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linux-unwind.h (frob_update_context <__powerpc64__>): Leave r2 REG_UNSAVED if stopped on the instruction that saves r2 in a plt call stub.

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* config/rs6000/linux-unwind.h (frob_update_context <__powerpc64__>):
	Leave r2 REG_UNSAVED if stopped on the instruction that saves r2
	in a plt call stub.  Do restore r2 if stopped on bctrl.

From-SVN: r176861
This commit is contained in:
Alan Modra 2011-07-28 17:14:24 +09:30 • committed by Alan Modra
parent d8fa1b739f
commit 2374a88acf
2 changed files with 28 additions and 4 deletions
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6
libgcc/ChangeLog
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@ -1,3 +1,9 @@
2011-07-28 Alan Modra <amodra@gmail.com>
* config/rs6000/linux-unwind.h (frob_update_context <__powerpc64__>):
Leave r2 REG_UNSAVED if stopped on the instruction that saves r2
in a plt call stub. Do restore r2 if stopped on bctrl.
2011-07-18 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
* config.host (i[3456x]86-*-netware*): Remove.

26
libgcc/config/rs6000/linux-unwind.h
View file

@ -346,10 +346,28 @@ frob_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs ATT
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. */
unsigned int *insn
= (unsigned int *) _Unwind_GetGR (context, R_LR);
if (insn && *insn == 0xE8410028)
_Unwind_SetGRPtr (context, 2, context->cfa + 40);
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 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. */
_Unwind_SetGRPtr (context, 2, context->cfa + 40);
}
else
{
unsigned int *insn
= (unsigned int *) _Unwind_GetGR (context, R_LR);
if (insn && *insn == 0xE8410028)
_Unwind_SetGRPtr (context, 2, context->cfa + 40);
}
}
#endif
}