1 /*
2  * msvcrt C++ exception handling
3  *
4  * Copyright 2002 Alexandre Julliard
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
19  */
20 
21 #ifndef __MSVCRT_CPPEXCEPT_H
22 #define __MSVCRT_CPPEXCEPT_H
23 
24 #define CXX_FRAME_MAGIC_VC6 0x19930520
25 #define CXX_FRAME_MAGIC_VC7 0x19930521
26 #define CXX_FRAME_MAGIC_VC8 0x19930522
27 #define CXX_EXCEPTION       0xe06d7363
28 
29 /* Macros to define assembler functions somewhat portably */
30 
31 #define EH_NONCONTINUABLE   0x01
32 #define EH_UNWINDING        0x02
33 #define EH_EXIT_UNWIND      0x04
34 #define EH_STACK_INVALID    0x08
35 #define EH_NESTED_CALL      0x10
36 
37 typedef void (*vtable_ptr)();
38 
39 /* type_info object, see cpp.c for inplementation */
40 typedef struct __type_info
41 {
42   const vtable_ptr *vtable;
43   char              *name;        /* Unmangled name, allocated lazily */
44   char               mangled[32]; /* Variable length, but we declare it large enough for static RTTI */
45 } type_info;
46 
47 /* exception object */
48 typedef struct __exception
49 {
50   const vtable_ptr *vtable;
51   char             *name;    /* Name of this exception, always a new copy for each object */
52   int               do_free; /* Whether to free 'name' in our dtor */
53 } exception;
54 
55 /* the exception frame used by CxxFrameHandler */
56 typedef struct __cxx_exception_frame
57 {
58     EXCEPTION_REGISTRATION_RECORD  frame;    /* the standard exception frame */
59     int                            trylevel;
60     DWORD                          ebp;
61 } cxx_exception_frame;
62 
63 /* info about a single catch {} block */
64 typedef struct __catchblock_info
65 {
66     UINT             flags;         /* flags (see below) */
67     const type_info *type_info;     /* C++ type caught by this block */
68     int              offset;        /* stack offset to copy exception object to */
69     void           (*handler)(void);/* catch block handler code */
70 } catchblock_info;
71 #define TYPE_FLAG_CONST      1
72 #define TYPE_FLAG_VOLATILE   2
73 #define TYPE_FLAG_REFERENCE  8
74 
75 /* info about a single try {} block */
76 typedef struct __tryblock_info
77 {
78     int                    start_level;      /* start trylevel of that block */
79     int                    end_level;        /* end trylevel of that block */
80     int                    catch_level;      /* initial trylevel of the catch block */
81     int                    catchblock_count; /* count of catch blocks in array */
82     const catchblock_info *catchblock;       /* array of catch blocks */
83 } tryblock_info;
84 
85 /* info about the unwind handler for a given trylevel */
86 typedef struct __unwind_info
87 {
88     int    prev;          /* prev trylevel unwind handler, to run after this one */
89     void (*handler)(void);/* unwind handler */
90 } unwind_info;
91 
92 /* descriptor of all try blocks of a given function */
93 typedef struct __cxx_function_descr
94 {
95     UINT                 magic;          /* must be CXX_FRAME_MAGIC */
96     UINT                 unwind_count;   /* number of unwind handlers */
97     const unwind_info   *unwind_table;   /* array of unwind handlers */
98     UINT                 tryblock_count; /* number of try blocks */
99     const tryblock_info *tryblock;       /* array of try blocks */
100     UINT                 ipmap_count;
101     const void          *ipmap;
102     const void          *expect_list;    /* expected exceptions list when magic >= VC7 */
103     UINT                 flags;          /* flags when magic >= VC8 */
104 } cxx_function_descr;
105 
106 #define FUNC_DESCR_SYNCHRONOUS  1        /* synchronous exceptions only (built with /EHs) */
107 
108 typedef void (*cxx_copy_ctor)(void);
109 
110 /* offsets for computing the this pointer */
111 typedef struct
112 {
113     int         this_offset;   /* offset of base class this pointer from start of object */
114     int         vbase_descr;   /* offset of virtual base class descriptor */
115     int         vbase_offset;  /* offset of this pointer offset in virtual base class descriptor */
116 } this_ptr_offsets;
117 
118 /* complete information about a C++ type */
119 typedef struct __cxx_type_info
120 {
121     UINT             flags;        /* flags (see CLASS_* flags below) */
122     const type_info *type_info;    /* C++ type info */
123     this_ptr_offsets offsets;      /* offsets for computing the this pointer */
124     unsigned int     size;         /* object size */
125     cxx_copy_ctor    copy_ctor;    /* copy constructor */
126 } cxx_type_info;
127 #define CLASS_IS_SIMPLE_TYPE          1
128 #define CLASS_HAS_VIRTUAL_BASE_CLASS  4
129 
130 /* table of C++ types that apply for a given object */
131 typedef struct __cxx_type_info_table
132 {
133     UINT                 count;     /* number of types */
134     const cxx_type_info *info[3];   /* variable length, we declare it large enough for static RTTI */
135 } cxx_type_info_table;
136 
137 typedef DWORD (*cxx_exc_custom_handler)( PEXCEPTION_RECORD, cxx_exception_frame*,
138                                          PCONTEXT, EXCEPTION_REGISTRATION_RECORD**,
139                                          const cxx_function_descr*, int nested_trylevel,
140                                          EXCEPTION_REGISTRATION_RECORD *nested_frame, DWORD unknown3 );
141 
142 /* type information for an exception object */
143 typedef struct __cxx_exception_type
144 {
145     UINT                       flags;            /* TYPE_FLAG flags */
146     void                     (*destructor)(void);/* exception object destructor */
147     cxx_exc_custom_handler     custom_handler;   /* custom handler for this exception */
148     const cxx_type_info_table *type_info_table;  /* list of types for this exception object */
149 } cxx_exception_type;
150 
151 void WINAPI _CxxThrowException(exception*,const cxx_exception_type*);
152 int CDECL _XcptFilter(NTSTATUS, PEXCEPTION_POINTERS);
153 int CDECL __CppXcptFilter(NTSTATUS, PEXCEPTION_POINTERS);
154 
155 static inline const char *dbgstr_type_info( const type_info *info )
156 {
157     if (!info) return "{}";
158     return wine_dbg_sprintf( "{vtable=%p name=%s (%s)}",
159                              info->vtable, info->mangled, info->name ? info->name : "" );
160 }
161 
162 /* compute the this pointer for a base class of a given type */
163 static inline void *get_this_pointer( const this_ptr_offsets *off, void *object )
164 {
165     if (!object) return NULL;
166 
167     if (off->vbase_descr >= 0)
168     {
169         int *offset_ptr;
170 
171         /* move this ptr to vbase descriptor */
172         object = (char *)object + off->vbase_descr;
173         /* and fetch additional offset from vbase descriptor */
174         offset_ptr = (int *)(*(char **)object + off->vbase_offset);
175         object = (char *)object + *offset_ptr;
176     }
177 
178     object = (char *)object + off->this_offset;
179     return object;
180 }
181 
182 #endif /* __MSVCRT_CPPEXCEPT_H */
183