diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs index f34bfbeab3b47..4a635d19422db 100644 --- a/src/librustc_mir/transform/const_prop.rs +++ b/src/librustc_mir/transform/const_prop.rs @@ -8,7 +8,7 @@ use rustc::hir::def::DefKind; use rustc::hir::def_id::DefId; use rustc::mir::{ AggregateKind, Constant, Location, Place, PlaceBase, Body, Operand, Rvalue, - Local, NullOp, UnOp, StatementKind, Statement, LocalKind, + Local, UnOp, StatementKind, Statement, LocalKind, TerminatorKind, Terminator, ClearCrossCrate, SourceInfo, BinOp, SourceScope, SourceScopeLocalData, LocalDecl, BasicBlock, }; @@ -118,7 +118,7 @@ impl<'tcx> MirPass<'tcx> for ConstProp { struct ConstPropMachine; impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine { - type MemoryKinds= !; + type MemoryKinds = !; type PointerTag = (); type ExtraFnVal = !; @@ -459,97 +459,81 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { ) -> Option> { let span = source_info.span; - // if this isn't a supported operation, then return None - match rvalue { - Rvalue::Repeat(..) | - Rvalue::Aggregate(..) | - Rvalue::NullaryOp(NullOp::Box, _) | - Rvalue::Discriminant(..) => return None, - - Rvalue::Use(_) | - Rvalue::Len(_) | - Rvalue::Cast(..) | - Rvalue::NullaryOp(..) | - Rvalue::CheckedBinaryOp(..) | - Rvalue::Ref(..) | - Rvalue::UnaryOp(..) | - Rvalue::BinaryOp(..) => { } - } - // perform any special checking for specific Rvalue types - if let Rvalue::UnaryOp(op, arg) = rvalue { - trace!("checking UnaryOp(op = {:?}, arg = {:?})", op, arg); - let overflow_check = self.tcx.sess.overflow_checks(); - - self.use_ecx(source_info, |this| { - // We check overflow in debug mode already - // so should only check in release mode. - if *op == UnOp::Neg && !overflow_check { - let ty = arg.ty(&this.local_decls, this.tcx); - - if ty.is_integral() { - let arg = this.ecx.eval_operand(arg, None)?; - let prim = this.ecx.read_immediate(arg)?; - // Need to do overflow check here: For actual CTFE, MIR - // generation emits code that does this before calling the op. - if prim.to_bits()? == (1 << (prim.layout.size.bits() - 1)) { - throw_panic!(OverflowNeg) + match rvalue { + Rvalue::UnaryOp(UnOp::Neg, arg) => { + trace!("checking UnaryOp(op = Neg, arg = {:?})", arg); + let overflow_check = self.tcx.sess.overflow_checks(); + + self.use_ecx(source_info, |this| { + // We check overflow in debug mode already + // so should only check in release mode. + if !overflow_check { + let ty = arg.ty(&this.local_decls, this.tcx); + + if ty.is_integral() { + let arg = this.ecx.eval_operand(arg, None)?; + let prim = this.ecx.read_immediate(arg)?; + // Need to do overflow check here: For actual CTFE, MIR + // generation emits code that does this before calling the op. + if prim.to_bits()? == (1 << (prim.layout.size.bits() - 1)) { + throw_panic!(OverflowNeg) + } } } - } - Ok(()) - })?; - } else if let Rvalue::BinaryOp(op, left, right) = rvalue { - trace!("checking BinaryOp(op = {:?}, left = {:?}, right = {:?})", op, left, right); - - let r = self.use_ecx(source_info, |this| { - this.ecx.read_immediate(this.ecx.eval_operand(right, None)?) - })?; - if *op == BinOp::Shr || *op == BinOp::Shl { - let left_bits = place_layout.size.bits(); - let right_size = r.layout.size; - let r_bits = r.to_scalar().and_then(|r| r.to_bits(right_size)); - if r_bits.ok().map_or(false, |b| b >= left_bits as u128) { - let source_scope_local_data = match self.source_scope_local_data { - ClearCrossCrate::Set(ref data) => data, - ClearCrossCrate::Clear => return None, - }; - let dir = if *op == BinOp::Shr { - "right" - } else { - "left" - }; - let hir_id = source_scope_local_data[source_info.scope].lint_root; - self.tcx.lint_hir( - ::rustc::lint::builtin::EXCEEDING_BITSHIFTS, - hir_id, - span, - &format!("attempt to shift {} with overflow", dir)); - return None; - } + Ok(()) + })?; } - self.use_ecx(source_info, |this| { - let l = this.ecx.read_immediate(this.ecx.eval_operand(left, None)?)?; - let (_, overflow, _ty) = this.ecx.overflowing_binary_op(*op, l, r)?; - - // We check overflow in debug mode already - // so should only check in release mode. - if !this.tcx.sess.overflow_checks() && overflow { - let err = err_panic!(Overflow(*op)).into(); - return Err(err); + + Rvalue::BinaryOp(op, left, right) => { + trace!("checking BinaryOp(op = {:?}, left = {:?}, right = {:?})", op, left, right); + + let r = self.use_ecx(source_info, |this| { + this.ecx.read_immediate(this.ecx.eval_operand(right, None)?) + })?; + if *op == BinOp::Shr || *op == BinOp::Shl { + let left_bits = place_layout.size.bits(); + let right_size = r.layout.size; + let r_bits = r.to_scalar().and_then(|r| r.to_bits(right_size)); + if r_bits.ok().map_or(false, |b| b >= left_bits as u128) { + let source_scope_local_data = match self.source_scope_local_data { + ClearCrossCrate::Set(ref data) => data, + ClearCrossCrate::Clear => return None, + }; + let dir = if *op == BinOp::Shr { + "right" + } else { + "left" + }; + let hir_id = source_scope_local_data[source_info.scope].lint_root; + self.tcx.lint_hir( + ::rustc::lint::builtin::EXCEEDING_BITSHIFTS, + hir_id, + span, + &format!("attempt to shift {} with overflow", dir)); + return None; + } } + self.use_ecx(source_info, |this| { + let l = this.ecx.read_immediate(this.ecx.eval_operand(left, None)?)?; + let (_, overflow, _ty) = this.ecx.overflowing_binary_op(*op, l, r)?; + + // We check overflow in debug mode already + // so should only check in release mode. + if !this.tcx.sess.overflow_checks() && overflow { + let err = err_panic!(Overflow(*op)).into(); + return Err(err); + } - Ok(()) - })?; - } else if let Rvalue::Ref(_, _, place) = rvalue { - trace!("checking Ref({:?})", place); - // FIXME(wesleywiser) we don't currently handle the case where we try to make a ref - // from a function argument that hasn't been assigned to in this function. - if let Place { - base: PlaceBase::Local(local), - projection: box [] - } = place { + Ok(()) + })?; + } + + Rvalue::Ref(_, _, Place { base: PlaceBase::Local(local), projection: box [] }) => { + trace!("checking Ref({:?})", place); + // FIXME(wesleywiser) we don't currently handle the case where we try to make a ref + // from a function argument that hasn't been assigned to in this function. let alive = if let LocalValue::Live(_) = self.ecx.frame().locals[*local].value { true @@ -560,6 +544,14 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { return None; } } + + Rvalue::Aggregate(_, operands) if operands.len() == 0 => { + // FIXME(wesleywiser): const eval will turn this into a `const Scalar()` that + // `SimplifyLocals` doesn't know it can remove. + return None; + } + + _ => { } } self.use_ecx(source_info, |this| { diff --git a/src/test/compile-fail/consts/const-err3.rs b/src/test/compile-fail/consts/const-err3.rs index fc10824f0c03c..add4eef13c784 100644 --- a/src/test/compile-fail/consts/const-err3.rs +++ b/src/test/compile-fail/consts/const-err3.rs @@ -14,6 +14,7 @@ fn main() { //~^ ERROR const_err let _e = [5u8][1]; //~^ ERROR const_err + //~| ERROR this expression will panic at runtime black_box(b); black_box(c); black_box(d); diff --git a/src/test/mir-opt/const_prop/aggregate.rs b/src/test/mir-opt/const_prop/aggregate.rs new file mode 100644 index 0000000000000..0937d37be6b6e --- /dev/null +++ b/src/test/mir-opt/const_prop/aggregate.rs @@ -0,0 +1,25 @@ +// compile-flags: -O + +fn main() { + let x = (0, 1, 2).1 + 0; +} + +// END RUST SOURCE +// START rustc.main.ConstProp.before.mir +// bb0: { +// ... +// _3 = (const 0i32, const 1i32, const 2i32); +// _2 = (_3.1: i32); +// _1 = Add(move _2, const 0i32); +// ... +// } +// END rustc.main.ConstProp.before.mir +// START rustc.main.ConstProp.after.mir +// bb0: { +// ... +// _3 = (const 0i32, const 1i32, const 2i32); +// _2 = const 1i32; +// _1 = Add(move _2, const 0i32); +// ... +// } +// END rustc.main.ConstProp.after.mir diff --git a/src/test/mir-opt/const_prop/boxes.rs b/src/test/mir-opt/const_prop/boxes.rs new file mode 100644 index 0000000000000..52a7f7ee79503 --- /dev/null +++ b/src/test/mir-opt/const_prop/boxes.rs @@ -0,0 +1,53 @@ +// compile-flags: -O + +#![feature(box_syntax)] + +// Note: this test verifies that we, in fact, do not const prop `box` + +fn main() { + let x = *(box 42) + 0; +} + +// END RUST SOURCE +// START rustc.main.ConstProp.before.mir +// bb0: { +// ... +// _4 = Box(i32); +// (*_4) = const 42i32; +// _3 = move _4; +// ... +// _2 = (*_3); +// _1 = Add(move _2, const 0i32); +// ... +// drop(_3) -> [return: bb2, unwind: bb1]; +// } +// bb1 (cleanup): { +// resume; +// } +// bb2: { +// ... +// _0 = (); +// ... +// } +// END rustc.main.ConstProp.before.mir +// START rustc.main.ConstProp.after.mir +// bb0: { +// ... +// _4 = Box(i32); +// (*_4) = const 42i32; +// _3 = move _4; +// ... +// _2 = (*_3); +// _1 = Add(move _2, const 0i32); +// ... +// drop(_3) -> [return: bb2, unwind: bb1]; +// } +// bb1 (cleanup): { +// resume; +// } +// bb2: { +// ... +// _0 = (); +// ... +// } +// END rustc.main.ConstProp.after.mir diff --git a/src/test/mir-opt/const_prop/discriminant.rs b/src/test/mir-opt/const_prop/discriminant.rs new file mode 100644 index 0000000000000..07bbd9202b940 --- /dev/null +++ b/src/test/mir-opt/const_prop/discriminant.rs @@ -0,0 +1,53 @@ +// compile-flags: -O + +fn main() { + let x = (if let Some(true) = Some(true) { 42 } else { 10 }) + 0; +} + +// END RUST SOURCE +// START rustc.main.ConstProp.before.mir +// bb0: { +// ... +// _3 = std::option::Option::::Some(const true,); +// _4 = discriminant(_3); +// switchInt(move _4) -> [1isize: bb3, otherwise: bb2]; +// } +// bb1: { +// _2 = const 42i32; +// goto -> bb4; +// } +// bb2: { +// _2 = const 10i32; +// goto -> bb4; +// } +// bb3: { +// switchInt(((_3 as Some).0: bool)) -> [false: bb2, otherwise: bb1]; +// } +// bb4: { +// _1 = Add(move _2, const 0i32); +// ... +// } +// END rustc.main.ConstProp.before.mir +// START rustc.main.ConstProp.after.mir +// bb0: { +// ... +// _3 = const Scalar(0x01) : std::option::Option; +// _4 = const 1isize; +// switchInt(const 1isize) -> [1isize: bb3, otherwise: bb2]; +// } +// bb1: { +// _2 = const 42i32; +// goto -> bb4; +// } +// bb2: { +// _2 = const 10i32; +// goto -> bb4; +// } +// bb3: { +// switchInt(const true) -> [false: bb2, otherwise: bb1]; +// } +// bb4: { +// _1 = Add(move _2, const 0i32); +// ... +// } +// END rustc.main.ConstProp.after.mir diff --git a/src/test/mir-opt/const_prop/repeat.rs b/src/test/mir-opt/const_prop/repeat.rs new file mode 100644 index 0000000000000..fb091ad2a3d53 --- /dev/null +++ b/src/test/mir-opt/const_prop/repeat.rs @@ -0,0 +1,37 @@ +// compile-flags: -O + +fn main() { + let x: u32 = [42; 8][2] + 0; +} + +// END RUST SOURCE +// START rustc.main.ConstProp.before.mir +// bb0: { +// ... +// _3 = [const 42u32; 8]; +// ... +// _4 = const 2usize; +// _5 = const 8usize; +// _6 = Lt(_4, _5); +// assert(move _6, "index out of bounds: the len is move _5 but the index is _4") -> bb1; +// } +// bb1: { +// _2 = _3[_4]; +// _1 = Add(move _2, const 0u32); +// ... +// return; +// } +// END rustc.main.ConstProp.before.mir +// START rustc.main.ConstProp.after.mir +// bb0: { +// ... +// _6 = const true; +// assert(const true, "index out of bounds: the len is move _5 but the index is _4") -> bb1; +// } +// bb1: { +// _2 = const 42u32; +// _1 = Add(move _2, const 0u32); +// ... +// return; +// } +// END rustc.main.ConstProp.after.mir diff --git a/src/test/run-fail/overflowing-rsh-5.rs b/src/test/run-fail/overflowing-rsh-5.rs index 793f495240d57..58dfc5710ae4e 100644 --- a/src/test/run-fail/overflowing-rsh-5.rs +++ b/src/test/run-fail/overflowing-rsh-5.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { let _n = 1i64 >> [64][0]; diff --git a/src/test/run-fail/overflowing-rsh-6.rs b/src/test/run-fail/overflowing-rsh-6.rs index d6b2f8dc9f9af..c2fec5e4860af 100644 --- a/src/test/run-fail/overflowing-rsh-6.rs +++ b/src/test/run-fail/overflowing-rsh-6.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] #![feature(const_indexing)] fn main() { diff --git a/src/test/ui/consts/const-err2.rs b/src/test/ui/consts/const-err2.rs index ecbcc2a4b496f..e5ee90fc9f11f 100644 --- a/src/test/ui/consts/const-err2.rs +++ b/src/test/ui/consts/const-err2.rs @@ -23,6 +23,7 @@ fn main() { //~^ ERROR const_err let _e = [5u8][1]; //~^ ERROR index out of bounds + //~| ERROR this expression will panic at runtime black_box(a); black_box(b); black_box(c); diff --git a/src/test/ui/consts/const-err2.stderr b/src/test/ui/consts/const-err2.stderr index 1d84d44dc27b3..0a09a7213dabc 100644 --- a/src/test/ui/consts/const-err2.stderr +++ b/src/test/ui/consts/const-err2.stderr @@ -34,5 +34,11 @@ error: index out of bounds: the len is 1 but the index is 1 LL | let _e = [5u8][1]; | ^^^^^^^^ -error: aborting due to 5 previous errors +error: this expression will panic at runtime + --> $DIR/const-err2.rs:24:14 + | +LL | let _e = [5u8][1]; + | ^^^^^^^^ index out of bounds: the len is 1 but the index is 1 + +error: aborting due to 6 previous errors diff --git a/src/test/ui/consts/const-err3.rs b/src/test/ui/consts/const-err3.rs index a9cf04cda7a5a..89373f99f75c2 100644 --- a/src/test/ui/consts/const-err3.rs +++ b/src/test/ui/consts/const-err3.rs @@ -23,6 +23,7 @@ fn main() { //~^ ERROR const_err let _e = [5u8][1]; //~^ ERROR const_err + //~| ERROR this expression will panic at runtime black_box(a); black_box(b); black_box(c); diff --git a/src/test/ui/consts/const-err3.stderr b/src/test/ui/consts/const-err3.stderr index 0602707be7040..42de247c8f7e0 100644 --- a/src/test/ui/consts/const-err3.stderr +++ b/src/test/ui/consts/const-err3.stderr @@ -34,5 +34,11 @@ error: index out of bounds: the len is 1 but the index is 1 LL | let _e = [5u8][1]; | ^^^^^^^^ -error: aborting due to 5 previous errors +error: this expression will panic at runtime + --> $DIR/const-err3.rs:24:14 + | +LL | let _e = [5u8][1]; + | ^^^^^^^^ index out of bounds: the len is 1 but the index is 1 + +error: aborting due to 6 previous errors diff --git a/src/test/ui/consts/const-prop-ice.rs b/src/test/ui/consts/const-prop-ice.rs index 13309f978b672..48c4b7da942e4 100644 --- a/src/test/ui/consts/const-prop-ice.rs +++ b/src/test/ui/consts/const-prop-ice.rs @@ -1,3 +1,4 @@ fn main() { [0; 3][3u64 as usize]; //~ ERROR the len is 3 but the index is 3 + //~| ERROR this expression will panic at runtime } diff --git a/src/test/ui/consts/const-prop-ice.stderr b/src/test/ui/consts/const-prop-ice.stderr index 4b3880198bf2d..8ecc6f4bc6b12 100644 --- a/src/test/ui/consts/const-prop-ice.stderr +++ b/src/test/ui/consts/const-prop-ice.stderr @@ -6,5 +6,11 @@ LL | [0; 3][3u64 as usize]; | = note: `#[deny(const_err)]` on by default -error: aborting due to previous error +error: this expression will panic at runtime + --> $DIR/const-prop-ice.rs:2:5 + | +LL | [0; 3][3u64 as usize]; + | ^^^^^^^^^^^^^^^^^^^^^ index out of bounds: the len is 3 but the index is 3 + +error: aborting due to 2 previous errors diff --git a/src/test/ui/issues/issue-54348.rs b/src/test/ui/issues/issue-54348.rs index 68d838054776e..e7221e2cbb1e1 100644 --- a/src/test/ui/issues/issue-54348.rs +++ b/src/test/ui/issues/issue-54348.rs @@ -1,5 +1,7 @@ fn main() { [1][0u64 as usize]; [1][1.5 as usize]; //~ ERROR index out of bounds + //~| ERROR this expression will panic at runtime [1][1u64 as usize]; //~ ERROR index out of bounds + //~| ERROR this expression will panic at runtime } diff --git a/src/test/ui/issues/issue-54348.stderr b/src/test/ui/issues/issue-54348.stderr index fa77bd6fd7797..79320ef4f31c7 100644 --- a/src/test/ui/issues/issue-54348.stderr +++ b/src/test/ui/issues/issue-54348.stderr @@ -6,11 +6,23 @@ LL | [1][1.5 as usize]; | = note: `#[deny(const_err)]` on by default +error: this expression will panic at runtime + --> $DIR/issue-54348.rs:3:5 + | +LL | [1][1.5 as usize]; + | ^^^^^^^^^^^^^^^^^ index out of bounds: the len is 1 but the index is 1 + error: index out of bounds: the len is 1 but the index is 1 - --> $DIR/issue-54348.rs:4:5 + --> $DIR/issue-54348.rs:5:5 | LL | [1][1u64 as usize]; | ^^^^^^^^^^^^^^^^^^ -error: aborting due to 2 previous errors +error: this expression will panic at runtime + --> $DIR/issue-54348.rs:5:5 + | +LL | [1][1u64 as usize]; + | ^^^^^^^^^^^^^^^^^^ index out of bounds: the len is 1 but the index is 1 + +error: aborting due to 4 previous errors diff --git a/src/test/ui/lint/lint-exceeding-bitshifts2.rs b/src/test/ui/lint/lint-exceeding-bitshifts2.rs index 69b627355b801..2c213daddd752 100644 --- a/src/test/ui/lint/lint-exceeding-bitshifts2.rs +++ b/src/test/ui/lint/lint-exceeding-bitshifts2.rs @@ -8,7 +8,7 @@ fn main() { let n = 1u8 << (4+3); let n = 1u8 << (4+4); //~ ERROR: attempt to shift left with overflow let n = 1i64 >> [63][0]; - let n = 1i64 >> [64][0]; // should be linting, needs to wait for const propagation + let n = 1i64 >> [64][0]; //~ ERROR: attempt to shift right with overflow #[cfg(target_pointer_width = "32")] const BITS: usize = 32; diff --git a/src/test/ui/lint/lint-exceeding-bitshifts2.stderr b/src/test/ui/lint/lint-exceeding-bitshifts2.stderr index cb96982a78930..d9c76d233d03e 100644 --- a/src/test/ui/lint/lint-exceeding-bitshifts2.stderr +++ b/src/test/ui/lint/lint-exceeding-bitshifts2.stderr @@ -10,6 +10,12 @@ note: lint level defined here LL | #![deny(exceeding_bitshifts, const_err)] | ^^^^^^^^^^^^^^^^^^^ +error: attempt to shift right with overflow + --> $DIR/lint-exceeding-bitshifts2.rs:11:15 + | +LL | let n = 1i64 >> [64][0]; + | ^^^^^^^^^^^^^^^ + error: attempt to shift left with overflow --> $DIR/lint-exceeding-bitshifts2.rs:17:15 | @@ -22,5 +28,5 @@ error: attempt to shift left with overflow LL | let n = 1_usize << BITS; | ^^^^^^^^^^^^^^^ -error: aborting due to 3 previous errors +error: aborting due to 4 previous errors