macOS: Switch to C++17 (like the other platforms) (surge-synthesizer#…

…5124)

Library support is spotty on our current deployment target 10.11 "El
Capitan", but a consistent language level across platforms does make
life easier for devs, especially those who aren't on Mac. C++17 also
fixes under-aligned allocations on ARM Macs, potentially improving
performance.

To keep us pre-Mojave compatible, this implements aligned operators
new/delete in a new library "surge-platform" that will also become home
for other platform-specific code currently lurking between #ifdefs.

CMakeLists.txt

@@ -25,11 +25,7 @@ message(STATUS "Targeting ${SURGE_BITNESS} bit configuration")
 # }}}
 # Global compiler/linker settings {{{
 set(CMAKE_CXX_EXTENSIONS OFF)
-if(APPLE)
-  set(CMAKE_CXX_STANDARD 14)
-else()
-  set(CMAKE_CXX_STANDARD 17)
-endif()
+set(CMAKE_CXX_STANDARD 17)
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "Clang|GNU")
   # Any Clang or any GCC
@@ -91,6 +87,7 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "Clang|GNU")
     if(CMAKE_CXX_COMPILER_ID MATCHES "^AppleClang$")
       # Apple Clang only
       add_compile_options(
+        -faligned-allocation
         -fasm-blocks
       )
     endif()

libs/catch2/CMakeLists.txt

@@ -4,3 +4,4 @@ add_library(${PROJECT_NAME} INTERFACE)
 target_sources(${PROJECT_NAME} INTERFACE include/${PROJECT_NAME}/catch2.hpp)
 add_library(surge::${PROJECT_NAME} ALIAS ${PROJECT_NAME})
 target_include_directories(${PROJECT_NAME} INTERFACE include)
+target_compile_definitions(${PROJECT_NAME} INTERFACE $<$<BOOL:${APPLE}>:CATCH_CONFIG_NO_CPP17_UNCAUGHT_EXCEPTIONS>)

src/CMakeLists.txt

@@ -97,6 +97,7 @@ endif()
 message(STATUS "Building Surge JUCE as ${SURGE_JUCE_FORMATS}")
 
 add_subdirectory(common)
+add_subdirectory(platform)
 
 if(SURGE_BUILD_TESTRUNNER)
   add_subdirectory(surge-testrunner)

src/common/CMakeLists.txt

@@ -320,6 +320,7 @@ target_link_libraries(${PROJECT_NAME} PUBLIC
   surge::tinyxml
   surge-common-binary
   tuning-library
+  PRIVATE surge-platform
 )
 target_include_directories(${PROJECT_NAME} PUBLIC
   ${CMAKE_CURRENT_SOURCE_DIR}

src/common/SurgeStorage.cpp

@@ -56,10 +56,6 @@
 #include "MSEGModulationHelper.h"
 // FIXME
 
-#if __cplusplus < 201703L
-constexpr float MSEGStorage::minimumDuration;
-#endif
-
 float sinctable alignas(16)[(FIRipol_M + 1) * FIRipol_N * 2];
 float sinctable1X alignas(16)[(FIRipol_M + 1) * FIRipol_N];
 short sinctableI16 alignas(16)[(FIRipol_M + 1) * FIRipolI16_N];

src/common/dsp/vembertech/basic_dsp.h

@@ -3,11 +3,7 @@
 
 template <typename T> inline T limit_range(const T &x, const T &low, const T &high)
 {
-#if __cplusplus > 201402L
     return std::clamp(x, low, high);
-#else
-    return std::min(std::max(x, low), high);
-#endif
 }
 
 template <typename T> inline T limit01(const T &x) { return limit_range(x, (T)0, (T)1); }

src/platform/CMakeLists.txt

@@ -0,0 +1,10 @@
+# vi:set sw=2 et:
+project(surge-platform)
+
+if(APPLE)
+  add_library(${PROJECT_NAME})
+  target_sources(${PROJECT_NAME} PRIVATE macos/cpp17-aligned-new.cpp)
+else()
+  # no sources yet on other platforms
+  add_library(${PROJECT_NAME} INTERFACE)
+endif()

src/platform/macos/cpp17-aligned-new.cpp

@@ -0,0 +1,35 @@
+/*
+** Surge Synthesizer is Free and Open Source Software
+**
+** Surge is made available under the Gnu General Public License, v3.0
+** https://www.gnu.org/licenses/gpl-3.0.en.html
+**
+** Copyright 2004-2021 by various individuals as described by the Git transaction log
+**
+** All source at: https://github.com/surge-synthesizer/surge.git
+**
+** Surge was a commercial product from 2004-2018, with Copyright and ownership
+** in that period held by Claes Johanson at Vember Audio. Claes made Surge
+** open source in September 2018.
+*/
+
+#include <cstdlib>
+#include <new>
+
+/*
+ * Since C++17, new'ing objects respects their alignas() requirements. If the required alignment
+ * exceeds that provided by operator new, alignment-aware overloads are called instead. On macOS,
+ * these are only present on 10.14 "Mojave" and up, so we ship our own implementation.
+ *
+ * Relevant discussion in GitHub issues #171, #188, #3589
+ */
+
+void *operator new(std::size_t size, std::align_val_t align)
+{
+    void *result;
+    if (posix_memalign(&result, std::size_t(align), size))
+        throw std::bad_alloc{};
+    return result;
+}
+
+void operator delete(void *p, std::align_val_t) noexcept { free(p); }