Auto merge of rust-lang#133634 - matthiaskrgr:rollup-v7m4j2k, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#131323 (Support `clobber_abi` in AVR inline assembly)
 - rust-lang#131718 ([rustdoc] Change impl items indent)
 - rust-lang#133565 (chore: fix 404 status URL)
 - rust-lang#133575 (Fix typo in RELEASES.md)
 - rust-lang#133577 (Document s390x machine access via community cloud)
 - rust-lang#133584 (Update more 2024 tests to remove -Zunstable-options)
 - rust-lang#133592 (Misc: better instructions for envrc, ignore `/build` instead of `build/`)

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

Author: bors

.gitignore

@@ -46,8 +46,7 @@ no_llvm_build
 /inst/
 /llvm/
 /mingw-build/
-build/
-!/compiler/rustc_mir_build/src/build/
+/build
 /build-rust-analyzer/
 /dist/
 /unicode-downloads

RELEASES.md

@@ -43,7 +43,7 @@ Libraries
 - [Document that `catch_unwind` can deal with foreign exceptions without UB, although the exact behavior is unspecified.](https://github.com/rust-lang/rust/pull/128321)
 - [Implement `Default` for `HashMap`/`HashSet` iterators that don't already have it.](https://github.com/rust-lang/rust/pull/128711)
 - [Bump Unicode to version 16.0.0.](https://github.com/rust-lang/rust/pull/130183)
-- [Change documentation of `ptr::add`/`sub` to not claim equivalence with `offset`.](https://github.com/rust-lang/rust/pull/130229).
+- [Change documentation of `ptr::add`/`sub` to not claim equivalence with `offset`.](https://github.com/rust-lang/rust/pull/130229)
 
 
 <a id="1.83.0-Stabilized-APIs"></a>

compiler/rustc_mir_build/src/build/expr/as_rvalue.rs

@@ -231,7 +231,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             if range.start <= range.end { BinOp::BitAnd } else { BinOp::BitOr };
 
                         let mut comparer = |range: u128, bin_op: BinOp| -> Place<'tcx> {
-                            // We can use `ty::TypingEnv::fully_monomorphized()`` here
+                            // We can use `ty::TypingEnv::fully_monomorphized()` here
                             // as we only need it to compute the layout of a primitive.
                             let range_val = Const::from_bits(
                                 this.tcx,

compiler/rustc_target/src/asm/avr.rs

@@ -105,7 +105,12 @@ def_regs! {
         #error = ["SP", "SPL", "SPH"] =>
             "the stack pointer cannot be used as an operand for inline asm",
         #error = ["r0", "r1", "r1r0"] =>
-            "r0 and r1 are not available due to an issue in LLVM",
+            "LLVM reserves r0 (scratch register) and r1 (zero register)",
+            // If this changes within LLVM, the compiler might use the registers
+            // in the future. This must be reflected in the set of clobbered
+            // registers, else the clobber ABI implementation is *unsound*, as
+            // this generates invalid code (register is not marked as clobbered
+            // but may change the register content).
     }
 }
 

compiler/rustc_target/src/asm/mod.rs

@@ -928,6 +928,7 @@ pub enum InlineAsmClobberAbi {
     AArch64,
     AArch64NoX18,
     Arm64EC,
+    Avr,
     RiscV,
     RiscVE,
     LoongArch,
@@ -986,6 +987,10 @@ impl InlineAsmClobberAbi {
                 }),
                 _ => Err(&["C", "system", "efiapi"]),
             },
+            InlineAsmArch::Avr => match name {
+                "C" | "system" => Ok(InlineAsmClobberAbi::Avr),
+                _ => Err(&["C", "system"]),
+            },
             InlineAsmArch::LoongArch64 => match name {
                 "C" | "system" => Ok(InlineAsmClobberAbi::LoongArch),
                 _ => Err(&["C", "system"]),
@@ -1133,6 +1138,23 @@ impl InlineAsmClobberAbi {
                     d24, d25, d26, d27, d28, d29, d30, d31,
                 }
             },
+            InlineAsmClobberAbi::Avr => clobbered_regs! {
+                Avr AvrInlineAsmReg {
+                    // The list of "Call-Used Registers" according to
+                    // https://gcc.gnu.org/wiki/avr-gcc#Call-Used_Registers
+
+                    // Clobbered registers available in inline assembly
+                    r18, r19, r20, r21, r22, r23, r24, r25, r26, r27, r30, r31,
+                    // As per the AVR-GCC-ABI documentation linked above, the R0
+                    // register is a clobbered register as well. Since we don't
+                    // allow the usage of R0 in inline assembly, nothing has to
+                    // be done here.
+                    // Likewise, the T-flag in the SREG should be clobbered, but
+                    // this is not necessary to be listed here, since the SREG
+                    // is considered clobbered anyways unless `preserve_flags`
+                    // is used.
+                }
+            },
             InlineAsmClobberAbi::RiscV => clobbered_regs! {
                 RiscV RiscVInlineAsmReg {
                     // ra

src/doc/rustc/src/platform-support/armeb-unknown-linux-gnueabi.md

@@ -16,7 +16,7 @@ BE8 architecture is the default big-endian architecture for Arm since [Armv6](ht
 The target is cross-compiled. This target supports `std` in the normal way (indeed only nominal changes are required from the standard Arm configuration).
 
 ## Target definition
-The target definition can be seen [here](https://github.com/rust-lang/rust/tree/master/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs). In particular, it should be noted that the `features` specify that this target is built for the Armv8 core. Though this can likely be modified as required.
+The target definition can be seen [here](https://github.com/rust-lang/rust/blob/master/compiler/rustc_target/src/spec/targets/armeb_unknown_linux_gnueabi.rs). In particular, it should be noted that the `features` specify that this target is built for the Armv8 core. Though this can likely be modified as required.
 
 ## Building the target
 Because it is Tier 3, rust does not yet ship pre-compiled artifacts for this target.

src/doc/rustc/src/platform-support/s390x-unknown-linux-gnu.md

@@ -64,6 +64,22 @@ There are no special requirements for testing and running the target.
 For testing cross builds on the host, please refer to the "Cross-compilation
 toolchains and C code" section below.
 
+If you want to do native testing but do not have your own s390x
+machine, there are several options how to get access to one:
+
+* The [IBM LinuxONE Community Cloud][cloud-community] provides a
+  self-service portal where you can create s390x virtual machine
+  instances.  These are intended for temporary use (limited to 120 days).
+
+* The [IBM LinuxONE Open Source Cloud][cloud-opensource] provides
+  permanent access to s390x machines.  This requires approval by IBM,
+  which will normally be granted if you're planning to use the machine
+  to work on an open-source project that is relevant to the IBM Z
+  ecosystem - the Rust compiler would certainly qualify.
+
+[cloud-community]: https://linuxone.cloud.marist.edu/
+[cloud-opensource]: https://community.ibm.com/zsystems/form/l1cc-oss-vm-request/
+
 ## Cross-compilation toolchains and C code
 
 Rust code built using the target is compatible with C code compiled with

src/librustdoc/html/static/css/rustdoc.css

@@ -36,6 +36,8 @@ xmlns="http://www.w3.org/2000/svg" fill="black" height="18px">\
 	--button-border-radius: 2px;
 	--toolbar-button-border-radius: 6px;
 	--code-block-border-radius: 6px;
+	--impl-items-indent: 0.3em;
+	--docblock-indent: 24px;
 }
 
 /* See FiraSans-LICENSE.txt for the Fira Sans license. */
@@ -909,7 +911,7 @@ both the code example and the line numbers, so we need to remove the radius in t
 .docblock h6 { font-size: 0.875rem; }
 
 .docblock {
-	margin-left: 24px;
+	margin-left: var(--docblock-indent);
 	position: relative;
 }
 
@@ -982,7 +984,11 @@ div.where {
 
 .item-info {
 	display: block;
-	margin-left: 24px;
+	margin-left: var(--docblock-indent);
+}
+.impl-items > .item-info {
+	/* Margin of docblocks + margin of impl block items. */
+	margin-left: calc(var(--docblock-indent) + var(--impl-items-indent));
 }
 
 .item-info code {
@@ -2166,6 +2172,15 @@ details.toggle > summary:not(.hideme)::before {
 	left: -24px;
 }
 
+/* We indent items of an impl block to have a visual marker that these items are part
+	of this impl block. */
+.impl-items > *:not(.item-info),
+/* We also indent the first top doc comment the same to still keep an indent on the
+	doc block while aligning it with the impl block items. */
+.implementors-toggle > .docblock {
+	margin-left: var(--impl-items-indent);
+}
+
 details.big-toggle > summary:not(.hideme)::before {
 	left: -34px;
 	top: 9px;
@@ -2255,6 +2270,10 @@ If you update this line, then you also need to update the line with the same war
 in src-script.js and main.js
 */
 @media (max-width: 700px) {
+	:root {
+		--impl-items-indent: 0.7em;
+	}
+
 	/* When linking to an item with an `id` (for instance, by clicking a link in the sidebar,
 	   or visiting a URL with a fragment like `#method.new`, we don't want the item to be obscured
 	   by the topbar. Anything with an `id` gets scroll-margin-top equal to .mobile-topbar's size.
@@ -2454,19 +2473,20 @@ in src-script.js and main.js
 		padding-top: 0;
 	}
 
-	/* Position of the "[-]" element. */
-	details.toggle:not(.top-doc) > summary, .impl-items > section  {
+	details.implementors-toggle:not(.top-doc) > summary  {
 		margin-left: 10px;
 	}
-	.impl-items > details.toggle > summary:not(.hideme)::before,
-	#main-content > details.toggle:not(.top-doc) > summary::before,
-	#main-content > div > details.toggle > summary::before {
-		left: -11px;
+
+	.impl-items > details.toggle > summary:not(.hideme)::before {
+		left: -20px;
 	}
 
 	/* Align summary-nested and unnested item-info gizmos. */
+	summary > .item-info {
+		margin-left: 10px;
+	}
 	.impl-items > .item-info {
-		margin-left: 34px;
+		margin-left: calc(var(--impl-items-indent) + 10px);
 	}
 
 	.src nav.sub {
@@ -2500,24 +2520,24 @@ in src-script.js and main.js
 }
 
 @media print {
+	:root {
+		--docblock-indent: 0;
+	}
+
 	nav.sidebar, nav.sub, .out-of-band, a.src, #copy-path,
 	details.toggle[open] > summary::before, details.toggle > summary::before,
 	details.toggle.top-doc > summary {
 		display: none;
 	}
 
-	.docblock {
-		margin-left: 0;
-	}
-
 	main {
 		padding: 10px;
 	}
 }
 
 @media (max-width: 464px) {
-	.docblock {
-		margin-left: 12px;
+	:root {
+		--docblock-indent: 12px;
 	}
 
 	.docblock code {

src/tools/nix-dev-shell/envrc-flake

@@ -1,7 +1,7 @@
 # If you want to use this as an .envrc file to create a shell with necessery components 
 # to develop rustc, use the following command in the root of the rusr checkout:
 #	
-# ln -s ./src/tools/nix-dev-shell/envrc-flake ./.envrc && echo .envrc >> .git/info/exclude
+# ln -s ./src/tools/nix-dev-shell/envrc-flake ./.envrc && nix flake update --flake ./src/tools/nix-dev-shell && echo .envrc >> .git/info/exclude
 
 if nix flake show path:./src/tools/nix-dev-shell &> /dev/null; then
   use flake path:./src/tools/nix-dev-shell

tests/codegen/asm/avr-clobbers.rs

@@ -0,0 +1,43 @@
+//@ assembly-output: emit-asm
+//@ compile-flags: --target avr-unknown-gnu-atmega328
+//@ needs-llvm-components: avr
+
+#![crate_type = "rlib"]
+#![feature(no_core, rustc_attrs, lang_items, asm_experimental_arch)]
+#![no_core]
+
+#[lang = "sized"]
+trait Sized {}
+
+#[rustc_builtin_macro]
+macro_rules! asm {
+    () => {};
+}
+
+// CHECK-LABEL: @sreg_is_clobbered
+// CHECK: void asm sideeffect "", "~{sreg}"()
+#[no_mangle]
+pub unsafe fn sreg_is_clobbered() {
+    asm!("", options(nostack, nomem));
+}
+
+// CHECK-LABEL: @sreg_is_not_clobbered_if_preserve_flags_is_used
+// CHECK: void asm sideeffect "", ""()
+#[no_mangle]
+pub unsafe fn sreg_is_not_clobbered_if_preserve_flags_is_used() {
+    asm!("", options(nostack, nomem, preserves_flags));
+}
+
+// CHECK-LABEL: @clobber_abi
+// CHECK: asm sideeffect "", "={r18},={r19},={r20},={r21},={r22},={r23},={r24},={r25},={r26},={r27},={r30},={r31},~{sreg}"()
+#[no_mangle]
+pub unsafe fn clobber_abi() {
+    asm!("", clobber_abi("C"), options(nostack, nomem));
+}
+
+// CHECK-LABEL: @clobber_abi_with_preserved_flags
+// CHECK: asm sideeffect "", "={r18},={r19},={r20},={r21},={r22},={r23},={r24},={r25},={r26},={r27},={r30},={r31}"()
+#[no_mangle]
+pub unsafe fn clobber_abi_with_preserved_flags() {
+    asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
+}