Auto merge of #83890 - Dylan-DPC:rollup-9fqy3fe, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #83368 (Add `download-rustc = "if-unchanged"`)
 - #83705 (Give a better error when --theme is not a CSS file)
 - #83853 (Disallow the use of high byte registes as operands on x86_64)
 - #83877 (Remove unnecessary exceptions to the platform-specific code check)
 - #83878 (Fix racing file access in tidy)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_target/src/asm/arm.rs

@@ -68,7 +68,6 @@ fn frame_pointer_r11(
     _arch: InlineAsmArch,
     has_feature: impl FnMut(&str) -> bool,
     target: &Target,
-    _allocating: bool,
 ) -> Result<(), &'static str> {
     if !frame_pointer_is_r7(has_feature, target) {
         Err("the frame pointer (r11) cannot be used as an operand for inline asm")
@@ -81,7 +80,6 @@ fn frame_pointer_r7(
     _arch: InlineAsmArch,
     has_feature: impl FnMut(&str) -> bool,
     target: &Target,
-    _allocating: bool,
 ) -> Result<(), &'static str> {
     if frame_pointer_is_r7(has_feature, target) {
         Err("the frame pointer (r7) cannot be used as an operand for inline asm")

compiler/rustc_target/src/asm/mod.rs

@@ -90,7 +90,7 @@ macro_rules! def_regs {
                 match name {
                     $(
                         $($alias)|* | $reg_name => {
-                            $($filter(_arch, &mut _has_feature, _target, false)?;)?
+                            $($filter(_arch, &mut _has_feature, _target)?;)?
                             Ok(Self::$reg)
                         }
                     )*
@@ -114,7 +114,7 @@ macro_rules! def_regs {
             #[allow(unused_imports)]
             use super::{InlineAsmReg, InlineAsmRegClass};
             $(
-                if $($filter(_arch, &mut _has_feature, _target, true).is_ok() &&)? true {
+                if $($filter(_arch, &mut _has_feature, _target).is_ok() &&)? true {
                     if let Some(set) = _map.get_mut(&InlineAsmRegClass::$arch($arch_regclass::$class)) {
                         set.insert(InlineAsmReg::$arch($arch_reg::$reg));
                     }

compiler/rustc_target/src/asm/riscv.rs

@@ -52,7 +52,6 @@ fn not_e(
     _arch: InlineAsmArch,
     mut has_feature: impl FnMut(&str) -> bool,
     _target: &Target,
-    _allocating: bool,
 ) -> Result<(), &'static str> {
     if has_feature("e") {
         Err("register can't be used with the `e` target feature")

compiler/rustc_target/src/asm/x86.rs

@@ -133,7 +133,6 @@ fn x86_64_only(
     arch: InlineAsmArch,
     _has_feature: impl FnMut(&str) -> bool,
     _target: &Target,
-    _allocating: bool,
 ) -> Result<(), &'static str> {
     match arch {
         InlineAsmArch::X86 => Err("register is only available on x86_64"),
@@ -146,13 +145,9 @@ fn high_byte(
     arch: InlineAsmArch,
     _has_feature: impl FnMut(&str) -> bool,
     _target: &Target,
-    allocating: bool,
 ) -> Result<(), &'static str> {
     match arch {
-        InlineAsmArch::X86_64 if allocating => {
-            // The error message isn't actually used...
-            Err("high byte registers are not allocated by reg_byte")
-        }
+        InlineAsmArch::X86_64 => Err("high byte registers cannot be used as an operand on x86_64"),
         _ => Ok(()),
     }
 }

config.toml.example

@@ -373,7 +373,9 @@ changelog-seen = 2
 # Whether to download the stage 1 and 2 compilers from CI.
 # This is mostly useful for tools; if you have changes to `compiler/` they will be ignored.
 #
-# FIXME: currently, this also uses the downloaded compiler for stage0, but that causes unnecessary rebuilds.
+# You can set this to "if-unchanged" to only download if `compiler/` has not been modified.
+#
+# FIXME(#82739): currently, this also uses the downloaded compiler for stage0, but that causes unnecessary rebuilds.
 #download-rustc = false
 
 # Number of codegen units to use for each compiler invocation. A value of 0

src/bootstrap/bootstrap.py

@@ -644,8 +644,10 @@ def fix_bin_or_dylib(self, fname, rpath_libz=False):
     # If `download-rustc` is set, download the most recent commit with CI artifacts
     def maybe_download_ci_toolchain(self):
         # If `download-rustc` is not set, default to rebuilding.
-        if self.get_toml("download-rustc", section="rust") != "true":
+        download_rustc = self.get_toml("download-rustc", section="rust")
+        if download_rustc is None or download_rustc == "false":
             return None
+        assert download_rustc == "true" or download_rustc == "if-unchanged", download_rustc
 
         # Handle running from a directory other than the top level
         rev_parse = ["git", "rev-parse", "--show-toplevel"]
@@ -660,6 +662,8 @@ def maybe_download_ci_toolchain(self):
         # Warn if there were changes to the compiler since the ancestor commit.
         status = subprocess.call(["git", "diff-index", "--quiet", commit, "--", compiler])
         if status != 0:
+            if download_rustc == "if-unchanged":
+                return None
             print("warning: `download-rustc` is enabled, but there are changes to compiler/")
 
         if self.verbose:
@@ -1175,6 +1179,8 @@ def bootstrap(help_triggered):
     env["RUSTC_BOOTSTRAP"] = '1'
     if toml_path:
         env["BOOTSTRAP_CONFIG"] = toml_path
+    if build.rustc_commit is not None:
+        env["BOOTSTRAP_DOWNLOAD_RUSTC"] = '1'
     run(args, env=env, verbose=build.verbose)
 
 

src/bootstrap/config.rs

@@ -510,7 +510,8 @@ struct Rust {
     new_symbol_mangling: Option<bool>,
     profile_generate: Option<String>,
     profile_use: Option<String>,
-    download_rustc: Option<bool>,
+    // ignored; this is set from an env var set by bootstrap.py
+    download_rustc: Option<StringOrBool>,
 }
 
 /// TOML representation of how each build target is configured.
@@ -852,7 +853,7 @@ impl Config {
             config.rust_codegen_units_std = rust.codegen_units_std.map(threads_from_config);
             config.rust_profile_use = flags.rust_profile_use.or(rust.profile_use);
             config.rust_profile_generate = flags.rust_profile_generate.or(rust.profile_generate);
-            config.download_rustc = rust.download_rustc.unwrap_or(false);
+            config.download_rustc = env::var("BOOTSTRAP_DOWNLOAD_RUSTC").as_deref() == Ok("1");
         } else {
             config.rust_profile_use = flags.rust_profile_use;
             config.rust_profile_generate = flags.rust_profile_generate;

src/doc/unstable-book/src/library-features/asm.md

@@ -501,7 +501,7 @@ Here is the list of currently supported register classes:
 | x86 | `reg` | `ax`, `bx`, `cx`, `dx`, `si`, `di`, `r[8-15]` (x86-64 only) | `r` |
 | x86 | `reg_abcd` | `ax`, `bx`, `cx`, `dx` | `Q` |
 | x86-32 | `reg_byte` | `al`, `bl`, `cl`, `dl`, `ah`, `bh`, `ch`, `dh` | `q` |
-| x86-64 | `reg_byte` | `al`, `bl`, `cl`, `dl`, `sil`, `dil`, `r[8-15]b`, `ah`\*, `bh`\*, `ch`\*, `dh`\* | `q` |
+| x86-64 | `reg_byte`\* | `al`, `bl`, `cl`, `dl`, `sil`, `dil`, `r[8-15]b` | `q` |
 | x86 | `xmm_reg` | `xmm[0-7]` (x86) `xmm[0-15]` (x86-64) | `x` |
 | x86 | `ymm_reg` | `ymm[0-7]` (x86) `ymm[0-15]` (x86-64) | `x` |
 | x86 | `zmm_reg` | `zmm[0-7]` (x86) `zmm[0-31]` (x86-64) | `v` |
@@ -532,7 +532,7 @@ Here is the list of currently supported register classes:
 
 > **Note**: On x86 we treat `reg_byte` differently from `reg` because the compiler can allocate `al` and `ah` separately whereas `reg` reserves the whole register.
 >
-> Note #2: On x86-64 the high byte registers (e.g. `ah`) are only available when used as an explicit register. Specifying the `reg_byte` register class for an operand will always allocate a low byte register.
+> Note #2: On x86-64 the high byte registers (e.g. `ah`) are not available in the `reg_byte` register class.
 >
 > Note #3: NVPTX doesn't have a fixed register set, so named registers are not supported.
 >

src/librustdoc/config.rs

@@ -484,7 +484,9 @@ impl Options {
                     return Err(1);
                 }
                 if theme_file.extension() != Some(OsStr::new("css")) {
-                    diag.struct_err(&format!("invalid argument: \"{}\"", theme_s)).emit();
+                    diag.struct_err(&format!("invalid argument: \"{}\"", theme_s))
+                        .help("arguments to --theme must have a .css extension")
+                        .emit();
                     return Err(1);
                 }
                 let (success, ret) = theme::test_theme_against(&theme_file, &paths, &diag);

src/test/assembly/asm/x86-types.rs

@@ -748,10 +748,11 @@ check_reg!(eax_f64 f64 "eax" "mov");
 // CHECK: #NO_APP
 check_reg!(eax_ptr ptr "eax" "mov");
 
-// CHECK-LABEL: ah_byte:
-// CHECK: #APP
-// CHECK: mov ah, ah
-// CHECK: #NO_APP
+// i686-LABEL: ah_byte:
+// i686: #APP
+// i686: mov ah, ah
+// i686: #NO_APP
+#[cfg(i686)]
 check_reg!(ah_byte i8 "ah" "mov");
 
 // CHECK-LABEL: xmm0_i32:

src/test/rustdoc-ui/invalid-theme-name.rs

@@ -0,0 +1,3 @@
+// compile-flags:--theme {{src-base}}/invalid-theme-name.rs
+// error-pattern: invalid argument
+// error-pattern: must have a .css extension

src/test/rustdoc-ui/invalid-theme-name.stderr

@@ -0,0 +1,4 @@
+error: invalid argument: "$DIR/invalid-theme-name.rs"
+   |
+   = help: arguments to --theme must have a .css extension
+

src/test/ui/asm/bad-reg.rs

@@ -37,6 +37,8 @@ fn main() {
         //~^ ERROR invalid register `mm0`: MMX registers are not currently supported as operands
         asm!("", in("k0") foo);
         //~^ ERROR invalid register `k0`: the k0 AVX mask register cannot be used as an operand
+        asm!("", in("ah") foo);
+        //~^ ERROR invalid register `ah`: high byte registers cannot be used as an operand
 
         // Explicit register conflicts
         // (except in/lateout which don't conflict)

src/test/ui/asm/bad-reg.stderr

@@ -94,49 +94,55 @@ error: invalid register `k0`: the k0 AVX mask register cannot be used as an oper
 LL |         asm!("", in("k0") foo);
    |                  ^^^^^^^^^^^^
 
+error: invalid register `ah`: high byte registers cannot be used as an operand on x86_64
+  --> $DIR/bad-reg.rs:40:18
+   |
+LL |         asm!("", in("ah") foo);
+   |                  ^^^^^^^^^^^^
+
 error: register `al` conflicts with register `ax`
-  --> $DIR/bad-reg.rs:44:33
+  --> $DIR/bad-reg.rs:46:33
    |
 LL |         asm!("", in("eax") foo, in("al") bar);
    |                  -------------  ^^^^^^^^^^^^ register `al`
    |                  |
    |                  register `ax`
 
 error: register `ax` conflicts with register `ax`
-  --> $DIR/bad-reg.rs:46:33
+  --> $DIR/bad-reg.rs:48:33
    |
 LL |         asm!("", in("rax") foo, out("rax") bar);
    |                  -------------  ^^^^^^^^^^^^^^ register `ax`
    |                  |
    |                  register `ax`
    |
 help: use `lateout` instead of `out` to avoid conflict
-  --> $DIR/bad-reg.rs:46:18
+  --> $DIR/bad-reg.rs:48:18
    |
 LL |         asm!("", in("rax") foo, out("rax") bar);
    |                  ^^^^^^^^^^^^^
 
 error: register `ymm0` conflicts with register `xmm0`
-  --> $DIR/bad-reg.rs:49:34
+  --> $DIR/bad-reg.rs:51:34
    |
 LL |         asm!("", in("xmm0") foo, in("ymm0") bar);
    |                  --------------  ^^^^^^^^^^^^^^ register `ymm0`
    |                  |
    |                  register `xmm0`
 
 error: register `ymm0` conflicts with register `xmm0`
-  --> $DIR/bad-reg.rs:51:34
+  --> $DIR/bad-reg.rs:53:34
    |
 LL |         asm!("", in("xmm0") foo, out("ymm0") bar);
    |                  --------------  ^^^^^^^^^^^^^^^ register `ymm0`
    |                  |
    |                  register `xmm0`
    |
 help: use `lateout` instead of `out` to avoid conflict
-  --> $DIR/bad-reg.rs:51:18
+  --> $DIR/bad-reg.rs:53:18
    |
 LL |         asm!("", in("xmm0") foo, out("ymm0") bar);
    |                  ^^^^^^^^^^^^^^
 
-error: aborting due to 18 previous errors
+error: aborting due to 19 previous errors
 

src/tools/compiletest/src/runtest.rs

@@ -1909,8 +1909,7 @@ impl<'test> TestCx<'test> {
         } else {
             Command::new(&self.config.rustdoc_path.clone().expect("no rustdoc built yet"))
         };
-        // FIXME Why is -L here?
-        rustc.arg(input_file); //.arg("-L").arg(&self.config.build_base);
+        rustc.arg(input_file);
 
         // Use a single thread for efficiency and a deterministic error message order
         rustc.arg("-Zthreads=1");

src/tools/tidy/src/lib.rs

@@ -53,6 +53,7 @@ pub mod unstable_book;
 
 fn filter_dirs(path: &Path) -> bool {
     let skip = [
+        "tidy-test-file",
         "compiler/rustc_codegen_cranelift",
         "src/llvm-project",
         "library/backtrace",

src/tools/tidy/src/pal.rs

@@ -40,35 +40,20 @@ const EXCEPTION_PATHS: &[&str] = &[
     "library/panic_abort",
     "library/panic_unwind",
     "library/unwind",
-    // black_box implementation is LLVM-version specific and it uses
-    // target_os to tell targets with different LLVM-versions apart
-    // (e.g. `wasm32-unknown-emscripten` vs `wasm32-unknown-unknown`):
-    "library/core/src/hint.rs",
     "library/std/src/sys/", // Platform-specific code for std lives here.
     // This has the trailing slash so that sys_common is not excepted.
     "library/std/src/os", // Platform-specific public interfaces
     "library/rtstartup",  // Not sure what to do about this. magic stuff for mingw
-    // temporary exceptions
-    "library/std/src/lib.rs",
-    "library/std/src/path.rs",
-    "library/std/src/f32.rs",
-    "library/std/src/f64.rs",
     // Integration test for platform-specific run-time feature detection:
     "library/std/tests/run-time-detect.rs",
     "library/std/src/net/test.rs",
     "library/std/src/net/addr",
     "library/std/src/net/udp",
-    "library/std/src/sys_common/mod.rs",
-    "library/std/src/sys_common/net.rs",
-    "library/std/src/sys_common/backtrace.rs",
     "library/std/src/sys_common/remutex.rs",
     "library/std/src/sync/mutex.rs",
     "library/std/src/sync/rwlock.rs",
-    // panic_unwind shims
-    "library/std/src/panicking.rs",
     "library/term", // Not sure how to make this crate portable, but test crate needs it.
     "library/test", // Probably should defer to unstable `std::sys` APIs.
-    "library/std/src/sync/mpsc", // some tests are only run on non-emscripten
     // std testing crates, okay for now at least
     "library/core/tests",
     "library/alloc/tests/lib.rs",
@@ -79,13 +64,6 @@ const EXCEPTION_PATHS: &[&str] = &[
     // we must use `#[cfg(windows)]` to conditionally compile the
     // correct `VaList` structure for windows.
     "library/core/src/ffi.rs",
-    // non-std crates
-    "src/test",
-    "src/tools",
-    "src/librustc",
-    "src/librustdoc",
-    "src/librustc_ast",
-    "src/bootstrap",
 ];
 
 pub fn check(path: &Path, bad: &mut bool) {