text: /* Copyright (c) 2011-2018, Scott Tsai
  * 
  * All rights reserved.
  * 
  * 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.
  * 
  * 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.
  */
  #ifndef DEBUG_BREAK_H
  
  #ifdef _MSC_VER
  
  #define debug_break __debugbreak
  
  #else
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #define DEBUG_BREAK_USE_TRAP_INSTRUCTION 1
  #define DEBUG_BREAK_USE_BULTIN_TRAP      2
  #define DEBUG_BREAK_USE_SIGTRAP          3
  
  #if defined(__i386__) || defined(__x86_64__)
  #define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_TRAP_INSTRUCTION
  	__inline__ static void trap_instruction(void)
  	{
  		__asm__ volatile("int $0x03");
  	}
  #elif defined(__thumb__)
  #define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_TRAP_INSTRUCTION
  	/* FIXME: handle __THUMB_INTERWORK__ */
  	__attribute__((gnu_inline, always_inline))
  		__inline__ static void trap_instruction(void)
  	{
  		/* See 'arm-linux-tdep.c' in GDB source.
  		* Both instruction sequences below work. */
  #if 1
  		/* 'eabi_linux_thumb_le_breakpoint' */
  		__asm__ volatile(".inst 0xde01");
  #else
  		/* 'eabi_linux_thumb2_le_breakpoint' */
  		__asm__ volatile(".inst.w 0xf7f0a000");
  #endif
  
  		/* Known problem:
  		* After a breakpoint hit, can't 'stepi', 'step', or 'continue' in GDB.
  		* 'step' would keep getting stuck on the same instruction.
  		*
  		* Workaround: use the new GDB commands 'debugbreak-step' and
  		* 'debugbreak-continue' that become available
  		* after you source the script from GDB:
  		*
  		* $ gdb -x debugbreak-gdb.py <... USUAL ARGUMENTS ...>
  		*
  		* 'debugbreak-step' would jump over the breakpoint instruction with
  		* roughly equivalent of:
  		* (gdb) set $instruction_len = 2
  		* (gdb) tbreak *($pc + $instruction_len)
  		* (gdb) jump   *($pc + $instruction_len)
  		*/
  	}
  #elif defined(__arm__) && !defined(__thumb__)
  #define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_TRAP_INSTRUCTION
  	__attribute__((gnu_inline, always_inline))
  		__inline__ static void trap_instruction(void)
  	{
  		/* See 'arm-linux-tdep.c' in GDB source,
  		* 'eabi_linux_arm_le_breakpoint' */
  		__asm__ volatile(".inst 0xe7f001f0");
  		/* Known problem:
  		* Same problem and workaround as Thumb mode */
  	}
  #elif defined(__aarch64__) && defined(__APPLE__)
  #define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_BULTIN_TRAP
  #elif defined(__aarch64__)
  #define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_TRAP_INSTRUCTION
  	__attribute__((gnu_inline, always_inline))
  		__inline__ static void trap_instruction(void)
  	{
  		/* See 'aarch64-tdep.c' in GDB source,
  		* 'aarch64_default_breakpoint' */
  		__asm__ volatile(".inst 0xd4200000");
  	}
  #elif defined(__powerpc__)
  	/* PPC 32 or 64-bit, big or little endian */
  #define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_TRAP_INSTRUCTION
  	__attribute__((gnu_inline, always_inline))
  		__inline__ static void trap_instruction(void)
  	{
  		/* See 'rs6000-tdep.c' in GDB source,
  		* 'rs6000_breakpoint' */
  		__asm__ volatile(".4byte 0x7d821008");
  
  		/* Known problem:
  		* After a breakpoint hit, can't 'stepi', 'step', or 'continue' in GDB.
  		* 'step' stuck on the same instruction ("twge r2,r2").
  		*
  		* The workaround is the same as ARM Thumb mode: use debugbreak-gdb.py
  		* or manually jump over the instruction. */
  	}
  #else
  #define DEBUG_BREAK_IMPL DEBUG_BREAK_USE_SIGTRAP
  #endif
  
  
  #ifndef DEBUG_BREAK_IMPL
  #error "debugbreak.h is not supported on this target"
  #elif DEBUG_BREAK_IMPL == DEBUG_BREAK_USE_TRAP_INSTRUCTION
  	__attribute__((gnu_inline, always_inline))
  		__inline__ static void debug_break(void)
  	{
  		trap_instruction();
  	}
  #elif DEBUG_BREAK_IMPL == DEBUG_BREAK_USE_BULTIN_TRAP
  	__attribute__((gnu_inline, always_inline))
  		__inline__ static void debug_break(void)
  	{
  		__builtin_trap();
  	}
  #elif DEBUG_BREAK_IMPL == DEBUG_BREAK_USE_SIGTRAP
  #include <signal.h>
  	__attribute__((gnu_inline, always_inline))
  		__inline__ static void debug_break(void)
  	{
  		raise(SIGTRAP);
  	}
  #else
  #error "invalid DEBUG_BREAK_IMPL value"
  #endif
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* ifdef _MSC_VER */
  
  #endif /* ifndef DEBUG_BREAK_H */
  