Cross-DSO control flow integrity (Clang part).

Clang-side cross-DSO CFI.

* Adds a command line flag -f[no-]sanitize-cfi-cross-dso.
* Links a runtime library when enabled.
* Emits __cfi_slowpath calls is bitset test fails.
* Emits extra hash-based bitsets for external CFI checks.
* Sets a module flag to enable __cfi_check generation during LTO.

This mode does not yet support diagnostics.

llvm-svn: 255694

1 files changed, 45 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/cfi-cross-dso.cpp b/clang/test/CodeGenCXX/cfi-cross-dso.cpp
new file mode 100644
index 00000000000..e7e9f98ce59
--- /dev/null
+++ b/clang/test/CodeGenCXX/cfi-cross-dso.cpp
@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=cfi-vcall -fsanitize-cfi-cross-dso -emit-llvm -o - %s | FileCheck --check-prefix=CHECK --check-prefix=ITANIUM %s
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -fsanitize=cfi-vcall  -fsanitize-cfi-cross-dso -emit-llvm -o - %s | FileCheck --check-prefix=CHECK --check-prefix=MS %s
+
+struct A {
+  A();
+  virtual void f();
+};
+
+A::A() {}
+void A::f() {}
+
+void caller(A* a) {
+  a->f();
+}
+
+namespace {
+struct B {
+  virtual void f();
+};
+
+void B::f() {}
+} // namespace
+
+void g() {
+  B b;
+  b.f();
+}
+
+// MS: @[[B_VTABLE:.*]] = private unnamed_addr constant [2 x i8*] {{.*}}@"\01??_R4B@?A@@6B@"{{.*}}@"\01?f@B@?A@@UEAAXXZ"
+
+// CHECK:   %[[VT:.*]] = load void (%struct.A*)**, void (%struct.A*)***
+// CHECK:   %[[VT2:.*]] = bitcast {{.*}}%[[VT]] to i8*, !nosanitize
+// ITANIUM:   %[[TEST:.*]] = call i1 @llvm.bitset.test(i8* %[[VT2]], metadata !"_ZTS1A"), !nosanitize
+// MS:   %[[TEST:.*]] = call i1 @llvm.bitset.test(i8* %[[VT2]], metadata !"?AUA@@"), !nosanitize
+// CHECK:   br i1 %[[TEST]], label %[[CONT:.*]], label %[[SLOW:.*]], {{.*}} !nosanitize
+// CHECK: [[SLOW]]:
+// ITANIUM:   call void @__cfi_slowpath(i64 7004155349499253778, i8* %[[VT2]]) {{.*}} !nosanitize
+// MS:   call void @__cfi_slowpath(i64 -8005289897957287421, i8* %[[VT2]]) {{.*}} !nosanitize
+// CHECK:   br label %[[CONT]], !nosanitize
+// CHECK: [[CONT]]:
+// CHECK:   call void %{{.*}}(%struct.A* %{{.*}})
+
+// No hash-based bit set entry for (anonymous namespace)::B
+// ITANIUM-NOT: !{i64 {{.*}}, [3 x i8*]* @_ZTVN12_GLOBAL__N_11BE,
+// MS-NOT: !{i64 {{.*}}, [2 x i8*]* @[[B_VTABLE]],