Codegen tests for Arm Cortex-R82

This PR adds checks to the `aarch64v8r-unknown-none` target to verify that if the Cortex-R82 CPU is enabled (with `-Ctarget-cpu=cortex-r82`), that the appropriate additional AArch64 features are enabled.

This is important because Cortex-R82 is (currently) the only processor implementing Armv8-R AArch64 and it implements a number of Armv8 features over and above the baseline for the architecture. Many of these features are of interest to safety-critical firmware development (for example `FEAT_RASv1p1`, which adds support for the *RAS Common Fault Injection Model Extension*) and so we anticipate them being enabled when building such firmware.

We are offering these tests upstream in-lieu of a full Cortex-R82 specific target because we understand the Project has a preference for architecture-baseline targets over CPU-specific targets.

This PR builds on and requires https://github.com/rust-lang/rust/pull/150863, but we've pulled them out as a separate PR.

This PR was developed by Ferrous Systems on behalf of Arm. Arm is the owner of these changes.

tests/ui/asm/aarch64v8r.rs

@@ -1,11 +1,15 @@
 // Codegen test of mandatory Armv8-R AArch64 extensions
 
+// The Cortex-R82 CPU is an implementation of the Arm v8-R AArch64 ISA so
+// it also implements the ISA-level mandatory extensions. We check that with a revision
 //@ add-minicore
-//@ revisions: hf sf
+//@ revisions: hf sf r82
 //@ [hf] compile-flags: --target aarch64v8r-unknown-none
 //@ [hf] needs-llvm-components: aarch64
 //@ [sf] compile-flags: --target aarch64v8r-unknown-none-softfloat
 //@ [sf] needs-llvm-components: aarch64
+//@ [r82] compile-flags: --target aarch64v8r-unknown-none -C target-cpu=cortex-r82
+//@ [r82] needs-llvm-components: aarch64
 //@ build-pass
 //@ ignore-backends: gcc
 

tests/ui/asm/cortex-r82.rs

@@ -0,0 +1,176 @@
+// Codegen test of mandatory Cortex-R82 extensions
+
+//@ add-minicore
+//@ compile-flags: --target aarch64v8r-unknown-none -C target-cpu=cortex-r82
+//@ needs-llvm-components: aarch64
+//@ build-pass
+//@ ignore-backends: gcc
+
+#![deny(dead_code)]
+#![feature(no_core)]
+#![no_core]
+#![no_main]
+#![crate_type = "rlib"]
+
+extern crate minicore;
+use minicore::*;
+
+/* # Mandatory extensions
+ *
+ * A `//` comment indicates that the extension has no associated assembly instruction and cannot
+ * be codegen tested
+ * A `/*  */` comment indicates that the extension is being tested in the ISA level codegen test
+ * (`tests/ui/asm/aarch64v8r.rs`)
+ *
+ * ## References:
+ *
+ * - Arm Cortex-R82 Processor Technical Reference Manual Revision r3p1 (102670_0301_06_en Issue 6)
+ *   section 3.2.1 has the list of mandatory extensions
+ * - Arm Architecture Reference Manual for A-profile architecture (ARM DDI 0487) -- has the
+ *   mapping from features to instructions
+ * - Feature names in A-profile architecture (109697_0100_02_en Version 1.0) -- overview of what
+ *   each extension mean
+ * */
+pub fn mandatory_extensions() {
+    // FEAT_GICv3
+    // FEAT_GICv3p1
+    // FEAT_GICv3_TDIR
+    feat_pmuv3();
+    // FEAT_ETMv4
+    // FEAT_ETMv4p1
+    // FEAT_ETMv4p2
+    // FEAT_ETMv4p3
+    // FEAT_ETMv4p4
+    // FEAT_ETMv4p5
+    /* FEAT_RAS */
+    // FEAT_PCSRv8
+    feat_ssbs();
+    feat_ssbs2();
+    // FEAT_CSV2
+    // FEAT_CSV2_1p1
+    // FEAT_CSV3
+    feat_sb();
+    feat_specres();
+    feat_dgh();
+    // FEAT_nTLBPA
+    /* FEAT_CRC32 */
+    /* FEAT_LSE */
+    feat_rdm();
+    /* FEAT_HPDS */
+    /* FEAT_PAN */
+    // FEAT_HAFDBS
+    // FEAT_PMUv3p1
+    // FEAT_TTCNP
+    // FEAT_XNX
+    /* FEAT_UAO */
+    feat_pan2();
+    feat_dpb();
+    /* FEAT_Debugv8p2 */
+    /* FEAT_ASMv8p2 */
+    // FEAT_IESB
+    feat_fp16();
+    // FEAT_PCSRv8p2
+    feat_dotprod();
+    feat_fhm();
+    feat_dpb2();
+    /* FEAT_PAuth */
+    // FEAT_PACQARMA3
+    // FEAT_PAuth2
+    // FEAT_FPAC
+    // FEAT_FPACCOMBINE
+    // FEAT_CONSTPACFIELD
+    feat_jscvt();
+    /* FEAT_LRCPC */
+    feat_fcma();
+    // FEAT_DoPD
+    // FEAT_SEL2
+    /* FEAT_S2FWB */
+    /* FEAT_DIT */
+    /* FEAT_IDST */
+    /* FEAT_FlagM */
+    /* FEAT_LSE2 */
+    /* FEAT_LRCPC2 */
+    /* FEAT_TLBIOS */
+    /* FEAT_TLBIRANGE */
+    /* FEAT_TTL */
+    // FEAT_BBM
+    // FEAT_CNTSC
+    feat_rasv1p1();
+    // FEAT_Debugv8p4
+    feat_pmuv3p4();
+    feat_trf();
+    // FEAT_TTST
+    // FEAT_E0PD
+}
+
+fn feat_pmuv3() {
+    unsafe { asm!("mrs x0, PMCCFILTR_EL0") }
+}
+
+fn feat_ssbs() {
+    unsafe { asm!("msr SSBS, 1") }
+}
+
+fn feat_ssbs2() {
+    unsafe { asm!("mrs x0, SSBS") }
+}
+
+fn feat_sb() {
+    unsafe { asm!("sb") }
+}
+
+fn feat_specres() {
+    unsafe { asm!("cfp rctx, x0") }
+}
+
+fn feat_dgh() {
+    unsafe { asm!("dgh") }
+}
+
+fn feat_rdm() {
+    unsafe { asm!("sqrdmlah v0.4h, v1.4h, v2.4h") }
+}
+
+fn feat_pan2() {
+    unsafe { asm!("AT S1E1RP, x0") }
+}
+
+fn feat_dpb() {
+    unsafe { asm!("DC CVAP, x0") }
+}
+
+fn feat_fp16() {
+    unsafe { asm!("fmulx h0, h1, h2") }
+}
+
+fn feat_dotprod() {
+    unsafe { asm!("sdot V0.4S, V1.16B, V2.16B") }
+}
+
+fn feat_fhm() {
+    unsafe { asm!("fmlal v0.2s, v1.2h, v2.2h") }
+}
+
+fn feat_dpb2() {
+    unsafe { asm!("DC CVADP, x0") }
+}
+
+fn feat_jscvt() {
+    unsafe { asm!("fjcvtzs w0, d1") }
+}
+
+fn feat_fcma() {
+    unsafe { asm!("fcadd v0.4h, v1.4h, v2.4h, #90") }
+}
+
+fn feat_rasv1p1() {
+    unsafe { asm!("mrs x0, ERXMISC2_EL1") }
+}
+
+fn feat_pmuv3p4() {
+    unsafe { asm!("mrs x0, PMMIR_EL1") }
+}
+
+fn feat_trf() {
+    unsafe { asm!("tsb csync") }
+}