1 // -*- C++ -*- ARM specific Exception handling support routines.
2 // Copyright (C) 2004-2022 Free Software Foundation, Inc.
3 //
4 // This file is part of GCC.
5 //
6 // GCC is free software; you can redistribute it and/or modify
7 // it under the terms of the GNU General Public License as published by
8 // the Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 //
11 // GCC 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
14 // GNU General Public License for more details.
15 //
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 //
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 #include <cxxabi.h>
26 #include "unwind-cxx.h"
27
28 #ifdef __ARM_EABI_UNWINDER__
29
30 using namespace __cxxabiv1;
31
32
33 // Given the thrown type THROW_TYPE, exception object UE_HEADER and a
34 // type CATCH_TYPE to compare against, return whether or not there is
35 // a match and if so, update *THROWN_PTR_P to point to either the
36 // type-matched object, or in the case of a pointer type, the object
37 // pointed to by the pointer.
38
39 extern "C" __cxa_type_match_result
__cxa_type_match(_Unwind_Exception * ue_header,const std::type_info * catch_type,bool is_reference,void ** thrown_ptr_p)40 __cxa_type_match(_Unwind_Exception* ue_header,
41 const std::type_info* catch_type,
42 bool is_reference __attribute__((__unused__)),
43 void** thrown_ptr_p)
44 {
45 bool forced_unwind
46 = __is_gxx_forced_unwind_class(ue_header->exception_class);
47 bool foreign_exception
48 = !forced_unwind && !__is_gxx_exception_class(ue_header->exception_class);
49 bool dependent_exception
50 = __is_dependent_exception(ue_header->exception_class);
51 __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
52 __cxa_dependent_exception *dx = __get_dependent_exception_from_ue(ue_header);
53 const std::type_info* throw_type;
54 void *thrown_ptr = 0;
55
56 if (forced_unwind)
57 throw_type = &typeid(abi::__forced_unwind);
58 else if (foreign_exception)
59 throw_type = &typeid(abi::__foreign_exception);
60 else
61 {
62 if (dependent_exception)
63 xh = __get_exception_header_from_obj (dx->primaryException);
64 throw_type = xh->exceptionType;
65 // We used to require the caller set the target of thrown_ptr_p,
66 // but that's incorrect -- the EHABI makes no such requirement
67 // -- and not all callers will set it. Fortunately callers that
68 // do initialize will always pass us the value we calculate
69 // here, so there's no backwards compatibility problem.
70 thrown_ptr = __get_object_from_ue (ue_header);
71 }
72
73 __cxa_type_match_result result = ctm_succeeded;
74
75 // Pointer types need to adjust the actual pointer, not
76 // the pointer to pointer that is the exception object.
77 // This also has the effect of passing pointer types
78 // "by value" through the __cxa_begin_catch return value.
79 if (throw_type->__is_pointer_p())
80 {
81 thrown_ptr = *(void**) thrown_ptr;
82 // We need to indicate the indirection to our caller.
83 result = ctm_succeeded_with_ptr_to_base;
84 }
85
86 if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
87 {
88 *thrown_ptr_p = thrown_ptr;
89 return result;
90 }
91
92 return ctm_failed;
93 }
94
95 // ABI defined routine called at the start of a cleanup handler.
96 extern "C" bool
__cxa_begin_cleanup(_Unwind_Exception * ue_header)97 __cxa_begin_cleanup(_Unwind_Exception* ue_header)
98 {
99 __cxa_eh_globals *globals = __cxa_get_globals();
100 __cxa_exception *header = __get_exception_header_from_ue(ue_header);
101 bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);
102
103
104 if (native)
105 {
106 header->propagationCount++;
107 // Add it to the chain if this is the first time we've seen this
108 // exception.
109 if (header->propagationCount == 1)
110 {
111 header->nextPropagatingException = globals->propagatingExceptions;
112 globals->propagatingExceptions = header;
113 }
114 }
115 else
116 {
117 // Remember the exception object, so end_cleanup can return it.
118 // These cannot be stacked, so we must abort if we already have
119 // a propagating exception.
120 if (globals->propagatingExceptions)
121 std::terminate ();
122 globals->propagatingExceptions = header;
123 }
124
125 return true;
126 }
127
128 // Do the work for __cxa_end_cleanup. Returns the currently propagating
129 // exception object.
130 extern "C" _Unwind_Exception *
__gnu_end_cleanup(void)131 __gnu_end_cleanup(void)
132 {
133 __cxa_exception *header;
134 __cxa_eh_globals *globals = __cxa_get_globals();
135
136 header = globals->propagatingExceptions;
137
138 // Check something hasn't gone horribly wrong.
139 if (!header)
140 std::terminate();
141
142 if (__is_gxx_exception_class(header->unwindHeader.exception_class))
143 {
144 header->propagationCount--;
145 if (header->propagationCount == 0)
146 {
147 // Remove exception from chain.
148 globals->propagatingExceptions = header->nextPropagatingException;
149 header->nextPropagatingException = NULL;
150 }
151 }
152 else
153 globals->propagatingExceptions = NULL;
154
155 return &header->unwindHeader;
156 }
157
158 #ifdef __TMS320C6X__
159 // Assembly wrapper to call __gnu_end_cleanup without clobbering
160 // function arguments to _Unwind_Resume.
161 asm (".global __cxa_end_cleanup\n"
162 " .type __cxa_end_cleanup, \"function\"\n"
163 "__cxa_end_cleanup:\n"
164 " stw .d2t2 B9, *B15--[10]\n"
165 " stw .d2t2 B8, *+B15[9]\n"
166 " stw .d2t2 B7, *+B15[8]\n"
167 " stw .d2t2 B6, *+B15[7]\n"
168 " stw .d2t2 B5, *+B15[6]\n"
169 " stw .d2t2 B4, *+B15[5]\n"
170 " stw .d2t1 A9, *+B15[4]\n"
171 " stw .d2t1 A8, *+B15[3]\n"
172 " stw .d2t1 A7, *+B15[2]\n"
173 " stw .d2t1 A6, *+B15[1]\n"
174 #ifdef _TMS320C6400_PLUS
175 " callp .s2 (__gnu_end_cleanup), B3\n"
176 #elif defined(_TMS320C6400)
177 " call .s2 (__gnu_end_cleanup)\n"
178 " addkpc .s2 1f, B3, 0\n"
179 " nop 4\n"
180 "1:\n"
181 #else
182 " call .s2 (__gnu_end_cleanup)\n"
183 " mvkl .s2 1f, B3\n"
184 " mvkh .s2 1f, B3\n"
185 " nop 3\n"
186 "1:\n"
187 #endif
188 " ldw .d2t1 *+B15[1], A6\n"
189 " ldw .d2t1 *+B15[2], A7\n"
190 " ldw .d2t1 *+B15[3], A8\n"
191 " ldw .d2t1 *+B15[4], A9\n"
192 " ldw .d2t2 *+B15[5], B4\n"
193 " ldw .d2t2 *+B15[6], B5\n"
194 " ldw .d2t2 *+B15[7], B6\n"
195 " ldw .d2t2 *+B15[8], B7\n"
196 " ldw .d2t2 *+B15[9], B8\n"
197 " ldw .d2t2 *++B15[10], B9\n"
198 " b .s2 _Unwind_Resume\n"
199 " nop 5\n");
200 #else
201 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
202 // Also push r4 to preserve stack alignment.
203 #ifdef __thumb__
204 asm (" .pushsection .text.__cxa_end_cleanup\n"
205 " .global __cxa_end_cleanup\n"
206 " .type __cxa_end_cleanup, \"function\"\n"
207 " .thumb_func\n"
208 "__cxa_end_cleanup:\n"
209 " push\t{r1, r2, r3, r4}\n"
210 " bl\t__gnu_end_cleanup\n"
211 " pop\t{r1, r2, r3, r4}\n"
212 " bl\t_Unwind_Resume @ Never returns\n"
213 " .popsection\n");
214 #else
215 asm (" .pushsection .text.__cxa_end_cleanup\n"
216 " .global __cxa_end_cleanup\n"
217 " .type __cxa_end_cleanup, \"function\"\n"
218 "__cxa_end_cleanup:\n"
219 " stmfd\tsp!, {r1, r2, r3, r4}\n"
220 " bl\t__gnu_end_cleanup\n"
221 " ldmfd\tsp!, {r1, r2, r3, r4}\n"
222 " bl\t_Unwind_Resume @ Never returns\n"
223 " .popsection\n");
224 #endif
225 #endif
226
227 #endif
228