Auto merge of #18668 - bholley:mprotect_diagnostics, r=Manishearth

Add mprotect diagnostics for HashMap crash

https://bugzilla.mozilla.org/show_bug.cgi?id=1403397

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ports/geckolib/Cargo.toml

@@ -17,6 +17,7 @@ gecko_debug = ["style/gecko_debug"]
 atomic_refcell = "0.1"
 cssparser = "0.21.1"
 env_logger = {version = "0.4", default-features = false} # disable `regex` to reduce code size
+hashglobe = {path = "../../components/hashglobe"}
 libc = "0.2"
 log = {version = "0.3.5", features = ["release_max_level_info"]}
 malloc_size_of = {path = "../../components/malloc_size_of"}

ports/geckolib/glue.rs

@@ -181,6 +181,10 @@ pub extern "C" fn Servo_Initialize(dummy_url_data: *mut URLExtraData) {
 
     // Initialize the dummy url data
     unsafe { DUMMY_URL_DATA = dummy_url_data; }
+
+    // Set the system page size.
+    let page_size = unsafe { bindings::Gecko_GetSystemPageSize() };
+    ::hashglobe::SYSTEM_PAGE_SIZE.store(page_size, ::std::sync::atomic::Ordering::Relaxed);
 }
 
 #[no_mangle]
@@ -4052,3 +4056,9 @@ pub extern "C" fn Servo_HasPendingRestyleAncestor(element: RawGeckoElementBorrow
     }
     false
 }
+
+#[no_mangle]
+pub extern "C" fn Servo_CorruptRuleHashAndCrash(set: RawServoStyleSetBorrowed, index: usize) {
+    let per_doc_data = PerDocumentStyleData::from_ffi(set).borrow();
+    per_doc_data.stylist.corrupt_rule_hash_and_crash(index);
+}

ports/geckolib/lib.rs

@@ -6,6 +6,7 @@
 
 extern crate cssparser;
 extern crate env_logger;
+extern crate hashglobe;
 extern crate libc;
 #[macro_use] extern crate log;
 extern crate malloc_size_of;