bpf: bump maximum frame size limit to 32767 bytes

This commit bumps the maximum stack frame size allowed for BPF
functions to the maximum possible value.

Tested in x86_64-linux-gnu host and target bpf-unknown-none.

gcc/ChangeLog

	* config/bpf/bpf.opt (mframe-limit): Set default to 32767.

gcc/testsuite/ChangeLog

	* gcc.target/bpf/frame-limit-1.c: New test.
	* gcc.target/bpf/frame-limit-2.c: Likewise.

3 files changed, 35 insertions, 1 deletions

diff --git a/gcc/config/bpf/bpf.opt b/gcc/config/bpf/bpf.opt
index 8e240d3..efa0380 100644
--- a/gcc/config/bpf/bpf.opt
+++ b/gcc/config/bpf/bpf.opt
@@ -38,7 +38,7 @@ Target RejectNegative InverseMask(BIG_ENDIAN)
 Generate little-endian eBPF.
 
 mframe-limit=
-Target Joined RejectNegative UInteger IntegerRange(0, 32767) Var(bpf_frame_limit) Init(512)
+Target Joined RejectNegative UInteger IntegerRange(0, 32767) Var(bpf_frame_limit) Init(32767)
 Set a hard limit for the size of each stack frame, in bytes.
 
 mco-re
diff --git a/gcc/testsuite/gcc.target/bpf/frame-limit-1.c b/gcc/testsuite/gcc.target/bpf/frame-limit-1.c
new file mode 100644
index 0000000..7843e04
--- /dev/null
+++ b/gcc/testsuite/gcc.target/bpf/frame-limit-1.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O0" } */
+
+/* The stack frame size is limited to 32767 bytes.  */
+
+int
+foo ()
+{
+  long data[4095];
+  return 0;
+}
+
+int
+bar ()
+{
+  long data[4096];
+  return 0;
+} /* { dg-error "stack limit" } */
diff --git a/gcc/testsuite/gcc.target/bpf/frame-limit-2.c b/gcc/testsuite/gcc.target/bpf/frame-limit-2.c
new file mode 100644
index 0000000..57f82e0
--- /dev/null
+++ b/gcc/testsuite/gcc.target/bpf/frame-limit-2.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O0 -mframe-limit=256" } */
+
+int
+foo ()
+{
+  long data[32];
+  return 0;
+}
+
+int
+bar ()
+{
+  long data[33];
+  return 0;
+} /* { dg-error "stack limit" } */