driver: -fhardened and -z lazy/-z norelro [PR117739]

As the manual states, using "-fhardened -fstack-protector" will produce
a warning because -fhardened wants to enable -fstack-protector-strong,
but it can't since it's been overriden by the weaker -fstack-protector.

-fhardened also attempts to enable -Wl,-z,relro,-z,now.  By the same
logic as above, "-fhardened -z norelro" or "-fhardened -z lazy" should
produce the same warning.  But we don't detect this combination, so
this patch fixes it.  I also renamed a variable to better reflect its
purpose.

Also don't check warn_hardened in process_command, since it's always
true there.

Also tweak wording in the manual as Jon Wakely suggested on IRC.

	PR driver/117739

gcc/ChangeLog:

	* doc/invoke.texi: Tweak wording for -Whardened.
	* gcc.cc (driver_handle_option): If -z lazy or -z norelro was
	specified, don't enable linker hardening.
	(process_command): Don't check warn_hardened.

gcc/testsuite/ChangeLog:

	* c-c++-common/fhardened-16.c: New test.
	* c-c++-common/fhardened-17.c: New test.
	* c-c++-common/fhardened-18.c: New test.
	* c-c++-common/fhardened-19.c: New test.
	* c-c++-common/fhardened-20.c: New test.
	* c-c++-common/fhardened-21.c: New test.

Reviewed-by: Jakub Jelinek <jakub@redhat.com>

6 files changed, 30 insertions, 0 deletions

diff --git a/gcc/testsuite/c-c++-common/fhardened-16.c b/gcc/testsuite/c-c++-common/fhardened-16.c
new file mode 100644
index 0000000..7a50ad0
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/fhardened-16.c
@@ -0,0 +1,5 @@
+/* PR driver/117739 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-fhardened -O -Wl,-z,lazy -Whardened" } */
+
+/* { dg-warning "linker hardening options not enabled" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/c-c++-common/fhardened-17.c b/gcc/testsuite/c-c++-common/fhardened-17.c
new file mode 100644
index 0000000..acef8c6
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/fhardened-17.c
@@ -0,0 +1,5 @@
+/* PR driver/117739 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-fhardened -O -z lazy -Whardened" } */
+
+/* { dg-warning "linker hardening options not enabled" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/c-c++-common/fhardened-18.c b/gcc/testsuite/c-c++-common/fhardened-18.c
new file mode 100644
index 0000000..1a9a34b
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/fhardened-18.c
@@ -0,0 +1,5 @@
+/* PR driver/117739 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-Wl,-z,lazy -fhardened -O -Whardened" } */
+
+/* { dg-warning "linker hardening options not enabled" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/c-c++-common/fhardened-19.c b/gcc/testsuite/c-c++-common/fhardened-19.c
new file mode 100644
index 0000000..a871702
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/fhardened-19.c
@@ -0,0 +1,5 @@
+/* PR driver/117739 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-z lazy -fhardened -O -Whardened" } */
+
+/* { dg-warning "linker hardening options not enabled" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/c-c++-common/fhardened-20.c b/gcc/testsuite/c-c++-common/fhardened-20.c
new file mode 100644
index 0000000..c9f2d89
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/fhardened-20.c
@@ -0,0 +1,5 @@
+/* PR driver/117739 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-fhardened -O -Wl,-z,norelro -Whardened" } */
+
+/* { dg-warning "linker hardening options not enabled" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/c-c++-common/fhardened-21.c b/gcc/testsuite/c-c++-common/fhardened-21.c
new file mode 100644
index 0000000..07b7ee1
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/fhardened-21.c
@@ -0,0 +1,5 @@
+/* PR driver/117739 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-fhardened -O -z norelro -Whardened" } */
+
+/* { dg-warning "linker hardening options not enabled" "" { target *-*-* } 0 } */