When the SHSTK feature is not available or not enabled, RDSSP is a NOP,
always save and restore shadow stack pointer to support compiling source
codes, containing __builtin_setjmp and __builtin_longjmp, with different
-fcf-protection options.
PR target/98997
* config/i386/i386.md (save_stack_nonlocal): Always save shadow
stack pointer.
(restore_stack_nonlocal): Always restore shadow stack pointer.
(@rdssp<mode>): Make it unconditional.
(@incssp<mode>): Likewise.
---
gcc/config/i386/i386.md | 150 ++++++++++++++++++----------------------
1 file changed, 68 insertions(+), 82 deletions(-)
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index b60784a2908..2510bd8a73d 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -19398,21 +19398,16 @@ (define_expand "save_stack_nonlocal"
(match_operand 1 "register_operand"))]
""
{
- rtx stack_slot;
-
- if (flag_cf_protection & CF_RETURN)
- {
- /* Copy shadow stack pointer to the first slot
- and stack pointer 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 reg_ssp = force_reg (word_mode, const0_rtx);
- emit_insn (gen_rdssp (word_mode, reg_ssp, reg_ssp));
- emit_move_insn (ssp_slot, reg_ssp);
- }
- else
- stack_slot = adjust_address (operands[0], Pmode, 0);
+ /* Copy shadow stack pointer to the first slot and stack pointer to
+ the second slot. */
+ rtx ssp_slot = adjust_address (operands[0], word_mode, 0);
+ rtx stack_slot = adjust_address (operands[0], Pmode, UNITS_PER_WORD);
+
+ /* If the SHSTK feature is not available or not enabled, the RDSSP
+ instruction is a NOP and REG_SSP is 0. */
+ rtx reg_ssp = force_reg (word_mode, const0_rtx);
+ emit_insn (gen_rdssp (word_mode, reg_ssp, reg_ssp));
+ emit_move_insn (ssp_slot, reg_ssp);
emit_move_insn (stack_slot, operands[1]);
DONE;
})
@@ -19422,72 +19417,63 @@ (define_expand "restore_stack_nonlocal"
(match_operand 1 "memory_operand" ""))]
""
{
- rtx stack_slot;
+ /* 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);
+ rtx stack_slot = adjust_address (operands[1], Pmode, UNITS_PER_WORD);
- if (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);
-
- /* 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. */
- rtx reg_ssp = force_reg (word_mode, const0_rtx);
- emit_insn (gen_rdssp (word_mode, reg_ssp, reg_ssp));
-
- /* Compare through subtraction the saved and the current ssp
- to decide if ssp has to be adjusted. */
- reg_ssp = expand_simple_binop (word_mode, MINUS,
- reg_ssp, ssp_slot,
- reg_ssp, 1, OPTAB_DIRECT);
-
- /* Compare and jump over adjustment code. */
- rtx noadj_label = gen_label_rtx ();
- emit_cmp_and_jump_insns (reg_ssp, const0_rtx, EQ, NULL_RTX,
- word_mode, 1, noadj_label);
-
- /* Compute the number of frames to adjust. */
- rtx reg_adj = gen_lowpart (ptr_mode, reg_ssp);
- rtx reg_adj_neg = expand_simple_unop (ptr_mode, NEG, reg_adj,
- NULL_RTX, 1);
-
- reg_adj = expand_simple_binop (ptr_mode, LSHIFTRT, reg_adj_neg,
- GEN_INT (exact_log2 (UNITS_PER_WORD)),
- reg_adj, 1, OPTAB_DIRECT);
-
- /* Check if number of frames <= 255 so no loop is needed. */
- rtx inc_label = gen_label_rtx ();
- emit_cmp_and_jump_insns (reg_adj, GEN_INT (255), LEU, NULL_RTX,
- ptr_mode, 1, inc_label);
-
- /* Adjust the ssp in a loop. */
- rtx loop_label = gen_label_rtx ();
- emit_label (loop_label);
- LABEL_NUSES (loop_label) = 1;
-
- rtx reg_255 = force_reg (word_mode, GEN_INT (255));
- emit_insn (gen_incssp (word_mode, reg_255));
-
- reg_adj = expand_simple_binop (ptr_mode, MINUS,
- reg_adj, GEN_INT (255),
- reg_adj, 1, OPTAB_DIRECT);
-
- /* Compare and jump to the loop label. */
- emit_cmp_and_jump_insns (reg_adj, GEN_INT (255), GTU, NULL_RTX,
- ptr_mode, 1, loop_label);
-
- emit_label (inc_label);
- LABEL_NUSES (inc_label) = 1;
-
- emit_insn (gen_incssp (word_mode, reg_ssp));
-
- emit_label (noadj_label);
- LABEL_NUSES (noadj_label) = 1;
- }
- else
- stack_slot = adjust_address (operands[1], Pmode, 0);
+ /* If the SHSTK feature is not available or not enabled, the RDSSP
+ instruction is a NOP and REG_SSP is 0. */
+ rtx reg_ssp = force_reg (word_mode, const0_rtx);
+ emit_insn (gen_rdssp (word_mode, reg_ssp, reg_ssp));
+
+ /* Compare through subtraction the saved and the current ssp to
+ decide if ssp has to be adjusted. */
+ reg_ssp = expand_simple_binop (word_mode, MINUS, reg_ssp, ssp_slot,
+ reg_ssp, 1, OPTAB_DIRECT);
+
+ /* Compare and jump over adjustment code. */
+ rtx noadj_label = gen_label_rtx ();
+ emit_cmp_and_jump_insns (reg_ssp, const0_rtx, EQ, NULL_RTX,
+ word_mode, 1, noadj_label);
+
+ /* Compute the number of frames to adjust. */
+ rtx reg_adj = gen_lowpart (ptr_mode, reg_ssp);
+ rtx reg_adj_neg = expand_simple_unop (ptr_mode, NEG, reg_adj,
+ NULL_RTX, 1);
+
+ reg_adj = expand_simple_binop (ptr_mode, LSHIFTRT, reg_adj_neg,
+ GEN_INT (exact_log2 (UNITS_PER_WORD)),
+ reg_adj, 1, OPTAB_DIRECT);
+
+ /* Check if number of frames <= 255 so no loop is needed. */
+ rtx inc_label = gen_label_rtx ();
+ emit_cmp_and_jump_insns (reg_adj, GEN_INT (255), LEU, NULL_RTX,
+ ptr_mode, 1, inc_label);
+
+ /* Adjust the ssp in a loop. */
+ rtx loop_label = gen_label_rtx ();
+ emit_label (loop_label);
+ LABEL_NUSES (loop_label) = 1;
+
+ rtx reg_255 = force_reg (word_mode, GEN_INT (255));
+ emit_insn (gen_incssp (word_mode, reg_255));
+
+ reg_adj = expand_simple_binop (ptr_mode, MINUS,
+ reg_adj, GEN_INT (255),
+ reg_adj, 1, OPTAB_DIRECT);
+
+ /* Compare and jump to the loop label. */
+ emit_cmp_and_jump_insns (reg_adj, GEN_INT (255), GTU, NULL_RTX,
+ ptr_mode, 1, loop_label);
+
+ emit_label (inc_label);
+ LABEL_NUSES (inc_label) = 1;
+
+ emit_insn (gen_incssp (word_mode, reg_ssp));
+
+ emit_label (noadj_label);
+ LABEL_NUSES (noadj_label) = 1;
emit_move_insn (operands[0], stack_slot);
DONE;
})
@@ -21455,7 +21441,7 @@ (define_insn "@rdssp<mode>"
[(set (match_operand:SWI48 0 "register_operand" "=r")
(unspec_volatile:SWI48 [(match_operand:SWI48 1 "register_operand" "0")]
UNSPECV_NOP_RDSSP))]
- "TARGET_SHSTK || (flag_cf_protection & CF_RETURN)"
+ ""
"rdssp<mskmodesuffix>\t%0"
[(set_attr "length" "6")
(set_attr "type" "other")])
@@ -21463,7 +21449,7 @@ (define_insn "@rdssp<mode>"
(define_insn "@incssp<mode>"
[(unspec_volatile [(match_operand:SWI48 0 "register_operand" "r")]
UNSPECV_INCSSP)]
- "TARGET_SHSTK || (flag_cf_protection & CF_RETURN)"
+ ""
"incssp<mskmodesuffix>\t%0"
[(set_attr "length" "4")
(set_attr "type" "other")])
--
2.29.2
