On Fri, Dec 7, 2012 at 1:59 PM, Steve Ellcey <sell...@mips.com> wrote: > This is my attempt to fix PR 54061, a bug where GCC aborts while trying to > put out debug information for a co-processor register. My understanding is > that gdb cannot access the coprocessor registers and so there is no valid > debug information that can be put out for this case. So my fix is to remove > the assert from dbx_reg_number and change the callers to check for a > INVALID_REGNUM value coming from dbx_reg_number. If they get this value > then they do not put out any debug information for the register. I have > tested this on gcc.c-torture/compile/mipscop-[1234].c and it fixes the abort. > > I haven't done a full regression test but will do that shortly, in the mean > time I wanted to see if this approach was considered acceptable and if not, > how I should fix it? > > Steve Ellcey > sell...@mips.com > > > 2012-12-07 Steve Ellcey <sell...@mips.com> > > PR target/54061 > * dwarfwout.c (dbx_reg_number): Remove assert. > (reg_loc_descriptor): Check for INVALID_REGNUM. > (mem_loc_descriptor): Ditto. > > diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c > index f0256ae..7d26e7e 100644 > --- a/gcc/dwarf2out.c > +++ b/gcc/dwarf2out.c > @@ -10438,7 +10438,6 @@ dbx_reg_number (const_rtx rtl) > #endif > > regno = DBX_REGISTER_NUMBER (regno); > - gcc_assert (regno != INVALID_REGNUM); > return regno; > }
I added it for http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52857 In this bug, we used the wrong register to generate DWARF info. Your patch removes the assert, which may make GCC silently generate bad DWARF info. > @@ -10473,6 +10472,9 @@ reg_loc_descriptor (rtx rtl, enum var_init_status > initialized) > if (REGNO (rtl) >= FIRST_PSEUDO_REGISTER) > return 0; > > + if (dbx_reg_number(rtl) == INVALID_REGNUM) > + return 0; > + > /* We only use "frame base" when we're sure we're talking about the > post-prologue local stack frame. We do this by *not* running > register elimination until this point, and recognizing the special > @@ -11931,6 +11933,8 @@ mem_loc_descriptor (rtx rtl, enum machine_mode mode, > break; > if (REGNO (rtl) > FIRST_PSEUDO_REGISTER) > break; > + if (dbx_reg_number (rtl) == INVALID_REGNUM) > + break; > type_die = base_type_for_mode (mode, > GET_MODE_CLASS (mode) == MODE_INT); > if (type_die == NULL) > @@ -12133,6 +12137,9 @@ mem_loc_descriptor (rtx rtl, enum machine_mode mode, > return NULL; > if (REG_P (ENTRY_VALUE_EXP (rtl))) > { > + if (dbx_reg_number (ENTRY_VALUE_EXP (rtl)) == INVALID_REGNUM) > + return NULL; > + > if (GET_MODE_CLASS (mode) != MODE_INT > || GET_MODE_SIZE (mode) > DWARF2_ADDR_SIZE) > op0 = mem_loc_descriptor (ENTRY_VALUE_EXP (rtl), mode, I think you need a way to tell a bad register from a good register which doesn't have DWARF register number. -- H.J.
