Move codebase to requiring C++20, and fix resultant non-standard code.

Changes.txt

@@ -34,7 +34,7 @@
 
   * Added Joy2B+ controller support.
 
-  * Added auto detection for QuadTari attached controllers 
+  * Added auto detection for QuadTari attached controllers.
 
   * Enhanced Kid Vid support to play tape audio.
 
@@ -42,7 +42,7 @@
 
   * Added missing PlusROM support for E7 bankswitching.
 
-  * Enhanced movie cart (MVC) support
+  * Enhanced movie cart (MVC) support.
 
   * Accelerated emulation up to ~15% (ARM).
 
@@ -60,6 +60,9 @@
 
   * Removed 'launcherroms' option, since it was causing some issues.
 
+  * Codebase now uses C++20 features, which means a minimum of gcc-11
+    or clang-10 for Linux/Mac, and Visual Studio 2022 for Windows.
+
 -Have fun!
 
 

Makefile

@@ -51,12 +51,12 @@ CXXFLAGS+= -Wall -Wextra -Wno-unused-parameter
 CFLAGS+= -Wall -Wextra -Wno-unused-parameter
 
 ifdef HAVE_GCC
-  CXXFLAGS+= -Wno-multichar -Wunused -Woverloaded-virtual -Wnon-virtual-dtor -std=c++17
+  CXXFLAGS+= -Wno-multichar -Wunused -Woverloaded-virtual -Wnon-virtual-dtor -std=c++20
   CFLAGS+= -Wno-multichar -Wunused
 endif
 
 ifdef HAVE_CLANG
-  CXXFLAGS+= -Wno-multichar -Wunused -Woverloaded-virtual -Wnon-virtual-dtor -std=c++17
+  CXXFLAGS+= -Wno-multichar -Wunused -Woverloaded-virtual -Wnon-virtual-dtor -std=c++20
   CFLAGS+= -Wno-multichar -Wunused
 endif
 

configure

@@ -378,7 +378,7 @@ else
 	fi
 
 	for compiler in $compilers; do
-		if test_compiler "$compiler -std=c++17"; then
+		if test_compiler "$compiler -std=c++20"; then
 			CXX=$compiler
 			echo $CXX
 			break

docs/index.html

@@ -265,7 +265,7 @@
   <h2><b><a name="Features">Features</a></b></h2>
 
   <ul>
-    <li>High speed emulation using optimized C++17 code</li>
+    <li>High speed emulation using optimized C++20 code</li>
     <li>Supports high quality TIA emulation using the cycle-exact TIA core from
       <a href="https://github.com/6502ts/6502.ts">6502.ts</a> by
       Christian Speckner</li>
@@ -359,7 +359,7 @@
     <li>i386 or x86_64 class machine, with 32 or 64-bit distribution</li>
     <li>Other architectures (MIPS, PPC, PPC64, etc.) have been confirmed to work,
       but aren't as well tested as i386/x86_64</li>
-    <li>GNU g++ v/7 or Clang v/5 (with C++17 support) and the make utility are required for compiling the Stella source code</li>
+    <li>GNU g++ v/11 or Clang v/10 (with C++20 support) and the make utility are required for compiling the Stella source code</li>
   </ul>
 
   <p>

src/common/FSNodeFactory.hxx

@@ -62,8 +62,9 @@ class FSNodeFactory
           return make_unique<FSNodeZIP>(path);
         #endif
           break;
+        default:
+          return nullptr;
       }
-      return nullptr;
     }
 
   private:

src/common/FSNodeZIP.cxx

@@ -218,6 +218,7 @@ size_t FSNodeZIP::read(ByteBuffer& buffer, size_t) const
     case zip_error::NOT_A_FILE:   throw runtime_error("ZIP file contains errors/not found");
     case zip_error::NOT_READABLE: throw runtime_error("ZIP file not readable");
     case zip_error::NO_ROMS:      throw runtime_error("ZIP file doesn't contain any ROMs");
+    default: throw runtime_error("FSNodeZIP::read default case hit");
   }
 
   myZipHandler->open(_zipFile);

src/common/FpsMeter.cxx

@@ -46,32 +46,27 @@ void FpsMeter::render(uInt32 frameCount)
   }
 
   const size_t queueSize = myQueue.capacity();
-  entry first, last;
+  entry e_first, e_last;
 
-  last.frames = frameCount;
+  e_last.frames = frameCount;
-  last.timestamp = high_resolution_clock::now();
+  e_last.timestamp = high_resolution_clock::now();
 
   if (myQueue.size() < queueSize) {
-    myQueue.push_back(last);
+    myQueue.push_back(e_last);
     myFrameCount += frameCount;
 
-    first = myQueue.at(myQueueOffset);
+    e_first = myQueue.at(myQueueOffset);
   } else {
     myFrameCount = myFrameCount - myQueue.at(myQueueOffset).frames + frameCount;
-    myQueue.at(myQueueOffset) = last;
+    myQueue.at(myQueueOffset) = e_last;
 
     myQueueOffset = (myQueueOffset + 1) % queueSize;
-    first = myQueue.at(myQueueOffset);
+    e_first = myQueue.at(myQueueOffset);
   }
 
   const float myTimeInterval =
-    duration_cast<duration<float>>(last.timestamp - first.timestamp).count();
+    duration_cast<duration<float>>(e_last.timestamp - e_first.timestamp).count();
 
-  if (myTimeInterval > 0) myFps = (myFrameCount - first.frames) / myTimeInterval;
+  if (myTimeInterval > 0)
-}
+    myFps = (myFrameCount - e_first.frames) / myTimeInterval;
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-float FpsMeter::fps() const
-{
-  return myFps;
 }

src/common/FpsMeter.hxx

@@ -32,7 +32,7 @@ class FpsMeter
 
     void render(uInt32 frameCount);
 
-    float fps() const;
+    float fps() const { return myFps; }
 
   private:
 

src/common/LinkedObjectPool.hxx

@@ -59,7 +59,7 @@ class LinkedObjectPool
     /*
       Create a pool of size CAPACITY; the active list starts out empty.
     */
-    LinkedObjectPool<T, CAPACITY>() { resize(CAPACITY); }
+    LinkedObjectPool() { resize(CAPACITY); }
 
     /**
       Return node data that the 'current' iterator points to.

src/common/MouseControl.cxx

@@ -96,6 +96,8 @@ MouseControl::MouseControl(Console& console, string_view mode)
           id = 1;
           msg << "Right MindLink";
           break;
+        default:
+          break;  // Not supposed to get here
       }
     };
 

src/common/SDL_lib.hxx

@@ -31,6 +31,7 @@
   #pragma clang diagnostic ignored "-Wimplicit-fallthrough"
   #pragma clang diagnostic ignored "-Wreserved-id-macro"
   #pragma clang diagnostic ignored "-Wold-style-cast"
+  #pragma clang diagnostic ignored "-Wswitch-default"
   #include <SDL.h>
   #pragma clang diagnostic pop
 #elif defined(BSPF_WINDOWS)

src/common/SoundSDL2.cxx

@@ -283,6 +283,8 @@ string SoundSDL2::about() const
     case AudioSettings::Preset::ultraQualityMinimalLag:
       buf << "Ultra quality, minimal lag\n";
       break;
+    default:
+      break;  // Not supposed to get here
   }
   buf << "    Fragment size: " << static_cast<uInt32>(myHardwareSpec.samples)
       << " bytes\n"
@@ -300,6 +302,8 @@ string SoundSDL2::about() const
     case AudioSettings::ResamplingQuality::lanczos_3:
       buf << "Quality 3, Lanczos (a = 3)\n";
       break;
+    default:
+      break;  // Not supposed to get here
   }
   buf << "    Headroom:      " << std::fixed << std::setprecision(1)
       << (0.5 * myAudioSettings.headroom()) << " frames\n"

src/common/Stack.hxx

@@ -37,7 +37,7 @@ class FixedStack
   public:
     using StackFunction = std::function<void(T&)>;
 
-    FixedStack<T, CAPACITY>() = default;
+    FixedStack() = default;
 
     bool empty() const { return _size == 0; }
     bool full() const  { return _size >= CAPACITY; }

src/common/VideoModeHandler.cxx

@@ -139,6 +139,8 @@ VideoModeHandler::Mode::Mode(uInt32 iw, uInt32 ih, uInt32 sw, uInt32 sh,
         iw = std::min(static_cast<uInt32>(iw * zoomLevel), screenS.w) * overscan;
         ih = std::min(static_cast<uInt32>(ih * zoomLevel), screenS.h) * overscan;
         break;
+      default:
+        break;  // Not supposed to get here
     }
   }
   else
@@ -157,6 +159,9 @@ VideoModeHandler::Mode::Mode(uInt32 iw, uInt32 ih, uInt32 sw, uInt32 sh,
 
       case Stretch::None: // UI Mode
         break;  // Do not change image or screen rects whatsoever
+
+      default:
+        break;  // Not supposed to get here
     }
   }
 

src/common/tv_filters/AtariNTSC.cxx

@@ -107,7 +107,7 @@ void AtariNTSC::render(const uInt8* atari_in, const uInt32 in_width,
   // Spawn the threads...
   for(uInt32 i = 0; i < myWorkerThreads; ++i)
   {
-    myThreads[i] = std::thread([=] // NOLINT (cppcoreguidelines-misleading-capture-default-by-value
+    myThreads[i] = std::thread([=, this]
     {
       rgb_in == nullptr ?
         renderThread(atari_in, in_width, in_height, myTotalThreads,

src/debugger/CartDebug.cxx

@@ -741,6 +741,9 @@ bool CartDebug::getLabel(ostream& buf, uInt16 addr, bool isRead,
       }
       break;
     }
+
+    default:
+      break;  // Not supposed to get here
   }
 
   switch(places)

src/debugger/DebuggerParser.cxx

@@ -383,6 +383,8 @@ bool DebuggerParser::getArgs(string_view command, string& verb)
           curArg += c;
         }
         break;
+      default:
+        break;  // Not supposed to get here
     }  // switch(state)
   }
   while(i < length);
@@ -505,6 +507,9 @@ bool DebuggerParser::validateArgs(int cmd)
 
       case Parameters::ARG_END_ARGS:
         break;
+
+      default:
+        break;  // Not supposed to get here
     }
     ++curCount;
     ++p;
@@ -2645,6 +2650,8 @@ void DebuggerParser::executeTrapRW(uInt32 addr, bool read, bool write, bool add)
       }
       break;
     }
+    default:
+      break;  // Not supposed to get here
   }
 }
 

src/debugger/TIADebug.cxx

@@ -505,8 +505,10 @@ bool TIADebug::collision(CollisionBit id, bool toggle) const
       if(toggle)
         myTIA.toggleCollM0M1();
       return myTIA.collCXPPMM() & 0x40;
+
+    default:
+      return false;  // Not supposed to get here
   }
-  return false;  // make compiler happy
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

src/debugger/yacc/YaccParser.cxx

@@ -399,6 +399,9 @@ int yylex() {
           return yylval.val;
         }
         break;
+
+      default:
+        break;  // Not supposed to get here
     }
   }
 

src/emucore/CartMVC.cxx

@@ -1516,6 +1516,9 @@ bool MovieCart::process(uInt16 address)
     case TitleState::Stream:
       runStateMachine();
       break;
+
+    default:
+      break;  // Not supposed to get here
   }
 
   return a12;

src/emucore/FBSurface.cxx

@@ -293,6 +293,9 @@ void FBSurface::frameRect(uInt32 x, uInt32 y, uInt32 w, uInt32 h,
         vLine(x + w - 1, i, i, color);
       }
       break;
+
+    default:
+      break;  // Not supposed to get here
   }
 }
 

src/emucore/FSNode.hxx

@@ -104,7 +104,7 @@ class FSNode
 
     /**
      * Append the given path to the node, adding a directory separator
-     * when necessary.  Modelled on the C++17 fs::path API.
+     * when necessary.
      */
     FSNode& operator/=(string_view path);
 

src/emucore/FrameBuffer.cxx

@@ -890,6 +890,9 @@ inline bool FrameBuffer::drawMessage()
         myMsg.x = imageRect().w() - dst.w() - 5;
         myMsg.y = imageRect().h() - dst.h() - 5;
         break;
+
+      default:
+        break;  // Not supposed to get here
     }
 
     myMsg.surface->setDstPos(myMsg.x + imageRect().x(), myMsg.y + imageRect().y());

src/emucore/PlusROM.cxx

@@ -433,7 +433,7 @@ void PlusROM::send()
     // as the thread is running. Thus, the request can only be destructed once
     // the thread has finished, and we can safely evict it from the deque at
     // any time.
-    std::thread thread([=]() // NOLINT (cppcoreguidelines-misleading-capture-default-by-value)
+    std::thread thread([=, this]()
     {
       request->execute();
       switch(request->getState())

src/emucore/TIASurface.cxx

@@ -482,6 +482,8 @@ string TIASurface::effectsInfo() const
     case Filter::BlarggPhosphor:
       buf << myNTSCFilter.getPreset() << ", phosphor=" << myPBlend;
       break;
+    default:
+      break;  // Not supposed to get here
   }
   if(attr.blendalpha)
     buf << ", scanlines=" << attr.blendalpha
@@ -585,6 +587,9 @@ void TIASurface::render(bool shade)
       myNTSCFilter.render(myTIA->frameBuffer(), width, height, out, outPitch << 2, myRGBFramebuffer.data());
       break;
     }
+
+    default:
+      break;  // Not supposed to get here
   }
 
   // Draw TIA image
@@ -624,7 +629,7 @@ void TIASurface::renderForSnapshot()
   myTiaSurface->basePtr(outPtr, outPitch);
 
   mySaveSnapFlag = false;
-  switch (myFilter)
+  switch(myFilter)
   {
     // For non-phosphor modes, render the frame again
     case Filter::Normal:
@@ -650,11 +655,16 @@ void TIASurface::renderForSnapshot()
     }
 
     case Filter::BlarggPhosphor:
+    {
       uInt32 bufofs = 0;
       for(uInt32 y = height; y; --y)
         for(uInt32 x = outPitch; x; --x)
           outPtr[pos++] = averageBuffers(bufofs++);
       break;
+    }
+
+    default:
+      break;  // Not supposed to get here
   }
 
   if(myPhosphorHandler.phosphorEnabled())

src/emucore/tia/Playfield.cxx

@@ -224,6 +224,9 @@ void Playfield::applyColors()
           myColorRight = myColorP1 &= 0xfe;
         }
         break;
+
+      default:
+        break;  // Not supposed to get here
     }
   }
 }

src/emucore/tia/TIA.cxx

@@ -436,6 +436,9 @@ void TIA::bindToControllers()
         case Controller::AnalogPin::Nine:
           updateAnalogReadout(0);
           break;
+
+        default:
+          break;  // Not supposed to get here
       }
     }
   );
@@ -452,6 +455,9 @@ void TIA::bindToControllers()
         case Controller::AnalogPin::Nine:
           updateAnalogReadout(2);
           break;
+
+        default:
+          break;  // Not supposed to get here
       }
     }
   );
@@ -1797,6 +1803,9 @@ FORCE_INLINE void TIA::renderPixel(uInt32 x, uInt32 y)
         else if (myBall.isOn())       color = myBall.getColor();
         else                          color = myBackground.getColor();
         break;
+
+      default:
+        break;  // Not supposed to get here
     }
   }
 

src/emucore/tia/frame-manager/FrameLayoutDetector.cxx

@@ -239,7 +239,7 @@ void FrameLayoutDetector::finalizeFrame()
   // 1.0 (>=312) and added to PAL and (inverted) NTSC sums.
   constexpr double ODD_PENALTY = 0.5; // guessed value :)
   const double palFrame = BSPF::clamp(((myCurrentFrameFinalLines % 2) ? ODD_PENALTY : 1.0)
-    * (static_cast<double>(myCurrentFrameFinalLines) - frameLinesNTSC)
+    * static_cast<double>(myCurrentFrameFinalLines - frameLinesNTSC)
     / static_cast<double>(frameLinesPAL - frameLinesNTSC), 0.0, 1.0);
   myPalFrameSum += palFrame;
   myNtscFrameSum += 1.0 - palFrame;

src/gui/BrowserDialog.cxx

@@ -265,6 +265,9 @@ void BrowserDialog::show(string_view startpath,
       _selected->setEnabled(false);
       _okWidget->setLabel("OK");
       break;
+
+    default:
+      break;  // Not supposed to get here
   }
 
   // Set start path

src/gui/DialogContainer.cxx

@@ -320,6 +320,7 @@ void DialogContainer::handleMouseButtonEvent(MouseButton b, bool pressed,
       break;
 
     case MouseButton::NONE:  // should never get here
+    default:
       break;
   }
 }

src/gui/Widget.cxx

@@ -968,6 +968,8 @@ void CheckboxWidget::setFill(FillType type)
       _img = checked_img_circle.data();
       _drawBox = false;
       break;
+    default:
+      break;  // Not supposed to get here
   }
   setDirty();
 }

src/os/libretro/Makefile

@@ -46,7 +46,7 @@ TARGET_NAME = stella
 
 
 ifeq (,$(findstring msvc,$(platform)))
-   CXXFLAGS += -std=c++17 -fno-rtti
+   CXXFLAGS += -std=c++20 -fno-rtti
    LIBS := -lm
 else
    LIBS :=
@@ -305,8 +305,8 @@ else ifneq (,$(filter $(platform), ngc wii wiiu))
 else ifeq ($(platform), emscripten)
    TARGET := $(TARGET_NAME)_libretro_$(platform).bc
    STATIC_LINKING = 1
-   CXXFLAGS += $(PTHREAD_FLAGS) -std=c++17
+   CXXFLAGS += $(PTHREAD_FLAGS) -std=c++20
-   LDFLAGS += $(PTHREAD_FLAGS) -std=c++17
+   LDFLAGS += $(PTHREAD_FLAGS) -std=c++20
 
 # Genode
 else ifeq ($(platform), genode)
@@ -370,7 +370,7 @@ else ifneq (,$(findstring windows_msvc2017,$(platform)))
    endif
 
    # Specific to this core
-   MSVC2017CompileFlags += -D__WIN32__ /std:c++17
+   MSVC2017CompileFlags += -D__WIN32__ /std:c++20
 
    CXX = cl.exe
    CXXFLAGS += $(MSVC2017CompileFlags)

src/os/libretro/jni/Android.mk

@@ -14,6 +14,6 @@ endif
 include $(CLEAR_VARS)
 LOCAL_MODULE    := retro
 LOCAL_SRC_FILES := $(SOURCES_CXX) $(SOURCES_C)
-LOCAL_CXXFLAGS  := $(COREFLAGS) -std=c++17
+LOCAL_CXXFLAGS  := $(COREFLAGS) -std=c++20
 LOCAL_LDFLAGS   := -Wl,-version-script=$(CORE_DIR)/os/libretro/link.T
 include $(BUILD_SHARED_LIBRARY)

src/os/macos/stella.xcodeproj/project.pbxproj

@@ -3791,7 +3791,7 @@
 				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_RAND = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_STRCPY = YES;
-				CLANG_CXX_LANGUAGE_STANDARD = "c++17";
+				CLANG_CXX_LANGUAGE_STANDARD = "c++20";
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_WARN_ASSIGN_ENUM = YES;
 				CLANG_WARN_ATOMIC_IMPLICIT_SEQ_CST = YES;
@@ -3869,7 +3869,7 @@
 				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_RAND = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_STRCPY = YES;
-				CLANG_CXX_LANGUAGE_STANDARD = "c++17";
+				CLANG_CXX_LANGUAGE_STANDARD = "c++20";
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_WARN_ASSIGN_ENUM = YES;
 				CLANG_WARN_ATOMIC_IMPLICIT_SEQ_CST = YES;

src/os/windows/Stella.vcxproj

@@ -593,7 +593,7 @@
       <WarningLevel>Level4</WarningLevel>
       <DebugInformationFormat>None</DebugInformationFormat>
       <ObjectFileName>$(IntDir)obj\\windows\%(RelativeDir)</ObjectFileName>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <DisableSpecificWarnings>4100;4127;4146;4244;26400;26409;26410;26415;26429;26438;26440;26446;26451;26455;26459;26467;26472;26481;26482;26485;26492;%(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAs>CompileAsCpp</CompileAs>