Improve Arm Compiler 6 compatibility

Author: will-v-pi

src/rp2_common/hardware_sync/include/hardware/sync.h

@@ -149,9 +149,11 @@ __force_inline static void __wfi(void) {
  * The DMB (data memory barrier) acts as a memory barrier, all memory accesses prior to this
  * instruction will be observed before any explicit access after the instruction.
  */
+#ifndef __dmb
 __force_inline static void __dmb(void) {
     pico_default_asm_volatile("dmb" : : : "memory");
 }
+#endif
 
 /*! \brief Insert a DSB instruction in to the code path.
  *  \ingroup hardware_sync
@@ -160,9 +162,11 @@ __force_inline static void __dmb(void) {
  * memory barrier (DMB). The DSB operation completes when all explicit memory
  * accesses before this instruction complete.
  */
+#ifndef __dsb
 __force_inline static void __dsb(void) {
     pico_default_asm_volatile("dsb" : : : "memory");
 }
+#endif
 
 /*! \brief Insert a ISB instruction in to the code path.
  *  \ingroup hardware_sync
@@ -171,9 +175,11 @@ __force_inline static void __dsb(void) {
  * so that all instructions following the ISB are fetched from cache or memory again, after
  * the ISB instruction has been completed.
  */
+#ifndef __isb
 __force_inline static void __isb(void) {
     pico_default_asm_volatile("isb" ::: "memory");
 }
+#endif
 
 /*! \brief Acquire a memory fence
  *  \ingroup hardware_sync

src/rp2_common/pico_platform/include/pico/platform.h

@@ -297,7 +297,9 @@ extern "C" {
  */
 #define __no_inline_not_in_flash_func(func_name) __noinline __not_in_flash_func(func_name)
 
+#ifndef __packed_aligned
 #define __packed_aligned __packed __aligned(4)
+#endif
 
 /*! \brief Attribute to force inlining of a function regardless of optimization level
  *  \ingroup pico_platform
@@ -311,8 +313,10 @@ extern "C" {
 #if PICO_C_COMPILER_IS_GNU && (__GNUC__ <= 6 || (__GNUC__ == 7 && (__GNUC_MINOR__ < 3 || !defined(__cplusplus))))
 #define __force_inline inline __always_inline
 #else
+#ifndef __force_inline
 #define __force_inline __always_inline
 #endif
+#endif
 
 /*! \brief Macro to determine the number of elements in an array
  *  \ingroup pico_platform
@@ -484,8 +488,13 @@ static __force_inline uint __get_current_exception(void) {
     return exception;
 }
 
-#define WRAPPER_FUNC(x) __wrap_ ## x
-#define REAL_FUNC(x) __real_ ## x
+#if defined(__IS_COMPILER_ARM_COMPILER_6__)
+    #define WRAPPER_FUNC(__FUNC)     $Sub$$##__FUNC
+    #define REAL_FUNC(__FUNC)        $Super$$## __FUNC
+#else
+    #define WRAPPER_FUNC(x) __wrap_ ## x
+    #define REAL_FUNC(x) __real_ ## x
+#endif
 
 /*! \brief Helper method to busy-wait for at least the given number of cycles
  *  \ingroup pico_platform

src/rp2_common/pico_runtime/runtime.c

@@ -90,6 +90,7 @@ void runtime_init(void) {
             RESETS_RESET_USBCTRL_BITS
     ));
 
+#ifdef __preinit_array_start
     // pre-init runs really early since we need it even for memcpy and divide!
     // (basically anything in aeabi that uses bootrom)
 
@@ -104,6 +105,7 @@ void runtime_init(void) {
     for (void (**p)(void) = &__preinit_array_start; p < &__preinit_array_end; ++p) {
         (*p)();
     }
+#endif
 
     // After calling preinit we have enough runtime to do the exciting maths
     // in clocks_init
@@ -165,6 +167,7 @@ void runtime_init(void) {
     irq_init_priorities();
     alarm_pool_init_default();
 
+#ifdef __init_array_start
     // Start and end points of the constructor list,
     // defined by the linker script.
     extern void (*__init_array_start)(void);
@@ -176,6 +179,7 @@ void runtime_init(void) {
     for (void (**p)(void) = &__init_array_start; p < &__init_array_end; ++p) {
         (*p)();
     }
+#endif
 
 }
 
@@ -189,6 +193,7 @@ void __attribute__((noreturn)) __attribute__((weak)) _exit(__unused int status)
 #endif
 }
 
+#if defined(__clock_t_defined) || defined(_CLOCK_T_DECLARED)
 __attribute__((weak)) void *_sbrk(int incr) {
     extern char end; /* Set by linker.  */
     static char *heap_end;
@@ -259,6 +264,7 @@ __attribute((weak)) int _kill(__unused pid_t pid, __unused int sig) {
 void exit(int status) {
     _exit(status);
 }
+#endif
 
 // incorrect warning from GCC 6
 GCC_Pragma("GCC diagnostic push")