add ABIInfo trait and separate x86-64 ABI implementation from foreign trans

ABIInfo provides a method to translate the type of foreign function.
The foreign trans uses the method to get ABI-specific type and
uses the result to generate LLVM instructions for wrapper and shim functions.

Author: crabtw

src/librustc/middle/trans/cabi.rs

@@ -0,0 +1,214 @@
+// 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 lib::llvm::{llvm, TypeRef, ValueRef, Attribute};
+use middle::trans::base::*;
+use middle::trans::build::*;
+use middle::trans::common::*;
+
+export ABIInfo, LLVMType, FnType;
+export llvm_abi_info;
+
+trait ABIInfo {
+    fn compute_info(&self,
+                    atys: &[TypeRef],
+                    rty: TypeRef,
+                    ret_def: bool) -> FnType;
+}
+
+struct LLVMType {
+    cast: bool,
+    ty: TypeRef
+}
+
+struct FnType {
+    arg_tys: ~[LLVMType],
+    ret_ty: LLVMType,
+    attrs: ~[Option<Attribute>],
+    sret: bool
+}
+
+impl FnType {
+    fn decl_fn(&self, decl: fn(fnty: TypeRef) -> ValueRef) -> ValueRef {
+        let atys = vec::map(self.arg_tys, |t| t.ty);
+        let rty = self.ret_ty.ty;
+        let fnty = T_fn(atys, rty);
+        let llfn = decl(fnty);
+
+        for vec::eachi(self.attrs) |i, a| {
+            match *a {
+                option::Some(attr) => {
+                    unsafe {
+                        let llarg = get_param(llfn, i);
+                        llvm::LLVMAddAttribute(llarg, attr as c_uint);
+                    }
+                }
+                _ => ()
+            }
+        }
+        return llfn;
+    }
+
+    fn build_shim_args(&self, bcx: block,
+                       arg_tys: &[TypeRef],
+                       llargbundle: ValueRef) -> ~[ValueRef] {
+        let mut atys = /*bad*/copy self.arg_tys;
+        let mut attrs = /*bad*/copy self.attrs;
+
+        let mut llargvals = ~[];
+        let mut i = 0u;
+        let n = vec::len(arg_tys);
+
+        if self.sret {
+            let llretptr = GEPi(bcx, llargbundle, [0u, n]);
+            let llretloc = Load(bcx, llretptr);
+                llargvals = ~[llretloc];
+                atys = vec::tail(atys);
+                attrs = vec::tail(attrs);
+        }
+
+        while i < n {
+            let llargval = if atys[i].cast {
+                let arg_ptr = GEPi(bcx, llargbundle, [0u, i]);
+                let arg_ptr = BitCast(bcx, arg_ptr, T_ptr(atys[i].ty));
+                Load(bcx, arg_ptr)
+            } else if attrs[i].is_some() {
+                GEPi(bcx, llargbundle, [0u, i])
+            } else {
+                load_inbounds(bcx, llargbundle, [0u, i])
+            };
+            llargvals.push(llargval);
+            i += 1u;
+        }
+
+        return llargvals;
+    }
+
+    fn build_shim_ret(&self, bcx: block,
+                      arg_tys: &[TypeRef], ret_def: bool,
+                      llargbundle: ValueRef, llretval: ValueRef) {
+        for vec::eachi(self.attrs) |i, a| {
+            match *a {
+                Some(attr) => {
+                    unsafe {
+                        llvm::LLVMAddInstrAttribute(
+                            llretval, (i + 1u) as c_uint,
+                                        attr as c_uint);
+                    }
+                }
+                _ => ()
+            }
+        }
+        if self.sret || !ret_def {
+            return;
+        }
+        let n = vec::len(arg_tys);
+        // R** llretptr = &args->r;
+        let llretptr = GEPi(bcx, llargbundle, [0u, n]);
+        // R* llretloc = *llretptr; /* (args->r) */
+        let llretloc = Load(bcx, llretptr);
+        if self.ret_ty.cast {
+            let tmp_ptr = BitCast(bcx, llretloc, T_ptr(self.ret_ty.ty));
+            // *args->r = r;
+            Store(bcx, llretval, tmp_ptr);
+        } else {
+            // *args->r = r;
+            Store(bcx, llretval, llretloc);
+        };
+    }
+
+    fn build_wrap_args(&self, bcx: block, ret_ty: TypeRef,
+                       llwrapfn: ValueRef, llargbundle: ValueRef) {
+        let mut atys = /*bad*/copy self.arg_tys;
+        let mut attrs = /*bad*/copy self.attrs;
+        let mut j = 0u;
+        let llretptr = if self.sret {
+            atys = vec::tail(atys);
+            attrs = vec::tail(attrs);
+            j = 1u;
+            get_param(llwrapfn, 0u)
+        } else if self.ret_ty.cast {
+            let retptr = alloca(bcx, self.ret_ty.ty);
+            BitCast(bcx, retptr, T_ptr(ret_ty))
+        } else {
+            alloca(bcx, ret_ty)
+        };
+
+        let mut i = 0u;
+        let n = vec::len(atys);
+        while i < n {
+            let mut argval = get_param(llwrapfn, i + j);
+            if attrs[i].is_some() {
+                argval = Load(bcx, argval);
+                store_inbounds(bcx, argval, llargbundle, [0u, i]);
+            } else if atys[i].cast {
+                let argptr = GEPi(bcx, llargbundle, [0u, i]);
+                let argptr = BitCast(bcx, argptr, T_ptr(atys[i].ty));
+                Store(bcx, argval, argptr);
+            } else {
+                store_inbounds(bcx, argval, llargbundle, [0u, i]);
+            }
+            i += 1u;
+        }
+        store_inbounds(bcx, llretptr, llargbundle, [0u, n]);
+    }
+
+    fn build_wrap_ret(&self, bcx: block,
+                      arg_tys: &[TypeRef], ret_def: bool,
+                      llargbundle: ValueRef) {
+        if self.sret || !ret_def {
+            RetVoid(bcx);
+            return;
+        }
+        let n = vec::len(arg_tys);
+        let llretval = load_inbounds(bcx, llargbundle, ~[0u, n]);
+        let llretval = if self.ret_ty.cast {
+            let retptr = BitCast(bcx, llretval, T_ptr(self.ret_ty.ty));
+            Load(bcx, retptr)
+        } else {
+            Load(bcx, llretval)
+        };
+        Ret(bcx, llretval);
+    }
+}
+
+enum LLVM_ABIInfo { LLVM_ABIInfo }
+
+impl LLVM_ABIInfo: ABIInfo {
+    fn compute_info(&self,
+                    atys: &[TypeRef],
+                    rty: TypeRef,
+                    _ret_def: bool) -> FnType {
+        let arg_tys = do atys.map |a| {
+            LLVMType { cast: false, ty: *a }
+        };
+        let ret_ty = LLVMType {
+            cast: false,
+            ty: rty
+        };
+        let attrs = do atys.map |_| {
+            option::None
+        };
+        let sret = false;
+
+        return FnType {
+            arg_tys: arg_tys,
+            ret_ty: ret_ty,
+            attrs: attrs,
+            sret: sret
+        };
+    }
+}
+
+fn llvm_abi_info() -> ABIInfo {
+    return LLVM_ABIInfo as ABIInfo;
+}
+
+