Add clif-backend crate and runtime example

lib/runtime/src/instance.rs

@@ -102,14 +102,12 @@ impl Instance {
             .chain(iter::once(libffi_arg(&vmctx_ptr)))
             .collect();
 
-        let func_ptr = CodePtr::from_ptr(
-            self.module
+        let func_ptr = CodePtr::from_ptr(self.module
                 .func_resolver
                 .get(&self.module, func_index)
                 .expect("broken invariant, func resolver not synced with module.exports")
                 .cast()
-                .as_ptr(),
-        );
+                .as_ptr());
 
         call_protected(|| {
             self.module.sig_registry.lookup_func_sig(sig_index)

lib/runtime/src/lib.rs

@@ -4,19 +4,19 @@ mod backend;
 mod backing;
 mod instance;
 mod memory;
-mod module;
 mod sig_registry;
 mod table;
 mod recovery;
 mod sighandler;
-mod mmap;
+pub mod mmap;
+pub mod module;
 pub mod types;
 pub mod vm;
 pub mod vmcalls;
 
 pub use self::backend::{Compiler, FuncResolver};
 pub use self::instance::{Import, ImportResolver, Imports, Instance};
-pub use self::module::Module;
+pub use self::module::{Module, ModuleInner};
 pub use self::sig_registry::SigRegistry;
 pub use self::memory::LinearMemory;
 

lib/runtime/src/mmap.rs

@@ -45,7 +45,8 @@ impl Mmap {
     pub unsafe fn protect(&mut self, range: Range<usize>, protect: Protect) -> Result<(), String> {
         let page_size = page_size::get();
         let start = self.ptr.add(round_down_to_page_size(range.start, page_size));
-        let size = range.end - range.start;
+        let size = round_up_to_page_size(range.end - range.start, page_size);
+        assert!(size <= self.size);
 
         let success = libc::mprotect(start as _, size, protect as i32);
         if success == -1 {
@@ -67,7 +68,7 @@ impl Mmap {
         slice::from_raw_parts_mut(self.ptr, self.size)
     }
 
-    pub fn as_ptr(&mut self) -> *mut u8 {
+    pub fn as_ptr(&self) -> *mut u8 {
         self.ptr
     }
 }