[c++] Move ABI implementation to own module, add option to use exceptions and RTTI

examples/stm32f469_discovery/exceptions_rtti/main.cpp

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2020, Niklas Hauser
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/board.hpp>
+#include <typeinfo>
+
+using namespace Board;
+
+// ----------------------------------------------------------------------------
+int
+main()
+{
+	Board::initialize();
+	LedD13::setOutput(modm::Gpio::Low);
+	uint32_t counter(0);
+
+	MODM_LOG_INFO << "TypeId for LedD13: " << typeid(LedD13).name() << modm::endl;
+
+	while (true)
+	{
+		LedBlue::toggle();
+		modm::delayMilliseconds(500);
+
+		try {
+			throw counter++;
+		}
+		catch (uint32_t code) {
+			MODM_LOG_ERROR << "Caught exception #" << code << modm::endl;
+		}
+	}
+
+	return 0;
+}

examples/stm32f469_discovery/exceptions_rtti/project.xml

@@ -0,0 +1,12 @@
+<library>
+  <extends>modm:disco-f469ni</extends>
+  <options>
+    <option name="modm:build:build.path">../../../build/stm32f469_discovery/exceptions_rtti</option>
+    <option name="modm:stdc++:exceptions">true</option>
+    <option name="modm:stdc++:rtti">true</option>
+  </options>
+  <modules>
+    <module>modm:platform:gpio</module>
+    <module>modm:build:scons</module>
+  </modules>
+</library>

ext/gcc/cxxabi.cpp.in

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2009-2011, Fabian Greif
+ * Copyright (c) 2010, Martin Rosekeit
+ * Copyright (c) 2012, Sascha Schade
+ * Copyright (c) 2012-2014, 2020, Niklas Hauser
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/architecture/interface/assert.hpp>
+
+extern "C"
+{
+
+/**
+ * \brief Pure-virtual workaround.
+ *
+ * The libc does not support a default implementation for handling
+ * possible pure-virtual calls. This is a short and empty workaround for this.
+ */
+void
+__cxa_pure_virtual()
+{
+	modm_assert_debug(0, "cxa", "virtual", "pure");
+}
+
+%% if target.platform in ["avr"]
+int __cxa_atexit(void (*)(void *), void *, void *)
+%% else
+// ARM EABI specifies __aeabi_atexit instead of __cxa_atexit
+int __aeabi_atexit(void (*)(void *), void *, void *)
+%% endif
+{
+	return 0;
+}
+
+void* __dso_handle = (void*) &__dso_handle;
+
+}

ext/gcc/libcabi_cortex.cpp

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2020, Niklas Hauser
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/architecture/interface/assert.hpp>
+
+// ------------------------------------------------------------------------
+extern "C"
+{
+
+extern void _exit(int);
+void _exit(int status)
+{
+	modm_assert(false, "libc", "libc", "exit", status);
+}
+
+}

ext/gcc/module.lb

@@ -16,29 +16,113 @@
 def init(module):
     module.name = ":stdc++"
     module.description = """\
-# C++ Standard Library
+# C++ Standard Environment
 
-A partial port of GCC 8 libstdc++ for AVR.
+Refines the C++ language to make it easier to use on embedded targets.
+Depending on the module options, the compiler options are appended with either:
+
+- `-fno-exceptions`: no C++ exceptions.
+- `-fno-rtti`: no C++ run-time type information.
+
+or:
+
+- `-fexceptions`: with C++ exceptions.
+- `-frtti`: with C++ run-time type information.
+
+## AVR
+
+A partial port of GCC 8 libstdc++ is provided:
 See https://github.com/modm-io/avr-libstdcpp.
+
+## ARM Cortex-M
+
+Additional compiler options:
+
+- `-fno-threadsafe-statics`: No thread-safe static initialization provided.
+- `--specs=nano.specs`: use Newlib Nano (when not using exceptions).
+- `--specs=nosys.specs`: No additional C library features are implemented.
 """
 
 
 def prepare(module, options):
-    if options[":target"].identifier.platform != "avr":
+    is_avr = options[":target"].identifier.platform == "avr"
+    is_cortex_m = options[":target"].has_driver("core:cortex-m*")
+    if not (is_avr or is_cortex_m):
         return False
 
-    module.add_option(
-        BooleanOption(
-            name="use_modm_assert",
-            description="Assert on error in stdlib. Set to False to save flash.",
-            default=True))
+    if is_avr:
+        module.add_option(
+            BooleanOption(
+                name="use_modm_assert", default=True,
+                description="Assert on exception in stdlib. Set to False to save flash."))
+
+    elif is_cortex_m:
+        module.add_option(
+            BooleanOption(
+                name="exceptions", default=False,
+                description=descr_exceptions))
+        module.add_option(
+            BooleanOption(
+                name="rtti", default=False,
+                description=descr_rtti))
+
+    module.depends(":architecture:assert",
+                   ":architecture:memory")
 
     return True
 
 
 def build(env):
-    env.collect(":build:path.include", "modm/ext/gcc/libstdc++/include")
-
+    is_avr = env[":target"].identifier.platform == "avr"
+    is_cortex_m = env[":target"].has_driver("core:cortex-m*")
+    env.substitutions = {"target": env[":target"].identifier}
     env.outbasepath = "modm/ext/gcc"
-    env.copy(".", ignore=env.ignore_files("*.lb", "*.md", "*.in", "examples"))
-    env.template("assert.cpp.in", "assert.cpp")
+    env.template("cxxabi.cpp.in")
+
+    if is_avr:
+        env.collect(":build:path.include", "modm/ext/gcc/libstdc++/include")
+        env.copy("libstdc++", ignore=env.ignore_files("*.lb", "*.md", "*.in", "examples"))
+        env.template("assert.cpp.in", "assert.cpp")
+
+        env.copy("newdelete_avr.cpp", "newdelete.cpp")
+
+    elif is_cortex_m:
+        env.copy("libcabi_cortex.cpp", "libcabi.cpp")
+        env.copy("newdelete_cortex.cpp", "newdelete.cpp")
+
+    # Compilation flags
+    env.collect(":build:cxxflags", "-fuse-cxa-atexit", "-fno-threadsafe-statics")
+    if env.get("exceptions", False):
+        env.collect(":build:cxxflags", "-fexceptions", "-funwind-tables")
+    else:
+        env.collect(":build:cxxflags", "-fno-exceptions", "-fno-unwind-tables")
+    if env.get("rtti", False):
+        env.collect(":build:cxxflags", "-frtti")
+    else:
+        env.collect(":build:cxxflags", "-fno-rtti")
+
+    if is_cortex_m:
+        env.collect(":build:linkflags", "--specs=nosys.specs")
+        if not env.get("exceptions", False):
+            # Newlib Nano does not support C++ exceptions at all
+            env.collect(":build:linkflags", "--specs=nano.specs")
+
+# ============================ Option Descriptions ============================
+
+descr_exceptions = """# C++ Exceptions
+
+Enables the full use of C++ exception handling.
+
+!!! warning "Check your code size"
+    The inclusion of the stack unwind tables will increase your code size quite
+    a bit. Check whether your target has enough memory for this!
+"""
+
+descr_rtti = """# C++ Runtime Type Information
+
+Enables the full use of C++ runtime type information.
+
+!!! warning "Check your code size"
+    The inclusion of the RTTI information will increase your code size quite a
+    bit. Check whether your target has enough memory for this!
+"""

src/modm/platform/core/avr/newdelete.cpp → ext/gcc/newdelete_avr.cpp

@@ -12,10 +12,10 @@
  */
 // ----------------------------------------------------------------------------
 
-#include "ram.hpp"
 #include <new>
 #include <modm/architecture/interface/memory.hpp>
 #include <modm/architecture/interface/assert.hpp>
+#include <modm/platform/core/ram.hpp>
 
 void *
 operator new(size_t size)

src/modm/platform/core/cortex/cxxabi.cpp → ext/gcc/newdelete_cortex.cpp

@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2009-2010, Martin Rosekeit
  * Copyright (c) 2009-2011, Fabian Greif
- * Copyright (c) 2011-2012, 2014, 2016, Niklas Hauser
+ * Copyright (c) 2011-2012, 2014, 2016, 2020, Niklas Hauser
  * Copyright (c) 2012, Sascha Schade
  * Copyright (c) 2013, Kevin Läufer
  *
@@ -13,63 +13,12 @@
  */
 // ----------------------------------------------------------------------------
 
-/**
- * \file	cxxabi.cpp
- * \brief	Minimal C++ support, no exception handling, no RTTI
- */
-// ----------------------------------------------------------------------------
-
 #include <stdlib.h>                   // for prototypes of malloc() and free()
 #include <new>
 #include <modm/architecture/interface/memory.hpp>
 #include <modm/architecture/interface/assert.hpp>
 
-extern "C"
-{
-	// ------------------------------------------------------------------------
-	void* __dso_handle = (void *) &__dso_handle;
-
-	void
-	__cxa_pure_virtual()
-	{
-		modm_assert_debug(0, "core", "cxa", "purevirtual");
-	}
-
-	// ------------------------------------------------------------------------
-	__extension__ typedef int __guard __attribute__((mode (__DI__)));
-
-	int
-	__cxa_guard_acquire(__guard *g)
-	{
-		return !*(char *)(g);
-	}
-
-	void
-	__cxa_guard_release (__guard *g)
-	{
-		*(char *) g = 1;
-	}
-
-	void
-	__cxa_guard_abort (__guard *)
-	{
-	}
-
-	// ------------------------------------------------------------------------
-	int
-	__aeabi_atexit(void */*object*/, void (*/*destructor*/)(void *), void */*dso_handle*/)
-	{
-		return 0;
-	}
-
-	extern void * malloc_tr(size_t, uint32_t);
-
-	extern void _exit(int);
-	void _exit(int status)
-	{
-		modm_assert(false, "core", "libc", "exit", status);
-	}
-}
+extern "C" void * malloc_tr(size_t, uint32_t);
 
 // ----------------------------------------------------------------------------
 void *