Merging upstream version 1.69.0+dfsg1.

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

16 files changed, 1120 insertions, 431 deletions

diff --git a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
index 43a449b3a..adb98d7eb 100644
--- a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
@@ -28,5 +28,5 @@ ENV \
 
 ENV HOSTS=s390x-unknown-linux-gnu
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --enable-lld --enable-profiler --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --enable-lld --enable-sanitizers --enable-profiler --disable-docs
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
index 6bdc88e18..5feba4e06 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
@@ -81,7 +81,7 @@ ENV RUST_CONFIGURE_ARGS \
       --set rust.jemalloc \
       --set rust.use-lld=true \
       --set rust.lto=thin
-ENV SCRIPT ../src/ci/pgo.sh python3 ../x.py dist \
+ENV SCRIPT python3 ../src/ci/stage-build.py python3 ../x.py dist \
     --host $HOSTS --target $HOSTS \
     --include-default-paths \
     build-manifest bootstrap
diff --git a/src/ci/docker/host-x86_64/mingw-check/Dockerfile b/src/ci/docker/host-x86_64/mingw-check/Dockerfile
index 4cc5d9f8a..98bd90210 100644
--- a/src/ci/docker/host-x86_64/mingw-check/Dockerfile
+++ b/src/ci/docker/host-x86_64/mingw-check/Dockerfile
@@ -23,6 +23,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 RUN curl -sL https://nodejs.org/dist/v16.9.0/node-v16.9.0-linux-x64.tar.xz | tar -xJ
 ENV PATH="/node-v16.9.0-linux-x64/bin:${PATH}"
+ENV RUST_CONFIGURE_ARGS="--set rust.validate-mir-opts=3"
+
 # Install es-check
 # Pin its version to prevent unrelated CI failures due to future es-check versions.
 RUN npm install es-check@6.1.1 eslint@8.6.0 -g
@@ -38,7 +40,7 @@ COPY host-x86_64/mingw-check/validate-error-codes.sh /scripts/
 
 ENV RUN_CHECK_WITH_PARALLEL_QUERIES 1
 ENV SCRIPT python3 ../x.py --stage 2 test src/tools/expand-yaml-anchors && \
-           python3 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu --all-targets && \
+           python3 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu && \
            python3 ../x.py build --stage 0 src/tools/build-manifest && \
            python3 ../x.py test --stage 0 src/tools/compiletest && \
            python3 ../x.py test --stage 0 core alloc std test proc_macro && \
diff --git a/src/ci/docker/host-x86_64/mingw-check/validate-toolstate.sh b/src/ci/docker/host-x86_64/mingw-check/validate-toolstate.sh
index c6d728eb8..0b06f5e36 100755
--- a/src/ci/docker/host-x86_64/mingw-check/validate-toolstate.sh
+++ b/src/ci/docker/host-x86_64/mingw-check/validate-toolstate.sh
@@ -9,11 +9,5 @@ git clone --depth=1 https://github.com/rust-lang-nursery/rust-toolstate.git
 cd rust-toolstate
 python3 "../../src/tools/publish_toolstate.py" "$(git rev-parse HEAD)" \
     "$(git log --format=%s -n1 HEAD)" "" ""
-# Only check maintainers if this build is supposed to publish toolstate.
-# Builds that are not supposed to publish don't have the access token.
-if [ -n "${TOOLSTATE_PUBLISH+is_set}" ]; then
-  TOOLSTATE_VALIDATE_MAINTAINERS_REPO=rust-lang/rust python3 \
-      "../../src/tools/publish_toolstate.py"
-fi
 cd ..
 rm -rf rust-toolstate
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-13-stage1/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-13-stage1/Dockerfile
deleted file mode 100644
index bcbf58253..000000000
--- a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-13-stage1/Dockerfile
+++ /dev/null
@@ -1,49 +0,0 @@
-FROM ubuntu:22.04
-
-ARG DEBIAN_FRONTEND=noninteractive
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    g++ \
-    gcc-multilib \
-    make \
-    ninja-build \
-    file \
-    curl \
-    ca-certificates \
-    python2.7 \
-    git \
-    cmake \
-    sudo \
-    gdb \
-    llvm-13-tools \
-    llvm-13-dev \
-    libedit-dev \
-    libssl-dev \
-    pkg-config \
-    zlib1g-dev \
-    xz-utils \
-    nodejs \
-    && rm -rf /var/lib/apt/lists/*
-
-COPY scripts/sccache.sh /scripts/
-RUN sh /scripts/sccache.sh
-
-# We are disabling CI LLVM since this builder is intentionally using a host
-# LLVM, rather than the typical src/llvm-project LLVM.
-ENV NO_DOWNLOAD_CI_LLVM 1
-
-# Using llvm-link-shared due to libffi issues -- see #34486
-ENV RUST_CONFIGURE_ARGS \
-    --build=x86_64-unknown-linux-gnu \
-    --llvm-root=/usr/lib/llvm-13 \
-    --enable-llvm-link-shared \
-    --set rust.thin-lto-import-instr-limit=10
-
-ENV SCRIPT python2.7 ../x.py --stage 1 test --exclude src/tools/tidy && \
-    # Run the `mir-opt` tests again but this time for a 32-bit target.
-    # This enforces that tests using `// EMIT_MIR_FOR_EACH_BIT_WIDTH` have
-    # both 32-bit and 64-bit outputs updated by the PR author, before
-    # the PR is approved and tested for merging.
-    # It will also detect tests lacking `// EMIT_MIR_FOR_EACH_BIT_WIDTH`,
-    # despite having different output on 32-bit vs 64-bit targets.
-    python2.7 ../x.py --stage 1 test tests/mir-opt \
-    --host='' --target=i686-unknown-linux-gnu
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-14-stage1/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-14-stage1/Dockerfile
new file mode 100644
index 000000000..b99a0886b
--- /dev/null
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-14-stage1/Dockerfile
@@ -0,0 +1,49 @@
+FROM ubuntu:22.04
+
+ARG DEBIAN_FRONTEND=noninteractive
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  g++ \
+  gcc-multilib \
+  make \
+  ninja-build \
+  file \
+  curl \
+  ca-certificates \
+  python3 \
+  git \
+  cmake \
+  sudo \
+  gdb \
+  llvm-14-tools \
+  llvm-14-dev \
+  libedit-dev \
+  libssl-dev \
+  pkg-config \
+  zlib1g-dev \
+  xz-utils \
+  nodejs \
+  && rm -rf /var/lib/apt/lists/*
+
+COPY scripts/sccache.sh /scripts/
+RUN sh /scripts/sccache.sh
+
+# We are disabling CI LLVM since this builder is intentionally using a host
+# LLVM, rather than the typical src/llvm-project LLVM.
+ENV NO_DOWNLOAD_CI_LLVM 1
+
+# Using llvm-link-shared due to libffi issues -- see #34486
+ENV RUST_CONFIGURE_ARGS \
+      --build=x86_64-unknown-linux-gnu \
+      --llvm-root=/usr/lib/llvm-14 \
+      --enable-llvm-link-shared \
+      --set rust.thin-lto-import-instr-limit=10
+
+ENV SCRIPT ../x.py --stage 1 test --exclude src/tools/tidy && \
+           # Run the `mir-opt` tests again but this time for a 32-bit target.
+           # This enforces that tests using `// EMIT_MIR_FOR_EACH_BIT_WIDTH` have
+           # both 32-bit and 64-bit outputs updated by the PR author, before
+           # the PR is approved and tested for merging.
+           # It will also detect tests lacking `// EMIT_MIR_FOR_EACH_BIT_WIDTH`,
+           # despite having different output on 32-bit vs 64-bit targets.
+           ../x.py --stage 1 test tests/mir-opt \
+                             --host='' --target=i686-unknown-linux-gnu
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-13/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-14/Dockerfile
index 9fc9e9cbf..db6032f87 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-13/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-14/Dockerfile
@@ -12,27 +12,25 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   curl \
   ca-certificates \
   python2.7 \
-  python3.9 \
+  python3 \
   git \
   cmake \
   sudo \
   gdb \
-  llvm-13-tools \
-  llvm-13-dev \
+  llvm-14-tools \
+  llvm-14-dev \
   libedit-dev \
   libssl-dev \
   pkg-config \
   zlib1g-dev \
   xz-utils \
   nodejs \
-  \
-# Install powershell so we can test x.ps1 on Linux
-    apt-transport-https software-properties-common && \
-    curl -s "https://packages.microsoft.com/config/ubuntu/$(lsb_release -rs)/packages-microsoft-prod.deb" > packages-microsoft-prod.deb && \
-    dpkg -i packages-microsoft-prod.deb && \
-    apt-get update && \
-    apt-get install -y powershell \
-    && rm -rf /var/lib/apt/lists/*
+  && rm -rf /var/lib/apt/lists/*
+
+# Install powershell (universal package) so we can test x.ps1 on Linux
+RUN curl -sL "https://github.com/PowerShell/PowerShell/releases/download/v7.3.1/powershell_7.3.1-1.deb_amd64.deb" > powershell.deb && \
+    dpkg -i powershell.deb && \
+    rm -f powershell.deb
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
@@ -44,7 +42,7 @@ ENV NO_DOWNLOAD_CI_LLVM 1
 # Using llvm-link-shared due to libffi issues -- see #34486
 ENV RUST_CONFIGURE_ARGS \
       --build=x86_64-unknown-linux-gnu \
-      --llvm-root=/usr/lib/llvm-13 \
+      --llvm-root=/usr/lib/llvm-14 \
       --enable-llvm-link-shared \
       --set rust.thin-lto-import-instr-limit=10
 
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-15/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-15/Dockerfile
new file mode 100644
index 000000000..5219247cc
--- /dev/null
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-15/Dockerfile
@@ -0,0 +1,67 @@
+FROM ubuntu:22.10
+
+ARG DEBIAN_FRONTEND=noninteractive
+
+# NOTE: intentionally installs both python2 and python3 so we can test support for both.
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  g++ \
+  gcc-multilib \
+  make \
+  ninja-build \
+  file \
+  curl \
+  ca-certificates \
+  python2.7 \
+  python3 \
+  git \
+  cmake \
+  sudo \
+  gdb \
+  llvm-15-tools \
+  llvm-15-dev \
+  libedit-dev \
+  libssl-dev \
+  pkg-config \
+  zlib1g-dev \
+  xz-utils \
+  nodejs \
+  && rm -rf /var/lib/apt/lists/*
+
+# Install powershell (universal package) so we can test x.ps1 on Linux
+RUN curl -sL "https://github.com/PowerShell/PowerShell/releases/download/v7.3.1/powershell_7.3.1-1.deb_amd64.deb" > powershell.deb && \
+    dpkg -i powershell.deb && \
+    rm -f powershell.deb
+
+COPY scripts/sccache.sh /scripts/
+RUN sh /scripts/sccache.sh
+
+# We are disabling CI LLVM since this builder is intentionally using a host
+# LLVM, rather than the typical src/llvm-project LLVM.
+ENV NO_DOWNLOAD_CI_LLVM 1
+
+# Using llvm-link-shared due to libffi issues -- see #34486
+ENV RUST_CONFIGURE_ARGS \
+      --build=x86_64-unknown-linux-gnu \
+      --llvm-root=/usr/lib/llvm-15 \
+      --enable-llvm-link-shared \
+      --set rust.thin-lto-import-instr-limit=10
+
+# NOTE: intentionally uses all of `x.py`, `x`, and `x.ps1` to make sure they all work on Linux.
+ENV SCRIPT ../x.py --stage 2 test --exclude src/tools/tidy && \
+           # Run the `mir-opt` tests again but this time for a 32-bit target.
+           # This enforces that tests using `// EMIT_MIR_FOR_EACH_BIT_WIDTH` have
+           # both 32-bit and 64-bit outputs updated by the PR author, before
+           # the PR is approved and tested for merging.
+           # It will also detect tests lacking `// EMIT_MIR_FOR_EACH_BIT_WIDTH`,
+           # despite having different output on 32-bit vs 64-bit targets.
+           ../x --stage 2 test tests/mir-opt \
+                             --host='' --target=i686-unknown-linux-gnu && \
+           # Run the UI test suite again, but in `--pass=check` mode
+           #
+           # This is intended to make sure that both `--pass=check` continues to
+           # work.
+           #
+           ../x.ps1 --stage 2 test tests/ui --pass=check \
+                             --host='' --target=i686-unknown-linux-gnu && \
+           # Run tidy at the very end, after all the other tests.
+           python2.7 ../x.py --stage 2 test src/tools/tidy
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version b/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version
index c39e9c5fb..9c550b2d7 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version
@@ -1 +1 @@
-0.14.1
\ No newline at end of file
+0.14.4
\ No newline at end of file
diff --git a/src/ci/docker/scripts/fuchsia-test-runner.py b/src/ci/docker/scripts/fuchsia-test-runner.py
index c8d1ff9ae..e7d1d9781 100755
--- a/src/ci/docker/scripts/fuchsia-test-runner.py
+++ b/src/ci/docker/scripts/fuchsia-test-runner.py
@@ -9,6 +9,7 @@ https://doc.rust-lang.org/stable/rustc/platform-support/fuchsia.html#aarch64-unk
 
 import argparse
 from dataclasses import dataclass
+import fcntl
 import glob
 import hashlib
 import json
@@ -19,18 +20,18 @@ import shutil
 import signal
 import subprocess
 import sys
-from typing import ClassVar, List
+from typing import ClassVar, List, Optional
 
 
 @dataclass
 class TestEnvironment:
     rust_dir: str
     sdk_dir: str
-    target_arch: str
-    package_server_pid: int = None
-    emu_addr: str = None
-    libstd_name: str = None
-    libtest_name: str = None
+    target: str
+    package_server_pid: Optional[int] = None
+    emu_addr: Optional[str] = None
+    libstd_name: Optional[str] = None
+    libtest_name: Optional[str] = None
     verbose: bool = False
 
     @staticmethod
@@ -40,6 +41,15 @@ class TestEnvironment:
             return os.path.abspath(tmp_dir)
         return os.path.join(os.path.dirname(__file__), "tmp~")
 
+    @staticmethod
+    def triple_to_arch(triple):
+        if "x86_64" in triple:
+            return "x64"
+        elif "aarch64" in triple:
+            return "arm64"
+        else:
+            raise Exception(f"Unrecognized target triple {triple}")
+
     @classmethod
     def env_file_path(cls):
         return os.path.join(cls.tmp_dir(), "test_env.json")
@@ -49,7 +59,7 @@ class TestEnvironment:
         return cls(
             os.path.abspath(args.rust),
             os.path.abspath(args.sdk),
-            args.target_arch,
+            args.target,
             verbose=args.verbose,
         )
 
@@ -60,7 +70,7 @@ class TestEnvironment:
             return cls(
                 test_env["rust_dir"],
                 test_env["sdk_dir"],
-                test_env["target_arch"],
+                test_env["target"],
                 libstd_name=test_env["libstd_name"],
                 libtest_name=test_env["libtest_name"],
                 emu_addr=test_env["emu_addr"],
@@ -68,13 +78,6 @@ class TestEnvironment:
                 verbose=test_env["verbose"],
             )
 
-    def image_name(self):
-        if self.target_arch == "x64":
-            return "qemu-x64"
-        if self.target_arch == "arm64":
-            return "qemu-arm64"
-        raise Exception(f"Unrecognized target architecture {self.target_arch}")
-
     def write_to_file(self):
         with open(self.env_file_path(), "w", encoding="utf-8") as f:
             f.write(json.dumps(self.__dict__))
@@ -108,13 +111,6 @@ class TestEnvironment:
     def repo_dir(self):
         return os.path.join(self.tmp_dir(), self.TEST_REPO_NAME)
 
-    def rustlib_dir(self):
-        if self.target_arch == "x64":
-            return "x86_64-unknown-fuchsia"
-        if self.target_arch == "arm64":
-            return "aarch64-unknown-fuchsia"
-        raise Exception(f"Unrecognized target architecture {self.target_arch}")
-
     def libs_dir(self):
         return os.path.join(
             self.rust_dir,
@@ -125,7 +121,7 @@ class TestEnvironment:
         return os.path.join(
             self.libs_dir(),
             "rustlib",
-            self.rustlib_dir(),
+            self.target,
             "lib",
         )
 
@@ -151,6 +147,9 @@ class TestEnvironment:
     def zxdb_script_path(self):
         return os.path.join(self.tmp_dir(), "zxdb_script")
 
+    def pm_lockfile_path(self):
+        return os.path.join(self.tmp_dir(), "pm.lock")
+
     def log_info(self, msg):
         print(msg)
 
@@ -384,7 +383,7 @@ class TestEnvironment:
                 "--emulator-log",
                 self.emulator_log_path(),
                 "--image-name",
-                self.image_name(),
+                "qemu-" + self.triple_to_arch(self.target),
             ],
             stdout=self.subprocess_output(),
             stderr=self.subprocess_output(),
@@ -465,6 +464,9 @@ class TestEnvironment:
             stderr=self.subprocess_output(),
         )
 
+        # Create lockfiles
+        open(self.pm_lockfile_path(), 'a').close()
+
         # Write to file
         self.write_to_file()
 
@@ -512,9 +514,8 @@ class TestEnvironment:
     bin/{exe_name}={bin_path}
     lib/{libstd_name}={rust_dir}/lib/rustlib/{rustlib_dir}/lib/{libstd_name}
     lib/{libtest_name}={rust_dir}/lib/rustlib/{rustlib_dir}/lib/{libtest_name}
-    lib/ld.so.1={sdk_dir}/arch/{target_arch}/sysroot/lib/libc.so
-    lib/libzircon.so={sdk_dir}/arch/{target_arch}/sysroot/lib/libzircon.so
-    lib/libfdio.so={sdk_dir}/arch/{target_arch}/lib/libfdio.so
+    lib/ld.so.1={sdk_dir}/arch/{target_arch}/sysroot/dist/lib/ld.so.1
+    lib/libfdio.so={sdk_dir}/arch/{target_arch}/dist/libfdio.so
     """
 
     TEST_ENV_VARS: ClassVar[List[str]] = [
@@ -642,11 +643,11 @@ class TestEnvironment:
                         package_dir=package_dir,
                         package_name=package_name,
                         rust_dir=self.rust_dir,
-                        rustlib_dir=self.rustlib_dir(),
+                        rustlib_dir=self.target,
                         sdk_dir=self.sdk_dir,
                         libstd_name=self.libstd_name,
                         libtest_name=self.libtest_name,
-                        target_arch=self.target_arch,
+                        target_arch=self.triple_to_arch(self.target),
                     )
                 )
                 for shared_lib in shared_libs:
@@ -682,19 +683,25 @@ class TestEnvironment:
             log("Publishing package to repo...")
 
             # Publish package to repo
-            subprocess.check_call(
-                [
-                    self.tool_path("pm"),
-                    "publish",
-                    "-a",
-                    "-repo",
-                    self.repo_dir(),
-                    "-f",
-                    far_path,
-                ],
-                stdout=log_file,
-                stderr=log_file,
-            )
+            with open(self.pm_lockfile_path(), 'w') as pm_lockfile:
+                fcntl.lockf(pm_lockfile.fileno(), fcntl.LOCK_EX)
+                subprocess.check_call(
+                    [
+                        self.tool_path("pm"),
+                        "publish",
+                        "-a",
+                        "-repo",
+                        self.repo_dir(),
+                        "-f",
+                        far_path,
+                    ],
+                    stdout=log_file,
+                    stderr=log_file,
+                )
+                # This lock should be released automatically when the pm
+                # lockfile is closed, but we'll be polite and unlock it now
+                # since the spec leaves some wiggle room.
+                fcntl.lockf(pm_lockfile.fileno(), fcntl.LOCK_UN)
 
             log("Running ffx test...")
 
@@ -849,23 +856,34 @@ class TestEnvironment:
             "--",
             "--build-id-dir",
             os.path.join(self.sdk_dir, ".build-id"),
-            "--build-id-dir",
-            os.path.join(self.libs_dir(), ".build-id"),
         ]
 
-        # Add rust source if it's available
-        if args.rust_src is not None:
+        libs_build_id_path = os.path.join(self.libs_dir(), ".build-id")
+        if os.path.exists(libs_build_id_path):
+            # Add .build-id symbols if installed libs have been stripped into a
+            # .build-id directory
             command += [
-                "--build-dir",
-                args.rust_src,
+                "--build-id-dir",
+                libs_build_id_path,
+            ]
+        else:
+            # If no .build-id directory is detected, then assume that the shared
+            # libs contain their debug symbols
+            command += [
+                f"--symbol-path={self.rust_dir}/lib/rustlib/{self.target}/lib",
             ]
 
+        # Add rust source if it's available
+        rust_src_map = None
+        if args.rust_src is not None:
+            # This matches the remapped prefix used by compiletest. There's no
+            # clear way that we can determine this, so it's hard coded.
+            rust_src_map = f"/rustc/FAKE_PREFIX={args.rust_src}"
+
         # Add fuchsia source if it's available
+        fuchsia_src_map = None
         if args.fuchsia_src is not None:
-            command += [
-                "--build-dir",
-                os.path.join(args.fuchsia_src, "out", "default"),
-            ]
+            fuchsia_src_map = f"./../..={args.fuchsia_src}"
 
         # Load debug symbols for the test binary and automatically attach
         if args.test is not None:
@@ -888,7 +906,28 @@ class TestEnvironment:
                 test_name,
             )
 
+            # The fake-test-src-base directory maps to the suite directory
+            # e.g. tests/ui/foo.rs has a path of rust/fake-test-src-base/foo.rs
+            fake_test_src_base = os.path.join(
+                args.rust_src,
+                "fake-test-src-base",
+            )
+            real_test_src_base = os.path.join(
+                args.rust_src,
+                "tests",
+                args.test.split(os.path.sep)[0],
+            )
+            test_src_map = f"{fake_test_src_base}={real_test_src_base}"
+
             with open(self.zxdb_script_path(), mode="w", encoding="utf-8") as f:
+                print(f"set source-map += {test_src_map}", file=f)
+
+                if rust_src_map is not None:
+                    print(f"set source-map += {rust_src_map}", file=f)
+
+                if fuchsia_src_map is not None:
+                    print(f"set source-map += {fuchsia_src_map}", file=f)
+
                 print(f"attach {test_name[:31]}", file=f)
 
             command += [
@@ -905,6 +944,20 @@ class TestEnvironment:
         # Connect to the running emulator with zxdb
         subprocess.run(command, env=self.ffx_cmd_env(), check=False)
 
+    def syslog(self, args):
+        subprocess.run(
+            [
+                self.tool_path("ffx"),
+                "--config",
+                self.ffx_user_config_path(),
+                "log",
+                "--since",
+                "now",
+            ],
+            env=self.ffx_cmd_env(),
+            check=False,
+        )
+
 
 def start(args):
     test_env = TestEnvironment.from_args(args)
@@ -938,6 +991,12 @@ def debug(args):
     return 0
 
 
+def syslog(args):
+    test_env = TestEnvironment.read_from_file()
+    test_env.syslog(args)
+    return 0
+
+
 def main():
     parser = argparse.ArgumentParser()
 
@@ -969,8 +1028,8 @@ def main():
         action="store_true",
     )
     start_parser.add_argument(
-        "--target-arch",
-        help="the architecture of the image to test",
+        "--target",
+        help="the target platform to test",
         required=True,
     )
     start_parser.set_defaults(func=start)
@@ -1033,6 +1092,11 @@ def main():
     )
     debug_parser.set_defaults(func=debug)
 
+    syslog_parser = subparsers.add_parser(
+        "syslog", help="prints the device syslog"
+    )
+    syslog_parser.set_defaults(func=syslog)
+
     args = parser.parse_args()
     return args.func(args)
 
diff --git a/src/ci/github-actions/ci.yml b/src/ci/github-actions/ci.yml
index 743b57ed4..c594288dc 100644
--- a/src/ci/github-actions/ci.yml
+++ b/src/ci/github-actions/ci.yml
@@ -33,6 +33,7 @@ x--expand-yaml-anchors--remove:
 
   - &shared-ci-variables
     CI_JOB_NAME: ${{ matrix.name }}
+    CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse
 
   - &public-variables
     SCCACHE_BUCKET: rust-lang-ci-sccache2
@@ -73,15 +74,15 @@ x--expand-yaml-anchors--remove:
     env: {}
 
   - &job-linux-xl
-    os: ubuntu-20.04-xl
+    os: ubuntu-20.04-16core-64gb
     <<: *base-job
 
   - &job-macos-xl
-    os: macos-latest  # We don't have an XL builder for this
+    os: macos-12-xl
     <<: *base-job
 
   - &job-windows-xl
-    os: windows-latest-xl
+    os: windows-2019-8core-32gb
     <<: *base-job
 
   - &job-aarch64-linux
@@ -299,15 +300,13 @@ jobs:
             <<: *job-linux-xl
             tidy: true
 
-          - name: x86_64-gnu-llvm-13
+          - name: x86_64-gnu-llvm-14
             <<: *job-linux-xl
             tidy: false
 
           - name: x86_64-gnu-tools
             <<: *job-linux-xl
             tidy: false
-            env:
-              CI_ONLY_WHEN_SUBMODULES_CHANGED: 1
 
   auto:
     permissions:
@@ -450,12 +449,17 @@ jobs:
           - name: x86_64-gnu-distcheck
             <<: *job-linux-xl
 
-          - name: x86_64-gnu-llvm-13
+          - name: x86_64-gnu-llvm-15
+            env:
+              RUST_BACKTRACE: 1
+            <<: *job-linux-xl
+
+          - name: x86_64-gnu-llvm-14
             env:
               RUST_BACKTRACE: 1
             <<: *job-linux-xl
 
-          - name: x86_64-gnu-llvm-13-stage1
+          - name: x86_64-gnu-llvm-14-stage1
             env:
               RUST_BACKTRACE: 1
             <<: *job-linux-xl
@@ -619,9 +623,7 @@ jobs:
 
           - name: i686-mingw-1
             env:
-              RUST_CONFIGURE_ARGS: >-
-                --build=i686-pc-windows-gnu
-                --set llvm.allow-old-toolchain
+              RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
               SCRIPT: make ci-mingw-subset-1
               # We are intentionally allowing an old toolchain on this builder (and that's
               # incompatible with LLVM downloads today).
@@ -631,9 +633,7 @@ jobs:
 
           - name: i686-mingw-2
             env:
-              RUST_CONFIGURE_ARGS: >-
-                --build=i686-pc-windows-gnu
-                --set llvm.allow-old-toolchain
+              RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
               SCRIPT: make ci-mingw-subset-2
               # We are intentionally allowing an old toolchain on this builder (and that's
               # incompatible with LLVM downloads today).
@@ -647,7 +647,6 @@ jobs:
               RUST_CONFIGURE_ARGS: >-
                 --build=x86_64-pc-windows-gnu
                 --enable-profiler
-                --set llvm.allow-old-toolchain
               # We are intentionally allowing an old toolchain on this builder (and that's
               # incompatible with LLVM downloads today).
               NO_DOWNLOAD_CI_LLVM: 1
@@ -660,7 +659,6 @@ jobs:
               RUST_CONFIGURE_ARGS: >-
                 --build=x86_64-pc-windows-gnu
                 --enable-profiler
-                --set llvm.allow-old-toolchain
               # We are intentionally allowing an old toolchain on this builder (and that's
               # incompatible with LLVM downloads today).
               NO_DOWNLOAD_CI_LLVM: 1
@@ -675,7 +673,7 @@ jobs:
                 --target=x86_64-pc-windows-msvc
                 --enable-full-tools
                 --enable-profiler
-              SCRIPT: PGO_HOST=x86_64-pc-windows-msvc src/ci/pgo.sh python x.py dist bootstrap --include-default-paths
+              SCRIPT: PGO_HOST=x86_64-pc-windows-msvc python src/ci/stage-build.py python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
             <<: *job-windows-xl
 
@@ -711,7 +709,6 @@ jobs:
                 --build=i686-pc-windows-gnu
                 --enable-full-tools
                 --enable-profiler
-                --set llvm.allow-old-toolchain
               # We are intentionally allowing an old toolchain on this builder (and that's
               # incompatible with LLVM downloads today).
               NO_DOWNLOAD_CI_LLVM: 1
@@ -727,7 +724,6 @@ jobs:
                 --build=x86_64-pc-windows-gnu
                 --enable-full-tools
                 --enable-profiler
-                --set llvm.allow-old-toolchain
               # We are intentionally allowing an old toolchain on this builder (and that's
               # incompatible with LLVM downloads today).
               NO_DOWNLOAD_CI_LLVM: 1
diff --git a/src/ci/pgo.sh b/src/ci/pgo.sh
deleted file mode 100755
index cbe32920a..000000000
--- a/src/ci/pgo.sh
+++ /dev/null
@@ -1,230 +0,0 @@
-#!/bin/bash
-# ignore-tidy-linelength
-
-set -euxo pipefail
-
-ci_dir=`cd $(dirname $0) && pwd`
-source "$ci_dir/shared.sh"
-
-# The root checkout, where the source is located
-CHECKOUT=/checkout
-
-DOWNLOADED_LLVM=/rustroot
-
-# The main directory where the build occurs, which can be different between linux and windows
-BUILD_ROOT=$CHECKOUT/obj
-
-if isWindows; then
-    CHECKOUT=$(pwd)
-    DOWNLOADED_LLVM=$CHECKOUT/citools/clang-rust
-    BUILD_ROOT=$CHECKOUT
-fi
-
-# The various build artifacts used in other commands: to launch rustc builds, build the perf
-# collector, and run benchmarks to gather profiling data
-BUILD_ARTIFACTS=$BUILD_ROOT/build/$PGO_HOST
-RUSTC_STAGE_0=$BUILD_ARTIFACTS/stage0/bin/rustc
-CARGO_STAGE_0=$BUILD_ARTIFACTS/stage0/bin/cargo
-RUSTC_STAGE_2=$BUILD_ARTIFACTS/stage2/bin/rustc
-
-# Windows needs these to have the .exe extension
-if isWindows; then
-    RUSTC_STAGE_0="${RUSTC_STAGE_0}.exe"
-    CARGO_STAGE_0="${CARGO_STAGE_0}.exe"
-    RUSTC_STAGE_2="${RUSTC_STAGE_2}.exe"
-fi
-
-# Make sure we have a temporary PGO work folder
-PGO_TMP=/tmp/tmp-pgo
-mkdir -p $PGO_TMP
-rm -rf $PGO_TMP/*
-
-RUSTC_PERF=$PGO_TMP/rustc-perf
-
-# Compile several crates to gather execution PGO profiles.
-# Arg0 => profiles (Debug, Opt)
-# Arg1 => scenarios (Full, IncrFull, All)
-# Arg2 => crates (syn, cargo, ...)
-gather_profiles () {
-  cd $BUILD_ROOT
-
-  # Compile libcore, both in opt-level=0 and opt-level=3
-  RUSTC_BOOTSTRAP=1 $RUSTC_STAGE_2 \
-      --edition=2021 --crate-type=lib $CHECKOUT/library/core/src/lib.rs \
-      --out-dir $PGO_TMP
-  RUSTC_BOOTSTRAP=1 $RUSTC_STAGE_2 \
-      --edition=2021 --crate-type=lib -Copt-level=3 $CHECKOUT/library/core/src/lib.rs \
-      --out-dir $PGO_TMP
-
-  cd $RUSTC_PERF
-
-  # Run rustc-perf benchmarks
-  # Benchmark using profile_local with eprintln, which essentially just means
-  # don't actually benchmark -- just make sure we run rustc a bunch of times.
-  RUST_LOG=collector=debug \
-  RUSTC=$RUSTC_STAGE_0 \
-  RUSTC_BOOTSTRAP=1 \
-  $CARGO_STAGE_0 run -p collector --bin collector -- \
-      profile_local \
-      eprintln \
-      $RUSTC_STAGE_2 \
-      --id Test \
-      --profiles $1 \
-      --cargo $CARGO_STAGE_0 \
-      --scenarios $2 \
-      --include $3
-
-  cd $BUILD_ROOT
-}
-
-# This path has to be absolute
-LLVM_PROFILE_DIRECTORY_ROOT=$PGO_TMP/llvm-pgo
-
-# We collect LLVM profiling information and rustc profiling information in
-# separate phases. This increases build time -- though not by a huge amount --
-# but prevents any problems from arising due to different profiling runtimes
-# being simultaneously linked in.
-# LLVM IR PGO does not respect LLVM_PROFILE_FILE, so we have to set the profiling file
-# path through our custom environment variable. We include the PID in the directory path
-# to avoid updates to profile files being lost because of race conditions.
-LLVM_PROFILE_DIR=${LLVM_PROFILE_DIRECTORY_ROOT}/prof-%p python3 $CHECKOUT/x.py build \
-    --target=$PGO_HOST \
-    --host=$PGO_HOST \
-    --stage 2 library/std \
-    --llvm-profile-generate
-
-# Compile rustc-perf:
-# - get the expected commit source code: on linux, the Dockerfile downloads a source archive before
-# running this script. On Windows, we do that here.
-if isLinux; then
-    cp -r /tmp/rustc-perf $RUSTC_PERF
-    chown -R $(whoami): $RUSTC_PERF
-else
-    # rustc-perf version from 2022-07-22
-    PERF_COMMIT=3c253134664fdcba862c539d37f0de18557a9a4c
-    retry curl -LS -o $PGO_TMP/perf.zip \
-        https://github.com/rust-lang/rustc-perf/archive/$PERF_COMMIT.zip && \
-        cd $PGO_TMP && unzip -q perf.zip && \
-        mv rustc-perf-$PERF_COMMIT $RUSTC_PERF && \
-        rm perf.zip
-fi
-
-# - build rustc-perf's collector ahead of time, which is needed to make sure the rustc-fake binary
-# used by the collector is present.
-cd $RUSTC_PERF
-
-RUSTC=$RUSTC_STAGE_0 \
-RUSTC_BOOTSTRAP=1 \
-$CARGO_STAGE_0 build -p collector
-
-# Here we're profiling LLVM, so we only care about `Debug` and `Opt`, because we want to stress
-# codegen. We also profile some of the most prolific crates.
-gather_profiles "Debug,Opt" "Full" \
-    "syn-1.0.89,cargo-0.60.0,serde-1.0.136,ripgrep-13.0.0,regex-1.5.5,clap-3.1.6,hyper-0.14.18"
-
-LLVM_PROFILE_MERGED_FILE=$PGO_TMP/llvm-pgo.profdata
-
-# Merge the profile data we gathered for LLVM
-# Note that this uses the profdata from the clang we used to build LLVM,
-# which likely has a different version than our in-tree clang.
-$DOWNLOADED_LLVM/bin/llvm-profdata merge -o ${LLVM_PROFILE_MERGED_FILE} ${LLVM_PROFILE_DIRECTORY_ROOT}
-
-echo "LLVM PGO statistics"
-du -sh ${LLVM_PROFILE_MERGED_FILE}
-du -sh ${LLVM_PROFILE_DIRECTORY_ROOT}
-echo "Profile file count"
-find ${LLVM_PROFILE_DIRECTORY_ROOT} -type f | wc -l
-
-# We don't need the individual .profraw files now that they have been merged into a final .profdata
-rm -r $LLVM_PROFILE_DIRECTORY_ROOT
-
-# Rustbuild currently doesn't support rebuilding LLVM when PGO options
-# change (or any other llvm-related options); so just clear out the relevant
-# directories ourselves.
-rm -r $BUILD_ARTIFACTS/llvm $BUILD_ARTIFACTS/lld
-
-# Okay, LLVM profiling is done, switch to rustc PGO.
-
-# The path has to be absolute
-RUSTC_PROFILE_DIRECTORY_ROOT=$PGO_TMP/rustc-pgo
-
-python3 $CHECKOUT/x.py build --target=$PGO_HOST --host=$PGO_HOST \
-    --stage 2 library/std \
-    --rust-profile-generate=${RUSTC_PROFILE_DIRECTORY_ROOT}
-
-# Here we're profiling the `rustc` frontend, so we also include `Check`.
-# The benchmark set includes various stress tests that put the frontend under pressure.
-if isLinux; then
-    # The profile data is written into a single filepath that is being repeatedly merged when each
-    # rustc invocation ends. Empirically, this can result in some profiling data being lost. That's
-    # why we override the profile path to include the PID. This will produce many more profiling
-    # files, but the resulting profile will produce a slightly faster rustc binary.
-    LLVM_PROFILE_FILE=${RUSTC_PROFILE_DIRECTORY_ROOT}/default_%m_%p.profraw gather_profiles \
-        "Check,Debug,Opt" "All" \
-        "externs,ctfe-stress-5,cargo-0.60.0,token-stream-stress,match-stress,tuple-stress,diesel-1.4.8,bitmaps-3.1.0"
-else
-    # On windows, we don't do that yet (because it generates a lot of data, hitting disk space
-    # limits on the builder), and use the default profraw merging behavior.
-    gather_profiles \
-        "Check,Debug,Opt" "All" \
-        "externs,ctfe-stress-5,cargo-0.60.0,token-stream-stress,match-stress,tuple-stress,diesel-1.4.8,bitmaps-3.1.0"
-fi
-
-RUSTC_PROFILE_MERGED_FILE=$PGO_TMP/rustc-pgo.profdata
-
-# Merge the profile data we gathered
-$BUILD_ARTIFACTS/llvm/bin/llvm-profdata \
-    merge -o ${RUSTC_PROFILE_MERGED_FILE} ${RUSTC_PROFILE_DIRECTORY_ROOT}
-
-echo "Rustc PGO statistics"
-du -sh ${RUSTC_PROFILE_MERGED_FILE}
-du -sh ${RUSTC_PROFILE_DIRECTORY_ROOT}
-echo "Profile file count"
-find ${RUSTC_PROFILE_DIRECTORY_ROOT} -type f | wc -l
-
-# We don't need the individual .profraw files now that they have been merged into a final .profdata
-rm -r $RUSTC_PROFILE_DIRECTORY_ROOT
-
-# Rustbuild currently doesn't support rebuilding LLVM when PGO options
-# change (or any other llvm-related options); so just clear out the relevant
-# directories ourselves.
-rm -r $BUILD_ARTIFACTS/llvm $BUILD_ARTIFACTS/lld
-
-if isLinux; then
-  # Gather BOLT profile (BOLT is currently only available on Linux)
-  python3 ../x.py build --target=$PGO_HOST --host=$PGO_HOST \
-      --stage 2 library/std \
-      --llvm-profile-use=${LLVM_PROFILE_MERGED_FILE} \
-      --llvm-bolt-profile-generate
-
-  BOLT_PROFILE_MERGED_FILE=/tmp/bolt.profdata
-
-  # Here we're profiling Bolt.
-  gather_profiles "Check,Debug,Opt" "Full" \
-  "syn-1.0.89,serde-1.0.136,ripgrep-13.0.0,regex-1.5.5,clap-3.1.6,hyper-0.14.18"
-
-  merge-fdata /tmp/prof.fdata* > ${BOLT_PROFILE_MERGED_FILE}
-
-  echo "BOLT statistics"
-  du -sh /tmp/prof.fdata*
-  du -sh ${BOLT_PROFILE_MERGED_FILE}
-  echo "Profile file count"
-  find /tmp/prof.fdata* -type f | wc -l
-
-  rm -r $BUILD_ARTIFACTS/llvm $BUILD_ARTIFACTS/lld
-
-  # This produces the actual final set of artifacts, using both the LLVM and rustc
-  # collected profiling data.
-  $@ \
-      --rust-profile-use=${RUSTC_PROFILE_MERGED_FILE} \
-      --llvm-profile-use=${LLVM_PROFILE_MERGED_FILE} \
-      --llvm-bolt-profile-use=${BOLT_PROFILE_MERGED_FILE}
-else
-  $@ \
-      --rust-profile-use=${RUSTC_PROFILE_MERGED_FILE} \
-      --llvm-profile-use=${LLVM_PROFILE_MERGED_FILE}
-fi
-
-echo "Rustc binary size"
-ls -la ./build/$PGO_HOST/stage2/bin
-ls -la ./build/$PGO_HOST/stage2/lib
diff --git a/src/ci/run.sh b/src/ci/run.sh
index 0db9c993e..efeb850cd 100755
--- a/src/ci/run.sh
+++ b/src/ci/run.sh
@@ -45,6 +45,8 @@ fi
 ci_dir=`cd $(dirname $0) && pwd`
 source "$ci_dir/shared.sh"
 
+export CARGO_REGISTRIES_CRATES_IO_PROTOCOL=sparse
+
 if ! isCI || isCiBranch auto || isCiBranch beta || isCiBranch try || isCiBranch try-perf; then
     RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set build.print-step-timings --enable-verbose-tests"
     RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set build.metrics"
@@ -57,6 +59,14 @@ RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-locked-deps"
 RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-cargo-native-static"
 RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set rust.codegen-units-std=1"
 
+# When building for mingw, limit the number of parallel linker jobs during
+# the LLVM build, as not to run out of memory.
+# This is an attempt to fix the spurious build error tracked by
+# https://github.com/rust-lang/rust/issues/108227.
+if isWindows && [[ ${CUSTOM_MINGW-0} -eq 1 ]]; then
+    RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set llvm.link-jobs=1"
+fi
+
 # Only produce xz tarballs on CI. gz tarballs will be generated by the release
 # process by recompressing the existing xz ones. This decreases the storage
 # space required for CI artifacts.
diff --git a/src/ci/scripts/install-mingw.sh b/src/ci/scripts/install-mingw.sh
index 1685fbbbb..7eccb9b86 100755
--- a/src/ci/scripts/install-mingw.sh
+++ b/src/ci/scripts/install-mingw.sh
@@ -2,24 +2,6 @@
 # If we need to download a custom MinGW, do so here and set the path
 # appropriately.
 #
-# Here we also do a pretty heinous thing which is to mangle the MinGW
-# installation we just downloaded. Currently, as of this writing, we're using
-# MinGW-w64 builds of gcc, and that's currently at 6.3.0. We use 6.3.0 as it
-# appears to be the first version which contains a fix for #40546, builds
-# randomly failing during LLVM due to ar.exe/ranlib.exe failures.
-#
-# Unfortunately, though, 6.3.0 *also* is the first version of MinGW-w64 builds
-# to contain a regression in gdb (#40184). As a result if we were to use the
-# gdb provided (7.11.1) then we would fail all debuginfo tests.
-#
-# In order to fix spurious failures (pretty high priority) we use 6.3.0. To
-# avoid disabling gdb tests we download an *old* version of gdb, specifically
-# that found inside the 6.2.0 distribution. We then overwrite the 6.3.0 gdb
-# with the 6.2.0 gdb to get tests passing.
-#
-# Note that we don't literally overwrite the gdb.exe binary because it appears
-# to just use gdborig.exe, so that's the binary we deal with instead.
-#
 # Otherwise install MinGW through `pacman`
 
 set -euo pipefail
@@ -27,8 +9,8 @@ IFS=$'\n\t'
 
 source "$(cd "$(dirname "$0")" && pwd)/../shared.sh"
 
-MINGW_ARCHIVE_32="i686-6.3.0-release-posix-dwarf-rt_v5-rev2.7z"
-MINGW_ARCHIVE_64="x86_64-6.3.0-release-posix-seh-rt_v5-rev2.7z"
+MINGW_ARCHIVE_32="i686-12.2.0-release-posix-dwarf-rt_v10-rev0.7z"
+MINGW_ARCHIVE_64="x86_64-12.2.0-release-posix-seh-rt_v10-rev0.7z"
 
 if isWindows; then
     case "${CI_JOB_NAME}" in
@@ -66,7 +48,6 @@ if isWindows; then
 
         curl -o mingw.7z "${MIRRORS_BASE}/${mingw_archive}"
         7z x -y mingw.7z > /dev/null
-        curl -o "${mingw_dir}/bin/gdborig.exe" "${MIRRORS_BASE}/2017-04-20-${bits}bit-gdborig.exe"
         ciCommandAddPath "$(pwd)/${mingw_dir}/bin"
     fi
 fi
diff --git a/src/ci/scripts/should-skip-this.sh b/src/ci/scripts/should-skip-this.sh
index 85d772253..48127166a 100755
--- a/src/ci/scripts/should-skip-this.sh
+++ b/src/ci/scripts/should-skip-this.sh
@@ -1,46 +1,11 @@
 #!/bin/bash
-# Set the SKIP_JOB environment variable if this job is supposed to only run
-# when submodules are updated and they were not. The following time consuming
-# tasks will be skipped when the environment variable is present.
+# Set the SKIP_JOB environment variable if this job is not supposed to run on the current builder.
 
 set -euo pipefail
 IFS=$'\n\t'
 
 source "$(cd "$(dirname "$0")" && pwd)/../shared.sh"
 
-if [[ -n "${CI_ONLY_WHEN_SUBMODULES_CHANGED-}" ]]; then
-    git fetch "https://github.com/$GITHUB_REPOSITORY" "$GITHUB_BASE_REF"
-    BASE_COMMIT="$(git merge-base FETCH_HEAD HEAD)"
-
-    echo "Searching for toolstate changes between $BASE_COMMIT and $(git rev-parse HEAD)"
-
-    if git diff "$BASE_COMMIT" | grep --quiet "^index .* 160000"; then
-        # Submodules pseudo-files inside git have the 160000 permissions, so when
-        # those files are present in the diff a submodule was updated.
-        echo "Submodules were updated"
-    elif ! (git diff --quiet "$BASE_COMMIT" -- \
-             src/tools/clippy src/tools/rustfmt src/tools/miri \
-             library/std/src/sys); then
-        # There is not an easy blanket search for subtrees. For now, manually list
-        # the subtrees.
-        # Also run this when the platform-specific parts of std change, in case
-        # that breaks Miri.
-        echo "Tool subtrees were updated"
-    elif ! (git diff --quiet "$BASE_COMMIT" -- \
-             tests/rustdoc-gui \
-             src/librustdoc \
-             src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile \
-             src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version \
-             src/tools/rustdoc-gui); then
-        # There was a change in either rustdoc or in its GUI tests.
-        echo "Rustdoc was updated"
-    else
-        echo "Not executing this job since no submodules nor subtrees were updated"
-        ciCommandSetEnv SKIP_JOB 1
-        exit 0
-    fi
-fi
-
 if [[ -n "${CI_ONLY_WHEN_CHANNEL-}" ]]; then
     if [[ "${CI_ONLY_WHEN_CHANNEL}" = "$(cat src/ci/channel)" ]]; then
         echo "The channel is the expected one"
diff --git a/src/ci/stage-build.py b/src/ci/stage-build.py
new file mode 100644
index 000000000..bd8fd524a
--- /dev/null
+++ b/src/ci/stage-build.py
@@ -0,0 +1,842 @@
+#!/usr/bin/env python3
+# ignore-tidy-linelength
+
+# Compatible with Python 3.6+
+
+import contextlib
+import getpass
+import glob
+import json
+import logging
+import os
+import pprint
+import shutil
+import subprocess
+import sys
+import time
+import traceback
+import urllib.request
+from io import StringIO
+from pathlib import Path
+from typing import Callable, ContextManager, Dict, Iterable, Iterator, List, Optional, \
+    Tuple, Union
+
+PGO_HOST = os.environ["PGO_HOST"]
+
+LOGGER = logging.getLogger("stage-build")
+
+LLVM_PGO_CRATES = [
+    "syn-1.0.89",
+    "cargo-0.60.0",
+    "serde-1.0.136",
+    "ripgrep-13.0.0",
+    "regex-1.5.5",
+    "clap-3.1.6",
+    "hyper-0.14.18"
+]
+
+RUSTC_PGO_CRATES = [
+    "externs",
+    "ctfe-stress-5",
+    "cargo-0.60.0",
+    "token-stream-stress",
+    "match-stress",
+    "tuple-stress",
+    "diesel-1.4.8",
+    "bitmaps-3.1.0"
+]
+
+LLVM_BOLT_CRATES = LLVM_PGO_CRATES
+
+
+class Pipeline:
+    # Paths
+    def checkout_path(self) -> Path:
+        """
+        The root checkout, where the source is located.
+        """
+        raise NotImplementedError
+
+    def downloaded_llvm_dir(self) -> Path:
+        """
+        Directory where the host LLVM is located.
+        """
+        raise NotImplementedError
+
+    def build_root(self) -> Path:
+        """
+        The main directory where the build occurs.
+        """
+        raise NotImplementedError
+
+    def build_artifacts(self) -> Path:
+        return self.build_root() / "build" / PGO_HOST
+
+    def rustc_stage_0(self) -> Path:
+        return self.build_artifacts() / "stage0" / "bin" / "rustc"
+
+    def cargo_stage_0(self) -> Path:
+        return self.build_artifacts() / "stage0" / "bin" / "cargo"
+
+    def rustc_stage_2(self) -> Path:
+        return self.build_artifacts() / "stage2" / "bin" / "rustc"
+
+    def opt_artifacts(self) -> Path:
+        raise NotImplementedError
+
+    def llvm_profile_dir_root(self) -> Path:
+        return self.opt_artifacts() / "llvm-pgo"
+
+    def llvm_profile_merged_file(self) -> Path:
+        return self.opt_artifacts() / "llvm-pgo.profdata"
+
+    def rustc_perf_dir(self) -> Path:
+        return self.opt_artifacts() / "rustc-perf"
+
+    def build_rustc_perf(self):
+        raise NotImplementedError()
+
+    def rustc_profile_dir_root(self) -> Path:
+        return self.opt_artifacts() / "rustc-pgo"
+
+    def rustc_profile_merged_file(self) -> Path:
+        return self.opt_artifacts() / "rustc-pgo.profdata"
+
+    def rustc_profile_template_path(self) -> Path:
+        """
+        The profile data is written into a single filepath that is being repeatedly merged when each
+        rustc invocation ends. Empirically, this can result in some profiling data being lost. That's
+        why we override the profile path to include the PID. This will produce many more profiling
+        files, but the resulting profile will produce a slightly faster rustc binary.
+        """
+        return self.rustc_profile_dir_root() / "default_%m_%p.profraw"
+
+    def supports_bolt(self) -> bool:
+        raise NotImplementedError
+
+    def llvm_bolt_profile_merged_file(self) -> Path:
+        return self.opt_artifacts() / "bolt.profdata"
+
+    def metrics_path(self) -> Path:
+        return self.build_root() / "build" / "metrics.json"
+
+
+class LinuxPipeline(Pipeline):
+    def checkout_path(self) -> Path:
+        return Path("/checkout")
+
+    def downloaded_llvm_dir(self) -> Path:
+        return Path("/rustroot")
+
+    def build_root(self) -> Path:
+        return self.checkout_path() / "obj"
+
+    def opt_artifacts(self) -> Path:
+        return Path("/tmp/tmp-multistage/opt-artifacts")
+
+    def build_rustc_perf(self):
+        # /tmp/rustc-perf comes from the Dockerfile
+        shutil.copytree("/tmp/rustc-perf", self.rustc_perf_dir())
+        cmd(["chown", "-R", f"{getpass.getuser()}:", self.rustc_perf_dir()])
+
+        with change_cwd(self.rustc_perf_dir()):
+            cmd([self.cargo_stage_0(), "build", "-p", "collector"], env=dict(
+                RUSTC=str(self.rustc_stage_0()),
+                RUSTC_BOOTSTRAP="1"
+            ))
+
+    def supports_bolt(self) -> bool:
+        return True
+
+
+class WindowsPipeline(Pipeline):
+    def __init__(self):
+        self.checkout_dir = Path(os.getcwd())
+
+    def checkout_path(self) -> Path:
+        return self.checkout_dir
+
+    def downloaded_llvm_dir(self) -> Path:
+        return self.checkout_path() / "citools" / "clang-rust"
+
+    def build_root(self) -> Path:
+        return self.checkout_path()
+
+    def opt_artifacts(self) -> Path:
+        return self.checkout_path() / "opt-artifacts"
+
+    def rustc_stage_0(self) -> Path:
+        return super().rustc_stage_0().with_suffix(".exe")
+
+    def cargo_stage_0(self) -> Path:
+        return super().cargo_stage_0().with_suffix(".exe")
+
+    def rustc_stage_2(self) -> Path:
+        return super().rustc_stage_2().with_suffix(".exe")
+
+    def build_rustc_perf(self):
+        # rustc-perf version from 2022-07-22
+        perf_commit = "3c253134664fdcba862c539d37f0de18557a9a4c"
+        rustc_perf_zip_path = self.opt_artifacts() / "perf.zip"
+
+        def download_rustc_perf():
+            download_file(
+                f"https://github.com/rust-lang/rustc-perf/archive/{perf_commit}.zip",
+                rustc_perf_zip_path
+            )
+            with change_cwd(self.opt_artifacts()):
+                unpack_archive(rustc_perf_zip_path)
+                move_path(Path(f"rustc-perf-{perf_commit}"), self.rustc_perf_dir())
+                delete_file(rustc_perf_zip_path)
+
+        retry_action(download_rustc_perf, "Download rustc-perf")
+
+        with change_cwd(self.rustc_perf_dir()):
+            cmd([self.cargo_stage_0(), "build", "-p", "collector"], env=dict(
+                RUSTC=str(self.rustc_stage_0()),
+                RUSTC_BOOTSTRAP="1"
+            ))
+
+    def rustc_profile_template_path(self) -> Path:
+        """
+        On Windows, we don't have enough space to use separate files for each rustc invocation.
+        Therefore, we use a single file for the generated profiles.
+        """
+        return self.rustc_profile_dir_root() / "default_%m.profraw"
+
+    def supports_bolt(self) -> bool:
+        return False
+
+
+def get_timestamp() -> float:
+    return time.time()
+
+
+Duration = float
+
+
+def iterate_timers(timer: "Timer", name: str, level: int = 0) -> Iterator[
+    Tuple[int, str, Duration]]:
+    """
+    Hierarchically iterate the children of a timer, in a depth-first order.
+    """
+    yield (level, name, timer.total_duration())
+    for (child_name, child_timer) in timer.children:
+        yield from iterate_timers(child_timer, child_name, level=level + 1)
+
+
+class Timer:
+    def __init__(self, parent_names: Tuple[str, ...] = ()):
+        self.children: List[Tuple[str, Timer]] = []
+        self.section_active = False
+        self.parent_names = parent_names
+        self.duration_excluding_children: Duration = 0
+
+    @contextlib.contextmanager
+    def section(self, name: str) -> ContextManager["Timer"]:
+        assert not self.section_active
+        self.section_active = True
+
+        start = get_timestamp()
+        exc = None
+
+        child_timer = Timer(parent_names=self.parent_names + (name,))
+        full_name = " > ".join(child_timer.parent_names)
+        try:
+            LOGGER.info(f"Section `{full_name}` starts")
+            yield child_timer
+        except BaseException as exception:
+            exc = exception
+            raise
+        finally:
+            end = get_timestamp()
+            duration = end - start
+
+            child_timer.duration_excluding_children = duration - child_timer.total_duration()
+            self.add_child(name, child_timer)
+            if exc is None:
+                LOGGER.info(f"Section `{full_name}` ended: OK ({duration:.2f}s)")
+            else:
+                LOGGER.info(f"Section `{full_name}` ended: FAIL ({duration:.2f}s)")
+            self.section_active = False
+
+    def total_duration(self) -> Duration:
+        return self.duration_excluding_children + sum(
+            c.total_duration() for (_, c) in self.children)
+
+    def has_children(self) -> bool:
+        return len(self.children) > 0
+
+    def print_stats(self):
+        rows = []
+        for (child_name, child_timer) in self.children:
+            for (level, name, duration) in iterate_timers(child_timer, child_name, level=0):
+                label = f"{'  ' * level}{name}:"
+                rows.append((label, duration))
+
+        # Empty row
+        rows.append(("", ""))
+
+        total_duration_label = "Total duration:"
+        total_duration = self.total_duration()
+        rows.append((total_duration_label, humantime(total_duration)))
+
+        space_after_label = 2
+        max_label_length = max(16, max(len(label) for (label, _) in rows)) + space_after_label
+
+        table_width = max_label_length + 23
+        divider = "-" * table_width
+
+        with StringIO() as output:
+            print(divider, file=output)
+            for (label, duration) in rows:
+                if isinstance(duration, Duration):
+                    pct = (duration / total_duration) * 100
+                    value = f"{duration:>12.2f}s ({pct:>5.2f}%)"
+                else:
+                    value = f"{duration:>{len(total_duration_label) + 7}}"
+                print(f"{label:<{max_label_length}} {value}", file=output)
+            print(divider, file=output, end="")
+            LOGGER.info(f"Timer results\n{output.getvalue()}")
+
+    def add_child(self, name: str, timer: "Timer"):
+        self.children.append((name, timer))
+
+    def add_duration(self, name: str, duration: Duration):
+        timer = Timer(parent_names=self.parent_names + (name,))
+        timer.duration_excluding_children = duration
+        self.add_child(name, timer)
+
+
+class BuildStep:
+    def __init__(self, type: str, children: List["BuildStep"], duration: float):
+        self.type = type
+        self.children = children
+        self.duration = duration
+
+    def find_all_by_type(self, type: str) -> Iterator["BuildStep"]:
+        if type == self.type:
+            yield self
+        for child in self.children:
+            yield from child.find_all_by_type(type)
+
+    def __repr__(self):
+        return f"BuildStep(type={self.type}, duration={self.duration}, children={len(self.children)})"
+
+
+def load_last_metrics(path: Path) -> BuildStep:
+    """
+    Loads the metrics of the most recent bootstrap execution from a metrics.json file.
+    """
+    with open(path, "r") as f:
+        metrics = json.load(f)
+    invocation = metrics["invocations"][-1]
+
+    def parse(entry) -> Optional[BuildStep]:
+        if "kind" not in entry or entry["kind"] != "rustbuild_step":
+            return None
+        type = entry.get("type", "")
+        duration = entry.get("duration_excluding_children_sec", 0)
+        children = []
+
+        for child in entry.get("children", ()):
+            step = parse(child)
+            if step is not None:
+                children.append(step)
+                duration += step.duration
+        return BuildStep(type=type, children=children, duration=duration)
+
+    children = [parse(child) for child in invocation.get("children", ())]
+    return BuildStep(
+        type="root",
+        children=children,
+        duration=invocation.get("duration_including_children_sec", 0)
+    )
+
+
+@contextlib.contextmanager
+def change_cwd(dir: Path):
+    """
+    Temporarily change working directory to `dir`.
+    """
+    cwd = os.getcwd()
+    LOGGER.debug(f"Changing working dir from `{cwd}` to `{dir}`")
+    os.chdir(dir)
+    try:
+        yield
+    finally:
+        LOGGER.debug(f"Reverting working dir to `{cwd}`")
+        os.chdir(cwd)
+
+
+def humantime(time_s: float) -> str:
+    hours = time_s // 3600
+    time_s = time_s % 3600
+    minutes = time_s // 60
+    seconds = time_s % 60
+
+    result = ""
+    if hours > 0:
+        result += f"{int(hours)}h "
+    if minutes > 0:
+        result += f"{int(minutes)}m "
+    result += f"{round(seconds)}s"
+    return result
+
+
+def move_path(src: Path, dst: Path):
+    LOGGER.info(f"Moving `{src}` to `{dst}`")
+    shutil.move(src, dst)
+
+
+def delete_file(path: Path):
+    LOGGER.info(f"Deleting file `{path}`")
+    os.unlink(path)
+
+
+def delete_directory(path: Path):
+    LOGGER.info(f"Deleting directory `{path}`")
+    shutil.rmtree(path)
+
+
+def unpack_archive(archive: Path):
+    LOGGER.info(f"Unpacking archive `{archive}`")
+    shutil.unpack_archive(archive)
+
+
+def download_file(src: str, target: Path):
+    LOGGER.info(f"Downloading `{src}` into `{target}`")
+    urllib.request.urlretrieve(src, str(target))
+
+
+def retry_action(action, name: str, max_fails: int = 5):
+    LOGGER.info(f"Attempting to perform action `{name}` with retry")
+    for iteration in range(max_fails):
+        LOGGER.info(f"Attempt {iteration + 1}/{max_fails}")
+        try:
+            action()
+            return
+        except:
+            LOGGER.error(f"Action `{name}` has failed\n{traceback.format_exc()}")
+
+    raise Exception(f"Action `{name}` has failed after {max_fails} attempts")
+
+
+def cmd(
+        args: List[Union[str, Path]],
+        env: Optional[Dict[str, str]] = None,
+        output_path: Optional[Path] = None
+):
+    args = [str(arg) for arg in args]
+
+    environment = os.environ.copy()
+
+    cmd_str = ""
+    if env is not None:
+        environment.update(env)
+        cmd_str += " ".join(f"{k}={v}" for (k, v) in (env or {}).items())
+        cmd_str += " "
+    cmd_str += " ".join(args)
+    if output_path is not None:
+        cmd_str += f" > {output_path}"
+    LOGGER.info(f"Executing `{cmd_str}`")
+
+    if output_path is not None:
+        with open(output_path, "w") as f:
+            return subprocess.run(
+                args,
+                env=environment,
+                check=True,
+                stdout=f
+            )
+    return subprocess.run(args, env=environment, check=True)
+
+
+def run_compiler_benchmarks(
+        pipeline: Pipeline,
+        profiles: List[str],
+        scenarios: List[str],
+        crates: List[str],
+        env: Optional[Dict[str, str]] = None
+):
+    env = env if env is not None else {}
+
+    # Compile libcore, both in opt-level=0 and opt-level=3
+    with change_cwd(pipeline.build_root()):
+        cmd([
+            pipeline.rustc_stage_2(),
+            "--edition", "2021",
+            "--crate-type", "lib",
+            str(pipeline.checkout_path() / "library/core/src/lib.rs"),
+            "--out-dir", pipeline.opt_artifacts()
+        ], env=dict(RUSTC_BOOTSTRAP="1", **env))
+
+        cmd([
+            pipeline.rustc_stage_2(),
+            "--edition", "2021",
+            "--crate-type", "lib",
+            "-Copt-level=3",
+            str(pipeline.checkout_path() / "library/core/src/lib.rs"),
+            "--out-dir", pipeline.opt_artifacts()
+        ], env=dict(RUSTC_BOOTSTRAP="1", **env))
+
+    # Run rustc-perf benchmarks
+    # Benchmark using profile_local with eprintln, which essentially just means
+    # don't actually benchmark -- just make sure we run rustc a bunch of times.
+    with change_cwd(pipeline.rustc_perf_dir()):
+        cmd([
+            pipeline.cargo_stage_0(),
+            "run",
+            "-p", "collector", "--bin", "collector", "--",
+            "profile_local", "eprintln",
+            pipeline.rustc_stage_2(),
+            "--id", "Test",
+            "--cargo", pipeline.cargo_stage_0(),
+            "--profiles", ",".join(profiles),
+            "--scenarios", ",".join(scenarios),
+            "--include", ",".join(crates)
+        ], env=dict(
+            RUST_LOG="collector=debug",
+            RUSTC=str(pipeline.rustc_stage_0()),
+            RUSTC_BOOTSTRAP="1",
+            **env
+        ))
+
+
+# https://stackoverflow.com/a/31631711/1107768
+def format_bytes(size: int) -> str:
+    """Return the given bytes as a human friendly KiB, MiB or GiB string."""
+    KB = 1024
+    MB = KB ** 2  # 1,048,576
+    GB = KB ** 3  # 1,073,741,824
+    TB = KB ** 4  # 1,099,511,627,776
+
+    if size < KB:
+        return f"{size} B"
+    elif KB <= size < MB:
+        return f"{size / KB:.2f} KiB"
+    elif MB <= size < GB:
+        return f"{size / MB:.2f} MiB"
+    elif GB <= size < TB:
+        return f"{size / GB:.2f} GiB"
+    else:
+        return str(size)
+
+
+# https://stackoverflow.com/a/63307131/1107768
+def count_files(path: Path) -> int:
+    return sum(1 for p in path.rglob("*") if p.is_file())
+
+
+def count_files_with_prefix(path: Path) -> int:
+    return sum(1 for p in glob.glob(f"{path}*") if Path(p).is_file())
+
+
+# https://stackoverflow.com/a/55659577/1107768
+def get_path_size(path: Path) -> int:
+    if path.is_dir():
+        return sum(p.stat().st_size for p in path.rglob("*"))
+    return path.stat().st_size
+
+
+def get_path_prefix_size(path: Path) -> int:
+    """
+    Get size of all files beginning with the prefix `path`.
+    Alternative to shell `du -sh <path>*`.
+    """
+    return sum(Path(p).stat().st_size for p in glob.glob(f"{path}*"))
+
+
+def get_files(directory: Path, filter: Optional[Callable[[Path], bool]] = None) -> Iterable[Path]:
+    for file in os.listdir(directory):
+        path = directory / file
+        if filter is None or filter(path):
+            yield path
+
+
+def build_rustc(
+        pipeline: Pipeline,
+        args: List[str],
+        env: Optional[Dict[str, str]] = None
+):
+    arguments = [
+                    sys.executable,
+                    pipeline.checkout_path() / "x.py",
+                    "build",
+                    "--target", PGO_HOST,
+                    "--host", PGO_HOST,
+                    "--stage", "2",
+                    "library/std"
+                ] + args
+    cmd(arguments, env=env)
+
+
+def create_pipeline() -> Pipeline:
+    if sys.platform == "linux":
+        return LinuxPipeline()
+    elif sys.platform in ("cygwin", "win32"):
+        return WindowsPipeline()
+    else:
+        raise Exception(f"Optimized build is not supported for platform {sys.platform}")
+
+
+def gather_llvm_profiles(pipeline: Pipeline):
+    LOGGER.info("Running benchmarks with PGO instrumented LLVM")
+    run_compiler_benchmarks(
+        pipeline,
+        profiles=["Debug", "Opt"],
+        scenarios=["Full"],
+        crates=LLVM_PGO_CRATES
+    )
+
+    profile_path = pipeline.llvm_profile_merged_file()
+    LOGGER.info(f"Merging LLVM PGO profiles to {profile_path}")
+    cmd([
+        pipeline.downloaded_llvm_dir() / "bin" / "llvm-profdata",
+        "merge",
+        "-o", profile_path,
+        pipeline.llvm_profile_dir_root()
+    ])
+
+    LOGGER.info("LLVM PGO statistics")
+    LOGGER.info(f"{profile_path}: {format_bytes(get_path_size(profile_path))}")
+    LOGGER.info(
+        f"{pipeline.llvm_profile_dir_root()}: {format_bytes(get_path_size(pipeline.llvm_profile_dir_root()))}")
+    LOGGER.info(f"Profile file count: {count_files(pipeline.llvm_profile_dir_root())}")
+
+    # We don't need the individual .profraw files now that they have been merged
+    # into a final .profdata
+    delete_directory(pipeline.llvm_profile_dir_root())
+
+
+def gather_rustc_profiles(pipeline: Pipeline):
+    LOGGER.info("Running benchmarks with PGO instrumented rustc")
+
+    # Here we're profiling the `rustc` frontend, so we also include `Check`.
+    # The benchmark set includes various stress tests that put the frontend under pressure.
+    run_compiler_benchmarks(
+        pipeline,
+        profiles=["Check", "Debug", "Opt"],
+        scenarios=["All"],
+        crates=RUSTC_PGO_CRATES,
+        env=dict(
+            LLVM_PROFILE_FILE=str(pipeline.rustc_profile_template_path())
+        )
+    )
+
+    profile_path = pipeline.rustc_profile_merged_file()
+    LOGGER.info(f"Merging Rustc PGO profiles to {profile_path}")
+    cmd([
+        pipeline.build_artifacts() / "llvm" / "bin" / "llvm-profdata",
+        "merge",
+        "-o", profile_path,
+        pipeline.rustc_profile_dir_root()
+    ])
+
+    LOGGER.info("Rustc PGO statistics")
+    LOGGER.info(f"{profile_path}: {format_bytes(get_path_size(profile_path))}")
+    LOGGER.info(
+        f"{pipeline.rustc_profile_dir_root()}: {format_bytes(get_path_size(pipeline.rustc_profile_dir_root()))}")
+    LOGGER.info(f"Profile file count: {count_files(pipeline.rustc_profile_dir_root())}")
+
+    # We don't need the individual .profraw files now that they have been merged
+    # into a final .profdata
+    delete_directory(pipeline.rustc_profile_dir_root())
+
+
+def gather_llvm_bolt_profiles(pipeline: Pipeline):
+    LOGGER.info("Running benchmarks with BOLT instrumented LLVM")
+    run_compiler_benchmarks(
+        pipeline,
+        profiles=["Check", "Debug", "Opt"],
+        scenarios=["Full"],
+        crates=LLVM_BOLT_CRATES
+    )
+
+    merged_profile_path = pipeline.llvm_bolt_profile_merged_file()
+    profile_files_path = Path("/tmp/prof.fdata")
+    LOGGER.info(f"Merging LLVM BOLT profiles to {merged_profile_path}")
+
+    profile_files = sorted(glob.glob(f"{profile_files_path}*"))
+    cmd([
+        "merge-fdata",
+        *profile_files,
+    ], output_path=merged_profile_path)
+
+    LOGGER.info("LLVM BOLT statistics")
+    LOGGER.info(f"{merged_profile_path}: {format_bytes(get_path_size(merged_profile_path))}")
+    LOGGER.info(
+        f"{profile_files_path}: {format_bytes(get_path_prefix_size(profile_files_path))}")
+    LOGGER.info(f"Profile file count: {count_files_with_prefix(profile_files_path)}")
+
+
+def clear_llvm_files(pipeline: Pipeline):
+    """
+    Rustbuild currently doesn't support rebuilding LLVM when PGO options
+    change (or any other llvm-related options); so just clear out the relevant
+    directories ourselves.
+    """
+    LOGGER.info("Clearing LLVM build files")
+    delete_directory(pipeline.build_artifacts() / "llvm")
+    delete_directory(pipeline.build_artifacts() / "lld")
+
+
+def print_binary_sizes(pipeline: Pipeline):
+    bin_dir = pipeline.build_artifacts() / "stage2" / "bin"
+    binaries = get_files(bin_dir)
+
+    lib_dir = pipeline.build_artifacts() / "stage2" / "lib"
+    libraries = get_files(lib_dir, lambda p: p.suffix == ".so")
+
+    paths = sorted(binaries) + sorted(libraries)
+    with StringIO() as output:
+        for path in paths:
+            path_str = f"{path.name}:"
+            print(f"{path_str:<50}{format_bytes(path.stat().st_size):>14}", file=output)
+        LOGGER.info(f"Rustc binary size\n{output.getvalue()}")
+
+
+def print_free_disk_space(pipeline: Pipeline):
+    usage = shutil.disk_usage(pipeline.opt_artifacts())
+    total = usage.total
+    used = usage.used
+    free = usage.free
+
+    logging.info(
+        f"Free disk space: {format_bytes(free)} out of total {format_bytes(total)} ({(used / total) * 100:.2f}% used)")
+
+
+def log_metrics(step: BuildStep):
+    substeps: List[Tuple[int, BuildStep]] = []
+
+    def visit(step: BuildStep, level: int):
+        substeps.append((level, step))
+        for child in step.children:
+            visit(child, level=level + 1)
+
+    visit(step, 0)
+
+    output = StringIO()
+    for (level, step) in substeps:
+        label = f"{'.' * level}{step.type}"
+        print(f"{label:<65}{step.duration:>8.2f}s", file=output)
+    logging.info(f"Build step durations\n{output.getvalue()}")
+
+
+def record_metrics(pipeline: Pipeline, timer: Timer):
+    metrics = load_last_metrics(pipeline.metrics_path())
+    if metrics is None:
+        return
+    llvm_steps = tuple(metrics.find_all_by_type("bootstrap::native::Llvm"))
+    assert len(llvm_steps) > 0
+    llvm_duration = sum(step.duration for step in llvm_steps)
+
+    rustc_steps = tuple(metrics.find_all_by_type("bootstrap::compile::Rustc"))
+    assert len(rustc_steps) > 0
+    rustc_duration = sum(step.duration for step in rustc_steps)
+
+    # The LLVM step is part of the Rustc step
+    rustc_duration -= llvm_duration
+
+    timer.add_duration("LLVM", llvm_duration)
+    timer.add_duration("Rustc", rustc_duration)
+
+    log_metrics(metrics)
+
+
+def execute_build_pipeline(timer: Timer, pipeline: Pipeline, final_build_args: List[str]):
+    # Clear and prepare tmp directory
+    shutil.rmtree(pipeline.opt_artifacts(), ignore_errors=True)
+    os.makedirs(pipeline.opt_artifacts(), exist_ok=True)
+
+    pipeline.build_rustc_perf()
+
+    # Stage 1: Build rustc + PGO instrumented LLVM
+    with timer.section("Stage 1 (LLVM PGO)") as stage1:
+        with stage1.section("Build rustc and LLVM") as rustc_build:
+            build_rustc(pipeline, args=[
+                "--llvm-profile-generate"
+            ], env=dict(
+                LLVM_PROFILE_DIR=str(pipeline.llvm_profile_dir_root() / "prof-%p")
+            ))
+            record_metrics(pipeline, rustc_build)
+
+        with stage1.section("Gather profiles"):
+            gather_llvm_profiles(pipeline)
+        print_free_disk_space(pipeline)
+
+    clear_llvm_files(pipeline)
+    final_build_args += [
+        "--llvm-profile-use",
+        pipeline.llvm_profile_merged_file()
+    ]
+
+    # Stage 2: Build PGO instrumented rustc + LLVM
+    with timer.section("Stage 2 (rustc PGO)") as stage2:
+        with stage2.section("Build rustc and LLVM") as rustc_build:
+            build_rustc(pipeline, args=[
+                "--rust-profile-generate",
+                pipeline.rustc_profile_dir_root()
+            ])
+            record_metrics(pipeline, rustc_build)
+
+        with stage2.section("Gather profiles"):
+            gather_rustc_profiles(pipeline)
+        print_free_disk_space(pipeline)
+
+    clear_llvm_files(pipeline)
+    final_build_args += [
+        "--rust-profile-use",
+        pipeline.rustc_profile_merged_file()
+    ]
+
+    # Stage 3: Build rustc + BOLT instrumented LLVM
+    if pipeline.supports_bolt():
+        with timer.section("Stage 3 (LLVM BOLT)") as stage3:
+            with stage3.section("Build rustc and LLVM") as rustc_build:
+                build_rustc(pipeline, args=[
+                    "--llvm-profile-use",
+                    pipeline.llvm_profile_merged_file(),
+                    "--llvm-bolt-profile-generate",
+                ])
+                record_metrics(pipeline, rustc_build)
+
+            with stage3.section("Gather profiles"):
+                gather_llvm_bolt_profiles(pipeline)
+
+        print_free_disk_space(pipeline)
+        clear_llvm_files(pipeline)
+        final_build_args += [
+            "--llvm-bolt-profile-use",
+            pipeline.llvm_bolt_profile_merged_file()
+        ]
+
+    # Stage 4: Build PGO optimized rustc + PGO/BOLT optimized LLVM
+    with timer.section("Stage 4 (final build)") as stage4:
+        cmd(final_build_args)
+        record_metrics(pipeline, stage4)
+
+
+if __name__ == "__main__":
+    logging.basicConfig(
+        level=logging.DEBUG,
+        format="%(name)s %(levelname)-4s: %(message)s",
+    )
+
+    LOGGER.info(f"Running multi-stage build using Python {sys.version}")
+    LOGGER.info(f"Environment values\n{pprint.pformat(dict(os.environ), indent=2)}")
+
+    build_args = sys.argv[1:]
+
+    timer = Timer()
+    pipeline = create_pipeline()
+    try:
+        execute_build_pipeline(timer, pipeline, build_args)
+    except BaseException as e:
+        LOGGER.error("The multi-stage build has failed")
+        raise e
+    finally:
+        timer.print_stats()
+        print_free_disk_space(pipeline)
+
+    print_binary_sizes(pipeline)