Add Windows Control Flow Guard checks (/guard:cf).

Summary:
A new function pass (Transforms/CFGuard/CFGuard.cpp) inserts CFGuard checks on
indirect function calls, using either the check mechanism (X86, ARM, AArch64) or
or the dispatch mechanism (X86-64). The check mechanism requires a new calling
convention for the supported targets. The dispatch mechanism adds the target as
an operand bundle, which is processed by SelectionDAG. Another pass
(CodeGen/CFGuardLongjmp.cpp) identifies and emits valid longjmp targets, as
required by /guard:cf. This feature is enabled using the `cfguard` CC1 option.

Reviewers: thakis, rnk, theraven, pcc

Subscribers: ychen, hans, metalcanine, dmajor, tomrittervg, alex, mehdi_amini, mgorny, javed.absar, kristof.beyls, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D65761

1 files changed, 8 insertions, 6 deletions

diff --git a/clang/test/CodeGen/cfguardtable.c b/clang/test/CodeGen/cfguardtable.c
index 96492926129..05284f6d23a 100644
--- a/clang/test/CodeGen/cfguardtable.c
+++ b/clang/test/CodeGen/cfguardtable.c
@@ -1,6 +1,8 @@
-// RUN: %clang_cc1 -cfguard -emit-llvm %s -o - | FileCheck %s
-
-void f() {}
-
-// Check that the cfguardtable metadata flag gets set on the module.
-// CHECK: !"cfguardtable", i32 1}
+// RUN: %clang_cc1 -cfguard-no-checks -emit-llvm %s -o - | FileCheck %s -check-prefix=CFGUARDNOCHECKS

+// RUN: %clang_cc1 -cfguard -emit-llvm %s -o - | FileCheck %s -check-prefix=CFGUARD

+

+void f() {}

+

+// Check that the cfguard metadata flag gets correctly set on the module.

+// CFGUARDNOCHECKS: !"cfguard", i32 1}

+// CFGUARD: !"cfguard", i32 2}