From 27aae18ce872409b70afef8503941c7e75c8d93d Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Sun, 5 Jan 2014 20:37:30 +0100 Subject: [PATCH] libdwfl: Only skip reset of return register for non-CIE-return regno (ppc64). For PPC64 we skip resetting the return register if it is already set. This is because on PPC64 there are two DWARF registers numbers that can represent the same register. Setting the return address again confuses the unwinder. But we do want to reset it if the register number (non-translated by the ppc64 ebl) is equal to the actual register number as set in the CIE as return address. This happens on older toolchains in .debug_frame where the return address is set to 108, but the ebl abi_cfi also sets register number 65. Signed-off-by: Mark Wielaard --- libdwfl/ChangeLog | 5 +++++ libdwfl/frame_unwind.c | 5 +++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index 766fb18ac..55980a572 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,3 +1,8 @@ +2014-01-05 Mark Wielaard + + * frame_unwind.c (handle_cfi): Only skip resetting return register + if the regno is not the actual CIE return address register. + 2014-01-02 Mark Wielaard * linux-pid-attach.c (dwfl_linux_proc_attach): Use strtol, not atoi. diff --git a/libdwfl/frame_unwind.c b/libdwfl/frame_unwind.c index 3ce45479b..dc99e40b6 100644 --- a/libdwfl/frame_unwind.c +++ b/libdwfl/frame_unwind.c @@ -585,8 +585,9 @@ handle_cfi (Dwfl_Frame *state, Dwarf_Addr pc, Dwarf_CFI *cfi, Dwarf_Addr bias) /* This is another strange PPC[64] case. There are two registers numbers that can represent the same DWARF return register number. We only want one to actually set the return - register value. */ - if (ra_set) + register value. But we always want to override the value if + the register is the actual CIE return address register. */ + if (ra_set && regno != frame->fde->cie->return_address_register) { unsigned r = regno; if (ebl_dwarf_to_regno (ebl, &r) && r == ra) -- 2.47.2