[AArch64] Add ability to list extensions enabled for a target (#95805)

This introduces the new `--print-enabled-extensions` command line option
to AArch64, which prints the list of extensions that are enabled for the
target specified by the combination of `--target`/`-march`/`-mcpu`
values.

The goal of the this option is both to enable the manual inspection of
the enabled extensions by users and to enhance the testability of
architecture versions and CPU targets implemented in the compiler.

As part of this change, a new field for `FEAT_*` architecture feature
names was added to the TableGen entries. The output of the existing
`--print-supported-extensions` option was updated accordingly to show
these in a separate column.

Author: pratlucas

clang/include/clang/Driver/Options.td

@@ -5710,6 +5710,11 @@ def print_supported_extensions : Flag<["-", "--"], "print-supported-extensions">
   Visibility<[ClangOption, CC1Option, CLOption]>,
   HelpText<"Print supported -march extensions (RISC-V, AArch64 and ARM only)">,
   MarshallingInfoFlag<FrontendOpts<"PrintSupportedExtensions">>;
+def print_enabled_extensions : Flag<["-", "--"], "print-enabled-extensions">,
+  Visibility<[ClangOption, CC1Option, CLOption]>,
+  HelpText<"Print the extensions enabled by the given target and -march/-mcpu options."
+           " (AArch64 only)">,
+  MarshallingInfoFlag<FrontendOpts<"PrintEnabledExtensions">>;
 def : Flag<["-"], "mcpu=help">, Alias<print_supported_cpus>;
 def : Flag<["-"], "mtune=help">, Alias<print_supported_cpus>;
 def time : Flag<["-"], "time">,

clang/include/clang/Frontend/FrontendOptions.h

@@ -306,6 +306,10 @@ class FrontendOptions {
   LLVM_PREFERRED_TYPE(bool)
   unsigned PrintSupportedExtensions : 1;
 
+  /// Print the extensions enabled for the current target.
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned PrintEnabledExtensions : 1;
+
   /// Show the -version text.
   LLVM_PREFERRED_TYPE(bool)
   unsigned ShowVersion : 1;

clang/lib/Driver/Driver.cpp

@@ -363,6 +363,7 @@ phases::ID Driver::getFinalPhase(const DerivedArgList &DAL,
     // -{fsyntax-only,-analyze,emit-ast} only run up to the compiler.
   } else if ((PhaseArg = DAL.getLastArg(options::OPT_fsyntax_only)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_print_supported_cpus)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT_print_enabled_extensions)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_module_file_info)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_verify_pch)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_rewrite_objc)) ||
@@ -2163,7 +2164,8 @@ bool Driver::HandleImmediateArgs(const Compilation &C) {
   if (C.getArgs().hasArg(options::OPT_v) ||
       C.getArgs().hasArg(options::OPT__HASH_HASH_HASH) ||
       C.getArgs().hasArg(options::OPT_print_supported_cpus) ||
-      C.getArgs().hasArg(options::OPT_print_supported_extensions)) {
+      C.getArgs().hasArg(options::OPT_print_supported_extensions) ||
+      C.getArgs().hasArg(options::OPT_print_enabled_extensions)) {
     PrintVersion(C, llvm::errs());
     SuppressMissingInputWarning = true;
   }
@@ -4347,13 +4349,14 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
   }
 
   for (auto Opt : {options::OPT_print_supported_cpus,
-                   options::OPT_print_supported_extensions}) {
+                   options::OPT_print_supported_extensions,
+                   options::OPT_print_enabled_extensions}) {
     // If --print-supported-cpus, -mcpu=? or -mtune=? is specified, build a
     // custom Compile phase that prints out supported cpu models and quits.
     //
-    // If --print-supported-extensions is specified, call the helper function
-    // RISCVMarchHelp in RISCVISAInfo.cpp that prints out supported extensions
-    // and quits.
+    // If either --print-supported-extensions or --print-enabled-extensions is
+    // specified, call the corresponding helper function that prints out the
+    // supported/enabled extensions and quits.
     if (Arg *A = Args.getLastArg(Opt)) {
       if (Opt == options::OPT_print_supported_extensions &&
           !C.getDefaultToolChain().getTriple().isRISCV() &&
@@ -4363,6 +4366,12 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
             << "--print-supported-extensions";
         return;
       }
+      if (Opt == options::OPT_print_enabled_extensions &&
+          !C.getDefaultToolChain().getTriple().isAArch64()) {
+        C.getDriver().Diag(diag::err_opt_not_valid_on_target)
+            << "--print-enabled-extensions";
+        return;
+      }
 
       // Use the -mcpu=? flag as the dummy input to cc1.
       Actions.clear();

clang/lib/Driver/ToolChain.cpp

@@ -195,11 +195,11 @@ static void getAArch64MultilibFlags(const Driver &D,
                                        UnifiedFeatures.end());
   std::vector<std::string> MArch;
   for (const auto &Ext : AArch64::Extensions)
-    if (FeatureSet.contains(Ext.Feature))
-      MArch.push_back(Ext.Name.str());
+    if (FeatureSet.contains(Ext.PosTargetFeature))
+      MArch.push_back(Ext.UserVisibleName.str());
   for (const auto &Ext : AArch64::Extensions)
-    if (FeatureSet.contains(Ext.NegFeature))
-      MArch.push_back(("no" + Ext.Name).str());
+    if (FeatureSet.contains(Ext.NegTargetFeature))
+      MArch.push_back(("no" + Ext.UserVisibleName).str());
   StringRef ArchName;
   for (const auto &ArchInfo : AArch64::ArchInfos)
     if (FeatureSet.contains(ArchInfo->ArchFeature))

clang/lib/Driver/ToolChains/Clang.cpp

@@ -1524,7 +1524,7 @@ static void CollectARMPACBTIOptions(const ToolChain &TC, const ArgList &Args,
       auto isPAuthLR = [](const char *member) {
         llvm::AArch64::ExtensionInfo pauthlr_extension =
             llvm::AArch64::getExtensionByID(llvm::AArch64::AEK_PAUTHLR);
-        return pauthlr_extension.Feature == member;
+        return pauthlr_extension.PosTargetFeature == member;
       };
 
       if (std::any_of(CmdArgs.begin(), CmdArgs.end(), isPAuthLR))

clang/test/CodeGen/aarch64-targetattr.c

@@ -196,14 +196,14 @@ void minusarch() {}
 // CHECK: attributes #[[ATTR1]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+crc,+fp-armv8,+fullfp16,+lse,+neon,+ras,+rdm,+sve,+v8.1a,+v8.2a,+v8a" }
 // CHECK: attributes #[[ATTR2]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+crc,+fp-armv8,+fullfp16,+lse,+neon,+ras,+rdm,+sve,+sve2,+v8.1a,+v8.2a,+v8a" }
 // CHECK: attributes #[[ATTR3]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+bf16,+complxnum,+crc,+dotprod,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+ras,+rcpc,+rdm,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a" }
-// CHECK: attributes #[[ATTR4]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="cortex-a710" "target-features"="+bf16,+complxnum,+crc,+dotprod,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+mte,+neon,+pauth,+perfmon,+ras,+rcpc,+rdm,+sb,+sve,+sve2,+sve2-bitperm,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8a,+v9a" }
+// CHECK: attributes #[[ATTR4]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="cortex-a710" "target-features"="+bf16,+complxnum,+crc,+dotprod,+ete,+flagm,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+mte,+neon,+pauth,+perfmon,+ras,+rcpc,+rdm,+sb,+sve,+sve2,+sve2-bitperm,+trbe,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8a,+v9a" }
 // CHECK: attributes #[[ATTR5]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "tune-cpu"="cortex-a710" }
-// CHECK: attributes #[[ATTR6]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+fp-armv8,+neon,+v8a" }
+// CHECK: attributes #[[ATTR6]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+ete,+fp-armv8,+neon,+trbe,+v8a" }
 // CHECK: attributes #[[ATTR7]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "tune-cpu"="generic" }
 // CHECK: attributes #[[ATTR8]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="neoverse-n1" "target-features"="+aes,+crc,+dotprod,+fp-armv8,+fullfp16,+lse,+neon,+perfmon,+ras,+rcpc,+rdm,+sha2,+spe,+ssbs,+v8.1a,+v8.2a,+v8a" "tune-cpu"="cortex-a710" }
 // CHECK: attributes #[[ATTR9]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+fullfp16,+sve" "tune-cpu"="cortex-a710" }
-// CHECK: attributes #[[ATTR10]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="neoverse-v1" "target-features"="+aes,+bf16,+complxnum,+crc,+dotprod,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+rand,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8a" }
-// CHECK: attributes #[[ATTR11]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="neoverse-v1" "target-features"="+aes,+bf16,+complxnum,+crc,+dotprod,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+rand,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+spe,+ssbs,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8a,-sve" }
+// CHECK: attributes #[[ATTR10]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="neoverse-v1" "target-features"="+aes,+bf16,+ccdp,+complxnum,+crc,+dotprod,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+rand,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8a" }
+// CHECK: attributes #[[ATTR11]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="neoverse-v1" "target-features"="+aes,+bf16,+ccdp,+complxnum,+crc,+dotprod,+fp-armv8,+fp16fml,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+rand,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+spe,+ssbs,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8a,-sve" }
 // CHECK: attributes #[[ATTR12]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+fullfp16,+sve" }
 // CHECK: attributes #[[ATTR13]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+fullfp16" }
 // CHECK: attributes #[[ATTR14]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="neoverse-n1" "target-features"="+aes,+bf16,+complxnum,+crc,+dotprod,+fp-armv8,+fullfp16,+i8mm,+jsconv,+lse,+neon,+pauth,+perfmon,+ras,+rcpc,+rdm,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a" "tune-cpu"="cortex-a710" }