Great separation of librustc_codegen_llvm: librustc_codegen_ssa compiles

1 files changed, 126 insertions, 0 deletions

diff --git a/src/librustc_codegen_ssa/meth.rs b/src/librustc_codegen_ssa/meth.rs
new file mode 100644
index 00000000000..4584adfff65
--- /dev/null
+++ b/src/librustc_codegen_ssa/meth.rs
@@ -0,0 +1,126 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use rustc_target::abi::call::FnType;
+use callee;
+use rustc_mir::monomorphize;
+
+use interfaces::*;
+
+use rustc::ty::{self, Ty};
+
+#[derive(Copy, Clone, Debug)]
+pub struct VirtualIndex(u64);
+
+pub const DESTRUCTOR: VirtualIndex = VirtualIndex(0);
+pub const SIZE: VirtualIndex = VirtualIndex(1);
+pub const ALIGN: VirtualIndex = VirtualIndex(2);
+
+impl<'a, 'tcx: 'a> VirtualIndex {
+    pub fn from_index(index: usize) -> Self {
+        VirtualIndex(index as u64 + 3)
+    }
+
+    pub fn get_fn<Bx: BuilderMethods<'a, 'tcx>>(
+        self,
+        bx: &Bx,
+        llvtable: Bx::Value,
+        fn_ty: &FnType<'tcx, Ty<'tcx>>
+    ) -> Bx::Value {
+        // Load the data pointer from the object.
+        debug!("get_fn({:?}, {:?})", llvtable, self);
+
+        let llvtable = bx.pointercast(
+            llvtable,
+            bx.cx().type_ptr_to(bx.cx().fn_ptr_backend_type(fn_ty))
+        );
+        let ptr_align = bx.tcx().data_layout.pointer_align;
+        let ptr = bx.load(
+            bx.inbounds_gep(llvtable, &[bx.cx().const_usize(self.0)]),
+            ptr_align
+        );
+        bx.nonnull_metadata(ptr);
+        // Vtable loads are invariant
+        bx.set_invariant_load(ptr);
+        ptr
+    }
+
+    pub fn get_usize<Bx: BuilderMethods<'a, 'tcx>>(
+        self,
+        bx: &Bx,
+        llvtable: Bx::Value
+    ) -> Bx::Value {
+        // Load the data pointer from the object.
+        debug!("get_int({:?}, {:?})", llvtable, self);
+
+        let llvtable = bx.pointercast(llvtable, bx.cx().type_ptr_to(bx.cx().type_isize()));
+        let usize_align = bx.tcx().data_layout.pointer_align;
+        let ptr = bx.load(
+            bx.inbounds_gep(llvtable, &[bx.cx().const_usize(self.0)]),
+            usize_align
+        );
+        // Vtable loads are invariant
+        bx.set_invariant_load(ptr);
+        ptr
+    }
+}
+
+/// Creates a dynamic vtable for the given type and vtable origin.
+/// This is used only for objects.
+///
+/// The vtables are cached instead of created on every call.
+///
+/// The `trait_ref` encodes the erased self type. Hence if we are
+/// making an object `Foo<Trait>` from a value of type `Foo<T>`, then
+/// `trait_ref` would map `T:Trait`.
+pub fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
+    cx: &Cx,
+    ty: Ty<'tcx>,
+    trait_ref: ty::PolyExistentialTraitRef<'tcx>,
+) -> Cx::Value {
+    let tcx = cx.tcx();
+
+    debug!("get_vtable(ty={:?}, trait_ref={:?})", ty, trait_ref);
+
+    // Check the cache.
+    if let Some(&val) = cx.vtables().borrow().get(&(ty, trait_ref)) {
+        return val;
+    }
+
+    // Not in the cache. Build it.
+    let nullptr = cx.const_null(cx.type_i8p());
+
+    let methods = tcx.vtable_methods(trait_ref.with_self_ty(tcx, ty));
+    let methods = methods.iter().cloned().map(|opt_mth| {
+        opt_mth.map_or(nullptr, |(def_id, substs)| {
+            callee::resolve_and_get_fn_for_vtable(cx, def_id, substs)
+        })
+    });
+
+    let (size, align) = cx.layout_of(ty).size_and_align();
+    // /////////////////////////////////////////////////////////////////////////////////////////////
+    // If you touch this code, be sure to also make the corresponding changes to
+    // `get_vtable` in rust_mir/interpret/traits.rs
+    // /////////////////////////////////////////////////////////////////////////////////////////////
+    let components: Vec<_> = [
+        cx.get_fn(monomorphize::resolve_drop_in_place(cx.tcx(), ty)),
+        cx.const_usize(size.bytes()),
+        cx.const_usize(align.abi())
+    ].iter().cloned().chain(methods).collect();
+
+    let vtable_const = cx.const_struct(&components, false);
+    let align = cx.data_layout().pointer_align;
+    let vtable = cx.static_addr_of(vtable_const, align, Some("vtable"));
+
+    cx.create_vtable_metadata(ty, vtable);
+
+    cx.vtables().borrow_mut().insert((ty, trait_ref), vtable);
+    vtable
+}