[PATCH] D51418: [AArch64] Enable return address signing for static ctors

[Oliver Stannard via Phabricator via llvm-commits]

olista01 created this revision.
olista01 added a reviewer: LukeCheeseman.
Herald added a reviewer: javed.absar.
Herald added a subscriber: kristof.beyls.

Functions generated by clang and included in the .init_array section (such as static constructors) do not follow the usual code path for adding target-specific function attributes, so we have to add the return address signing attribute here too, as is currently done for the sanitisers.


Repository:
  rL LLVM

https://reviews.llvm.org/D51418

Files:
  lib/CodeGen/CGDeclCXX.cpp
  test/CodeGenCXX/aarch64-sign-return-address-static-ctor.cpp


Index: test/CodeGenCXX/aarch64-sign-return-address-static-ctor.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/aarch64-sign-return-address-static-ctor.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang -target aarch64-arm-none-eabi -S -emit-llvm -o - -msign-return-address=none  %s | \
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NONE
+// RUN: %clang -target aarch64-arm-none-eabi -S -emit-llvm -o - -msign-return-address=non-leaf %s | \
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-PARTIAL
+// RUN: %clang -target aarch64-arm-none-eabi -S -emit-llvm -o - -msign-return-address=all %s | \
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-ALL
+
+struct Foo {
+  Foo() {}
+  ~Foo() {}
+};
+
+Foo f;
+
+// CHECK: @llvm.global_ctors {{.*}}i32 65535, void ()* @[[CTOR_FN:.*]], i8* null
+
+// CHECK: @[[CTOR_FN]]() #[[ATTR:[0-9]*]]
+
+// CHECK-NONE-NOT: attributes #[[ATTR]] = { {{.*}} "sign-return-address"={{.*}} }}
+// CHECK-PARTIAL: attributes #[[ATTR]] = { {{.*}} "sign-return-address"="non-leaf" {{.*}}}
+// CHECK-ALL: attributes #[[ATTR]] = { {{.*}} "sign-return-address"="all" {{.*}} }
Index: lib/CodeGen/CGDeclCXX.cpp
===================================================================
--- lib/CodeGen/CGDeclCXX.cpp
+++ lib/CodeGen/CGDeclCXX.cpp
@@ -355,6 +355,12 @@
       !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
     Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
 
+  auto RASignKind = getCodeGenOpts().getSignReturnAddress();
+  if (RASignKind != CodeGenOptions::SignReturnAddressScope::None)
+    Fn->addFnAttr("sign-return-address",
+                  RASignKind == CodeGenOptions::SignReturnAddressScope::All
+                      ? "all"
+                      : "non-leaf");
   return Fn;
 }
 


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