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bdd1ee48 | 1 | /* DWARF2 EH unwinding support for PowerPC64 FreeBSD. |
fbd26352 | 2 | Copyright (C) 2012-2019 Free Software Foundation, Inc. |
bdd1ee48 | 3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU General Public License as published | |
8 | by the Free Software Foundation; either version 3, or (at your | |
9 | option) any later version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT | |
12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
13 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
14 | 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 | #define R_LR 65 | |
26 | ||
27 | #define MD_FROB_UPDATE_CONTEXT frob_update_context | |
28 | ||
29 | static void | |
30 | frob_update_context (struct _Unwind_Context *context, | |
31 | _Unwind_FrameState *fs ATTRIBUTE_UNUSED) | |
32 | { | |
33 | const unsigned int *pc = (const unsigned int *) context->ra; | |
34 | ||
35 | #ifdef __powerpc64__ | |
36 | if (fs->regs.reg[2].how == REG_UNSAVED) | |
37 | { | |
38 | /* If the current unwind info (FS) does not contain explicit info | |
39 | saving R2, then we have to do a minor amount of code reading to | |
40 | figure out if it was saved. The big problem here is that the | |
41 | code that does the save/restore is generated by the linker, so | |
42 | we have no good way to determine at compile time what to do. */ | |
43 | if (pc[0] == 0xF8410028 | |
44 | || ((pc[0] & 0xFFFF0000) == 0x3D820000 | |
45 | && pc[1] == 0xF8410028)) | |
46 | { | |
47 | /* We are in a plt call stub or r2 adjusting long branch stub, | |
48 | before r2 has been saved. Keep REG_UNSAVED. */ | |
49 | } | |
50 | else | |
51 | { | |
52 | unsigned int *insn | |
53 | = (unsigned int *) _Unwind_GetGR (context, R_LR); | |
54 | if (insn && *insn == 0xE8410028) | |
55 | _Unwind_SetGRPtr (context, 2, context->cfa + 40); | |
56 | else if (pc[0] == 0x4E800421 | |
57 | && pc[1] == 0xE8410028) | |
58 | { | |
59 | /* We are at the bctrl instruction in a call via function | |
60 | pointer. gcc always emits the load of the new R2 just | |
61 | before the bctrl so this is the first and only place | |
62 | we need to use the stored R2. */ | |
63 | _Unwind_Word sp = _Unwind_GetGR (context, 1); | |
64 | _Unwind_SetGRPtr (context, 2, (void *)(sp + 40)); | |
65 | } | |
66 | } | |
67 | } | |
68 | #endif | |
69 | } |