Merge changes I8ee7d119,Ibf8d2f54,I5fb92299,I07315f1b

* changes:
  [ion] Initialize static C++ objects
  [liba] Define __aeabi_atexit
  [libaxx] Define __cxa_atexit
  [libaxx] Explicitely define __cxa_pure_virtual

ion/src/device/boot/flash.ld

@@ -36,15 +36,17 @@ SECTIONS {
 
   .text : {
     . = ALIGN(4);
-
-    /* C++ code calls __cxa_pure_virtual when a pure-virtual method is called.
-     * This is an error case, so we just redirect it to abort. */
-    PROVIDE(__cxa_pure_virtual = abort);
-
     *(.text)
     *(.text.*)
   } >FLASH
 
+  .init_array : {
+    . = ALIGN(4);
+    _init_array_start = .;
+    KEEP (*(.init_array*))
+    _init_array_end = .;
+  } >FLASH
+
   .rodata : {
     . = ALIGN(4);
     *(.rodata)

ion/src/device/boot/rt0.cpp

@@ -6,11 +6,17 @@ extern "C" {
 #include <ion.h>
 #include "../device.h"
 
-extern char _data_section_start_flash;
-extern char _data_section_start_ram;
-extern char _data_section_end_ram;
-extern char _bss_section_start_ram;
-extern char _bss_section_end_ram;
+typedef void (*cxx_constructor)();
+
+extern "C" {
+  char _data_section_start_flash;
+  char _data_section_start_ram;
+  char _data_section_end_ram;
+  char _bss_section_start_ram;
+  char _bss_section_end_ram;
+  cxx_constructor _init_array_start;
+  cxx_constructor _init_array_end;
+}
 
 void abort() {
 #ifdef DEBUG
@@ -38,6 +44,16 @@ void start() {
   size_t bssSectionLength = (&_bss_section_end_ram - &_bss_section_start_ram);
   memset(&_bss_section_start_ram, 0, bssSectionLength);
 
+  /* Call static C++ object constructors
+   * The C++ compiler creates an initialization function for each static object.
+   * The linker then stores the address of each of those functions consecutively
+   * between _init_array_start and _init_array_end. So to initialize all C++
+   * static objects we just have to iterate between theses two addresses and
+   * call the pointed function. */
+  for (cxx_constructor * c = &_init_array_start; c<&_init_array_end; c++) {
+    (*c)();
+  }
+
   Ion::Device::init();
 
   ion_app();

liba/Makefile

@@ -56,6 +56,7 @@ tests += $(addprefix liba/test/, \
 # The use of aeabi-rt could be made conditional to an AEABI target.
 # In practice we're always using liba on such a target.
 objs += $(addprefix liba/src/aeabi-rt/, \
+  atexit.o \
   memclr.o \
   memcpy.o \
 )

liba/src/aeabi-rt/atexit.c

@@ -0,0 +1,7 @@
+/* See the "Run-time ABI for the ARM Architecture", Section 4.4.5 */
+
+int __cxa_atexit(void (* dtor)(void * this), void * object, void * handle);
+
+int  __aeabi_atexit(void * object, void (*destroyer)(void *), void * dso_handle) {
+  return __cxa_atexit(destroyer, object, dso_handle);
+}

libaxx/Makefile

@@ -1 +1,2 @@
 objs += $(addprefix libaxx/src/, new.o)
+objs += $(addprefix libaxx/src/cxxabi/, atexit.o pure_virtual.o)

libaxx/src/cxxabi/atexit.cpp

@@ -0,0 +1,14 @@
+/* C++ expects the __dso_handle symbol to be defined to some unique value in
+ * each dynamic shared object. Even though we're not using dynamic loading,
+ * we still have to define __dso_handle. */
+
+void * __dso_handle = nullptr;
+
+/* The __cxa_atexit function registers a function to be called when the program
+ * exits or when a shared library is unloaded.
+ * We don't support shared libraries and our program should never exit, so we
+ * can simply do nothing and return zero. */
+
+extern "C" int __cxa_atexit(void (*dtor)(void *), void * object, void * handle) {
+  return 0;
+}

libaxx/src/cxxabi/pure_virtual.cpp

@@ -0,0 +1,10 @@
+extern "C" {
+#include <stdlib.h>
+}
+
+/* C++ code calls __cxa_pure_virtual when a pure-virtual method is called.
+ * This is an error case, so we just redirect it to abort. */
+
+extern "C" void __cxa_pure_virtual() {
+  abort();
+}