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/* EH stuff
Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
This file is part of GNU CC.
This program 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 2, or (at your option) any
later version.
This program 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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* This file contains the structures required for the language
independent exception handling model. Both the static compiler and
the runtime library share this file. */
/* The runtime flag flag_new_exceptions is used to determine whether the
compiler supports the new runtime typechecking mechanism or not. Under
the new model, runtime info is contained in the exception table, and
the __throw() library routine determines which handler to call based
on the results of a call to a matching function provided by the expcetion
thrower. Otherwise the old scheme of calling any handler which matches
an exception range is used, and the handler is responsible for all
checking of runtime conditions. If the handler wasn't suppose to
get the exception, it performs a re-throw. */
/* The handler_label field MUST be the first field in this structure. The
__throw() library routine expects uses __eh_stub() from except.c, which
simply dereferences the context pointer to get the handler.
The routine get_dynamic_handler_chain() also has a dependancy on
the location of 'dynamic_handler_chain'. If its location is changed,
that routine must be modified as well. */
#ifndef EH_ALLOC_SIZE
/* 192 bytes means the entire eh_context plus malloc overhead fits in 256
bytes (assuming 8 byte pointers). 192 bytes gives an eh_info and object
size limit of 96 bytes. This should be sufficient for throwing bad_alloc. */
#define EH_ALLOC_SIZE 192
#endif
#ifndef EH_ALLOC_ALIGN
/* We can't use BIGGEST_ALIGNMENT, because on some systems, that expands to
a check on a compile time switch like
'target_flags & MASK_ALIGN_DOUBLE ? 64 : 32'. There's no macro for
'largest alignment for any code this compiler can build for', which is
really what is needed. */
#define EH_ALLOC_ALIGN 16
#endif
struct eh_context
{
void *handler_label;
void **dynamic_handler_chain;
/* This is language dependent part of the eh context. */
void *info;
/* This is used to remember where we threw for re-throws */
void *table_index; /* address of exception table entry to rethrow from */
/* emergency fallback space, if malloc fails during handling */
char alloc_buffer[EH_ALLOC_SIZE]
__attribute__((__aligned__(EH_ALLOC_ALIGN)));
unsigned alloc_mask;
};
#ifndef EH_TABLE_LOOKUP
typedef struct old_exception_table
{
void *start_region;
void *end_region;
void *exception_handler;
} old_exception_table;
typedef struct exception_table
{
void *start_region;
void *end_region;
void *exception_handler;
void *match_info; /* runtime type info */
} exception_table;
/* The language identifying portion of an exception table */
typedef struct exception_lang_info
{
short language;
short version;
} exception_lang_info;
/* This value in the first field of the exception descriptor
identifies the descriptor as the new model format. This value would never
be present in this location under the old model */
#define NEW_EH_RUNTIME ((void *) -2)
/* Each function has an exception_descriptor which contains the
language info, and a table of exception ranges and handlers */
typedef struct exception_descriptor
{
void *runtime_id_field;
exception_lang_info lang;
exception_table table[1];
} exception_descriptor;
struct __eh_info; /* forward declaration */
/* A pointer to a matching function is initialized at runtime by the
specific language if run-time exceptions are supported.
The function takes 3 parameters
1 - runtime exception that has been thrown info. (__eh_info *)
2 - Match info pointer from the region being considered (void *)
3 - exception table region is in (exception descriptor *)
*/
typedef void * (*__eh_matcher) PARAMS ((struct __eh_info *, void *,
struct exception_descriptor *));
/* This value is to be checked as a 'match all' case in the runtime field. */
#define CATCH_ALL_TYPE ((void *) -1)
/* This is the runtime exception information. This forms the minimum required
information for an exception info pointer in an eh_context structure. */
typedef struct __eh_info
{
__eh_matcher match_function;
short language;
short version;
} __eh_info;
/* Convienient language codes for ID the originating language. Similar
to the codes in dwarf2.h. */
enum exception_source_language
{
EH_LANG_C89 = 0x0001,
EH_LANG_C = 0x0002,
EH_LANG_Ada83 = 0x0003,
EH_LANG_C_plus_plus = 0x0004,
EH_LANG_Cobol74 = 0x0005,
EH_LANG_Cobol85 = 0x0006,
EH_LANG_Fortran77 = 0x0007,
EH_LANG_Fortran90 = 0x0008,
EH_LANG_Pascal83 = 0x0009,
EH_LANG_Modula2 = 0x000a,
EH_LANG_Java = 0x000b,
EH_LANG_Mips_Assembler = 0x8001
};
#endif /* EH_TABLE_LOOKUP */
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