diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
index d3b06d7..e80a435 100644
--- a/.cargo_vcs_info.json
+++ b/.cargo_vcs_info.json
@@ -1,6 +1,6 @@
 {
   "git": {
-    "sha1": "de0c79d171e95d1cbbd4becf678cc43ea689551e"
+    "sha1": "f910d25edb04d05a24c9e58d73a4e5d8a31163a6"
   },
   "path_in_vcs": ""
 }
\ No newline at end of file
diff --git a/Android.bp b/Android.bp
index 8c176c1..a46517c 100644
--- a/Android.bp
+++ b/Android.bp
@@ -42,7 +42,7 @@
     host_supported: true,
     crate_name: "async_task",
     cargo_env_compat: true,
-    cargo_pkg_version: "4.2.0",
+    cargo_pkg_version: "4.3.0",
     srcs: ["src/lib.rs"],
     edition: "2018",
     features: [
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe87187..d0a3e0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+# Version 4.3.0
+
+- Bump MSRV to Rust 1.47. (#30)
+- Evaluate the layouts for the tasks at compile time. (#30)
+- Add layout_info field to TaskVTable so that debuggers can decode raw tasks. (#29)
+
 # Version 4.2.0
 
 - Add `Task::is_finished`. (#19)
diff --git a/Cargo.lock.saved b/Cargo.lock.saved
new file mode 100644
index 0000000..388f5ba
--- /dev/null
+++ b/Cargo.lock.saved
@@ -0,0 +1,443 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "async-channel"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2114d64672151c0c5eaa5e131ec84a74f06e1e559830dabba01ca30605d66319"
+dependencies = [
+ "concurrent-queue",
+ "event-listener",
+ "futures-core",
+]
+
+[[package]]
+name = "async-executor"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "871f9bb5e0a22eeb7e8cf16641feb87c9dc67032ccf8ff49e772eb9941d3a965"
+dependencies = [
+ "async-task 4.2.0",
+ "concurrent-queue",
+ "fastrand",
+ "futures-lite",
+ "once_cell",
+ "slab",
+]
+
+[[package]]
+name = "async-fs"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b3ca4f8ff117c37c278a2f7415ce9be55560b846b5bc4412aaa5d29c1c3dae2"
+dependencies = [
+ "async-lock",
+ "blocking",
+ "futures-lite",
+]
+
+[[package]]
+name = "async-io"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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+dependencies = [
+ "concurrent-queue",
+ "futures-lite",
+ "libc",
+ "log",
+ "once_cell",
+ "parking",
+ "polling",
+ "slab",
+ "socket2",
+ "waker-fn",
+ "winapi",
+]
+
+[[package]]
+name = "async-lock"
+version = "2.5.0"
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+dependencies = [
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+
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+ "cfg-if",
+ "event-listener",
+ "futures-lite",
+ "libc",
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+ "signal-hook",
+ "winapi",
+]
+
+[[package]]
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+
+[[package]]
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+dependencies = [
+ "atomic-waker",
+ "easy-parallel",
+ "flaky_test",
+ "flume",
+ "once_cell",
+ "smol",
+]
+
+[[package]]
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+dependencies = [
+ "async-channel",
+ "async-task 4.2.0",
+ "atomic-waker",
+ "fastrand",
+ "futures-lite",
+ "once_cell",
+]
+
+[[package]]
+name = "cache-padded"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1db59621ec70f09c5e9b597b220c7a2b43611f4710dc03ceb8748637775692c"
+
+[[package]]
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+
+[[package]]
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+ "futures-io",
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+ "async-channel",
+ "async-executor",
+ "async-fs",
+ "async-io",
+ "async-lock",
+ "async-net",
+ "async-process",
+ "blocking",
+ "futures-lite",
+ "once_cell",
+]
+
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+ "libc",
+ "winapi",
+]
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+ "lock_api",
+]
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+ "cc",
+]
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+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/Cargo.toml b/Cargo.toml
index 7847dd8..6e989e5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,12 +11,13 @@
 
 [package]
 edition = "2018"
-rust-version = "1.39"
+rust-version = "1.47"
 name = "async-task"
-version = "4.2.0"
+version = "4.3.0"
 authors = ["Stjepan Glavina <stjepang@gmail.com>"]
 exclude = ["/.*"]
 description = "Task abstraction for building executors"
+readme = "README.md"
 keywords = [
     "futures",
     "task",
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
index 7dc7c73..8c611bf 100644
--- a/Cargo.toml.orig
+++ b/Cargo.toml.orig
@@ -3,10 +3,10 @@
 # When publishing a new version:
 # - Update CHANGELOG.md
 # - Create "v4.x.y" git tag
-version = "4.2.0"
+version = "4.3.0"
 authors = ["Stjepan Glavina <stjepang@gmail.com>"]
 edition = "2018"
-rust-version = "1.39"
+rust-version = "1.47"
 license = "Apache-2.0 OR MIT"
 repository = "https://github.com/smol-rs/async-task"
 description = "Task abstraction for building executors"
diff --git a/METADATA b/METADATA
index 9a5cdf5..799c6da 100644
--- a/METADATA
+++ b/METADATA
@@ -1,3 +1,7 @@
+# This project was upgraded with external_updater.
+# Usage: tools/external_updater/updater.sh update rust/crates/async-task
+# For more info, check https://cs.android.com/android/platform/superproject/+/master:tools/external_updater/README.md
+
 name: "async_task"
 description: "Task abstraction for building executors"
 third_party {
@@ -7,13 +11,13 @@
   }
   url {
     type: ARCHIVE
-    value: "https://static.crates.io/crates/async_task/async_task-4.2.0.crate"
+    value: "https://static.crates.io/crates/async_task/async_task-4.3.0.crate"
   }
-  version: "4.2.0"
+  version: "4.3.0"
   license_type: NOTICE
   last_upgrade_date {
     year: 2022
-    month: 6
-    day: 22
+    month: 12
+    day: 6
   }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 4a868bf..dd689ec 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -74,6 +74,17 @@
 
 extern crate alloc;
 
+/// We can't use `?` in const contexts yet, so this macro acts
+/// as a workaround.
+macro_rules! leap {
+    ($x: expr) => {{
+        match ($x) {
+            Some(val) => val,
+            None => return None,
+        }
+    }};
+}
+
 mod header;
 mod raw;
 mod runnable;
diff --git a/src/raw.rs b/src/raw.rs
index 9b5854c..bb031da 100644
--- a/src/raw.rs
+++ b/src/raw.rs
@@ -1,4 +1,4 @@
-use alloc::alloc::Layout;
+use alloc::alloc::Layout as StdLayout;
 use core::cell::UnsafeCell;
 use core::future::Future;
 use core::mem::{self, ManuallyDrop};
@@ -9,7 +9,7 @@
 
 use crate::header::Header;
 use crate::state::*;
-use crate::utils::{abort, abort_on_panic, extend};
+use crate::utils::{abort, abort_on_panic, max, Layout};
 use crate::Runnable;
 
 /// The vtable for a task.
@@ -34,6 +34,12 @@
 
     /// Creates a new waker associated with the task.
     pub(crate) clone_waker: unsafe fn(ptr: *const ()) -> RawWaker,
+
+    /// The memory layout of the task. This information enables
+    /// debuggers to decode raw task memory blobs. Do not remove
+    /// the field, even if it appears to be unused.
+    #[allow(unused)]
+    pub(crate) layout_info: &'static Option<TaskLayout>,
 }
 
 /// Memory layout of a task.
@@ -45,7 +51,7 @@
 #[derive(Clone, Copy)]
 pub(crate) struct TaskLayout {
     /// Memory layout of the whole task.
-    pub(crate) layout: Layout,
+    pub(crate) layout: StdLayout,
 
     /// Offset into the task at which the schedule function is stored.
     pub(crate) offset_s: usize,
@@ -80,6 +86,39 @@
     }
 }
 
+impl<F, T, S> RawTask<F, T, S> {
+    const TASK_LAYOUT: Option<TaskLayout> = Self::eval_task_layout();
+
+    /// Computes the memory layout for a task.
+    #[inline]
+    const fn eval_task_layout() -> Option<TaskLayout> {
+        // Compute the layouts for `Header`, `S`, `F`, and `T`.
+        let layout_header = Layout::new::<Header>();
+        let layout_s = Layout::new::<S>();
+        let layout_f = Layout::new::<F>();
+        let layout_r = Layout::new::<T>();
+
+        // Compute the layout for `union { F, T }`.
+        let size_union = max(layout_f.size(), layout_r.size());
+        let align_union = max(layout_f.align(), layout_r.align());
+        let layout_union = Layout::from_size_align(size_union, align_union);
+
+        // Compute the layout for `Header` followed `S` and `union { F, T }`.
+        let layout = layout_header;
+        let (layout, offset_s) = leap!(layout.extend(layout_s));
+        let (layout, offset_union) = leap!(layout.extend(layout_union));
+        let offset_f = offset_union;
+        let offset_r = offset_union;
+
+        Some(TaskLayout {
+            layout: unsafe { layout.into_std() },
+            offset_s,
+            offset_f,
+            offset_r,
+        })
+    }
+}
+
 impl<F, T, S> RawTask<F, T, S>
 where
     F: Future<Output = T>,
@@ -97,7 +136,9 @@
     /// It is assumed that initially only the `Runnable` and the `Task` exist.
     pub(crate) fn allocate(future: F, schedule: S) -> NonNull<()> {
         // Compute the layout of the task for allocation. Abort if the computation fails.
-        let task_layout = abort_on_panic(|| Self::task_layout());
+        //
+        // n.b. notgull: task_layout now automatically aborts instead of panicking
+        let task_layout = Self::task_layout();
 
         unsafe {
             // Allocate enough space for the entire task.
@@ -120,6 +161,7 @@
                     destroy: Self::destroy,
                     run: Self::run,
                     clone_waker: Self::clone_waker,
+                    layout_info: &Self::TASK_LAYOUT,
                 },
             });
 
@@ -149,32 +191,12 @@
         }
     }
 
-    /// Returns the memory layout for a task.
+    /// Returns the layout of the task.
     #[inline]
     fn task_layout() -> TaskLayout {
-        // Compute the layouts for `Header`, `S`, `F`, and `T`.
-        let layout_header = Layout::new::<Header>();
-        let layout_s = Layout::new::<S>();
-        let layout_f = Layout::new::<F>();
-        let layout_r = Layout::new::<T>();
-
-        // Compute the layout for `union { F, T }`.
-        let size_union = layout_f.size().max(layout_r.size());
-        let align_union = layout_f.align().max(layout_r.align());
-        let layout_union = unsafe { Layout::from_size_align_unchecked(size_union, align_union) };
-
-        // Compute the layout for `Header` followed `S` and `union { F, T }`.
-        let layout = layout_header;
-        let (layout, offset_s) = extend(layout, layout_s);
-        let (layout, offset_union) = extend(layout, layout_union);
-        let offset_f = offset_union;
-        let offset_r = offset_union;
-
-        TaskLayout {
-            layout,
-            offset_s,
-            offset_f,
-            offset_r,
+        match Self::TASK_LAYOUT {
+            Some(tl) => tl,
+            None => abort(),
         }
     }
 
diff --git a/src/task.rs b/src/task.rs
index 7d1c433..8ecd746 100644
--- a/src/task.rs
+++ b/src/task.rs
@@ -99,6 +99,7 @@
     /// # Examples
     ///
     /// ```
+    /// # if cfg!(miri) { return; } // Miri does not support epoll
     /// use smol::{future, Executor, Timer};
     /// use std::thread;
     /// use std::time::Duration;
@@ -485,6 +486,7 @@
     /// # Examples
     ///
     /// ```
+    /// # if cfg!(miri) { return; } // Miri does not support epoll
     /// use smol::{future, Executor, Timer};
     /// use std::thread;
     /// use std::time::Duration;
diff --git a/src/utils.rs b/src/utils.rs
index cb9b65e..189e9af 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -1,4 +1,4 @@
-use core::alloc::Layout;
+use core::alloc::Layout as StdLayout;
 use core::mem;
 
 /// Aborts the process.
@@ -36,29 +36,92 @@
     t
 }
 
-/// Returns the layout for `a` followed by `b` and the offset of `b`.
-///
-/// This function was adapted from the currently unstable `Layout::extend()`:
-/// https://doc.rust-lang.org/nightly/std/alloc/struct.Layout.html#method.extend
-#[inline]
-pub(crate) fn extend(a: Layout, b: Layout) -> (Layout, usize) {
-    let new_align = a.align().max(b.align());
-    let pad = padding_needed_for(a, b.align());
-
-    let offset = a.size().checked_add(pad).unwrap();
-    let new_size = offset.checked_add(b.size()).unwrap();
-
-    let layout = Layout::from_size_align(new_size, new_align).unwrap();
-    (layout, offset)
+/// A version of `alloc::alloc::Layout` that can be used in the const
+/// position.
+#[derive(Clone, Copy, Debug)]
+pub(crate) struct Layout {
+    size: usize,
+    align: usize,
 }
 
-/// Returns the padding after `layout` that aligns the following address to `align`.
-///
-/// This function was adapted from the currently unstable `Layout::padding_needed_for()`:
-/// https://doc.rust-lang.org/nightly/std/alloc/struct.Layout.html#method.padding_needed_for
+impl Layout {
+    /// Creates a new `Layout` with the given size and alignment.
+    #[inline]
+    pub(crate) const fn from_size_align(size: usize, align: usize) -> Self {
+        Self { size, align }
+    }
+
+    /// Creates a new `Layout` for the given sized type.
+    #[inline]
+    pub(crate) const fn new<T>() -> Self {
+        Self::from_size_align(mem::size_of::<T>(), mem::align_of::<T>())
+    }
+
+    /// Convert this into the standard library's layout type.
+    ///
+    /// # Safety
+    ///
+    /// - `align` must be non-zero and a power of two.
+    /// - When rounded up to the nearest multiple of `align`, the size
+    ///   must not overflow.
+    #[inline]
+    pub(crate) const unsafe fn into_std(self) -> StdLayout {
+        StdLayout::from_size_align_unchecked(self.size, self.align)
+    }
+
+    /// Get the alignment of this layout.
+    #[inline]
+    pub(crate) const fn align(&self) -> usize {
+        self.align
+    }
+
+    /// Get the size of this layout.
+    #[inline]
+    pub(crate) const fn size(&self) -> usize {
+        self.size
+    }
+
+    /// Returns the layout for `a` followed by `b` and the offset of `b`.
+    ///
+    /// This function was adapted from the currently unstable `Layout::extend()`:
+    /// https://doc.rust-lang.org/nightly/std/alloc/struct.Layout.html#method.extend
+    #[inline]
+    pub(crate) const fn extend(self, other: Layout) -> Option<(Layout, usize)> {
+        let new_align = max(self.align(), other.align());
+        let pad = self.padding_needed_for(other.align());
+
+        let offset = leap!(self.size().checked_add(pad));
+        let new_size = leap!(offset.checked_add(other.size()));
+
+        // return None if any of the following are true:
+        // - align is 0 (implied false by is_power_of_two())
+        // - align is not a power of 2
+        // - size rounded up to align overflows
+        if !new_align.is_power_of_two() || new_size > core::usize::MAX - (new_align - 1) {
+            return None;
+        }
+
+        let layout = Layout::from_size_align(new_size, new_align);
+        Some((layout, offset))
+    }
+
+    /// Returns the padding after `layout` that aligns the following address to `align`.
+    ///
+    /// This function was adapted from the currently unstable `Layout::padding_needed_for()`:
+    /// https://doc.rust-lang.org/nightly/std/alloc/struct.Layout.html#method.padding_needed_for
+    #[inline]
+    pub(crate) const fn padding_needed_for(self, align: usize) -> usize {
+        let len = self.size();
+        let len_rounded_up = len.wrapping_add(align).wrapping_sub(1) & !align.wrapping_sub(1);
+        len_rounded_up.wrapping_sub(len)
+    }
+}
+
 #[inline]
-pub(crate) fn padding_needed_for(layout: Layout, align: usize) -> usize {
-    let len = layout.size();
-    let len_rounded_up = len.wrapping_add(align).wrapping_sub(1) & !align.wrapping_sub(1);
-    len_rounded_up.wrapping_sub(len)
+pub(crate) const fn max(left: usize, right: usize) -> usize {
+    if left > right {
+        left
+    } else {
+        right
+    }
 }