Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 94 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-40883.rs b/tests/ui/issues/issue-40883.rs
new file mode 100644
index 000000000..8a4aef46d
--- /dev/null
+++ b/tests/ui/issues/issue-40883.rs
@@ -0,0 +1,94 @@
+// run-pass
+#![allow(dead_code)]
+// check that we don't have linear stack usage with multiple calls to `push`
+
+#![feature(test)]
+
+extern crate test;
+use std::mem;
+
+fn meal() -> Big {
+    if test::black_box(false) {
+        panic!()
+    }
+    Big { drop_me: [
+        None, None, None, None, None, None, None, None,
+        None, None, None, None, None, None, None, None,
+        None, None, None, None, None, None, None, None,
+        None, None, None, None, None, None, None, None,
+        None, None, None, None, None, None, None, None,
+        None, None, None, None, None, None, None, None,
+    ]}
+}
+
+pub struct Big {
+    drop_me: [Option<Box<u8>>; 48],
+}
+
+#[inline]
+fn push(out: &mut Vec<Big>) {
+    out.push(meal());
+}
+
+#[inline(never)]
+pub fn supersize_me(out: &mut Vec<Big>) {
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out); // 16 calls to `push`
+
+    verify_stack_usage(out);
+
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out);
+    push(out); // 16 calls to `push`
+}
+
+#[inline(never)]
+fn verify_stack_usage(before_ptr: *mut Vec<Big>) {
+    // To check stack usage, create locals before and after
+    // and check the difference in addresses between them.
+    let mut stack_var: Vec<Big> = vec![];
+    test::black_box(&mut stack_var);
+    let stack_usage = isize::abs(
+        (&mut stack_var as *mut _ as isize) -
+            (before_ptr as isize)) as usize;
+    // Give space for 2 copies of `Big` + 272 "misc" bytes
+    // (value observed on x86_64-pc-windows-gnu).
+    if stack_usage > mem::size_of::<Big>() * 2 + 272 {
+        panic!("used {} bytes of stack, but `struct Big` is only {} bytes",
+               stack_usage, mem::size_of::<Big>());
+    }
+
+}
+
+pub fn main() {
+    let mut v = vec![];
+    test::black_box(&mut v);
+    supersize_me(&mut v);
+}