diff --git a/compiler/rustc_codegen_gcc/src/builder.rs b/compiler/rustc_codegen_gcc/src/builder.rs
index be3f6a12706f8..aa7ffb97444ca 100644
--- a/compiler/rustc_codegen_gcc/src/builder.rs
+++ b/compiler/rustc_codegen_gcc/src/builder.rs
@@ -1403,7 +1403,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
self.cx
}
- fn do_not_inline(&mut self, _llret: RValue<'gcc>) {
+ fn apply_attrs_to_cleanup_callsite(&mut self, _llret: RValue<'gcc>) {
unimplemented!();
}
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index c4eb593d2976a..097180b3bd599 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -23,6 +23,7 @@ use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_span::Span;
use rustc_target::abi::{self, call::FnAbi, Align, Size, WrappingRange};
use rustc_target::spec::{HasTargetSpec, Target};
+use smallvec::SmallVec;
use std::borrow::Cow;
use std::ffi::CStr;
use std::iter;
@@ -1188,9 +1189,19 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
unsafe { llvm::LLVMBuildZExt(self.llbuilder, val, dest_ty, UNNAMED) }
}
- fn do_not_inline(&mut self, llret: &'ll Value) {
- let noinline = llvm::AttributeKind::NoInline.create_attr(self.llcx);
- attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &[noinline]);
+ fn apply_attrs_to_cleanup_callsite(&mut self, llret: &'ll Value) {
+ let mut attrs = SmallVec::<[_; 2]>::new();
+
+ // Cleanup is always the cold path.
+ attrs.push(llvm::AttributeKind::Cold.create_attr(self.llcx));
+
+ // LLVM 14 contains fixes for catastrophic inlining behavior, without which
+ // inlining drop glue can lead to exponential size blowup, see #41696 and #92110.
+ if llvm_util::get_version() < (14, 0, 0) {
+ attrs.push(llvm::AttributeKind::NoInline.create_attr(self.llcx));
+ }
+
+ attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &attrs);
}
}
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index a87daa8d6b80b..f6c41af41b4d3 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -166,7 +166,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
bx.invoke(fn_ty, fn_ptr, &llargs, ret_llbb, unwind_block, self.funclet(fx));
bx.apply_attrs_callsite(&fn_abi, invokeret);
if fx.mir[self.bb].is_cleanup {
- bx.do_not_inline(invokeret);
+ bx.apply_attrs_to_cleanup_callsite(invokeret);
}
if let Some((ret_dest, target)) = destination {
@@ -178,11 +178,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
let llret = bx.call(fn_ty, fn_ptr, &llargs, self.funclet(fx));
bx.apply_attrs_callsite(&fn_abi, llret);
if fx.mir[self.bb].is_cleanup {
- // Cleanup is always the cold path. Don't inline
- // drop glue. Also, when there is a deeply-nested
- // struct, there are "symmetry" issues that cause
- // exponential inlining - see issue #41696.
- bx.do_not_inline(llret);
+ bx.apply_attrs_to_cleanup_callsite(llret);
}
if let Some((ret_dest, target)) = destination {
@@ -1448,7 +1444,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let llret = bx.call(fn_ty, fn_ptr, &[], None);
bx.apply_attrs_callsite(&fn_abi, llret);
- bx.do_not_inline(llret);
+ bx.apply_attrs_to_cleanup_callsite(llret);
bx.unreachable();
diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs
index 37f2bfd3c4fbd..1c7fe060ea4fb 100644
--- a/compiler/rustc_codegen_ssa/src/traits/builder.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs
@@ -479,5 +479,5 @@ pub trait BuilderMethods<'a, 'tcx>:
) -> Self::Value;
fn zext(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value;
- fn do_not_inline(&mut self, llret: Self::Value);
+ fn apply_attrs_to_cleanup_callsite(&mut self, llret: Self::Value);
}
diff --git a/src/test/codegen/unwind-landingpad-cold.rs b/src/test/codegen/unwind-landingpad-cold.rs
new file mode 100644
index 0000000000000..aa00b7936541e
--- /dev/null
+++ b/src/test/codegen/unwind-landingpad-cold.rs
@@ -0,0 +1,15 @@
+// no-system-llvm: needs #92110
+// compile-flags: -Cno-prepopulate-passes
+#![crate_type = "lib"]
+
+// This test checks that drop calls in unwind landing pads
+// get the `cold` attribute.
+
+// CHECK-LABEL: @check_cold
+// CHECK: {{(call|invoke) void .+}}drop_in_place{{.+}} [[ATTRIBUTES:#[0-9]+]]
+// CHECK: attributes [[ATTRIBUTES]] = { cold }
+#[no_mangle]
+pub fn check_cold(f: fn(), x: Box<u32>) {
+ // this may unwind
+ f();
+}
diff --git a/src/test/codegen/unwind-landingpad-inline.rs b/src/test/codegen/unwind-landingpad-inline.rs
new file mode 100644
index 0000000000000..ce78d075dd0f4
--- /dev/null
+++ b/src/test/codegen/unwind-landingpad-inline.rs
@@ -0,0 +1,37 @@
+// no-system-llvm: needs #92110 + patch for Rust alloc/dealloc functions
+// compile-flags: -Copt-level=3
+#![crate_type = "lib"]
+
+// This test checks that we can inline drop_in_place in
+// unwind landing pads.
+
+// Without inlining, the box pointers escape via the call to drop_in_place,
+// and LLVM will not optimize out the pointer comparison.
+// With inlining, everything should be optimized out.
+// See https://github.com/rust-lang/rust/issues/46515
+// CHECK-LABEL: @check_no_escape_in_landingpad
+// CHECK: start:
+// CHECK-NEXT: ret void
+#[no_mangle]
+pub fn check_no_escape_in_landingpad(f: fn()) {
+ let x = &*Box::new(0);
+ let y = &*Box::new(0);
+
+ if x as *const _ == y as *const _ {
+ f();
+ }
+}
+
+// Without inlining, the compiler can't tell that
+// dropping an empty string (in a landing pad) does nothing.
+// With inlining, the landing pad should be optimized out.
+// See https://github.com/rust-lang/rust/issues/87055
+// CHECK-LABEL: @check_eliminate_noop_drop
+// CHECK: start:
+// CHECK-NEXT: call void %g()
+// CHECK-NEXT: ret void
+#[no_mangle]
+pub fn check_eliminate_noop_drop(g: fn()) {
+ let _var = String::new();
+ g();
+}
diff --git a/src/test/codegen/vec-shrink-panik.rs b/src/test/codegen/vec-shrink-panik.rs
index 18409014bdede..6b0ac78857a0e 100644
--- a/src/test/codegen/vec-shrink-panik.rs
+++ b/src/test/codegen/vec-shrink-panik.rs
@@ -16,14 +16,6 @@ pub fn shrink_to_fit(vec: &mut Vec<u32>) {
// CHECK-LABEL: @issue71861
#[no_mangle]
pub fn issue71861(vec: Vec<u32>) -> Box<[u32]> {
- // CHECK-NOT: panic
-
- // Call to panic_no_unwind in case of double-panic is expected,
- // but other panics are not.
- // CHECK: cleanup
- // CHECK-NEXT: ; call core::panicking::panic_no_unwind
- // CHECK-NEXT: panic_no_unwind
-
// CHECK-NOT: panic
vec.into_boxed_slice()
}
@@ -31,17 +23,6 @@ pub fn issue71861(vec: Vec<u32>) -> Box<[u32]> {
// CHECK-LABEL: @issue75636
#[no_mangle]
pub fn issue75636<'a>(iter: &[&'a str]) -> Box<[&'a str]> {
- // CHECK-NOT: panic
-
- // Call to panic_no_unwind in case of double-panic is expected,
- // but other panics are not.
- // CHECK: cleanup
- // CHECK-NEXT: ; call core::panicking::panic_no_unwind
- // CHECK-NEXT: panic_no_unwind
-
// CHECK-NOT: panic
iter.iter().copied().collect()
}
-
-// CHECK: ; core::panicking::panic_no_unwind
-// CHECK: declare void @{{.*}}panic_no_unwind