MDK以及DS5等工具中主推的编译器已经更换为armclang编译器。而原来的armcc编译器已经不再更新，只是提供一些更新，所以我就对armclang进行了一些测试。
测试的芯片是STM32，使用ST公司最新推出的Cube HAL库。直接新建一个工程之后，直接将编译器更改为armclang编译不通过。
错误一：提供找不到‘__weak’
解决方案："__weak"的定义是在stm32f1xx_hal_def.h文件中。其中有关于各种编译器的定义部分。理论上armclang应该是会定义__GNU__的，可能由于MDK的bug或是其它原因，这部分并没有定义，所以需要手动增加针对armclang编译器的定义。
修改后代码如下：
/**
******************************************************************************
* @file stm32f1xx_hal_def.h
* @author MCD Application Team
* @version V1.1.1
* @date 12-May-2017
* @brief This file contains HAL common defines, enumeration, macros and
* structures definitions.
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
*/
/**
******************************************************************************
* @author WangWei
* @date 29-Sep-2017
* @brief Add some code for CLANG
******************************************************************************
*/
/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __STM32F1xx_HAL_DEF
#define __STM32F1xx_HAL_DEF
#ifdef __cplusplus
extern "C" {
#endif
/* Includes ------------------------------------------------------------------*/
#include "stm32f1xx.h"
#if defined(USE_HAL_LEGACY)
#include "Legacy/stm32_hal_legacy.h"
#endif
#include <stdio.h>
/* Exported types ------------------------------------------------------------*/
/**
* @brief HAL Status structures definition
*/
typedef enum
{
HAL_OK = 0x00U,
HAL_ERROR = 0x01U,
HAL_BUSY = 0x02U,
HAL_TIMEOUT = 0x03U
} HAL_StatusTypeDef;
/**
* @brief HAL Lock structures definition
*/
typedef enum
{
HAL_UNLOCKED = 0x00U,
HAL_LOCKED = 0x01U
} HAL_LockTypeDef;
/* Exported macro ------------------------------------------------------------*/
#define HAL_MAX_DELAY 0xFFFFFFFFU
#define HAL_IS_BIT_SET(REG, BIT) (((REG) & (BIT)) != RESET)
#define HAL_IS_BIT_CLR(REG, BIT) (((REG) & (BIT)) == RESET)
#define __HAL_LINKDMA(__HANDLE__, __PPP_DMA_FIELD__, __DMA_HANDLE__) \
do{ \
(__HANDLE__)->__PPP_DMA_FIELD__ = &(__DMA_HANDLE__); \
(__DMA_HANDLE__).Parent = (__HANDLE__); \
} while(0U)
#define UNUSED(x) ((void)(x))
/** @brief Reset the Handle's State field.
* @param __HANDLE__: specifies the Peripheral Handle.
* @note This macro can be used for the following purpose:
* - When the Handle is declared as local variable; before passing it as parameter
* to HAL_PPP_Init() for the first time, it is mandatory to use this macro
* to set to 0 the Handle's "State" field.
* Otherwise, "State" field may have any random value and the first time the function
* HAL_PPP_Init() is called, the low level hardware initialization will be missed
* (i.e. HAL_PPP_MspInit() will not be executed).
* - When there is a need to reconfigure the low level hardware: instead of calling
* HAL_PPP_DeInit() then HAL_PPP_Init(), user can make a call to this macro then HAL_PPP_Init().
* In this later function, when the Handle's "State" field is set to 0, it will execute the function
* HAL_PPP_MspInit() which will reconfigure the low level hardware.
* @retval None
*/
#define __HAL_RESET_HANDLE_STATE(__HANDLE__) ((__HANDLE__)->State = 0U)
#if (USE_RTOS == 1U)
/* Reserved for future use */
#error "USE_RTOS should be 0 in the current HAL release"
#else
#define __HAL_LOCK(__HANDLE__) \
do{ \
if((__HANDLE__)->Lock == HAL_LOCKED) \
{ \
return HAL_BUSY; \
} \
else \
{ \
(__HANDLE__)->Lock = HAL_LOCKED; \
} \
}while (0U)
#define __HAL_UNLOCK(__HANDLE__) \
do{ \
(__HANDLE__)->Lock = HAL_UNLOCKED; \
}while (0U)
#endif /* USE_RTOS */
#if defined ( __GNUC__ ) || defined ( __clang__ )
#ifndef __weak
#define __weak __attribute__((weak))
#endif /* __weak */
#ifndef __packed
#define __packed __attribute__((__packed__))
#endif /* __packed */
#endif /* __GNUC__ */
/* Macro to get variable aligned on 4-bytes, for __ICCARM__ the directive "#pragma data_alignment=4" must be used instead */
#if defined (__GNUC__) || defined (__clang__) /* GNU Compiler */
#ifndef __ALIGN_END
#define __ALIGN_END __attribute__ ((aligned (4)))
#endif /* __ALIGN_END */
#ifndef __ALIGN_BEGIN
#define __ALIGN_BEGIN
#endif /* __ALIGN_BEGIN */
#else
#ifndef __ALIGN_END
#define __ALIGN_END
#endif /* __ALIGN_END */
#ifndef __ALIGN_BEGIN
#if defined (__CC_ARM) /* ARM Compiler */
#define __ALIGN_BEGIN __align(4)
#elif defined (__ICCARM__) /* IAR Compiler */
#define __ALIGN_BEGIN
#endif /* __CC_ARM */
#endif /* __ALIGN_BEGIN */
#endif /* __GNUC__ */
/**
* @brief __RAM_FUNC definition
*/
#if defined ( __CC_ARM )
/* ARM Compiler
------------
RAM functions are defined using the toolchain options.
Functions that are executed in RAM should reside in a separate source module.
Using the 'Options for File' dialog you can simply change the 'Code / Const'
area of a module to a memory space in physical RAM.
Available memory areas are declared in the 'Target' tab of the 'Options for Target'
dialog.
*/
#define __RAM_FUNC HAL_StatusTypeDef
#elif defined ( __ICCARM__ )
/* ICCARM Compiler
---------------
RAM functions are defined using a specific toolchain keyword "__ramfunc".
*/
#define __RAM_FUNC __ramfunc HAL_StatusTypeDef
#elif defined ( __GNUC__ ) || defined ( __clang__ )
/* GNU Compiler
------------
RAM functions are defined using a specific toolchain attribute
"__attribute__((section(".RamFunc")))".
*/
#define __RAM_FUNC HAL_StatusTypeDef __attribute__((section(".RamFunc")))
#endif
/**
* @brief __NOINLINE definition
*/
#if defined ( __CC_ARM ) || defined ( __GNUC__ ) || defined ( __clang__ )
/* ARM & GNUCompiler
----------------
*/
#define __NOINLINE __attribute__ ( (noinline) )
#elif defined ( __ICCARM__ )
/* ICCARM Compiler
---------------
*/
#define __NOINLINE _Pragma("optimize = no_inline")
#endif
#ifdef __cplusplus
}
#endif
#endif /* ___STM32F1xx_HAL_DEF */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
错误二：嵌入式汇编部分报错
这个是由于armclang嵌入汇编基本和GNU C类似，不同于armcc编译器，所以这部分需要修改。但是我觉得这是很好的地方，因为这样以后学习STM32的朋友可以更容易的学习linux。