Patchwork [gccgo] Test for -fsplit-stack and alloca

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Submitter Ian Taylor
Date Sept. 17, 2010, 11:26 p.m.
Message ID <mcriq24kl43.fsf@google.com>
Download mbox | patch
Permalink /patch/65115/
State New
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Comments

Ian Taylor - Sept. 17, 2010, 11:26 p.m.
I forgot to commit this with the last patch.  This is a test case for
-fsplit-stack with alloca.  Committed to gccgo branch.

Ian

Patch

Index: gcc/testsuite/gcc.dg/split-4.c
===================================================================
--- gcc/testsuite/gcc.dg/split-4.c	(revision 0)
+++ gcc/testsuite/gcc.dg/split-4.c	(revision 0)
@@ -0,0 +1,65 @@ 
+/* This test needs to use setrlimit to set the stack size, so it can
+   only run on Unix.  */
+/* { dg-do run { target *-*-linux* *-*-solaris* *-*-darwin* } } */
+/* { dg-require-effective-target split_stack } */
+/* { dg-options "-fsplit-stack" } */
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/resource.h>
+
+/* Use a noinline function to ensure that the buffer is not removed
+   from the stack.  */
+static void use_buffer (char *buf, size_t) __attribute__ ((noinline));
+static void
+use_buffer (char *buf, size_t c)
+{
+  memset (buf, '\0', c);
+}
+
+/* Each recursive call uses 10 * i bytes.  We call it 1000 times,
+   using a total of 5,000,000 bytes.  If -fsplit-stack is not working,
+   that will overflow our stack limit.  */
+
+static void
+down1 (int i)
+{
+  char buf[10 * i];
+
+  if (i > 0)
+    {
+      use_buffer (buf, 10 * i);
+      down1 (i - 1);
+    }
+}
+
+/* Same thing, using alloca.  */
+
+static void
+down2 (int i)
+{
+  char *buf = alloca (10 * i);
+
+  if (i > 0)
+    {
+      use_buffer (buf, 10 * i);
+      down2 (i - 1);
+    }
+}
+
+int
+main (void)
+{
+  struct rlimit r;
+
+  /* We set a stack limit because we are usually invoked via make, and
+     make sets the stack limit to be as large as possible.  */
+  r.rlim_cur = 8192 * 1024;
+  r.rlim_max = 8192 * 1024;
+  if (setrlimit (RLIMIT_STACK, &r) != 0)
+    abort ();
+  down1 (1000);
+  down2 (1000);
+  return 0;
+}