Various small fixes towards building with other compilers (hathach#1285)

* Fix various non-GCC warnings (no effect on GCC)
* Reduce use of typeof since non GCC compilers may not support it
* Introduce PICO_C_COMPILER_IS_GNU, PICO_C_COMPILER_IS_CLANG, PICO_C_COMPILER_IS_IAR to CMake as if (CMAKE_C_COMPILER_ID STREQUAL "xxx") is a bit verbose
* Use "unified_asm" macro for all inline asm (it is "volatile __asm" on GNU with a .syntex unified)
* Use NOLOAD instead of COPY in linker scripts (arguably more correct anyway)
* Use the same style for setting _etext in all 4 linker scripts (to the beginning of .data). Clang aligns .data on a 16 byte boundary. Note ideally we'd
  add a new symbol __data_source, however that would break backwards compatibility with existing user linker scripts
* Use "a" for .stack, .heap sections because clang complains otherwise, and they are explicitly NOLOAD anyway
* Avoid duplicating __sev, __wfe, __wfi which Clang sometimes seems to provide as built-ins
* Add missing kitchen_sink_blocked_ram binary
* Allow build with LLVM Embedded Toolchain Form ARM v 14.0.0 (unsupported atm)

Author: kilograham

CMakeLists.txt

@@ -9,6 +9,13 @@ if (NOT TARGET _pico_sdk_inclusion_marker)
 
     project(pico_sdk C CXX ASM)
 
+    string(REGEX MATCH "Clang" PICO_C_COMPILER_IS_CLANG "${CMAKE_C_COMPILER_ID}")
+    string(REGEX MATCH "GNU" PICO_C_COMPILER_IS_GNU "${CMAKE_C_COMPILER_ID}")
+    string(REGEX MATCH "IAR" PICO_C_COMPILER_IS_IAR "${CMAKE_C_COMPILER_ID}")
+    pico_register_common_scope_var(PICO_C_COMPILER_IS_CLANG)
+    pico_register_common_scope_var(PICO_C_COMPILER_IS_GNU)
+    pico_register_common_scope_var(PICO_C_COMPILER_IS_IAR)
+
     message("Build type is ${CMAKE_BUILD_TYPE}")
     if ("${CMAKE_BUILD_TYPE}" STREQUAL "Debug")
         if (PICO_DEOPTIMIZED_DEBUG)

cmake/preload/toolchains/pico_arm_clang.cmake

@@ -1,4 +1,5 @@
-# NOTE: THIS IS A WIP ONLY PICO_ARM_GCC IS CURRENTLY SUPPORTED
+# NOTE: THIS IS A WIP ONLY PICO_ARM_GCC IS CURRENTLY SUPPORTED, however should work with LLVM Embedded Toolchain for ARM
+# version 14.0.0 https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/releases/tag/release-14.0.0
 # todo there is probably a more "cmake" way of doing this going thru the standard path with our "PICO" platform
 #  i.e. CMake<Lang>Information and whatnot
 include(${CMAKE_CURRENT_LIST_DIR}/find_compiler.cmake)
@@ -37,9 +38,10 @@ set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
 set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 
-include_directories(/usr/include/newlib)
-
 option(PICO_DEOPTIMIZED_DEBUG "Build debug builds with -O0" 0)
 
-set(ARM_TOOLCHAIN_COMMON_FLAGS " --target=arm-none-eabi -mcpu=cortex-m0plus -mthumb")
+# Oz is preferred for Clang (verses CMake default -Os) see also https://gitlab.kitware.com/cmake/cmake/-/issues/22458
+set(CMAKE_C_FLAGS_MINSIZEREL "-Oz -DNDEBUG")
+
+set(ARM_TOOLCHAIN_COMMON_FLAGS "--target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m --sysroot ${PICO_COMPILER_DIR}/../lib/clang-runtimes/armv6m_soft_nofp")
 include(${CMAKE_CURRENT_LIST_DIR}/set_flags.cmake)

src/common/pico_binary_info/include/pico/binary_info/code.h

@@ -16,12 +16,12 @@
 #include "pico/binary_info/structure.h"
 
 #if !PICO_NO_BINARY_INFO
-#define __bi_decl(name, bi, section_prefix, attr) static const attr __attribute__((section(section_prefix __STRING(name)))) struct _binary_info_core *name = bi
+#define __bi_decl(name, bi, section_prefix, attr) static const attr __attribute__((section(section_prefix __STRING(name)))) struct _binary_info_core *const name = bi
 #define __bi_lineno_var_name __CONCAT(__bi_, __LINE__)
 #define __bi_ptr_lineno_var_name __CONCAT(__bi_ptr, __LINE__)
 #define __bi_enclosure_check_lineno_var_name __CONCAT(_error_bi_is_missing_enclosing_decl_,__LINE__)
 #define __bi_mark_enclosure static const __unused int __bi_enclosure_check_lineno_var_name=0;
-#if !defined(__GNUC__) || __cplusplus || __GNUC__ >= 8
+#if __cplusplus || __GNUC__ >= 8
 #define __bi_enclosure_check(x) (x + __bi_enclosure_check_lineno_var_name)
 #else
 // skip the version check on older GCC non C++, as it doesn't compile.. this is only here to catch the
@@ -39,10 +39,10 @@
  * binary information declared this way will also be stripped
  * \ingroup pico_binary_info
  */
-#define bi_decl_if_func_used(_decl) ({__bi_mark_enclosure _decl; __bi_decl(__bi_ptr_lineno_var_name, &__bi_lineno_var_name.core, ".binary_info.", ); *(volatile uint8_t *)&__bi_ptr_lineno_var_name;});
+#define bi_decl_if_func_used(_decl) ({__bi_mark_enclosure _decl; __bi_decl(__bi_ptr_lineno_var_name, &__bi_lineno_var_name.core, ".binary_info.", ); *(const volatile uint8_t *)&__bi_ptr_lineno_var_name;});
 
 #define bi_decl_with_attr(_decl, _attr) __bi_mark_enclosure _attr _decl; __bi_decl(__bi_ptr_lineno_var_name, &__bi_lineno_var_name.core, ".binary_info.keep.", __used);
-#define bi_decl_if_func_used_with_attr(_decl, _attr) ({__bi_mark_enclosure _attr _decl; __bi_decl(__bi_ptr_lineno_var_name, &__bi_lineno_var_name.core, ".binary_info.", ); *(volatile uint8_t *)&__bi_ptr_lineno_var_name;});
+#define bi_decl_if_func_used_with_attr(_decl, _attr) ({__bi_mark_enclosure _attr _decl; __bi_decl(__bi_ptr_lineno_var_name, &__bi_lineno_var_name.core, ".binary_info.", ); *(const volatile uint8_t *)&__bi_ptr_lineno_var_name;});
 #else
 #define __bi_decl(bi, name, attr)
 #define bi_decl_with_attr(_decl, _attr)

src/common/pico_sync/sem.c

@@ -15,7 +15,12 @@ void sem_init(semaphore_t *sem, int16_t initial_permits, int16_t max_permits) {
 }
 
 int __time_critical_func(sem_available)(semaphore_t *sem) {
+#ifdef __GNUC__
     return *(volatile typeof(sem->permits) *) &sem->permits;
+#else
+    static_assert(sizeof(sem->permits) == 2, "");
+    return *(volatile int16_t *) &sem->permits;
+#endif
 }
 
 void __time_critical_func(sem_acquire_blocking)(semaphore_t *sem) {

src/common/pico_time/time.c

@@ -22,7 +22,7 @@ typedef struct alarm_pool_entry {
     void *user_data;
 } alarm_pool_entry_t;
 
-typedef struct alarm_pool {
+struct alarm_pool {
     pheap_t *heap;
     spin_lock_t *lock;
     alarm_pool_entry_t *entries;
@@ -32,7 +32,7 @@ typedef struct alarm_pool {
     alarm_id_t alarm_in_progress; // this is set during a callback from the IRQ handler... it can be cleared by alarm_cancel to prevent repeats
     uint8_t hardware_alarm_num;
     uint8_t core_num;
-} alarm_pool_t;
+};
 
 #if !PICO_TIME_DEFAULT_ALARM_POOL_DISABLED
 // To avoid bringing in calloc, we statically allocate the arrays and the heap

src/common/pico_util/include/pico/util/queue.h

@@ -59,7 +59,7 @@ void queue_init_with_spinlock(queue_t *q, uint element_size, uint element_count,
  * \param element_count Maximum number of entries in the queue
  */
 static inline void queue_init(queue_t *q, uint element_size, uint element_count) {
-    return queue_init_with_spinlock(q, element_size, element_count, next_striped_spin_lock_num());
+    queue_init_with_spinlock(q, element_size, element_count, next_striped_spin_lock_num());
 }
 
 /*! \brief Destroy the specified queue.

src/rp2_common/boot_stage2/CMakeLists.txt

@@ -40,9 +40,9 @@ function(pico_define_boot_stage2 NAME SOURCES)
     )
 
     # todo bit of an abstraction failure - revisit for Clang support anyway
-    if (CMAKE_C_COMPILER_ID STREQUAL "Clang")
+    if (PICO_C_COMPILER_IS_CLANG)
         target_link_options(${NAME} PRIVATE "-nostdlib")
-    else ()
+    elseif (PICO_C_COMPILER_IS_GNU)
         target_link_options(${NAME} PRIVATE "--specs=nosys.specs")
         target_link_options(${NAME} PRIVATE "-nostartfiles")
     endif ()

src/rp2_common/hardware_claim/claim.c

@@ -6,7 +6,7 @@
 
 #include "hardware/claim.h"
 
-uint32_t hw_claim_lock() {
+uint32_t hw_claim_lock(void) {
     return spin_lock_blocking(spin_lock_instance(PICO_SPINLOCK_ID_HARDWARE_CLAIM));
 }
 

src/rp2_common/hardware_clocks/clocks.c

@@ -78,8 +78,7 @@ bool clock_configure(enum clock_index clk_index, uint32_t src, uint32_t auxsrc,
             // Note XOSC_COUNT is not helpful here because XOSC is not
             // necessarily running, nor is timer... so, 3 cycles per loop:
             uint delay_cyc = configured_freq[clk_sys] / configured_freq[clk_index] + 1;
-            asm volatile (
-                ".syntax unified \n\t"
+            unified_asm (
                 "1: \n\t"
                 "subs %0, #1 \n\t"
                 "bne 1b"

src/rp2_common/hardware_divider/include/hardware/divider.h

@@ -85,10 +85,10 @@ static inline void hw_divider_wait_ready(void) {
     // we use one less register and instruction than gcc which uses a TST instruction
 
     uint32_t tmp; // allow compiler to pick scratch register
-    asm volatile (
+    unified_asm (
     "hw_divider_result_loop_%=:"
     "ldr %0, [%1, %2]\n\t"
-    "lsr %0, #1\n\t"
+    "lsrs %0, %0, #1\n\t"
     "bcc hw_divider_result_loop_%=\n\t"
     : "=&l" (tmp)
     : "l" (sio_hw), "I" (SIO_DIV_CSR_OFFSET)
@@ -105,7 +105,8 @@ static inline void hw_divider_wait_ready(void) {
  */
 static inline divmod_result_t hw_divider_result_nowait(void) {
     // as ugly as this looks it is actually quite efficient
-    divmod_result_t rc = (((divmod_result_t) sio_hw->div_remainder) << 32u) | sio_hw->div_quotient;
+    divmod_result_t rc = ((divmod_result_t) sio_hw->div_remainder) << 32u;
+    rc |= sio_hw->div_quotient;
     return rc;
 }
 
@@ -295,7 +296,7 @@ static inline int32_t hw_divider_remainder_s32(int32_t a, int32_t b) {
  *  \ingroup hardware_divider
  */
 static inline void hw_divider_pause(void) {
-    asm volatile (
+    unified_asm (
     "b _1_%=\n"
     "_1_%=:\n"
     "b _2_%=\n"