628 lines
24 KiB
Ada
628 lines
24 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . T R A C E B A C K --
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-- (HP/UX Version) --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 2009-2015, 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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with Ada.Unchecked_Conversion;
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package body System.Traceback is
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-- This package implements the backtracing facility by way of a dedicated
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-- HP library for stack unwinding described in the "Runtime Architecture
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-- Document".
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pragma Linker_Options ("/usr/lib/libcl.a");
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-- The library basically offers services to fetch information about a
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-- "previous" frame based on information about a "current" one.
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type Current_Frame_Descriptor is record
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cur_fsz : Address; -- Frame size of current routine.
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cur_sp : Address; -- The current value of stack pointer.
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cur_rls : Address; -- PC-space of the caller.
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cur_rlo : Address; -- PC-offset of the caller.
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cur_dp : Address; -- Data Pointer of the current routine.
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top_rp : Address; -- Initial value of RP.
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top_mrp : Address; -- Initial value of MRP.
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top_sr0 : Address; -- Initial value of sr0.
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top_sr4 : Address; -- Initial value of sr4.
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top_r3 : Address; -- Initial value of gr3.
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cur_r19 : Address; -- GR19 value of the calling routine.
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top_r4 : Address; -- Initial value of gr4.
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dummy : Address; -- Reserved.
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out_rlo : Address; -- PC-offset of the caller after get_previous.
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end record;
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type Previous_Frame_Descriptor is record
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prev_fsz : Address; -- frame size of calling routine.
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prev_sp : Address; -- SP of calling routine.
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prev_rls : Address; -- PC_space of calling routine's caller.
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prev_rlo : Address; -- PC_offset of calling routine's caller.
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prev_dp : Address; -- DP of calling routine.
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udescr0 : Address; -- low word of calling routine's unwind desc.
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udescr1 : Address; -- high word of calling routine's unwind desc.
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ustart : Address; -- start of the unwind region.
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uend : Address; -- end of the unwind region.
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uw_index : Address; -- index into the unwind table.
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prev_r19 : Address; -- GR19 value of the caller's caller.
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top_r3 : Address; -- Caller's initial gr3.
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top_r4 : Address; -- Caller's initial gr4.
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end record;
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-- Provide useful shortcuts for the names
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subtype CFD is Current_Frame_Descriptor;
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subtype PFD is Previous_Frame_Descriptor;
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-- Frames with dynamic stack allocation are handled using the associated
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-- frame pointer, but HP compilers and GCC setup this pointer differently.
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-- HP compilers set it to point at the top (highest address) of the static
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-- part of the frame, whereas GCC sets it to point at the bottom of this
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-- region. We have to fake the unwinder to compensate for this difference,
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-- for which we'll need to access some subprograms unwind descriptors.
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type Bits_2_Value is mod 2 ** 2;
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for Bits_2_Value'Size use 2;
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type Bits_4_Value is mod 2 ** 4;
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for Bits_4_Value'Size use 4;
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type Bits_5_Value is mod 2 ** 5;
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for Bits_5_Value'Size use 5;
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type Bits_27_Value is mod 2 ** 27;
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for Bits_27_Value'Size use 27;
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type Unwind_Descriptor is record
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cannot_unwind : Boolean;
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mcode : Boolean;
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mcode_save_restore : Boolean;
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region_desc : Bits_2_Value;
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reserved0 : Boolean;
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entry_sr : Boolean;
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entry_fr : Bits_4_Value;
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entry_gr : Bits_5_Value;
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args_stored : Boolean;
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variable_frame : Boolean;
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separate_package_body : Boolean;
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frame_extension_mcode : Boolean;
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stack_overflow_check : Boolean;
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two_steps_sp_adjust : Boolean;
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sr4_export : Boolean;
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cxx_info : Boolean;
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cxx_try_catch : Boolean;
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sched_entry_seq : Boolean;
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reserved1 : Boolean;
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save_sp : Boolean;
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save_rp : Boolean;
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save_mrp : Boolean;
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save_r19 : Boolean;
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cleanups : Boolean;
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hpe_interrupt_marker : Boolean;
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hpux_interrupt_marker : Boolean;
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large_frame : Boolean;
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alloca_frame : Boolean;
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reserved2 : Boolean;
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frame_size : Bits_27_Value;
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end record;
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for Unwind_Descriptor'Size use 64;
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for Unwind_Descriptor use record
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cannot_unwind at 0 range 0 .. 0;
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mcode at 0 range 1 .. 1;
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mcode_save_restore at 0 range 2 .. 2;
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region_desc at 0 range 3 .. 4;
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reserved0 at 0 range 5 .. 5;
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entry_sr at 0 range 6 .. 6;
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entry_fr at 0 range 7 .. 10;
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entry_gr at 1 range 3 .. 7;
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args_stored at 2 range 0 .. 0;
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variable_frame at 2 range 1 .. 1;
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separate_package_body at 2 range 2 .. 2;
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frame_extension_mcode at 2 range 3 .. 3;
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stack_overflow_check at 2 range 4 .. 4;
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two_steps_sp_adjust at 2 range 5 .. 5;
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sr4_export at 2 range 6 .. 6;
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cxx_info at 2 range 7 .. 7;
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cxx_try_catch at 3 range 0 .. 0;
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sched_entry_seq at 3 range 1 .. 1;
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reserved1 at 3 range 2 .. 2;
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save_sp at 3 range 3 .. 3;
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save_rp at 3 range 4 .. 4;
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save_mrp at 3 range 5 .. 5;
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save_r19 at 3 range 6 .. 6;
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cleanups at 3 range 7 .. 7;
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hpe_interrupt_marker at 4 range 0 .. 0;
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hpux_interrupt_marker at 4 range 1 .. 1;
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large_frame at 4 range 2 .. 2;
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alloca_frame at 4 range 3 .. 3;
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reserved2 at 4 range 4 .. 4;
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frame_size at 4 range 5 .. 31;
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end record;
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subtype UWD is Unwind_Descriptor;
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type UWD_Ptr is access all UWD;
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function To_UWD_Access is new Ada.Unchecked_Conversion (Address, UWD_Ptr);
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-- The descriptor associated with a given code location is retrieved
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-- using functions imported from the HP library, requiring the definition
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-- of additional structures.
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type Unwind_Table_Region is record
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Table_Start : Address;
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Table_End : Address;
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end record;
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-- An Unwind Table region, which is a memory area containing Unwind
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-- Descriptors.
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subtype UWT is Unwind_Table_Region;
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-- The subprograms imported below are provided by the HP library
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function U_get_unwind_table return UWT;
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pragma Import (C, U_get_unwind_table, "U_get_unwind_table");
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-- Get the unwind table region associated with the current executable.
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-- This function is actually documented as having an argument, but which
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-- is only used for the MPE/iX targets.
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function U_get_shLib_unwind_table (r19 : Address) return UWT;
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pragma Import (C, U_get_shLib_unwind_table, "U_get_shLib_unw_tbl");
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-- Return the unwind table region associated with a possible shared
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-- library, as determined by the provided r19 value.
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function U_get_shLib_text_addr (r19 : Address) return Address;
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pragma Import (C, U_get_shLib_text_addr, "U_get_shLib_text_addr");
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-- Return the address at which the code for a shared library begins, or
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-- -1 if the value provided for r19 does not identify shared library code.
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function U_get_unwind_entry
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(Pc : Address;
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Space : Address;
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Table_Start : Address;
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Table_End : Address) return Address;
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pragma Import (C, U_get_unwind_entry, "U_get_unwind_entry");
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-- Given the bounds of an unwind table, return the address of the
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-- unwind descriptor associated with a code location/space. In the case
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-- of shared library code, the offset from the beginning of the library
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-- is expected as Pc.
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procedure U_init_frame_record (Frame : not null access CFD);
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pragma Import (C, U_init_frame_record, "U_init_frame_record");
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procedure U_prep_frame_rec_for_unwind (Frame : not null access CFD);
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pragma Import (C, U_prep_frame_rec_for_unwind,
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"U_prep_frame_rec_for_unwind");
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-- Fetch the description data of the frame in which these two procedures
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-- are called.
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function U_get_u_rlo
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(Cur : not null access CFD; Prev : not null access PFD) return Integer;
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pragma Import (C, U_get_u_rlo, "U_IS_STUB_OR_CALLX");
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-- From a complete current frame with a return location possibly located
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-- into a linker generated stub, and basic information about the previous
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-- frame, place the first non stub return location into the current frame.
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-- Return -1 if something went wrong during the computation.
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function U_is_shared_pc (rlo : Address; r19 : Address) return Address;
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pragma Import (C, U_is_shared_pc, "U_is_shared_pc");
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-- Return 0 if the provided return location does not correspond to code
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-- in a shared library, or something non null otherwise.
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function U_get_previous_frame_x
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(current_frame : not null access CFD;
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previous_frame : not null access PFD;
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previous_size : Integer) return Integer;
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pragma Import (C, U_get_previous_frame_x, "U_get_previous_frame_x");
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-- Fetch the data describing the "previous" frame relatively to the
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-- "current" one. "previous_size" should be the size of the "previous"
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-- frame descriptor provided.
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--
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-- The library provides a simpler interface without the size parameter
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-- but it is not usable when frames with dynamically allocated space are
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-- on the way.
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procedure Call_Chain
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(Traceback : System.Address;
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Max_Len : Natural;
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Len : out Natural;
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Exclude_Min : System.Address := System.Null_Address;
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Exclude_Max : System.Address := System.Null_Address;
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Skip_Frames : Natural := 1);
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-- Same as the exported version, but takes Traceback as an Address
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------------------
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-- C_Call_Chain --
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------------------
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function C_Call_Chain
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(Traceback : System.Address;
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Max_Len : Natural) return Natural
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is
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Val : Natural;
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begin
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Call_Chain (Traceback, Max_Len, Val);
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return Val;
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end C_Call_Chain;
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----------------
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-- Call_Chain --
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----------------
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procedure Call_Chain
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(Traceback : System.Address;
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Max_Len : Natural;
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Len : out Natural;
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Exclude_Min : System.Address := System.Null_Address;
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Exclude_Max : System.Address := System.Null_Address;
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Skip_Frames : Natural := 1)
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is
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type Tracebacks_Array is array (1 .. Max_Len) of System.Address;
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pragma Suppress_Initialization (Tracebacks_Array);
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-- The code location returned by the unwinder is a return location but
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-- what we need is a call point. Under HP-UX call instructions are 4
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-- bytes long and the return point they specify is 4 bytes beyond the
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-- next instruction because of the delay slot.
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Call_Size : constant := 4;
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DSlot_Size : constant := 4;
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Rlo_Offset : constant := Call_Size + DSlot_Size;
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-- Moreover, the return point is passed via a register which two least
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-- significant bits specify a privilege level that we will have to mask.
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Priv_Mask : constant := 16#00000003#;
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Frame : aliased CFD;
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Code : System.Address;
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J : Natural := 1;
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Pop_Success : Boolean;
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Trace : Tracebacks_Array;
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for Trace'Address use Traceback;
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-- The backtracing process needs a set of subprograms :
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function UWD_For_RLO_Of (Frame : not null access CFD) return UWD_Ptr;
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-- Return an access to the unwind descriptor for the caller of
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-- a given frame, using only the provided return location.
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function UWD_For_Caller_Of (Frame : not null access CFD) return UWD_Ptr;
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-- Return an access to the unwind descriptor for the user code caller
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-- of a given frame, or null if the information is not available.
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function Pop_Frame (Frame : not null access CFD) return Boolean;
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-- Update the provided machine state structure so that it reflects
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-- the state one call frame "above" the initial one.
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--
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-- Return True if the operation has been successful, False otherwise.
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-- Failure typically occurs when the top of the call stack has been
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-- reached.
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function Prepare_For_Unwind_Of
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(Frame : not null access CFD) return Boolean;
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-- Perform the necessary adaptations to the machine state before
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-- calling the unwinder. Currently used for the specific case of
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-- dynamically sized previous frames.
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--
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-- Return True if everything went fine, or False otherwise.
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Program_UWT : constant UWT := U_get_unwind_table;
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---------------
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-- Pop_Frame --
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---------------
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function Pop_Frame (Frame : not null access CFD) return Boolean is
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Up_Frame : aliased PFD;
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State_Ready : Boolean;
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begin
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-- Check/adapt the state before calling the unwinder and return
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-- if anything went wrong.
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State_Ready := Prepare_For_Unwind_Of (Frame);
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if not State_Ready then
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return False;
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end if;
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-- Now, safely call the unwinder and use the results
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if U_get_previous_frame_x (Frame,
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Up_Frame'Access,
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Up_Frame'Size) /= 0
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then
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return False;
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end if;
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-- In case a stub is on the way, the usual previous return location
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-- (the one in prev_rlo) is the one in the stub and the "real" one
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-- is placed in the "current" record, so let's take this one into
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-- account.
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Frame.out_rlo := Frame.cur_rlo;
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Frame.cur_fsz := Up_Frame.prev_fsz;
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Frame.cur_sp := Up_Frame.prev_sp;
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Frame.cur_rls := Up_Frame.prev_rls;
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Frame.cur_rlo := Up_Frame.prev_rlo;
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Frame.cur_dp := Up_Frame.prev_dp;
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Frame.cur_r19 := Up_Frame.prev_r19;
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Frame.top_r3 := Up_Frame.top_r3;
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Frame.top_r4 := Up_Frame.top_r4;
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return True;
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end Pop_Frame;
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---------------------------------
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-- Prepare_State_For_Unwind_Of --
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---------------------------------
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function Prepare_For_Unwind_Of
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(Frame : not null access CFD) return Boolean
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is
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Caller_UWD : UWD_Ptr;
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FP_Adjustment : Integer;
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begin
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-- No need to bother doing anything if the stack is already fully
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-- unwound.
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if Frame.cur_rlo = 0 then
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return False;
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end if;
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-- When ALLOCA_FRAME is set in an unwind descriptor, the unwinder
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-- uses the value provided in current.top_r3 or current.top_r4 as
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-- a frame pointer to compute the size of the frame. What decides
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-- between r3 or r4 is the unwind descriptor LARGE_FRAME bit, with
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-- r4 chosen if the bit is set.
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-- The size computed by the unwinder is STATIC_PART + (SP - FP),
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-- which is correct with HP's frame pointer convention, but not
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-- with GCC's one since we end up with the static part accounted
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-- for twice.
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-- We have to compute r4 when it is required because the unwinder
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-- has looked for it at a place where it was not if we went through
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-- GCC frames.
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-- The size of the static part of a frame can be found in the
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-- associated unwind descriptor.
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Caller_UWD := UWD_For_Caller_Of (Frame);
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-- If we cannot get it, we are unable to compute the potentially
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-- necessary adjustments. We'd better not try to go on then.
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if Caller_UWD = null then
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return False;
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end if;
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-- If the caller frame is a GCC one, r3 is its frame pointer and
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-- points to the bottom of the frame. The value to provide for r4
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-- can then be computed directly from the one of r3, compensating
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-- for the static part of the frame.
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-- If the caller frame is an HP one, r3 is used to locate the
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-- previous frame marker, that is it also points to the bottom of
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-- the frame (this is why r3 cannot be used as the frame pointer in
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-- the HP sense for large frames). The value to provide for r4 can
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-- then also be computed from the one of r3 with the compensation
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-- for the static part of the frame.
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FP_Adjustment := Integer (Caller_UWD.frame_size * 8);
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Frame.top_r4 := Address (Integer (Frame.top_r3) + FP_Adjustment);
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return True;
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end Prepare_For_Unwind_Of;
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-----------------------
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-- UWD_For_Caller_Of --
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-----------------------
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function UWD_For_Caller_Of (Frame : not null access CFD) return UWD_Ptr
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is
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UWD_Access : UWD_Ptr;
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begin
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-- First try the most direct path, using the return location data
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-- associated with the frame.
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UWD_Access := UWD_For_RLO_Of (Frame);
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if UWD_Access /= null then
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return UWD_Access;
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end if;
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-- If we did not get a result, we might face an in-stub return
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-- address. In this case U_get_previous_frame can tell us what the
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-- first not-in-stub return point is. We cannot call it directly,
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-- though, because we haven't computed the potentially necessary
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-- frame pointer adjustments, which might lead to SEGV in some
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-- circumstances. Instead, we directly call the libcl routine which
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-- is called by U_get_previous_frame and which only requires few
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-- information. Take care, however, that the information is provided
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-- in the "current" argument, so we need to work on a copy to avoid
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-- disturbing our caller.
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declare
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U_Current : aliased CFD := Frame.all;
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U_Previous : aliased PFD;
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begin
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U_Previous.prev_dp := U_Current.cur_dp;
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U_Previous.prev_rls := U_Current.cur_rls;
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U_Previous.prev_sp := U_Current.cur_sp - U_Current.cur_fsz;
|
|
|
|
if U_get_u_rlo (U_Current'Access, U_Previous'Access) /= -1 then
|
|
UWD_Access := UWD_For_RLO_Of (U_Current'Access);
|
|
end if;
|
|
end;
|
|
|
|
return UWD_Access;
|
|
end UWD_For_Caller_Of;
|
|
|
|
--------------------
|
|
-- UWD_For_RLO_Of --
|
|
--------------------
|
|
|
|
function UWD_For_RLO_Of (Frame : not null access CFD) return UWD_Ptr
|
|
is
|
|
UWD_Address : Address;
|
|
|
|
-- The addresses returned by the library point to full descriptors
|
|
-- including the frame information bits but also the applicable PC
|
|
-- range. We need to account for this.
|
|
|
|
Frame_Info_Offset : constant := 8;
|
|
|
|
begin
|
|
-- First try to locate the descriptor in the program's unwind table
|
|
|
|
UWD_Address := U_get_unwind_entry (Frame.cur_rlo,
|
|
Frame.cur_rls,
|
|
Program_UWT.Table_Start,
|
|
Program_UWT.Table_End);
|
|
|
|
-- If we did not get it, we might have a frame from code in a
|
|
-- stub or shared library. For code in stub we would have to
|
|
-- compute the first non-stub return location but this is not
|
|
-- the role of this subprogram, so let's just try to see if we
|
|
-- can get a result from the tables in shared libraries.
|
|
|
|
if UWD_Address = -1
|
|
and then U_is_shared_pc (Frame.cur_rlo, Frame.cur_r19) /= 0
|
|
then
|
|
declare
|
|
Shlib_UWT : constant UWT :=
|
|
U_get_shLib_unwind_table (Frame.cur_r19);
|
|
Shlib_Start : constant Address :=
|
|
U_get_shLib_text_addr (Frame.cur_r19);
|
|
Rlo_Offset : constant Address :=
|
|
Frame.cur_rlo - Shlib_Start;
|
|
begin
|
|
UWD_Address := U_get_unwind_entry (Rlo_Offset,
|
|
Frame.cur_rls,
|
|
Shlib_UWT.Table_Start,
|
|
Shlib_UWT.Table_End);
|
|
end;
|
|
end if;
|
|
|
|
if UWD_Address /= -1 then
|
|
return To_UWD_Access (UWD_Address + Frame_Info_Offset);
|
|
else
|
|
return null;
|
|
end if;
|
|
end UWD_For_RLO_Of;
|
|
|
|
-- Start of processing for Call_Chain
|
|
|
|
begin
|
|
-- Fetch the state for this subprogram's frame and pop it so that we
|
|
-- start with an initial out_rlo "here".
|
|
|
|
U_init_frame_record (Frame'Access);
|
|
Frame.top_sr0 := 0;
|
|
Frame.top_sr4 := 0;
|
|
|
|
U_prep_frame_rec_for_unwind (Frame'Access);
|
|
|
|
Pop_Success := Pop_Frame (Frame'Access);
|
|
|
|
-- Skip the requested number of frames
|
|
|
|
for I in 1 .. Skip_Frames loop
|
|
Pop_Success := Pop_Frame (Frame'Access);
|
|
end loop;
|
|
|
|
-- Loop popping frames and storing locations until either a problem
|
|
-- occurs, or the top of the call chain is reached, or the provided
|
|
-- array is full.
|
|
|
|
loop
|
|
-- We have to test some conditions against the return location
|
|
-- as it is returned, so get it as is first.
|
|
|
|
Code := Frame.out_rlo;
|
|
|
|
exit when not Pop_Success or else Code = 0 or else J = Max_Len + 1;
|
|
|
|
-- Compute the call point from the retrieved return location :
|
|
-- Mask the privilege bits and account for the delta between the
|
|
-- call site and the return point.
|
|
|
|
Code := (Code and not Priv_Mask) - Rlo_Offset;
|
|
|
|
if Code < Exclude_Min or else Code > Exclude_Max then
|
|
Trace (J) := Code;
|
|
J := J + 1;
|
|
end if;
|
|
|
|
Pop_Success := Pop_Frame (Frame'Access);
|
|
end loop;
|
|
|
|
Len := J - 1;
|
|
end Call_Chain;
|
|
|
|
procedure Call_Chain
|
|
(Traceback : in out System.Traceback_Entries.Tracebacks_Array;
|
|
Max_Len : Natural;
|
|
Len : out Natural;
|
|
Exclude_Min : System.Address := System.Null_Address;
|
|
Exclude_Max : System.Address := System.Null_Address;
|
|
Skip_Frames : Natural := 1)
|
|
is
|
|
begin
|
|
Call_Chain
|
|
(Traceback'Address, Max_Len, Len,
|
|
Exclude_Min, Exclude_Max,
|
|
|
|
-- Skip one extra frame to skip the other Call_Chain entry as well
|
|
|
|
Skip_Frames => Skip_Frames + 1);
|
|
end Call_Chain;
|
|
|
|
end System.Traceback;
|