[NFC][TableGen] Emit more readable builtin string table (#105445)

- Add `EmitStringLiteralDef` to StringToOffsetTable class to emit more
readable string table.
- Use that in `EmitIntrinsicToBuiltinMap`.

Author: jurahul

llvm/include/llvm/TableGen/StringToOffsetTable.h

@@ -12,6 +12,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cctype>
 #include <optional>
@@ -52,6 +53,31 @@ class StringToOffsetTable {
     return II->second;
   }
 
+  // Emit the string using string literal concatenation, for better readability
+  // and searchability.
+  void EmitStringLiteralDef(raw_ostream &OS, const Twine &Decl,
+                            const Twine &Indent = "  ") const {
+    OS << formatv(R"(
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Woverlength-strings"
+#endif
+{0}{1} = )",
+                  Indent, Decl);
+
+    for (StringRef Str : split(AggregateString, '\0')) {
+      OS << "\n" << Indent << "  \"";
+      OS.write_escaped(Str);
+      OS << "\\0\"";
+    }
+    OS << R"(;
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+)";
+  }
+
+  // Emit the string as one single string.
   void EmitString(raw_ostream &O) {
     // Escape the string.
     SmallString<256> Str;

llvm/utils/TableGen/IntrinsicEmitter.cpp

@@ -669,9 +669,7 @@ Intrinsic::getIntrinsicFor{1}Builtin(StringRef TargetPrefix,
   }
 
   if (!Table.empty()) {
-    OS << "  static constexpr char BuiltinNames[] = {\n";
-    Table.EmitCharArray(OS);
-    OS << "  };\n\n";
+    Table.EmitStringLiteralDef(OS, "static constexpr char BuiltinNames[]");
 
     OS << R"(
   struct BuiltinEntry {