| Message ID | VI1PR0801MB21270C1BC7FCECB5E3E2AB5B831E0@VI1PR0801MB2127.eurprd08.prod.outlook.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix PR84521 | expand |
On 5/28/19 11:37 AM, Wilco Dijkstra wrote: > This fixes and simplifies the setjmp and non-local goto implementation. > Currently the virtual frame pointer is saved when using __builtin_setjmp or > a non-local goto. Depending on whether a frame pointer is used, this may > either save SP or FP with an immediate offset. However the goto or longjmp > always updates the hard frame pointer. > > A receiver veneer in the original function then assigns the hard frame pointer > to the virtual frame pointer, which should, if it works correctly, again assign > SP or FP. However the special elimination code in eliminate_regs_in_insn > doesn't do this correctly unless the frame pointer is used, and even if it > worked by writing SP, the frame pointer would still be corrupted. > > A much simpler implementation is to always save and restore the hard frame > pointer. This avoids 2 redundant instructions which add/subtract the virtual > frame offset. A large amount of code can be removed as a result, including all > implementations of TARGET_BUILTIN_SETJMP_FRAME_VALUE (all of which already use > the hard frame pointer). The expansion of nonlocal_goto on PA can be simplied > to just restore the hard frame pointer. > > This fixes the most obvious issues, however there are still issues on targets > which define HARD_FRAME_POINTER_IS_FRAME_POINTER (arm, mips, xtensa). > Each function could have a different hard frame pointer, so a non-local goto > may restore the wrong frame pointer (TARGET_BUILTIN_SETJMP_FRAME_VALUE could > be useful for this). > > The i386 TARGET_BUILTIN_SETJMP_FRAME_VALUE was incorrect: if stack_realign_fp > is true, it would save the hard frame pointer value but restore the virtual > frame pointer which according to ix86_initial_elimination_offset can have a > non-zero offset from the hard frame pointer. > > The ia64 implementation of nonlocal_goto seems incorrect since the helper > function moves the the frame pointer value into the static chain register > (so this patch does nothing to make it better or worse). > > AArch64 bootstrap OK, new test passes on AArch64, x86-64 and Arm. > > ChangeLog: > 2018-12-13 Wilco Dijkstra <wdijkstr@arm.com> > > gcc/ > PR middle-end/84521 > * builtins.c (expand_builtin_setjmp_setup): Save hard_frame_pointer_rtx. > (expand_builtin_setjmp_receiver): Do not emit sfp = fp move since we restore fp. > * function.c (expand_function_start): Save hard_frame_pointer_rtx for non-local goto. > * lra-eliminations.c (eliminate_regs_in_insn): Remove sfp = fp elimination code. > (remove_reg_equal_offset_note): Remove unused function. > * reload1.c (eliminate_regs_in_insn): Remove sfp = hfp elimination code. > * config/arc/arc.c (TARGET_BUILTIN_SETJMP_FRAME_VALUE): Remove. > (arc_builtin_setjmp_frame_value): Remove function. > * config/avr/avr.c (TARGET_BUILTIN_SETJMP_FRAME_VALUE): Remove. > (avr_builtin_setjmp_frame_value): Remove function. > * config/i386/i386.c (TARGET_BUILTIN_SETJMP_FRAME_VALUE): Remove. > (ix86_builtin_setjmp_frame_value): Remove function. > * config/pa/pa.md (nonlocal_goto): Remove FP adjustment. > * config/sparc/sparc.c (TARGET_BUILTIN_SETJMP_FRAME_VALUE): Remove. > (sparc_builtin_setjmp_frame_value): Remove function. > * config/vax/vax.c (TARGET_BUILTIN_SETJMP_FRAME_VALUE): Remove. > (vax_builtin_setjmp_frame_value): Remove function. > > testsuite/ > PR middle-end/84521 > * gcc.c-torture/execute/pr84521.c: New test. > So I like the significant simplification here. My worry is whether or not this is, in effect, an ABI change. ie, would we be able to mix and match .o files from before/after this change which used the builtin setjmp/longjmp bits? You mention that arm, mips and xtensa are still broken. Are they worse after this patch? Presumably for arm/mips the problem is the frame pointer varies based on the thumb/mips and mips/mips16 state? Is it even valid to longjmp from one mode to the other? I think xtensa has two abis and the frame pointer is different across them. Presumably a longjmp from one abi to the other isn't valid. Or am I missing something? jeff
Hi Jeff, > So I like the significant simplification here. My worry is whether or > not this is, in effect, an ABI change. ie, would we be able to mix and > match .o files from before/after this change which used the builtin > setjmp/longjmp bits? No it's not an ABI change. It does affect the value stored in the setjmp record, but that is entirely local to the function containing setjmp. Note that the function containing the longjmp is not affected by this change. > You mention that arm, mips and xtensa are still broken. Are they worse > after this patch? Presumably for arm/mips the problem is the frame > pointer varies based on the thumb/mips and mips/mips16 state? Is it > even valid to longjmp from one mode to the other? Yes the only remaining issue after this is the fact that these targets can use different frame pointers in functions. The generic code doesn't consider this, but any function could be Arm or Thumb, mips or mips16. One solution would be to pass the frame pointer in an argument register (that would be an ABI change). > I think xtensa has two abis and the frame pointer is different across > them. Presumably a longjmp from one abi to the other isn't valid. If it isn't possible to call functions with the other frame pointer then it won't be affected. Wilco
On 6/17/19 6:58 PM, Wilco Dijkstra wrote: > Hi Jeff, > >> So I like the significant simplification here. My worry is whether or >> not this is, in effect, an ABI change. ie, would we be able to mix and >> match .o files from before/after this change which used the builtin >> setjmp/longjmp bits? > > No it's not an ABI change. It does affect the value stored in the setjmp > record, but that is entirely local to the function containing setjmp. > Note that the function containing the longjmp is not affected by this > change. OK. Thanks for the clarification. > >> You mention that arm, mips and xtensa are still broken. Are they worse >> after this patch? Presumably for arm/mips the problem is the frame >> pointer varies based on the thumb/mips and mips/mips16 state? Is it >> even valid to longjmp from one mode to the other? > > Yes the only remaining issue after this is the fact that these targets can use > different frame pointers in functions. The generic code doesn't consider this, > but any function could be Arm or Thumb, mips or mips16. One solution > would be to pass the frame pointer in an argument register (that would be > an ABI change). ACK. I think if we want to make this work (arm <-> thumb or mips <-> mips16) then we should take that up separately. > >> I think xtensa has two abis and the frame pointer is different across >> them. Presumably a longjmp from one abi to the other isn't valid. > > If it isn't possible to call functions with the other frame pointer then it > won't be affected. I'd be surprised given it's two distinct abis as opposed to a processor mode change like we see in the arm/mips cases. OK for the trunk. Thanks for your patience. jeff
Hello, On Mon, Jun 17, 2019 at 6:10 PM Jeff Law <law@redhat.com> wrote: > On 6/17/19 6:58 PM, Wilco Dijkstra wrote: > >> You mention that arm, mips and xtensa are still broken. Are they worse > >> after this patch? The testcase from the patch passes with the trunk xtensa-linux-gcc with windowed ABI. But with the changes in this patch a lot of tests that use longjmp are failing on xtensa-linux. > >> I think xtensa has two abis and the frame pointer is different across > >> them. Presumably a longjmp from one abi to the other isn't valid. call0 and windowed ABI xtensa code are not supposed to work together.
On Tue, May 28, 2019 at 10:37 AM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote: > > > diff --git a/gcc/testsuite/gcc.c-torture/execute/pr84521.c b/gcc/testsuite/gcc.c-torture/execute/pr84521.c > new file mode 100644 > index 0000000000000000000000000000000000000000..995a30223afd1401186c7eaf541f27606aed59b5 > --- /dev/null > +++ b/gcc/testsuite/gcc.c-torture/execute/pr84521.c > @@ -0,0 +1,54 @@ > +/* { dg-require-effective-target indirect_jumps } */ > +/* { dg-additional-options "-fomit-frame-pointer -fno-inline" } */ > + > +extern void abort (void); > + > +void > +broken_longjmp (void *p) > +{ > + __builtin_longjmp (p, 1); > +} > + > +volatile int x = 256; > +void *volatile p = (void*)&x; > +void *volatile p1; > + > +void > +test (void) > +{ > + void *buf[5]; > + void *volatile q = p; > + > + if (!__builtin_setjmp (buf)) > + broken_longjmp (buf); Is this test valid? Can jmp buffer be allowed on stack? > + /* Fails if stack pointer corrupted. */ > + if (p != q) > + abort (); > +} > + > +void > +test2 (void) > +{ > + void *volatile q = p; > + p1 = __builtin_alloca (x); > + test (); > + > + /* Fails if frame pointer corrupted. */ > + if (p != q) > + abort (); > +} > + > +int > +main (void) > +{ > + void *volatile q = p; > + test (); > + test2 (); > + /* Fails if stack pointer corrupted. */ > + if (p != q) > + abort (); > + > + return 0; > +} > +
Hi Max, > The testcase from the patch passes with the trunk xtensa-linux-gcc > with windowed ABI. But with the changes in this patch a lot of tests > that use longjmp are failing on xtensa-linux. Interesting. I looked at the _xtensa_nonlocal_goto implementation in libgcc/config/xtensa/lib2funcs.S, and it should work fine given it already checks for the frame pointer to be within the bounds of a frame. Whether we pass the virtual frame pointer or the hard frame pointer value shouldn't matter as long as both are >= SP and < prev_SP. Maybe there is an off by one issue in: .Lfirstframe: l32i a7, a6, 4 /* a7 = next */ bgeu a2, a7, .Lnextframe > call0 and windowed ABI xtensa code are not supposed to work together. OK so that's not an issue then. Wilco
On Jun 18 2019, "H.J. Lu" <hjl.tools@gmail.com> wrote: >> +void >> +test (void) >> +{ >> + void *buf[5]; >> + void *volatile q = p; >> + >> + if (!__builtin_setjmp (buf)) >> + broken_longjmp (buf); > > Is this test valid? Can jmp buffer be allowed on stack? Sure, the contents of the jmp buffer is only valid during the lifetime of the call frame anyway. Andreas.
Hi, > > Is this test valid? Can jmp buffer be allowed on stack? > > Sure, the contents of the jmp buffer is only valid during the lifetime > of the call frame anyway. Indeed. The issue with jmp buffer being on the stack causing incorrect restore when doing longjmp has just been fixed (PR64242). Wilco
On Tue, Jun 18, 2019 at 10:07 AM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote: > > The testcase from the patch passes with the trunk xtensa-linux-gcc > > with windowed ABI. But with the changes in this patch a lot of tests > > that use longjmp are failing on xtensa-linux. > > Interesting. I looked at the _xtensa_nonlocal_goto implementation in > libgcc/config/xtensa/lib2funcs.S, and it should work fine given it already > checks for the frame pointer to be within the bounds of a frame. It would work if a frame pointer was initialized in the function test, but it wasn't: test: entry sp, 64 l32r a2, .LC1 memw l32i.n a2, a2, 0 memw s32i.n a2, sp, 20 s32i.n a7, sp, 0 <---- l32r a2, .LC2 s32i.n a2, sp, 4 original version stored the sp there.
Hi Max, > It would work if a frame pointer was initialized in the function test, but > it wasn't: Right, because it unwinds, it needs a valid frame pointer since we no longer store the stack pointer. So xtensa_frame_pointer_required should do something like: if (cfun->machine->accesses_prev_frame || cfun->has_nonlocal_label) return true; Wilco
On Tue, Jun 18, 2019 at 4:53 PM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote: > > It would work if a frame pointer was initialized in the function test, but > > it wasn't: > > Right, because it unwinds, it needs a valid frame pointer since we no > longer store the stack pointer. So xtensa_frame_pointer_required > should do something like: > > if (cfun->machine->accesses_prev_frame || cfun->has_nonlocal_label) > return true; You're right, with this change things are back to normal.
Hi Max, > On Tue, Jun 18, 2019 at 4:53 PM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote: > > > It would work if a frame pointer was initialized in the function test, but > > > it wasn't: > > > > Right, because it unwinds, it needs a valid frame pointer since we no > > longer store the stack pointer. So xtensa_frame_pointer_required > > should do something like: > > > > if (cfun->machine->accesses_prev_frame || cfun->has_nonlocal_label) > > return true; > > You're right, with this change things are back to normal. Great, I've added this to the commit. Thanks for the proactive testing! Wilco
diff --git a/gcc/builtins.c b/gcc/builtins.c index 3463ffb153914a58e5baa3896a244842a28eef09..4ecfd49d03cb34600e7ac7afb0bf0511ff7ec1fa 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -981,7 +981,7 @@ expand_builtin_setjmp_setup (rtx buf_addr, rtx receiver_label) mem = gen_rtx_MEM (Pmode, buf_addr); set_mem_alias_set (mem, setjmp_alias_set); - emit_move_insn (mem, targetm.builtin_setjmp_frame_value ()); + emit_move_insn (mem, hard_frame_pointer_rtx); mem = gen_rtx_MEM (Pmode, plus_constant (Pmode, buf_addr, GET_MODE_SIZE (Pmode))), @@ -1023,31 +1023,6 @@ expand_builtin_setjmp_receiver (rtx receiver_label) if (chain && REG_P (chain)) emit_clobber (chain); - /* Now put in the code to restore the frame pointer, and argument - pointer, if needed. */ - if (! targetm.have_nonlocal_goto ()) - { - /* First adjust our frame pointer to its actual value. It was - previously set to the start of the virtual area corresponding to - the stacked variables when we branched here and now needs to be - adjusted to the actual hardware fp value. - - Assignments to virtual registers are converted by - instantiate_virtual_regs into the corresponding assignment - to the underlying register (fp in this case) that makes - the original assignment true. - So the following insn will actually be decrementing fp by - TARGET_STARTING_FRAME_OFFSET. */ - emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx); - - /* Restoring the frame pointer also modifies the hard frame pointer. - Mark it used (so that the previous assignment remains live once - the frame pointer is eliminated) and clobbered (to represent the - implicit update from the assignment). */ - emit_use (hard_frame_pointer_rtx); - emit_clobber (hard_frame_pointer_rtx); - } - if (!HARD_FRAME_POINTER_IS_ARG_POINTER && fixed_regs[ARG_POINTER_REGNUM]) { /* If the argument pointer can be eliminated in favor of the diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c index bce189958bc589c0003d2ea20dbbdf921ff715c6..d8282e633d77c6439426a5b164f01d4a59c5cdde 100644 --- a/gcc/config/arc/arc.c +++ b/gcc/config/arc/arc.c @@ -689,8 +689,6 @@ static rtx arc_legitimize_address_0 (rtx, rtx, machine_mode mode); #undef TARGET_MODES_TIEABLE_P #define TARGET_MODES_TIEABLE_P arc_modes_tieable_p -#undef TARGET_BUILTIN_SETJMP_FRAME_VALUE -#define TARGET_BUILTIN_SETJMP_FRAME_VALUE arc_builtin_setjmp_frame_value /* Try to keep the (mov:DF _, reg) as early as possible so that the d<add/sub/mul>h-lr insns appear together and can @@ -10979,28 +10977,6 @@ compact_memory_operand_p (rtx op, machine_mode mode, return false; } -/* Return the frame pointer value to be backed up in the setjmp buffer. */ - -static rtx -arc_builtin_setjmp_frame_value (void) -{ - /* We always want to preserve whatever value is currently in the frame - pointer register. For frames that are using the frame pointer the new - value of the frame pointer register will have already been computed - (as part of the prologue). For frames that are not using the frame - pointer it is important that we backup whatever value is in the frame - pointer register, as earlier (more outer) frames may have placed a - value into the frame pointer register. It might be tempting to try - and use `frame_pointer_rtx` here, however, this is not what we want. - For frames that are using the frame pointer this will give the - correct value. However, for frames that are not using the frame - pointer this will still give the value that _would_ have been the - frame pointer value for this frame (if the use of the frame pointer - had not been removed). We really do want the raw frame pointer - register value. */ - return gen_raw_REG (Pmode, HARD_FRAME_POINTER_REGNUM); -} - /* Return nonzero if a jli call should be generated for a call from the current function to DECL. */ diff --git a/gcc/config/avr/avr.c b/gcc/config/avr/avr.c index a9f72b314c2d397d2892a624c87e076682bcac09..f3896f79cd16e67503bd831aebfaff2efa6d02a3 100644 --- a/gcc/config/avr/avr.c +++ b/gcc/config/avr/avr.c @@ -1302,22 +1302,6 @@ avr_build_builtin_va_list (void) } -/* Implement `TARGET_BUILTIN_SETJMP_FRAME_VALUE'. */ -/* Actual start of frame is virtual_stack_vars_rtx this is offset from - frame pointer by +TARGET_STARTING_FRAME_OFFSET. - Using saved frame = virtual_stack_vars_rtx - TARGET_STARTING_FRAME_OFFSET - avoids creating add/sub of offset in nonlocal goto and setjmp. */ - -static rtx -avr_builtin_setjmp_frame_value (void) -{ - rtx xval = gen_reg_rtx (Pmode); - emit_insn (gen_subhi3 (xval, virtual_stack_vars_rtx, - gen_int_mode (avr_starting_frame_offset (), Pmode))); - return xval; -} - - /* Return contents of MEM at frame pointer + stack size + 1 (+2 if 3-byte PC). This is return address of function. */ diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 2eddea56b2e9e6470e75dd6dff6e2966078e8434..547e78e43102631e7883bfcbb777dd04c98aa2df 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -22764,9 +22764,6 @@ ix86_run_selftests (void) #undef TARGET_MACHINE_DEPENDENT_REORG #define TARGET_MACHINE_DEPENDENT_REORG ix86_reorg -#undef TARGET_BUILTIN_SETJMP_FRAME_VALUE -#define TARGET_BUILTIN_SETJMP_FRAME_VALUE ix86_builtin_setjmp_frame_value - #undef TARGET_BUILD_BUILTIN_VA_LIST #define TARGET_BUILD_BUILTIN_VA_LIST ix86_build_builtin_va_list diff --git a/gcc/config/pa/pa.md b/gcc/config/pa/pa.md index 8308b37461df89200f35f6ec7dbee4798375b9ea..29dd24010536164e12559e7bf09479c02739d21d 100644 --- a/gcc/config/pa/pa.md +++ b/gcc/config/pa/pa.md @@ -6909,13 +6909,7 @@ (define_expand "nonlocal_goto" emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode))); emit_clobber (gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx)); - /* Restore the frame pointer. The virtual_stack_vars_rtx is saved - instead of the hard_frame_pointer_rtx in the save area. As a - result, an extra instruction is needed to adjust for the offset - of the virtual stack variables and the hard frame pointer. */ - if (GET_CODE (fp) != REG) - fp = force_reg (Pmode, fp); - emit_move_insn (hard_frame_pointer_rtx, plus_constant (Pmode, fp, -8)); + emit_move_insn (hard_frame_pointer_rtx, fp); emit_stack_restore (SAVE_NONLOCAL, stack); diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c index 6d52f83d91c2ac44337bb0c6a9ebc57957ed7578..0227a53861fb4dc820e183db7e7687317d4e711d 100644 --- a/gcc/config/sparc/sparc.c +++ b/gcc/config/sparc/sparc.c @@ -679,7 +679,6 @@ static void sparc_output_dwarf_dtprel (FILE *, int, rtx) ATTRIBUTE_UNUSED; static void sparc_file_end (void); static bool sparc_frame_pointer_required (void); static bool sparc_can_eliminate (const int, const int); -static rtx sparc_builtin_setjmp_frame_value (void); static void sparc_conditional_register_usage (void); static bool sparc_use_pseudo_pic_reg (void); static void sparc_init_pic_reg (void); @@ -878,9 +877,6 @@ char sparc_hard_reg_printed[8]; #undef TARGET_FRAME_POINTER_REQUIRED #define TARGET_FRAME_POINTER_REQUIRED sparc_frame_pointer_required -#undef TARGET_BUILTIN_SETJMP_FRAME_VALUE -#define TARGET_BUILTIN_SETJMP_FRAME_VALUE sparc_builtin_setjmp_frame_value - #undef TARGET_CAN_ELIMINATE #define TARGET_CAN_ELIMINATE sparc_can_eliminate @@ -13003,14 +12999,6 @@ sparc_can_eliminate (const int from ATTRIBUTE_UNUSED, const int to) return to == HARD_FRAME_POINTER_REGNUM || !sparc_frame_pointer_required (); } -/* Return the hard frame pointer directly to bypass the stack bias. */ - -static rtx -sparc_builtin_setjmp_frame_value (void) -{ - return hard_frame_pointer_rtx; -} - /* If !TARGET_FPU, then make the fp registers and fp cc regs fixed so that they won't be allocated. */ diff --git a/gcc/config/vax/vax.c b/gcc/config/vax/vax.c index 547a7e068e49655993670e9a465fbc23f447b959..9559ffb9bb44185adc9b9a124f8cffdb69ba5959 100644 --- a/gcc/config/vax/vax.c +++ b/gcc/config/vax/vax.c @@ -59,7 +59,6 @@ static rtx vax_function_arg (cumulative_args_t, machine_mode, static void vax_function_arg_advance (cumulative_args_t, machine_mode, const_tree, bool); static rtx vax_struct_value_rtx (tree, int); -static rtx vax_builtin_setjmp_frame_value (void); static void vax_asm_trampoline_template (FILE *); static void vax_trampoline_init (rtx, tree, rtx); static poly_int64 vax_return_pops_args (tree, tree, poly_int64); @@ -99,9 +98,6 @@ static HOST_WIDE_INT vax_starting_frame_offset (void); #undef TARGET_STRUCT_VALUE_RTX #define TARGET_STRUCT_VALUE_RTX vax_struct_value_rtx -#undef TARGET_BUILTIN_SETJMP_FRAME_VALUE -#define TARGET_BUILTIN_SETJMP_FRAME_VALUE vax_builtin_setjmp_frame_value - #undef TARGET_LRA_P #define TARGET_LRA_P hook_bool_void_false @@ -1067,12 +1063,6 @@ vax_struct_value_rtx (tree fntype ATTRIBUTE_UNUSED, return gen_rtx_REG (Pmode, VAX_STRUCT_VALUE_REGNUM); } -static rtx -vax_builtin_setjmp_frame_value (void) -{ - return hard_frame_pointer_rtx; -} - /* Worker function for NOTICE_UPDATE_CC. */ void diff --git a/gcc/function.c b/gcc/function.c index e30ee259becc1cffb312fa186339ffd86a60de1c..9a3e9795a9926f37eb9f6ddeb79a6610a42b3eb8 100644 --- a/gcc/function.c +++ b/gcc/function.c @@ -5142,7 +5142,7 @@ expand_function_start (tree subr) r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE); gcc_assert (GET_MODE (r_save) == Pmode); - emit_move_insn (r_save, targetm.builtin_setjmp_frame_value ()); + emit_move_insn (r_save, hard_frame_pointer_rtx); update_nonlocal_goto_save_area (); } diff --git a/gcc/lra-eliminations.c b/gcc/lra-eliminations.c index ee9fd51f129d2cef1a2766d6bdf0345f906cdf0c..fa0ebcd8ed9b7bdff460957ecba5b50250c796b8 100644 --- a/gcc/lra-eliminations.c +++ b/gcc/lra-eliminations.c @@ -876,32 +876,6 @@ mark_not_eliminable (rtx x, machine_mode mem_mode) -#ifdef HARD_FRAME_POINTER_REGNUM - -/* Search INSN's reg notes to see whether the destination is equal to - WHAT + C for some constant C. Return true if so, storing C in - *OFFSET_OUT and removing the reg note. */ -static bool -remove_reg_equal_offset_note (rtx_insn *insn, rtx what, poly_int64 *offset_out) -{ - rtx link, *link_loc; - - for (link_loc = ®_NOTES (insn); - (link = *link_loc) != NULL_RTX; - link_loc = &XEXP (link, 1)) - if (REG_NOTE_KIND (link) == REG_EQUAL - && GET_CODE (XEXP (link, 0)) == PLUS - && XEXP (XEXP (link, 0), 0) == what - && poly_int_rtx_p (XEXP (XEXP (link, 0), 1), offset_out)) - { - *link_loc = XEXP (link, 1); - return true; - } - return false; -} - -#endif - /* Scan INSN and eliminate all eliminable hard registers in it. If REPLACE_P is true, do the replacement destructively. Also @@ -939,72 +913,6 @@ eliminate_regs_in_insn (rtx_insn *insn, bool replace_p, bool first_p, return; } - /* Check for setting an eliminable register. */ - if (old_set != 0 && REG_P (SET_DEST (old_set)) - && (ep = get_elimination (SET_DEST (old_set))) != NULL) - { - for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) - if (ep->from_rtx == SET_DEST (old_set) && ep->can_eliminate) - { - bool delete_p = replace_p; - -#ifdef HARD_FRAME_POINTER_REGNUM - if (ep->from == FRAME_POINTER_REGNUM - && ep->to == HARD_FRAME_POINTER_REGNUM) - /* If this is setting the frame pointer register to the - hardware frame pointer register and this is an - elimination that will be done (tested above), this - insn is really adjusting the frame pointer downward - to compensate for the adjustment done before a - nonlocal goto. */ - { - rtx src = SET_SRC (old_set); - poly_int64 offset = 0; - - /* We should never process such insn with non-zero - UPDATE_SP_OFFSET. */ - lra_assert (known_eq (update_sp_offset, 0)); - - if (remove_reg_equal_offset_note (insn, ep->to_rtx, &offset) - || strip_offset (src, &offset) == ep->to_rtx) - { - if (replace_p) - { - SET_DEST (old_set) = ep->to_rtx; - lra_update_insn_recog_data (insn); - return; - } - offset -= (ep->offset - ep->previous_offset); - src = plus_constant (Pmode, ep->to_rtx, offset); - - /* First see if this insn remains valid when we - make the change. If not, keep the INSN_CODE - the same and let the constraint pass fit it - up. */ - validate_change (insn, &SET_SRC (old_set), src, 1); - validate_change (insn, &SET_DEST (old_set), - ep->from_rtx, 1); - if (! apply_change_group ()) - { - SET_SRC (old_set) = src; - SET_DEST (old_set) = ep->from_rtx; - } - lra_update_insn_recog_data (insn); - /* Add offset note for future updates. */ - add_reg_note (insn, REG_EQUAL, copy_rtx (src)); - return; - } - } -#endif - - /* This insn isn't serving a useful purpose. We delete it - when REPLACE is set. */ - if (delete_p) - lra_delete_dead_insn (insn); - return; - } - } - /* We allow one special case which happens to work on all machines we currently support: a single set with the source or a REG_EQUAL note being a PLUS of an eliminable register and a constant. */ diff --git a/gcc/reload1.c b/gcc/reload1.c index 5039ceed5816dc5567274ff64e849c2c4f998bb4..3ad6f1d9c1f7a72c4c39ddbaa3e3caf3e903557e 100644 --- a/gcc/reload1.c +++ b/gcc/reload1.c @@ -3234,96 +3234,6 @@ eliminate_regs_in_insn (rtx_insn *insn, int replace) return 0; } - if (old_set != 0 && REG_P (SET_DEST (old_set)) - && REGNO (SET_DEST (old_set)) < FIRST_PSEUDO_REGISTER) - { - /* Check for setting an eliminable register. */ - for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) - if (ep->from_rtx == SET_DEST (old_set) && ep->can_eliminate) - { - /* If this is setting the frame pointer register to the - hardware frame pointer register and this is an elimination - that will be done (tested above), this insn is really - adjusting the frame pointer downward to compensate for - the adjustment done before a nonlocal goto. */ - if (!HARD_FRAME_POINTER_IS_FRAME_POINTER - && ep->from == FRAME_POINTER_REGNUM - && ep->to == HARD_FRAME_POINTER_REGNUM) - { - rtx base = SET_SRC (old_set); - rtx_insn *base_insn = insn; - HOST_WIDE_INT offset = 0; - - while (base != ep->to_rtx) - { - rtx_insn *prev_insn; - rtx prev_set; - - if (GET_CODE (base) == PLUS - && CONST_INT_P (XEXP (base, 1))) - { - offset += INTVAL (XEXP (base, 1)); - base = XEXP (base, 0); - } - else if ((prev_insn = prev_nonnote_insn (base_insn)) != 0 - && (prev_set = single_set (prev_insn)) != 0 - && rtx_equal_p (SET_DEST (prev_set), base)) - { - base = SET_SRC (prev_set); - base_insn = prev_insn; - } - else - break; - } - - if (base == ep->to_rtx) - { - rtx src = plus_constant (Pmode, ep->to_rtx, - offset - ep->offset); - - new_body = old_body; - if (! replace) - { - new_body = copy_insn (old_body); - if (REG_NOTES (insn)) - REG_NOTES (insn) = copy_insn_1 (REG_NOTES (insn)); - } - PATTERN (insn) = new_body; - old_set = single_set (insn); - - /* First see if this insn remains valid when we - make the change. If not, keep the INSN_CODE - the same and let reload fit it up. */ - validate_change (insn, &SET_SRC (old_set), src, 1); - validate_change (insn, &SET_DEST (old_set), - ep->to_rtx, 1); - if (! apply_change_group ()) - { - SET_SRC (old_set) = src; - SET_DEST (old_set) = ep->to_rtx; - } - - val = 1; - goto done; - } - } - - /* In this case this insn isn't serving a useful purpose. We - will delete it in reload_as_needed once we know that this - elimination is, in fact, being done. - - If REPLACE isn't set, we can't delete this insn, but needn't - process it since it won't be used unless something changes. */ - if (replace) - { - delete_dead_insn (insn); - return 1; - } - val = 1; - goto done; - } - } - /* We allow one special case which happens to work on all machines we currently support: a single set with the source or a REG_EQUAL note being a PLUS of an eliminable register and a constant. */ diff --git a/gcc/testsuite/gcc.c-torture/execute/pr84521.c b/gcc/testsuite/gcc.c-torture/execute/pr84521.c new file mode 100644 index 0000000000000000000000000000000000000000..995a30223afd1401186c7eaf541f27606aed59b5 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr84521.c @@ -0,0 +1,54 @@ +/* { dg-require-effective-target indirect_jumps } */ +/* { dg-additional-options "-fomit-frame-pointer -fno-inline" } */ + +extern void abort (void); + +void +broken_longjmp (void *p) +{ + __builtin_longjmp (p, 1); +} + +volatile int x = 256; +void *volatile p = (void*)&x; +void *volatile p1; + +void +test (void) +{ + void *buf[5]; + void *volatile q = p; + + if (!__builtin_setjmp (buf)) + broken_longjmp (buf); + + /* Fails if stack pointer corrupted. */ + if (p != q) + abort (); +} + +void +test2 (void) +{ + void *volatile q = p; + p1 = __builtin_alloca (x); + test (); + + /* Fails if frame pointer corrupted. */ + if (p != q) + abort (); +} + +int +main (void) +{ + void *volatile q = p; + test (); + test2 (); + /* Fails if stack pointer corrupted. */ + if (p != q) + abort (); + + return 0; +} +