[llvm] [NFC][TableGen] Refactor IntrinsicEmitter code (PR #106479)

[Rahul Joshi via llvm-commits]

================
@@ -213,95 +218,94 @@ void IntrinsicEmitter::EmitIITInfo(raw_ostream &OS) {
 
 void IntrinsicEmitter::EmitTargetInfo(const CodeGenIntrinsicTable &Ints,
                                       raw_ostream &OS) {
-  OS << "// Target mapping.\n";
-  OS << "#ifdef GET_INTRINSIC_TARGET_DATA\n";
-  OS << "struct IntrinsicTargetInfo {\n"
-     << "  llvm::StringLiteral Name;\n"
-     << "  size_t Offset;\n"
-     << "  size_t Count;\n"
-     << "};\n";
-  OS << "static constexpr IntrinsicTargetInfo TargetInfos[] = {\n";
-  for (const auto &Target : Ints.Targets)
-    OS << "  {llvm::StringLiteral(\"" << Target.Name << "\"), " << Target.Offset
-       << ", " << Target.Count << "},\n";
-  OS << "};\n";
-  OS << "#endif\n\n";
+  OS << R"(// Target mapping.
+#ifdef GET_INTRINSIC_TARGET_DATA
+struct IntrinsicTargetInfo {
+  StringLiteral Name;
+  size_t Offset;
+  size_t Count;
+};
+static constexpr IntrinsicTargetInfo TargetInfos[] = {
+)";
+  for (const auto [Name, Offset, Count] : Ints.Targets)
+    OS << formatv("  {{\"{0}\", {1}, {2}},\n", Name, Offset, Count);
+  OS << R"(};
+#endif
+
+)";
 }
 
 void IntrinsicEmitter::EmitIntrinsicToNameTable(
     const CodeGenIntrinsicTable &Ints, raw_ostream &OS) {
-  OS << "// Intrinsic ID to name table.\n";
-  OS << "#ifdef GET_INTRINSIC_NAME_TABLE\n";
-  OS << "  // Note that entry #0 is the invalid intrinsic!\n";
+  OS << R"(// Intrinsic ID to name table.
+#ifdef GET_INTRINSIC_NAME_TABLE
+// Note that entry #0 is the invalid intrinsic!
+)";
   for (const auto &Int : Ints)
     OS << "  \"" << Int.Name << "\",\n";
   OS << "#endif\n\n";
 }
 
 void IntrinsicEmitter::EmitIntrinsicToOverloadTable(
     const CodeGenIntrinsicTable &Ints, raw_ostream &OS) {
-  OS << "// Intrinsic ID to overload bitset.\n";
-  OS << "#ifdef GET_INTRINSIC_OVERLOAD_TABLE\n";
-  OS << "static constexpr uint8_t OTable[] = {\n";
-  OS << "  0";
-  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
+  OS << R"(// Intrinsic ID to overload bitset.
+#ifdef GET_INTRINSIC_OVERLOAD_TABLE
+static constexpr uint8_t OTable[] = {
+  0
+  )";
+  for (auto [I, Int] : enumerate(Ints)) {
     // Add one to the index so we emit a null bit for the invalid #0 intrinsic.
-    if ((i + 1) % 8 == 0)
+    size_t Idx = I + 1;
+
+    if (Idx % 8 == 0)
       OS << ",\n  0";
-    if (Ints[i].isOverloaded)
-      OS << " | (1<<" << (i + 1) % 8 << ')';
+    if (Int.isOverloaded)
+      OS << " | (1<<" << Idx % 8 << ')';
   }
   OS << "\n};\n\n";
   // OTable contains a true bit at the position if the intrinsic is overloaded.
   OS << "return (OTable[id/8] & (1 << (id%8))) != 0;\n";
   OS << "#endif\n\n";
 }
 
-/// ComputeFixedEncoding - If we can encode the type signature for this
-/// intrinsic into 32 bits, return it.  If not, return ~0U.
-static void ComputeFixedEncoding(const CodeGenIntrinsic &Int,
-                                 std::vector<unsigned char> &TypeSig) {
-  if (auto *R = Int.TheDef->getValue("TypeSig")) {
-    for (auto &a : cast<ListInit>(R->getValue())->getValues()) {
-      for (auto &b : cast<ListInit>(a)->getValues())
+/// ComputeTypeSignature - Compute type signature of the intrinsic `Int`.
+static std::vector<unsigned char>
+ComputeTypeSignature(const CodeGenIntrinsic &Int) {
+  std::vector<unsigned char> TypeSig;
+  if (const auto *R = Int.TheDef->getValue("TypeSig")) {
+    for (const auto *a : cast<ListInit>(R->getValue())->getValues()) {
+      for (const auto *b : cast<ListInit>(a)->getValues())
         TypeSig.push_back(cast<IntInit>(b)->getValue());
     }
   }
-}
-
-static void printIITEntry(raw_ostream &OS, unsigned char X) {
-  OS << (unsigned)X;
+  return TypeSig;
 }
 
 void IntrinsicEmitter::EmitGenerator(const CodeGenIntrinsicTable &Ints,
                                      raw_ostream &OS) {
   // If we can compute a 32-bit fixed encoding for this intrinsic, do so and
   // capture it in this vector, otherwise store a ~0U.
   std::vector<unsigned> FixedEncodings;
-
   SequenceToOffsetTable<std::vector<unsigned char>> LongEncodingTable;
 
-  std::vector<unsigned char> TypeSig;
-
   // Compute the unique argument type info.
-  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
+  for (const CodeGenIntrinsic &Int : Ints) {
     // Get the signature for the intrinsic.
-    TypeSig.clear();
-    ComputeFixedEncoding(Ints[i], TypeSig);
+    std::vector<unsigned char> TypeSig = ComputeTypeSignature(Int);
----------------
jurahul wrote:

Done. I also added a `FixedEncodings.reserve()` to avoid its heap allocations.

https://github.com/llvm/llvm-project/pull/106479