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Created March 7, 2014 16:22
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PR-12610.diff
commit 23a1d59063159b233cfb559f77c6149df5be62d6
Author: Niko Matsakis <[email protected]>
Date: Fri Mar 7 11:10:14 2014 -0500
WIP nits
diff --git a/src/librustc/middle/trans/callee.rs b/src/librustc/middle/trans/callee.rs
index a48c640..ad7a418 100644
--- a/src/librustc/middle/trans/callee.rs
+++ b/src/librustc/middle/trans/callee.rs
@@ -171,10 +171,13 @@ pub fn trans_fn_ref(bcx: &Block, def_id: ast::DefId, node: ExprOrMethodCall) ->
let type_params = node_id_type_params(bcx, node);
let vtables = match node {
ExprId(id) => node_vtables(bcx, id),
- MethodCall(method_call) if method_call.autoderef == 0 => {
- node_vtables(bcx, method_call.expr_id)
+ MethodCall(ref method_call) => {
+ if method_call.autoderef == 0 {
+ node_vtables(bcx, method_call.expr_id)
+ } else {
+ None
+ }
}
- _ => None
};
debug!("trans_fn_ref(def_id={}, node={:?}, type_params={}, vtables={})",
def_id.repr(bcx.tcx()), node, type_params.repr(bcx.tcx()),
@@ -376,15 +379,15 @@ pub fn trans_fn_ref_with_vtables(
// Should be either intra-crate or inlined.
assert_eq!(def_id.krate, ast::LOCAL_CRATE);
- let ref_id = match node {
- ExprId(id) if id != 0 => Some(id),
- _ => None
+ let opt_ref_id = match node {
+ ExprId(id) => if id != 0 { Some(id) } else { None },
+ MethodCall(_) => None,
};
let (val, must_cast) =
monomorphize::monomorphic_fn(ccx, def_id, &substs,
vtables, self_vtables,
- ref_id);
+ opt_ref_id);
let mut val = val;
if must_cast && node != ExprId(0) {
// Monotype of the REFERENCE to the function (type params
@@ -748,9 +751,19 @@ pub fn trans_call_inner<'a>(
}
pub enum CallArgs<'a> {
+ // Supply value of arguments as a list of expressions that must be
+ // translated. This is used in the common case of `foo(bar, qux)`.
ArgExprs(&'a [@ast::Expr]),
+
+ // Supply value of arguments as a list of LLVM value refs; frequently
+ // used with lang items and so forth, when the argument is an internal
+ // value.
+ ArgVals(&'a [ValueRef]),
+
+ // For overloaded operators: `(lhs, Option(rhs, rhs_id))`. `lhs`
+ // is the left-hand-side and `rhs/rhs_id` is the datum/expr-id of
+ // the right-hand-side (if any).
ArgOverloadedOp(Datum<Expr>, Option<(Datum<Expr>, ast::NodeId)>),
- ArgVals(&'a [ValueRef])
}
fn trans_args<'a>(cx: &'a Block<'a>,
diff --git a/src/librustc/middle/trans/common.rs b/src/librustc/middle/trans/common.rs
index bb8b62a..2d231d8 100644
--- a/src/librustc/middle/trans/common.rs
+++ b/src/librustc/middle/trans/common.rs
@@ -807,9 +807,16 @@ pub fn expr_ty_adjusted(bcx: &Block, ex: &ast::Expr) -> ty::t {
monomorphize_type(bcx, t)
}
+// Meta comment: This looks fine for now, but I feel like there is a way
+// to better align our lookup tables so that we don't need this type.
+
+// Key used to lookup values supplied for type parameters in an expr.
#[deriving(Eq)]
pub enum ExprOrMethodCall {
+ // Type parameters for a path like `None::<int>`
ExprId(ast::NodeId),
+
+ // Type parameters for a method call like `a.foo::<int>()`
MethodCall(typeck::MethodCall)
}
diff --git a/src/librustc/middle/trans/expr.rs b/src/librustc/middle/trans/expr.rs
index 207d889..8fe4117 100644
--- a/src/librustc/middle/trans/expr.rs
+++ b/src/librustc/middle/trans/expr.rs
@@ -1159,9 +1159,13 @@ fn trans_unary<'a>(bcx: &'a Block<'a>,
let _icx = push_ctxt("trans_unary_datum");
let method_call = MethodCall::expr(expr.id);
- let overloaded = bcx.ccx().maps.method_map.borrow().get().contains_key(&method_call);
- // if overloaded, would be RvalueDpsExpr
- assert!(!overloaded || op == ast::UnDeref);
+
+ // The only overloaded operator that is translated to a datum
+ // is an overloaded deref, since it is always yields a `&T`.
+ // Otherwise, we should be in the RvalueDpsExpr path.
+ assert!(
+ op == ast::UnDeref ||
+ !bcx.ccx().maps.method_map.borrow().get().contains_key(&method_call));
let un_ty = expr_ty(bcx, expr);
@@ -1778,6 +1782,7 @@ fn deref_once<'a>(bcx: &'a Block<'a>,
let mut bcx = bcx;
+ // Check for overloaded deref.
let method_call = MethodCall {
expr_id: expr.id,
autoderef: derefs as u32
@@ -1786,6 +1791,11 @@ fn deref_once<'a>(bcx: &'a Block<'a>,
.find(&method_call).map(|method| method.ty);
let datum = match method_ty {
Some(method_ty) => {
+ // Overloaded. Evaluate `trans_overloaded_op`, which will
+ // invoke the user's deref() method, which basically
+ // converts from the `Shaht<T>` pointer that we have into
+ // a `&T` pointer. We can then proceed down the normal
+ // path (below) to dereference that `&T`.
let datum = if derefs == 0 {
datum
} else {
@@ -1797,7 +1807,10 @@ fn deref_once<'a>(bcx: &'a Block<'a>,
let ref_ty = ty::ty_fn_ret(monomorphize_type(bcx, method_ty));
Datum(val, ref_ty, RvalueExpr(Rvalue(ByValue)))
}
- None => datum
+ None => {
+ // Not overloaded. We already have a pointer we know how to deref.
+ datum
+ }
};
let r = match ty::get(datum.ty).sty {
diff --git a/src/librustc/middle/trans/meth.rs b/src/librustc/middle/trans/meth.rs
index 703c7a9..d783e0d 100644
--- a/src/librustc/middle/trans/meth.rs
+++ b/src/librustc/middle/trans/meth.rs
@@ -335,10 +335,13 @@ fn combine_impl_and_methods_tps(bcx: &Block,
// exist, in which case we need to make them.
let vtables = match node {
ExprId(id) => node_vtables(bcx, id),
- MethodCall(method_call) if method_call.autoderef == 0 => {
- node_vtables(bcx, method_call.expr_id)
+ MethodCall(method_call) => {
+ if method_call.autoderef == 0 {
+ node_vtables(bcx, method_call.expr_id)
+ } else {
+ None
+ }
}
- _ => None
};
let r_m_origins = match vtables {
Some(vt) => vt,
diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 0628900..5baa8cd 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -223,7 +223,7 @@ pub struct AutoDerefRef {
autoref: Option<AutoRef>
}
-#[deriving(Decodable, Encodable)]
+#[deriving(Decodable, Encodable, Eq, Show)]
pub enum AutoRef {
/// Convert from T to &T
AutoPtr(Region, ast::Mutability),
@@ -3261,11 +3261,15 @@ pub fn expr_kind(tcx: ctxt,
expr: &ast::Expr) -> ExprKind {
if method_map.borrow().get().contains_key(&MethodCall::expr(expr.id)) {
// Overloaded operations are generally calls, and hence they are
- // generated via DPS. However, assign_op (e.g., `x += y`) is an
- // exception, as its result is always unit.
+ // generated via DPS, but there are two exceptions:
return match expr.node {
+ // `a += b` has a unit result.
ast::ExprAssignOp(..) => RvalueStmtExpr,
+
+ // the deref method invoked for `*a` always yields an `&T`
ast::ExprUnary(ast::UnDeref, _) => LvalueExpr,
+
+ // in the general case, result could be any type, use DPS
_ => RvalueDpsExpr
};
}
diff --git a/src/librustc/middle/typeck/check/method.rs b/src/librustc/middle/typeck/check/method.rs
index dd3ef4b..435a939 100644
--- a/src/librustc/middle/typeck/check/method.rs
+++ b/src/librustc/middle/typeck/check/method.rs
@@ -200,7 +200,13 @@ pub fn lookup_in_trait<'a>(
struct LookupContext<'a> {
fcx: @FnCtxt,
span: Span,
+
+ // The receiver to the method call. Only `None` in the case of
+ // an overloaded autoderef, where the receiver may be an intermediate
+ // state like "the expression `x` when it has been autoderef'd
+ // twice already".
self_expr: Option<&'a ast::Expr>,
+
m_name: ast::Name,
supplied_tps: &'a [ty::t],
impl_dups: @RefCell<HashSet<DefId>>,
@@ -242,51 +248,69 @@ impl<'a> LookupContext<'a> {
let span = self.self_expr.map_or(self.span, |e| e.span);
let self_expr_id = self.self_expr.map(|e| e.id);
let (self_ty, autoderefs, result) =
- check::autoderef(self.fcx, span, self_ty, self_expr_id,
- PreferMutLvalue, |self_ty, autoderefs| {
-
- debug!("loop: self_ty={} autoderefs={}",
- self.ty_to_str(self_ty), autoderefs);
+ check::autoderef(
+ self.fcx, span, self_ty, self_expr_id, PreferMutLvalue,
+ |self_ty, autoderefs| self.search_step(self_ty, autoderefs));
- match self.deref_args {
- check::DontDerefArgs => {
- match self.search_for_autoderefd_method(self_ty, autoderefs) {
- Some(result) => return Some(Some(result)),
- None => {}
- }
+ match result {
+ Some(Some(result)) => Some(result),
+ _ => {
+ if self.is_overloaded_deref() {
+ // If we are searching for an overloaded deref, no
+ // need to try coercing a `~[T]` to an `&[T]` and
+ // searching for an overloaded deref on *that*.
+ None
+ } else {
+ self.search_for_autosliced_method(self_ty, autoderefs)
+ }
+ }
+ }
+ }
- match self.search_for_autoptrd_method(self_ty, autoderefs) {
- Some(result) => return Some(Some(result)),
- None => {}
- }
+ fn search_step(&self,
+ self_ty: ty::t,
+ autoderefs: uint)
+ -> Option<Option<MethodCallee>> {
+ debug!("search_step: self_ty={} autoderefs={}",
+ self.ty_to_str(self_ty), autoderefs);
+
+ match self.deref_args {
+ check::DontDerefArgs => {
+ match self.search_for_autoderefd_method(self_ty, autoderefs) {
+ Some(result) => return Some(Some(result)),
+ None => {}
}
- check::DoDerefArgs => {
- match self.search_for_autoptrd_method(self_ty, autoderefs) {
- Some(result) => return Some(Some(result)),
- None => {}
- }
- match self.search_for_autoderefd_method(self_ty, autoderefs) {
- Some(result) => return Some(Some(result)),
- None => {}
- }
+ match self.search_for_autoptrd_method(self_ty, autoderefs) {
+ Some(result) => return Some(Some(result)),
+ None => {}
}
}
+ check::DoDerefArgs => {
+ match self.search_for_autoptrd_method(self_ty, autoderefs) {
+ Some(result) => return Some(Some(result)),
+ None => {}
+ }
- // Don't autoderef if we aren't supposed to.
- if self.autoderef_receiver == DontAutoderefReceiver {
- Some(None)
- } else {
- None
+ match self.search_for_autoderefd_method(self_ty, autoderefs) {
+ Some(result) => return Some(Some(result)),
+ None => {}
+ }
}
- });
+ }
- match result {
- Some(Some(result)) => Some(result),
- _ => self.search_for_autosliced_method(self_ty, autoderefs)
+ // Don't autoderef if we aren't supposed to.
+ if self.autoderef_receiver == DontAutoderefReceiver {
+ Some(None)
+ } else {
+ None
}
}
+ fn is_overloaded_deref(&self) -> bool {
+ self.self_expr.is_none()
+ }
+
// ______________________________________________________________________
// Candidate collection (see comment at start of file)
@@ -615,17 +639,13 @@ impl<'a> LookupContext<'a> {
let (self_ty, auto_deref_ref) =
self.consider_reborrow(self_ty, autoderefs);
- // HACK(eddyb) only overloaded auto-deref calls should be missing
- // adjustments, because we imply an AutoPtr adjustment for them.
- let adjustment = match auto_deref_ref {
- ty::AutoDerefRef {
- autoderefs: 0,
- autoref: Some(ty::AutoPtr(..))
- } => None,
- _ => match self.self_expr {
- Some(expr) => Some((expr.id, @ty::AutoDerefRef(auto_deref_ref))),
- None => return None
- }
+ // Hacky. For overloaded derefs, there may be an adjustment
+ // added to the expression from the outside context, so we do not store
+ // an explicit adjustment, but rather we hardwire the single deref
+ // that occurs in trans and mem_categorization.
+ let adjustment = match self.self_expr {
+ Some(expr) => Some((expr.id, @ty::AutoDerefRef(auto_deref_ref))),
+ None => return None
};
match self.search_for_method(self_ty) {
@@ -723,9 +743,9 @@ impl<'a> LookupContext<'a> {
autoderefs: uint)
-> Option<MethodCallee> {
/*!
- *
* Searches for a candidate by converting things like
- * `~[]` to `&[]`. */
+ * `~[]` to `&[]`.
+ */
let tcx = self.tcx();
let sty = ty::get(self_ty).sty.clone();
@@ -833,15 +853,20 @@ impl<'a> LookupContext<'a> {
mutbls: &[ast::Mutability],
mk_autoref_ty: |ast::Mutability, ty::Region| -> ty::t)
-> Option<MethodCallee> {
- // HACK(eddyb) only overloaded auto-deref calls should be missing
- // adjustments, because we imply an AutoPtr adjustment for them.
+ // Hacky. For overloaded derefs, there may be an adjustment
+ // added to the expression from the outside context, so we do not store
+ // an explicit adjustment, but rather we hardwire the single deref
+ // that occurs in trans and mem_categorization.
let self_expr_id = match self.self_expr {
Some(expr) => Some(expr.id),
- None => match kind(ty::ReEmpty, ast::MutImmutable) {
- ty::AutoPtr(..) if autoderefs == 0 => None,
- _ => return None
+ None => {
+ assert_eq!(autoderefs, 0);
+ assert_eq!(kind(ty::ReEmpty, ast::MutImmutable),
+ ty::AutoPtr(ty::ReEmpty, ast::MutImmutable));
+ None
}
};
+
// This is hokey. We should have mutability inference as a
// variable. But for now, try &const, then &, then &mut:
let region =
@@ -898,7 +923,8 @@ impl<'a> LookupContext<'a> {
}
}
- fn consider_candidates(&self, rcvr_ty: ty::t,
+ fn consider_candidates(&self,
+ rcvr_ty: ty::t,
candidates: &mut ~[Candidate])
-> Option<MethodCallee> {
// FIXME(pcwalton): Do we need to clone here?
@@ -1090,7 +1116,8 @@ impl<'a> LookupContext<'a> {
&self,
trait_def_id: ast::DefId,
rcvr_substs: &ty::substs,
- method_ty: &ty::Method) -> ty::t {
+ method_ty: &ty::Method)
+ -> ty::t {
/*!
* This is a bit tricky. We have a match against a trait method
* being invoked on an object, and we want to generate the
diff --git a/src/librustc/middle/typeck/check/mod.rs b/src/librustc/middle/typeck/check/mod.rs
index c05eae4..2faf358 100644
--- a/src/librustc/middle/typeck/check/mod.rs
+++ b/src/librustc/middle/typeck/check/mod.rs
@@ -1243,11 +1243,14 @@ pub fn autoderef<T>(fcx: @FnCtxt, sp: Span, base_ty: ty::t,
should_stop: |ty::t, uint| -> Option<T>)
-> (ty::t, uint, Option<T>) {
/*!
+ * Executes an autoderef loop for the type `t`. At each step, invokes
+ * `should_stop` to decide whether to terminate the loop. Returns
+ * the final type and number of derefs that it performed.
*
- * Autoderefs the type `t` as many times as possible, returning a new type
- * and an autoderef count. If the count is not zero, the receiver is
- * responsible for inserting an AutoAdjustment record into `tcx.adjustments`
- * so that trans/borrowck/etc know about this autoderef. */
+ * Note: this method does not modify the adjustments table. The caller is
+ * responsible for inserting an AutoAdjustment record into the `fcx`
+ * using one of the suitable methods.
+ */
let mut t = base_ty;
for autoderefs in range(0, fcx.tcx().sess.recursion_limit.get()) {
@@ -2281,15 +2284,15 @@ fn check_expr_with_unifier(fcx: @FnCtxt,
fcx.expr_ty(base));
let (_, autoderefs, field_ty) =
autoderef(fcx, expr.span, expr_t, Some(base.id), lvalue_pref, |base_t, _| {
- match ty::get(base_t).sty {
- ty::ty_struct(base_id, ref substs) => {
- debug!("struct named {}", ppaux::ty_to_str(tcx, base_t));
- let fields = ty::lookup_struct_fields(tcx, base_id);
- lookup_field_ty(tcx, base_id, fields, field, &(*substs))
+ match ty::get(base_t).sty {
+ ty::ty_struct(base_id, ref substs) => {
+ debug!("struct named {}", ppaux::ty_to_str(tcx, base_t));
+ let fields = ty::lookup_struct_fields(tcx, base_id);
+ lookup_field_ty(tcx, base_id, fields, field, &(*substs))
+ }
+ _ => None
}
- _ => None
- }
- });
+ });
match field_ty {
Some(field_ty) => {
fcx.write_ty(expr.id, field_ty);
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 7efae93..42818fc 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -387,7 +387,7 @@ pub enum Pat_ {
PatVec(Vec<@Pat> , Option<@Pat>, Vec<@Pat> )
}
-#[deriving(Clone, Eq, Encodable, Decodable, Hash)]
+#[deriving(Clone, Eq, Encodable, Decodable, Hash, Show)]
pub enum Mutability {
MutMutable,
MutImmutable,
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