diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs index 3376af98653..149e4c2cb08 100644 --- a/compiler/rustc_monomorphize/src/collector.rs +++ b/compiler/rustc_monomorphize/src/collector.rs @@ -666,7 +666,15 @@ impl<'a, 'tcx> MirUsedCollector<'a, 'tcx> { debug!(?def_id, ?fn_span); for arg in args { - if let Some(too_large_size) = self.operand_size_if_too_large(limit, &arg.node) { + // Moving args into functions is typically implemented with pointer + // passing at the llvm-ir level and not by memcpy's. So always allow + // moving args into functions. + let operand: &mir::Operand<'tcx> = &arg.node; + if let mir::Operand::Move(_) = operand { + continue; + } + + if let Some(too_large_size) = self.operand_size_if_too_large(limit, operand) { self.lint_large_assignment(limit.0, too_large_size, location, arg.span); }; } diff --git a/tests/ui/lint/large_assignments/box_rc_arc_allowed.rs b/tests/ui/lint/large_assignments/box_rc_arc_allowed.rs deleted file mode 100644 index 33113642023..00000000000 --- a/tests/ui/lint/large_assignments/box_rc_arc_allowed.rs +++ /dev/null @@ -1,29 +0,0 @@ -#![deny(large_assignments)] -#![feature(large_assignments)] -#![move_size_limit = "1000"] -// build-fail -// only-x86_64 - -// edition:2018 -// compile-flags: -Zmir-opt-level=0 - -use std::{sync::Arc, rc::Rc}; - -fn main() { - let _ = Arc::new([0; 9999]); // OK! - let _ = Box::new([0; 9999]); // OK! - let _ = Rc::new([0; 9999]); // OK! - let _ = NotBox::new([0; 9999]); //~ ERROR large_assignments -} - -struct NotBox { - data: [u8; 9999], -} - -impl NotBox { - fn new(data: [u8; 9999]) -> Self { - Self { - data, //~ ERROR large_assignments - } - } -} diff --git a/tests/ui/lint/large_assignments/copy_into_box_rc_arc.rs b/tests/ui/lint/large_assignments/copy_into_box_rc_arc.rs new file mode 100644 index 00000000000..866a4d10ff5 --- /dev/null +++ b/tests/ui/lint/large_assignments/copy_into_box_rc_arc.rs @@ -0,0 +1,38 @@ +#![deny(large_assignments)] +#![feature(large_assignments)] +#![move_size_limit = "1000"] +// build-fail +// only-64bit + +// edition:2018 +// compile-flags: -Zmir-opt-level=1 + +use std::{sync::Arc, rc::Rc}; + +fn main() { + let data = [0; 9999]; + + // Looking at --emit mir, we can see that all parameters below are passed by + // copy. But it requires at least mir-opt-level=1. + let _ = Arc::new(data); // OK! + let _ = Box::new(data); // OK! + let _ = Rc::new(data); // OK! + + // Looking at --emit llvm-ir, we can see that a memcpy is involved in the + // parameter passing. So we want the lint to trigger here. + let _ = NotBox::new(data); //~ ERROR large_assignments +} + +struct NotBox { + data: [u8; 9999], +} + +impl NotBox { + fn new(data: [u8; 9999]) -> Self { + // Looking at --emit llvm-ir, we can see that a memcpy is involved. + // So we want the lint to trigger here. + Self { //~ ERROR large_assignments + data, + } + } +} diff --git a/tests/ui/lint/large_assignments/box_rc_arc_allowed.stderr b/tests/ui/lint/large_assignments/copy_into_box_rc_arc.stderr similarity index 60% rename from tests/ui/lint/large_assignments/box_rc_arc_allowed.stderr rename to tests/ui/lint/large_assignments/copy_into_box_rc_arc.stderr index fefb3a9621b..6e42328a111 100644 --- a/tests/ui/lint/large_assignments/box_rc_arc_allowed.stderr +++ b/tests/ui/lint/large_assignments/copy_into_box_rc_arc.stderr @@ -1,21 +1,23 @@ error: moving 9999 bytes - --> $DIR/box_rc_arc_allowed.rs:16:25 + --> $DIR/copy_into_box_rc_arc.rs:23:25 | -LL | let _ = NotBox::new([0; 9999]); - | ^^^^^^^^^ value moved from here +LL | let _ = NotBox::new(data); + | ^^^^ value moved from here | = note: The current maximum size is 1000, but it can be customized with the move_size_limit attribute: `#![move_size_limit = "..."]` note: the lint level is defined here - --> $DIR/box_rc_arc_allowed.rs:1:9 + --> $DIR/copy_into_box_rc_arc.rs:1:9 | LL | #![deny(large_assignments)] | ^^^^^^^^^^^^^^^^^ error: moving 9999 bytes - --> $DIR/box_rc_arc_allowed.rs:26:13 + --> $DIR/copy_into_box_rc_arc.rs:34:9 | -LL | data, - | ^^^^ value moved from here +LL | / Self { +LL | | data, +LL | | } + | |_________^ value moved from here | = note: The current maximum size is 1000, but it can be customized with the move_size_limit attribute: `#![move_size_limit = "..."]` diff --git a/tests/ui/lint/large_assignments/large_future.rs b/tests/ui/lint/large_assignments/large_future.rs index 834746fa97e..a69ff356c6b 100644 --- a/tests/ui/lint/large_assignments/large_future.rs +++ b/tests/ui/lint/large_assignments/large_future.rs @@ -2,7 +2,7 @@ #![cfg_attr(attribute, feature(large_assignments))] #![cfg_attr(attribute, move_size_limit = "1000")] // build-fail -// only-x86_64 +// only-64bit // revisions: attribute option // [option]compile-flags: -Zmove-size-limit=1000 diff --git a/tests/ui/lint/large_assignments/move_into_box_rc_arc.rs b/tests/ui/lint/large_assignments/move_into_box_rc_arc.rs new file mode 100644 index 00000000000..b7a70dfdda0 --- /dev/null +++ b/tests/ui/lint/large_assignments/move_into_box_rc_arc.rs @@ -0,0 +1,38 @@ +#![deny(large_assignments)] +#![feature(large_assignments)] +#![move_size_limit = "1000"] +// build-fail +// only-64bit + +// edition:2018 +// compile-flags: -Zmir-opt-level=0 + +use std::{sync::Arc, rc::Rc}; + +fn main() { + // Looking at --emit mir, we can see that all parameters below are passed + // by move. + let _ = Arc::new([0; 9999]); // OK! + let _ = Box::new([0; 9999]); // OK! + let _ = Rc::new([0; 9999]); // OK! + + // Looking at --emit llvm-ir, we can see that no memcpy is involved in the + // parameter passing. Instead, a pointer is passed. This is typically what + // we get when moving parameter into functions. So we don't want the lint to + // trigger here. + let _ = NotBox::new([0; 9999]); // OK (compare with copy_into_box_rc_arc.rs) +} + +struct NotBox { + data: [u8; 9999], +} + +impl NotBox { + fn new(data: [u8; 9999]) -> Self { + Self { + // Looking at --emit llvm-ir, we can see that a memcpy is involved. + // So we want the lint to trigger here. + data, //~ ERROR large_assignments + } + } +} diff --git a/tests/ui/lint/large_assignments/move_into_box_rc_arc.stderr b/tests/ui/lint/large_assignments/move_into_box_rc_arc.stderr new file mode 100644 index 00000000000..a386de5e5e8 --- /dev/null +++ b/tests/ui/lint/large_assignments/move_into_box_rc_arc.stderr @@ -0,0 +1,15 @@ +error: moving 9999 bytes + --> $DIR/move_into_box_rc_arc.rs:35:13 + | +LL | data, + | ^^^^ value moved from here + | + = note: The current maximum size is 1000, but it can be customized with the move_size_limit attribute: `#![move_size_limit = "..."]` +note: the lint level is defined here + --> $DIR/move_into_box_rc_arc.rs:1:9 + | +LL | #![deny(large_assignments)] + | ^^^^^^^^^^^^^^^^^ + +error: aborting due to 1 previous error + diff --git a/tests/ui/lint/large_assignments/move_into_fn.rs b/tests/ui/lint/large_assignments/move_into_fn.rs new file mode 100644 index 00000000000..359705bfc03 --- /dev/null +++ b/tests/ui/lint/large_assignments/move_into_fn.rs @@ -0,0 +1,22 @@ +// build-fail + +#![feature(large_assignments)] +#![move_size_limit = "1000"] +#![deny(large_assignments)] +#![allow(unused)] + +// Note: This type does not implement Copy. +struct Data([u8; 9999]); + +fn main() { + // Looking at llvm-ir output, we can see a memcpy'd into Data, so we want + // the lint to trigger here. + let data = Data([100; 9999]); //~ ERROR large_assignments + + // Looking at llvm-ir output, we can see that there is no memcpy involved in + // this function call. Instead, just a pointer is passed to the function. So + // the lint shall not trigger here. + take_data(data); +} + +fn take_data(data: Data) {} diff --git a/tests/ui/lint/large_assignments/move_into_fn.stderr b/tests/ui/lint/large_assignments/move_into_fn.stderr new file mode 100644 index 00000000000..92a0489e472 --- /dev/null +++ b/tests/ui/lint/large_assignments/move_into_fn.stderr @@ -0,0 +1,15 @@ +error: moving 9999 bytes + --> $DIR/move_into_fn.rs:14:16 + | +LL | let data = Data([100; 9999]); + | ^^^^^^^^^^^^^^^^^ value moved from here + | + = note: The current maximum size is 1000, but it can be customized with the move_size_limit attribute: `#![move_size_limit = "..."]` +note: the lint level is defined here + --> $DIR/move_into_fn.rs:5:9 + | +LL | #![deny(large_assignments)] + | ^^^^^^^^^^^^^^^^^ + +error: aborting due to 1 previous error +