implement raw fat pointer ops

Author: Ariel Ben-Yehuda

src/librustc_trans/trans/expr.rs

@@ -1682,20 +1682,70 @@ fn trans_addr_of<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
     }
 }
 
-// Important to get types for both lhs and rhs, because one might be _|_
-// and the other not.
-fn trans_eager_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
-                                 binop_expr: &hir::Expr,
-                                 binop_ty: Ty<'tcx>,
-                                 op: hir::BinOp,
-                                 lhs_t: Ty<'tcx>,
-                                 lhs: ValueRef,
-                                 rhs_t: Ty<'tcx>,
-                                 rhs: ValueRef)
-                                 -> DatumBlock<'blk, 'tcx, Expr> {
-    let _icx = push_ctxt("trans_eager_binop");
+fn trans_fat_ptr_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
+                                   binop_expr: &hir::Expr,
+                                   binop_ty: Ty<'tcx>,
+                                   op: hir::BinOp,
+                                   lhs: Datum<'tcx, Rvalue>,
+                                   rhs: Datum<'tcx, Rvalue>)
+                                   -> DatumBlock<'blk, 'tcx, Expr>
+{
+    let debug_loc = binop_expr.debug_loc();
+
+    let lhs_addr = Load(bcx, GEPi(bcx, lhs.val, &[0, abi::FAT_PTR_ADDR]));
+    let lhs_extra = Load(bcx, GEPi(bcx, lhs.val, &[0, abi::FAT_PTR_EXTRA]));
+
+    let rhs_addr = Load(bcx, GEPi(bcx, rhs.val, &[0, abi::FAT_PTR_ADDR]));
+    let rhs_extra = Load(bcx, GEPi(bcx, rhs.val, &[0, abi::FAT_PTR_EXTRA]));
+
+    let val = match op.node {
+        hir::BiEq => {
+            let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
+            let extra_eq = ICmp(bcx, llvm::IntEQ, lhs_extra, rhs_extra, debug_loc);
+            And(bcx, addr_eq, extra_eq, debug_loc)
+        }
+        hir::BiNe => {
+            let addr_eq = ICmp(bcx, llvm::IntNE, lhs_addr, rhs_addr, debug_loc);
+            let extra_eq = ICmp(bcx, llvm::IntNE, lhs_extra, rhs_extra, debug_loc);
+            Or(bcx, addr_eq, extra_eq, debug_loc)
+        }
+        hir::BiLe | hir::BiLt | hir::BiGe | hir::BiGt => {
+            // a OP b ~ a.0 STRICT(OP) b.0 | (a.0 == b.0 && a.1 OP a.1)
+            let (op, strict_op) = match op.node {
+                hir::BiLt => (llvm::IntULT, llvm::IntULT),
+                hir::BiLe => (llvm::IntULE, llvm::IntULT),
+                hir::BiGt => (llvm::IntUGT, llvm::IntUGT),
+                hir::BiGe => (llvm::IntUGE, llvm::IntUGT),
+                _ => unreachable!()
+            };
+
+            let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
+            let extra_op = ICmp(bcx, op, lhs_extra, rhs_extra, debug_loc);
+            let addr_eq_extra_op = And(bcx, addr_eq, extra_op, debug_loc);
+
+            let addr_strict = ICmp(bcx, strict_op, lhs_addr, rhs_addr, debug_loc);
+            Or(bcx, addr_strict, addr_eq_extra_op, debug_loc)
+        }
+        _ => {
+            bcx.tcx().sess.span_bug(binop_expr.span, "unexpected binop");
+        }
+    };
+
+    immediate_rvalue_bcx(bcx, val, binop_ty).to_expr_datumblock()
+}
+
+fn trans_scalar_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
+                                  binop_expr: &hir::Expr,
+                                  binop_ty: Ty<'tcx>,
+                                  op: hir::BinOp,
+                                  lhs: Datum<'tcx, Rvalue>,
+                                  rhs: Datum<'tcx, Rvalue>)
+                                  -> DatumBlock<'blk, 'tcx, Expr>
+{
+    let _icx = push_ctxt("trans_scalar_binop");
 
     let tcx = bcx.tcx();
+    let lhs_t = lhs.ty;
     assert!(!lhs_t.is_simd());
     let is_float = lhs_t.is_fp();
     let is_signed = lhs_t.is_signed();
@@ -1704,6 +1754,8 @@ fn trans_eager_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
     let binop_debug_loc = binop_expr.debug_loc();
 
     let mut bcx = bcx;
+    let lhs = lhs.to_llscalarish(bcx);
+    let rhs = rhs.to_llscalarish(bcx);
     let val = match op.node {
       hir::BiAdd => {
         if is_float {
@@ -1745,7 +1797,7 @@ fn trans_eager_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
                                                   op,
                                                   lhs,
                                                   rhs,
-                                                  rhs_t);
+                                                  lhs_t);
             if is_signed {
                 SDiv(bcx, lhs, rhs, binop_debug_loc)
             } else {
@@ -1796,7 +1848,7 @@ fn trans_eager_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
             // Only zero-check integers; fp %0 is NaN
             bcx = base::fail_if_zero_or_overflows(bcx,
                                                   expr_info(binop_expr),
-                                                  op, lhs, rhs, rhs_t);
+                                                  op, lhs, rhs, lhs_t);
             if is_signed {
                 SRem(bcx, lhs, rhs, binop_debug_loc)
             } else {
@@ -1896,23 +1948,26 @@ fn trans_binary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
         }
         _ => {
             let mut bcx = bcx;
-            let lhs_datum = unpack_datum!(bcx, trans(bcx, lhs));
-            let rhs_datum = unpack_datum!(bcx, trans(bcx, rhs));
             let binop_ty = expr_ty(bcx, expr);
 
-            debug!("trans_binary (expr {}): lhs_datum={}",
-                   expr.id,
-                   lhs_datum.to_string(ccx));
-            let lhs_ty = lhs_datum.ty;
-            let lhs = lhs_datum.to_llscalarish(bcx);
-
-            debug!("trans_binary (expr {}): rhs_datum={}",
-                   expr.id,
-                   rhs_datum.to_string(ccx));
-            let rhs_ty = rhs_datum.ty;
-            let rhs = rhs_datum.to_llscalarish(bcx);
-            trans_eager_binop(bcx, expr, binop_ty, op,
-                              lhs_ty, lhs, rhs_ty, rhs)
+            let lhs = unpack_datum!(bcx, trans(bcx, lhs));
+            let lhs = unpack_datum!(bcx, lhs.to_rvalue_datum(bcx, "binop_lhs"));
+            debug!("trans_binary (expr {}): lhs={}",
+                   expr.id, lhs.to_string(ccx));
+            let rhs = unpack_datum!(bcx, trans(bcx, rhs));
+            let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "binop_rhs"));
+            debug!("trans_binary (expr {}): rhs={}",
+                   expr.id, rhs.to_string(ccx));
+
+            if type_is_fat_ptr(ccx.tcx(), lhs.ty) {
+                assert!(type_is_fat_ptr(ccx.tcx(), rhs.ty),
+                        "built-in binary operators on fat pointers are homogeneous");
+                trans_fat_ptr_binop(bcx, expr, binop_ty, op, lhs, rhs)
+            } else {
+                assert!(!type_is_fat_ptr(ccx.tcx(), rhs.ty),
+                        "built-in binary operators on fat pointers are homogeneous");
+                trans_scalar_binop(bcx, expr, binop_ty, op, lhs, rhs)
+            }
         }
     }
 }
@@ -2123,21 +2178,19 @@ fn trans_assign_op<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
     assert!(!bcx.tcx().is_method_call(expr.id));
 
     // Evaluate LHS (destination), which should be an lvalue
-    let dst_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign_op"));
-    assert!(!bcx.fcx.type_needs_drop(dst_datum.ty));
-    let dst_ty = dst_datum.ty;
-    let dst = load_ty(bcx, dst_datum.val, dst_datum.ty);
+    let dst = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign_op"));
+    assert!(!bcx.fcx.type_needs_drop(dst.ty));
+    let lhs = load_ty(bcx, dst.val, dst.ty);
+    let lhs = immediate_rvalue(lhs, dst.ty);
 
-    // Evaluate RHS
-    let rhs_datum = unpack_datum!(bcx, trans(bcx, &*src));
-    let rhs_ty = rhs_datum.ty;
-    let rhs = rhs_datum.to_llscalarish(bcx);
+    // Evaluate RHS - FIXME(#28160) this sucks
+    let rhs = unpack_datum!(bcx, trans(bcx, &*src));
+    let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "assign_op_rhs"));
 
     // Perform computation and store the result
     let result_datum = unpack_datum!(
-        bcx, trans_eager_binop(bcx, expr, dst_datum.ty, op,
-                               dst_ty, dst, rhs_ty, rhs));
-    return result_datum.store_to(bcx, dst_datum.val);
+        bcx, trans_scalar_binop(bcx, expr, dst.ty, op, lhs, rhs));
+    return result_datum.store_to(bcx, dst.val);
 }
 
 fn auto_ref<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,

src/test/run-pass/issue-27054-primitive-binary-ops.rs

@@ -0,0 +1,14 @@
+// Copyright 2015 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.
+
+fn main() {
+    let x = &mut 1;
+    assert_eq!(*x + { *x=2; 1 }, 2);
+}

src/test/run-pass/raw-fat-ptr.rs

@@ -0,0 +1,127 @@
+// Copyright 2015 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.
+
+// check raw fat pointer ops
+
+use std::mem;
+
+fn assert_inorder<T: PartialEq + PartialOrd>(a: &[T]) {
+    for i in 0..a.len() {
+        for j in 0..a.len() {
+            if i < j {
+                assert!(a[i] < a[j]);
+                assert!(a[i] <= a[j]);
+                assert!(!(a[i] == a[j]));
+                assert!(a[i] != a[j]);
+                assert!(!(a[i] >= a[j]));
+                assert!(!(a[i] > a[j]));
+            } else if i == j {
+                assert!(!(a[i] < a[j]));
+                assert!(a[i] <= a[j]);
+                assert!(a[i] == a[j]);
+                assert!(!(a[i] != a[j]));
+                assert!(a[i] >= a[j]);
+                assert!(!(a[i] > a[j]));
+            } else {
+                assert!(!(a[i] < a[j]));
+                assert!(!(a[i] <= a[j]));
+                assert!(!(a[i] == a[j]));
+                assert!(a[i] != a[j]);
+                assert!(a[i] >= a[j]);
+                assert!(a[i] > a[j]);
+            }
+        }
+    }
+}
+
+trait Foo { fn foo(&self) -> usize; }
+impl<T> Foo for T {
+    fn foo(&self) -> usize {
+        mem::size_of::<T>()
+    }
+}
+
+struct S<T:?Sized>(u32, T);
+
+fn main() {
+    let mut array = [0,1,2,3,4];
+    let mut array2 = [5,6,7,8,9];
+
+    // fat ptr comparison: addr then extra
+
+    // check ordering for arrays
+    let mut ptrs: Vec<*const [u8]> = vec![
+        &array[0..0], &array[0..1], &array, &array[1..]
+    ];
+
+    let array_addr = &array as *const [u8] as *const u8 as usize;
+    let array2_addr = &array2 as *const [u8] as *const u8 as usize;
+    if array2_addr < array_addr {
+        ptrs.insert(0, &array2);
+    } else {
+        ptrs.push(&array2);
+    }
+    assert_inorder(&ptrs);
+
+    // check ordering for mut arrays
+    let mut ptrs: Vec<*mut [u8]> = vec![
+        &mut array[0..0], &mut array[0..1], &mut array, &mut array[1..]
+    ];
+
+    let array_addr = &mut array as *mut [u8] as *mut u8 as usize;
+    let array2_addr = &mut array2 as *mut [u8] as *mut u8 as usize;
+    if array2_addr < array_addr {
+        ptrs.insert(0, &mut array2);
+    } else {
+        ptrs.push(&mut array2);
+    }
+    assert_inorder(&ptrs);
+
+    let mut u8_ = (0u8, 1u8);
+    let mut u32_ = (4u32, 5u32);
+
+    // check ordering for ptrs
+    let buf: &mut [*const Foo] = &mut [
+        &u8_, &u8_.0,
+        &u32_, &u32_.0,
+    ];
+    buf.sort_by(|u,v| {
+        let u : [*const (); 2] = unsafe { mem::transmute(*u) };
+        let v : [*const (); 2] = unsafe { mem::transmute(*v) };
+        u.cmp(&v)
+    });
+    assert_inorder(buf);
+
+    // check ordering for mut ptrs
+    let buf: &mut [*mut Foo] = &mut [
+        &mut u8_, &mut u8_.0,
+        &mut u32_, &mut u32_.0,
+    ];
+    buf.sort_by(|u,v| {
+        let u : [*const (); 2] = unsafe { mem::transmute(*u) };
+        let v : [*const (); 2] = unsafe { mem::transmute(*v) };
+        u.cmp(&v)
+    });
+    assert_inorder(buf);
+
+    // check ordering for structs containing arrays
+    let ss: (S<[u8; 2]>,
+             S<[u8; 3]>,
+             S<[u8; 2]>) = (
+        S(7, [8, 9]),
+        S(10, [11, 12, 13]),
+        S(4, [5, 6])
+    );
+    assert_inorder(&[
+        &ss.0 as *const S<[u8]>,
+        &ss.1 as *const S<[u8]>,
+        &ss.2 as *const S<[u8]>
+    ]);
+}