Convert codegen-unit tests to use `start` instead of `main`

The new Termination traits brings in the unwinding machinery and that
blows up the required `TRANS_ITEM`s.

24 files changed, 148 insertions, 454 deletions

diff --git a/src/test/codegen-units/item-collection/cross-crate-closures.rs b/src/test/codegen-units/item-collection/cross-crate-closures.rs
index 2b5ac7e8d80..320be278198 100644
--- a/src/test/codegen-units/item-collection/cross-crate-closures.rs
+++ b/src/test/codegen-units/item-collection/cross-crate-closures.rs
@@ -17,12 +17,14 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 // aux-build:cgu_extern_closures.rs
 extern crate cgu_extern_closures;
 
-//~ TRANS_ITEM fn cross_crate_closures::main[0]
-fn main() {
+//~ TRANS_ITEM fn cross_crate_closures::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
 
     //~ TRANS_ITEM fn cgu_extern_closures::inlined_fn[0]
     //~ TRANS_ITEM fn cgu_extern_closures::inlined_fn[0]::{{closure}}[0]
@@ -35,6 +37,8 @@ fn main() {
     // Nothing should be generated for this call, we just link to the instance
     // in the extern crate.
     let _ = cgu_extern_closures::non_inlined_fn(6, 7);
+
+    0
 }
 
 //~ TRANS_ITEM drop-glue i8
diff --git a/src/test/codegen-units/item-collection/cross-crate-generic-functions.rs b/src/test/codegen-units/item-collection/cross-crate-generic-functions.rs
index 411f3da9182..bcb3b7b1dad 100644
--- a/src/test/codegen-units/item-collection/cross-crate-generic-functions.rs
+++ b/src/test/codegen-units/item-collection/cross-crate-generic-functions.rs
@@ -12,32 +12,14 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 // aux-build:cgu_generic_function.rs
 extern crate cgu_generic_function;
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ cross_crate_generic_functions0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ cross_crate_generic_functions0[Internal]
-//~ TRANS_ITEM fn cross_crate_generic_functions::main[0]
-fn main()
-{
+//~ TRANS_ITEM fn cross_crate_generic_functions::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn cgu_generic_function::bar[0]<u32>
     //~ TRANS_ITEM fn cgu_generic_function::foo[0]<u32>
     let _ = cgu_generic_function::foo(1u32);
@@ -48,4 +30,6 @@ fn main()
 
     // This should not introduce a codegen item
     let _ = cgu_generic_function::exported_but_not_generic(3);
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/cross-crate-trait-method.rs b/src/test/codegen-units/item-collection/cross-crate-trait-method.rs
index a269b6da230..910ae000848 100644
--- a/src/test/codegen-units/item-collection/cross-crate-trait-method.rs
+++ b/src/test/codegen-units/item-collection/cross-crate-trait-method.rs
@@ -12,34 +12,16 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 // aux-build:cgu_export_trait_method.rs
 extern crate cgu_export_trait_method;
 
 use cgu_export_trait_method::Trait;
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ cross_crate_trait_method0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ cross_crate_trait_method0[Internal]
-//~ TRANS_ITEM fn cross_crate_trait_method::main[0]
-fn main()
-{
+//~ TRANS_ITEM fn cross_crate_trait_method::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     // The object code of these methods is contained in the external crate, so
     // calling them should *not* introduce codegen items in the current crate.
     let _: (u32, u32) = Trait::without_default_impl(0);
@@ -74,4 +56,6 @@ fn main()
     let _: (char, char) = Trait::without_default_impl_generic('c');
     //~ TRANS_ITEM fn cgu_export_trait_method::{{impl}}[0]::without_default_impl_generic[0]<bool>
     let _: (char, bool) = Trait::without_default_impl_generic(false);
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/drop_in_place_intrinsic.rs b/src/test/codegen-units/item-collection/drop_in_place_intrinsic.rs
index 88888afa693..52af8165032 100644
--- a/src/test/codegen-units/item-collection/drop_in_place_intrinsic.rs
+++ b/src/test/codegen-units/item-collection/drop_in_place_intrinsic.rs
@@ -12,6 +12,8 @@
 // compile-flags:-Zprint-trans-items=eager
 // compile-flags:-Zinline-in-all-cgus
 
+#![feature(start)]
+
 //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<drop_in_place_intrinsic::StructWithDtor[0]> @@ drop_in_place_intrinsic0[Internal]
 struct StructWithDtor(u32);
 
@@ -20,32 +22,16 @@ impl Drop for StructWithDtor {
     fn drop(&mut self) {}
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ drop_in_place_intrinsic0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ drop_in_place_intrinsic0[Internal]
-//~ TRANS_ITEM fn drop_in_place_intrinsic::main[0]
-fn main() {
+//~ TRANS_ITEM fn drop_in_place_intrinsic::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
 
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<[drop_in_place_intrinsic::StructWithDtor[0]; 2]> @@ drop_in_place_intrinsic0[Internal]
     let x = [StructWithDtor(0), StructWithDtor(1)];
 
     drop_slice_in_place(&x);
+
+    0
 }
 
 //~ TRANS_ITEM fn drop_in_place_intrinsic::drop_slice_in_place[0]
diff --git a/src/test/codegen-units/item-collection/function-as-argument.rs b/src/test/codegen-units/item-collection/function-as-argument.rs
index 3fb25d9b2a0..65707c1aa4d 100644
--- a/src/test/codegen-units/item-collection/function-as-argument.rs
+++ b/src/test/codegen-units/item-collection/function-as-argument.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 fn take_fn_once<T1, T2, F: FnOnce(T1, T2)>(f: F, x: T1, y: T2) {
     (f)(x, y)
@@ -23,27 +24,9 @@ fn take_fn_pointer<T1, T2>(f: fn(T1, T2), x: T1, y: T2) {
     (f)(x, y)
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ function_as_argument0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ function_as_argument0[Internal]
-//~ TRANS_ITEM fn function_as_argument::main[0]
-fn main() {
+//~ TRANS_ITEM fn function_as_argument::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
 
     //~ TRANS_ITEM fn function_as_argument::take_fn_once[0]<u32, &str, fn(u32, &str)>
     //~ TRANS_ITEM fn function_as_argument::function[0]<u32, &str>
@@ -62,4 +45,6 @@ fn main() {
     //~ TRANS_ITEM fn function_as_argument::take_fn_pointer[0]<f32, i64>
     //~ TRANS_ITEM fn function_as_argument::function[0]<f32, i64>
     take_fn_pointer(function, 0f32, 0i64);
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/generic-drop-glue.rs b/src/test/codegen-units/item-collection/generic-drop-glue.rs
index 0d08611d1cc..d3d9aa3aefc 100644
--- a/src/test/codegen-units/item-collection/generic-drop-glue.rs
+++ b/src/test/codegen-units/item-collection/generic-drop-glue.rs
@@ -13,6 +13,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![deny(dead_code)]
+#![feature(start)]
 
 struct StructWithDrop<T1, T2> {
     x: T1,
@@ -53,27 +54,9 @@ impl Drop for NonGenericWithDrop {
     fn drop(&mut self) {}
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ generic_drop_glue0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn generic_drop_glue::main[0]
-fn main() {
+//~ TRANS_ITEM fn generic_drop_glue::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<generic_drop_glue::StructWithDrop[0]<i8, char>> @@ generic_drop_glue0[Internal]
     //~ TRANS_ITEM fn generic_drop_glue::{{impl}}[0]::drop[0]<i8, char>
     let _ = StructWithDrop { x: 0i8, y: 'a' }.x;
@@ -113,4 +96,6 @@ fn main() {
         EnumNoDrop::A(x) => x,
         EnumNoDrop::B(x) => x as f64
     };
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/generic-functions.rs b/src/test/codegen-units/item-collection/generic-functions.rs
index 41133f0f797..8efe4b2762a 100644
--- a/src/test/codegen-units/item-collection/generic-functions.rs
+++ b/src/test/codegen-units/item-collection/generic-functions.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 fn foo1<T1>(a: T1) -> (T1, u32) {
     (a, 1)
@@ -31,27 +32,9 @@ pub fn lifetime_only<'a>(a: &'a u32) -> &'a u32 {
     a
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ generic_functions0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ generic_functions0[Internal]
-//~ TRANS_ITEM fn generic_functions::main[0]
-fn main() {
+//~ TRANS_ITEM fn generic_functions::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn generic_functions::foo1[0]<i32>
     let _ = foo1(2i32);
     //~ TRANS_ITEM fn generic_functions::foo1[0]<i64>
@@ -78,4 +61,6 @@ fn main() {
     let _ = foo3(0i16, "a", 2usize);
     //~ TRANS_ITEM fn generic_functions::foo3[0]<char, (), ()>
     let _ = foo3('v', (), ());
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/generic-impl.rs b/src/test/codegen-units/item-collection/generic-impl.rs
index 6212ad0417c..d1ee8ee624c 100644
--- a/src/test/codegen-units/item-collection/generic-impl.rs
+++ b/src/test/codegen-units/item-collection/generic-impl.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 struct Struct<T> {
     x: T,
@@ -50,27 +51,9 @@ impl<'a> LifeTimeOnly<'a> {
     pub fn non_instantiated<T>(&self) {}
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ generic_impl0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ generic_impl0[Internal]
-//~ TRANS_ITEM fn generic_impl::main[0]
-fn main() {
+//~ TRANS_ITEM fn generic_impl::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn generic_impl::{{impl}}[0]::new[0]<i32>
     //~ TRANS_ITEM fn generic_impl::id[0]<i32>
     //~ TRANS_ITEM fn generic_impl::{{impl}}[0]::get[0]<i32, i16>
@@ -94,4 +77,6 @@ fn main() {
     //~ TRANS_ITEM fn generic_impl::{{impl}}[0]::new[0]<generic_impl::Struct[0]<&str>>
     //~ TRANS_ITEM fn generic_impl::id[0]<generic_impl::Struct[0]<&str>>
     let _ = (Struct::new(Struct::new("str")).f)(Struct::new("str"));
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/impl-in-non-instantiated-generic.rs b/src/test/codegen-units/item-collection/impl-in-non-instantiated-generic.rs
index aa3de2095fb..c07d26c3f8d 100644
--- a/src/test/codegen-units/item-collection/impl-in-non-instantiated-generic.rs
+++ b/src/test/codegen-units/item-collection/impl-in-non-instantiated-generic.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 trait SomeTrait {
     fn foo(&self);
@@ -28,26 +29,10 @@ pub fn generic_function<T>(x: T) -> (T, i32) {
     (x, 0)
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ impl_in_non_instantiated_generic0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ impl_in_non_instantiated_generic0[Internal]
-//~ TRANS_ITEM fn impl_in_non_instantiated_generic::main[0]
-fn main() {
+//~ TRANS_ITEM fn impl_in_non_instantiated_generic::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     0i64.foo();
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/instantiation-through-vtable.rs b/src/test/codegen-units/item-collection/instantiation-through-vtable.rs
index 8b46984f72f..2e1138ef128 100644
--- a/src/test/codegen-units/item-collection/instantiation-through-vtable.rs
+++ b/src/test/codegen-units/item-collection/instantiation-through-vtable.rs
@@ -13,6 +13,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![deny(dead_code)]
+#![feature(start)]
 
 trait Trait {
     fn foo(&self) -> u32;
@@ -28,27 +29,9 @@ impl<T> Trait for Struct<T> {
     fn bar(&self) {}
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ instantiation_through_vtable0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ instantiation_through_vtable0[Internal]
-//~ TRANS_ITEM fn instantiation_through_vtable::main[0]
-fn main() {
+//~ TRANS_ITEM fn instantiation_through_vtable::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     let s1 = Struct { _a: 0u32 };
 
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<instantiation_through_vtable::Struct[0]<u32>> @@ instantiation_through_vtable0[Internal]
@@ -61,4 +44,6 @@ fn main() {
     //~ TRANS_ITEM fn instantiation_through_vtable::{{impl}}[0]::foo[0]<u64>
     //~ TRANS_ITEM fn instantiation_through_vtable::{{impl}}[0]::bar[0]<u64>
     let _ = &s1 as &Trait;
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/items-within-generic-items.rs b/src/test/codegen-units/item-collection/items-within-generic-items.rs
index abd79dd39d6..04b54de3ce2 100644
--- a/src/test/codegen-units/item-collection/items-within-generic-items.rs
+++ b/src/test/codegen-units/item-collection/items-within-generic-items.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 fn generic_fn<T>(a: T) -> (T, i32) {
     //~ TRANS_ITEM fn items_within_generic_items::generic_fn[0]::nested_fn[0]
@@ -31,31 +32,15 @@ fn generic_fn<T>(a: T) -> (T, i32) {
     return (a, x + nested_fn(0));
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ items_within_generic_items0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ items_within_generic_items0[Internal]
-//~ TRANS_ITEM fn items_within_generic_items::main[0]
-fn main() {
+//~ TRANS_ITEM fn items_within_generic_items::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn items_within_generic_items::generic_fn[0]<i64>
     let _ = generic_fn(0i64);
     //~ TRANS_ITEM fn items_within_generic_items::generic_fn[0]<u16>
     let _ = generic_fn(0u16);
     //~ TRANS_ITEM fn items_within_generic_items::generic_fn[0]<i8>
     let _ = generic_fn(0i8);
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/non-generic-closures.rs b/src/test/codegen-units/item-collection/non-generic-closures.rs
index 278e9189dd6..f0121d56cec 100644
--- a/src/test/codegen-units/item-collection/non-generic-closures.rs
+++ b/src/test/codegen-units/item-collection/non-generic-closures.rs
@@ -17,6 +17,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 //~ TRANS_ITEM fn non_generic_closures::temporary[0]
 fn temporary() {
@@ -52,12 +53,15 @@ fn assigned_to_variable_executed_directly() {
     f(4);
 }
 
-//~ TRANS_ITEM fn non_generic_closures::main[0]
-fn main() {
+//~ TRANS_ITEM fn non_generic_closures::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     temporary();
     assigned_to_variable_but_not_executed();
     assigned_to_variable_executed_directly();
     assigned_to_variable_executed_indirectly();
+
+    0
 }
 
 //~ TRANS_ITEM fn non_generic_closures::run_closure[0]
diff --git a/src/test/codegen-units/item-collection/non-generic-drop-glue.rs b/src/test/codegen-units/item-collection/non-generic-drop-glue.rs
index df89b3fca9f..bf084aa96ea 100644
--- a/src/test/codegen-units/item-collection/non-generic-drop-glue.rs
+++ b/src/test/codegen-units/item-collection/non-generic-drop-glue.rs
@@ -13,6 +13,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![deny(dead_code)]
+#![feature(start)]
 
 //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<non_generic_drop_glue::StructWithDrop[0]> @@ non_generic_drop_glue0[Internal]
 struct StructWithDrop {
@@ -42,27 +43,9 @@ enum EnumNoDrop {
     A(i32)
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ non_generic_drop_glue0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ non_generic_drop_glue0[Internal]
-//~ TRANS_ITEM fn non_generic_drop_glue::main[0]
-fn main() {
+//~ TRANS_ITEM fn non_generic_drop_glue::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     let _ = StructWithDrop { x: 0 }.x;
     let _ = StructNoDrop { x: 0 }.x;
     let _ = match EnumWithDrop::A(0) {
@@ -71,4 +54,6 @@ fn main() {
     let _ = match EnumNoDrop::A(0) {
         EnumNoDrop::A(x) => x
     };
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/non-generic-functions.rs b/src/test/codegen-units/item-collection/non-generic-functions.rs
index 6f254ffde60..8c487db5c96 100644
--- a/src/test/codegen-units/item-collection/non-generic-functions.rs
+++ b/src/test/codegen-units/item-collection/non-generic-functions.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 //~ TRANS_ITEM fn non_generic_functions::foo[0]
 fn foo() {
@@ -69,30 +70,14 @@ impl Struct {
     }
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ non_generic_functions0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ non_generic_functions0[Internal]
-//~ TRANS_ITEM fn non_generic_functions::main[0]
-fn main() {
+//~ TRANS_ITEM fn non_generic_functions::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     foo();
     bar();
     Struct::foo();
     let x = Struct { _x: 0 };
     x.bar();
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/static-init.rs b/src/test/codegen-units/item-collection/static-init.rs
index 9921c9b84d2..5ff7c3480b1 100644
--- a/src/test/codegen-units/item-collection/static-init.rs
+++ b/src/test/codegen-units/item-collection/static-init.rs
@@ -11,6 +11,8 @@
 // compile-flags:-Zprint-trans-items=eager
 // ignore-tidy-linelength
 
+#![feature(start)]
+
 pub static FN : fn() = foo::<i32>;
 
 pub fn foo<T>() { }
@@ -18,25 +20,9 @@ pub fn foo<T>() { }
 //~ TRANS_ITEM fn static_init::foo[0]<i32>
 //~ TRANS_ITEM static static_init::FN[0]
 
-fn main() { }
+//~ TRANS_ITEM fn static_init::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
+    0
+}
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ static_init0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ static_init0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ static_init0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ static_init0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ static_init0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ static_init0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ static_init0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ static_init0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ static_init0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ static_init0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ static_init0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ static_init0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ static_init0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ static_init0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ static_init0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ static_init0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ static_init0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ static_init0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ static_init0[Internal]
-//~ TRANS_ITEM fn static_init::main[0]
diff --git a/src/test/codegen-units/item-collection/statics-and-consts.rs b/src/test/codegen-units/item-collection/statics-and-consts.rs
index bd3dcd2fe79..11df1da3a78 100644
--- a/src/test/codegen-units/item-collection/statics-and-consts.rs
+++ b/src/test/codegen-units/item-collection/statics-and-consts.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 static STATIC1: i64 = {
     const STATIC1_CONST1: i64 = 2;
@@ -47,9 +48,13 @@ fn foo() {
     };
 }
 
-fn main() {
+//~ TRANS_ITEM fn statics_and_consts::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     foo();
     let _ = STATIC1;
+
+    0
 }
 
 //~ TRANS_ITEM static statics_and_consts::STATIC1[0]
@@ -58,24 +63,3 @@ fn main() {
 //~ TRANS_ITEM static statics_and_consts::foo[0]::STATIC2[0]
 //~ TRANS_ITEM static statics_and_consts::foo[0]::STATIC2[1]
 //~ TRANS_ITEM static statics_and_consts::foo[0]::STATIC2[2]
-
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ statics_and_consts0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ statics_and_consts0[Internal]
-//~ TRANS_ITEM fn statics_and_consts::main[0]
diff --git a/src/test/codegen-units/item-collection/trait-implementations.rs b/src/test/codegen-units/item-collection/trait-implementations.rs
index e8f727cbd12..8eb33dd647f 100644
--- a/src/test/codegen-units/item-collection/trait-implementations.rs
+++ b/src/test/codegen-units/item-collection/trait-implementations.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 pub trait SomeTrait {
     fn foo(&self);
@@ -55,27 +56,9 @@ impl<T> SomeGenericTrait<T> for f32 {
     fn bar<T2>(&self, _: T, _: T2) {}
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ trait_implementations0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ trait_implementations0[Internal]
-//~ TRANS_ITEM fn trait_implementations::main[0]
-fn main() {
+//~ TRANS_ITEM fn trait_implementations::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
    //~ TRANS_ITEM fn trait_implementations::{{impl}}[1]::bar[0]<char>
    0i32.bar('x');
 
@@ -96,4 +79,6 @@ fn main() {
 
    //~ TRANS_ITEM fn trait_implementations::{{impl}}[3]::bar[0]<&str, &str>
    0f32.bar("&str", "&str");
+
+   0
 }
diff --git a/src/test/codegen-units/item-collection/trait-method-as-argument.rs b/src/test/codegen-units/item-collection/trait-method-as-argument.rs
index f6e3c1cf974..10b21630308 100644
--- a/src/test/codegen-units/item-collection/trait-method-as-argument.rs
+++ b/src/test/codegen-units/item-collection/trait-method-as-argument.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 trait Trait : Sized {
     fn foo(self) -> Self { self }
@@ -36,27 +37,9 @@ fn take_foo_mut<T, F: FnMut(T) -> T>(mut f: F, arg: T) -> T {
     (f)(arg)
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ trait_method_as_argument0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ trait_method_as_argument0[Internal]
-//~ TRANS_ITEM fn trait_method_as_argument::main[0]
-fn main() {
+//~ TRANS_ITEM fn trait_method_as_argument::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn trait_method_as_argument::take_foo_once[0]<u32, fn(u32) -> u32>
     //~ TRANS_ITEM fn trait_method_as_argument::{{impl}}[0]::foo[0]
     //~ TRANS_ITEM fn core::ops[0]::function[0]::FnOnce[0]::call_once[0]<fn(u32) -> u32, (u32)>
@@ -82,4 +65,6 @@ fn main() {
     //~ TRANS_ITEM fn trait_method_as_argument::take_foo_mut[0]<char, fn(char) -> char>
     //~ TRANS_ITEM fn core::ops[0]::function[0]::FnMut[0]::call_mut[0]<fn(u32) -> u32, (u32)>
     take_foo_mut(Trait::foo, 'c');
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/trait-method-default-impl.rs b/src/test/codegen-units/item-collection/trait-method-default-impl.rs
index 6e6793076da..a6ae3765b2e 100644
--- a/src/test/codegen-units/item-collection/trait-method-default-impl.rs
+++ b/src/test/codegen-units/item-collection/trait-method-default-impl.rs
@@ -12,6 +12,7 @@
 // compile-flags:-Zprint-trans-items=eager
 
 #![deny(dead_code)]
+#![feature(start)]
 
 trait SomeTrait {
     fn foo(&self) { }
@@ -46,27 +47,9 @@ impl<T1> SomeGenericTrait<T1> for u32 {
     // since nothing is monomorphic here, nothing should be generated unless used somewhere.
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ trait_method_default_impl0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ trait_method_default_impl0[Internal]
-//~ TRANS_ITEM fn trait_method_default_impl::main[0]
-fn main() {
+//~ TRANS_ITEM fn trait_method_default_impl::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn trait_method_default_impl::SomeTrait[0]::bar[0]<i8, char>
     let _ = 1i8.bar('c');
 
@@ -84,4 +67,6 @@ fn main() {
 
     //~ TRANS_ITEM fn trait_method_default_impl::SomeGenericTrait[0]::bar[0]<u32, i16, ()>
     0u32.bar(0i16, ());
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/transitive-drop-glue.rs b/src/test/codegen-units/item-collection/transitive-drop-glue.rs
index e966b9f92e4..57cd10187a2 100644
--- a/src/test/codegen-units/item-collection/transitive-drop-glue.rs
+++ b/src/test/codegen-units/item-collection/transitive-drop-glue.rs
@@ -13,6 +13,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![deny(dead_code)]
+#![feature(start)]
 
 //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<transitive_drop_glue::Root[0]> @@ transitive_drop_glue0[Internal]
 struct Root(Intermediate);
@@ -34,28 +35,9 @@ impl<T> Drop for LeafGen<T> {
     fn drop(&mut self) {}
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ transitive_drop_glue0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ transitive_drop_glue0[Internal]
-//~ TRANS_ITEM fn transitive_drop_glue::main[0]
-fn main() {
-
+//~ TRANS_ITEM fn transitive_drop_glue::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     let _ = Root(Intermediate(Leaf));
 
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<transitive_drop_glue::RootGen[0]<u32>> @@ transitive_drop_glue0[Internal]
@@ -69,4 +51,6 @@ fn main() {
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<transitive_drop_glue::LeafGen[0]<i16>> @@ transitive_drop_glue0[Internal]
     //~ TRANS_ITEM fn transitive_drop_glue::{{impl}}[1]::drop[0]<i16>
     let _ = RootGen(IntermediateGen(LeafGen(0i16)));
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/tuple-drop-glue.rs b/src/test/codegen-units/item-collection/tuple-drop-glue.rs
index 93b3f832e99..a5f2409b8ae 100644
--- a/src/test/codegen-units/item-collection/tuple-drop-glue.rs
+++ b/src/test/codegen-units/item-collection/tuple-drop-glue.rs
@@ -13,6 +13,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![deny(dead_code)]
+#![feature(start)]
 
 //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<tuple_drop_glue::Dropped[0]> @@ tuple_drop_glue0[Internal]
 struct Dropped;
@@ -22,31 +23,15 @@ impl Drop for Dropped {
     fn drop(&mut self) {}
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ tuple_drop_glue0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ tuple_drop_glue0[Internal]
-//~ TRANS_ITEM fn tuple_drop_glue::main[0]
-fn main() {
+//~ TRANS_ITEM fn tuple_drop_glue::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<(u32, tuple_drop_glue::Dropped[0])> @@ tuple_drop_glue0[Internal]
     let x = (0u32, Dropped);
 
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<(i16, (tuple_drop_glue::Dropped[0], bool))> @@ tuple_drop_glue0[Internal]
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<(tuple_drop_glue::Dropped[0], bool)> @@ tuple_drop_glue0[Internal]
     let x = (0i16, (Dropped, true));
+
+    0
 }
diff --git a/src/test/codegen-units/item-collection/unsizing.rs b/src/test/codegen-units/item-collection/unsizing.rs
index 4c07177b739..87d2581e1f8 100644
--- a/src/test/codegen-units/item-collection/unsizing.rs
+++ b/src/test/codegen-units/item-collection/unsizing.rs
@@ -15,6 +15,7 @@
 #![deny(dead_code)]
 #![feature(coerce_unsized)]
 #![feature(unsize)]
+#![feature(start)]
 
 use std::marker::Unsize;
 use std::ops::CoerceUnsized;
@@ -53,28 +54,9 @@ struct Wrapper<T: ?Sized>(*const T);
 
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Wrapper<U>> for Wrapper<T> {}
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ unsizing0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ unsizing0[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ unsizing0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ unsizing0[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ unsizing0[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ unsizing0[Internal]
-//~ TRANS_ITEM fn unsizing::main[0]
-fn main()
-{
+//~ TRANS_ITEM fn unsizing::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     // simple case
     let bool_sized = &true;
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<bool> @@ unsizing0[Internal]
@@ -102,4 +84,6 @@ fn main()
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<u32> @@ unsizing0[Internal]
     //~ TRANS_ITEM fn unsizing::{{impl}}[3]::foo[0]
     let _wrapper_sized = wrapper_sized as Wrapper<Trait>;
+
+    0
 }
diff --git a/src/test/codegen-units/partitioning/methods-are-with-self-type.rs b/src/test/codegen-units/partitioning/methods-are-with-self-type.rs
index 1ea5aafd401..aa01289de59 100644
--- a/src/test/codegen-units/partitioning/methods-are-with-self-type.rs
+++ b/src/test/codegen-units/partitioning/methods-are-with-self-type.rs
@@ -19,6 +19,7 @@
 // compile-flags:-Zprint-trans-items=lazy -Zincremental=tmp/partitioning-tests/methods-are-with-self-type
 
 #![allow(dead_code)]
+#![feature(start)]
 
 struct SomeType;
 
@@ -63,9 +64,9 @@ mod type2 {
     pub struct Struct;
 }
 
-//~ TRANS_ITEM fn methods_are_with_self_type::main[0]
-fn main()
-{
+//~ TRANS_ITEM fn methods_are_with_self_type::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn methods_are_with_self_type::mod1[0]::{{impl}}[1]::method[0]<u32, u64> @@ methods_are_with_self_type.volatile[WeakODR]
     SomeGenericType(0u32, 0u64).method();
     //~ TRANS_ITEM fn methods_are_with_self_type::mod1[0]::{{impl}}[1]::associated_fn[0]<char, &str> @@ methods_are_with_self_type.volatile[WeakODR]
@@ -80,6 +81,8 @@ fn main()
     type1::Struct.default();
     //~ TRANS_ITEM fn methods_are_with_self_type::Trait[0]::default[0]<methods_are_with_self_type::type2[0]::Struct[0]> @@ methods_are_with_self_type-type2.volatile[WeakODR]
     type2::Struct.default();
+
+    0
 }
 
 //~ TRANS_ITEM drop-glue i8
diff --git a/src/test/codegen-units/partitioning/vtable-through-const.rs b/src/test/codegen-units/partitioning/vtable-through-const.rs
index 05c36810c1f..d0acddda637 100644
--- a/src/test/codegen-units/partitioning/vtable-through-const.rs
+++ b/src/test/codegen-units/partitioning/vtable-through-const.rs
@@ -18,6 +18,8 @@
 // This test case makes sure, that references made through constants are
 // recorded properly in the InliningMap.
 
+#![feature(start)]
+
 mod mod1 {
     pub trait Trait1 {
         fn do_something(&self) {}
@@ -38,7 +40,7 @@ mod mod1 {
 
     fn id<T>(x: T) -> T { x }
 
-    // These are referenced, so they produce trans-items (see main())
+    // These are referenced, so they produce trans-items (see start())
     pub const TRAIT1_REF: &'static Trait1 = &0u32 as &Trait1;
     pub const TRAIT1_GEN_REF: &'static Trait1Gen<u8> = &0u32 as &Trait1Gen<u8>;
     pub const ID_CHAR: fn(char) -> char = id::<char>;
@@ -68,27 +70,9 @@ mod mod1 {
     pub const ID_I64: fn(i64) -> i64 = id::<i64>;
 }
 
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::align[0] @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::from_size_align_unchecked[0] @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn alloc::allocator[0]::{{impl}}[0]::size[0] @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::box_free[0]<core::any[0]::Any[0]> @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn alloc::heap[0]::{{impl}}[0]::dealloc[0] @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn core::mem[0]::uninitialized[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ std-panicking.volatile[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::any[0]::Any[0]> @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<core::result[0]::Result[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>>> @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::read[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ std-panicking.volatile[Internal]
-//~ TRANS_ITEM fn core::ptr[0]::write[0]<i32> @@ std-panicking.volatile[Internal]
-//~ TRANS_ITEM fn core::result[0]::{{impl}}[0]::unwrap_or[0]<i32, alloc::boxed[0]::Box[0]<core::any[0]::Any[0]>> @@ std-rt.volatile[Internal]
-//~ TRANS_ITEM fn std::panic[0]::catch_unwind[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ std-panic.volatile[External]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]::do_call[0]<std::rt[0]::lang_start[0]::{{closure}}[0]<()>, i32> @@ std-panicking.volatile[Internal]
-//~ TRANS_ITEM fn std::panicking[0]::try[0]<i32, std::rt[0]::lang_start[0]::{{closure}}[0]<()>> @@ std-panicking.volatile[External]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, fn()> @@ std-sys_common-backtrace.volatile[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]::{{closure}}[0]<(), i32, extern "rust-call" fn(()) -> i32, &fn()> @@ std-panicking.volatile[Internal]
-//~ TRANS_ITEM fn std::rt[0]::lang_start[0]<()> @@ std-rt.volatile[External]
-//~ TRANS_ITEM fn std::sys_common[0]::backtrace[0]::__rust_begin_short_backtrace[0]<std::rt[0]::lang_start[0]::{{closure}}[0]::{{closure}}[0]<()>, i32> @@ std-sys_common-backtrace.volatile[External]
-//~ TRANS_ITEM fn vtable_through_const::main[0] @@ vtable_through_const[Internal]
-fn main() {
+//~ TRANS_ITEM fn vtable_through_const::start[0]
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<u32> @@ vtable_through_const[Internal]
 
     // Since Trait1::do_something() is instantiated via its default implementation,
@@ -109,4 +93,6 @@ fn main() {
 
     //~ TRANS_ITEM fn vtable_through_const::mod1[0]::id[0]<char> @@ vtable_through_const-mod1.volatile[External]
     mod1::ID_CHAR('x');
+
+    0
 }