diff mbox series

[Committed] IBM Z: stack clash prot: add missing updates of last_probe_offset

Message ID 20200514062127.14234-1-krebbel@linux.ibm.com
State New
Headers show
Series [Committed] IBM Z: stack clash prot: add missing updates of last_probe_offset | expand

Commit Message

Andreas Krebbel May 14, 2020, 6:21 a.m. UTC 
After emitting probes in a loop last_probe_offset needs to be updated.
Not doing this usually assumes a too low distance to the last access
when emitting the remainder leading to stack probes being omitted.

Bootstrapped and regression tested on s390x

Committed to mainline

gcc/ChangeLog:

2020-05-14  Andreas Krebbel  <krebbel@linux.ibm.com>

	* config/s390/s390.c (allocate_stack_space): Add missing updates
	of last_probe_offset.

gcc/testsuite/ChangeLog:

2020-05-14  Andreas Krebbel  <krebbel@linux.ibm.com>

	* gcc.target/s390/stack-clash-1.c: New test.
---
 gcc/ChangeLog                                 |  5 +++++
 gcc/config/s390/s390.c                        |  3 +++
 gcc/testsuite/ChangeLog                       |  4 ++++
 gcc/testsuite/gcc.target/s390/stack-clash-1.c | 17 +++++++++++++++++
 4 files changed, 29 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/s390/stack-clash-1.c
diff mbox series

Patch

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0b326ee09e8..51d3e425ad5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@ 
+2020-05-14  Andreas Krebbel  <krebbel@linux.ibm.com>
+
+	* config/s390/s390.c (allocate_stack_space): Add missing updates
+	of last_probe_offset.
+
 2020-05-14  Andreas Krebbel  <krebbel@linux.ibm.com>
 
 	* config/s390/s390.md ("allocate_stack"): Call
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 18332271ed7..b4897256af5 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -10996,6 +10996,8 @@  allocate_stack_space (rtx size, HOST_WIDE_INT last_probe_offset,
 						       stack_pointer_rtx,
 						       offset));
 		}
+	      if (num_probes > 0)
+		last_probe_offset = INTVAL (offset);
 	      dump_stack_clash_frame_info (PROBE_INLINE, residual != 0);
 	    }
 	  else
@@ -11029,6 +11031,7 @@  allocate_stack_space (rtx size, HOST_WIDE_INT last_probe_offset,
 	      s390_prologue_plus_offset (stack_pointer_rtx, temp_reg,
 					 const0_rtx, true);
 	      temp_reg_clobbered_p = true;
+	      last_probe_offset = INTVAL (offset);
 	      dump_stack_clash_frame_info (PROBE_LOOP, residual != 0);
 	    }
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bb3e4c86adc..8ff0bbcc85b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@ 
+2020-05-14  Andreas Krebbel  <krebbel@linux.ibm.com>
+
+	* gcc.target/s390/stack-clash-1.c: New test.
+
 2020-05-14  Andreas Krebbel  <krebbel@linux.ibm.com>
 
 	* gcc.target/s390/stack-clash-3.c: New test.
diff --git a/gcc/testsuite/gcc.target/s390/stack-clash-1.c b/gcc/testsuite/gcc.target/s390/stack-clash-1.c
new file mode 100644
index 00000000000..3d29cab9446
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/stack-clash-1.c
@@ -0,0 +1,17 @@ 
+/* Make sure a stack probe is emitted also for the remaining bytes
+   after the loop probing the large chunk.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=z9-ec -fstack-clash-protection" } */
+
+void large_stack() {
+  volatile int stack[8000];
+  int i;
+  for (i = 0; i < sizeof(stack) / sizeof(int); ++i)
+    stack[i] = i;
+}
+
+/* We use a compare for the stack probe.  There needs to be one inside
+   a loop and another for the remaining bytes.  */
+/* { dg-final { scan-assembler-times "cg\t" 2 { target lp64 } } } */
+/* { dg-final { scan-assembler-times "c\t" 2 { target { ! lp64 } } } } */