Initial work to add gcc support

build/Mlos.Cpp.cmake

@@ -18,11 +18,15 @@ set(CMAKE_CXX_STANDARD_REQUIRED True)
 add_compile_options(-Wall -Wextra -Wpedantic -Werror)
 add_link_options(-Wall -Wextra -Wpedantic -Werror)
 
-# The codegen output currently relies on __declspec(selectany) attributes to
-# instruct the linker to ignore extra definitions resulting from including the
+# The codegen output currently relies on asking the compiler to select one of
+# our equivalent but duplicative definitions that results from including the
 # same header in multiple places.
-# NOTE: This option is only available with clang, not gcc.
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fdeclspec")
+# For clang, make use of the original __declspec(selectany) attributes that msvc
+# uses.
+# For gcc, we use __attribute__((weak)) to achieve the same.
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fdeclspec")
+endif()
 
 # When compiling for Debug build, make sure that DEBUG is defined for the compiler.
 # This is to mimic MSVC behavior so that our #ifdefs can remain the same rather
@@ -34,40 +38,6 @@ set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DDEBUG")
 add_compile_options(-g)
 add_link_options(-g)
 
-# TODO: Search for clang compiler and set the appropriate C/CXX compiler variables.
-#if(NOT (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
-# # TODO: Add local version of clang to use?
-# find_program(CLANGCPP
-# NAMES clang++-10
-# #PATHS ENV PATH
-# )
-# if(CLANGCPP)
-# message(WARNING "Forcing CXX compiler to ${CLANGCPP}")
-# set(CMAKE_CXX_COMPILER ${CLANGPP})
-# set(CMAKE_CXX_COMPILER_ID "Clang")
-# endif()
-#endif()
-
-# For now we just abort if Clang is not the compiler selected.
-if(NOT (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
- message(SEND_ERROR
- "MLOS currently only supports clang (not '${CMAKE_CXX_COMPILER_ID}') for compilation.\n"
- "Please re-run (c)make with 'CC=clang-10 CXX=clang++-10' set.\n")
-endif()
-
-# TODO: This just finds the program, but doesn't actually enable it as a
-# target. To use clang-tidy, we will need to provide a .clang-format config
-# and probably reformat some code again.
-find_program(CLANG_TIDY NAMES clang-tidy clang-tidy-6.0)
-if(CLANG_TIDY)
- add_custom_target(
- clang-tidy
- COMMAND ${CLANG_TIDY}
- ${SOURCE_FILES}
- --
- -I ${CMAKE_SOURCE_DIR}/include)
-endif()
-
 # https://github.com/google/sanitizers/wiki/AddressSanitizer
 #
 option(ADDRESS_SANITIZER "Enable Clang AddressSanitizer" OFF)

source/Examples/SmartCache/Main.cpp

@@ -52,7 +52,7 @@ void ThrowIfFail(HRESULT hr)
 }
 
 int
-__cdecl
+MLOS_CDECL_ATTR
 main(
  _In_ int argc,
  _In_ char* argv[])

source/Examples/SmartSharedChannel/Main.cpp

@@ -72,7 +72,7 @@ void AssertFailed(
 // NOTES:
 //
 int
-__cdecl
+MLOS_CDECL_ATTR
 main(
  _In_ int argc,
  _In_ char* argv[])

source/Mlos.Core/Mlos.Core.h

@@ -74,6 +74,21 @@ constexpr int32_t INVALID_FD_VALUE = -1;
 #define MLOS_RETAIL_ASSERT(result) { if (!result) Mlos::Core::MlosPlatform::TerminateProcess(); }
 #define MLOS_UNUSED_ARG(x) (void)x
 
+#ifdef _MSC_VER
+#define MLOS_SELECTANY_LINKER_ATTR __declspec(selectany)
+#define MLOS_CDECL_ATTR __cdecl
+#elif __clang__
+// Note: this requires compiling with -fdeclspec.
+#define MLOS_SELECTANY_LINKER_ATTR __declspec(selectany)
+#define MLOS_CDECL_ATTR __cdecl
+#elif __GNUC__
+#define MLOS_SELECTANY_LINKER_ATTR __attribute__((weak))
+// cdecl is unnecessary (and emits a warning) when compiling for x86-64, which is currently the only platform we support
+#define MLOS_CDECL_ATTR /* __attribute__((cdecl))__ */
+#else
+#warning Unhandled compiler.
+#endif
+
 #include "MlosPlatform.h"
 
 #include "BytePtr.h"

source/Mlos.SettingsSystem.CodeGen/CodeWriters/CppObjectExchangeCodeWriters/CppObjectDeserializeHandlerCodeWriter.cs

@@ -49,7 +49,7 @@ public override void WriteBeginFile()
 
  // Define a global dispatch table.
  //
- WriteLine("__declspec(selectany) ::Mlos::Core::DispatchEntry DispatchTable[] = ");
+ WriteLine("MLOS_SELECTANY_LINKER_ATTR ::Mlos::Core::DispatchEntry DispatchTable[] = ");
  WriteLine("{");
 
  IndentationLevel++;

source/Mlos.SettingsSystem.CodeGen/CodeWriters/CppObjectExchangeCodeWriters/CppObjectDeserializeRuntimeCallbackCodeWriter.cs

@@ -82,7 +82,7 @@ public override void BeginVisitType(Type sourceType)
  //
  string cppTypeNameAsField = $"{sourceType.Name}_Callback";
 
- WriteLine($"__declspec(selectany) std::function<void ({cppProxyTypeFullName}&&)> {cppTypeNameAsField} = nullptr;");
+ WriteLine($"MLOS_SELECTANY_LINKER_ATTR std::function<void ({cppProxyTypeFullName}&&)> {cppTypeNameAsField} = nullptr;");
  WriteLine();
  }
 

source/Mlos.SettingsSystem.CodeGen/CodeWriters/CppObjectExchangeCodeWriters/CppObjectGetVariableDataSizeCodeWriter.cs

@@ -43,7 +43,7 @@ public override void WriteBeginFile()
  public override void WriteEndFile()
  {
  IndentationLevel--;
- WriteLine("};");
+ WriteLine("}");
  WriteLine();
  }
 

source/Mlos.SettingsSystem.CodeGen/CodeWriters/CppObjectExchangeCodeWriters/CppObjectSerializationVariableDataCodeWriter.cs

@@ -50,7 +50,7 @@ public override void WriteBeginFile()
  public override void WriteEndFile()
  {
  IndentationLevel--;
- WriteLine("};");
+ WriteLine("}");
  WriteLine();
  }
 
@@ -99,7 +99,7 @@ public override void EndVisitType(Type sourceType)
  WriteLine("return totalDataSize;");
  IndentationLevel--;
 
- WriteLine("};");
+ WriteLine("}");
  WriteLine();
  }
 

source/Mlos.SettingsSystem.CodeGen/CodeWriters/CppObjectExchangeCodeWriters/CppProxyVerifyVariableDataCodeWriter.cs

@@ -40,7 +40,7 @@ public override void WriteBeginFile()
  public override void WriteEndFile()
  {
  IndentationLevel--;
- WriteLine("};");
+ WriteLine("}");
  WriteLine();
  }
 

source/Mlos.UnitTest/Main.cpp

@@ -29,7 +29,7 @@ using ::testing::TestPartResult;
 using ::testing::UnitTest;
 
 int
-__cdecl
+MLOS_CDECL_ATTR
 main(
  _In_ int argc,
  _In_ char* argv[])

source/Mlos.UnitTest/SharedChannelTests.cpp

@@ -29,7 +29,7 @@ class TestFlatBuffer : public BytePtr
  std::array<byte, T> array = { 0 };
 };
 
-namespace
+namespace SharedChannelTests
 {
 #ifndef DEBUG
 // Verify buffer size.
@@ -212,7 +212,7 @@ TEST(SharedChannel, VerifySendingReceivingArrayStruct)
  ChannelSynchronization sync = {};
  TestSharedChannel sharedChannel(sync, buffer, 128);
 
- Mlos::UnitTest::Line line;
+ Mlos::UnitTest::Line line = {};
  line.Points[0] = { 3, 5 };
  line.Points[1] = { 7, 9 };
  line.Height = { 1.3f, 3.9f };
@@ -376,5 +376,7 @@ TEST(SharedChannel, StressSendReceive)
  result =
  resultFromReader1.get() &&
  resultFromReader2.get();
+
+ EXPECT_EQ(result, true);
 }
 }