657 lines
22 KiB
C
657 lines
22 KiB
C
/****************************************************************************
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* *
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* GNAT RUN-TIME COMPONENTS *
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* *
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* T R A C E B A C K *
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* *
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* C Implementation File *
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* *
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* Copyright (C) 2000-2016, Free Software Foundation, Inc. *
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* *
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* GNAT is free software; you can redistribute it and/or modify it under *
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* terms of the GNU General Public License as published by the Free Soft- *
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* ware Foundation; either version 3, or (at your option) any later ver- *
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* sion. GNAT is distributed in the hope that it will be useful, but WITH- *
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* OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
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* or FITNESS FOR A PARTICULAR PURPOSE. *
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* *
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* As a special exception under Section 7 of GPL version 3, you are granted *
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* additional permissions described in the GCC Runtime Library Exception, *
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* version 3.1, as published by the Free Software Foundation. *
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* *
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* You should have received a copy of the GNU General Public License and *
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* a copy of the GCC Runtime Library Exception along with this program; *
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* see the files COPYING3 and COPYING.RUNTIME respectively. If not, see *
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* <http://www.gnu.org/licenses/>. *
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* *
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* GNAT was originally developed by the GNAT team at New York University. *
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* Extensive contributions were provided by Ada Core Technologies Inc. *
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* *
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****************************************************************************/
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/* This file contains low level support for stack unwinding using GCC intrinsic
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functions.
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It has been tested on the following configurations:
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PowerPC/AiX
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PowerPC/Darwin
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PowerPC/VxWorks
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PowerPC/LynxOS-178
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SPARC/Solaris
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i386/GNU/Linux
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i386/Solaris
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i386/NT
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i386/OS2
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i386/LynxOS
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Alpha/VxWorks
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Alpha/VMS
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifdef __alpha_vxworks
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#include "vxWorks.h"
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#endif
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#ifdef IN_RTS
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#define POSIX
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#include "tconfig.h"
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#include "tsystem.h"
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#else
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#include "config.h"
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#include "system.h"
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/* We don't want fancy_abort here. */
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#undef abort
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#endif
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extern int __gnat_backtrace (void **, int, void *, void *, int);
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/* The point is to provide an implementation of the __gnat_backtrace function
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above, called by the default implementation of the System.Traceback package.
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We first have a series of target specific implementations, each included
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from a separate C file for readability purposes.
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Then come two flavors of a generic implementation: one relying on static
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assumptions about the frame layout, and the other one using the GCC EH
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infrastructure. The former uses a whole set of macros and structures which
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may be tailored on a per target basis, and is activated as soon as
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USE_GENERIC_UNWINDER is defined. The latter uses a small subset of the
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macro definitions and is activated when USE_GCC_UNWINDER is defined. It is
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only available post GCC 3.3.
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Finally, there is a default dummy implementation, necessary to make the
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linker happy on platforms where the feature is not supported, but where the
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function is still referenced by the default System.Traceback. */
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#define Lock_Task system__soft_links__lock_task
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extern void (*Lock_Task) (void);
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#define Unlock_Task system__soft_links__unlock_task
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extern void (*Unlock_Task) (void);
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/*-------------------------------------*
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*-- Target specific implementations --*
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*-------------------------------------*/
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#if defined (_WIN64) && defined (__SEH__)
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#include <windows.h>
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#define IS_BAD_PTR(ptr) (IsBadCodePtr((FARPROC)ptr))
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int
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__gnat_backtrace (void **array,
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int size,
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void *exclude_min,
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void *exclude_max,
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int skip_frames)
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{
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CONTEXT context;
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UNWIND_HISTORY_TABLE history;
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int i;
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/* Get the context. */
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RtlCaptureContext (&context);
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/* Setup unwind history table (a cached to speed-up unwinding). */
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memset (&history, 0, sizeof (history));
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i = 0;
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while (1)
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{
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PRUNTIME_FUNCTION RuntimeFunction;
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KNONVOLATILE_CONTEXT_POINTERS NvContext;
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ULONG64 ImageBase;
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VOID *HandlerData;
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ULONG64 EstablisherFrame;
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/* Get function metadata. */
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RuntimeFunction = RtlLookupFunctionEntry
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(context.Rip, &ImageBase, &history);
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if (!RuntimeFunction)
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{
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/* In case of failure, assume this is a leaf function. */
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context.Rip = *(ULONG64 *) context.Rsp;
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context.Rsp += 8;
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}
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else
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{
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/* If the last unwinding step failed somehow, stop here. */
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if (IS_BAD_PTR(context.Rip))
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break;
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/* Unwind. */
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memset (&NvContext, 0, sizeof (KNONVOLATILE_CONTEXT_POINTERS));
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RtlVirtualUnwind (0, ImageBase, context.Rip, RuntimeFunction,
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&context, &HandlerData, &EstablisherFrame,
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&NvContext);
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}
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/* 0 means bottom of the stack. */
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if (context.Rip == 0)
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break;
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/* Skip frames. */
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if (skip_frames > 1)
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{
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skip_frames--;
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continue;
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}
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/* Excluded frames. */
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if ((void *)context.Rip >= exclude_min
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&& (void *)context.Rip <= exclude_max)
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continue;
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array[i++] = (void *)(context.Rip - 2);
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if (i >= size)
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break;
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}
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return i;
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}
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#else
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/* No target specific implementation. */
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/*----------------------------------------------------------------*
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*-- Target specific definitions for the generic implementation --*
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*----------------------------------------------------------------*/
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/* The stack layout is specified by the target ABI. The "generic" scheme is
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based on the following assumption:
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The stack layout from some frame pointer is such that the information
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required to compute the backtrace is available at static offsets.
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For a given frame, the information we are interested in is the saved return
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address (somewhere after the call instruction in the caller) and a pointer
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to the caller's frame. The former is the base of the call chain information
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we store in the tracebacks array. The latter allows us to loop over the
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successive frames in the chain.
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To initiate the process, we retrieve an initial frame address using the
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appropriate GCC builtin (__builtin_frame_address).
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This scheme is unfortunately not applicable on every target because the
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stack layout is not necessarily regular (static) enough. On targets where
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this scheme applies, the implementation relies on the following items:
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o struct layout, describing the expected stack data layout relevant to the
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information we are interested in,
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o FRAME_OFFSET, the offset, from a given frame address or frame pointer
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value, at which this layout will be found,
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o FRAME_LEVEL, controls how many frames up we get at to start with,
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from the initial frame pointer we compute by way of the GCC builtin,
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0 is most often the appropriate value. 1 may be necessary on targets
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where return addresses are saved by a function in it's caller's frame
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(e.g. PPC).
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o PC_ADJUST, to account for the difference between a call point (address
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of a call instruction), which is what we want in the output array, and
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the associated return address, which is what we retrieve from the stack.
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o STOP_FRAME, to decide whether we reached the top of the call chain, and
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thus if the process shall stop.
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:
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: stack
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| +----------------+
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| +-------->| : |
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| | | (FRAME_OFFSET) |
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| | | : | (PC_ADJUST)
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| | layout:| return_address ----------------+
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| | | .... | |
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+--------------- next_frame | |
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| | .... | |
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| | | |
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| +----------------+ | +-----+
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| | : |<- Base fp | | : |
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| | (FRAME_OFFSET) | (FRAME_LEVEL) | | : |
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| | : | +---> | [1]
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| layout:| return_address --------------------> | [0]
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| | ... | (PC_ADJUST) +-----+
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+---------- next_frame | traceback[]
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| ... |
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+----------------+
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o BASE_SKIP,
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Since we inherently deal with return addresses, there is an implicit shift
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by at least one for the initial point we are able to observe in the chain.
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On some targets (e.g. sparc-solaris), the first return address we can
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easily get without special code is even our caller's return address, so
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there is a initial shift of two.
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BASE_SKIP represents this initial shift, which is the minimal "skip_frames"
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value we support. We could add special code for the skip_frames < BASE_SKIP
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cases. This is not done currently because there is virtually no situation
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in which this would be useful.
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Finally, to account for some ABI specificities, a target may (but does
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not have to) define:
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o FORCE_CALL, to force a call to a dummy function at the very beginning
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of the computation. See the PPC AIX target for an example where this
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is useful.
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o FETCH_UP_FRAME, to force an invocation of __builtin_frame_address with a
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positive argument right after a possibly forced call even if FRAME_LEVEL
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is 0. See the SPARC Solaris case for an example where this is useful.
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*/
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/*------------------- Darwin 8 (OSX 10.4) or newer ----------------------*/
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#if defined (__APPLE__) \
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&& defined (__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) \
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&& __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1040
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#define USE_GCC_UNWINDER
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#if defined (__i386__) || defined (__x86_64__)
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#define PC_ADJUST -2
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#elif defined (__ppc__) || defined (__ppc64__)
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#define PC_ADJUST -4
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#elif defined (__arm__)
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#define PC_ADJUST -2
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#elif defined (__arm64__)
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#define PC_ADJUST -4
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#else
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#error Unhandled darwin architecture.
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#endif
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/*---------------------------- x86 *BSD --------------------------------*/
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#elif defined (__i386__) && \
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( defined (__NetBSD__) || defined (__FreeBSD__) || defined (__OpenBSD__) )
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#define USE_GCC_UNWINDER
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/* The generic unwinder is not used for this target because the default
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implementation doesn't unwind on the BSD platforms. AMD64 targets use the
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gcc unwinder for all platforms, so let's keep i386 consistent with that.
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*/
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#define PC_ADJUST -2
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/* The minimum size of call instructions on this architecture is 2 bytes */
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/*---------------------- ARM VxWorks ------------------------------------*/
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#elif (defined (ARMEL) && defined (__vxworks))
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#include "vxWorks.h"
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#include "version.h"
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#define USE_GCC_UNWINDER
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#define PC_ADJUST -2
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#if (_WRS_VXWORKS_MAJOR >= 7)
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#define USING_ARM_UNWINDING 1
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#endif
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/*---------------------- PPC AIX/PPC Lynx 178/Older Darwin --------------*/
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#elif ((defined (_POWER) && defined (_AIX)) || \
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(defined (__powerpc__) && defined (__Lynx__) && !defined(__ELF__)) || \
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(defined (__ppc__) && defined (__APPLE__)))
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#define USE_GENERIC_UNWINDER
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struct layout
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{
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struct layout *next;
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void *pad;
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void *return_address;
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};
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#define FRAME_OFFSET(FP) 0
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#define PC_ADJUST -4
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/* Eventhough the base PPC ABI states that a toplevel frame entry
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should to feature a null backchain, AIX might expose a null return
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address instead. */
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/* Then LynxOS-178 features yet another variation, with return_address
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== &<entrypoint>, with two possible entry points (one for the main
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process and one for threads). Beware that &bla returns the address
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of a descriptor when "bla" is a function. Getting the code address
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requires an extra dereference. */
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#if defined (__Lynx__)
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extern void __start(); /* process entry point. */
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extern void __runnit(); /* thread entry point. */
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#define EXTRA_STOP_CONDITION(CURRENT) \
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((CURRENT)->return_address == *(void**)&__start \
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|| (CURRENT)->return_address == *(void**)&__runnit)
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#else
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#define EXTRA_STOP_CONDITION(CURRENT) (0)
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#endif
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#define STOP_FRAME(CURRENT, TOP_STACK) \
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(((void *) (CURRENT) < (TOP_STACK)) \
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|| (CURRENT)->return_address == NULL \
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|| EXTRA_STOP_CONDITION(CURRENT))
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/* The PPC ABI has an interesting specificity: the return address saved by a
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function is located in it's caller's frame, and the save operation only
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takes place if the function performs a call.
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To have __gnat_backtrace retrieve its own return address, we then
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define ... */
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#define FORCE_CALL 1
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#define FRAME_LEVEL 1
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#define BASE_SKIP 1
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/*----------- PPC ELF (GNU/Linux & VxWorks & Lynx178e) -------------------*/
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#elif (defined (_ARCH_PPC) && defined (__vxworks)) || \
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(defined (__powerpc__) && defined (__Lynx__) && defined(__ELF__)) || \
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(defined (__linux__) && defined (__powerpc__))
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#define USE_GENERIC_UNWINDER
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struct layout
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{
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struct layout *next;
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void *return_address;
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};
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#define FORCE_CALL 1
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#define FRAME_LEVEL 1
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/* See the PPC AIX case for an explanation of these values. */
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#define FRAME_OFFSET(FP) 0
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#define PC_ADJUST -4
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/* According to the base PPC ABI, a toplevel frame entry should feature
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a null backchain. What happens at signal handler frontiers isn't so
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well specified, so we add a safety guard on top. */
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#define STOP_FRAME(CURRENT, TOP_STACK) \
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((CURRENT)->next == 0 || ((long)(CURRENT)->next % __alignof__(void*)) != 0)
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#define BASE_SKIP 1
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/*-------------------------- SPARC Solaris -----------------------------*/
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#elif defined (__sun__) && defined (__sparc__)
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#define USE_GENERIC_UNWINDER
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/* These definitions are inspired from the Appendix D (Software
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Considerations) of the SPARC V8 architecture manual. */
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struct layout
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{
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struct layout *next;
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void *return_address;
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};
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#ifdef __arch64__
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#define STACK_BIAS 2047 /* V9 ABI */
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#else
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#define STACK_BIAS 0 /* V8 ABI */
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#endif
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#define FRAME_LEVEL 0
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#define FRAME_OFFSET(FP) (14 * sizeof (void*) + (FP ? STACK_BIAS : 0))
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#define PC_ADJUST 0
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#define STOP_FRAME(CURRENT, TOP_STACK) \
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((CURRENT)->return_address == 0|| (CURRENT)->next == 0 \
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|| (void *) (CURRENT) < (TOP_STACK))
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/* The SPARC register windows need to be flushed before we may access them
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from the stack. This is achieved by way of builtin_frame_address only
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when the "count" argument is positive, so force at least one such call. */
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#define FETCH_UP_FRAME_ADDRESS
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#define BASE_SKIP 2
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/* From the frame pointer of frame N, we are accessing the flushed register
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window of frame N-1 (positive offset from fp), in which we retrieve the
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saved return address. We then end up with our caller's return address. */
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/*---------------------------- x86 & x86_64 ---------------------------------*/
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#elif defined (__i386__) || defined (__x86_64__)
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#if defined (__WIN32)
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#include <windows.h>
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#define IS_BAD_PTR(ptr) (IsBadCodePtr((FARPROC)ptr))
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#elif defined (__sun__)
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#define IS_BAD_PTR(ptr) ((unsigned long)ptr == -1UL)
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#else
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#define IS_BAD_PTR(ptr) 0
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#endif
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/* Use the dwarf2 unwinder when we expect to have dwarf2 tables at
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hand. Backtraces will reliably stop on frames missing such tables,
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but our only alternative is the generic unwinder which requires
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compilation forcing a frame pointer to be reliable. */
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#if (defined (__x86_64__) || defined (__linux__)) && !defined (__USING_SJLJ_EXCEPTIONS__)
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#define USE_GCC_UNWINDER
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#else
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#define USE_GENERIC_UNWINDER
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#endif
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struct layout
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{
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struct layout *next;
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void *return_address;
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};
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#define FRAME_LEVEL 1
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/* builtin_frame_address (1) is expected to work on this family of targets,
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and (0) might return the soft stack pointer, which does not designate a
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location where a backchain and a return address might be found. */
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#define FRAME_OFFSET(FP) 0
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#define PC_ADJUST -2
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#define STOP_FRAME(CURRENT, TOP_STACK) \
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(IS_BAD_PTR((long)(CURRENT)) \
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|| IS_BAD_PTR((long)(CURRENT)->return_address) \
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|| (CURRENT)->return_address == 0 \
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|| (void *) ((CURRENT)->next) < (TOP_STACK) \
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|| (void *) (CURRENT) < (TOP_STACK))
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#define BASE_SKIP (1+FRAME_LEVEL)
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/* On i386 architecture we check that at the call point we really have a call
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insn. Possible call instructions are:
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call addr16 E8 xx xx xx xx
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call reg FF Dx
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call off(reg) FF xx xx
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lcall addr seg 9A xx xx xx xx xx xx
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This check will not catch all cases but it will increase the backtrace
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reliability on this architecture.
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*/
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#define VALID_STACK_FRAME(ptr) \
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(!IS_BAD_PTR(ptr) \
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&& (((*((ptr) - 3) & 0xff) == 0xe8) \
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|| ((*((ptr) - 5) & 0xff) == 0x9a) \
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|| ((*((ptr) - 1) & 0xff) == 0xff) \
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|| (((*(ptr) & 0xd0ff) == 0xd0ff))))
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/*----------------------------- ia64 ---------------------------------*/
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#elif defined (__ia64__) && (defined (__linux__) || defined (__hpux__))
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#define USE_GCC_UNWINDER
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/* Use _Unwind_Backtrace driven exceptions on ia64 HP-UX and ia64
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GNU/Linux, where _Unwind_Backtrace is provided by the system unwind
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library. On HP-UX 11.23 this requires patch PHSS_33352, which adds
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_Unwind_Backtrace to the system unwind library. */
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#define PC_ADJUST -4
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#endif
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/*---------------------------------------------------------------------*
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*-- The post GCC 3.3 infrastructure based implementation --*
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*---------------------------------------------------------------------*/
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#if defined (USE_GCC_UNWINDER) && (__GNUC__ * 10 + __GNUC_MINOR__ > 33)
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/* Conditioning the inclusion on the GCC version is useful to avoid bootstrap
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path problems, since the included file refers to post 3.3 functions in
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libgcc, and the stage1 compiler is unlikely to be linked against a post 3.3
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library. It actually disables the support for backtraces in this compiler
|
|
for targets defining USE_GCC_UNWINDER, which is OK since we don't use the
|
|
traceback capability in the compiler anyway.
|
|
|
|
The condition is expressed the way above because we cannot reliably rely on
|
|
any other macro from the base compiler when compiling stage1. */
|
|
|
|
#ifdef USING_ARM_UNWINDING
|
|
/* This value is not part of the enumerated reason codes defined in unwind.h
|
|
for ARM style unwinding, but is used in the included "C" code, so we
|
|
define it to a reasonable value to avoid a compilation error. */
|
|
#define _URC_NORMAL_STOP 0
|
|
#endif
|
|
#include "tb-gcc.c"
|
|
|
|
/*------------------------------------------------------------------*
|
|
*-- The generic implementation based on frame layout assumptions --*
|
|
*------------------------------------------------------------------*/
|
|
|
|
#elif defined (USE_GENERIC_UNWINDER)
|
|
|
|
#ifndef CURRENT_STACK_FRAME
|
|
# define CURRENT_STACK_FRAME ({ char __csf; &__csf; })
|
|
#endif
|
|
|
|
#ifndef VALID_STACK_FRAME
|
|
#define VALID_STACK_FRAME(ptr) 1
|
|
#endif
|
|
|
|
#ifndef MAX
|
|
#define MAX(x,y) ((x) > (y) ? (x) : (y))
|
|
#endif
|
|
|
|
#ifndef FORCE_CALL
|
|
#define FORCE_CALL 0
|
|
#endif
|
|
|
|
/* Make sure the function is not inlined. */
|
|
static void forced_callee (void) __attribute__ ((noinline));
|
|
|
|
static void forced_callee (void)
|
|
{
|
|
/* Make sure the function is not pure. */
|
|
volatile int i __attribute__ ((unused)) = 0;
|
|
}
|
|
|
|
int
|
|
__gnat_backtrace (void **array,
|
|
int size,
|
|
void *exclude_min,
|
|
void *exclude_max,
|
|
int skip_frames)
|
|
{
|
|
struct layout *current;
|
|
void *top_frame;
|
|
void *top_stack ATTRIBUTE_UNUSED;
|
|
int cnt = 0;
|
|
|
|
if (FORCE_CALL)
|
|
forced_callee ();
|
|
|
|
/* Force a call to builtin_frame_address with a positive argument
|
|
if required. This is necessary e.g. on SPARC to have the register
|
|
windows flushed before we attempt to access them on the stack. */
|
|
#if defined (FETCH_UP_FRAME_ADDRESS) && (FRAME_LEVEL == 0)
|
|
__builtin_frame_address (1);
|
|
#endif
|
|
|
|
top_frame = __builtin_frame_address (FRAME_LEVEL);
|
|
top_stack = CURRENT_STACK_FRAME;
|
|
current = (struct layout *) ((size_t) top_frame + FRAME_OFFSET (0));
|
|
|
|
/* Skip the number of calls we have been requested to skip, accounting for
|
|
the BASE_SKIP parameter.
|
|
|
|
FRAME_LEVEL is meaningless for the count adjustment. It impacts where we
|
|
start retrieving data from, but how many frames "up" we start at is in
|
|
BASE_SKIP by definition. */
|
|
|
|
skip_frames = MAX (0, skip_frames - BASE_SKIP);
|
|
|
|
while (cnt < skip_frames)
|
|
{
|
|
current = (struct layout *) ((size_t) current->next + FRAME_OFFSET (1));
|
|
cnt++;
|
|
}
|
|
|
|
cnt = 0;
|
|
while (cnt < size)
|
|
{
|
|
if (STOP_FRAME (current, top_stack) ||
|
|
!VALID_STACK_FRAME(((char *) current->return_address) + PC_ADJUST))
|
|
break;
|
|
|
|
if (current->return_address < exclude_min
|
|
|| current->return_address > exclude_max)
|
|
array[cnt++] = ((char *) current->return_address) + PC_ADJUST;
|
|
|
|
current = (struct layout *) ((size_t) current->next + FRAME_OFFSET (1));
|
|
}
|
|
|
|
return cnt;
|
|
}
|
|
|
|
#else
|
|
|
|
/* No target specific implementation and neither USE_GCC_UNWINDER nor
|
|
USE_GENERIC_UNWINDER defined. */
|
|
|
|
/*------------------------------*
|
|
*-- The dummy implementation --*
|
|
*------------------------------*/
|
|
|
|
int
|
|
__gnat_backtrace (void **array ATTRIBUTE_UNUSED,
|
|
int size ATTRIBUTE_UNUSED,
|
|
void *exclude_min ATTRIBUTE_UNUSED,
|
|
void *exclude_max ATTRIBUTE_UNUSED,
|
|
int skip_frames ATTRIBUTE_UNUSED)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
#endif
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|