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- /* DWARF2 EH unwinding support for PowerPC64 FreeBSD.
- Copyright (C) 2012-2022 Free Software Foundation, Inc.
- This file is part of GCC.
- GCC is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
- GCC is distributed in the hope that it will be useful, but WITHOUT
- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
- License for more details.
- Under Section 7 of GPL version 3, you are granted additional
- permissions described in the GCC Runtime Library Exception, version
- 3.1, as published by the Free Software Foundation.
- You should have received a copy of the GNU General Public License and
- a copy of the GCC Runtime Library Exception along with this program;
- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
- <http://www.gnu.org/licenses/>. */
- #define R_LR 65
- #define MD_FROB_UPDATE_CONTEXT frob_update_context
- static void
- frob_update_context (struct _Unwind_Context *context,
- _Unwind_FrameState *fs ATTRIBUTE_UNUSED)
- {
- const unsigned int *pc = (const unsigned int *) context->ra;
- #ifdef __powerpc64__
- if (fs->regs.reg[2].how == REG_UNSAVED)
- {
- /* If the current unwind info (FS) does not contain explicit info
- saving R2, then we have to do a minor amount of code reading to
- figure out if it was saved. The big problem here is that the
- code that does the save/restore is generated by the linker, so
- we have no good way to determine at compile time what to do. */
- if (pc[0] == 0xF8410028
- || ((pc[0] & 0xFFFF0000) == 0x3D820000
- && pc[1] == 0xF8410028))
- {
- /* We are in a plt call stub or r2 adjusting long branch stub,
- before r2 has been saved. Keep REG_UNSAVED. */
- }
- else
- {
- unsigned int *insn
- = (unsigned int *) _Unwind_GetGR (context, R_LR);
- if (insn && *insn == 0xE8410028)
- _Unwind_SetGRPtr (context, 2, context->cfa + 40);
- else if (pc[0] == 0x4E800421
- && pc[1] == 0xE8410028)
- {
- /* We are at the bctrl instruction in a call via function
- pointer. gcc always emits the load of the new R2 just
- before the bctrl so this is the first and only place
- we need to use the stored R2. */
- _Unwind_Word sp = _Unwind_GetGR (context, 1);
- _Unwind_SetGRPtr (context, 2, (void *)(sp + 40));
- }
- }
- }
- #endif
- }
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