From 8a17b36fc5cdd33fdd8a705b82118980b48681f7 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 15 Jul 2018 11:35:18 +0200
Subject: [PATCH 1/4] CTFE: use binary_op to compare integer with match
disriminant
---
src/librustc_mir/interpret/terminator/mod.rs | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/src/librustc_mir/interpret/terminator/mod.rs b/src/librustc_mir/interpret/terminator/mod.rs
index 2994b1b387f3f..e281ba7963979 100644
--- a/src/librustc_mir/interpret/terminator/mod.rs
+++ b/src/librustc_mir/interpret/terminator/mod.rs
@@ -1,10 +1,10 @@
use rustc::mir;
use rustc::ty::{self, Ty};
-use rustc::ty::layout::LayoutOf;
+use rustc::ty::layout::{LayoutOf, Size};
use syntax::codemap::Span;
use rustc_target::spec::abi::Abi;
-use rustc::mir::interpret::EvalResult;
+use rustc::mir::interpret::{EvalResult, Scalar};
use super::{EvalContext, Place, Machine, ValTy};
use rustc_data_structures::indexed_vec::Idx;
@@ -41,13 +41,18 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
let discr_prim = self.value_to_scalar(discr_val)?;
let discr_layout = self.layout_of(discr_val.ty).unwrap();
trace!("SwitchInt({:?}, {:#?})", discr_prim, discr_layout);
- let discr_prim = discr_prim.to_bits(discr_layout.size)?;
// Branch to the `otherwise` case by default, if no match is found.
let mut target_block = targets[targets.len() - 1];
for (index, &const_int) in values.iter().enumerate() {
- if discr_prim == const_int {
+ // Compare using binary_op
+ let const_int = Scalar::Bits { bits: const_int, defined: 128 };
+ let res = self.binary_op(mir::BinOp::Eq,
+ discr_prim, discr_val.ty,
+ const_int, discr_val.ty
+ )?;
+ if res.0.to_bits(Size::from_bytes(1))? != 0 {
target_block = targets[index];
break;
}
From 5be74148c23d41e306446d23acb93ed93e095252 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 15 Jul 2018 13:55:17 +0200
Subject: [PATCH 2/4] add test case
---
src/test/ui/const-eval/match-test-ptr-null.rs | 12 ++++++++
.../ui/const-eval/match-test-ptr-null.stderr | 30 +++++++++++++++++++
2 files changed, 42 insertions(+)
create mode 100644 src/test/ui/const-eval/match-test-ptr-null.rs
create mode 100644 src/test/ui/const-eval/match-test-ptr-null.stderr
diff --git a/src/test/ui/const-eval/match-test-ptr-null.rs b/src/test/ui/const-eval/match-test-ptr-null.rs
new file mode 100644
index 0000000000000..3e8a5930a1d20
--- /dev/null
+++ b/src/test/ui/const-eval/match-test-ptr-null.rs
@@ -0,0 +1,12 @@
+fn main() {
+ // Make sure match uses the usual pointer comparison code path -- i.e., it should complain
+ // that pointer comparison is disallowed, not that parts of a pointer are accessed as raw
+ // bytes.
+ let _: [u8; 0] = [4; { //~ ERROR could not evaluate repeat length
+ match &1 as *const i32 as usize { //~ ERROR raw pointers cannot be cast to integers
+ 0 => 42, //~ ERROR constant contains unimplemented expression type
+ //~^ NOTE "pointer arithmetic or comparison" needs an rfc before being allowed
+ n => n,
+ }
+ }];
+}
diff --git a/src/test/ui/const-eval/match-test-ptr-null.stderr b/src/test/ui/const-eval/match-test-ptr-null.stderr
new file mode 100644
index 0000000000000..ffc911a2ae2e6
--- /dev/null
+++ b/src/test/ui/const-eval/match-test-ptr-null.stderr
@@ -0,0 +1,30 @@
+error[E0018]: raw pointers cannot be cast to integers in constants
+ --> $DIR/match-test-ptr-null.rs:6:15
+ |
+LL | match &1 as *const i32 as usize { //~ ERROR raw pointers cannot be cast to integers
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0019]: constant contains unimplemented expression type
+ --> $DIR/match-test-ptr-null.rs:7:13
+ |
+LL | 0 => 42, //~ ERROR constant contains unimplemented expression type
+ | ^
+
+error[E0080]: could not evaluate repeat length
+ --> $DIR/match-test-ptr-null.rs:5:26
+ |
+LL | let _: [u8; 0] = [4; { //~ ERROR could not evaluate repeat length
+ | __________________________^
+LL | | match &1 as *const i32 as usize { //~ ERROR raw pointers cannot be cast to integers
+LL | | 0 => 42, //~ ERROR constant contains unimplemented expression type
+ | | - "pointer arithmetic or comparison" needs an rfc before being allowed inside constants
+LL | | //~^ NOTE "pointer arithmetic or comparison" needs an rfc before being allowed
+LL | | n => n,
+LL | | }
+LL | | }];
+ | |_____^
+
+error: aborting due to 3 previous errors
+
+Some errors occurred: E0018, E0019, E0080.
+For more information about an error, try `rustc --explain E0018`.
From 03b9020155033c2721206c4b4446b888fb5617c9 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 15 Jul 2018 14:26:31 +0200
Subject: [PATCH 3/4] add license text
---
src/test/ui/const-eval/match-test-ptr-null.rs | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/src/test/ui/const-eval/match-test-ptr-null.rs b/src/test/ui/const-eval/match-test-ptr-null.rs
index 3e8a5930a1d20..19b3dcc318154 100644
--- a/src/test/ui/const-eval/match-test-ptr-null.rs
+++ b/src/test/ui/const-eval/match-test-ptr-null.rs
@@ -1,3 +1,13 @@
+// Copyright 2018 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() {
// Make sure match uses the usual pointer comparison code path -- i.e., it should complain
// that pointer comparison is disallowed, not that parts of a pointer are accessed as raw
From f9825c215b9b76dd42504e72887f82eca0469c96 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 15 Jul 2018 20:42:18 +0200
Subject: [PATCH 4/4] fix line numbers
---
src/test/ui/const-eval/match-test-ptr-null.stderr | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/src/test/ui/const-eval/match-test-ptr-null.stderr b/src/test/ui/const-eval/match-test-ptr-null.stderr
index ffc911a2ae2e6..726ada9b428aa 100644
--- a/src/test/ui/const-eval/match-test-ptr-null.stderr
+++ b/src/test/ui/const-eval/match-test-ptr-null.stderr
@@ -1,17 +1,17 @@
error[E0018]: raw pointers cannot be cast to integers in constants
- --> $DIR/match-test-ptr-null.rs:6:15
+ --> $DIR/match-test-ptr-null.rs:16:15
|
LL | match &1 as *const i32 as usize { //~ ERROR raw pointers cannot be cast to integers
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0019]: constant contains unimplemented expression type
- --> $DIR/match-test-ptr-null.rs:7:13
+ --> $DIR/match-test-ptr-null.rs:17:13
|
LL | 0 => 42, //~ ERROR constant contains unimplemented expression type
| ^
error[E0080]: could not evaluate repeat length
- --> $DIR/match-test-ptr-null.rs:5:26
+ --> $DIR/match-test-ptr-null.rs:15:26
|
LL | let _: [u8; 0] = [4; { //~ ERROR could not evaluate repeat length
| __________________________^