Rollup merge of #133463 - taiki-e:aarch64-asm-x18, r=Amanieu

Fix handling of x18 in AArch64 inline assembly on ohos/trusty or with -Zfixed-x18

Currently AArch64 inline assembly allows using x18 on ohos/trusty or with -Zfixed-x18.

https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_target/src/asm/aarch64.rs#L74-L76

However, x18 is reserved in these environments and should not be allowed in the input/output operands of inline assemblies as it is in Android, Windows, etc..

https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_ohos.rs#L19
https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_target/src/spec/targets/aarch64_unknown_trusty.rs#L18
https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_codegen_llvm/src/llvm_util.rs#L764-L771

(As for ohos, +reserve-x18 is [redundant](https://github.com/llvm/llvm-project/commit/c417b7a695704d5bc3be23f34d1bfa505f5172de#diff-0ddf23e0bf2b28b2d05f842f087d1e6f694e8e06d1765e8d0f10d47fddcdff9c) since https://github.com/rust-lang/rust/commit/7a966b918870485e9b364e77f50c511f8c2cc275 that starting using llvm's ohos targets. So removed it from target-spec.)

This fix may potentially break the code for tier 2 target (aarch64-unknown-linux-ohos). (As for others, aarch64-unknown-trusty is tier 3 and -Zfixed-x18 is unstable so breaking them should be fine.)
However, in any case, it seems suspicious that the code that is broken by this was sound.

r? `@Amanieu`

`@rustbot` label O-AArch64 +A-inline-assembly

2 files changed, 51 insertions, 36 deletions

diff --git a/tests/codegen/asm/aarch64-clobbers.rs b/tests/codegen/asm/aarch64-clobbers.rs
new file mode 100644
index 00000000000..900e6629fd2
--- /dev/null
+++ b/tests/codegen/asm/aarch64-clobbers.rs
@@ -0,0 +1,51 @@
+//@ revisions: aarch64 aarch64_fixed_x18 aarch64_no_x18 aarch64_reserve_x18 arm64ec
+//@[aarch64] compile-flags: --target aarch64-unknown-linux-gnu
+//@[aarch64] needs-llvm-components: aarch64
+//@[aarch64_fixed_x18] compile-flags: --target aarch64-unknown-linux-gnu -Zfixed-x18
+//@[aarch64_fixed_x18] needs-llvm-components: aarch64
+//@[aarch64_no_x18] compile-flags: --target aarch64-pc-windows-msvc
+//@[aarch64_no_x18] needs-llvm-components: aarch64
+// aarch64-unknown-trusty uses aarch64-unknown-unknown-musl which doesn't
+// reserve x18 by default as llvm_target, and pass +reserve-x18 in target-spec.
+//@[aarch64_reserve_x18] compile-flags: --target aarch64-unknown-trusty
+//@[aarch64_reserve_x18] needs-llvm-components: aarch64
+//@[arm64ec] compile-flags: --target arm64ec-pc-windows-msvc
+//@[arm64ec] needs-llvm-components: aarch64
+// ignore-tidy-linelength
+
+#![crate_type = "rlib"]
+#![feature(no_core, rustc_attrs, lang_items)]
+#![no_core]
+
+#[lang = "sized"]
+trait Sized {}
+
+#[rustc_builtin_macro]
+macro_rules! asm {
+    () => {};
+}
+
+// CHECK-LABEL: @cc_clobber
+// CHECK: call void asm sideeffect "", "~{cc}"()
+#[no_mangle]
+pub unsafe fn cc_clobber() {
+    asm!("", options(nostack, nomem));
+}
+
+// CHECK-LABEL: @no_clobber
+// CHECK: call void asm sideeffect "", ""()
+#[no_mangle]
+pub unsafe fn no_clobber() {
+    asm!("", options(nostack, nomem, preserves_flags));
+}
+
+// CHECK-LABEL: @clobber_abi
+// aarch64: asm sideeffect "", "={w0},={w1},={w2},={w3},={w4},={w5},={w6},={w7},={w8},={w9},={w10},={w11},={w12},={w13},={w14},={w15},={w16},={w17},={w18},={w30},={q0},={q1},={q2},={q3},={q4},={q5},={q6},={q7},={q8},={q9},={q10},={q11},={q12},={q13},={q14},={q15},={q16},={q17},={q18},={q19},={q20},={q21},={q22},={q23},={q24},={q25},={q26},={q27},={q28},={q29},={q30},={q31},~{p0},~{p1},~{p2},~{p3},~{p4},~{p5},~{p6},~{p7},~{p8},~{p9},~{p10},~{p11},~{p12},~{p13},~{p14},~{p15},~{ffr}"()
+// aarch64_fixed_x18: asm sideeffect "", "={w0},={w1},={w2},={w3},={w4},={w5},={w6},={w7},={w8},={w9},={w10},={w11},={w12},={w13},={w14},={w15},={w16},={w17},={w30},={q0},={q1},={q2},={q3},={q4},={q5},={q6},={q7},={q8},={q9},={q10},={q11},={q12},={q13},={q14},={q15},={q16},={q17},={q18},={q19},={q20},={q21},={q22},={q23},={q24},={q25},={q26},={q27},={q28},={q29},={q30},={q31},~{p0},~{p1},~{p2},~{p3},~{p4},~{p5},~{p6},~{p7},~{p8},~{p9},~{p10},~{p11},~{p12},~{p13},~{p14},~{p15},~{ffr}"()
+// aarch64_no_x18: asm sideeffect "", "={w0},={w1},={w2},={w3},={w4},={w5},={w6},={w7},={w8},={w9},={w10},={w11},={w12},={w13},={w14},={w15},={w16},={w17},={w30},={q0},={q1},={q2},={q3},={q4},={q5},={q6},={q7},={q8},={q9},={q10},={q11},={q12},={q13},={q14},={q15},={q16},={q17},={q18},={q19},={q20},={q21},={q22},={q23},={q24},={q25},={q26},={q27},={q28},={q29},={q30},={q31},~{p0},~{p1},~{p2},~{p3},~{p4},~{p5},~{p6},~{p7},~{p8},~{p9},~{p10},~{p11},~{p12},~{p13},~{p14},~{p15},~{ffr}"()
+// aarch64_reserve_x18: asm sideeffect "", "={w0},={w1},={w2},={w3},={w4},={w5},={w6},={w7},={w8},={w9},={w10},={w11},={w12},={w13},={w14},={w15},={w16},={w17},={w30},={q0},={q1},={q2},={q3},={q4},={q5},={q6},={q7},={q8},={q9},={q10},={q11},={q12},={q13},={q14},={q15},={q16},={q17},={q18},={q19},={q20},={q21},={q22},={q23},={q24},={q25},={q26},={q27},={q28},={q29},={q30},={q31},~{p0},~{p1},~{p2},~{p3},~{p4},~{p5},~{p6},~{p7},~{p8},~{p9},~{p10},~{p11},~{p12},~{p13},~{p14},~{p15},~{ffr}"()
+// arm64ec: asm sideeffect "", "={w0},={w1},={w2},={w3},={w4},={w5},={w6},={w7},={w8},={w9},={w10},={w11},={w12},={w15},={w16},={w17},={w30},={q0},={q1},={q2},={q3},={q4},={q5},={q6},={q7},={q8},={q9},={q10},={q11},={q12},={q13},={q14},={q15}"()
+#[no_mangle]
+pub unsafe fn clobber_abi() {
+    asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
+}
diff --git a/tests/codegen/asm/arm64ec-clobbers.rs b/tests/codegen/asm/arm64ec-clobbers.rs
deleted file mode 100644
index 80059331642..00000000000
--- a/tests/codegen/asm/arm64ec-clobbers.rs
+++ /dev/null
@@ -1,36 +0,0 @@
-//@ assembly-output: emit-asm
-//@ compile-flags: --target arm64ec-pc-windows-msvc
-//@ needs-llvm-components: aarch64
-
-#![crate_type = "rlib"]
-#![feature(no_core, rustc_attrs, lang_items)]
-#![no_core]
-
-#[lang = "sized"]
-trait Sized {}
-
-#[rustc_builtin_macro]
-macro_rules! asm {
-    () => {};
-}
-
-// CHECK-LABEL: @cc_clobber
-// CHECK: call void asm sideeffect "", "~{cc}"()
-#[no_mangle]
-pub unsafe fn cc_clobber() {
-    asm!("", options(nostack, nomem));
-}
-
-// CHECK-LABEL: @no_clobber
-// CHECK: call void asm sideeffect "", ""()
-#[no_mangle]
-pub unsafe fn no_clobber() {
-    asm!("", options(nostack, nomem, preserves_flags));
-}
-
-// CHECK-LABEL: @clobber_abi
-// CHECK: asm sideeffect "", "={w0},={w1},={w2},={w3},={w4},={w5},={w6},={w7},={w8},={w9},={w10},={w11},={w12},={w15},={w16},={w17},={w30},={q0},={q1},={q2},={q3},={q4},={q5},={q6},={q7},={q8},={q9},={q10},={q11},={q12},={q13},={q14},={q15}"()
-#[no_mangle]
-pub unsafe fn clobber_abi() {
-    asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
-}