Remove workaround for register stack overwrite bug in mmix.
* config/mmix/mmix.c (mmix_target_asm_function_prologue): Remove
support for TARGET_REG_STACK_FILL_BUG.
* config/mmix/mmix.h: Remove member has_call_without_parameters.
(TARGET_MASK_REG_STACK_FILL_BUG, TARGET_REG_STACK_FILL_BUG):
Delete.
(TARGET_DEFAULT): Remove TARGET_MASK_REG_STACK_FILL_BUG.
(TARGET_SWITCHES): Remove -mreg-stack-fill-bug-workaround and
-mno-reg-stack-fill-bug-workaround.
* config/mmix/mmix.md ("call", "call_value"): Don't set struct
machine member has_call_without_parameters.
* doc/invoke.texi (Option Summary) <MMIX Options>: Remove
-mreg-stack-fill-bug-workaround and
-mno-reg-stack-fill-bug-workaround.
(MMIX Options): Ditto.
From-SVN: r49035
This commit is contained in:
Hans-Peter Nilsson
Hans-Peter Nilsson
parent
7192cbf1e2
commit
07338cf892
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@ -1,3 +1,21 @@
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2002-01-21 Hans-Peter Nilsson <hp@bitrange.com>
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Remove workaround for register stack overwrite bug in mmix.
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* config/mmix/mmix.c (mmix_target_asm_function_prologue): Remove
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support for TARGET_REG_STACK_FILL_BUG.
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* config/mmix/mmix.h: Remove member has_call_without_parameters.
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(TARGET_MASK_REG_STACK_FILL_BUG, TARGET_REG_STACK_FILL_BUG):
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Delete.
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(TARGET_DEFAULT): Remove TARGET_MASK_REG_STACK_FILL_BUG.
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(TARGET_SWITCHES): Remove -mreg-stack-fill-bug-workaround and
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-mno-reg-stack-fill-bug-workaround.
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* config/mmix/mmix.md ("call", "call_value"): Don't set struct
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machine member has_call_without_parameters.
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* doc/invoke.texi (Option Summary) <MMIX Options>: Remove
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-mreg-stack-fill-bug-workaround and
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-mno-reg-stack-fill-bug-workaround.
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(MMIX Options): Ditto.
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2002-01-21 Kazu Hirata <kazu@hxi.com>
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* config/h8300/h8300.c (function_arg): Replace 0 with NULL_RTX
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@ -966,52 +966,6 @@ mmix_target_asm_function_prologue (stream, locals_size)
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break;
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mmix_highest_saved_stack_register = regno;
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/* FIXME: Remove this when a corrected mmix version is released.
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This kludge is a work-around for a presumed bug in the mmix simulator
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(reported to knuth-bug), all versions up and including "Version of 14
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October 2001". When the circular register stack fills up, the parts
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that would be overwritten need to be written to memory. If the
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"filling" instruction is a PUSHJ or PUSHGO, rL == 0 afterwards. That
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precise condition (rS == rO && rL == 0) is the same as for an empty
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register stack, which means no more data is written to memory for
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that round. A hack is to remove the "&& L!=0" from "@<Increase
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rL@>=" in mmix-sim.w: the register stack isn't empty under normal
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circumstances, unless SAVE or UNSAVE is used, interrupts are enabled
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or cases where rS == rO and rL is explicitly written to 0 as in
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"PUT rL,0".
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A workaround is to make sure PUSHJ or PUSHGO isn't filling up the
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register stac. This is accomplished if $16 or higher is written
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before the function call. This doesn't happen from a leaf functions
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of course. For the MMIXware ABI, this can't happen if all called
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functions have parameters, because parameters start at $16.
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Otherwise, and for the GNU ABI, if any register $16 and up is used,
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we can see if it's mentioned before any function-call without
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parameters. This isn't too important; the bug will probably be fixed
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soon and there's an option to not emit the work-around code. The
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call-with-parameters kludge wouldn't be there if it hadn't been for
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it being left-over from a previous mmix version.
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The actual code makes sure any register stack fill happens as early
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as in the function prologue with a "SET $16,$16" (essentially a nop
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except for the effects on the register stack). */
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if (TARGET_REG_STACK_FILL_BUG
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&& ((TARGET_ABI_GNU && !leaf_function_p ())
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|| (!TARGET_ABI_GNU
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&& cfun->machine->has_call_without_parameters)))
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{
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/* We don't have a specific macro or derivable expression for the
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first non-call-saved register. If we need it in other places
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than here (which is temporary code anyway), such a macro should
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be added. */
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int flush_regno
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= TARGET_ABI_GNU ? mmix_highest_saved_stack_register + 2 : 16;
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fprintf (stream, "\tSET %s,%s\n",
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reg_names[flush_regno], reg_names[flush_regno]);
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}
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}
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/* TARGET_ASM_FUNCTION_EPILOGUE. */
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@ -90,7 +90,6 @@ extern struct rtx_def *mmix_compare_op1;
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mmix.md too. */
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struct machine_function
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{
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int has_call_without_parameters;
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int has_landing_pad;
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};
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@ -157,7 +156,6 @@ extern int target_flags;
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#define TARGET_MASK_KNUTH_DIVISION 16
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#define TARGET_MASK_TOPLEVEL_SYMBOLS 32
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#define TARGET_MASK_BRANCH_PREDICT 64
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#define TARGET_MASK_REG_STACK_FILL_BUG 128
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/* FIXME: Get rid of this one. */
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#define TARGET_LIBFUNC (target_flags & TARGET_MASK_LIBFUNCS)
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@ -167,11 +165,9 @@ extern int target_flags;
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#define TARGET_KNUTH_DIVISION (target_flags & TARGET_MASK_KNUTH_DIVISION)
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#define TARGET_TOPLEVEL_SYMBOLS (target_flags & TARGET_MASK_TOPLEVEL_SYMBOLS)
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#define TARGET_BRANCH_PREDICT (target_flags & TARGET_MASK_BRANCH_PREDICT)
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#define TARGET_REG_STACK_FILL_BUG \
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(target_flags & TARGET_MASK_REG_STACK_FILL_BUG)
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#define TARGET_DEFAULT \
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(TARGET_MASK_BRANCH_PREDICT | TARGET_MASK_REG_STACK_FILL_BUG)
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(TARGET_MASK_BRANCH_PREDICT)
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/* FIXME: Provide a way to *load* the epsilon register. */
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#define TARGET_SWITCHES \
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@ -202,12 +198,6 @@ extern int target_flags;
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N_("Use P-mnemonics for branches statically predicted as taken")}, \
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{"no-branch-predict", -TARGET_MASK_BRANCH_PREDICT, \
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N_("Don't use P-mnemonics for branches")}, \
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{"reg-stack-fill-bug-workaround", TARGET_MASK_REG_STACK_FILL_BUG, \
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N_("Work around inconsistent behavior when a PUSHJ or PUSHGO\
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instruction fills the register stack")}, \
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{"no-reg-stack-fill-bug-workaround", -TARGET_MASK_REG_STACK_FILL_BUG,\
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N_("Don't work around inconsistent behavior when a PUSHJ or PUSHGO\
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instruction fills the register stack")}, \
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{"", TARGET_DEFAULT, ""}}
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/* Unfortunately, this must not reference anything in "mmix.c". */
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@ -996,11 +996,6 @@ DIVU %1,%1,%2\;GET %0,:rR\;NEGU %2,0,%0\;CSNN %0,$255,%2")
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if (operands[2] == NULL_RTX)
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operands[2] = const0_rtx;
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/* FIXME: Documentation bug: operands[3] (operands[2] for 'call') is the
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*next* argument register, not the number of arguments in registers. */
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cfun->machine->has_call_without_parameters
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|= REG_P (operands[2]) && REGNO (operands[2]) == MMIX_FIRST_ARG_REGNUM;
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operands[4] = gen_rtx_REG (DImode, MMIX_INCOMING_RETURN_ADDRESS_REGNUM);
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}")
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@ -1025,9 +1020,8 @@ DIVU %1,%1,%2\;GET %0,:rR\;NEGU %2,0,%0\;CSNN %0,$255,%2")
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operands[3] = const0_rtx;
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/* FIXME: Documentation bug: operands[3] (operands[2] for 'call') is the
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*next* argument register, not the number of arguments in registers. */
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cfun->machine->has_call_without_parameters
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|= REG_P (operands[3]) && REGNO (operands[3]) == MMIX_FIRST_ARG_REGNUM;
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*next* argument register, not the number of arguments in registers.
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(There used to be code here where that mattered.) */
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operands[5] = gen_rtx_REG (DImode, MMIX_INCOMING_RETURN_ADDRESS_REGNUM);
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}")
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@ -593,8 +593,7 @@ in the following sections.
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@gccoptlist{
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-mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol
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-mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols @gol
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-melf -mbranch-predict -mreg-stack-fill-bug-workaround @gol
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-mno-branch-predict -mno-reg-stack-fill-bug-workaround}
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-melf -mbranch-predict -mno-branch-predict}
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@emph{IA-64 Options}
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@gccoptlist{
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@ -9486,15 +9485,6 @@ Generate an executable in the ELF format, rather than the default
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@opindex mno-branch-predict
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Use (do not use) the probable-branch instructions, when static branch
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prediction indicates a probable branch.
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@item -mreg-stack-fill-bug-workaround
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@itemx -mno-reg-stack-fill-bug-workaround
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@opindex mreg-stack-fill-bug-workaround
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@opindex mno-reg-stack-fill-bug-workaround
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Work around (do not work around) an inconsistency in the circular
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register stack mechanism in the @command{mmix} simulator, which
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causes entries in the register stack to not be flushed to memory if
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the instruction causing the fill-up is @code{PUSHJ} or @code{PUSHGO}.
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@end table
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@node PDP-11 Options
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