From b0c80a93e41548bf706dc886b8875952f6456b0c Mon Sep 17 00:00:00 2001
From: Ariel Ben-Yehuda <ariel.byd@gmail.com>
Date: Thu, 11 May 2017 23:09:31 +0300
Subject: [PATCH] remove the #[inline] attribute from drop_in_place

Apparently LLVM has exponential code growth while inlining landing pads
if that attribute is present.

Fixes #41696.
---
 src/libcore/ptr.rs               |  1 -
 src/librustc_trans/common.rs     |  6 ++++
 src/test/run-pass/issue-41696.rs | 60 ++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 src/test/run-pass/issue-41696.rs

diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index a60abefc07650..0944e74f6f18a 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -56,7 +56,6 @@ pub use intrinsics::write_bytes;
 /// invalid pointers, types, and double drops.
 #[stable(feature = "drop_in_place", since = "1.8.0")]
 #[lang="drop_in_place"]
-#[inline]
 #[allow(unconditional_recursion)]
 pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
     // Code here does not matter - this is replaced by the
diff --git a/src/librustc_trans/common.rs b/src/librustc_trans/common.rs
index 025062f7ddef9..efd4f13678502 100644
--- a/src/librustc_trans/common.rs
+++ b/src/librustc_trans/common.rs
@@ -537,6 +537,12 @@ pub fn requests_inline<'a, 'tcx>(
     if is_inline_instance(tcx, instance) {
         return true
     }
+    if let ty::InstanceDef::DropGlue(..) = instance.def {
+        // Drop glue wants to be instantiated at every translation
+        // unit, but without an #[inline] hint. We should make this
+        // available to normal end-users.
+        return true
+    }
     attr::requests_inline(&instance.def.attrs(tcx)[..])
 }
 
diff --git a/src/test/run-pass/issue-41696.rs b/src/test/run-pass/issue-41696.rs
new file mode 100644
index 0000000000000..1888be58c57d0
--- /dev/null
+++ b/src/test/run-pass/issue-41696.rs
@@ -0,0 +1,60 @@
+// Copyright 2017 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.
+
+// this used to cause exponential code-size blowup during LLVM passes.
+
+#![feature(test)]
+
+extern crate test;
+
+struct MayUnwind;
+
+impl Drop for MayUnwind {
+    fn drop(&mut self) {
+        if test::black_box(false) {
+            panic!()
+        }
+    }
+}
+
+struct DS<U> {
+    may_unwind: MayUnwind,
+    name: String,
+    next: U,
+}
+
+fn add<U>(ds: DS<U>, name: String) -> DS<DS<U>> {
+    DS {
+        may_unwind: MayUnwind,
+        name: "?".to_owned(),
+        next: ds,
+    }
+}
+
+fn main() {
+    let deserializers = DS { may_unwind: MayUnwind, name: "?".to_owned(), next: () };
+    let deserializers = add(deserializers, "?".to_owned());
+    let deserializers = add(deserializers, "?".to_owned());
+    let deserializers = add(deserializers, "?".to_owned());
+    let deserializers = add(deserializers, "?".to_owned());
+    let deserializers = add(deserializers, "?".to_owned());
+    let deserializers = add(deserializers, "?".to_owned());
+    let deserializers = add(deserializers, "?".to_owned()); // 0.7s
+    let deserializers = add(deserializers, "?".to_owned()); // 1.3s
+    let deserializers = add(deserializers, "?".to_owned()); // 2.4s
+    let deserializers = add(deserializers, "?".to_owned()); // 6.7s
+    let deserializers = add(deserializers, "?".to_owned()); // 26.0s
+    let deserializers = add(deserializers, "?".to_owned()); // 114.0s
+    let deserializers = add(deserializers, "?".to_owned()); // 228.0s
+    let deserializers = add(deserializers, "?".to_owned()); // 400.0s
+    let deserializers = add(deserializers, "?".to_owned()); // 800.0s
+    let deserializers = add(deserializers, "?".to_owned()); // 1600.0s
+    let deserializers = add(deserializers, "?".to_owned()); // 3200.0s
+}