runtime/src/common/RTStack.i3


Copyright (C) 1994, Digital Equipment Corp.

UNSAFE INTERFACE RTStack;

IMPORT RTMachine;
This interface defines the low-level routines used to traverse the runtime stack. Not all platforms support these routines.

CONST Has_walker = RTMachine.Has_stack_walker;
Indicates whether this platform has a stack walker. If Has_walker is FALSE, it is a checked runtime error to call any of the routines described below.

TYPE Frame = RTMachine.FrameInfo;
A machine-dependent type that minimally includes fields named pc and sp.

<*EXTERNAL "RTStack__GetThreadFrame" *>
PROCEDURE GetThreadFrame (VAR(*OUT*) f: Frame;  start: ADDRESS;  len: INTEGER);
Return in f the frame of the thread whose machine state is in bytes [start .. start+len). Returns with f.pc=NIL on failure.

<*EXTERNAL "RTStack__CurFrame" *>
PROCEDURE CurrentFrame (VAR(*OUT*) f: Frame);
Return in f the frame of its caller. Returns with f.pc=NIL on failure.

<*EXTERNAL "RTStack__PrevFrame" *>
PROCEDURE PreviousFrame (READONLY callee: Frame;  VAR(*OUT*)caller: Frame);
Return in caller the stack frame that called callee. Returns with pc = NIL if callee is the first frame on the stack or its predecessor is ill-formed.

<*EXTERNAL "RTStack__Unwind" *>
PROCEDURE Unwind (READONLY f: Frame);
Restore the machine state back to the frame f. All callee-saved registers must be restored to the state they were in when frame f made its last call. Note that if the unwind operation encounters a signal handler frame, it must also restore the caller-saved registers.

<*EXTERNAL "RTStack__ProcName" *>
PROCEDURE ProcName (READONLY f: Frame): ADDRESS;
Return the null-terminated constant string that names the procedure corresponding to the stack frame f. Returns NIL if no name is known.

END RTStack.

interface RTMachine is in: