Bug 1945020 - build(rust): bump minimum Rust version 1.76 → 1.82 r=glandium

…but for ASAN/TSAN, use a hack: a 1.82.0 nightly commit that tolerates
`unsafe extern` blocks, but doesn't break our current toolchain patches.

We also remove the `host_or_target_str` check in
`build/moz.configure/toolchain.configure`, at @glandium's suggestion. To
quote him:

> [This] essentially undoes bug 1806040 but that bug predates other
> linker related changes, and I think the discrepancy host/target is not
> necessary anymore.

Differential Revision: https://phabricator.services.mozilla.com/D236028

Cargo.toml

@@ -57,7 +57,7 @@ exclude = [
 resolver = "2"
 
 [workspace.package]
-rust-version = "1.76.0"
+rust-version = "1.82.0"
 
 [workspace.dependencies]
 # Shared across multiple UniFFI consumers.

build/build-rust/rust-compiler-intrinsics.patch

@@ -0,0 +1,35 @@
+The version of `rustc` we build had some `compiler-builtins` updates that broke stuff. Later version
+of rustc in the 1.82 train landed more `compiler-builtins` updates that unbroke the stuff. We need at
+least some of that to make the version of rustc we landed on work.
+
+See also: <https://github.com/rust-lang/rust/pull/128691>
+
+diff --git a/library/alloc/Cargo.toml b/library/alloc/Cargo.toml
+index 479eb0a2ba..82d5893dc5 100644
+--- a/library/alloc/Cargo.toml
++++ b/library/alloc/Cargo.toml
+@@ -10,10 +10,7 @@
+ 
+ [dependencies]
+ core = { path = "../core" }
+-compiler_builtins = { version = "0.1.114", features = ['rustc-dep-of-std'] }
+-
+-[target.'cfg(not(any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")))'.dependencies]
+-compiler_builtins = { version = "0.1.114", features = ["no-f16-f128"] }
++compiler_builtins = { version = "0.1.117", features = ['rustc-dep-of-std'] }
+ 
+ [dev-dependencies]
+ rand = { version = "0.8.5", default-features = false, features = ["alloc"] }
+diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
+index fe601855cc..06e818fb7c 100644
+--- a/library/std/Cargo.toml
++++ b/library/std/Cargo.toml
+@@ -17,7 +17,7 @@
+ panic_unwind = { path = "../panic_unwind", optional = true }
+ panic_abort = { path = "../panic_abort" }
+ core = { path = "../core", public = true }
+-compiler_builtins = { version = "0.1.114" }
++compiler_builtins = { version = "0.1.117" }
+ profiler_builtins = { path = "../profiler_builtins", optional = true }
+ unwind = { path = "../unwind" }
+ hashbrown = { version = "0.14", default-features = false, features = [

build/build-rust/rust-vendor-std.patch

@@ -1,21 +1,21 @@
-Teaches Rust's build system to vendor std's dependencies into the
+Teaches Rust's build system to vendor `std`'s dependencies into the
-rust-src component.
+`rust-src` component.
 
-This was originally landed in https://github.com/rust-lang/rust/pull/78790
+This was originally landed in <https://github.com/rust-lang/rust/pull/78790>,
 but was backed out for causing some breakage for distro maintainers who
 need to build Rust itself in a vendored/offline context. It doesn't actually
-fetch anything interesting from crates.io, just the magic fake std/core crates
+fetch anything interesting from Crates.io, just the magic fake `std`/`core` crates
 that exist to make the build work right. Those crates *are* vendored but
 their contents are ignored in favour of the actual stdlib.
 
-For firefox's purposes, these patches still work fine, and are necessary
+For Firefox's purposes, these patches still work fine, and are necessary
-to make -Zbuild-std work in a vendored environment.
+to make `-Zbuild-std` work in a vendored environment.
 
 diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs
-index 012d64e5344..aedb53358ef 100644
+index 58f86aa996d..ef8c1584011 100644
 --- a/src/bootstrap/src/core/build_steps/dist.rs
 +++ b/src/bootstrap/src/core/build_steps/dist.rs
-@@ -927,6 +927,31 @@ fn run(self, builder: &Builder<'_>) -> GeneratedTarball {
+@@ -941,6 +941,35 @@ fn run(self, builder: &Builder<'_>) -> GeneratedTarball {
              builder.copy_link(&builder.src.join(file), &dst_src.join(file));
          }
  
@@ -40,7 +40,11 @@ index 012d64e5344..aedb53358ef 100644
 +        cmd.env("RUSTC_BOOTSTRAP", "1");
 +        builder.info("Dist src");
 +        let _time = timeit(builder);
-+        builder.run(&mut cmd);
++        builder.run(
++            &mut cmd,
++            crate::utils::exec::OutputMode::Print,
++            crate::utils::exec::OutputMode::Print,
++        );
 +
 +        builder.remove(&temp_lock);
 +
@@ -48,10 +52,10 @@ index 012d64e5344..aedb53358ef 100644
      }
  }
 diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
-index 5ed6b357e20..ad617948c4b 100644
+index 453fb39327d..af579af9eca 100644
 --- a/src/bootstrap/src/lib.rs
 +++ b/src/bootstrap/src/lib.rs
-@@ -1649,6 +1649,30 @@ fn read_stamp_file(&self, stamp: &Path) -> Vec<(PathBuf, DependencyType)> {
+@@ -1732,6 +1732,30 @@ fn read_stamp_file(&self, stamp: &Path) -> Vec<(PathBuf, DependencyType)> {
          paths
      }
  
@@ -65,7 +69,7 @@ index 5ed6b357e20..ad617948c4b 100644
 +        if src == dst {
 +            return;
 +        }
-+        let _ = fs::remove_file(&dst);
++        let _ = fs::remove_file(dst);
 +        let metadata = t!(src.symlink_metadata());
 +        if let Err(e) = fs::copy(src, dst) {
 +            panic!("failed to copy `{}` to `{}`: {}", src.display(), dst.display(), e)

build/moz.configure/toolchain.configure

@@ -2052,11 +2052,7 @@ def select_linker_tmpl(host_or_target):
             and (
                 (
                     target.kernel != "Darwin"
-                    and (
+                    and (developer_options or c_compiler.version >= "15.0")
-                        developer_options
-                        or host_or_target_str == "host"
-                        or c_compiler.version >= "15.0"
-                    )
                 )
                 or (
                     target.kernel == "Darwin"

docs/writing-rust-code/update-policy.md

@@ -164,7 +164,7 @@ Here are the Rust versions for each Firefox version.
 | Firefox 135 | Rust 1.83.0 | 1.76.0 | 2024 November 28 | 2025 January 2 | 2025 February 4
 | Firefox 136 | Rust 1.84.0 | 1.76.0 | 2025 January 9 | 2025 January 30 | 2025 March 4
 | **Estimated** |
-| Firefox 137 | Rust 1.85.0 | ? | 2025 February 20 | 2025 February 27 | 2025 April 1
+| Firefox 137 | Rust 1.85.0 | 1.82.0 | 2025 February 20 | 2025 February 27 | 2025 April 1
 | Firefox 138 | Rust 1.85.0 | ? | 2025 February 20 | 2025 March 27 | 2025 April 29
 | Firefox 139 | Rust 1.86.0 | ? | 2025 April 3 | 2025 April 24 | 2025 May 27
 | Firefox 140 | Rust 1.87.0 | ? | 2025 May 15 | 2025 May 22 | 2025 June 24

python/mozboot/mozboot/util.py

@@ -13,7 +13,7 @@ from mach.site import PythonVirtualenv
 from mach.util import get_state_dir
 
 # Keep in sync with rust-version in top-level Cargo.toml.
-MINIMUM_RUST_VERSION = "1.76.0"
+MINIMUM_RUST_VERSION = "1.82.0"
 
 
 def get_tools_dir(srcdir=False):

taskcluster/kinds/fetch/toolchains.yml

@@ -386,7 +386,10 @@ rust-1.81.0:
         type: git
         include-dot-git: true
         repo: https://github.com/rust-lang/rust/
-        revision: eeb90cda1969383f56a2637cbd3037bdf598841c
+        # NOTE: This is 1.81.0 and then some, to accommodate compiling some 1.82.0 code without
+        # breaking patches we use for sanitizers. See
+        # <https://bugzilla.mozilla.org/show_bug.cgi?id=1915537> for follow-up.
+        revision: ab1527f1d6560168f9fd36fa8cd7ba677c1d36ad
 
 rust-nightly:
     description: Rust nightly source code

taskcluster/kinds/toolchain/rust.yml

@@ -11,12 +11,12 @@ task-defaults:
         script: repack_rust.py
         toolchain-artifact: public/build/rustc.tar.zst
 
-linux64-rust-1.76:
+linux64-rust-1.82:
     treeherder:
-        symbol: TL(rust-1.76)
+        symbol: TL(rust-1.82)
     run:
         arguments: [
-            '--channel', '1.76.0',
+            '--channel', '1.82.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'i686-unknown-linux-gnu',
@@ -110,6 +110,7 @@ linux64-rust-1.81-dev:
             RUSTFLAGS_NOT_BOOTSTRAP: '-Clink-arg=-Wl,--undefined-version'
     run:
         arguments: [
+            '--patch', 'rust-compiler-intrinsics.patch',
             '--patch', 'rust-vendor-std.patch',
             '--patch', 'src/tools/cargo:cargo-vendor-std-1.79.patch',
             '--channel', 'dev',
@@ -117,6 +118,7 @@ linux64-rust-1.81-dev:
             '--target', 'x86_64-unknown-linux-gnu',
         ]
         resources:
+            - build/build-rust/rust-compiler-intrinsics.patch
             - build/build-rust/rust-vendor-std.patch
             - build/build-rust/cargo-vendor-std-1.79.patch
         toolchain-alias: