Auto merge of rust-lang#122709 - onur-ozkan:use-precompiled-rustc-by-default, r=<try>

prefer precompiled rustc for x86_64-gnu

*-to be filled-*

blocker for rust-lang#119899
r? ghost

Author: bors

.github/workflows/ci.yml

@@ -58,9 +58,10 @@ jobs:
           - name: mingw-check-tidy
             os: ubuntu-20.04-4core-16gb
             env: {}
-          - name: x86_64-gnu-llvm-17
+          - name: x86_64-gnu
             env:
               ENABLE_GCC_CODEGEN: "1"
+              DOWNLOAD_RUSTC: "1"
             os: ubuntu-20.04-16core-64gb
           - name: x86_64-gnu-tools
             os: ubuntu-20.04-16core-64gb
@@ -294,8 +295,9 @@ jobs:
             os: ubuntu-20.04-8core-32gb
             env: {}
           - name: x86_64-gnu
+            env:
+              DOWNLOAD_RUSTC: "1"
             os: ubuntu-20.04-4core-16gb
-            env: {}
           - name: x86_64-gnu-stable
             env:
               IMAGE: x86_64-gnu
@@ -593,6 +595,7 @@ jobs:
     name: "try - ${{ matrix.name }}"
     env:
       DIST_TRY_BUILD: 1
+      DOWNLOAD_RUSTC: 1
       CI_JOB_NAME: "${{ matrix.name }}"
       CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse
       HEAD_SHA: "${{ github.event.pull_request.head.sha || github.sha }}"

src/bootstrap/src/core/build_steps/test.rs

@@ -3223,6 +3223,11 @@ impl Step for CodegenCranelift {
             return;
         }
 
+        if builder.download_rustc() {
+            builder.info("pre-compiled/downloaded rustc detected. skipping");
+            return;
+        }
+
         if !target_supports_cranelift_backend(run.target) {
             builder.info("target not supported by rustc_codegen_cranelift. skipping");
             return;
@@ -3344,6 +3349,11 @@ impl Step for CodegenGCC {
             return;
         }
 
+        if builder.download_rustc() {
+            builder.info("pre-compiled/downloaded rustc detected. skipping");
+            return;
+        }
+
         let triple = run.target.triple;
         let target_supported =
             if triple.contains("linux") { triple.contains("x86_64") } else { false };

src/bootstrap/src/core/config/config.rs

@@ -21,6 +21,7 @@ use crate::core::config::flags::{Color, Flags, Warnings};
 use crate::utils::cache::{Interned, INTERNER};
 use crate::utils::channel::{self, GitInfo};
 use crate::utils::helpers::{exe, output, t};
+use build_helper::ci::CiEnv;
 use build_helper::exit;
 use build_helper::util::fail;
 use semver::Version;
@@ -2418,13 +2419,16 @@ impl Config {
         let compiler = format!("{top_level}/compiler/");
         let library = format!("{top_level}/library/");
 
+        // If we are running in CI, the current commit will never have artifacts already built.
+        let tip_commit = if CiEnv::is_ci() { "HEAD^" } else { "HEAD" };
+
         // Look for a version to compare to based on the current commit.
         // Only commits merged by bors will have CI artifacts.
         let merge_base = output(
             self.git()
                 .arg("rev-list")
                 .arg(format!("--author={}", self.stage0_metadata.config.git_merge_commit_email))
-                .args(["-n1", "--first-parent", "HEAD"]),
+                .args(["-n1", "--first-parent", tip_commit]),
         );
         let commit = merge_base.trim_end();
         if commit.is_empty() {

src/ci/docker/host-x86_64/x86_64-gnu/Dockerfile

@@ -17,14 +17,29 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   pkg-config \
   xz-utils \
   mingw-w64 \
+  # libgccjit dependencies
+  flex \
+  libmpfr-dev \
+  libgmp-dev \
+  libmpc3 \
+  libmpc-dev \
   && rm -rf /var/lib/apt/lists/*
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+# Fix rustc_codegen_gcc lto issues.
+ENV GCC_EXEC_PREFIX="/usr/lib/gcc/"
+
 ENV RUST_CONFIGURE_ARGS \
  --build=x86_64-unknown-linux-gnu \
  --enable-sanitizers \
  --enable-profiler \
  --enable-compiler-docs
+
+COPY host-x86_64/dist-x86_64-linux/shared.sh /scripts/
+COPY host-x86_64/dist-x86_64-linux/build-gccjit.sh /scripts/
+
+RUN /scripts/build-gccjit.sh /scripts
+
 ENV SCRIPT python3 ../x.py --stage 2 test

src/ci/docker/run.sh

@@ -310,6 +310,11 @@ if [ "$ENABLE_GCC_CODEGEN" = "1" ]; then
   echo "Setting extra environment values for docker: $extra_env"
 fi
 
+if [ "$DOWNLOAD_RUSTC" = "1" ]; then
+  extra_env="$extra_env --env DOWNLOAD_RUSTC=1"
+  echo "Setting extra environment values for docker: $extra_env"
+fi
+
 docker \
   run \
   --workdir /checkout/obj \

src/ci/github-actions/ci.yml

@@ -357,9 +357,10 @@ jobs:
           - name: mingw-check-tidy
             <<: *job-linux-4c
 
-          - name: x86_64-gnu-llvm-17
+          - name: x86_64-gnu
             env:
               ENABLE_GCC_CODEGEN: "1"
+              DOWNLOAD_RUSTC: "1"
             <<: *job-linux-16c
 
           - name: x86_64-gnu-tools
@@ -476,6 +477,8 @@ jobs:
             <<: *job-linux-8c
 
           - name: x86_64-gnu
+            env:
+              DOWNLOAD_RUSTC: "1"
             <<: *job-linux-4c
 
           # This job ensures commits landing on nightly still pass the full
@@ -754,6 +757,7 @@ jobs:
     name: try - ${{ matrix.name }}
     env:
       DIST_TRY_BUILD: 1
+      DOWNLOAD_RUSTC: 1
       <<: [*shared-ci-variables, *prod-variables]
     if: github.event_name == 'push' && (((github.ref == 'refs/heads/try' || github.ref == 'refs/heads/try-perf') && github.repository == 'rust-lang-ci/rust') || ((github.ref == 'refs/heads/automation/bors/try') && github.repository == 'rust-lang/rust'))
     strategy:

src/ci/run.sh

@@ -105,6 +105,11 @@ export RUST_RELEASE_CHANNEL=$(releaseChannel)
 RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --release-channel=$RUST_RELEASE_CHANNEL"
 
 if [ "$DEPLOY$DEPLOY_ALT" = "1" ]; then
+  if [ "$DOWNLOAD_RUSTC" = 1 ]; then
+    echo "ERROR: "DOWNLOAD_RUSTC" should not be set in dist builders!" >&2
+    exit 1
+  fi
+
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-llvm-static-stdcpp"
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set rust.remap-debuginfo"
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --debuginfo-level-std=1"
@@ -139,6 +144,10 @@ else
     RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-llvm-assertions"
   fi
 
+  if [ "$DOWNLOAD_RUSTC" = 1 ]; then
+    RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set rust.download-rustc=if-unchanged"
+  fi
+
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set rust.verify-llvm-ir"
 
   # When running gcc backend tests, we need to install `libgccjit` and to not run llvm codegen