diff options
Diffstat (limited to 'gcc/ada/libgnat/s-excmac-gcc.ads')
| -rw-r--r-- | gcc/ada/libgnat/s-excmac-gcc.ads | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/gcc/ada/libgnat/s-excmac-gcc.ads b/gcc/ada/libgnat/s-excmac-gcc.ads new file mode 100644 index 00000000000..dabf8b68b74 --- /dev/null +++ b/gcc/ada/libgnat/s-excmac-gcc.ads @@ -0,0 +1,185 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S Y S T E M . E X C E P T I O N S . M A C H I N E -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 2013-2017, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. -- +-- -- +-- As a special exception under Section 7 of GPL version 3, you are granted -- +-- additional permissions described in the GCC Runtime Library Exception, -- +-- version 3.1, as published by the Free Software Foundation. -- +-- -- +-- You should have received a copy of the GNU General Public License and -- +-- a copy of the GCC Runtime Library Exception along with this program; -- +-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- +-- <http://www.gnu.org/licenses/>. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +-- Declaration of the machine exception and some associated facilities. The +-- machine exception is the object that is propagated by low level routines +-- and that contains the Ada exception occurrence. + +-- This is the version using the GCC EH mechanism + +with Ada.Unchecked_Conversion; +with Ada.Exceptions; + +package System.Exceptions.Machine is + pragma Preelaborate; + + ------------------------------------------------ + -- Entities to interface with the GCC runtime -- + ------------------------------------------------ + + -- These come from "C++ ABI for Itanium: Exception handling", which is + -- the reference for GCC. + + -- Return codes from the GCC runtime functions used to propagate + -- an exception. + + type Unwind_Reason_Code is + (URC_NO_REASON, + URC_FOREIGN_EXCEPTION_CAUGHT, + URC_PHASE2_ERROR, + URC_PHASE1_ERROR, + URC_NORMAL_STOP, + URC_END_OF_STACK, + URC_HANDLER_FOUND, + URC_INSTALL_CONTEXT, + URC_CONTINUE_UNWIND); + + pragma Unreferenced + (URC_NO_REASON, + URC_FOREIGN_EXCEPTION_CAUGHT, + URC_PHASE2_ERROR, + URC_PHASE1_ERROR, + URC_NORMAL_STOP, + URC_END_OF_STACK, + URC_HANDLER_FOUND, + URC_INSTALL_CONTEXT, + URC_CONTINUE_UNWIND); + + pragma Convention (C, Unwind_Reason_Code); + + -- Phase identifiers + + type Unwind_Action is new Integer; + pragma Convention (C, Unwind_Action); + + UA_SEARCH_PHASE : constant Unwind_Action := 1; + UA_CLEANUP_PHASE : constant Unwind_Action := 2; + UA_HANDLER_FRAME : constant Unwind_Action := 4; + UA_FORCE_UNWIND : constant Unwind_Action := 8; + UA_END_OF_STACK : constant Unwind_Action := 16; -- GCC extension + + pragma Unreferenced + (UA_SEARCH_PHASE, + UA_CLEANUP_PHASE, + UA_HANDLER_FRAME, + UA_FORCE_UNWIND, + UA_END_OF_STACK); + + -- Mandatory common header for any exception object handled by the + -- GCC unwinding runtime. + + type Exception_Class is mod 2 ** 64; + + GNAT_Exception_Class : constant Exception_Class := 16#474e552d41646100#; + -- "GNU-Ada\0" + + type Unwind_Word is mod 2 ** System.Word_Size; + for Unwind_Word'Size use System.Word_Size; + -- Map the corresponding C type used in Unwind_Exception below + + type Unwind_Exception is record + Class : Exception_Class; + Cleanup : System.Address; + Private1 : Unwind_Word; + Private2 : Unwind_Word; + + -- Usual exception structure has only two private fields, but the SEH + -- one has six. To avoid making this file more complex, we use six + -- fields on all platforms, wasting a few bytes on some. + + Private3 : Unwind_Word; + Private4 : Unwind_Word; + Private5 : Unwind_Word; + Private6 : Unwind_Word; + end record; + pragma Convention (C, Unwind_Exception); + -- Map the GCC struct used for exception handling + + for Unwind_Exception'Alignment use Standard'Maximum_Alignment; + -- The C++ ABI mandates the common exception header to be at least + -- doubleword aligned, and the libGCC implementation actually makes it + -- maximally aligned (see unwind.h). See additional comments on the + -- alignment below. + + -- There is a subtle issue with the common header alignment, since the C + -- version is aligned on BIGGEST_ALIGNMENT, the Ada version is aligned on + -- Standard'Maximum_Alignment, and those two values don't quite represent + -- the same concepts and so may be decoupled someday. One typical reason + -- is that BIGGEST_ALIGNMENT may be larger than what the underlying system + -- allocator guarantees, and there are extra costs involved in allocating + -- objects aligned to such factors. + + -- To deal with the potential alignment differences between the C and Ada + -- representations, the Ada part of the whole structure is only accessed + -- by the personality routine through accessors. Ada specific fields are + -- thus always accessed through consistent layout, and we expect the + -- actual alignment to always be large enough to avoid traps from the C + -- accesses to the common header. Besides, accessors alleviate the need + -- for a C struct whole counterpart, both painful and error-prone to + -- maintain anyway. + + type GCC_Exception_Access is access all Unwind_Exception; + -- Pointer to a GCC exception + + procedure Unwind_DeleteException (Excp : not null GCC_Exception_Access); + pragma Import (C, Unwind_DeleteException, "_Unwind_DeleteException"); + -- Procedure to free any GCC exception + + -------------------------------------------------------------- + -- GNAT Specific Entities To Deal With The GCC EH Circuitry -- + -------------------------------------------------------------- + + -- A GNAT exception object to be dealt with by the personality routine + -- called by the GCC unwinding runtime. + + type GNAT_GCC_Exception is record + Header : Unwind_Exception; + -- ABI Exception header first + + Occurrence : aliased Ada.Exceptions.Exception_Occurrence; + -- The Ada occurrence + end record; + + pragma Convention (C, GNAT_GCC_Exception); + + type GNAT_GCC_Exception_Access is access all GNAT_GCC_Exception; + + function To_GCC_Exception is new + Ada.Unchecked_Conversion (System.Address, GCC_Exception_Access); + + function To_GNAT_GCC_Exception is new + Ada.Unchecked_Conversion + (GCC_Exception_Access, GNAT_GCC_Exception_Access); + + function New_Occurrence return GNAT_GCC_Exception_Access; + -- Allocate and initialize a machine occurrence + +end System.Exceptions.Machine; |