[llvm] [RISCV][TableGen] Generate RISCVTargetParser.inc from the new RISCVExtension tblgen information. (PR #89335)

[Francesco Petrogalli via llvm-commits]

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@@ -17,34 +17,34 @@
 
 using namespace llvm;
 
-using ISAInfoTy = llvm::Expected<std::unique_ptr<RISCVISAInfo>>;
-
 // We can generate march string from target features as what has been described
 // in RISC-V ISA specification (version 20191213) 'Chapter 27. ISA Extension
 // Naming Conventions'.
 //
 // This is almost the same as RISCVFeatures::parseFeatureBits, except that we
 // get feature name from feature records instead of feature bits.
-static std::string getMArch(const Record &Rec) {
-  std::vector<std::string> FeatureVector;
+static void printMArch(raw_ostream &OS, const Record &Rec) {
+  std::map<std::string, std::pair<unsigned, unsigned>,
+           RISCVISAInfo::ExtensionComparator>
+      Extensions;
   unsigned XLen = 32;
 
   // Convert features to FeatureVector.
   for (auto *Feature : Rec.getValueAsListOfDefs("Features")) {
     StringRef FeatureName = Feature->getValueAsString("Name");
-    if (llvm::RISCVISAInfo::isSupportedExtensionFeature(FeatureName))
-      FeatureVector.push_back((Twine("+") + FeatureName).str());
-    else if (FeatureName == "64bit")
+    if (Feature->isSubClassOf("RISCVExtension")) {
+      unsigned Major = Feature->getValueAsInt("MajorVersion");
+      unsigned Minor = Feature->getValueAsInt("MinorVersion");
+      Extensions.try_emplace(FeatureName.str(), Major, Minor);
+    } else if (FeatureName == "64bit")
       XLen = 64;
   }
 
-  ISAInfoTy ISAInfo = llvm::RISCVISAInfo::parseFeatures(XLen, FeatureVector);
-  if (!ISAInfo)
-    report_fatal_error("Invalid features");
+  OS << "rv" << XLen;
 
-  // RISCVISAInfo::toString will generate a march string with all the extensions
-  // we have added to it.
-  return (*ISAInfo)->toString();
+  ListSeparator LS("_");
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fpetrogalli wrote:

oh, nice! I didn't know about this trick :)

https://github.com/llvm/llvm-project/pull/89335