[RISCV] Improve error message when the extension is not supported (llvm#83989)

If the "march" has some extension with version that is not supported, it
returns the error message like: "error: invalid arch name 'some_arch',
unsupported version number 2.0 for extension 'some_arch'", which is not
precise enough, it should return the message that only tells users "the
extension is not supported".

Author: 4vtomat

clang/test/Driver/riscv-arch.c

@@ -306,7 +306,7 @@
 // RUN: not %clang --target=riscv32-unknown-elf -march=rv32ist2p0 -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-SMINOR0 %s
 // RV32-SMINOR0: error: invalid arch name 'rv32ist2p0',
-// RV32-SMINOR0: unsupported version number 2.0 for extension 'st'
+// RV32-SMINOR0: unsupported standard supervisor-level extension 'st'
 
 // RUN: not %clang --target=riscv32-unknown-elf -march=rv32ixabc_ -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-XSEP %s
@@ -397,7 +397,7 @@
 
 // RUN: not %clang --target=riscv32-unknown-elf -march=rv32izbb1p0zbs1p0 -menable-experimental-extensions -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-EXPERIMENTAL-ZBB-ZBS-UNDERSCORE %s
-// RV32-EXPERIMENTAL-ZBB-ZBS-UNDERSCORE: error: invalid arch name 'rv32izbb1p0zbs1p0', unsupported version number 1.0 for extension 'zbb1p0zbs'
+// RV32-EXPERIMENTAL-ZBB-ZBS-UNDERSCORE: error: invalid arch name 'rv32izbb1p0zbs1p0', unsupported standard user-level extension 'zbb1p0zbs'
 
 // RUN: %clang --target=riscv32-unknown-elf -march=rv32izba1p0 -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-ZBA %s

llvm/lib/Support/RISCVISAInfo.cpp

@@ -531,6 +531,17 @@ std::vector<std::string> RISCVISAInfo::toFeatures(bool AddAllExtensions,
   return Features;
 }
 
+static Error getStringErrorForInvalidExt(std::string_view ExtName) {
+  if (ExtName.size() == 1) {
+    return createStringError(errc::invalid_argument,
+                             "unsupported standard user-level extension '" +
+                                 ExtName + "'");
+  }
+  return createStringError(errc::invalid_argument,
+                           "unsupported " + getExtensionTypeDesc(ExtName) +
+                               " '" + ExtName + "'");
+}
+
 // Extensions may have a version number, and may be separated by
 // an underscore '_' e.g.: rv32i2_m2.
 // Version number is divided into major and minor version numbers,
@@ -629,6 +640,9 @@ static Error getExtensionVersion(StringRef Ext, StringRef In, unsigned &Major,
   if (RISCVISAInfo::isSupportedExtension(Ext, Major, Minor))
     return Error::success();
 
+  if (!RISCVISAInfo::isSupportedExtension(Ext))
+    return getStringErrorForInvalidExt(Ext);
+
   std::string Error = "unsupported version number " + std::string(MajorStr);
   if (!MinorStr.empty())
     Error += "." + MinorStr.str();
@@ -965,16 +979,8 @@ RISCVISAInfo::parseArchString(StringRef Arch, bool EnableExperimentalExtension,
     const std::string &ExtName = SeenExtAndVers.first;
     RISCVISAInfo::ExtensionVersion ExtVers = SeenExtAndVers.second;
 
-    if (!RISCVISAInfo::isSupportedExtension(ExtName)) {
-      if (ExtName.size() == 1) {
-        return createStringError(errc::invalid_argument,
-                                 "unsupported standard user-level extension '" +
-                                     ExtName + "'");
-      }
-      return createStringError(errc::invalid_argument,
-                               "unsupported " + getExtensionTypeDesc(ExtName) +
-                                   " '" + ExtName + "'");
-    }
+    if (!RISCVISAInfo::isSupportedExtension(ExtName))
+      return getStringErrorForInvalidExt(ExtName);
     ISAInfo->addExtension(ExtName, ExtVers);
   }
 

llvm/unittests/Support/RISCVISAInfoTest.cpp

@@ -218,6 +218,21 @@ TEST(ParseArchString, RejectsUnrecognizedExtensionNamesByDefault) {
       toString(
           RISCVISAInfo::parseArchString("rv64g_xmadeup", true).takeError()),
       "unsupported non-standard user-level extension 'xmadeup'");
+  EXPECT_EQ(
+      toString(RISCVISAInfo::parseArchString("rv64ib1p0", true).takeError()),
+      "unsupported standard user-level extension 'b'");
+  EXPECT_EQ(
+      toString(
+          RISCVISAInfo::parseArchString("rv32i_zmadeup1p0", true).takeError()),
+      "unsupported standard user-level extension 'zmadeup'");
+  EXPECT_EQ(
+      toString(
+          RISCVISAInfo::parseArchString("rv64g_smadeup1p0", true).takeError()),
+      "unsupported standard supervisor-level extension 'smadeup'");
+  EXPECT_EQ(
+      toString(
+          RISCVISAInfo::parseArchString("rv64g_xmadeup1p0", true).takeError()),
+      "unsupported non-standard user-level extension 'xmadeup'");
 }
 
 TEST(ParseArchString, IgnoresUnrecognizedExtensionNamesWithIgnoreUnknown) {