Auto merge of #99464 - nikic:llvm-15, r=cuviper

Update to LLVM 15

For preliminary testing. Some LLVM 15 compatibility fixes were applied separately in #99512.

Release timeline:
 * LLVM 15 branched on Jul 26.
 * The final LLVM 15.0.0 release is scheduled for Sep 6.
 * Current nightly (1.65.0) is scheduled for Nov 3.

Changes in this PR (apart from the LLVM update):
 * Pass `--set llvm.allow-old-toolchain` for many Docker images. LLVM 16 will require GCC >= 7.1, while LLVM 15 still allows older compilers with an option. Specify the option for builders still using GCC 5.4. #95026 updated some of the used toolchains, but not all.
 * Use the `+atomics-32` target feature for thumbv6m.
 * Explicitly link libatomic when cross-compiling LLVM to 32-bit target.
 * Explicitly disable zstd support, to avoid libzstd.so dependency.

New LLVM patches ([commits](https://github.com/rust-lang/llvm-project/commits/rustc/15.0-2022-08-09)):
 * [rust-only] Fix ICE with GCC 5.4 (15be58d7f0)
 * [rust-only] Fix build with GCC 5.4 (774edc10fa)
 * ~~[rust-only] Fix build with GCC 5.2 (1a6069a7bb)~~
 * ~~[rust-only] Fix ICE with GCC 5.2 (493081f290)~~
 * ~~[rust-only] Fix build with GCC 5.2 (0fc5979d73)~~
 * [backported] Addition of `+atomics` target feature (57bdd9892d).
 * [backported] Revert compiler-rt change that broke powerpc (9c68b43915)
 * [awaiting backport] Fix RelLookupTableConverter on gnux32 (639388a05f / https://github.com/llvm/llvm-project/issues/57021)

Tested images: dist-x86_64-linux, armhf-gnu, arm-android, dist-s390x-linux, dist-x86_64-illumos, dist-x86_64-freebsd, wasm32, dist-x86_64-musl, dist-various-1, dist-riscv64-linux, dist-mips-linux, dist-mipsel-linux, dist-powerpc-linux, dist-aarch64-linux, dist-x86_64-apple, x86_64-msvc-1, x86_64-msvc-2, dist-various-2, dist-arm-linux
Tested up to the usual ipv6 error: test-various, i686-gnu, x86_64-gnu-nopt

r? `@ghost`

.github/workflows/ci.yml

@@ -389,26 +389,26 @@ jobs:
             os: windows-latest-xl
           - name: i686-mingw-1
             env:
-              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu"
+              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu --set llvm.allow-old-toolchain"
               SCRIPT: make ci-mingw-subset-1
               CUSTOM_MINGW: 1
             os: windows-latest-xl
           - name: i686-mingw-2
             env:
-              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu"
+              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu --set llvm.allow-old-toolchain"
               SCRIPT: make ci-mingw-subset-2
               CUSTOM_MINGW: 1
             os: windows-latest-xl
           - name: x86_64-mingw-1
             env:
               SCRIPT: make ci-mingw-subset-1
-              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-profiler"
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-profiler --set llvm.allow-old-toolchain"
               CUSTOM_MINGW: 1
             os: windows-latest-xl
           - name: x86_64-mingw-2
             env:
               SCRIPT: make ci-mingw-subset-2
-              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-profiler"
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-profiler --set llvm.allow-old-toolchain"
               CUSTOM_MINGW: 1
             os: windows-latest-xl
           - name: dist-x86_64-msvc
@@ -432,7 +432,7 @@ jobs:
             os: windows-latest-xl
           - name: dist-i686-mingw
             env:
-              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu --enable-full-tools --enable-profiler"
+              RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu --enable-full-tools --enable-profiler --set llvm.allow-old-toolchain"
               SCRIPT: python x.py dist
               CUSTOM_MINGW: 1
               DIST_REQUIRE_ALL_TOOLS: 1
@@ -440,7 +440,7 @@ jobs:
           - name: dist-x86_64-mingw
             env:
               SCRIPT: python x.py dist
-              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-full-tools --enable-profiler"
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-full-tools --enable-profiler --set llvm.allow-old-toolchain"
               CUSTOM_MINGW: 1
               DIST_REQUIRE_ALL_TOOLS: 1
             os: windows-latest-xl

.gitmodules

@@ -34,7 +34,7 @@
 [submodule "src/llvm-project"]
 	path = src/llvm-project
 	url = https://github.com/rust-lang/llvm-project.git
-	branch = rustc/14.0-2022-06-20
+	branch = rustc/15.0-2022-08-09
 [submodule "src/doc/embedded-book"]
 	path = src/doc/embedded-book
 	url = https://github.com/rust-embedded/book.git

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -440,6 +440,8 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
             .features
             .split(',')
             .filter(|v| !v.is_empty() && backend_feature_name(v).is_some())
+            // Drop +atomics-32 feature introduced in LLVM 15.
+            .filter(|v| *v != "+atomics-32" || get_version() >= (15, 0, 0))
             .map(String::from),
     );
 

compiler/rustc_llvm/build.rs

@@ -242,6 +242,13 @@ fn main() {
         println!("cargo:rustc-link-lib=uuid");
     } else if target.contains("netbsd") || target.contains("haiku") || target.contains("darwin") {
         println!("cargo:rustc-link-lib=z");
+    } else if target.starts_with("arm")
+        || target.starts_with("mips-")
+        || target.starts_with("mipsel-")
+        || target.starts_with("powerpc-")
+    {
+        // 32-bit targets need to link libatomic.
+        println!("cargo:rustc-link-lib=atomic");
     }
     cmd.args(&components);
 

compiler/rustc_target/src/spec/thumbv6m_none_eabi.rs

@@ -13,7 +13,9 @@ pub fn target() -> Target {
             abi: "eabi".into(),
             // The ARMv6-M architecture doesn't support unaligned loads/stores so we disable them
             // with +strict-align.
-            features: "+strict-align".into(),
+            // Also force-enable 32-bit atomics, which allows the use of atomic load/store only.
+            // The resulting atomics are ABI incompatible with atomics backed by libatomic.
+            features: "+strict-align,+atomics-32".into(),
             // There are no atomic CAS instructions available in the instruction set of the ARMv6-M
             // architecture
             atomic_cas: false,

src/bootstrap/native.rs

@@ -325,6 +325,9 @@ impl Step for Llvm {
             cfg.define("LLVM_PROFDATA_FILE", &path);
         }
 
+        // Disable zstd to avoid a dependency on libzstd.so.
+        cfg.define("LLVM_ENABLE_ZSTD", "OFF");
+
         if target != "aarch64-apple-darwin" && !target.contains("windows") {
             cfg.define("LLVM_ENABLE_ZLIB", "ON");
         } else {

src/ci/docker/host-x86_64/arm-android/Dockerfile

@@ -29,7 +29,8 @@ ENV PATH=$PATH:/android/sdk/platform-tools
 
 ENV TARGETS=arm-linux-androideabi
 
-ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/arm-14
+ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/arm-14 \
+    --set llvm.allow-old-toolchain
 
 ENV SCRIPT python3 ../x.py --stage 2 test --host='' --target $TARGETS
 

src/ci/docker/host-x86_64/dist-android/Dockerfile

@@ -32,7 +32,8 @@ ENV RUST_CONFIGURE_ARGS \
       --i686-linux-android-ndk=/android/ndk/x86-14 \
       --aarch64-linux-android-ndk=/android/ndk/arm64-21 \
       --x86_64-linux-android-ndk=/android/ndk/x86_64-21 \
-      --disable-docs
+      --disable-docs \
+      --set llvm.allow-old-toolchain
 
 ENV SCRIPT python3 ../x.py dist --host='' --target $TARGETS
 

src/ci/docker/host-x86_64/dist-i586-gnu-i586-i686-musl/Dockerfile

@@ -36,7 +36,8 @@ RUN /scripts/cmake.sh
 ENV RUST_CONFIGURE_ARGS \
       --musl-root-i586=/musl-i586 \
       --musl-root-i686=/musl-i686 \
-      --disable-docs
+      --disable-docs \
+      --set llvm.allow-old-toolchain
 
 # Newer binutils broke things on some vms/distros (i.e., linking against
 # unknown relocs disabled by the following flag), so we need to go out of our

src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile

@@ -26,5 +26,6 @@ RUN /scripts/cmake.sh
 
 ENV HOSTS=mips-unknown-linux-gnu
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs \
+    --set llvm.allow-old-toolchain
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile

@@ -25,5 +25,6 @@ RUN /scripts/cmake.sh
 
 ENV HOSTS=mips64-unknown-linux-gnuabi64
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs \
+    --set llvm.allow-old-toolchain
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile

@@ -26,5 +26,6 @@ RUN /scripts/cmake.sh
 
 ENV HOSTS=mips64el-unknown-linux-gnuabi64
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs \
+    --set llvm.allow-old-toolchain
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile

@@ -25,5 +25,6 @@ RUN /scripts/cmake.sh
 
 ENV HOSTS=mipsel-unknown-linux-gnu
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs \
+    --set llvm.allow-old-toolchain
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile

@@ -21,5 +21,6 @@ ENV \
 
 ENV HOSTS=x86_64-unknown-netbsd
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs \
+    --set llvm.allow-old-toolchain
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile

@@ -27,6 +27,7 @@ RUN mkdir -p /config
 RUN echo "[rust]" > /config/nopt-std-config.toml
 RUN echo "optimize = false" >> /config/nopt-std-config.toml
 
-ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu --disable-optimize-tests
+ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu --disable-optimize-tests \
+    --set llvm.allow-old-toolchain
 ENV SCRIPT python3 ../x.py test --stage 0 --config /config/nopt-std-config.toml library/std \
   && python3 ../x.py --stage 2 test

src/ci/docker/host-x86_64/i686-gnu/Dockerfile

@@ -23,7 +23,8 @@ RUN sh /scripts/sccache.sh
 COPY scripts/cmake.sh /scripts/
 RUN /scripts/cmake.sh
 
-ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu
+ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu \
+    --set llvm.allow-old-toolchain
 # Exclude some tests that are unlikely to be platform specific, to speed up
 # this slow job.
 ENV SCRIPT python3 ../x.py --stage 2 test \

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

@@ -26,5 +26,6 @@ RUN sh /scripts/sccache.sh
 COPY scripts/cmake.sh /scripts/
 RUN /scripts/cmake.sh
 
-ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu
+ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu \
+    --set llvm.allow-old-toolchain
 ENV RUST_CHECK_TARGET check-aux

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

@@ -22,6 +22,7 @@ RUN sh /scripts/sccache.sh
 COPY scripts/cmake.sh /scripts/
 RUN /scripts/cmake.sh
 
-ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu --set rust.ignore-git=false
+ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu --set rust.ignore-git=false \
+    --set llvm.allow-old-toolchain
 ENV SCRIPT python3 ../x.py --stage 2 test distcheck
 ENV DIST_SRC 1

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

@@ -81,6 +81,7 @@ COPY host-x86_64/x86_64-gnu-tools/browser-ui-test.version /tmp/
 RUN npm install -g browser-ui-test@$(head -n 1 /tmp/browser-ui-test.version) --unsafe-perm=true
 
 ENV RUST_CONFIGURE_ARGS \
+  --set llvm.allow-old-toolchain \
   --build=x86_64-unknown-linux-gnu \
   --save-toolstates=/tmp/toolstate/toolstates.json
 

src/ci/github-actions/ci.yml

@@ -596,14 +596,18 @@ jobs:
 
           - name: i686-mingw-1
             env:
-              RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
+              RUST_CONFIGURE_ARGS: >-
+                --build=i686-pc-windows-gnu
+                --set llvm.allow-old-toolchain
               SCRIPT: make ci-mingw-subset-1
               CUSTOM_MINGW: 1
             <<: *job-windows-xl
 
           - name: i686-mingw-2
             env:
-              RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
+              RUST_CONFIGURE_ARGS: >-
+                --build=i686-pc-windows-gnu
+                --set llvm.allow-old-toolchain
               SCRIPT: make ci-mingw-subset-2
               CUSTOM_MINGW: 1
             <<: *job-windows-xl
@@ -611,14 +615,20 @@ jobs:
           - name: x86_64-mingw-1
             env:
               SCRIPT: make ci-mingw-subset-1
-              RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu --enable-profiler
+              RUST_CONFIGURE_ARGS: >-
+                --build=x86_64-pc-windows-gnu
+                --enable-profiler
+                --set llvm.allow-old-toolchain
               CUSTOM_MINGW: 1
             <<: *job-windows-xl
 
           - name: x86_64-mingw-2
             env:
               SCRIPT: make ci-mingw-subset-2
-              RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu --enable-profiler
+              RUST_CONFIGURE_ARGS: >-
+                --build=x86_64-pc-windows-gnu
+                --enable-profiler
+                --set llvm.allow-old-toolchain
               CUSTOM_MINGW: 1
             <<: *job-windows-xl
 
@@ -663,7 +673,11 @@ jobs:
 
           - name: dist-i686-mingw
             env:
-              RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu --enable-full-tools --enable-profiler
+              RUST_CONFIGURE_ARGS: >-
+                --build=i686-pc-windows-gnu
+                --enable-full-tools
+                --enable-profiler
+                --set llvm.allow-old-toolchain
               SCRIPT: python x.py dist
               CUSTOM_MINGW: 1
               DIST_REQUIRE_ALL_TOOLS: 1
@@ -672,7 +686,11 @@ jobs:
           - name: dist-x86_64-mingw
             env:
               SCRIPT: python x.py dist
-              RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu --enable-full-tools --enable-profiler
+              RUST_CONFIGURE_ARGS: >-
+                --build=x86_64-pc-windows-gnu
+                --enable-full-tools
+                --enable-profiler
+                --set llvm.allow-old-toolchain
               CUSTOM_MINGW: 1
               DIST_REQUIRE_ALL_TOOLS: 1
             <<: *job-windows-xl

src/llvm-project

@@ -1 +1 @@
-Subproject commit 8b6b5014fdad3a750f7242a6bfdcad83619498d4
+Subproject commit e3be3f64ecac101d14ceda759ba078ad0aaf3747

src/test/run-make/coverage-llvmir/filecheck.testprog.txt

@@ -9,7 +9,7 @@ CHECK-SAME:   section "[[INSTR_PROF_COVFUN]]"[[COMDAT_IF_SUPPORTED]], align 8
 CHECK:        @__llvm_coverage_mapping = private constant
 CHECK-SAME:   section "[[INSTR_PROF_COVMAP]]", align 8
 
-WINDOWS:      @__llvm_profile_runtime = external global i32
+WINDOWS:      @__llvm_profile_runtime = external{{.*}}global i32
 
 CHECK:        @__profc__R{{[a-zA-Z0-9_]+}}testprog14will_be_called = {{private|internal}} global
 CHECK-SAME:   section "[[INSTR_PROF_CNTS]]"{{.*}}, align 8