Currently when -fcf-protection=return and zcmp are enabled this code is
generated:
sspush ra
cm.push {ra, s0-s1}, -32
..
cm.popret {ra, s0-s1}, 32
riscv_expand_epilogue will skip emitting sspopchk when cm.popret is
emitted. After this patch we will no longer emit cm.popret and instead
use cm.pop + sspopchk + a regular return:
sspush ra
cm.push {ra, s0-s1}, -32
..
cm.pop {ra, s0-s1}, 32
sspopchk ra
jr ra
Regtested for rv32g & rv64g.
PR target/125217
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_gen_multi_pop_insn): Rename variable.
(riscv_expand_epilogue): Don't emit cm.popret with shadow stack.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/ssp-zcmp.c: New test.
Signed-off-by: Michiel Derhaeg <[email protected]>
---
gcc/config/riscv/riscv.cc | 24 ++++++-------
gcc/testsuite/gcc.target/riscv/ssp-zcmp.c | 42 +++++++++++++++++++++++
2 files changed, 54 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/ssp-zcmp.c
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 108f1c4b3cf..681b816d248 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -10123,13 +10123,13 @@ riscv_adjust_libcall_cfi_epilogue ()
}
static void
-riscv_gen_multi_pop_insn (bool use_multi_pop_normal, unsigned mask,
+riscv_gen_multi_pop_insn (bool use_popret, unsigned mask,
unsigned multipop_size)
{
rtx insn;
unsigned regs_count = riscv_multi_push_regs_count (mask);
- if (!use_multi_pop_normal)
+ if (!use_popret)
insn = emit_insn (
riscv_gen_multi_push_pop_insn (POP_IDX, multipop_size, regs_count));
else
@@ -10158,11 +10158,8 @@ riscv_expand_epilogue (int style)
unsigned fmask = frame->fmask;
unsigned mask_fprs_push = 0;
poly_int64 step2 = 0;
- bool use_multi_pop_normal
- = ((style == NORMAL_RETURN) && riscv_use_multi_push (frame));
- bool use_multi_pop_sibcall
- = ((style == SIBCALL_RETURN) && riscv_use_multi_push (frame));
- bool use_multi_pop = use_multi_pop_normal || use_multi_pop_sibcall;
+ bool use_multi_pop = ((style == NORMAL_RETURN) || (style == SIBCALL_RETURN))
+ && riscv_use_multi_push (frame);
bool use_restore_libcall
= !use_multi_pop
@@ -10430,9 +10427,10 @@ riscv_expand_epilogue (int style)
/* Undo the above fib. */
frame->mask = mask;
frame->fmask = fmask;
- riscv_gen_multi_pop_insn (use_multi_pop_normal, frame->mask,
- multipop_size);
- if (use_multi_pop_normal)
+ bool use_popret = style == NORMAL_RETURN
+ && !need_shadow_stack_push_pop_p ();
+ riscv_gen_multi_pop_insn (use_popret, frame->mask, multipop_size);
+ if (use_popret)
return;
}
else if (use_restore_libcall)
@@ -10456,7 +10454,8 @@ riscv_expand_epilogue (int style)
{
if (BITSET_P (cfun->machine->frame.mask, RETURN_ADDR_REGNUM)
&& style != SIBCALL_RETURN
- && !cfun->machine->interrupt_handler_p)
+ && !cfun->machine->interrupt_handler_p
+ && !use_multi_pop)
emit_insn (gen_sspopchk (Pmode, t0));
else
emit_insn (gen_sspopchk (Pmode, ra));
@@ -10483,7 +10482,8 @@ riscv_expand_epilogue (int style)
if (need_shadow_stack_push_pop_p ()
&& !((style == EXCEPTION_RETURN) && crtl->calls_eh_return)
&& BITSET_P (cfun->machine->frame.mask, RETURN_ADDR_REGNUM)
- && !cfun->machine->interrupt_handler_p)
+ && !cfun->machine->interrupt_handler_p
+ && !use_multi_pop)
emit_jump_insn (gen_simple_return_internal (t0));
else
emit_jump_insn (gen_simple_return_internal (ra));
diff --git a/gcc/testsuite/gcc.target/riscv/ssp-zcmp.c
b/gcc/testsuite/gcc.target/riscv/ssp-zcmp.c
new file mode 100644
index 00000000000..096f1e50a58
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/ssp-zcmp.c
@@ -0,0 +1,42 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -march=rv32g_zcmp_zcmop_zicfiss -mabi=ilp32d
-fcf-protection=return" } */
+/* { dg-skip-if "needs -Os" { *-*-* } { "-O0" "-O1" "-O2" "-O3" "-Og" "-Oz" }
{ "" } } */
+/* { dg-final { check-function-bodies "**" "" } } */
+/* { dg-final { scan-assembler-not {cm\.popret} } } */
+
+int printf (const char *, ...);
+
+/*
+** printSomething:
+** sspush ra
+** ...
+** cm\.push \{ra, s0-s2\}, -32
+** ...
+** cm\.pop \{ra, s0-s2\}, 32
+** sspopchk ra
+** jr ra
+** ...
+*/
+int printSomething (int arr[], int len) {
+ for (int i = 0; i < len; i++)
+ printf ("Val[%d]: %d\n", i, arr[i]);
+ return len;
+}
+
+extern int sibcallee (int);
+extern void other (void);
+
+/*
+** sibcaller:
+** sspush ra
+** cm\.push \{ra\}, -32
+** ...
+** cm\.pop \{ra\}, 32
+** ...
+** sspopchk ra
+** tail sibcallee
+*/
+int sibcaller (int x) {
+ other ();
+ return sibcallee (x + 1);
+}
--
2.37.1
