Auto merge of rust-lang#2878 - RalfJung:rustup, r=RalfJung

Rustup

Author: bors

.github/workflows/ci.yml

@@ -42,24 +42,20 @@ jobs:
       TOOLSTATE_REPO: "https://github.com/rust-lang-nursery/rust-toolstate"
       CACHE_DOMAIN: ci-caches.rust-lang.org
     if: "github.event_name == 'pull_request'"
-    continue-on-error: "${{ matrix.tidy }}"
+    continue-on-error: "${{ matrix.name == 'mingw-check-tidy' }}"
     strategy:
       matrix:
         include:
           - name: mingw-check
-            tidy: false
             os: ubuntu-20.04-16core-64gb
             env: {}
           - name: mingw-check-tidy
-            tidy: true
             os: ubuntu-20.04-16core-64gb
             env: {}
           - name: x86_64-gnu-llvm-14
-            tidy: false
             os: ubuntu-20.04-16core-64gb
             env: {}
           - name: x86_64-gnu-tools
-            tidy: false
             os: ubuntu-20.04-16core-64gb
             env: {}
     timeout-minutes: 600
@@ -98,9 +94,6 @@ jobs:
       - name: show the current environment
         run: src/ci/scripts/dump-environment.sh
         if: success() && !env.SKIP_JOB
-      - name: install awscli
-        run: src/ci/scripts/install-awscli.sh
-        if: success() && !env.SKIP_JOB
       - name: install sccache
         run: src/ci/scripts/install-sccache.sh
         if: success() && !env.SKIP_JOB
@@ -170,6 +163,7 @@ jobs:
       TOOLSTATE_PUBLISH: 1
       CACHES_AWS_ACCESS_KEY_ID: AKIA46X5W6CZI5DHEBFL
       ARTIFACTS_AWS_ACCESS_KEY_ID: AKIA46X5W6CZN24CBO55
+      AWS_REGION: us-west-1
       CACHE_DOMAIN: ci-caches.rust-lang.org
     if: "github.event_name == 'push' && github.ref == 'refs/heads/auto' && github.repository == 'rust-lang-ci/rust'"
     strategy:
@@ -521,9 +515,6 @@ jobs:
       - name: show the current environment
         run: src/ci/scripts/dump-environment.sh
         if: success() && !env.SKIP_JOB
-      - name: install awscli
-        run: src/ci/scripts/install-awscli.sh
-        if: success() && !env.SKIP_JOB
       - name: install sccache
         run: src/ci/scripts/install-sccache.sh
         if: success() && !env.SKIP_JOB
@@ -593,6 +584,7 @@ jobs:
       TOOLSTATE_PUBLISH: 1
       CACHES_AWS_ACCESS_KEY_ID: AKIA46X5W6CZI5DHEBFL
       ARTIFACTS_AWS_ACCESS_KEY_ID: AKIA46X5W6CZN24CBO55
+      AWS_REGION: us-west-1
       CACHE_DOMAIN: ci-caches.rust-lang.org
     if: "github.event_name == 'push' && (github.ref == 'refs/heads/try' || github.ref == 'refs/heads/try-perf') && github.repository == 'rust-lang-ci/rust'"
     strategy:
@@ -637,9 +629,6 @@ jobs:
       - name: show the current environment
         run: src/ci/scripts/dump-environment.sh
         if: success() && !env.SKIP_JOB
-      - name: install awscli
-        run: src/ci/scripts/install-awscli.sh
-        if: success() && !env.SKIP_JOB
       - name: install sccache
         run: src/ci/scripts/install-sccache.sh
         if: success() && !env.SKIP_JOB
@@ -706,6 +695,7 @@ jobs:
       TOOLSTATE_PUBLISH: 1
       CACHES_AWS_ACCESS_KEY_ID: AKIA46X5W6CZI5DHEBFL
       ARTIFACTS_AWS_ACCESS_KEY_ID: AKIA46X5W6CZN24CBO55
+      AWS_REGION: us-west-1
       CACHE_DOMAIN: ci-caches.rust-lang.org
     if: "github.event_name == 'push' && github.ref == 'refs/heads/master' && github.repository == 'rust-lang-ci/rust'"
     steps:

Cargo.lock

@@ -577,7 +577,7 @@ checksum = "8a2dd5a6fe8c6e3502f568a6353e5273bbb15193ad9a89e457b9970798efbea1"
 
 [[package]]
 name = "clippy"
-version = "0.1.70"
+version = "0.1.71"
 dependencies = [
  "clap 4.2.1",
  "clippy_lints",
@@ -619,7 +619,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_lints"
-version = "0.1.70"
+version = "0.1.71"
 dependencies = [
  "arrayvec",
  "cargo_metadata 0.15.3",
@@ -643,7 +643,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_utils"
-version = "0.1.70"
+version = "0.1.71"
 dependencies = [
  "arrayvec",
  "if_chain",
@@ -969,7 +969,7 @@ checksum = "a0afaad2b26fa326569eb264b1363e8ae3357618c43982b3f285f0774ce76b69"
 
 [[package]]
 name = "declare_clippy_lint"
-version = "0.1.70"
+version = "0.1.71"
 dependencies = [
  "itertools",
  "quote",

compiler/rustc_abi/src/layout.rs

@@ -729,42 +729,73 @@ pub trait LayoutCalculator {
             align = align.max(AbiAndPrefAlign::new(repr_align));
         }
 
-        let optimize = !repr.inhibit_union_abi_opt();
+        // If all the non-ZST fields have the same ABI and union ABI optimizations aren't
+        // disabled, we can use that common ABI for the union as a whole.
+        struct AbiMismatch;
+        let mut common_non_zst_abi_and_align = if repr.inhibit_union_abi_opt() {
+            // Can't optimize
+            Err(AbiMismatch)
+        } else {
+            Ok(None)
+        };
+
         let mut size = Size::ZERO;
-        let mut abi = Abi::Aggregate { sized: true };
         let only_variant = &variants[FIRST_VARIANT];
         for field in only_variant {
             assert!(field.0.is_sized());
+
             align = align.max(field.align());
+            size = cmp::max(size, field.size());
 
-            // If all non-ZST fields have the same ABI, forward this ABI
-            if optimize && !field.0.is_zst() {
+            if field.0.is_zst() {
+                // Nothing more to do for ZST fields
+                continue;
+            }
+
+            if let Ok(common) = common_non_zst_abi_and_align {
                 // Discard valid range information and allow undef
-                let field_abi = match field.abi() {
-                    Abi::Scalar(x) => Abi::Scalar(x.to_union()),
-                    Abi::ScalarPair(x, y) => Abi::ScalarPair(x.to_union(), y.to_union()),
-                    Abi::Vector { element: x, count } => {
-                        Abi::Vector { element: x.to_union(), count }
-                    }
-                    Abi::Uninhabited | Abi::Aggregate { .. } => Abi::Aggregate { sized: true },
-                };
+                let field_abi = field.abi().to_union();
 
-                if size == Size::ZERO {
-                    // first non ZST: initialize 'abi'
-                    abi = field_abi;
-                } else if abi != field_abi {
-                    // different fields have different ABI: reset to Aggregate
-                    abi = Abi::Aggregate { sized: true };
+                if let Some((common_abi, common_align)) = common {
+                    if common_abi != field_abi {
+                        // Different fields have different ABI: disable opt
+                        common_non_zst_abi_and_align = Err(AbiMismatch);
+                    } else {
+                        // Fields with the same non-Aggregate ABI should also
+                        // have the same alignment
+                        if !matches!(common_abi, Abi::Aggregate { .. }) {
+                            assert_eq!(
+                                common_align,
+                                field.align().abi,
+                                "non-Aggregate field with matching ABI but differing alignment"
+                            );
+                        }
+                    }
+                } else {
+                    // First non-ZST field: record its ABI and alignment
+                    common_non_zst_abi_and_align = Ok(Some((field_abi, field.align().abi)));
                 }
             }
-
-            size = cmp::max(size, field.size());
         }
 
         if let Some(pack) = repr.pack {
             align = align.min(AbiAndPrefAlign::new(pack));
         }
 
+        // If all non-ZST fields have the same ABI, we may forward that ABI
+        // for the union as a whole, unless otherwise inhibited.
+        let abi = match common_non_zst_abi_and_align {
+            Err(AbiMismatch) | Ok(None) => Abi::Aggregate { sized: true },
+            Ok(Some((abi, _))) => {
+                if abi.inherent_align(dl).map(|a| a.abi) != Some(align.abi) {
+                    // Mismatched alignment (e.g. union is #[repr(packed)]): disable opt
+                    Abi::Aggregate { sized: true }
+                } else {
+                    abi
+                }
+            }
+        };
+
         Some(LayoutS {
             variants: Variants::Single { index: FIRST_VARIANT },
             fields: FieldsShape::Union(NonZeroUsize::new(only_variant.len())?),

compiler/rustc_abi/src/lib.rs

@@ -1272,6 +1272,50 @@ impl Abi {
     pub fn is_scalar(&self) -> bool {
         matches!(*self, Abi::Scalar(_))
     }
+
+    /// Returns the fixed alignment of this ABI, if any is mandated.
+    pub fn inherent_align<C: HasDataLayout>(&self, cx: &C) -> Option<AbiAndPrefAlign> {
+        Some(match *self {
+            Abi::Scalar(s) => s.align(cx),
+            Abi::ScalarPair(s1, s2) => s1.align(cx).max(s2.align(cx)),
+            Abi::Vector { element, count } => {
+                cx.data_layout().vector_align(element.size(cx) * count)
+            }
+            Abi::Uninhabited | Abi::Aggregate { .. } => return None,
+        })
+    }
+
+    /// Returns the fixed size of this ABI, if any is mandated.
+    pub fn inherent_size<C: HasDataLayout>(&self, cx: &C) -> Option<Size> {
+        Some(match *self {
+            Abi::Scalar(s) => {
+                // No padding in scalars.
+                s.size(cx)
+            }
+            Abi::ScalarPair(s1, s2) => {
+                // May have some padding between the pair.
+                let field2_offset = s1.size(cx).align_to(s2.align(cx).abi);
+                (field2_offset + s2.size(cx)).align_to(self.inherent_align(cx)?.abi)
+            }
+            Abi::Vector { element, count } => {
+                // No padding in vectors, except possibly for trailing padding
+                // to make the size a multiple of align (e.g. for vectors of size 3).
+                (element.size(cx) * count).align_to(self.inherent_align(cx)?.abi)
+            }
+            Abi::Uninhabited | Abi::Aggregate { .. } => return None,
+        })
+    }
+
+    /// Discard validity range information and allow undef.
+    pub fn to_union(&self) -> Self {
+        assert!(self.is_sized());
+        match *self {
+            Abi::Scalar(s) => Abi::Scalar(s.to_union()),
+            Abi::ScalarPair(s1, s2) => Abi::ScalarPair(s1.to_union(), s2.to_union()),
+            Abi::Vector { element, count } => Abi::Vector { element: element.to_union(), count },
+            Abi::Uninhabited | Abi::Aggregate { .. } => Abi::Aggregate { sized: true },
+        }
+    }
 }
 
 #[derive(PartialEq, Eq, Hash, Clone, Debug)]

compiler/rustc_ast/src/ast.rs

@@ -1821,6 +1821,8 @@ pub enum LitKind {
     /// A byte string (`b"foo"`). Not stored as a symbol because it might be
     /// non-utf8, and symbols only allow utf8 strings.
     ByteStr(Lrc<[u8]>, StrStyle),
+    /// A C String (`c"foo"`). Guaranteed to only have `\0` at the end.
+    CStr(Lrc<[u8]>, StrStyle),
     /// A byte char (`b'f'`).
     Byte(u8),
     /// A character literal (`'a'`).
@@ -1875,6 +1877,7 @@ impl LitKind {
             // unsuffixed variants
             LitKind::Str(..)
             | LitKind::ByteStr(..)
+            | LitKind::CStr(..)
             | LitKind::Byte(..)
             | LitKind::Char(..)
             | LitKind::Int(_, LitIntType::Unsuffixed)

compiler/rustc_ast/src/token.rs

@@ -74,6 +74,8 @@ pub enum LitKind {
     StrRaw(u8), // raw string delimited by `n` hash symbols
     ByteStr,
     ByteStrRaw(u8), // raw byte string delimited by `n` hash symbols
+    CStr,
+    CStrRaw(u8),
     Err,
 }
 
@@ -141,6 +143,10 @@ impl fmt::Display for Lit {
                 delim = "#".repeat(n as usize),
                 string = symbol
             )?,
+            CStr => write!(f, "c\"{symbol}\"")?,
+            CStrRaw(n) => {
+                write!(f, "cr{delim}\"{symbol}\"{delim}", delim = "#".repeat(n as usize))?
+            }
             Integer | Float | Bool | Err => write!(f, "{symbol}")?,
         }
 
@@ -170,6 +176,7 @@ impl LitKind {
             Float => "float",
             Str | StrRaw(..) => "string",
             ByteStr | ByteStrRaw(..) => "byte string",
+            CStr | CStrRaw(..) => "C string",
             Err => "error",
         }
     }