-		std::cerr << "Keystone Error: " << ks_strerror(err) << std::endl;
+		Log::error() << Log::Error << "Keystone : " << ks_strerror(err) << std::endl;
 		exit(1);
 	}
 }
@@ -404,12 +403,12 @@ int main(int argc, char *argv[])
 	}
 	catch (const BaseError& e)
 	{
-		std::cerr << e.what() << std::endl;
+		Log::error() << e.what() << std::endl;
 		assert(false);
 	}
 	catch (...)
 	{
-		std::cerr << "Some unhandled exception" << std::endl;
+		Log::error() << "Some unhandled exception" << std::endl;
 	}
 
 	std::error_code ec;
diff --git a/src/common/address.cpp b/src/common/address.cpp
index 6edfd591fb..510eb0a0cf 100644
--- a/src/common/address.cpp
+++ b/src/common/address.cpp
@@ -7,7 +7,6 @@
 #include <cassert>
 #include <climits>
 #include <cstdio>
-#include <iostream>
 #include <vector>
 
 #include "retdec/common/address.h"
diff --git a/src/debugformat/debugformat.cpp b/src/debugformat/debugformat.cpp
index dcceb78571..b4e397ca1c 100644
--- a/src/debugformat/debugformat.cpp
+++ b/src/debugformat/debugformat.cpp
@@ -6,7 +6,6 @@
 
 #define LOG_ENABLED false
 
-#include <iostream>
 #include <sstream>
 
 #include "retdec/utils/debug.h"
diff --git a/src/debugformat/dwarf.cpp b/src/debugformat/dwarf.cpp
index cb8875f970..387867e755 100644
--- a/src/debugformat/dwarf.cpp
+++ b/src/debugformat/dwarf.cpp
@@ -6,8 +6,6 @@
 
 #define LOG_ENABLED false
 
-#include <iostream>
-
 #include <llvm/DebugInfo/DWARF/DWARFExpression.h>
 
 #include "retdec/demangler/demangler.h"
diff --git a/src/debugformat/pdb.cpp b/src/debugformat/pdb.cpp
index 2415b77e86..2397f38cd3 100644
--- a/src/debugformat/pdb.cpp
+++ b/src/debugformat/pdb.cpp
@@ -6,8 +6,6 @@
 
 #define LOG_ENABLED false
 
-#include <iostream>
-
 #include "retdec/debugformat/debugformat.h"
 
 namespace retdec {
diff --git a/src/demanglertool/demangler.cpp b/src/demanglertool/demangler.cpp
index c2bc0eb6f6..ef7a72ba15 100644
--- a/src/demanglertool/demangler.cpp
+++ b/src/demanglertool/demangler.cpp
@@ -9,6 +9,10 @@
 
 #include "retdec/demangler/demangler.h"
 
+#include "retdec/utils/io/log.h"
+
+using namespace retdec::utils::io;
+
 using ItaniumDemangler = retdec::demangler::ItaniumDemangler;
 using MicrosoftDemangler = retdec::demangler::MicrosoftDemangler;
 using BorlandDemangler = retdec::demangler::BorlandDemangler;
@@ -35,7 +39,7 @@ int main(int argc, char *argv[])
 	std::string demangledBorland;
 
 	if (argc <= 1 || strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "--help") == 0) {
-		std::cout << helpmsg;
+		Log::info() << helpmsg;
 		return 0;
 	}
 
@@ -47,13 +51,13 @@ int main(int argc, char *argv[])
 		demangledBorland = dem_borland->demangleToString(argv[i]);
 
 		if (!demangledGcc.empty()) {
-			std::cout << "gcc: " << demangledGcc << std::endl;
+			Log::info() << "gcc: " << demangledGcc << std::endl;
 		}
 		if (!demangledMs.empty()) {
-			std::cout << "ms: " << demangledMs << std::endl;
+			Log::info() << "ms: " << demangledMs << std::endl;
 		}
 		if (!demangledBorland.empty()) {
-			std::cout << "borland: " << demangledBorland << std::endl;
+			Log::info() << "borland: " << demangledBorland << std::endl;
 		}
 	}
 
diff --git a/src/fileformat/file_format/file_format.cpp b/src/fileformat/file_format/file_format.cpp
index 3377dd9933..bed1220a1f 100644
--- a/src/fileformat/file_format/file_format.cpp
+++ b/src/fileformat/file_format/file_format.cpp
@@ -9,13 +9,13 @@
 #include <climits>
 #include <cstring>
 #include <functional>
-#include <iostream>
 #include <sstream>
 
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/file_io.h"
 #include "retdec/utils/string.h"
 #include "retdec/utils/system.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/fileformat/file_format/file_format.h"
 #include "retdec/fileformat/utils/byte_array_buffer.h"
 #include "retdec/fileformat/file_format/intel_hex/intel_hex_format.h"
@@ -28,6 +28,7 @@
 #include "retdec/pelib/PeLibInc.h"
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace PeLib;
 
 namespace retdec {
@@ -2336,7 +2337,7 @@ void FileFormat::dump()
 {
 	std::string output;
 	dump(output);
-	std::cout << output;
+	Log::info() << output;
 }
 
 /**
@@ -2561,7 +2562,7 @@ void FileFormat::dumpRegionsValidity()
 {
 	std::string output;
 	dumpRegionsValidity(output);
-	std::cout << output;
+	Log::info() << output;
 }
 
 /**
@@ -2603,7 +2604,7 @@ void FileFormat::dumpResourceTree()
 {
 	std::string output;
 	dumpResourceTree(output);
-	std::cout << output;
+	Log::info() << output;
 }
 
 void FileFormat::dumpResourceTree(std::string &dumpStr)
diff --git a/src/fileformat/types/dotnet_types/dotnet_type_reconstructor.cpp b/src/fileformat/types/dotnet_types/dotnet_type_reconstructor.cpp
index 89eb68dfd0..e498cbd2e2 100644
--- a/src/fileformat/types/dotnet_types/dotnet_type_reconstructor.cpp
+++ b/src/fileformat/types/dotnet_types/dotnet_type_reconstructor.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/string.h"
 #include "retdec/fileformat/types/dotnet_headers/metadata_tables.h"
diff --git a/src/fileformat/types/resource_table/resource_table.cpp b/src/fileformat/types/resource_table/resource_table.cpp
index 6874e07bdf..aab94fb5ad 100644
--- a/src/fileformat/types/resource_table/resource_table.cpp
+++ b/src/fileformat/types/resource_table/resource_table.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <sstream>
-#include <iostream>
 
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/dynamic_buffer.h"
diff --git a/src/fileformat/utils/byte_array_buffer.cpp b/src/fileformat/utils/byte_array_buffer.cpp
index a42472911f..c40da9d8ee 100644
--- a/src/fileformat/utils/byte_array_buffer.cpp
+++ b/src/fileformat/utils/byte_array_buffer.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2019 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <functional>
 #include <cassert>
 #include <cstring>
diff --git a/src/fileinfo/file_presentation/json_presentation.cpp b/src/fileinfo/file_presentation/json_presentation.cpp
index de25779ebe..d2597e71e0 100644
--- a/src/fileinfo/file_presentation/json_presentation.cpp
+++ b/src/fileinfo/file_presentation/json_presentation.cpp
@@ -4,10 +4,9 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/string.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/fileformat/utils/conversions.h"
 #include "retdec/serdes/pattern.h"
 #include "retdec/serdes/std.h"
@@ -17,6 +16,7 @@
 
 using namespace retdec;
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace retdec::cpdetect;
 using namespace retdec::fileformat;
 
@@ -1285,7 +1285,7 @@ bool JsonPresentation::present()
 	presentIterativeSubtitle(writer, StringsJsonGetter(fileinfo));
 
 	writer.EndObject();
-	std::cout << sb.GetString() << std::endl;
+	Log::info() << sb.GetString() << std::endl;
 
 	return true;
 }
diff --git a/src/fileinfo/file_presentation/plain_presentation.cpp b/src/fileinfo/file_presentation/plain_presentation.cpp
index d78140b5d8..dbea59ebb5 100644
--- a/src/fileinfo/file_presentation/plain_presentation.cpp
+++ b/src/fileinfo/file_presentation/plain_presentation.cpp
@@ -4,15 +4,15 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include "retdec/utils/string.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/fileformat/utils/conversions.h"
 #include "fileinfo/file_presentation/getters/format.h"
 #include "fileinfo/file_presentation/getters/plain_getters.h"
 #include "fileinfo/file_presentation/plain_presentation.h"
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace retdec::cpdetect;
 using namespace retdec::fileformat;
 
@@ -33,7 +33,7 @@ void presentTitle(const std::string &title)
 	const auto pos = title.find_first_not_of(" ");
 	if(pos != std::string::npos)
 	{
-		std::cout << "\n\n" << title << "\n" << std::string(pos, ' ') << std::string(title.length() - pos, '-') << "\n";
+		Log::info() << "\n\n" << title << "\n" << std::string(pos, ' ') << std::string(title.length() - pos, '-') << "\n";
 	}
 }
 
@@ -62,10 +62,10 @@ void presentSimple(const std::vector<std::string> &desc, const std::vector<std::
 		{
 			if(space)
 			{
-				std::cout << "\n";
+				Log::info() << "\n";
 				space = false;
 			}
-			std::cout << desc[i] << info[i] << "\n";
+			Log::info() << desc[i] << info[i] << "\n";
 		}
 	}
 }
@@ -145,7 +145,7 @@ void presentIterativeDistributionHeader(const IterativeDistributionGetter &gette
 	std::string header, separator;
 	getter.getHeader(structIndex, header);
 	const auto wSpaces = getIterativeDistributionSeparator(getter, separator, structIndex);
-	std::cout << "\n" << header << "\n" << separator << "\n";
+	Log::info() << "\n" << header << "\n" << separator << "\n";
 	if(!explanatory)
 	{
 		return;
@@ -166,11 +166,11 @@ void presentIterativeDistributionHeader(const IterativeDistributionGetter &gette
 	{
 		if(abbv[i].find_first_not_of(" ") != std::string::npos && desc[i].find_first_not_of(" ") != std::string::npos)
 		{
-			std::cout << std::string(wSpaces, ' ') << abbv[i] << std::string(maxLen - lens[i], ' ') << " - " << desc[i] << "\n";
+			Log::info() << std::string(wSpaces, ' ') << abbv[i] << std::string(maxLen - lens[i], ' ') << " - " << desc[i] << "\n";
 		}
 	}
 
-	std::cout << separator << "\n" << header << "\n" << separator << "\n";
+	Log::info() << separator << "\n" << header << "\n" << separator << "\n";
 }
 
 /**
@@ -200,7 +200,7 @@ void presentIterativeDistributionStructure(const IterativeDistributionGetter &ge
 	{
 		if(!desc[i].empty() && !info[i].empty())
 		{
-			std::cout << desc[i] << info[i] << "\n";
+			Log::info() << desc[i] << info[i] << "\n";
 		}
 	}
 
@@ -241,14 +241,14 @@ void presentIterativeDistributionStructure(const IterativeDistributionGetter &ge
 			}
 			else
 			{
-				std::cout << line << value << "\n";
+				Log::info() << line << value << "\n";
 				line = std::string(line.length() + distribution[j], ' ');
 			}
 		}
 
 		if(line != std::string(line.length(), ' '))
 		{
-			std::cout << line << "\n";
+			Log::info() << line << "\n";
 		}
 	}
 
@@ -260,11 +260,11 @@ void presentIterativeDistributionStructure(const IterativeDistributionGetter &ge
 	if((len = info.size()))
 	{
 		getIterativeDistributionSeparator(getter, line, structIndex);
-		std::cout << line << "\nFlags:\n";
+		Log::info() << line << "\nFlags:\n";
 
 		for(std::size_t i = 0; i < len; ++i)
 		{
-			std::cout << "  " << info[i] << " - " << desc[i] << "\n";
+			Log::info() << "  " << info[i] << " - " << desc[i] << "\n";
 		}
 	}
 }
@@ -308,7 +308,7 @@ void presentIterativeSimpleStructure(const IterativeSimpleGetter &getter, std::s
 	{
 		if(!desc[i].empty() && !info[i].empty())
 		{
-			std::cout << desc[i] << info[i] << "\n";
+			Log::info() << desc[i] << info[i] << "\n";
 		}
 	}
 
@@ -321,7 +321,7 @@ void presentIterativeSimpleStructure(const IterativeSimpleGetter &getter, std::s
 
 	for(std::size_t i = 0; getter.getRecord(structIndex, i, info); ++i)
 	{
-		std::cout << '\n' << elemHeader << " #" << i << std::endl;
+		Log::info() << '\n' << elemHeader << " #" << i << std::endl;
 		presentSimple(desc, info, false);
 	}
 }
@@ -358,29 +358,29 @@ void PlainPresentation::presentCompiler() const
 	{
 		const DetectResult& tool = fileinfo.toolInfo.detectedTools[i];
 
-		std::cout << "Detected tool            : " << tool.name;
+		Log::info() << "Detected tool            : " << tool.name;
 		if (!tool.versionInfo.empty())
 		{
-			std::cout << " (" << tool.versionInfo << ")";
+			Log::info() << " (" << tool.versionInfo << ")";
 		}
 		if (!tool.additionalInfo.empty())
 		{
-			std::cout << " " << tool.additionalInfo;
+			Log::info() << " " << tool.additionalInfo;
 		}
-		std::cout << " (" << toolTypeToString(tool.type) << ")";
+		Log::info() << " (" << toolTypeToString(tool.type) << ")";
 		if (tool.source == DetectionMethod::SIGNATURE)
 		{
 			std::string nibbles = tool.impCount ? "nibbles" : "nibble";
 			auto ratio = static_cast<double>(tool.agreeCount) / tool.impCount * 100;
 
-			std::cout << ", " << tool.agreeCount << " from " << tool.impCount << " significant " << nibbles;
-			std::cout << " (" << ratio << "%)";
+			Log::info() << ", " << tool.agreeCount << " from " << tool.impCount << " significant " << nibbles;
+			Log::info() << " (" << ratio << "%)";
 		}
 		else
 		{
-			std::cout << ", " << detectionMetodToString(tool.source);
+			Log::info() << ", " << detectionMetodToString(tool.source);
 		}
-		std::cout << "\n";
+		Log::info() << "\n";
 	}
 }
 
@@ -394,26 +394,26 @@ void PlainPresentation::presentLanguages() const
 	{
 		return;
 	}
-	std::cout << "Original language        : ";
+	Log::info() << "Original language        : ";
 
 	for(std::size_t i = 0; i < noOfLanguages; )
 	{
-		std::cout << fileinfo.toolInfo.detectedLanguages[i].name;
+		Log::info() << fileinfo.toolInfo.detectedLanguages[i].name;
 		if(fileinfo.toolInfo.detectedLanguages[i].additionalInfo.length())
 		{
-			std::cout << " (" << fileinfo.toolInfo.detectedLanguages[i].additionalInfo << ")";
+			Log::info() << " (" << fileinfo.toolInfo.detectedLanguages[i].additionalInfo << ")";
 		}
 		if(fileinfo.toolInfo.detectedLanguages[i].bytecode)
 		{
-			std::cout << " (bytecode)";
+			Log::info() << " (bytecode)";
 		}
 		if(++i < noOfLanguages)
 		{
-			std::cout << ", ";
+			Log::info() << ", ";
 		}
 	}
 
-	std::cout << "\n";
+	Log::info() << "\n";
 }
 
 /**
@@ -426,11 +426,11 @@ void PlainPresentation::presentRichHeader() const
 	const auto sig = toLower(fileinfo.getRichHeaderSignature());
 	if(!offset.empty())
 	{
-		std::cout << "Rich header offset       : " << offset << "\n";
+		Log::info() << "Rich header offset       : " << offset << "\n";
 	}
 	if(!key.empty())
 	{
-		std::cout << "Rich header key          : " << key << "\n";
+		Log::info() << "Rich header key          : " << key << "\n";
 	}
 	if(!sig.empty())
 	{
@@ -441,7 +441,7 @@ void PlainPresentation::presentRichHeader() const
 
 		for(std::size_t i = 0, e = sig.length(); i < e; i += signLineLen)
 		{
-			std::cout << (i ? std::string(signDesc.length(), ' ') : signDesc) << sig.substr(i, signLineLen) << "\n";
+			Log::info() << (i ? std::string(signDesc.length(), ' ') : signDesc) << sig.substr(i, signLineLen) << "\n";
 		}
 	}
 }
@@ -456,15 +456,15 @@ void PlainPresentation::presentOverlay() const
 	const auto entropy = fileinfo.getOverlayEntropyStr(truncFloat);
 	if(!offset.empty())
 	{
-		std::cout << "Overlay offset           : " << offset << "\n";
+		Log::info() << "Overlay offset           : " << offset << "\n";
 	}
 	if(!size.empty())
 	{
-		std::cout << "Overlay size             : " << size << "\n";
+		Log::info() << "Overlay size             : " << size << "\n";
 	}
 	if(!entropy.empty())
 	{
-		std::cout << "Overlay entropy          : " << entropy << "\n";
+		Log::info() << "Overlay entropy          : " << entropy << "\n";
 	}
 }
 
@@ -474,7 +474,7 @@ void PlainPresentation::presentOverlay() const
 void PlainPresentation::presentPackingInfo() const
 {
 	const auto packed = fileinfo.toolInfo.isPacked();
-	std::cout << "Packed                   : " << packedToString(packed) << "\n";
+	Log::info() << "Packed                   : " << packedToString(packed) << "\n";
 }
 
 /**
@@ -491,18 +491,18 @@ void PlainPresentation::presentSimpleFlags(const std::string &title, const std::
 		return;
 	}
 
-	std::cout << title << flags;
+	Log::info() << title << flags;
 	const std::string abbreviations = abbvSerialization(abbv);
 	if(!abbreviations.empty())
 	{
-		flags.empty() ? std::cout << abbreviations : std::cout << " (" << abbreviations << ")";
+		flags.empty() ? Log::info() << abbreviations : Log::info() << " (" << abbreviations << ")";
 	}
-	std::cout << "\n";
+	Log::info() << "\n";
 	if(explanatory)
 	{
 		for(std::size_t i = 0, e = abbv.size(); i < e; ++i)
 		{
-			std::cout << "  " << abbv[i] << " - " << desc[i] << "\n";
+			Log::info() << "  " << abbv[i] << " - " << desc[i] << "\n";
 		}
 	}
 }
@@ -520,31 +520,31 @@ void PlainPresentation::presentPatterns(const std::string &title, const std::vec
 	}
 
 	presentTitle(title);
-	std::cout << "Number of detected patterns: " << patterns.size() << "\n\n";
+	Log::info() << "Number of detected patterns: " << patterns.size() << "\n\n";
 
 	for(std::size_t i = 0, e = patterns.size(); i < e; ++i)
 	{
-		std::cout << patterns[i].getYaraRuleName() << "\n";
+		Log::info() << patterns[i].getYaraRuleName() << "\n";
 		const auto description = patterns[i].getDescription();
 		if(!description.empty())
 		{
-			std::cout << "  description: " << description << "\n";
+			Log::info() << "  description: " << description << "\n";
 		}
 		if(patterns[i].isLittle() || patterns[i].isBig())
 		{
 			const std::string end = patterns[i].isLittle() ? "little" : "big";
-			std::cout << "  endianness: " << end << "\n";
+			Log::info() << "  endianness: " << end << "\n";
 		}
-		std::cout << "  number of matches: " << patterns[i].getNumberOfMatches();
+		Log::info() << "  number of matches: " << patterns[i].getNumberOfMatches();
 		const auto &matches = patterns[i].getMatches();
 		presentIterativeDistribution(PatternMatchesPlainGetter(fileinfo, matches), explanatory);
 		if(matches.empty())
 		{
-			std::cout << "\n";
+			Log::info() << "\n";
 		}
 		if(i + 1 != e)
 		{
-			std::cout << "\n";
+			Log::info() << "\n";
 		}
 	}
 }
@@ -555,10 +555,10 @@ void PlainPresentation::presentDotnetClasses() const
 	if (classes.empty())
 		return;
 
-	std::cout << '\n';
+	Log::info() << '\n';
 	for (const auto& dotnetClass : classes)
 	{
-		std::cout << dotnetClass->getVisibilityString() << ' '
+		Log::info() << dotnetClass->getVisibilityString() << ' '
 			<< (dotnetClass->isAbstract() ? "abstract " : "")
 			<< (dotnetClass->isSealed() ? "sealed " : "")
 			<< dotnetClass->getTypeString() << ' '
@@ -566,23 +566,23 @@ void PlainPresentation::presentDotnetClasses() const
 
 		if (!dotnetClass->getBaseTypes().empty())
 		{
-			std::cout << " : ";
+			Log::info() << " : ";
 			for (auto itr = dotnetClass->getBaseTypes().begin(), end = dotnetClass->getBaseTypes().end(); itr != end; ++itr)
 			{
-				std::cout << (*itr)->getText();
+				Log::info() << (*itr)->getText();
 				if (itr + 1 != end)
-					std::cout << ", ";
+					Log::info() << ", ";
 			}
 		}
 
-		std::cout << '\n';
+		Log::info() << '\n';
 
 		if (!dotnetClass->getMethods().empty())
-			std::cout << "    // Methods\n";
+			Log::info() << "    // Methods\n";
 
 		for (const auto& dotnetMethod : dotnetClass->getMethods())
 		{
-			std::cout << "    " << dotnetMethod->getVisibilityString() << ' '
+			Log::info() << "    " << dotnetMethod->getVisibilityString() << ' '
 				<< (dotnetMethod->isStatic() ? "static " : "")
 				<< (dotnetMethod->isVirtual() ? "virtual " : "")
 				<< (dotnetMethod->isFinal() ? "sealed " : "")
@@ -593,31 +593,31 @@ void PlainPresentation::presentDotnetClasses() const
 
 			for (auto itr = dotnetMethod->getParameters().begin(), end = dotnetMethod->getParameters().end(); itr != end; ++itr)
 			{
-				std::cout << (*itr)->getDataType()->getText() << ' ' << (*itr)->getName();
+				Log::info() << (*itr)->getDataType()->getText() << ' ' << (*itr)->getName();
 				if (itr + 1 != end)
-					std::cout << ", ";
+					Log::info() << ", ";
 			}
 
-			std::cout << ")\n";
+			Log::info() << ")\n";
 		}
 
 		if (!dotnetClass->getFields().empty())
-			std::cout << "    // Fields\n";
+			Log::info() << "    // Fields\n";
 
 		for (const auto& dotnetField : dotnetClass->getFields())
 		{
-			std::cout << "    " << dotnetField->getVisibilityString() << ' '
+			Log::info() << "    " << dotnetField->getVisibilityString() << ' '
 				<< dotnetField->getDataType()->getText() << ' '
 				<< dotnetField->getName()
 				<< '\n';
 		}
 
 		if (!dotnetClass->getProperties().empty())
-			std::cout << "    // Properties\n";
+			Log::info() << "    // Properties\n";
 
 		for (const auto& dotnetProperty : dotnetClass->getProperties())
 		{
-			std::cout << "    " << dotnetProperty->getVisibilityString() << ' '
+			Log::info() << "    " << dotnetProperty->getVisibilityString() << ' '
 				<< dotnetProperty->getDataType()->getText() << ' '
 				<< dotnetProperty->getName()
 				<< '\n';
@@ -634,14 +634,14 @@ void PlainPresentation::presentVisualBasicObjects() const
 		return;
 	}
 
-	std::cout << "\n";
-	std::cout << "Visual Basic Object table" << "\n";
-	std::cout << "-------------------------" << "\n";
-	std::cout << "CRC32            : " << fileinfo.getVisualBasicObjectTableHashCrc32() << "\n";
-	std::cout << "MD5              : " << fileinfo.getVisualBasicObjectTableHashMd5() << "\n";
-	std::cout << "SHA256           : " << fileinfo.getVisualBasicObjectTableHashSha256() << "\n";
-	std::cout << "GUID             : " << guid << "\n";
-	std::cout << "\n";
+	Log::info() << "\n";
+	Log::info() << "Visual Basic Object table" << "\n";
+	Log::info() << "-------------------------" << "\n";
+	Log::info() << "CRC32            : " << fileinfo.getVisualBasicObjectTableHashCrc32() << "\n";
+	Log::info() << "MD5              : " << fileinfo.getVisualBasicObjectTableHashMd5() << "\n";
+	Log::info() << "SHA256           : " << fileinfo.getVisualBasicObjectTableHashSha256() << "\n";
+	Log::info() << "GUID             : " << guid << "\n";
+	Log::info() << "\n";
 
 	std::size_t cnt = 0;
 	for (std::size_t i = 0; i < nObjs; i++)
@@ -656,10 +656,10 @@ void PlainPresentation::presentVisualBasicObjects() const
 		{
 			continue;
 		}
-		std::cout << cnt << ". " << "object name: " << objName << "\n";
+		Log::info() << cnt << ". " << "object name: " << objName << "\n";
 		for (const auto &m : obj->getMethods())
 		{
-			std::cout << "    method name: " << m << "\n";
+			Log::info() << "    method name: " << m << "\n";
 		}
 		cnt++;
 	}
@@ -698,7 +698,7 @@ void PlainPresentation::presentCore() const
 
 bool PlainPresentation::present()
 {
-	std::cout << "Input file               : " << fileinfo.getPathToFile() << "\n";
+	Log::info() << "Input file               : " << fileinfo.getPathToFile() << "\n";
 	presentSimple(BasicPlainGetter(fileinfo), false);
 	presentCompiler();
 	presentLanguages();
@@ -706,12 +706,12 @@ bool PlainPresentation::present()
 	presentOverlay();
 	if(returnCode != ReturnCode::OK)
 	{
-		std::cerr << getErrorMessage(returnCode, fileinfo.getFileFormatEnum()) << "\n";
+		Log::error() << getErrorMessage(returnCode, fileinfo.getFileFormatEnum()) << "\n";
 	}
 
 	for(std::size_t i = 0, e = fileinfo.messages.size(); i < e; ++i)
 	{
-		std::cerr << fileinfo.messages[i] << "\n";
+		Log::error() << fileinfo.messages[i] << "\n";
 	}
 
 	if(verbose)
@@ -721,13 +721,13 @@ bool PlainPresentation::present()
 		errorMessage = fileinfo.getLoaderStatusMessage();
 		if(!errorMessage.empty())
 		{
-			std::cerr << "Warning: " << errorMessage << "\n";
+			Log::error() << Log::Warning << errorMessage << "\n";
 		}
 
 		errorMessage = fileinfo.getDepsListFailedToLoad();
 		if (!errorMessage.empty())
 		{
-			std::cerr << "Warning: Failed to load the dependency list (\"" << errorMessage << "\")\n";
+			Log::error() << Log::Warning << "Failed to load the dependency list (\"" << errorMessage << "\")\n";
 		}
 
 		std::string flags, title;
@@ -768,13 +768,13 @@ bool PlainPresentation::present()
 			presentTitle("Manifest");
 			if(manifest[0] != '\n')
 			{
-				std::cout << "\n";
+				Log::info() << "\n";
 			}
 			if(manifest[manifest.length() - 1] != '\n')
 			{
 				manifest += '\n';
 			}
-			std::cout << replaceNonasciiChars(manifest);
+			Log::info() << replaceNonasciiChars(manifest);
 		}
 
 		presentIterativeSimple(CertificateTablePlainGetter(fileinfo));
diff --git a/src/fileinfo/fileinfo.cpp b/src/fileinfo/fileinfo.cpp
index 5a8b52aa87..a088078804 100644
--- a/src/fileinfo/fileinfo.cpp
+++ b/src/fileinfo/fileinfo.cpp
@@ -4,13 +4,13 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <regex>
 
 #include <llvm/Support/ErrorHandling.h>
 
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/memory.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/utils/string.h"
 #include "retdec/ar-extractor/detection.h"
 #include "retdec/cpdetect/errors.h"
@@ -25,6 +25,7 @@
 #include "fileinfo/pattern_detector/pattern_detector.h"
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace retdec::ar_extractor;
 using namespace retdec::cpdetect;
 using namespace retdec::fileformat;
@@ -108,7 +109,7 @@ void fatalErrorHandler(void *user_data, const std::string& /*reason*/, bool /*ge
  */
 void printHelp()
 {
-	std::cout << "fileinfo - dumper of information about executable file\n\n"
+	Log::info() << "fileinfo - dumper of information about executable file\n\n"
 				<< "For compiler detection, program looks in the input file for YARA patterns.\n"
 				<< "According to them, it determines compiler or packer used for file creation.\n"
 				<< "Supported file formats are: " + joinStrings(getSupportedFileFormats()) + ".\n\n"
@@ -188,7 +189,7 @@ std::string getParamOrDie(std::vector<std::string> &argv, std::size_t &i)
 	}
 	else
 	{
-		std::cerr << getErrorMessage(ReturnCode::ARG) << "\n\n";
+		Log::error() << getErrorMessage(ReturnCode::ARG) << "\n\n";
 		printHelp();
 		exit(static_cast<int>(ReturnCode::ARG));
 	}
@@ -413,7 +414,7 @@ int main(int argc, char* argv[])
 	ProgParams params;
 	if(!doParams(argc, argv, params))
 	{
-		std::cerr << getErrorMessage(ReturnCode::ARG) << "\n\n";
+		Log::error() << getErrorMessage(ReturnCode::ARG) << "\n\n";
 		printHelp();
 		return static_cast<int>(ReturnCode::ARG);
 	}
@@ -517,7 +518,7 @@ int main(int argc, char* argv[])
 		auto config = ConfigPresentation(fileinfo, params.configFile);
 		if(!config.present())
 		{
-			std::cerr << "Error: loading of config failed: " << config.getErrorMessage() << "\n";
+			Log::error() << "Error: loading of config failed: " << config.getErrorMessage() << "\n";
 			res = ReturnCode::FILE_PROBLEM;
 		}
 	}
diff --git a/src/getsig/getsig.cpp b/src/getsig/getsig.cpp
index 78794857bc..fbf42782ff 100644
--- a/src/getsig/getsig.cpp
+++ b/src/getsig/getsig.cpp
@@ -5,22 +5,23 @@
  */
 
 #include <cctype>
-#include <iostream>
 #include <vector>
 
 #include "retdec/fileformat/format_factory.h"
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/string.h"
+#include "retdec/utils/io/log.h"
 
 using namespace retdec::fileformat;
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 
 /**
  * Print usage.
  */
 void printUsage()
 {
-	std::cout <<
+	Log::info() <<
 	"getsig - generator of YARA tool signatures\n\n"
 	"Program takes executable files, compares their content at given\n"
 	"offset and prints signature representing contents of all files.\n\n"
@@ -93,7 +94,7 @@ struct Options
 int printError(
 		const std::string& message)
 {
-	std::cerr << "Error: " << message << ".\n";
+	Log::error() << Log::Error << message << ".\n";
 	return 1;
 }
 
@@ -104,7 +105,7 @@ int printError(
 void printWarning(
 		const std::string& message)
 {
-	std::cerr << "Warning: " << message << ".\n";
+	Log::error() << Log::Warning << message << ".\n";
 }
 
 /**
@@ -121,7 +122,7 @@ std::string getParamOrDie(std::vector<std::string> &argv, std::size_t &i)
 	}
 	else
 	{
-		std::cerr << "Error: missing argument value.\n\n";
+		Log::error() << Log::Error << "missing argument value.\n\n";
 		printUsage();
 		exit(1);
 	}
@@ -512,7 +513,7 @@ int main(int argc, char** argv) {
 
 	// create detection rule
 	const auto rule = getYaraRule(signature, format, options);
-	std::cout << rule;
+	Log::info() << rule;
 
 	if (!options.outputFile.empty())
 	{
diff --git a/src/idr2pat/idr2pat.cpp b/src/idr2pat/idr2pat.cpp
index 50e86c2e3c..8e42cad4cb 100644
--- a/src/idr2pat/idr2pat.cpp
+++ b/src/idr2pat/idr2pat.cpp
@@ -7,18 +7,19 @@
 #include <cstdint>
 #include <fstream>
 #include <iomanip>
-#include <iostream>
 #include <istream>
 #include <map>
 #include <set>
 #include <vector>
 
 #include "retdec/utils/conversion.h"
+#include "retdec/utils/io/log.h"
 #include "yaramod/builder/yara_expression_builder.h"
 #include "yaramod/builder/yara_hex_string_builder.h"
 #include "yaramod/builder/yara_rule_builder.h"
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace yaramod;
 
 /**
@@ -217,7 +218,7 @@ void readFunction(
 	ruleBuilder.withHexString("$1", hexBuilder.get());
 	ruleBuilder.withCondition(stringRef("$1").get());
 
-	std::cout << ruleBuilder.get()->getText() << "\n";
+	Log::info() << ruleBuilder.get()->getText() << "\n";
 }
 
 /**
@@ -298,7 +299,7 @@ bool readDatabase(
  */
 int printError(const std::string &message)
 {
-	std::cerr << "Error: " << message << ".\n";
+	Log::error() << Log::Error << message << ".\n";
 	return 1;
 }
 
diff --git a/src/llvmir-emul/llvmir_emul.cpp b/src/llvmir-emul/llvmir_emul.cpp
index 0ff55faef8..558751b7b1 100644
--- a/src/llvmir-emul/llvmir_emul.cpp
+++ b/src/llvmir-emul/llvmir_emul.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/IR/CallSite.h>
 #include <llvm/IR/GetElementPtrTypeIterator.h>
 #include <llvm/IR/IRBuilder.h>
diff --git a/src/llvmir2hll/graphs/cfg/cfg_builders/non_recursive_cfg_builder.cpp b/src/llvmir2hll/graphs/cfg/cfg_builders/non_recursive_cfg_builder.cpp
index 0113e3c207..c110ddf042 100644
--- a/src/llvmir2hll/graphs/cfg/cfg_builders/non_recursive_cfg_builder.cpp
+++ b/src/llvmir2hll/graphs/cfg/cfg_builders/non_recursive_cfg_builder.cpp
@@ -28,11 +28,10 @@
 #include "retdec/llvmir2hll/support/debug.h"
 #include "retdec/llvmir2hll/support/expression_negater.h"
 #include "retdec/llvmir2hll/utils/ir.h"
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/utils/container.h"
+#include "retdec/utils/io/log.h"
 
-using namespace retdec::llvm_support;
-
+using namespace retdec::utils::io;
 using retdec::utils::clear;
 
 namespace retdec {
@@ -392,8 +391,8 @@ void NonRecursiveCFGBuilder::addEdgeFromVector(const EdgeToAdd &edge) {
 
 		// TODO This is the same problem as in the TODO below.
 		if (i == emptyStmtToNodeMap.end()) {
-			printWarningMessage("[NonRecursiveCFGBuilder] there is no node for"
-				" an edge to `", edge.succStmt, "` -> skipping this edge");
+			Log::error() << Log::Warning << "[NonRecursiveCFGBuilder] there is no node for"
+				" an edge to `" << edge.succStmt << "` -> skipping this edge" << std::endl;
 			return;
 		}
 
@@ -431,8 +430,8 @@ void NonRecursiveCFGBuilder::addEdgeFromVector(const EdgeToAdd &edge) {
 		//  - binaries-suite/arm-elf/O2/gnuarm-elf-gcc-O2--gzip
 		//
 		if (!targetNode) {
-			printWarningMessage("[NonRecursiveCFGBuilder] there is no node for"
-				" an edge to `", edge.succStmt, "` -> skipping this edge");
+			Log::error() << Log::Warning << "[NonRecursiveCFGBuilder] there is no node for"
+				" an edge to `" << edge.succStmt << "` -> skipping this edge" << std::endl;
 			return;
 		}
 
diff --git a/src/llvmir2hll/hll/hll_writers/c_hll_writer.cpp b/src/llvmir2hll/hll/hll_writers/c_hll_writer.cpp
index 57c741c106..86d7c6afee 100644
--- a/src/llvmir2hll/hll/hll_writers/c_hll_writer.cpp
+++ b/src/llvmir2hll/hll/hll_writers/c_hll_writer.cpp
@@ -100,12 +100,9 @@
 #include "retdec/llvmir2hll/support/struct_types_sorter.h"
 #include "retdec/llvmir2hll/support/types.h"
 #include "retdec/llvmir2hll/utils/ir.h"
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/utils/container.h"
 #include "retdec/utils/conversion.h"
 
-using namespace retdec::llvm_support;
-
 using retdec::utils::addToSet;
 
 namespace retdec {
diff --git a/src/llvmir2hll/llvm/llvmir2bir_converter.cpp b/src/llvmir2hll/llvm/llvmir2bir_converter.cpp
index ccb4d0891d..612956350f 100644
--- a/src/llvmir2hll/llvm/llvmir2bir_converter.cpp
+++ b/src/llvmir2hll/llvm/llvmir2bir_converter.cpp
@@ -6,7 +6,6 @@
 
 #include <llvm/IR/Module.h>
 
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/llvmir2hll/config/config.h"
 #include "retdec/llvmir2hll/ir/expression.h"
 #include "retdec/llvmir2hll/ir/function.h"
@@ -20,8 +19,9 @@
 #include "retdec/llvmir2hll/support/debug.h"
 #include "retdec/llvmir2hll/utils/ir.h"
 #include "retdec/llvmir2hll/utils/string.h"
+#include "retdec/utils/io/log.h"
 
-using namespace retdec::llvm_support;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace llvmir2hll {
@@ -148,7 +148,7 @@ ShPtr<Expression> LLVMIR2BIRConverter::convertGlobalVariableInitializer(
 */
 void LLVMIR2BIRConverter::convertAndAddGlobalVariables() {
 	if (enableDebug) {
-		printSubPhase("converting global variables");
+		Log::phase("converting global variables", Log::SubPhase);
 	}
 
 	for (auto &globVar: llvmModule->globals()) {
@@ -198,7 +198,7 @@ ShPtr<Function> LLVMIR2BIRConverter::convertFuncDeclaration(
 void LLVMIR2BIRConverter::updateFuncToDefinition(llvm::Function &func) {
 	auto name = func.getName();
 	if (enableDebug) {
-		printSubPhase("converting function " + name.str());
+		Log::phase("converting function " + name.str(), Log::SubPhase);
 	}
 
 	auto birFunc = resModule->getFuncByName(name);
diff --git a/src/llvmir2hll/llvm/llvmir2bir_converter/labels_handler.cpp b/src/llvmir2hll/llvm/llvmir2bir_converter/labels_handler.cpp
index 3cbd7132b3..05c88439c4 100644
--- a/src/llvmir2hll/llvm/llvmir2bir_converter/labels_handler.cpp
+++ b/src/llvmir2hll/llvm/llvmir2bir_converter/labels_handler.cpp
@@ -4,8 +4,6 @@
 * @copyright (c) 2017 Avast Software, licensed under the MIT license
 */
 
-// #include <iostream>
-
 #include <llvm/IR/BasicBlock.h>
 
 #include "retdec/llvmir2hll/ir/statement.h"
diff --git a/src/llvmir2hll/llvmir2hll.cpp b/src/llvmir2hll/llvmir2hll.cpp
index 056363429d..5c566d6c75 100644
--- a/src/llvmir2hll/llvmir2hll.cpp
+++ b/src/llvmir2hll/llvmir2hll.cpp
@@ -1,13 +1,13 @@
 
 #include <algorithm>
-#include <iostream>
 #include <fstream>
 #include <memory>
 
 #include "retdec/llvmir2hll/llvmir2hll.h"
-#include "retdec/llvm-support/diagnostics.h"
+#include "retdec/utils/io/log.h"
 
 using namespace llvm;
+using namespace retdec::utils::io;
 using retdec::llvmir2hll::ShPtr;
 using retdec::utils::hasItem;
 using retdec::utils::joinStrings;
@@ -50,7 +50,7 @@ std::unique_ptr<llvm::ToolOutputFile> getOutputStream(
 	);
 	if (ec)
 	{
-		errs() << ec.message() << '\n';
+		Log::error() << ec.message() << '\n';
 		return {};
 	}
 	return out;
@@ -90,21 +90,18 @@ void printErrorUnsupportedObject(
 	std::string supportedObjects(getListOfSupportedObjects<FactoryType>());
 	if (!supportedObjects.empty())
 	{
-		retdec::llvm_support::printErrorMessage(
-				"Invalid name of the ",
-				typeOfObjectsSingular,
-				" (supported names are: ",
-				supportedObjects,
-				")."
-		);
+		Log::error() << Log::Error
+			<< "Invalid name of the " << typeOfObjectsSingular
+			<< " (supported names are: " << supportedObjects << ")."
+			<< std::endl;
 	}
 	else
 	{
-		retdec::llvm_support::printErrorMessage(
-				"There are no available ",
-				typeOfObjectsPlural,
-				". Please SHIT, recompile the backend and try it again."
-		);
+		Log::error() << Log::Error
+				<< "There are no available "
+				<< typeOfObjectsPlural
+				<< ". Please SHIT, recompile the backend and try it again."
+			<< std::endl;
 	}
 }
 
@@ -152,7 +149,7 @@ void LlvmIr2Hll::getAnalysisUsage(llvm::AnalysisUsage &au) const
 
 bool LlvmIr2Hll::runOnModule(llvm::Module &m)
 {
-	llvm_support::printPhase("initialization", Debug);
+	Log::phase("initialization");
 
 	bool decompilationShouldContinue = initialize(m);
 	if (!decompilationShouldContinue)
@@ -160,7 +157,7 @@ bool LlvmIr2Hll::runOnModule(llvm::Module &m)
 		return false;
 	}
 
-	llvm_support::printPhase("conversion of LLVM IR into BIR", Debug);
+	Log::phase("conversion of LLVM IR into BIR");
 	decompilationShouldContinue = convertLLVMIRToBIR();
 	if (!decompilationShouldContinue)
 	{
@@ -169,10 +166,7 @@ bool LlvmIr2Hll::runOnModule(llvm::Module &m)
 
 	if (!globalConfig->parameters.isBackendKeepLibraryFuncs())
 	{
-		llvm_support::printPhase(
-				"removing functions from standard libraries",
-				Debug
-		);
+		Log::phase("removing functions from standard libraries");
 		removeLibraryFuncs();
 	}
 
@@ -181,94 +175,73 @@ bool LlvmIr2Hll::runOnModule(llvm::Module &m)
 	// the conversion of LLVM IR to BIR is not perfect, so it may introduce
 	// unreachable code. This causes problems later during optimizations
 	// because the code exists in BIR, but not in a CFG.
-	llvm_support::printPhase(
-			"removing code that is not reachable in a CFG",
-			Debug
-	);
+	Log::phase("removing code that is not reachable in a CFG");
 	removeCodeUnreachableInCFG();
 
-	llvm_support::printPhase("signed/unsigned types fixing", Debug);
+	Log::phase("signed/unsigned types fixing");
 	fixSignedUnsignedTypes();
 
-	llvm_support::printPhase(
-			"converting LLVM intrinsic functions to standard functions",
-			Debug
-	);
+	Log::phase("converting LLVM intrinsic functions to standard functions");
 	convertLLVMIntrinsicFunctions();
 
 	if (resModule->isDebugInfoAvailable())
 	{
-		llvm_support::printPhase("obtaining debug information", Debug);
+		Log::phase("obtaining debug information");
 		obtainDebugInfo();
 	}
 
 	if (!globalConfig->parameters.isBackendNoOpts())
 	{
-		llvm_support::printPhase(
-				"alias analysis [" + aliasAnalysis->getId() + "]",
-				Debug
-		);
+		Log::phase("alias analysis [" + aliasAnalysis->getId() + "]");
 		initAliasAnalysis();
 
-		llvm_support::printPhase(
-				"optimizations [" + getTypeOfRunOptimizations()	+ "]",
-				Debug
-		);
+		Log::phase("optimizations [" + getTypeOfRunOptimizations()	+ "]");
 		runOptimizations();
 	}
 
 	if (!globalConfig->parameters.isBackendNoVarRenaming())
 	{
-		llvm_support::printPhase(
-				"variable renaming [" + varRenamer->getId() + "]",
-				Debug
-		);
+		Log::phase("variable renaming [" + varRenamer->getId() + "]");
 		renameVariables();
 	}
 
 	if (!globalConfig->parameters.isBackendNoSymbolicNames())
 	{
-		llvm_support::printPhase(
-				"converting constants to symbolic names",
-				Debug
-		);
+		Log::phase("converting constants to symbolic names");
 		convertConstantsToSymbolicNames();
 	}
 
 	if (ValidateModule)
 	{
-		llvm_support::printPhase("module validation", Debug);
+		Log::phase("module validation");
 		validateResultingModule();
 	}
 
 	if (!FindPatterns.empty())
 	{
-		llvm_support::printPhase("finding patterns", Debug);
+		Log::phase("finding patterns");
 		findPatterns();
 	}
 
 	if (globalConfig->parameters.isBackendEmitCfg())
 	{
-		llvm_support::printPhase("emission of control-flow graphs", Debug);
+		Log::phase("emission of control-flow graphs");
 		emitCFGs();
 	}
 
 	if (globalConfig->parameters.isBackendEmitCg())
 	{
-		llvm_support::printPhase("emission of a call graph", Debug);
+		Log::phase("emission of a call graph");
 		emitCG();
 	}
 
-	llvm_support::printPhase(
-			"emission of the target code [" + hllWriter->getId() + "]",
-			Debug
-	);
+	Log::phase("emission of the target code [" + hllWriter->getId() + "]");
 	emitTargetHLLCode();
 
-	llvm_support::printPhase("finalization", Debug);
+	Log::phase("finalization");
 	finalize();
 
-	llvm_support::printPhase("cleanup", Debug);
+	Log::phase("cleanup");
 	cleanup();
 
 	return false;
@@ -293,9 +266,9 @@ bool LlvmIr2Hll::initialize(llvm::Module &m)
 	// Instantiate the requested HLL writer and make sure it exists. We need to
 	// explicitly specify template parameters because raw_pwrite_stream has
 	// a private copy constructor, so it needs to be passed by reference.
-	llvm_support::printSubPhase(
-			"creating the used HLL writer [" + TargetHLL + "]",
-			Debug
+	Log::phase(
+		"creating the used HLL writer [" + TargetHLL + "]",
+		Log::SubPhase
 	);
 
 	// Output stream into which the generated code will be emitted.
@@ -325,9 +298,9 @@ bool LlvmIr2Hll::initialize(llvm::Module &m)
 	}
 
 	// Instantiate the requested alias analysis and make sure it exists.
-	llvm_support::printSubPhase(
-			"creating the used alias analysis [" + oAliasAnalysis + "]",
-			Debug
+	Log::phase(
+		"creating the used alias analysis [" + oAliasAnalysis + "]",
+		Log::SubPhase
 	);
 	aliasAnalysis = llvmir2hll::AliasAnalysisFactory::getInstance().createObject(
 		oAliasAnalysis
@@ -342,10 +315,10 @@ bool LlvmIr2Hll::initialize(llvm::Module &m)
 
 	// Instantiate the requested obtainer of information about function
 	// calls and make sure it exists.
-	llvm_support::printSubPhase(
-			"creating the used call info obtainer ["
-			+ globalConfig->parameters.getBackendCallInfoObtainer() + "]",
-			Debug
+	Log::phase(
+		"creating the used call info obtainer ["
+		+ globalConfig->parameters.getBackendCallInfoObtainer() + "]",
+		Log::SubPhase
 	);
 	cio = llvmir2hll::CallInfoObtainerFactory::getInstance().createObject(
 		globalConfig->parameters.getBackendCallInfoObtainer()
@@ -360,10 +333,10 @@ bool LlvmIr2Hll::initialize(llvm::Module &m)
 
 	// Instantiate the requested evaluator of arithmetical expressions and make
 	// sure it exists.
-	llvm_support::printSubPhase(
-			"creating the used evaluator of arithmetical expressions [" +
-			oArithmExprEvaluator + "]",
-			Debug
+	Log::phase(
+		"creating the used evaluator of arithmetical expressions [" +
+		oArithmExprEvaluator + "]",
+		Log::SubPhase
 	);
 	auto& aeef = llvmir2hll::ArithmExprEvaluatorFactory::getInstance();
 	arithmExprEvaluator = aeef.createObject(oArithmExprEvaluator);
@@ -378,9 +351,9 @@ bool LlvmIr2Hll::initialize(llvm::Module &m)
 
 	// Instantiate the requested variable names generator and make sure it
 	// exists.
-	llvm_support::printSubPhase(
-			"creating the used variable names generator [" + oVarNameGen + "]",
-			Debug
+	Log::phase(
+		"creating the used variable names generator [" + oVarNameGen + "]",
+		Log::SubPhase
 	);
 	varNameGen = llvmir2hll::VarNameGenFactory::getInstance().createObject(
 		oVarNameGen,
@@ -395,10 +368,10 @@ bool LlvmIr2Hll::initialize(llvm::Module &m)
 	}
 
 	// Instantiate the requested variable renamer and make sure it exists.
-	llvm_support::printSubPhase(
-			"creating the used variable renamer ["
-			+ globalConfig->parameters.getBackendVarRenamer() + "]",
-			Debug
+	Log::phase(
+		"creating the used variable renamer ["
+		+ globalConfig->parameters.getBackendVarRenamer() + "]",
+		Log::SubPhase
 	);
 	varRenamer = llvmir2hll::VarRenamerFactory::getInstance().createObject(
 			globalConfig->parameters.getBackendVarRenamer(),
@@ -445,18 +418,18 @@ void LlvmIr2Hll::createSemanticsFromParameter()
 	if (oSemantics.empty() || oSemantics == "-")
 	{
 		// Do no use any semantics.
-		llvm_support::printSubPhase(
-				"creating the used semantics [none]",
-				Debug
+		Log::phase(
+			"creating the used semantics [none]",
+			Log::SubPhase
 		);
 		semantics = llvmir2hll::DefaultSemantics::create();
 	}
 	else
 	{
 		// Use the given semantics.
-		llvm_support::printSubPhase(
-				"creating the used semantics [" + oSemantics + "]",
-				Debug
+		Log::phase(
+			"creating the used semantics [" + oSemantics + "]",
+			Log::SubPhase
 		);
 		semantics = llvmir2hll::CompoundSemanticsBuilder::build(
 				split(oSemantics, ',')
@@ -474,9 +447,9 @@ void LlvmIr2Hll::createSemanticsFromLLVMIR()
 	std::string usedSemantics("libc,gcc-general,win-api");
 
 	// Use the list to create the semantics.
-	llvm_support::printSubPhase(
-			"creating the used semantics [" + usedSemantics + "]",
-			Debug
+	Log::phase(
+		"creating the used semantics [" + usedSemantics + "]",
+		Log::SubPhase
 	);
 	semantics = llvmir2hll::CompoundSemanticsBuilder::build(
 			split(usedSemantics, ',')
@@ -493,12 +466,12 @@ bool LlvmIr2Hll::loadConfig()
 	// Currently, we always use the JSON config.
 	if (globalConfig == nullptr)
 	{
-		llvm_support::printSubPhase("creating a new config", Debug);
+		Log::phase("creating a new config", Log::SubPhase);
 		config = llvmir2hll::JSONConfig::empty();
 		return true;
 	}
 
-	llvm_support::printSubPhase("loading the input config", Debug);
+	Log::phase("loading the input config", Log::SubPhase);
 	try
 	{
 		config = llvmir2hll::JSONConfig::fromString(
@@ -508,9 +481,9 @@ bool LlvmIr2Hll::loadConfig()
 	}
 	catch (const llvmir2hll::ConfigError &ex)
 	{
-		llvm_support::printErrorMessage(
-			"Loading of the config failed: " + ex.getMessage() + "."
-		);
+		Log::error() << Log::Error
+			<< "Loading of the config failed: " << ex.getMessage() << "."
+			<< std::endl;
 		return false;
 	}
 }
@@ -570,7 +543,7 @@ void LlvmIr2Hll::removeLibraryFuncs()
 		llvmir2hll::sortByName(removedFuncs);
 		for (const auto &func : removedFuncs)
 		{
-			llvm_support::printSubPhase("removing " + func->getName() + "()");
+			Log::phase("removing " + func->getName() + "()");
 		}
 	}
 }
@@ -667,7 +640,7 @@ void LlvmIr2Hll::validateResultingModule()
 	std::sort(regValidatorIDs.begin(), regValidatorIDs.end());
 	for (const auto &id : regValidatorIDs)
 	{
-		llvm_support::printSubPhase("running " + id + "Validator", Debug);
+		Log::phase("running " + id + "Validator", Log::SubPhase);
 		ShPtr<llvmir2hll::Validator> validator(
 				llvmir2hll::ValidatorFactory::getInstance().createObject(id)
 		);
@@ -738,9 +711,10 @@ void LlvmIr2Hll::emitCFGs()
 {
 	if (globalConfig->parameters.getOutputFile().empty())
 	{
-		llvm_support::printErrorMessage(
-				"Output file not set, cannot generate output CFG files."
-		);
+		Log::error() << Log::Error
+			<< "Output file not set, cannot generate output CFG files."
+			<< std::endl;
+
 		return;
 	}
 
@@ -777,9 +751,9 @@ void LlvmIr2Hll::emitCFGs()
 		std::ofstream out(fileName.c_str());
 		if (!out)
 		{
-			llvm_support::printErrorMessage(
-					"Cannot open " + fileName + " for writing."
-			);
+			Log::error() << Log::Error
+				<< "Cannot open " + fileName + " for writing."
+				<< std::endl;
 			return;
 		}
 		// Create a CFG for the current function and emit it into the opened
@@ -808,9 +782,9 @@ void LlvmIr2Hll::emitCG()
 {
 	if (globalConfig->parameters.getOutputFile().empty())
 	{
-		llvm_support::printErrorMessage(
-				"Output file not set, cannot generate output CG file."
-		);
+		Log::error() << Log::Error
+			<< "Output file not set, cannot generate output CG file."
+			<< std::endl;
 		return;
 	}
 
@@ -838,9 +812,9 @@ void LlvmIr2Hll::emitCG()
 	std::ofstream out(fileName.c_str());
 	if (!out)
 	{
-		llvm_support::printErrorMessage(
-				"Cannot open " + fileName + " for writing."
-		);
+		Log::error() << Log::Error
+			<< "Cannot open " + fileName + " for writing."
+			<< std::endl;
 		return;
 	}
 
@@ -925,8 +899,9 @@ LlvmIr2Hll::instantiatePatternFinders(
 		);
 		if (!pf && Debug)
 		{
-			llvm_support::printWarningMessage(
-				"the requested pattern finder '" + pfId + "' does not exist");
+			Log::error() << Log::Warning
+				<< "the requested pattern finder '" + pfId + "' does not exist"
+				<< std::endl;
 		}
 		else
 		{
@@ -945,7 +920,7 @@ LlvmIr2Hll::instantiatePatternFinderRunner() const
 	if (Debug)
 	{
 		return ShPtr<llvmir2hll::PatternFinderRunner>(
-			new llvmir2hll::CLIPatternFinderRunner(llvm::errs()));
+			new llvmir2hll::CLIPatternFinderRunner(Log::error()));
 	}
 	return ShPtr<llvmir2hll::PatternFinderRunner>(
 		new llvmir2hll::NoActionPatternFinderRunner()
diff --git a/src/llvmir2hll/obtainer/call_info_obtainer.cpp b/src/llvmir2hll/obtainer/call_info_obtainer.cpp
index 3df40680e2..9c9c080719 100644
--- a/src/llvmir2hll/obtainer/call_info_obtainer.cpp
+++ b/src/llvmir2hll/obtainer/call_info_obtainer.cpp
@@ -14,11 +14,10 @@
 #include "retdec/llvmir2hll/ir/variable.h"
 #include "retdec/llvmir2hll/obtainer/call_info_obtainer.h"
 #include "retdec/llvmir2hll/support/debug.h"
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/utils/container.h"
+#include "retdec/utils/io/log.h"
 
-using namespace retdec::llvm_support;
-
+using namespace retdec::utils::io;
 using retdec::utils::hasItem;
 using retdec::utils::setDifference;
 using retdec::utils::setUnion;
@@ -256,7 +255,7 @@ CallInfoObtainer::SCCWithRepresent CallInfoObtainer::findNextSCC(
 	}
 
 	// TODO Can this happen?
-	printWarningMessage("[SCCComputer] No viable SCC has been found.");
+	Log::error() << Log::Warning << "[SCCComputer] No viable SCC has been found." << std::endl;
 	FuncSet scc;
 	ShPtr<Function> func(*(remainingFuncs.begin()));
 	scc.insert(func);
diff --git a/src/llvmir2hll/obtainer/call_info_obtainers/optim_call_info_obtainer.cpp b/src/llvmir2hll/obtainer/call_info_obtainers/optim_call_info_obtainer.cpp
index 36b1983b19..b2142fae8d 100644
--- a/src/llvmir2hll/obtainer/call_info_obtainers/optim_call_info_obtainer.cpp
+++ b/src/llvmir2hll/obtainer/call_info_obtainers/optim_call_info_obtainer.cpp
@@ -13,12 +13,14 @@
 #include "retdec/llvmir2hll/ir/variable.h"
 #include "retdec/llvmir2hll/obtainer/call_info_obtainer_factory.h"
 #include "retdec/llvmir2hll/obtainer/call_info_obtainers/optim_call_info_obtainer.h"
-#include "retdec/llvmir2hll/support/debug.h"
 #include "retdec/utils/container.h"
+#include "retdec/llvmir2hll/support/debug.h"
+#include "retdec/utils/io/log.h"
 
 using retdec::utils::addToSet;
 using retdec::utils::hasItem;
 using retdec::utils::setIntersection;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace llvmir2hll {
@@ -38,33 +40,33 @@ OptimCallInfo::OptimCallInfo(ShPtr<CallExpr> call): CallInfo(call) {}
 * Only for debugging purposes.
 */
 void OptimCallInfo::debugPrint() {
-	llvm::errs() << "[OptimCallInfo] Debug info for '" << call << "':\n";
+	Log::error() << "[OptimCallInfo] Debug info for '" << call << "':\n";
 
-	llvm::errs() << "  neverReadVars:      ";
+	Log::error() << "  neverReadVars:      ";
 	dump(neverReadVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  mayBeReadVars:      ";
+	Log::error() << "  mayBeReadVars:      ";
 	dump(mayBeReadVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  alwaysReadVars:     ";
+	Log::error() << "  alwaysReadVars:     ";
 	dump(alwaysReadVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  neverModifiedVars:  ";
+	Log::error() << "  neverModifiedVars:  ";
 	dump(neverModifiedVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  mayBeModifiedVars:  ";
+	Log::error() << "  mayBeModifiedVars:  ";
 	dump(mayBeModifiedVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  alwaysModifiedVars: ";
+	Log::error() << "  alwaysModifiedVars: ";
 	dump(alwaysModifiedVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  varsWithNeverChangedValue: ";
+	Log::error() << "  varsWithNeverChangedValue: ";
 	dump(varsWithNeverChangedValue, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  varsAlwaysModifiedBeforeRead: ";
+	Log::error() << "  varsAlwaysModifiedBeforeRead: ";
 	dump(varsAlwaysModifiedBeforeRead, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "\n";
+	Log::error() << "\n";
 }
 
 bool OptimCallInfo::isNeverRead(ShPtr<Variable> var) const {
@@ -111,33 +113,33 @@ OptimFuncInfo::OptimFuncInfo(ShPtr<Function> func): FuncInfo(func) {}
 * Only for debugging purposes.
 */
 void OptimFuncInfo::debugPrint() {
-	llvm::errs() << "[OptimFuncInfo] Debug info for function '" << func->getName() << "':\n";
+	Log::error() << "[OptimFuncInfo] Debug info for function '" << func->getName() << "':\n";
 
-	llvm::errs() << "  neverReadVars:      ";
+	Log::error() << "  neverReadVars:      ";
 	dump(neverReadVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  mayBeReadVars:      ";
+	Log::error() << "  mayBeReadVars:      ";
 	dump(mayBeReadVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  alwaysReadVars:     ";
+	Log::error() << "  alwaysReadVars:     ";
 	dump(alwaysReadVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  neverModifiedVars:  ";
+	Log::error() << "  neverModifiedVars:  ";
 	dump(neverModifiedVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  mayBeModifiedVars:  ";
+	Log::error() << "  mayBeModifiedVars:  ";
 	dump(mayBeModifiedVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  alwaysModifiedVars: ";
+	Log::error() << "  alwaysModifiedVars: ";
 	dump(alwaysModifiedVars, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  varsWithNeverChangedValue: ";
+	Log::error() << "  varsWithNeverChangedValue: ";
 	dump(varsWithNeverChangedValue, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "  varsAlwaysModifiedBeforeRead: ";
+	Log::error() << "  varsAlwaysModifiedBeforeRead: ";
 	dump(varsAlwaysModifiedBeforeRead, dumpFuncGetName<ShPtr<Variable>>);
 
-	llvm::errs() << "\n";
+	Log::error() << "\n";
 }
 
 bool OptimFuncInfo::isNeverRead(ShPtr<Variable> var) const {
diff --git a/src/llvmir2hll/optimizer/optimizer_manager.cpp b/src/llvmir2hll/optimizer/optimizer_manager.cpp
index 0dce37b8dc..806fd6f02c 100644
--- a/src/llvmir2hll/optimizer/optimizer_manager.cpp
+++ b/src/llvmir2hll/optimizer/optimizer_manager.cpp
@@ -50,8 +50,9 @@
 #include "retdec/utils/container.h"
 #include "retdec/utils/string.h"
 #include "retdec/utils/system.h"
+#include "retdec/utils/io/log.h"
 
-using namespace retdec::llvm_support;
+using namespace retdec::utils::io;
 using namespace std::string_literals;
 
 using retdec::utils::hasItem;
@@ -309,7 +310,7 @@ void OptimizerManager::runOptimizerProvidedItShouldBeRun(ShPtr<Optimizer> optimi
 		try {
 			optimizer->optimize();
 		} catch (const std::bad_alloc &) {
-			printWarningMessage("out of memory; trying to recover");
+			Log::error() << Log::Warning << "out of memory; trying to recover" << std::endl;
 			std::this_thread::sleep_for(std::chrono::seconds(1));
 		}
 	} else {
@@ -328,7 +329,7 @@ void OptimizerManager::runOptimizerProvidedItShouldBeRun(ShPtr<Optimizer> optimi
 */
 void OptimizerManager::printOptimization(const std::string &optId) const {
 	if (enableDebug) {
-		printSubPhase("running "s + optId + OPT_SUFFIX);
+		Log::phase("running "s + optId + OPT_SUFFIX, Log::SubPhase);
 	}
 }
 
diff --git a/src/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.cpp b/src/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.cpp
index 98be961ddd..d4099bee1e 100644
--- a/src/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.cpp
+++ b/src/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.cpp
@@ -9,9 +9,8 @@
 #include "retdec/llvmir2hll/ir/statement.h"
 #include "retdec/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.h"
 #include "retdec/llvmir2hll/support/debug.h"
-#include "retdec/llvm-support/diagnostics.h"
 
-using namespace retdec::llvm_support;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace llvmir2hll {
@@ -28,7 +27,7 @@ const std::string PATTERN_INFO_INDENT = "      ";
 *
 * @param[out] os Output stream, into which the patterns will be emited.
 */
-CLIPatternFinderRunner::CLIPatternFinderRunner(llvm::raw_ostream &os):
+CLIPatternFinderRunner::CLIPatternFinderRunner(utils::io::Logger &os):
 	os(os) {}
 
 /**
@@ -38,7 +37,7 @@ CLIPatternFinderRunner::CLIPatternFinderRunner(llvm::raw_ostream &os):
 */
 void CLIPatternFinderRunner::doActionsBeforePatternFinderRuns(
 		ShPtr<PatternFinder> pf) {
-	printSubPhase("running " + pf->getId() + "PatternFinder", true, os);
+	os << "running " + pf->getId() + "PatternFinder";
 }
 
 /**
@@ -55,8 +54,11 @@ void CLIPatternFinderRunner::doActionsAfterPatternFinderHasRun(
 * @brief Prints information about the given pattern.
 */
 void CLIPatternFinderRunner::printPatternInfo(const ShPtr<Pattern> &p) {
-	os << PATTERN_INFO_INDENT << "Found pattern:" << "\n";
-	p->print(os, PATTERN_INFO_INDENT + "  ");
+	os << PATTERN_INFO_INDENT << "Found pattern:" << std::endl;
+	std::string str;
+	llvm::raw_string_ostream ss(str);
+	p->print(ss);
+	os << PATTERN_INFO_INDENT << "  " << str;
 }
 
 } // namespace llvmir2hll
diff --git a/src/llvmir2hll/pattern/pattern_finders/api_call_seq_pattern_finder.cpp b/src/llvmir2hll/pattern/pattern_finders/api_call_seq_pattern_finder.cpp
index 3c2e20de8c..513ceeb435 100644
--- a/src/llvmir2hll/pattern/pattern_finders/api_call_seq_pattern_finder.cpp
+++ b/src/llvmir2hll/pattern/pattern_finders/api_call_seq_pattern_finder.cpp
@@ -25,9 +25,9 @@
 #include "retdec/llvmir2hll/pattern/patterns/stmts_pattern.h"
 #include "retdec/llvmir2hll/support/debug.h"
 #include "retdec/llvmir2hll/utils/ir.h"
-#include "retdec/llvm-support/diagnostics.h"
+#include "retdec/utils/io/log.h"
 
-using namespace retdec::llvm_support;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace llvmir2hll {
@@ -57,9 +57,9 @@ void parseAndAddAPICallInfoSeqToMap(APICallInfoSeqMap &map,
 	if (seq) {
 		map.insert(std::make_pair(funcName, seq.value()));
 	} else {
-		printErrorMessage(
-			"APICallInfoSeqParser failed to parse the following pattern: ",
-			seqTextRepr);
+		Log::error() << Log::Error
+			<< "APICallInfoSeqParser failed to parse the following pattern: "
+			<< seqTextRepr;
 	}
 }
 
diff --git a/src/llvmir2hll/semantics/semantics/compound_semantics_builder.cpp b/src/llvmir2hll/semantics/semantics/compound_semantics_builder.cpp
index a6226b5e35..76658b784f 100644
--- a/src/llvmir2hll/semantics/semantics/compound_semantics_builder.cpp
+++ b/src/llvmir2hll/semantics/semantics/compound_semantics_builder.cpp
@@ -8,9 +8,9 @@
 #include "retdec/llvmir2hll/semantics/semantics/compound_semantics_builder.h"
 #include "retdec/llvmir2hll/semantics/semantics_factory.h"
 #include "retdec/llvmir2hll/support/debug.h"
-#include "retdec/llvm-support/diagnostics.h"
+#include "retdec/utils/io/log.h"
 
-using namespace retdec::llvm_support;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace llvmir2hll {
@@ -38,8 +38,9 @@ ShPtr<CompoundSemantics> CompoundSemanticsBuilder::build(
 		if (semantics) {
 			compoundSemantics->appendSemantics(semantics);
 		} else {
-			printWarningMessage("There is no registered semantics with ID \"",
-				id, "\", skipping.");
+			Log::error() << Log::Warning
+				<< "There is no registered semantics with ID \"" << id << "\", skipping."
+				<< std::endl;
 		}
 	}
 
diff --git a/src/macho-extractor/break_fat.cpp b/src/macho-extractor/break_fat.cpp
index 302569f0d2..3988b999e2 100644
--- a/src/macho-extractor/break_fat.cpp
+++ b/src/macho-extractor/break_fat.cpp
@@ -4,7 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <fstream>
 
 #include <llvm/Support/Path.h>
@@ -13,6 +12,7 @@
 
 #include "retdec/macho-extractor/break_fat.h"
 #include "retdec/utils/conversion.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/utils/string.h"
 
 using namespace llvm;
@@ -21,6 +21,7 @@ using namespace llvm::object;
 using namespace llvm::sys;
 using namespace rapidjson;
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 
 namespace {
 
@@ -337,7 +338,7 @@ bool BreakMachOUniversal::listArchitectures(
 	// Write warning when --object option is used on non-archive target.
 	if(!isStatic && withObjects)
 	{
-		std::cerr << "Warning: input file is not an archive! (--objects)\n";
+		Log::error() << Log::Warning << "input file is not an archive! (--objects)\n";
 	}
 
 	return output.good();
diff --git a/src/macho-extractortool/macho_extractor.cpp b/src/macho-extractortool/macho_extractor.cpp
index 1cd39ee2a3..32f88a4e35 100644
--- a/src/macho-extractortool/macho_extractor.cpp
+++ b/src/macho-extractortool/macho_extractor.cpp
@@ -4,7 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <set>
 
 #include <llvm/Support/FileSystem.h>
@@ -13,8 +12,10 @@
 
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/string.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/macho-extractor/break_fat.h"
 
+using namespace retdec::utils::io;
 using namespace retdec::macho_extractor;
 using namespace rapidjson;
 
@@ -24,7 +25,7 @@ enum class Mode { All, Best, Arch, Family, Index };
 
 void printUsage()
 {
-	std::cerr <<
+	Log::error() <<
 	"\nExtract objects from Mach-O Universal Binaries.\n"
 	"Usage: retdec-macho-extractor [OPTIONS] FILE\n\n"
 	"Extraction options:\n\n"
@@ -73,7 +74,7 @@ std::string getParamOrDie(
 	}
 	else
 	{
-		std::cerr << "Error: missing argument value.\n\n";
+		Log::error() << Log::Error << "missing argument value.\n\n";
 		printUsage();
 		exit(1);
 	}
@@ -98,11 +99,11 @@ void printError(
 		StringBuffer outBuffer;
 		PrettyWriter<StringBuffer> outWriter(outBuffer);
 		outDoc.Accept(outWriter);
-		std::cout << outBuffer.GetString();
+		Log::info() << outBuffer.GetString();
 	}
 	else
 	{
-		std::cerr << "Error: " << message << ".\n";
+		Log::error() << Log::Error << message << ".\n";
 	}
 }
 
@@ -117,7 +118,7 @@ int handleArguments(
 	if(args.size() < 1)
 	{
 		printUsage();
-		std::cerr << "Error: not enough arguments!\n";
+		Log::error() << Log::Error << "not enough arguments!\n";
 		return 1;
 	}
 
@@ -254,25 +255,31 @@ int handleArguments(
 	{
 		if(binary.isStaticLibrary())
 		{
-			std::cout << "Input file is a static library.\n";
+			Log::info() << "Input file is a static library.\n";
 			return 0;
 		}
 
-		std::cout << "Input file is NOT a static library.\n";
+		Log::info() << "Input file is NOT a static library.\n";
 		return 3;
 	}
 
 	// List mode
 	if(listOnly)
 	{
+		std::stringstream ss;
+		bool ret;
+
 		if(jsonOut)
 		{
-			return binary.listArchitecturesJson(std::cout, addObjects) ? 0 : 1;
+			ret = binary.listArchitecturesJson(ss, addObjects) ? 0 : 1;
 		}
 		else
 		{
-			return binary.listArchitectures(std::cout, addObjects) ? 0 : 1;
+			ret = binary.listArchitectures(ss, addObjects) ? 0 : 1;
 		}
+
+		Log::info() << ss.str();
+		return ret;
 	}
 
 	// Set default name if no name was given
diff --git a/src/pat2yara/pat2yara.cpp b/src/pat2yara/pat2yara.cpp
index 3489a15602..d6984f8fa7 100644
--- a/src/pat2yara/pat2yara.cpp
+++ b/src/pat2yara/pat2yara.cpp
@@ -5,10 +5,10 @@
  */
 
 #include <fstream>
-#include <iostream>
 #include <ostream>
 
 #include "retdec/utils/filesystem_path.h"
+#include "retdec/utils/io/log.h"
 #include "pat2yara/processing.h"
 #include "yaramod/builder/yara_file_builder.h"
 #include "yaramod/builder/yara_rule_builder.h"
@@ -19,6 +19,7 @@
  */
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace yaramod;
 
 /**
@@ -26,10 +27,9 @@ using namespace yaramod;
  *
  * @param outputStream stream to write usage to
  */
-void printUsage(
-	std::ostream &outputStream)
+void printUsage(Logger& log)
 {
-	outputStream <<
+	log <<
 	"Usage: pat2yara [-o OUTPUT_FILE] [--max-size VALUE] [--min-size VALUE]\n"
 	"  [--min-pure VALUE] [-o OUTPUT_FILE] INPUT_FILE [INPUT_FILE...]\n\n"
 	"-o --output OUTPUT_FILE\n"
@@ -61,7 +61,7 @@ void printUsage(
 int dieWithError(
 	const std::string &message)
 {
-	std::cerr << "Error: " << message << "\n";
+	Log::error() << Log::Error << message << "\n";
 	return 1;
 }
 
@@ -73,7 +73,7 @@ int dieWithError(
 void printWarning(
 	const std::string &message)
 {
-	std::cerr << "Warning: " << message << "\n";
+	Log::error() << Log::Warning << message << "\n";
 }
 
 /**
@@ -114,7 +114,7 @@ int processArguments(std::vector<std::string> &args)
 
 	for (std::size_t i = 0; i < args.size(); ++i) {
 		if (args[i] == "--help" || args[i] == "-h") {
-			printUsage(std::cout);
+			printUsage(Log::info());
 			return 0;
 		}
 		else if (args[i] == "--delphi") {
@@ -191,7 +191,7 @@ int processArguments(std::vector<std::string> &args)
 	}
 	else {
 		processFiles(fileBuilder, logBuilder, options);
-		std::cout << fileBuilder.get(false)->getText() << std::endl;
+		Log::info() << fileBuilder.get(false)->getText() << std::endl;
 	}
 
 	// Write log-file.
diff --git a/src/pdbparser/pdb_types.cpp b/src/pdbparser/pdb_types.cpp
index 54cec734c2..bf10954f3b 100644
--- a/src/pdbparser/pdb_types.cpp
+++ b/src/pdbparser/pdb_types.cpp
@@ -9,7 +9,6 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
-#include <iostream>
 #include <sstream>
 
 #include "retdec/pdbparser/pdb_types.h"
diff --git a/src/pelib/MzHeader.cpp b/src/pelib/MzHeader.cpp
index 9457efc4d0..f678fdd1ad 100644
--- a/src/pelib/MzHeader.cpp
+++ b/src/pelib/MzHeader.cpp
@@ -10,10 +10,11 @@
 * of PeLib.
 */
 
-#include <iostream>
-
+#include "retdec/utils/io/log.h"
 #include "retdec/pelib/MzHeader.h"
 
+using namespace retdec::utils::io;
+
 namespace PeLib
 {
 	/**
@@ -56,7 +57,7 @@ namespace PeLib
 		ibBuffer >> m_idhHeader.e_lfanew;
 	}
 
-	MzHeader::MzHeader(): originalOffset(0), m_ldrError() {}
+	MzHeader::MzHeader(): m_ldrError(), originalOffset(0) {}
 
 	/**
 	* Tests if the currently loaded MZ header is a valid MZ header.
@@ -164,7 +165,7 @@ namespace PeLib
 			setLoaderError(LDR_ERROR_E_LFANEW_UNALIGNED);
 
 		// The offset of PE header must not be out of file
-		if (m_idhHeader.e_lfanew > (std::uint32_t)ulFileSize)
+		if (m_idhHeader.e_lfanew > static_cast<std::uint32_t>(ulFileSize))
 			setLoaderError(LDR_ERROR_E_LFANEW_OUT_OF_FILE);
 
 		return ERROR_NONE;
@@ -186,7 +187,7 @@ namespace PeLib
 		}
 
 		std::vector<byte> vBuffer(pcBuffer, pcBuffer + uiSize);
-		for (int i=0;i<0x40;i++) std::cout << std::hex << (int)vBuffer[i] << " ";
+		for (int i=0;i<0x40;i++) Log::info() << std::hex << static_cast<int>(vBuffer[i]) << " ";
 
 		originalOffset = originalOffs;
 
diff --git a/src/pelib/ResourceDirectory.cpp b/src/pelib/ResourceDirectory.cpp
index c06f26e919..dc7fe485cf 100644
--- a/src/pelib/ResourceDirectory.cpp
+++ b/src/pelib/ResourceDirectory.cpp
@@ -382,7 +382,7 @@ namespace PeLib
 	**/
 	void ResourceLeaf::rebuild(OutputBuffer& obBuffer, unsigned int uiOffset, unsigned int uiRva, const std::string&) const
 	{
-//		std::cout << std::hex << pad << "Leaf: " << uiOffset << std::endl;
+//		Log::debug() << std::hex << pad << "Leaf: " << uiOffset << std::endl;
 
 //		obBuffer << entry.OffsetToData;
 //		obBuffer << uiOffset;
@@ -401,7 +401,7 @@ namespace PeLib
 
 			obBuffer.insert(entry.OffsetToData - uiRva + i, m_data[i]);
 		}
-//		std::cout << "LeafChild: " << std::endl;
+//		Log::debug() << "LeafChild: " << std::endl;
 	}
 
 	/**
@@ -564,20 +564,20 @@ namespace PeLib
 	**/
 	void ResourceNode::rebuild(OutputBuffer& obBuffer, unsigned int uiOffset, unsigned int uiRva, const std::string& pad) const
 	{
-/*		std::cout << std::hex << pad << uiOffset << std::endl;
+/*		Log::debug() << std::hex << pad << uiOffset << std::endl;
 
-		std::cout << std::hex << pad << "header.Characteristics: " << header.Characteristics << std::endl;
-		std::cout << std::hex << pad << "header.TimeDateStamp: " << header.TimeDateStamp << std::endl;
-		std::cout << std::hex << pad << "header.MajorVersion: "  << header.MajorVersion << std::endl;
-		std::cout << std::hex << pad << "header.MinorVersion: "  << header.MinorVersion << std::endl;
-		std::cout << std::hex << pad << "header.NumberOfNamedEntries: "  << header.NumberOfNamedEntries << std::endl;
-		std::cout << std::hex << pad << "header.NumberOfIdEntries: "  << header.NumberOfIdEntries << std::endl;
+		Log::debug() << std::hex << pad << "header.Characteristics: " << header.Characteristics << std::endl;
+		Log::debug() << std::hex << pad << "header.TimeDateStamp: " << header.TimeDateStamp << std::endl;
+		Log::debug() << std::hex << pad << "header.MajorVersion: "  << header.MajorVersion << std::endl;
+		Log::debug() << std::hex << pad << "header.MinorVersion: "  << header.MinorVersion << std::endl;
+		Log::debug() << std::hex << pad << "header.NumberOfNamedEntries: "  << header.NumberOfNamedEntries << std::endl;
+		Log::debug() << std::hex << pad << "header.NumberOfIdEntries: "  << header.NumberOfIdEntries << std::endl;
 */
 		obBuffer.insert(uiOffset, header.Characteristics);
 		obBuffer.insert(uiOffset + 4, header.TimeDateStamp);
 		obBuffer.insert(uiOffset + 8, header.MajorVersion);
 		obBuffer.insert(uiOffset + 10, header.MinorVersion);
-		//std::cout << pad << "Children: " << children.size() << std::endl;
+		//Log::debug() << pad << "Children: " << children.size() << std::endl;
 		obBuffer.insert(uiOffset + 12, header.NumberOfNamedEntries);
 		obBuffer.insert(uiOffset + 14, header.NumberOfIdEntries);
 
@@ -1044,7 +1044,7 @@ namespace PeLib
 	{
 		if (children.size())
 		{
-			std::cout << std::accumulate(children.begin(), children.end(), 0, accumulate<ResourceChild>) << std::endl;
+			Log::debug() << std::accumulate(children.begin(), children.end(), 0, accumulate<ResourceChild>) << std::endl;
 			return PELIB_IMAGE_RESOURCE_DIRECTORY::size()
 					 + std::accumulate(children.begin(), children.end(), 0, accumulate<ResourceChild>);
 		}
@@ -1128,7 +1128,7 @@ namespace PeLib
 	{
 		OutputBuffer obBuffer(vBuffer);
 		unsigned int offs = 0;
-//		std::cout << "Root: " << m_rnRoot.children.size() << std::endl;
+//		Log::debug() << "Root: " << m_rnRoot.children.size() << std::endl;
 		m_rnRoot.rebuild(obBuffer, offs, uiRva, "");
 	}
 
@@ -1490,10 +1490,10 @@ namespace PeLib
 	unsigned int ResourceDirectory::getNumberOfResources(dword dwId) const
 	{
 //		std::vector<ResourceChild>::const_iterator IterD = m_rnRoot.children.begin();
-//		std::cout << dwId << std::endl;
+//		Log::debug() << dwId << std::endl;
 //		while (IterD != m_rnRoot.children.end())
 //		{
-//			std::cout << IterD->entry.irde.Name << std::endl;
+//			Log::debug() << IterD->entry.irde.Name << std::endl;
 //			++IterD;
 //		}
 
diff --git a/src/retdec-decompiler/retdec-decompiler.cpp b/src/retdec-decompiler/retdec-decompiler.cpp
index f530292c40..719b787a72 100644
--- a/src/retdec-decompiler/retdec-decompiler.cpp
+++ b/src/retdec-decompiler/retdec-decompiler.cpp
@@ -4,7 +4,6 @@
  * @copyright (c) 2020 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <fstream>
 #include <future>
 #include <chrono>
@@ -40,7 +39,6 @@
 #include "retdec/ar-extractor/archive_wrapper.h"
 #include "retdec/ar-extractor/detection.h"
 #include "retdec/config/config.h"
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/retdec/retdec.h"
 #include "retdec/macho-extractor/break_fat.h"
 #include "retdec/unpackertool/unpackertool.h"
@@ -49,6 +47,10 @@
 #include "retdec/utils/string.h"
 #include "retdec/utils/memory.h"
 
+#include "retdec/utils/io/log.h"
+
+using namespace retdec::utils::io;
+
 const int EXIT_TIMEOUT = 137;
 const int EXIT_BAD_ALLOC = 135;
 
@@ -606,7 +608,7 @@ std::string ProgramOptions::checkFile(
 
 void ProgramOptions::printHelpAndDie()
 {
-	std::cout << programName << R"(:
+	Log::info() << programName << R"(:
 Mandatory arguments:
 	INPUT_FILE File to decompile.
 General arguments:
@@ -760,7 +762,7 @@ int decompile(retdec::config::Config& config, ProgramOptions& po)
 	);
 	if (fat.isValid())
 	{
-		retdec::llvm_support::printPhase("Mach-O extraction");
+		Log::phase("Mach-O extraction");
 
 		auto extractedFile = po.arExtractPath + "_m";
 
@@ -798,7 +800,7 @@ int decompile(retdec::config::Config& config, ProgramOptions& po)
 	//
 	if (po.arIdx || !po.arName.empty())
 	{
-		retdec::llvm_support::printPhase("Archive extraction");
+		Log::phase("Archive extraction");
 
 		bool ok = true;
 		std::string errMsg;
@@ -856,39 +858,40 @@ int decompile(retdec::config::Config& config, ProgramOptions& po)
 		);
 		if (ok && arw.isThinArchive())
 		{
-			std::cerr << "This file is an archive!" << std::endl;
-			std::cerr << "Error: File is a thin archive and cannot be decompiled." << std::endl;
+			Log::error() << "This file is an archive!" << std::endl;
+			Log::error() << "Error: File is a thin archive and cannot be decompiled." << std::endl;
 			return EXIT_FAILURE;
 		}
 		else if (ok && arw.isEmptyArchive())
 		{
-			std::cerr << "This file is an archive!" << std::endl;
-			std::cerr << "Error: The input archive is empty." << std::endl;
+			Log::error() << "This file is an archive!" << std::endl;
+			Log::error() << "Error: The input archive is empty." << std::endl;
 			return EXIT_FAILURE;
 		}
 		else if (ok)
 		{
-			std::cerr << "This file is an archive!" << std::endl;
+			Log::error() << "This file is an archive!" << std::endl;
 
 			std::string result;
 			if (arw.getPlainTextList(result, errMsg, false, true))
 			{
-				std::cerr << result << std::endl;
+				Log::error() << result << std::endl;
 			}
 			return EXIT_FAILURE;
 		}
 
 		if (!ok && retdec::ar_extractor::isArchive(config.parameters.getInputFile()))
 		{
-			std::cerr << "This file is an archive!" << std::endl;
-			std::cerr << "Error: The input archive has invalid format." << std::endl;
+			Log::error() << "This file is an archive!" << std::endl;
+			Log::error() << "Error: The input archive has invalid format." << std::endl;
 			return EXIT_FAILURE;
 		}
 	}
 
 	// Unpacking
 	//
-	retdec::llvm_support::printPhase("Unpacking");
+
+	Log::phase("Unpacking");
 	std::vector<std::string> unpackArgs;
 	unpackArgs.push_back("whatever_program_name");
 	unpackArgs.push_back(config.parameters.getInputFile());
@@ -971,7 +974,7 @@ int main(int argc, char **argv)
 	}
 	catch (const std::runtime_error& e)
 	{
-		std::cerr << "Error: " << e.what() << std::endl;
+		Log::error() << Log::Error << e.what() << std::endl;
 		return EXIT_FAILURE;
 	}
 
@@ -1002,7 +1005,7 @@ int main(int argc, char **argv)
 			else
 			{
 				thr.detach(); // we leave the thread still running
-				std::cerr << "timeout after: " << config.parameters.getTimeout()
+				Log::error() << "timeout after: " << config.parameters.getTimeout()
 						<< " seconds" << std::endl;
 				ret = EXIT_TIMEOUT;
 			}
@@ -1014,12 +1017,12 @@ int main(int argc, char **argv)
 	}
 	catch (const std::runtime_error& e)
 	{
-		std::cerr << "Error: " << e.what() << std::endl;
+		Log::error() << Log::Error << e.what() << std::endl;
 		ret = EXIT_FAILURE;
 	}
 	catch (const std::bad_alloc& e)
 	{
-		std::cerr << "catched std::bad_alloc" << std::endl;
+		Log::error() << "catched std::bad_alloc" << std::endl;
 		ret = EXIT_BAD_ALLOC;
 	}
 
diff --git a/src/retdec/retdec.cpp b/src/retdec/retdec.cpp
index 8fb91962b6..683bc85ea0 100644
--- a/src/retdec/retdec.cpp
+++ b/src/retdec/retdec.cpp
@@ -4,8 +4,6 @@
  * @copyright (c) 2019 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
-
 #include <llvm/ADT/Triple.h>
 #include <llvm/Analysis/CallGraph.h>
 #include <llvm/Analysis/CallGraphSCCPass.h>
@@ -50,9 +48,11 @@
 #include "retdec/llvmir2hll/llvmir2hll.h"
 
 #include "retdec/config/config.h"
-#include "retdec/llvm-support/diagnostics.h"
 #include "retdec/retdec/retdec.h"
 #include "retdec/utils/memory.h"
+#include "retdec/utils/io/log.h"
+
+using namespace retdec::utils::io;
 
 // extern llvm::cl::opt<bool> PrintAfterAll;
 
@@ -376,7 +376,7 @@ class ModulePassPrinter : public ModulePass
 		{
 			if (utils::startsWith(PhaseArg, "retdec"))
 			{
-				llvm_support::printPhase(PhaseName);
+				Log::phase(PhaseName);
 				LastPhase = PhaseArg;
 			}
 			else
@@ -384,12 +384,12 @@ class ModulePassPrinter : public ModulePass
 				// aggregate LLVM
 				if (LastPhase != LlvmAggregatePhaseName)
 				{
-					llvm_support::printPhase(LlvmAggregatePhaseName);
+					Log::phase(LlvmAggregatePhaseName);
 					LastPhase = LlvmAggregatePhaseName;
 				}
 
 				// print all
-				// llvm_support::printPhase(PhaseName);
+				// Log::phase(PhaseName);
 				// LastPhase = PhaseArg;
 			}
 			return false;
@@ -432,7 +432,7 @@ static inline void addPass(
 
 bool decompile(retdec::config::Config& config, std::string* outString)
 {
-	llvm_support::printPhase("Initialization");
+	Log::phase("Initialization");
 	auto& passRegistry = initializeLlvmPasses();
 
 	// limitMaximalMemoryIfRequested(params);
diff --git a/src/retdectool/retdec.cpp b/src/retdectool/retdec.cpp
index 45ffe35bf2..26b18d6f5d 100644
--- a/src/retdectool/retdec.cpp
+++ b/src/retdectool/retdec.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <cstdlib>
-#include <iostream>
 
 #include "retdec/retdec/retdec.h"
 
@@ -53,14 +52,14 @@ class ProgramOptions
 
 		void dump()
 		{
-			std::cout << std::endl;
-			std::cout << "Program Options:" << std::endl;
-			std::cout << "\t" << "input file : " << inputFile << std::endl;
+			Log::info() << std::endl;
+			Log::info() << "Program Options:" << std::endl;
+			Log::info() << "\t" << "input file : " << inputFile << std::endl;
 		}
 
 		void printHelpAndDie()
 		{
-			std::cout << _programName << ":\n"
+			Log::info() << _programName << ":\n"
 					<< "\t-i inputFile\n";
 
 			exit(EXIT_SUCCESS);
@@ -83,52 +82,52 @@ int main(int argc, char **argv)
 
 	for (auto& f : fs)
 	{
-		std::cout << std::endl;
-		std::cout << f.getName() << " @ " << f << std::endl;
+		Log::info() << std::endl;
+		Log::info() << f.getName() << " @ " << f << std::endl;
 
-		std::cout << std::endl;
-		std::cout << "\t" << "code refs (insns referencing this function):"
+		Log::info() << std::endl;
+		Log::info() << "\t" << "code refs (insns referencing this function):"
 			<< std::endl;
 		for (auto& r : f.codeReferences)
 		{
 			auto* f = fs.getRange(r);
-			std::cout << "\t\t" << r
+			Log::info() << "\t\t" << r
 				<< " ( @ " << (f ? f->getName() : "unknown") << " )"
 				<< std::endl;
 		}
 
 		for (auto& bb : f.basicBlocks)
 		{
-			std::cout << std::endl;
-			std::cout << "\t" << "bb @ " << bb << std::endl;
+			Log::info() << std::endl;
+			Log::info() << "\t" << "bb @ " << bb << std::endl;
 
-			std::cout << "\t\t" << "preds:" << std::endl;
+			Log::info() << "\t\t" << "preds:" << std::endl;
 			for (auto p : bb.preds)
 			{
-				std::cout << "\t\t\t" << p << std::endl;
+				Log::info() << "\t\t\t" << p << std::endl;
 			}
 
-			std::cout << "\t\t" << "succs:" << std::endl;
+			Log::info() << "\t\t" << "succs:" << std::endl;
 			for (auto s : bb.succs)
 			{
-				std::cout << "\t\t\t" << s << std::endl;
+				Log::info() << "\t\t\t" << s << std::endl;
 			}
 
-			std::cout << "\t\t" << "calls:" << std::endl;
+			Log::info() << "\t\t" << "calls:" << std::endl;
 			for (auto c : bb.calls)
 			{
 				auto* f = fs.getRange(c.targetAddr);
-				std::cout << "\t\t\t" << c.srcAddr << "  ->  " << c.targetAddr
+				Log::info() << "\t\t\t" << c.srcAddr << "  ->  " << c.targetAddr
 					<< " ( @ " << (f ? f->getName() : "unknown") << " )"
 					<< std::endl;
 			}
 
 			// These are not only text entries!!!
 			// There is a full Capstone representation for every instruction.
-			std::cout << "\t\t" << "instructions:" << std::endl;
+			Log::info() << "\t\t" << "instructions:" << std::endl;
 			for (auto* insn : bb.instructions)
 			{
-				std::cout << "\t\t\t" << retdec::common::Address(insn->address)
+				Log::info() << "\t\t\t" << retdec::common::Address(insn->address)
 					<< " @ " << insn->mnemonic << " " << insn->op_str
 					<< std::endl;
 			}
diff --git a/src/stacofin/stacofin.cpp b/src/stacofin/stacofin.cpp
index 6a9fa4dfa1..6df0b8cc33 100644
--- a/src/stacofin/stacofin.cpp
+++ b/src/stacofin/stacofin.cpp
@@ -4,7 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <sstream>
 #include <string>
 
diff --git a/src/stacofintool/stacofin.cpp b/src/stacofintool/stacofin.cpp
index d20a4a1803..41e380dae7 100644
--- a/src/stacofintool/stacofin.cpp
+++ b/src/stacofintool/stacofin.cpp
@@ -5,15 +5,16 @@
  */
 
 #include <iomanip>
-#include <iostream>
 #include <string>
 #include <vector>
 
 #include "retdec/utils/filesystem_path.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/stacofin/stacofin.h"
 #include "retdec/loader/image_factory.h"
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace retdec::stacofin;
 using namespace retdec::loader;
 
@@ -22,7 +23,7 @@ using namespace retdec::loader;
  */
 void printUsage()
 {
-	std::cout << "\nStatic code detection tool.\n"
+	Log::info() << "\nStatic code detection tool.\n"
 		<< "Usage: stacofin -b BINARY_FILE YARA_FILE [YARA_FILE ...]\n\n";
 }
 
@@ -35,7 +36,7 @@ void printUsage()
 int printError(
 	const std::string &errorMessage)
 {
-	std::cerr << "Error: " << errorMessage << "\n";
+	Log::error() << Log::Error << errorMessage << "\n";
 	return 1;
 }
 
@@ -69,16 +70,16 @@ void printDetectionsDebug(
 		auto& detected = p.second;
 		if (detected.getAddress() == lastAddress) {
 			for (const auto &name : detected.names) {
-				std::cout << "or " << name << "\n";
+				Log::info() << "or " << name << "\n";
 			}
 			continue;
 		}
 		lastAddress = detected.getAddress();
 
-		std::cout << "0x" << std::setfill('0') << std::setw(8) << std::hex
+		Log::info() << "0x" << std::setfill('0') << std::setw(8) << std::hex
 			<< detected.getAddress() << " " << detected.names[0] << "\n";
 		for (std::size_t i = 1; i < detected.names.size(); ++i) {
-			std::cout << "or " << detected.names[i] << "\n";
+			Log::info() << "or " << detected.names[i] << "\n";
 		}
 	}
 }
@@ -96,18 +97,18 @@ void printDetections(
 		auto& detected = p.second;
 		if (detected.getAddress() == lastAddress) {
 			for (const auto &name : detected.names) {
-				std::cout << "\t\t\t" << name << " "
+				Log::info() << "\t\t\t" << name << " "
 					<< referencesToString(detected.references) << "\n";;
 			}
 			continue;
 		}
 		lastAddress = detected.getAddress();
 
-		std::cout << "0x" << std::hex << detected.getAddress() << " \t"
+		Log::info() << "0x" << std::hex << detected.getAddress() << " \t"
 			<< std::dec << detected.size << "\t" << detected.names[0] << " "
 			<< referencesToString(detected.references) << "\n";
 		for (std::size_t i = 1; i < detected.names.size(); ++i) {
-			std::cout << "\t\t\t" << detected.names[i] << " "
+			Log::info() << "\t\t\t" << detected.names[i] << " "
 				<< referencesToString(detected.references) << "\n";;
 		}
 	}
@@ -173,7 +174,7 @@ int doActions(
 	for (auto it = coverage.begin(), e = coverage.end(); it != e; ++it) {
 		totalCoverage += it->getSize();
 	}
-	std::cout << "\nTotal code coverage is " << totalCoverage << " bytes.\n";
+	Log::info() << "\nTotal code coverage is " << totalCoverage << " bytes.\n";
 	return 0;
 }
 
diff --git a/src/unpackertool/plugin_mgr.cpp b/src/unpackertool/plugin_mgr.cpp
index 347c79759f..385fda469d 100644
--- a/src/unpackertool/plugin_mgr.cpp
+++ b/src/unpackertool/plugin_mgr.cpp
@@ -4,7 +4,6 @@
  * @copyright (c) 2017 Avast Software, licensed under the MIT license
  */
 
-#include <iostream>
 #include <regex>
 
 #include "retdec/utils/string.h"
diff --git a/src/unpackertool/unpacker.cpp b/src/unpackertool/unpacker.cpp
index 5567020a86..8b84031d85 100644
--- a/src/unpackertool/unpacker.cpp
+++ b/src/unpackertool/unpacker.cpp
@@ -5,11 +5,11 @@
  */
 
 #include <cstddef>
-#include <iostream>
 #include <memory>
 
 #include "retdec/utils/conversion.h"
 #include "retdec/utils/filesystem_path.h"
+#include "retdec/utils/io/log.h"
 #include "retdec/utils/memory.h"
 #include "retdec/cpdetect/cpdetect.h"
 #include "retdec/fileformat/fileformat.h"
@@ -19,6 +19,7 @@
 #include "plugin_mgr.h"
 
 using namespace retdec::utils;
+using namespace retdec::utils::io;
 using namespace retdec::unpacker;
 using namespace retdec::unpackertool;
 
@@ -48,17 +49,17 @@ bool detectPackers(const std::string& inputFile, std::vector<retdec::cpdetect::D
 	switch (detectFileFormat(inputFile))
 	{
 		case Format::UNDETECTABLE:
-			std::cerr << "Input file '" << inputFile << "' doesn't exist!" << std::endl;
+			Log::error() << "Input file '" << inputFile << "' doesn't exist!" << std::endl;
 			return false;
 		case Format::UNKNOWN:
-			std::cerr << "Input file '" << inputFile << "' is in unknown format!" << std::endl;
+			Log::error() << "Input file '" << inputFile << "' is in unknown format!" << std::endl;
 			return false;
 		default:
 		{
 			auto fileParser = createFileFormat(inputFile);
 			if (!fileParser)
 			{
-				std::cerr << "Error while detecting format of file '" << inputFile << "'! Please, report this." << std::endl;
+				Log::error() << "Error while detecting format of file '" << inputFile << "'! Please, report this." << std::endl;
 				return false;
 			}
 
@@ -69,7 +70,7 @@ bool detectPackers(const std::string& inputFile, std::vector<retdec::cpdetect::D
 			);
 			if (!compilerDetector)
 			{
-				std::cerr << "No compiler detector was found! Please, report this." << std::endl;
+				Log::error() << "No compiler detector was found! Please, report this." << std::endl;
 				return false;
 			}
 
@@ -93,10 +94,10 @@ ExitCode unpackFile(const std::string& inputFile, const std::string& outputFile,
 
 		if (plugins.empty())
 		{
-			std::cerr << "No matching plugins found for '" << detectedPacker.name;
+			Log::error() << "No matching plugins found for '" << detectedPacker.name;
 			if (detectedPacker.versionInfo != WILDCARD_ALL_VERSIONS)
-				std::cerr << " " << detectedPacker.versionInfo;
-			std::cerr << "'" << std::endl;
+				Log::error() << " " << detectedPacker.versionInfo;
+			Log::error() << "'" << std::endl;
 			continue;
 		}
 
@@ -121,7 +122,7 @@ ExitCode processArgs(ArgHandler& handler, char argc, char** argv)
 	// In case of failed parsing just print the help
 	if (!handler.parse(argc, argv))
 	{
-		std::cout << handler << std::endl;
+		Log::info() << handler << std::endl;
 		return EXIT_CODE_OK;
 	}
 
@@ -136,7 +137,7 @@ ExitCode processArgs(ArgHandler& handler, char argc, char** argv)
 		auto conversionSucceeded = strToNum(maxMemoryLimitStr, maxMemoryLimit);
 		if (!conversionSucceeded)
 		{
-			std::cerr << "Invalid value for --max-memory: '"
+			Log::error() << "Invalid value for --max-memory: '"
 				<< maxMemoryLimitStr << "'!\n";
 			return EXIT_CODE_MEMORY_LIMIT_ERROR;
 		}
@@ -144,7 +145,7 @@ ExitCode processArgs(ArgHandler& handler, char argc, char** argv)
 		auto limitingSucceeded = limitSystemMemory(maxMemoryLimit);
 		if (!limitingSucceeded)
 		{
-			std::cerr << "Failed to limit memory to "
+			Log::error() << "Failed to limit memory to "
 				<< maxMemoryLimitStr << " bytes!\n";
 			return EXIT_CODE_MEMORY_LIMIT_ERROR;
 		}
@@ -155,7 +156,7 @@ ExitCode processArgs(ArgHandler& handler, char argc, char** argv)
 		auto limitingSucceeded = limitSystemMemoryToHalfOfTotalSystemMemory();
 		if (!limitingSucceeded)
 		{
-			std::cerr << "Failed to limit memory to half of system RAM!\n";
+			Log::error() << "Failed to limit memory to half of system RAM!\n";
 			return EXIT_CODE_MEMORY_LIMIT_ERROR;
 		}
 	}
@@ -163,17 +164,17 @@ ExitCode processArgs(ArgHandler& handler, char argc, char** argv)
 	// -h|--help
 	if (handler["help"]->used)
 	{
-		std::cout << handler << std::endl;
+		Log::info() << handler << std::endl;
 	}
 	// -p|--plugins
 	else if (handler["plugins"]->used)
 	{
-		std::cout << "List of available plugins:" << std::endl;
+		Log::info() << "List of available plugins:" << std::endl;
 
 		for (const auto& plugin : PluginMgr::plugins)
 		{
 			const Plugin::Info* info = plugin->getInfo();
-			std::cout << info->name << " " << info->pluginVersion
+			Log::info() << info->name << " " << info->pluginVersion
 				<< " for packer '" << info->name << " " << info->packerVersion
 				<< "' (" << info->author << ")" << std::endl;
 		}
@@ -192,7 +193,7 @@ ExitCode processArgs(ArgHandler& handler, char argc, char** argv)
 	}
 	// Nothing else, just print the help
 	else
-		std::cout << handler << std::endl;
+		Log::info() << handler << std::endl;
 
 	return EXIT_CODE_OK;
 }
diff --git a/tests/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner_tests.cpp b/tests/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner_tests.cpp
index 58a5f6184e..73c100d5ea 100644
--- a/tests/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner_tests.cpp
+++ b/tests/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner_tests.cpp
@@ -14,8 +14,10 @@
 #include "retdec/llvmir2hll/pattern/pattern_finder_runners/cli_pattern_finder_runner.h"
 #include "llvmir2hll/pattern/pattern_finder_mock.h"
 #include "llvmir2hll/pattern/pattern_mock.h"
+#include "retdec/utils/io/log.h"
 
 using namespace ::testing;
+using namespace retdec::utils::io;
 
 namespace retdec {
 namespace llvmir2hll {
@@ -37,8 +39,8 @@ RunWithOnePatternFinderCallsFindPatternAndPrintOnThatFinder) {
 	NiceMock<PatternFinderMock> *pfMock(new NiceMock<PatternFinderMock>(va, cio));
 	ShPtr<PatternFinder> pf(pfMock);
 
-	std::string outputStr;
-	llvm::raw_string_ostream os(outputStr);
+	std::stringstream outputStr;
+	Logger os(outputStr);
 
 	// Expectations.
 	PatternFinder::Patterns patterns;
@@ -54,9 +56,9 @@ RunWithOnePatternFinderCallsFindPatternAndPrintOnThatFinder) {
 
 	// Test.
 	pfr->run(pf, module);
-	ASSERT_FALSE(os.str().empty());
+	ASSERT_FALSE(outputStr.str().empty());
 	// The ID of the pattern finder should be present in the output.
-	EXPECT_TRUE(os.str().find(PF_MOCK_ID) != std::string::npos);
+	EXPECT_TRUE(outputStr.str().find(PF_MOCK_ID) != std::string::npos);
 }
 
 TEST_F(CLIPatternFinderRunnerTests,
@@ -64,8 +66,8 @@ RunWithTwoPatternFindersCallsFindPatternAndPrintOnTheseFinders) {
 	INSTANTIATE_ALIAS_ANALYSIS_AND_VALUE_ANALYSIS(module);
 	INSTANTIATE_CALL_INFO_OBTAINER_MOCK();
 
-	std::string outputStr;
-	llvm::raw_string_ostream os(outputStr);
+	std::stringstream outputStr;
+	Logger os(outputStr);
 
 	// Mocks.
 	NiceMock<PatternMock> *p1Mock(new NiceMock<PatternMock>());
@@ -102,10 +104,10 @@ RunWithTwoPatternFindersCallsFindPatternAndPrintOnTheseFinders) {
 
 	// Test.
 	pfr->run(pfs, module);
-	ASSERT_FALSE(os.str().empty());
+	ASSERT_FALSE(outputStr.str().empty());
 	// The IDs of the pattern finders should be present in the output.
-	EXPECT_TRUE(os.str().find(PF1_MOCK_ID) != std::string::npos);
-	EXPECT_TRUE(os.str().find(PF2_MOCK_ID) != std::string::npos);
+	EXPECT_TRUE(outputStr.str().find(PF1_MOCK_ID) != std::string::npos);
+	EXPECT_TRUE(outputStr.str().find(PF2_MOCK_ID) != std::string::npos);
 }
 
 } // namespace tests