x86: Disallow -mindirect-branch=/-mfunction-return= with -mcmodel=largehjl/indirect/gcc-7-branch/master

Since the thunk function may not be reachable in large code model,
-mcmodel=large is incompatible with -mindirect-branch=thunk,
-mindirect-branch=thunk-extern, -mfunction-return=thunk and
-mfunction-return=thunk-extern.  Issue an error when they are used with
-mcmodel=large.

gcc/

	Backport from mainline
	* config/i386/i386.c (ix86_set_indirect_branch_type): Disallow
	-mcmodel=large with -mindirect-branch=thunk,
	-mindirect-branch=thunk-extern, -mfunction-return=thunk and
	-mfunction-return=thunk-extern.
	* doc/invoke.texi: Document -mcmodel=large is incompatible with
	-mindirect-branch=thunk, -mindirect-branch=thunk-extern,
	-mfunction-return=thunk and -mfunction-return=thunk-extern.

gcc/testsuite/

	Backport from mainline
	* gcc.target/i386/indirect-thunk-10.c: New test.
	* gcc.target/i386/indirect-thunk-8.c: Likewise.
	* gcc.target/i386/indirect-thunk-9.c: Likewise.
	* gcc.target/i386/indirect-thunk-attr-10.c: Likewise.
	* gcc.target/i386/indirect-thunk-attr-11.c: Likewise.
	* gcc.target/i386/indirect-thunk-attr-9.c: Likewise.
	* gcc.target/i386/ret-thunk-17.c: Likewise.
	* gcc.target/i386/ret-thunk-18.c: Likewise.
	* gcc.target/i386/ret-thunk-19.c: Likewise.
	* gcc.target/i386/ret-thunk-20.c: Likewise.
	* gcc.target/i386/ret-thunk-21.c: Likewise.

1 files changed, 8 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-18.c b/gcc/testsuite/gcc.target/i386/ret-thunk-18.c
new file mode 100644
index 00000000000..307019dc242
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/ret-thunk-18.c
@@ -0,0 +1,8 @@
+/* { dg-do compile { target { lp64 } } } */
+/* { dg-options "-O2 -mfunction-return=thunk-extern -mindirect-branch=keep -mcmodel=large" } */
+/* { dg-additional-options "-fPIC" { target fpic } } */
+
+void
+bar (void)
+{ /* { dg-error "'-mfunction-return=thunk-extern' and '-mcmodel=large' are not compatible" } */
+}