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// Exception handling and frame unwind runtime interface routines.
// Copyright (C) 2011-2021 Free Software Foundation, Inc.
// GCC is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3, or (at your option) any later
// version.
// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
// 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
// <>.
// extern(C) interface for the generic unwinder library.
// This corresponds to unwind-generic.h
module gcc.unwind.generic;
import gcc.config;
static if (!GNU_ARM_EABI_Unwinder):
import gcc.builtins;
// This is derived from the C++ ABI for IA-64. Where we diverge
// for cross-architecture compatibility are noted with "@@@".
extern (C):
// Placed outside @nogc in order to not constrain what the callback does.
// ??? Does this really need to be extern(C) alias?
extern(C) alias _Unwind_Exception_Cleanup_Fn
= void function(_Unwind_Reason_Code, _Unwind_Exception*);
extern(C) alias _Unwind_Stop_Fn
= _Unwind_Reason_Code function(int, _Unwind_Action,
_Unwind_Context*, void*);
extern(C) alias _Unwind_Trace_Fn
= _Unwind_Reason_Code function(_Unwind_Context*, void*);
// The personality routine is the function in the C++ (or other language)
// runtime library which serves as an interface between the system unwind
// library and language-specific exception handling semantics. It is
// specific to the code fragment described by an unwind info block, and
// it is always referenced via the pointer in the unwind info block, and
// hence it has no ABI-specified name.
// Note that this implies that two different C++ implementations can
// use different names, and have different contents in the language
// specific data area. Moreover, that the language specific data
// area contains no version info because name of the function invoked
// provides more effective versioning by detecting at link time the
// lack of code to handle the different data format.
extern(C) alias _Unwind_Personality_Fn
= _Unwind_Reason_Code function(int, _Unwind_Action,
// Level 1: Base ABI
// @@@ The IA-64 ABI uses uint64 throughout.
// Most places this is inefficient for 32-bit and smaller machines.
alias _Unwind_Word = __builtin_unwind_uint;
alias _Unwind_Sword = __builtin_unwind_int;
version (IA64)
version (HPUX)
alias _Unwind_Ptr = __builtin_machine_uint;
alias _Unwind_Ptr = __builtin_pointer_uint;
alias _Unwind_Ptr = __builtin_pointer_uint;
alias _Unwind_Internal_Ptr = __builtin_pointer_uint;
// @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
// consumer of an exception. We'll go along with this for now even on
// 32-bit machines. We'll need to provide some other option for
// 16-bit machines and for machines with > 8 bits per byte.
alias _Unwind_Exception_Class = ulong;
// The unwind interface uses reason codes in several contexts to
// identify the reasons for failures or other actions.
alias _Unwind_Reason_Code = uint;
enum : _Unwind_Reason_Code
// The unwind interface uses a pointer to an exception header object
// as its representation of an exception being thrown. In general, the
// full representation of an exception object is language- and
// implementation-specific, but it will be prefixed by a header
// understood by the unwind interface.
// @@@ The IA-64 ABI says that this structure must be double-word aligned.
// Taking that literally does not make much sense generically. Instead we
// provide the maximum alignment required by any type for the machine.
version (ARM) private enum __aligned__ = 8;
else version (AArch64) private enum __aligned__ = 16;
else version (HPPA) private enum __aligned__ = 8;
else version (HPPA64) private enum __aligned__ = 16;
else version (MIPS_N32) private enum __aligned__ = 16;
else version (MIPS_N64) private enum __aligned__ = 16;
else version (MIPS32) private enum __aligned__ = 8;
else version (MIPS64) private enum __aligned__ = 8;
else version (PPC) private enum __aligned__ = 16;
else version (PPC64) private enum __aligned__ = 16;
else version (RISCV32) private enum __aligned__ = 16;
else version (RISCV64) private enum __aligned__ = 16;
else version (S390) private enum __aligned__ = 8;
else version (SPARC) private enum __aligned__ = 8;
else version (SPARC64) private enum __aligned__ = 16;
else version (SystemZ) private enum __aligned__ = 8;
else version (X86) private enum __aligned__ = 16;
else version (X86_64) private enum __aligned__ = 16;
else static assert( false, "Platform not supported.");
align(__aligned__) struct _Unwind_Exception
_Unwind_Exception_Class exception_class;
_Unwind_Exception_Cleanup_Fn exception_cleanup;
_Unwind_Word private_1;
_Unwind_Word private_2;
// The ACTIONS argument to the personality routine is a bitwise OR of one
// or more of the following constants.
alias _Unwind_Action = int;
enum : _Unwind_Action
// This is an opaque type used to refer to a system-specific data
// structure used by the system unwinder. This context is created and
// destroyed by the system, and passed to the personality routine
// during unwinding.
struct _Unwind_Context;
// Raise an exception, passing along the given exception object.
_Unwind_Reason_Code _Unwind_RaiseException(_Unwind_Exception*);
// Raise an exception for forced unwinding.
_Unwind_Reason_Code _Unwind_ForcedUnwind(_Unwind_Exception*, _Unwind_Stop_Fn, void*);
// Helper to invoke the exception_cleanup routine.
void _Unwind_DeleteException(_Unwind_Exception*);
// Resume propagation of an existing exception. This is used after
// e.g. executing cleanup code, and not to implement rethrowing.
void _Unwind_Resume(_Unwind_Exception*);
// @@@ Resume propagation of an FORCE_UNWIND exception, or to rethrow
// a normal exception that was handled.
_Unwind_Reason_Code _Unwind_Resume_or_Rethrow(_Unwind_Exception*);
// @@@ Use unwind data to perform a stack backtrace. The trace callback
// is called for every stack frame in the call chain, but no cleanup
// actions are performed.
_Unwind_Reason_Code _Unwind_Backtrace(_Unwind_Trace_Fn, void*);
// These functions are used for communicating information about the unwind
// context (i.e. the unwind descriptors and the user register state) between
// the unwind library and the personality routine and landing pad. Only
// selected registers may be manipulated.
_Unwind_Word _Unwind_GetGR(_Unwind_Context*, int);
void _Unwind_SetGR(_Unwind_Context*, int, _Unwind_Word);
_Unwind_Ptr _Unwind_GetIP(_Unwind_Context*);
_Unwind_Ptr _Unwind_GetIPInfo(_Unwind_Context*, int*);
void _Unwind_SetIP(_Unwind_Context*, _Unwind_Ptr);
// @@@ Retrieve the CFA of the given context.
_Unwind_Word _Unwind_GetCFA(_Unwind_Context*);
void* _Unwind_GetLanguageSpecificData(_Unwind_Context*);
_Unwind_Ptr _Unwind_GetRegionStart(_Unwind_Context*);
// @@@ The following alternate entry points are for setjmp/longjmp
// based unwinding.
struct SjLj_Function_Context;
extern void _Unwind_SjLj_Register(SjLj_Function_Context*);
extern void _Unwind_SjLj_Unregister(SjLj_Function_Context*);
_Unwind_Reason_Code _Unwind_SjLj_RaiseException(_Unwind_Exception*);
_Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind(_Unwind_Exception*, _Unwind_Stop_Fn, void*);
void _Unwind_SjLj_Resume(_Unwind_Exception*);
_Unwind_Reason_Code _Unwind_SjLj_Resume_or_Rethrow(_Unwind_Exception*);
// @@@ The following provide access to the base addresses for text
// and data-relative addressing in the LDSA. In order to stay link
// compatible with the standard ABI for IA-64, we inline these.
version (IA64)
_Unwind_Ptr _Unwind_GetDataRelBase(_Unwind_Context* _C)
// The GP is stored in R1.
return _Unwind_GetGR(_C, 1);
_Unwind_Ptr _Unwind_GetTextRelBase(_Unwind_Context*)
return 0;
// @@@ Retrieve the Backing Store Pointer of the given context.
_Unwind_Word _Unwind_GetBSP(_Unwind_Context*);
_Unwind_Ptr _Unwind_GetDataRelBase(_Unwind_Context*);
_Unwind_Ptr _Unwind_GetTextRelBase(_Unwind_Context*);
// @@@ Given an address, return the entry point of the function that
// contains it.
extern void* _Unwind_FindEnclosingFunction(void* pc);
// leb128 type numbers have a potentially unlimited size.
// The target of the following definitions of _sleb128_t and _uleb128_t
// is to have efficient data types large enough to hold the leb128 type
// numbers used in the unwind code.
// Mostly these types will simply be defined to long and unsigned long
// except when a unsigned long data type on the target machine is not
// capable of storing a pointer.
static if (__builtin_clong.sizeof >= (void*).sizeof)
alias _sleb128_t = __builtin_clong;
alias _uleb128_t = __builtin_culong;
else static if (long.sizeof >= (void*).sizeof)
alias _sleb128_t = long;
alias _uleb128_t = ulong;
static assert(false, "What type shall we use for _sleb128_t?");
version (GNU_SEH_Exceptions)
// We're lazy, exact definition in MinGW/winnt.h
extern(C) EXCEPTION_DISPOSITION _GCC_specific_handler(void*, void*, void*, void*,