remove GetThreadBacktraceContext; GetBacktrace( x, NULL ) gets the current backtrace

stepmania/src/archutils/Unix/Backtrace.cpp

@@ -22,7 +22,7 @@ void GetSignalBacktraceContext( BacktraceContext *ctx, const ucontext_t *uc )
 	ctx->pid = GetCurrentThreadId();
 }
 
-void GetCurrentBacktraceContext( BacktraceContext *ctx )
+static void GetCurrentBacktraceContext( BacktraceContext *ctx )
 {
 	register void *esp __asm__ ("esp");
 	ctx->esp = (long) esp;
@@ -30,18 +30,6 @@ void GetCurrentBacktraceContext( BacktraceContext *ctx )
 	ctx->ebp = (long) __builtin_frame_address(0);
 }
 
-int GetThreadBacktraceContext( int ThreadID, BacktraceContext *ctx )
-{
-	ctx->pid = ThreadID;
-
-	if( ThreadID != GetCurrentThreadId() )
-		return GetThreadContext( ThreadID, ctx );
-
-	GetCurrentBacktraceContext( ctx );
-
-	return 0;
-}
-
 static const char *itoa(unsigned n)
 {
 	static char ret[32];
@@ -293,16 +281,18 @@ void GetExceptionBacktraceContext( BacktraceContext *ctx, const ExceptionInforma
 	ctx->FramePtr = (void *) exception->registerImage->R1.lo;
 }
 
-void GetCurrentBacktraceContext( BacktraceContext *ctx )
-{
-	ctx->FramePtr = __builtin_return_address(2);
-}
-
 void InitializeBacktrace() { }
 
 void GetBacktrace( const void **buf, size_t size, const BacktraceContext *ctx )
 {
-	Frame *frame = (Frame *) ctx->FramePtr;
+	BacktraceContext CurrentCtx;
+	if( ctx == NULL )
+	{
+		ctx = &CurrentCtx;
+		CurrentCtx.FramePtr = (void *) __builtin_frame_address(0);
+	}
+	
+	const Frame *frame = (Frame *) ctx->FramePtr;
 
 	unsigned i = 0;
 	while( frame && i < size-1 ) // -1 for NULL

stepmania/src/archutils/Unix/Backtrace.h

@@ -28,9 +28,8 @@ void InitializeBacktrace();
 void GetBacktrace( const void **buf, size_t size, const BacktraceContext *ctx = NULL );
 
 /* Set up a BacktraceContext to get a backtrace for a thread.  ThreadID may
- * be the current thread. */
-int GetThreadBacktraceContext( int ThreadID, BacktraceContext *ctx );
-void GetCurrentBacktraceContext( BacktraceContext *ctx );
+ * not be the current thread. */
+bool GetThreadBacktraceContext( int ThreadID, BacktraceContext *ctx );
 
 /* Set up a BacktraceContext to get a backtrace after receiving a signal, given
  * a ucontext_t (see sigaction(2)).  (This interface is UNIX-specific.) */

stepmania/src/archutils/Unix/CrashHandler.cpp

@@ -292,7 +292,10 @@ static void RunCrashHandler( const CrashData *crash )
 	
 	/* Do this early, so functions called below don't end up on the backtrace. */
 	const void *BacktracePointers[BACKTRACE_MAX_SIZE];
-	GetBacktrace( BacktracePointers, BACKTRACE_MAX_SIZE, &crash->ctx );
+	if( crash->type == CrashData::FORCE_CRASH_THIS_THREAD )
+		GetBacktrace( BacktracePointers, BACKTRACE_MAX_SIZE, NULL );
+	else
+		GetBacktrace( BacktracePointers, BACKTRACE_MAX_SIZE, &crash->ctx );
 	
 	/* We need to be very careful, since we're under crash conditions.  Let's fork
 	 * a process and exec ourself to get a clean environment to work in. */
@@ -333,7 +336,6 @@ void ForceCrashHandler( const char *reason )
 	strncpy( crash.reason, reason, sizeof(crash.reason) );
 	crash.reason[ sizeof(crash.reason)-1 ] = 0;
 
-	GetCurrentBacktraceContext( &crash.ctx );
 	RunCrashHandler( &crash );
 }
 

stepmania/src/archutils/Unix/CrashHandlerInternal.h

@@ -22,6 +22,7 @@ struct CrashData
 		// FORCE_CRASH_DEADLOCK
 	} type;
 
+	/* Everything except FORCE_CRASH_THIS_THREAD: */
 	BacktraceContext ctx;
 
 	/* FORCE_CRASH_DEADLOCK only: */

stepmania/src/archutils/Unix/LinuxThreadHelpers.cpp

@@ -147,14 +147,14 @@ int ResumeThread( int ThreadID )
 }
 
 
-/* Get user_regs_struct for a thread.  tid must not be the current thread.
+/* Get a BacktraceContext for a thread.  ThreadID must not be the current thread.
  *
  * tid() is a PID (from getpid) or a TID (from gettid).  Note that this may have kernel compatibility
  * problems, because NPTL is new and its interactions with ptrace() aren't well-defined.
  * If we're on a non-NPTL system, tid is a regular PID. */
-int GetThreadContext( int ThreadID, BacktraceContext *ctx )
+bool GetThreadBacktraceContext( int ThreadID, BacktraceContext *ctx )
 {
-	/* Can't GetThreadContext the current thread. */
+	/* Can't GetThreadBacktraceContext the current thread. */
 	ASSERT( ThreadID != GetCurrentThreadId() );
 
 	/* Attach to the thread. */
@@ -187,7 +187,7 @@ int GetThreadContext( int ThreadID, BacktraceContext *ctx )
 		ASSERT( ret == 0 );
 	}
 
-
+	ctx->pid = ThreadID;
 	ctx->eip = regs.eip;
 	ctx->esp = regs.esp;
 	ctx->ebp = regs.ebp;