i386: Add save_stack_nonlocal and restore_stack_nonlocal

Define STACK_SAVEAREA_MODE to hold both shadow stack and stack pointers.
Replace builtin_setjmp_setup and builtin_longjmp with save_stack_nonlocal
and restore_stack_nonlocal to support both builtin setjmp/longjmp as well
as non-local goto in nested functions.

OK for trunk?

H.J.
----
gcc/

	PR target/85397
	* config/i386/i386.h (STACK_SAVEAREA_MODE): New.
	* config/i386/i386.md (builtin_setjmp_setup): Removed.
	(builtin_longjmp): Likewise.
	(save_stack_nonlocal): New pattern.
	(restore_stack_nonlocal): Likewise.

gcc/testsuite/

	PR target/85397
	* gcc.dg/torture/pr85397-1.c: New test.
	* gcc.target/i386/cet-sjlj-6a.c: Adjusted.
	* gcc.target/i386/cet-sjlj-6b.c: Likewise.
---
 gcc/config/i386/i386.h                      |  11 +++
 gcc/config/i386/i386.md                     | 107 +++++++++++++---------------
 gcc/testsuite/gcc.dg/torture/pr85397-1.c    |  29 ++++++++
 gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c |   4 +-
 gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c |   4 +-
 5 files changed, 92 insertions(+), 63 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr85397-1.c

> -----Original Message-----
> From: Lu, Hongjiu
> Sent: Sunday, April 15, 2018 12:58 PM
> To: gcc-patches@gcc.gnu.org
> Cc: Uros Bizjak <ubizjak@gmail.com>; Tsimbalist, Igor V
> <igor.v.tsimbalist@intel.com>
> Subject: [PATCH] i386: Add save_stack_nonlocal and restore_stack_nonlocal
> 
> Define STACK_SAVEAREA_MODE to hold both shadow stack and stack
> pointers.
> Replace builtin_setjmp_setup and builtin_longjmp with save_stack_nonlocal
> and restore_stack_nonlocal to support both builtin setjmp/longjmp as well
> as non-local goto in nested functions.
> 
> OK for trunk?

OK.

Igor

> H.J.
> ----
> gcc/
> 
> 	PR target/85397
> 	* config/i386/i386.h (STACK_SAVEAREA_MODE): New.
> 	* config/i386/i386.md (builtin_setjmp_setup): Removed.
> 	(builtin_longjmp): Likewise.
> 	(save_stack_nonlocal): New pattern.
> 	(restore_stack_nonlocal): Likewise.
> 
> gcc/testsuite/
> 
> 	PR target/85397
> 	* gcc.dg/torture/pr85397-1.c: New test.
> 	* gcc.target/i386/cet-sjlj-6a.c: Adjusted.
> 	* gcc.target/i386/cet-sjlj-6b.c: Likewise.
> ---
>  gcc/config/i386/i386.h                      |  11 +++
>  gcc/config/i386/i386.md                     | 107 +++++++++++++-----------
> ----
>  gcc/testsuite/gcc.dg/torture/pr85397-1.c    |  29 ++++++++
>  gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c |   4 +-
>  gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c |   4 +-
>  5 files changed, 92 insertions(+), 63 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/torture/pr85397-1.c
> 
> diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
> index c7f9b4551b3..c45d22cae98 100644
> --- a/gcc/config/i386/i386.h
> +++ b/gcc/config/i386/i386.h
> @@ -1943,6 +1943,17 @@ do {
> 		\
>     between pointers and any other objects of this machine mode.  */
>  #define Pmode (ix86_pmode == PMODE_DI ? DImode : SImode)
> 
> +/* Supply a definition of STACK_SAVEAREA_MODE for emit_stack_save.
> +   NONLOCAL needs space to save both shadow stack and stack pointers.
> +
> +   FIXME: We only need to save and restore stack pointer in ptr_mode.
> +   But expand_builtin_setjmp_setup and expand_builtin_longjmp use Pmode
> +   to save and restore stack pointer.  See
> +   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84150
> + */
> +#define STACK_SAVEAREA_MODE(LEVEL)			\
> +  ((LEVEL) == SAVE_NONLOCAL ? (TARGET_64BIT ? TImode : DImode) :
> Pmode)
> +
>  /* Specify the machine mode that bounds have.  */
>  #define BNDmode (ix86_pmode == PMODE_DI ? BND64mode :
> BND32mode)
> 
> diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> index 352212094ec..841d0a77ecc 100644
> --- a/gcc/config/i386/i386.md
> +++ b/gcc/config/i386/i386.md
> @@ -18485,29 +18485,6 @@
>    "* return output_probe_stack_range (operands[0], operands[2]);"
>    [(set_attr "type" "multi")])
> 
> -/* Additional processing for builtin_setjmp.  Store the shadow stack pointer
> -   as a forth element in jmpbuf.  */
> -(define_expand "builtin_setjmp_setup"
> -  [(match_operand 0 "address_operand")]
> -  "TARGET_SHSTK"
> -{
> -  if (flag_cf_protection & CF_RETURN)
> -    {
> -      rtx mem, reg_ssp;
> -
> -      mem = gen_rtx_MEM (word_mode,
> -			 plus_constant (Pmode, operands[0],
> -					3 * GET_MODE_SIZE (ptr_mode)));
> -      reg_ssp = gen_reg_rtx (word_mode);
> -      emit_insn (gen_rtx_SET (reg_ssp, const0_rtx));
> -      emit_insn ((word_mode == SImode)
> -		 ? gen_rdsspsi (reg_ssp)
> -		 : gen_rdsspdi (reg_ssp));
> -      emit_move_insn (mem, reg_ssp);
> -    }
> -  DONE;
> -})
> -
>  (define_expand "builtin_setjmp_receiver"
>    [(label_ref (match_operand 0))]
>    "!TARGET_64BIT && flag_pic"
> @@ -18528,19 +18505,46 @@
>    DONE;
>  })
> 
> -(define_expand "builtin_longjmp"
> -  [(match_operand 0 "address_operand")]
> -  "TARGET_SHSTK"
> +(define_expand "save_stack_nonlocal"
> +  [(set (match_operand 0 "memory_operand")
> +        (match_operand 1 "register_operand"))]
> +  ""
>  {
> -  rtx fp, lab, stack;
> -  rtx flags, jump, noadj_label, inc_label, loop_label;
> -  rtx reg_adj, reg_ssp, mem_buf, tmp, clob;
> -  machine_mode sa_mode = STACK_SAVEAREA_MODE (SAVE_NONLOCAL);
> +  rtx stack_slot;
> +  if (TARGET_SHSTK && (flag_cf_protection & CF_RETURN))
> +    {
> +      /* Copy shadow stack pointer to the first slot and stack ppointer
> +	 to the second slot.  */
> +      rtx ssp_slot = adjust_address (operands[0], word_mode, 0);
> +      stack_slot = adjust_address (operands[0], Pmode, UNITS_PER_WORD);
> +      rtx ssp = gen_reg_rtx (word_mode);
> +      emit_insn ((word_mode == SImode)
> +		 ? gen_rdsspsi (ssp)
> +		 : gen_rdsspdi (ssp));
> +      emit_move_insn (ssp_slot, ssp);
> +    }
> +  else
> +    stack_slot = adjust_address (operands[0], Pmode, 0);
> +  emit_move_insn (stack_slot, operands[1]);
> +  DONE;
> +})
> 
> -  /* Adjust the shadow stack pointer (ssp) to the value saved in the
> -     jmp_buf.  The saving was done in the builtin_setjmp_setup.  */
> -  if (flag_cf_protection & CF_RETURN)
> +(define_expand "restore_stack_nonlocal"
> +  [(set (match_operand 0 "register_operand" "")
> +	(match_operand 1 "memory_operand" ""))]
> +  ""
> +{
> +  rtx stack_slot;
> +  if (TARGET_SHSTK && (flag_cf_protection & CF_RETURN))
>      {
> +      /* Restore shadow stack pointer from the first slot and stack
> +	 pointer from the second slot.  */
> +      rtx ssp_slot = adjust_address (operands[1], word_mode, 0);
> +      stack_slot = adjust_address (operands[1], Pmode, UNITS_PER_WORD);
> +
> +      rtx flags, jump, noadj_label, inc_label, loop_label;
> +      rtx reg_adj, reg_ssp, tmp, clob;
> +
>        /* Get the current shadow stack pointer.  The code below will check if
>  	 SHSTK feature is enabled.  If it is not enabled the RDSSP instruction
>  	 is a NOP.  */
> @@ -18549,13 +18553,11 @@
>        emit_insn ((word_mode == SImode)
>  		 ? gen_rdsspsi (reg_ssp)
>  		 : gen_rdsspdi (reg_ssp));
> -      mem_buf = gen_rtx_MEM (word_mode,
> -			     plus_constant (Pmode, operands[0],
> -					    3 * GET_MODE_SIZE (ptr_mode)));
> 
>        /* Compare through substraction the saved and the current ssp to
> decide
>  	 if ssp has to be adjusted.  */
> -      tmp = gen_rtx_SET (reg_ssp, gen_rtx_MINUS (word_mode, reg_ssp,
> mem_buf));
> +      tmp = gen_rtx_SET (reg_ssp, gen_rtx_MINUS (word_mode, reg_ssp,
> +						 ssp_slot));
>        clob = gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (CCmode,
> FLAGS_REG));
>        tmp = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, tmp, clob));
>        emit_insn (tmp);
> @@ -18595,14 +18597,17 @@
>        jump = emit_jump_insn (gen_rtx_SET (pc_rtx, tmp));
>        JUMP_LABEL (jump) = inc_label;
> 
> +      rtx reg_255 = gen_reg_rtx (word_mode);
> +      emit_move_insn (reg_255, GEN_INT (255));
> +
>        /* Adjust the ssp in a loop.  */
>        loop_label = gen_label_rtx ();
>        emit_label (loop_label);
>        LABEL_NUSES (loop_label) = 1;
> 
>        emit_insn ((word_mode == SImode)
> -		 ? gen_incsspsi (reg_ssp)
> -		 : gen_incsspdi (reg_ssp));
> +		 ? gen_incsspsi (reg_255)
> +		 : gen_incsspdi (reg_255));
>        tmp = gen_rtx_SET (reg_adj, gen_rtx_MINUS (ptr_mode,
>  						 reg_adj,
>  						 GEN_INT (255)));
> @@ -18631,26 +18636,10 @@
>        emit_label (noadj_label);
>        LABEL_NUSES (noadj_label) = 1;
>      }
> -
> -  /* This code is the same as in expand_buildin_longjmp.  */
> -  fp = gen_rtx_MEM (ptr_mode, operands[0]);
> -  lab = gen_rtx_MEM (ptr_mode, plus_constant (Pmode, operands[0],
> -					      GET_MODE_SIZE (ptr_mode)));
> -  stack = gen_rtx_MEM (sa_mode, plus_constant (Pmode, operands[0],
> -					       2 * GET_MODE_SIZE (ptr_mode)));
> -  lab = copy_to_reg (lab);
> -
> -  emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
> -  emit_clobber (gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx));
> -
> -  if (GET_MODE (fp) != Pmode)
> -    fp = convert_to_mode (Pmode, fp, 1);
> -  emit_move_insn (hard_frame_pointer_rtx, fp);
> -  emit_stack_restore (SAVE_NONLOCAL, stack);
> -
> -  emit_use (hard_frame_pointer_rtx);
> -  emit_use (stack_pointer_rtx);
> -  emit_indirect_jump (lab);
> +  else
> +    stack_slot = adjust_address (operands[1], Pmode, 0);
> +  emit_move_insn (operands[0], stack_slot);
> +  DONE;
>  })
> 
> 
> diff --git a/gcc/testsuite/gcc.dg/torture/pr85397-1.c
> b/gcc/testsuite/gcc.dg/torture/pr85397-1.c
> new file mode 100644
> index 00000000000..65085240266
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/torture/pr85397-1.c
> @@ -0,0 +1,29 @@
> +/* { dg-do run { target i?86-*-* x86_64-*-* } } */
> +/* { dg-require-effective-target cet } */
> +/* { dg-additional-options "-fcf-protection -mcet" } */
> +
> +#define DEPTH 1000
> +
> +int
> +x(int a)
> +{
> +  __label__ xlab;
> +  void y(int a)
> +    {
> +      if (a==0)
> +	goto xlab;
> +      y (a-1);
> +    }
> +  y (a);
> + xlab:;
> +  return a;
> +}
> +
> +int
> +main ()
> +{
> +  if (x (DEPTH) != DEPTH)
> +    __builtin_abort ();
> +
> +  return 0;
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c
> b/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c
> index 8410ff99b47..87fe2e6dc67 100644
> --- a/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c
> +++ b/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c
> @@ -2,8 +2,8 @@
>  /* { dg-require-effective-target maybe_x32 } */
>  /* { dg-options "-O -maddress-mode=short -fcf-protection -mcet -mx32" }
> */
>  /* { dg-final { scan-assembler-times "endbr64" 2 } } */
> -/* { dg-final { scan-assembler-times "movq\t.*buf\\+12" 1 } } */
> -/* { dg-final { scan-assembler-times "subq\tbuf\\+12" 1 } } */
> +/* { dg-final { scan-assembler-times "movq\t.*buf\\+8" 1 } } */
> +/* { dg-final { scan-assembler-times "subq\tbuf\\+8" 1 } } */
>  /* { dg-final { scan-assembler-times "shrl\t\\\$3," 1 } } */
>  /* { dg-final { scan-assembler-times "rdsspq" 2 } } */
>  /* { dg-final { scan-assembler-times "incsspq" 2 } } */
> diff --git a/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c
> b/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c
> index ce111631ac1..b3866d52946 100644
> --- a/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c
> +++ b/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c
> @@ -1,8 +1,8 @@
>  /* { dg-do compile { target { ! ia32 } } } */
>  /* { dg-options "-O -maddress-mode=long -fcf-protection -mcet -mx32" }
> */
>  /* { dg-final { scan-assembler-times "endbr64" 2 } } */
> -/* { dg-final { scan-assembler-times "movq\t.*buf\\+12" 1 } } */
> -/* { dg-final { scan-assembler-times "subq\tbuf\\+12" 1 } } */
> +/* { dg-final { scan-assembler-times "movq\t.*buf\\+16" 1 } } */
> +/* { dg-final { scan-assembler-times "subq\tbuf\\+16" 1 } } */
>  /* { dg-final { scan-assembler-times "shrl\t\\\$3," 1 } } */
>  /* { dg-final { scan-assembler-times "rdsspq" 2 } } */
>  /* { dg-final { scan-assembler-times "incsspq" 2 } } */
> --
> 2.14.3

On Thu, Apr 19, 2018 at 8:51 AM, Tsimbalist, Igor V
<igor.v.tsimbalist@intel.com> wrote:
>> -----Original Message-----
>> From: Lu, Hongjiu
>> Sent: Sunday, April 15, 2018 12:58 PM
>> To: gcc-patches@gcc.gnu.org
>> Cc: Uros Bizjak <ubizjak@gmail.com>; Tsimbalist, Igor V
>> <igor.v.tsimbalist@intel.com>
>> Subject: [PATCH] i386: Add save_stack_nonlocal and restore_stack_nonlocal
>>
>> Define STACK_SAVEAREA_MODE to hold both shadow stack and stack
>> pointers.
>> Replace builtin_setjmp_setup and builtin_longjmp with save_stack_nonlocal
>> and restore_stack_nonlocal to support both builtin setjmp/longjmp as well
>> as non-local goto in nested functions.
>>
>> OK for trunk?
>
> OK.
>

This is what I checked in.  TARGET_SHSTK is no longer checked for
-fcf-protection.