auto merge of #15464 : dotdash/rust/bool_stores, r=pcwalton

LLVM doesn't handle i1 value in allocas/memory very well and skips a number of optimizations if it hits it. So we have to do the same thing that Clang does, using i1 for SSA values, but storing i8 in memory.

Fixes #15203.

Author: bors

src/librustc/middle/trans/adt.rs

@@ -618,7 +618,7 @@ pub fn trans_case<'a>(bcx: &'a Block<'a>, r: &Repr, discr: Disr)
         RawNullablePointer { .. } |
         StructWrappedNullablePointer { .. } => {
             assert!(discr == 0 || discr == 1);
-            _match::single_result(Result::new(bcx, C_i1(bcx.ccx(), discr != 0)))
+            _match::single_result(Result::new(bcx, C_bool(bcx.ccx(), discr != 0)))
         }
     }
 }
@@ -641,7 +641,7 @@ pub fn trans_start_init(bcx: &Block, r: &Repr, val: ValueRef, discr: Disr) {
         }
         Univariant(ref st, true) => {
             assert_eq!(discr, 0);
-            Store(bcx, C_bool(bcx.ccx(), true),
+            Store(bcx, C_u8(bcx.ccx(), 1),
                   GEPi(bcx, val, [0, st.fields.len() - 1]))
         }
         Univariant(..) => {

src/librustc/middle/trans/base.rs

@@ -538,8 +538,8 @@ pub fn compare_scalar_values<'a>(
         // We don't need to do actual comparisons for nil.
         // () == () holds but () < () does not.
         match op {
-          ast::BiEq | ast::BiLe | ast::BiGe => return C_i1(cx.ccx(), true),
-          ast::BiNe | ast::BiLt | ast::BiGt => return C_i1(cx.ccx(), false),
+          ast::BiEq | ast::BiLe | ast::BiGe => return C_bool(cx.ccx(), true),
+          ast::BiNe | ast::BiLt | ast::BiGt => return C_bool(cx.ccx(), false),
           // refinements would be nice
           _ => die(cx)
         }
@@ -958,10 +958,42 @@ pub fn need_invoke(bcx: &Block) -> bool {
 
 pub fn load_if_immediate(cx: &Block, v: ValueRef, t: ty::t) -> ValueRef {
     let _icx = push_ctxt("load_if_immediate");
-    if type_is_immediate(cx.ccx(), t) { return Load(cx, v); }
+    if type_is_immediate(cx.ccx(), t) { return load_ty(cx, v, t); }
     return v;
 }
 
+pub fn load_ty(cx: &Block, ptr: ValueRef, t: ty::t) -> ValueRef {
+    /*!
+     * Helper for loading values from memory. Does the necessary conversion if
+     * the in-memory type differs from the type used for SSA values. Also
+     * handles various special cases where the type gives us better information
+     * about what we are loading.
+     */
+    if type_is_zero_size(cx.ccx(), t) {
+        C_undef(type_of::type_of(cx.ccx(), t))
+    } else if ty::type_is_bool(t) {
+        Trunc(cx, LoadRangeAssert(cx, ptr, 0, 2, lib::llvm::False), Type::i1(cx.ccx()))
+    } else if ty::type_is_char(t) {
+        // a char is a unicode codepoint, and so takes values from 0
+        // to 0x10FFFF inclusive only.
+        LoadRangeAssert(cx, ptr, 0, 0x10FFFF + 1, lib::llvm::False)
+    } else {
+        Load(cx, ptr)
+    }
+}
+
+pub fn store_ty(cx: &Block, v: ValueRef, dst: ValueRef, t: ty::t) {
+    /*!
+     * Helper for storing values in memory. Does the necessary conversion if
+     * the in-memory type differs from the type used for SSA values.
+     */
+    if ty::type_is_bool(t) {
+        Store(cx, ZExt(cx, v, Type::i8(cx.ccx())), dst);
+    } else {
+        Store(cx, v, dst);
+    };
+}
+
 pub fn ignore_lhs(_bcx: &Block, local: &ast::Local) -> bool {
     match local.pat.node {
         ast::PatWild => true, _ => false
@@ -1013,7 +1045,7 @@ pub fn call_memcpy(cx: &Block, dst: ValueRef, src: ValueRef, n_bytes: ValueRef,
     let dst_ptr = PointerCast(cx, dst, Type::i8p(ccx));
     let size = IntCast(cx, n_bytes, ccx.int_type);
     let align = C_i32(ccx, align as i32);
-    let volatile = C_i1(ccx, false);
+    let volatile = C_bool(ccx, false);
     Call(cx, memcpy, [dst_ptr, src_ptr, size, align, volatile], []);
 }
 
@@ -1058,7 +1090,7 @@ fn memzero(b: &Builder, llptr: ValueRef, ty: Type) {
     let llzeroval = C_u8(ccx, 0);
     let size = machine::llsize_of(ccx, ty);
     let align = C_i32(ccx, llalign_of_min(ccx, ty) as i32);
-    let volatile = C_i1(ccx, false);
+    let volatile = C_bool(ccx, false);
     b.call(llintrinsicfn, [llptr, llzeroval, size, align, volatile], []);
 }
 
@@ -1282,9 +1314,14 @@ fn copy_args_to_allocas<'a>(fcx: &FunctionContext<'a>,
 // Ties up the llstaticallocas -> llloadenv -> lltop edges,
 // and builds the return block.
 pub fn finish_fn<'a>(fcx: &'a FunctionContext<'a>,
-                     last_bcx: &'a Block<'a>) {
+                     last_bcx: &'a Block<'a>,
+                     retty: ty::t) {
     let _icx = push_ctxt("finish_fn");
 
+    // This shouldn't need to recompute the return type,
+    // as new_fn_ctxt did it already.
+    let substd_retty = retty.substp(fcx.ccx.tcx(), fcx.param_substs);
+
     let ret_cx = match fcx.llreturn.get() {
         Some(llreturn) => {
             if !last_bcx.terminated.get() {
@@ -1294,13 +1331,13 @@ pub fn finish_fn<'a>(fcx: &'a FunctionContext<'a>,
         }
         None => last_bcx
     };
-    build_return_block(fcx, ret_cx);
+    build_return_block(fcx, ret_cx, substd_retty);
     debuginfo::clear_source_location(fcx);
     fcx.cleanup();
 }
 
 // Builds the return block for a function.
-pub fn build_return_block(fcx: &FunctionContext, ret_cx: &Block) {
+pub fn build_return_block(fcx: &FunctionContext, ret_cx: &Block, retty: ty::t) {
     // Return the value if this function immediate; otherwise, return void.
     if fcx.llretptr.get().is_none() || fcx.caller_expects_out_pointer {
         return RetVoid(ret_cx);
@@ -1318,13 +1355,16 @@ pub fn build_return_block(fcx: &FunctionContext, ret_cx: &Block) {
                 retptr.erase_from_parent();
             }
 
-            retval
+            if ty::type_is_bool(retty) {
+                Trunc(ret_cx, retval, Type::i1(fcx.ccx))
+            } else {
+                retval
+            }
         }
         // Otherwise, load the return value from the ret slot
-        None => Load(ret_cx, fcx.llretptr.get().unwrap())
+        None => load_ty(ret_cx, fcx.llretptr.get().unwrap(), retty)
     };
 
-
     Ret(ret_cx, retval);
 }
 
@@ -1422,7 +1462,7 @@ pub fn trans_closure(ccx: &CrateContext,
     }
 
     // Insert the mandatory first few basic blocks before lltop.
-    finish_fn(&fcx, bcx);
+    finish_fn(&fcx, bcx, output_type);
 }
 
 // trans_fn: creates an LLVM function corresponding to a source language
@@ -1512,7 +1552,7 @@ fn trans_enum_variant_or_tuple_like_struct(ccx: &CrateContext,
         }
     }
 
-    finish_fn(&fcx, bcx);
+    finish_fn(&fcx, bcx, result_ty);
 }
 
 fn trans_enum_def(ccx: &CrateContext, enum_definition: &ast::EnumDef,

src/librustc/middle/trans/cabi_arm.rs

@@ -85,7 +85,7 @@ fn ty_size(ty: Type) -> uint {
 
 fn classify_ret_ty(ccx: &CrateContext, ty: Type) -> ArgType {
     if is_reg_ty(ty) {
-        let attr = if ty == Type::bool(ccx) { Some(ZExtAttribute) } else { None };
+        let attr = if ty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
         return ArgType::direct(ty, None, None, attr);
     }
     let size = ty_size(ty);
@@ -104,7 +104,7 @@ fn classify_ret_ty(ccx: &CrateContext, ty: Type) -> ArgType {
 
 fn classify_arg_ty(ccx: &CrateContext, ty: Type) -> ArgType {
     if is_reg_ty(ty) {
-        let attr = if ty == Type::bool(ccx) { Some(ZExtAttribute) } else { None };
+        let attr = if ty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
         return ArgType::direct(ty, None, None, attr);
     }
     let align = ty_align(ty);

src/librustc/middle/trans/cabi_mips.rs

@@ -85,7 +85,7 @@ fn ty_size(ty: Type) -> uint {
 
 fn classify_ret_ty(ccx: &CrateContext, ty: Type) -> ArgType {
     if is_reg_ty(ty) {
-        let attr = if ty == Type::bool(ccx) { Some(ZExtAttribute) } else { None };
+        let attr = if ty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
         ArgType::direct(ty, None, None, attr)
     } else {
         ArgType::indirect(ty, Some(StructRetAttribute))
@@ -102,7 +102,7 @@ fn classify_arg_ty(ccx: &CrateContext, ty: Type, offset: &mut uint) -> ArgType {
     *offset += align_up_to(size, align * 8) / 8;
 
     if is_reg_ty(ty) {
-        let attr = if ty == Type::bool(ccx) { Some(ZExtAttribute) } else { None };
+        let attr = if ty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
         ArgType::direct(ty, None, None, attr)
     } else {
         ArgType::direct(

src/librustc/middle/trans/cabi_x86.rs

@@ -59,7 +59,7 @@ pub fn compute_abi_info(ccx: &CrateContext,
             }
         }
     } else {
-        let attr = if rty == Type::bool(ccx) { Some(ZExtAttribute) } else { None };
+        let attr = if rty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
         ret_ty = ArgType::direct(rty, None, None, attr);
     }
 
@@ -74,7 +74,7 @@ pub fn compute_abi_info(ccx: &CrateContext,
                 }
             }
             _ => {
-                let attr = if t == Type::bool(ccx) { Some(ZExtAttribute) } else { None };
+                let attr = if t == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
                 ArgType::direct(t, None, None, attr)
             }
         };

src/librustc/middle/trans/cabi_x86_64.rs

@@ -350,7 +350,7 @@ pub fn compute_abi_info(ccx: &CrateContext,
                                 None)
             }
         } else {
-            let attr = if ty == Type::bool(ccx) { Some(ZExtAttribute) } else { None };
+            let attr = if ty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
             ArgType::direct(ty, None, None, attr)
         }
     }

src/librustc/middle/trans/callee.rs

@@ -345,7 +345,7 @@ pub fn trans_unboxing_shim(bcx: &Block,
                            }).bcx;
 
     bcx = fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_scope);
-    finish_fn(&fcx, bcx);
+    finish_fn(&fcx, bcx, return_type);
 
     llfn
 }
@@ -757,7 +757,7 @@ pub fn trans_call_inner<'a>(
                 if !type_of::return_uses_outptr(bcx.ccx(), ret_ty) &&
                     !type_is_zero_size(bcx.ccx(), ret_ty)
                 {
-                    Store(bcx, llret, llretslot);
+                    store_ty(bcx, llret, llretslot, ret_ty)
                 }
             }
             None => {}

src/librustc/middle/trans/common.rs

@@ -522,10 +522,6 @@ pub fn C_nil(ccx: &CrateContext) -> ValueRef {
 }
 
 pub fn C_bool(ccx: &CrateContext, val: bool) -> ValueRef {
-    C_integral(Type::bool(ccx), val as u64, false)
-}
-
-pub fn C_i1(ccx: &CrateContext, val: bool) -> ValueRef {
     C_integral(Type::i1(ccx), val as u64, false)
 }
 

src/librustc/middle/trans/datum.rs

@@ -13,10 +13,8 @@
  * Datums are and how they are intended to be used.
  */
 
-use lib;
 use lib::llvm::ValueRef;
 use middle::trans::base::*;
-use middle::trans::build::*;
 use middle::trans::common::*;
 use middle::trans::cleanup;
 use middle::trans::cleanup::CleanupMethods;
@@ -344,7 +342,7 @@ impl Datum<Rvalue> {
                 match self.kind.mode {
                     ByValue => DatumBlock::new(bcx, self),
                     ByRef => {
-                        let llval = load(bcx, self.val, self.ty);
+                        let llval = load_ty(bcx, self.val, self.ty);
                         DatumBlock::new(bcx, Datum::new(llval, self.ty, Rvalue::new(ByValue)))
                     }
                 }
@@ -471,7 +469,7 @@ impl Datum<Expr> {
                         DatumBlock::new(bcx, scratch)
                     }
                     ByValue => {
-                        let v = load(bcx, l.val, l.ty);
+                        let v = load_ty(bcx, l.val, l.ty);
                         bcx = l.kind.post_store(bcx, l.val, l.ty);
                         DatumBlock::new(bcx, Datum::new(v, l.ty, Rvalue::new(ByValue)))
                     }
@@ -516,24 +514,6 @@ impl Datum<Lvalue> {
     }
 }
 
-fn load<'a>(bcx: &'a Block<'a>, llptr: ValueRef, ty: ty::t) -> ValueRef {
-    /*!
-     * Private helper for loading from a by-ref datum. Handles various
-     * special cases where the type gives us better information about
-     * what we are loading.
-     */
-
-    if type_is_zero_size(bcx.ccx(), ty) {
-        C_undef(type_of::type_of(bcx.ccx(), ty))
-    } else if ty::type_is_char(ty) {
-        // a char is a unicode codepoint, and so takes values from 0
-        // to 0x10FFFF inclusive only.
-        LoadRangeAssert(bcx, llptr, 0, 0x10FFFF + 1, lib::llvm::False)
-    } else {
-        Load(bcx, llptr)
-    }
-}
-
 /**
  * Generic methods applicable to any sort of datum.
  */
@@ -591,7 +571,7 @@ impl<K:KindOps> Datum<K> {
         if self.kind.is_by_ref() {
             memcpy_ty(bcx, dst, self.val, self.ty);
         } else {
-            Store(bcx, self.val, dst);
+            store_ty(bcx, self.val, dst, self.ty);
         }
 
         return bcx;
@@ -642,7 +622,7 @@ impl<K:KindOps> Datum<K> {
         assert!(!ty::type_needs_drop(bcx.tcx(), self.ty));
         assert!(self.appropriate_rvalue_mode(bcx.ccx()) == ByValue);
         if self.kind.is_by_ref() {
-            load(bcx, self.val, self.ty)
+            load_ty(bcx, self.val, self.ty)
         } else {
             self.val
         }

src/librustc/middle/trans/expr.rs

@@ -505,7 +505,7 @@ fn trans_index<'a>(bcx: &'a Block<'a>,
 
     let bounds_check = ICmp(bcx, lib::llvm::IntUGE, ix_val, len);
     let expect = ccx.get_intrinsic(&("llvm.expect.i1"));
-    let expected = Call(bcx, expect, [bounds_check, C_i1(ccx, false)], []);
+    let expected = Call(bcx, expect, [bounds_check, C_bool(ccx, false)], []);
     let bcx = with_cond(bcx, expected, |bcx| {
             controlflow::trans_fail_bounds_check(bcx, index_expr.span, ix_val, len)
         });
@@ -1149,13 +1149,7 @@ fn trans_unary<'a>(bcx: &'a Block<'a>,
     match op {
         ast::UnNot => {
             let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
-            let llresult = if ty::type_is_bool(un_ty) {
-                let val = datum.to_llscalarish(bcx);
-                Xor(bcx, val, C_bool(ccx, true))
-            } else {
-                // Note: `Not` is bitwise, not suitable for logical not.
-                Not(bcx, datum.to_llscalarish(bcx))
-            };
+            let llresult = Not(bcx, datum.to_llscalarish(bcx));
             immediate_rvalue_bcx(bcx, llresult, un_ty).to_expr_datumblock()
         }
         ast::UnNeg => {
@@ -1380,7 +1374,7 @@ fn trans_lazy_binop<'a>(
     }
 
     Br(past_rhs, join.llbb);
-    let phi = Phi(join, Type::bool(bcx.ccx()), [lhs, rhs],
+    let phi = Phi(join, Type::i1(bcx.ccx()), [lhs, rhs],
                   [past_lhs.llbb, past_rhs.llbb]);
 
     return immediate_rvalue_bcx(join, phi, binop_ty).to_expr_datumblock();
@@ -1597,8 +1591,8 @@ fn trans_imm_cast<'a>(bcx: &'a Block<'a>,
     let k_in = cast_type_kind(t_in);
     let k_out = cast_type_kind(t_out);
     let s_in = k_in == cast_integral && ty::type_is_signed(t_in);
-    let ll_t_in = type_of::type_of(ccx, t_in);
-    let ll_t_out = type_of::type_of(ccx, t_out);
+    let ll_t_in = type_of::arg_type_of(ccx, t_in);
+    let ll_t_out = type_of::arg_type_of(ccx, t_out);
 
     // Convert the value to be cast into a ValueRef, either by-ref or
     // by-value as appropriate given its type:
@@ -1689,7 +1683,7 @@ fn trans_assign_op<'a>(
     let dst_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign_op"));
     assert!(!ty::type_needs_drop(bcx.tcx(), dst_datum.ty));
     let dst_ty = dst_datum.ty;
-    let dst = Load(bcx, dst_datum.val);
+    let dst = load_ty(bcx, dst_datum.val, dst_datum.ty);
 
     // Evaluate RHS
     let rhs_datum = unpack_datum!(bcx, trans(bcx, &*src));