1 files changed, 125 insertions, 0 deletions
diff --git a/libdevcore/debugbreak.h b/libdevcore/debugbreak.h
new file mode 100644
index 00000000..65612a34
--- /dev/null
+++ b/libdevcore/debugbreak.h
@@ -0,0 +1,125 @@
+/* Copyright (c) 2013, 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
+#define DEBUG_BREAK_H
+
+#if defined(_MSC_VER) || defined(__MINGW32__)
+
+#define debug_break __debugbreak
+
+#else
+
+#include <signal.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum {
+	/* gcc optimizers consider code after __builtin_trap() dead.
+	 * Making __builtin_trap() unsuitable for breaking into the debugger */
+	DEBUG_BREAK_PREFER_BUILTIN_TRAP_TO_SIGTRAP = 0,
+};
+
+#if defined(__i386__) || defined(__x86_64__)
+enum { HAVE_TRAP_INSTRUCTION = 1, };
+__attribute__((gnu_inline, always_inline))
+static void __inline__ trap_instruction(void)
+{
+	__asm__ volatile("int $0x03");
+}
+#elif defined(__thumb__)
+enum { HAVE_TRAP_INSTRUCTION = 1, };
+/* FIXME: handle __THUMB_INTERWORK__ */
+__attribute__((gnu_inline, always_inline))
+static void __inline__ trap_instruction(void)
+{
+	/* See 'arm-linux-tdep.c' in GDB source.
+	 * Both instruction sequences below works. */
+#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' stuck on the same instruction.
+	 *
+	 * Workaround: a new GDB command,
+	 * 'debugbreak-step' is defined in debugbreak-gdb.py
+	 * that does:
+	 * (gdb) set $instruction_len = 2
+	 * (gdb) tbreak *($pc + $instruction_len)
+	 * (gdb) jump   *($pc + $instruction_len)
+	 */
+}
+#elif defined(__arm__) && !defined(__thumb__)
+enum { HAVE_TRAP_INSTRUCTION = 1, };
+__attribute__((gnu_inline, always_inline))
+static void __inline__ trap_instruction(void)
+{
+	/* See 'arm-linux-tdep.c' in GDB source,
+	 * 'eabi_linux_arm_le_breakpoint' */
+	__asm__ volatile(".inst 0xe7f001f0");
+	/* Has same known problem and workaround
+	 * as Thumb mode */
+}
+#else
+enum { HAVE_TRAP_INSTRUCTION = 0, };
+#endif
+
+__attribute__((gnu_inline, always_inline))
+static void __inline__ debug_break(void)
+{
+	if (HAVE_TRAP_INSTRUCTION) {
+#if defined(ETH_EMSCRIPTEN)
+		asm("debugger");
+#else
+		trap_instruction();
+#endif
+	} else if (DEBUG_BREAK_PREFER_BUILTIN_TRAP_TO_SIGTRAP) {
+		 /* raises SIGILL on Linux x86{,-64}, to continue in gdb:
+		  * (gdb) handle SIGILL stop nopass
+		  * */
+		__builtin_trap();
+	} else {
+		raise(SIGTRAP);
+	}
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+#endif