70 lines
2.5 KiB
C
70 lines
2.5 KiB
C
/* DWARF2 EH unwinding support for PowerPC64 FreeBSD.
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Copyright (C) 2012-2018 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published
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by the Free Software Foundation; either version 3, or (at your
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option) any later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#define R_LR 65
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#define MD_FROB_UPDATE_CONTEXT frob_update_context
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static void
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frob_update_context (struct _Unwind_Context *context,
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_Unwind_FrameState *fs ATTRIBUTE_UNUSED)
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{
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const unsigned int *pc = (const unsigned int *) context->ra;
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#ifdef __powerpc64__
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if (fs->regs.reg[2].how == REG_UNSAVED)
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{
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/* If the current unwind info (FS) does not contain explicit info
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saving R2, then we have to do a minor amount of code reading to
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figure out if it was saved. The big problem here is that the
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code that does the save/restore is generated by the linker, so
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we have no good way to determine at compile time what to do. */
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if (pc[0] == 0xF8410028
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|| ((pc[0] & 0xFFFF0000) == 0x3D820000
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&& pc[1] == 0xF8410028))
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{
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/* We are in a plt call stub or r2 adjusting long branch stub,
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before r2 has been saved. Keep REG_UNSAVED. */
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}
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else
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{
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unsigned int *insn
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= (unsigned int *) _Unwind_GetGR (context, R_LR);
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if (insn && *insn == 0xE8410028)
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_Unwind_SetGRPtr (context, 2, context->cfa + 40);
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else if (pc[0] == 0x4E800421
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&& pc[1] == 0xE8410028)
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{
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/* We are at the bctrl instruction in a call via function
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pointer. gcc always emits the load of the new R2 just
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before the bctrl so this is the first and only place
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we need to use the stored R2. */
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_Unwind_Word sp = _Unwind_GetGR (context, 1);
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_Unwind_SetGRPtr (context, 2, (void *)(sp + 40));
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}
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}
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}
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#endif
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}
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