[RISCV] Imply extensions in RISCVTargetInfo::initFeatureMap

[eopXD]

Summary

Under ASTContext, clang only copies the features from the options with
Target->initFeatureMap, and no implications is done there. This makes
clang_cc1 fail to imply into zve32x for the vector extension, and test
cases will have to add -target-feature +experimental-zve32x in order
to work.

This patch fixes it.

[eopXD]

Rebase.

[eopXD]

Rebase.

[eopXD]

Rebase.

[eopXD]

Rebase.

[eopXD]

Rebase to latest main.

[eopXD]

This patch needs to be landed before D112613 because clang_cc1 needs to do correct implication from v, zve32f, zve64f and zve64d and this patch fixes the issue.

[kito-cheng]

Otherwise LGTM.

clang/lib/Basic/Targets/RISCV.cpp

235–236

Maybe update XLen based on the if condition? that might save one StringMap query.

unsigned XLen = 32;

if (getTriple().getArch() == llvm::Triple::riscv64) {
  Features["64bit"] = true;
  XLen = 64;
}

[eopXD]

Update code based on @kito-cheng 's comment.

[junparser]

@eopXD, hi, this patch make us lost +relax and -save-restore by default, would you please fix it?

[eopXD]

In D113336#3313909, @junparser wrote:

@eopXD, hi, this patch make us lost +relax and -save-restore by default, would you please fix it?

Sure, let me look into it.
Do you have an existing test case for your situation? (Or I will make one while fixing)

clang/lib/Basic/Targets/RISCV.cpp

ArrayRef<Builtin::Info> RISCVTargetInfo::getTargetBuiltins() const {
   return llvm::makeArrayRef(BuiltinInfo, clang::RISCV::LastTSBuiltin -
                                              Builtin::FirstTSBuiltin);
 }
 
 bool RISCVTargetInfo::initFeatureMap(
     llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
     const std::vector<std::string> &FeaturesVec) const {
 
-  if (getTriple().getArch() == llvm::Triple::riscv64)
+  unsigned XLen = 32;
+
+  if (getTriple().getArch() == llvm::Triple::riscv64) {
     Features["64bit"] = true;
+    XLen = 64;
+  }
+
+  auto ParseResult = llvm::RISCVISAInfo::parseFeatures(XLen, FeaturesVec);
+  if (!ParseResult) {
+    std::string Buffer;
+    llvm::raw_string_ostream OutputErrMsg(Buffer);
+    handleAllErrors(ParseResult.takeError(), [&](llvm::StringError &ErrMsg) {
+      OutputErrMsg << ErrMsg.getMessage();
+    });
+    Diags.Report(diag::err_invalid_feature_combination) << OutputErrMsg.str();
+    return false;
+  }
 
-  return TargetInfo::initFeatureMap(Features, Diags, CPU, FeaturesVec);
+  return TargetInfo::initFeatureMap(Features, Diags, CPU,
+                                    (*ParseResult)->toFeatureVector());
 }
 
 /// Return true if has this feature, need to sync with handleTargetFeatures.
 bool RISCVTargetInfo::hasFeature(StringRef Feature) const {
   bool Is64Bit = getTriple().getArch() == llvm::Triple::riscv64;
   auto Result = llvm::StringSwitch<Optional<bool>>(Feature)
                     .Case("riscv", true)
                     .Case("riscv32", !Is64Bit)

llvm/include/llvm/Support/RISCVISAInfo.h

public:
   unsigned getXLen() const { return XLen; };
   unsigned getFLen() const { return FLen; };
   unsigned getMinVLen() const { return MinVLen; }
   unsigned getMaxELen() const { return MaxELen; }
   unsigned getMaxELenFp() const { return MaxELenFp; }
 
   bool hasExtension(StringRef Ext) const;
   std::string toString() const;
+  std::vector<std::string> toFeatureVector() const;
 
   static bool isSupportedExtensionFeature(StringRef Ext);
   static bool isSupportedExtension(StringRef Ext);
   static bool isSupportedExtension(StringRef Ext, unsigned MajorVersion,
                                    unsigned MinorVersion);
 
 private:
   RISCVISAInfo(unsigned XLen)

llvm/lib/Support/RISCVISAInfo.cpp

for (auto &Ext : Exts) {
     StringRef ExtName = Ext.first;
     auto ExtInfo = Ext.second;
     Arch << LS << ExtName;
     Arch << ExtInfo.MajorVersion << "p" << ExtInfo.MinorVersion;
   }
 
   return Arch.str();
 }
+
+std::vector<std::string> RISCVISAInfo::toFeatureVector() const {
+  std::vector<std::string> FeatureVector;
+  for (auto Ext : Exts) {
+    std::string ExtName = Ext.first;
+    if (ExtName == "i") // i is not recognized in clang -cc1
+      continue;
+    std::string Feature = isExperimentalExtension(ExtName)
+                              ? "+experimental-" + ExtName
+                              : "+" + ExtName;
+    FeatureVector.push_back(Feature);
+  }
+  return FeatureVector;
+}