1 // -*- C++ -*- ARM specific Exception handling support routines.
2 // Copyright (C) 2004-2019 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