gcc/eh-common.h

   1 /* Copyright (C) 1997 Free Software Foundation, Inc.
   2    This file is part of GNU CC.  */
   3
   4 /* This file contains the structures required for the language
   5    independant exception handling model. Both the static compiler and
   6    the runtime library share this file. */
   7
   8 /* The runtime flag flag_new_exceptions is used to determine whether the
   9    compiler supports the new runtime typechecking mechanism or not. Under
  10    the new model, runtime info is contained in the exception table, and
  11    the __throw() library routine determines which handler to call based
  12    on the results of a call to a matching function provided by the expcetion
  13    thrower.  Otherwise the old scheme of calling any handler which matches
  14    an exception range is used, and the handler is responsible for all
  15    checking of runtime conditions. If the handler wasn't suppose to
  16    get the exception, it performs a re-throw. */
  17
  18 #include "gansidecl.h"
  19
  20
  21 /* The handler_label field MUST be the first field in this structure. The
  22    __throw()  library routine expects uses __eh_stub() from except.c, which
  23    simply dereferences the context pointer to get the handler */
  24
  25 struct eh_context
  26 {
  27   void *handler_label;
  28   void **dynamic_handler_chain;
  29   /* This is language dependent part of the eh context. */
  30   void *info;
  31 };
  32
  33 #ifndef EH_TABLE_LOOKUP
  34
  35 typedef struct old_exception_table
  36 {
  37   void *start_region;
  38   void *end_region;
  39   void *exception_handler;
  40 } old_exception_table;
  41
  42 typedef struct exception_table
  43 {
  44   void *start_region;
  45   void *end_region;
  46   void *exception_handler;
  47   void *match_info;              /* runtime type info */
  48 } exception_table;
  49
  50
  51 /* The language identifying portion of an exception table */
  52
  53 typedef struct exception_lang_info
  54 {
  55   short language;
  56   short version;
  57 } exception_lang_info;
  58
  59 /* This value in the first field of the exception descriptor
  60    identifies the descriptor as the new model format. This value would never
  61    be present in this location under the old model */
  62
  63 #define NEW_EH_RUNTIME  ((void *) -2)
  64
  65 /* Each function has an exception_descriptor which contains the
  66    language info, and a table of exception ranges and handlers */
  67
  68 typedef struct exception_descriptor
  69 {
  70   void *runtime_id_field;
  71   exception_lang_info lang;
  72   exception_table table[1];
  73 } exception_descriptor;
  74
  75
  76 /* A pointer to a matching function is initialized at runtime by the
  77    specific language if run-time exceptions are supported.
  78    The function takes 3 parameters
  79     1 - runtime exception that has been thrown info. (__eh_info *)
  80     2 - Match info pointer from the region being considered (void *)
  81     3 - exception table region is in (exception descriptor *)
  82 */
  83
  84 typedef void * (*__eh_matcher)          PROTO ((void *, void *, void *));
  85
  86 /* This is the runtime exception information. This forms the minimum required
  87    information for an exception info pointer in an eh_context structure. */
  88
  89 typedef struct __eh_info
  90 {
  91   __eh_matcher match_function;
  92   void *coerced_value;
  93   short language;
  94   short version;
  95 } __eh_info;
  96
  97 /* Convienient language codes for ID the originating language. Similar
  98    to the codes in dwarf2.h. */
  99
 100 enum exception_source_language
 101   {
 102     EH_LANG_C89 = 0x0001,
 103     EH_LANG_C = 0x0002,
 104     EH_LANG_Ada83 = 0x0003,
 105     EH_LANG_C_plus_plus = 0x0004,
 106     EH_LANG_Cobol74 = 0x0005,
 107     EH_LANG_Cobol85 = 0x0006,
 108     EH_LANG_Fortran77 = 0x0007,
 109     EH_LANG_Fortran90 = 0x0008,
 110     EH_LANG_Pascal83 = 0x0009,
 111     EH_LANG_Modula2 = 0x000a,
 112     EH_LANG_Java = 0x000b,
 113     EH_LANG_Mips_Assembler = 0x8001
 114   };
 115
 116 #endif  /* EH_TABLE_LOOKUP */
 117
 118