[AArch64][Clang] Adjust default features for v8.9-A/v9.4-A in clang driver

[pratlucas]

Summary

Update the clang driver to include the following features as default for
the v8.9-A/v9.4-A architecture versions:

• FEAT_SPECRES2
• FEAT_CSSC
• FEAT_RASv2

Patch by Sam Elliott.

[dmgreen]

Do you know why this code is in the Driver? I would have expected mandatory features to be added to the AARCH64_ARCH in AArch64TargetParser.td. I don't think they are then needed in the driver.

I can put up a patch to show what I mean, as I think the same applies to i8mm/bf16 and hbc/mops.

[dmgreen]

I've put up D141518 to move the existing features. Let me know what you think

[tmatheson]

I agree the approach in D141518 makes more sense

[pratlucas]

Updated to use the same approach as D141518.

[tmatheson]

clang/test/Driver/aarch64-cssc.c

11

Missing -###?

[pratlucas]

clang/test/Driver/aarch64-cssc.c

11

That's a consequence of the approach from D141518. The target features now go into IR attributes instead.

clang/test/Driver/aarch64-cssc.c

 // Test that target feature cssc is implemented and available correctly
-// RUN: %clang -### -target aarch64-none-none-eabi                         %s 2>&1 | FileCheck %s --check-prefix=ABSENT_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.8-a+cssc   %s 2>&1 | FileCheck %s
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.9-a        %s 2>&1 | FileCheck %s --check-prefix=ABSENT_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.8-a+cssc   %s 2>&1 | FileCheck %s
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.9-a+nocssc %s 2>&1 | FileCheck %s --check-prefix=NO_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.3-a+cssc   %s 2>&1 | FileCheck %s
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.4-a        %s 2>&1 | FileCheck %s --check-prefix=ABSENT_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.3-a+cssc   %s 2>&1 | FileCheck %s
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.4-a+nocssc %s 2>&1 | FileCheck %s --check-prefix=NO_CSSC
+// FEAT_CSSC is a required part of v8.9a/v9.4a and optional from v8.7a/v9.3a onwards.
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi                         %s 2>&1 | FileCheck %s --check-prefix=ABSENT_CSSC
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv8.7-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv8.9-a        %s 2>&1 | FileCheck %s
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv8.9-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv8.9-a+nocssc %s 2>&1 | FileCheck %s --check-prefix=NO_CSSC
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv9.2-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv9.4-a        %s 2>&1 | FileCheck %s
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv9.4-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -S -o - -emit-llvm -target aarch64-none-none-eabi -march=armv9.4-a+nocssc %s 2>&1 | FileCheck %s --check-prefix=NO_CSSC
 
-// CHECK: "-target-feature" "+cssc"
-// NO_CSSC: "-target-feature" "-cssc"
-// ABSENT_CSSC-NOT: "-target-feature" "+cssc"
-// ABSENT_CSSC-NOT: "-target-feature" "-cssc"
+// CHECK: "target-features"="{{.*}},+cssc
+// NO_CSSC: "target-features"="{{.*}},-cssc
+// ABSENT_CSSC-NOT: "target-features"="{{.*}},+cssc
+// ABSENT_CSSC-NOT: "target-features"="{{.*}},-cssc
+void test() {}

llvm/include/llvm/TargetParser/AArch64TargetParser.h

 inline constexpr ArchInfo ARMV8_2A  = { VersionTuple{8, 2}, AProfile, "armv8.2-a", "+v8.2a", (ARMV8_1A.DefaultExts | AArch64::AEK_RAS)};
 inline constexpr ArchInfo ARMV8_3A  = { VersionTuple{8, 3}, AProfile, "armv8.3-a", "+v8.3a", (ARMV8_2A.DefaultExts | AArch64::AEK_RCPC)};
 inline constexpr ArchInfo ARMV8_4A  = { VersionTuple{8, 4}, AProfile, "armv8.4-a", "+v8.4a", (ARMV8_3A.DefaultExts | AArch64::AEK_DOTPROD)};
 inline constexpr ArchInfo ARMV8_5A  = { VersionTuple{8, 5}, AProfile, "armv8.5-a", "+v8.5a", (ARMV8_4A.DefaultExts)};
 constexpr unsigned BaseNoCrypto = ARMV8_5A.DefaultExts ^ AArch64::AEK_CRYPTO; // 8.6 onwards has no AEK_CRYPTO
 inline constexpr ArchInfo ARMV8_6A  = { VersionTuple{8, 6}, AProfile, "armv8.6-a", "+v8.6a", (BaseNoCrypto | AArch64::AEK_SM4 | AArch64::AEK_SHA3 | AArch64::AEK_BF16 | AArch64::AEK_SHA2 | AArch64::AEK_AES | AArch64::AEK_I8MM)};
 inline constexpr ArchInfo ARMV8_7A  = { VersionTuple{8, 7}, AProfile, "armv8.7-a", "+v8.7a", (ARMV8_6A.DefaultExts)};
 inline constexpr ArchInfo ARMV8_8A  = { VersionTuple{8, 8}, AProfile, "armv8.8-a", "+v8.8a", (ARMV8_7A.DefaultExts | AArch64::AEK_MOPS | AArch64::AEK_HBC)};
-inline constexpr ArchInfo ARMV8_9A  = { VersionTuple{8, 9}, AProfile, "armv8.9-a", "+v8.9a", (ARMV8_8A.DefaultExts)};
+inline constexpr ArchInfo ARMV8_9A  = { VersionTuple{8, 9}, AProfile, "armv8.9-a", "+v8.9a", (ARMV8_8A.DefaultExts | AArch64::AEK_SPECRES2 | AArch64::AEK_CSSC | AArch64::AEK_RASv2)};
 inline constexpr ArchInfo ARMV9A    = { VersionTuple{9, 0}, AProfile, "armv9-a", "+v9a", (BaseNoCrypto | AArch64::AEK_FP16 | AArch64::AEK_SVE | AArch64::AEK_SVE2)};
 inline constexpr ArchInfo ARMV9_1A  = { VersionTuple{9, 1}, AProfile, "armv9.1-a", "+v9.1a", (ARMV9A.DefaultExts | AArch64::AEK_BF16 | AArch64::AEK_I8MM)};
 inline constexpr ArchInfo ARMV9_2A  = { VersionTuple{9, 2}, AProfile, "armv9.2-a", "+v9.2a", (ARMV9_1A.DefaultExts)};
 inline constexpr ArchInfo ARMV9_3A  = { VersionTuple{9, 3}, AProfile, "armv9.3-a", "+v9.3a", (ARMV9_2A.DefaultExts | AArch64::AEK_MOPS | AArch64::AEK_HBC)};
-inline constexpr ArchInfo ARMV9_4A  = { VersionTuple{9, 4}, AProfile, "armv9.4-a", "+v9.4a", (ARMV9_3A.DefaultExts)};
+inline constexpr ArchInfo ARMV9_4A  = { VersionTuple{9, 4}, AProfile, "armv9.4-a", "+v9.4a", (ARMV9_3A.DefaultExts | AArch64::AEK_SPECRES2 | AArch64::AEK_CSSC | AArch64::AEK_RASv2)};
 // For v8-R, we do not enable crypto and align with GCC that enables a more minimal set of optional architecture extensions.
 inline constexpr ArchInfo ARMV8R    = { VersionTuple{8, 0}, RProfile, "armv8-r", "+v8r", ((BaseNoCrypto ^ AArch64::AEK_LSE) | AArch64::AEK_SSBS | AArch64::AEK_FP16 | AArch64::AEK_FP16FML | AArch64::AEK_SB), };
 // clang-format on
 
 // The set of all architectures
 static constexpr std::array<const ArchInfo *, 17> ArchInfos = {
     &INVALID,  &ARMV8A,   &ARMV8_1A, &ARMV8_2A, &ARMV8_3A, &ARMV8_4A,
     &ARMV8_5A, &ARMV8_6A, &ARMV8_7A, &ARMV8_8A, &ARMV8_9A, &ARMV9A,