On Fri, Dec 7, 2012 at 2:17 PM, H.J. Lu <hjl.to...@gmail.com> wrote: > 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. >
Something like #define IGNORED_DWARF_REGNUM (INVALID_REGNUM - 1) -- H.J.
