Rename SimpleJIT to JIT as it isn't simple anymore

cranelift/jit/src/compiled_blob.rs

@@ -0,0 +1,79 @@
+use cranelift_codegen::binemit::Reloc;
+use cranelift_codegen::ir::ExternalName;
+use cranelift_module::RelocRecord;
+use std::convert::TryFrom;
+
+#[derive(Clone)]
+pub(crate) struct CompiledBlob {
+    pub(crate) ptr: *mut u8,
+    pub(crate) size: usize,
+    pub(crate) relocs: Vec<RelocRecord>,
+}
+
+impl CompiledBlob {
+    pub(crate) fn perform_relocations(
+        &self,
+        get_address: impl Fn(&ExternalName) -> *const u8,
+        get_got_entry: impl Fn(&ExternalName) -> *const u8,
+        get_plt_entry: impl Fn(&ExternalName) -> *const u8,
+    ) {
+        use std::ptr::write_unaligned;
+
+        for &RelocRecord {
+            reloc,
+            offset,
+            ref name,
+            addend,
+        } in &self.relocs
+        {
+            debug_assert!((offset as usize) < self.size);
+            let at = unsafe { self.ptr.offset(isize::try_from(offset).unwrap()) };
+            match reloc {
+                Reloc::Abs4 => {
+                    let base = get_address(name);
+                    let what = unsafe { base.offset(isize::try_from(addend).unwrap()) };
+                    #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+                    unsafe {
+                        write_unaligned(at as *mut u32, u32::try_from(what as usize).unwrap())
+                    };
+                }
+                Reloc::Abs8 => {
+                    let base = get_address(name);
+                    let what = unsafe { base.offset(isize::try_from(addend).unwrap()) };
+                    #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+                    unsafe {
+                        write_unaligned(at as *mut u64, u64::try_from(what as usize).unwrap())
+                    };
+                }
+                Reloc::X86PCRel4 | Reloc::X86CallPCRel4 => {
+                    let base = get_address(name);
+                    let what = unsafe { base.offset(isize::try_from(addend).unwrap()) };
+                    let pcrel = i32::try_from((what as isize) - (at as isize)).unwrap();
+                    #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+                    unsafe {
+                        write_unaligned(at as *mut i32, pcrel)
+                    };
+                }
+                Reloc::X86GOTPCRel4 => {
+                    let base = get_got_entry(name);
+                    let what = unsafe { base.offset(isize::try_from(addend).unwrap()) };
+                    let pcrel = i32::try_from((what as isize) - (at as isize)).unwrap();
+                    #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+                    unsafe {
+                        write_unaligned(at as *mut i32, pcrel)
+                    };
+                }
+                Reloc::X86CallPLTRel4 => {
+                    let base = get_plt_entry(name);
+                    let what = unsafe { base.offset(isize::try_from(addend).unwrap()) };
+                    let pcrel = i32::try_from((what as isize) - (at as isize)).unwrap();
+                    #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+                    unsafe {
+                        write_unaligned(at as *mut i32, pcrel)
+                    };
+                }
+                _ => unimplemented!(),
+            }
+        }
+    }
+}