Implement the #[sanitize(..)] attribute

This change implements the #[sanitize(..)] attribute, which opts to
replace the currently unstable #[no_sanitize]. Essentially the new
attribute works similar as #[no_sanitize], just with more flexible
options regarding where it is applied. E.g. it is possible to turn
a certain sanitizer either on or off:
`#[sanitize(address = "on|off")]`

This attribute now also applies to more places, e.g. it is possible
to turn off a sanitizer for an entire module or impl block:
```rust
\#[sanitize(address = "off")]
mod foo {
    fn unsanitized(..) {}

    #[sanitize(address = "on")]
    fn sanitized(..) {}
}

\#[sanitize(thread = "off")]
impl MyTrait for () {
    ...
}
```

This attribute is enabled behind the unstable `sanitize` feature.

1 files changed, 118 insertions, 0 deletions

diff --git a/tests/codegen-llvm/sanitizer/sanitize-off.rs b/tests/codegen-llvm/sanitizer/sanitize-off.rs
new file mode 100644
index 00000000000..0b0c01ed962
--- /dev/null
+++ b/tests/codegen-llvm/sanitizer/sanitize-off.rs
@@ -0,0 +1,118 @@
+// Verifies that the `#[sanitize(address = "off")]` attribute can be used to
+// selectively disable sanitizer instrumentation.
+//
+//@ needs-sanitizer-address
+//@ compile-flags: -Zsanitizer=address -Ctarget-feature=-crt-static -Copt-level=0
+
+#![crate_type = "lib"]
+#![feature(sanitize)]
+
+// CHECK:     @UNSANITIZED = constant{{.*}} no_sanitize_address
+// CHECK-NOT: @__asan_global_SANITIZED
+#[no_mangle]
+#[sanitize(address = "off")]
+pub static UNSANITIZED: u32 = 0;
+
+// CHECK: @__asan_global_SANITIZED
+#[no_mangle]
+pub static SANITIZED: u32 = 0;
+
+// CHECK-LABEL: ; sanitize_off::unsanitized
+// CHECK-NEXT:  ; Function Attrs:
+// CHECK-NOT:   sanitize_address
+// CHECK:       start:
+// CHECK-NOT:   call void @__asan_report_load
+// CHECK:       }
+#[sanitize(address = "off")]
+pub fn unsanitized(b: &mut u8) -> u8 {
+    *b
+}
+
+// CHECK-LABEL: ; sanitize_off::sanitized
+// CHECK-NEXT:  ; Function Attrs:
+// CHECK:       sanitize_address
+// CHECK:       start:
+// CHECK:       call void @__asan_report_load
+// CHECK:       }
+pub fn sanitized(b: &mut u8) -> u8 {
+    *b
+}
+
+#[sanitize(address = "off")]
+pub mod foo {
+    // CHECK-LABEL: ; sanitize_off::foo::unsanitized
+    // CHECK-NEXT:  ; Function Attrs:
+    // CHECK-NOT:   sanitize_address
+    // CHECK:       start:
+    // CHECK-NOT:   call void @__asan_report_load
+    // CHECK:       }
+    pub fn unsanitized(b: &mut u8) -> u8 {
+        *b
+    }
+
+    // CHECK-LABEL: ; sanitize_off::foo::sanitized
+    // CHECK-NEXT:  ; Function Attrs:
+    // CHECK:       sanitize_address
+    // CHECK:       start:
+    // CHECK:       call void @__asan_report_load
+    // CHECK:       }
+    #[sanitize(address = "on")]
+    pub fn sanitized(b: &mut u8) -> u8 {
+        *b
+    }
+}
+
+pub trait MyTrait {
+    fn unsanitized(&self, b: &mut u8) -> u8;
+    fn sanitized(&self, b: &mut u8) -> u8;
+
+    // CHECK-LABEL: ; sanitize_off::MyTrait::unsanitized_default
+    // CHECK-NEXT:  ; Function Attrs:
+    // CHECK-NOT:   sanitize_address
+    // CHECK:       start:
+    // CHECK-NOT:   call void @__asan_report_load
+    // CHECK:       }
+    #[sanitize(address = "off")]
+    fn unsanitized_default(&self, b: &mut u8) -> u8 {
+        *b
+    }
+
+    // CHECK-LABEL: ; sanitize_off::MyTrait::sanitized_default
+    // CHECK-NEXT:  ; Function Attrs:
+    // CHECK:       sanitize_address
+    // CHECK:       start:
+    // CHECK:       call void @__asan_report_load
+    // CHECK:       }
+    fn sanitized_default(&self, b: &mut u8) -> u8 {
+        *b
+    }
+}
+
+#[sanitize(address = "off")]
+impl MyTrait for () {
+    // CHECK-LABEL: ; <() as sanitize_off::MyTrait>::unsanitized
+    // CHECK-NEXT:  ; Function Attrs:
+    // CHECK-NOT:   sanitize_address
+    // CHECK:       start:
+    // CHECK-NOT:   call void @__asan_report_load
+    // CHECK:       }
+    fn unsanitized(&self, b: &mut u8) -> u8 {
+        *b
+    }
+
+    // CHECK-LABEL: ; <() as sanitize_off::MyTrait>::sanitized
+    // CHECK-NEXT:  ; Function Attrs:
+    // CHECK:       sanitize_address
+    // CHECK:       start:
+    // CHECK:       call void @__asan_report_load
+    // CHECK:       }
+    #[sanitize(address = "on")]
+    fn sanitized(&self, b: &mut u8) -> u8 {
+        *b
+    }
+}
+
+pub fn expose_trait(b: &mut u8) -> u8 {
+    <() as MyTrait>::unsanitized_default(&(), b);
+    <() as MyTrait>::sanitized_default(&(), b)
+}