[llvm] TableGen: Allow defining sets of runtime libraries (PR #144978)

[Daniel Paoliello via llvm-commits]

================
@@ -297,48 +295,190 @@ void RuntimeLibcallEmitter::emitGetInitRuntimeLibcallNames(
     OS << '\n';
   }
   OS << "};\n\n";
+}
 
-  std::vector<RuntimeLibcallImpl> ZOSRuntimeLibcallImplList =
-      getRuntimeLibcallImplSet("ZOSRuntimeLibcallImpl");
-  emitTargetOverrideFunc(OS, "setZOSLibCallNameOverrides",
-                         ZOSRuntimeLibcallImplList);
+void RuntimeLibcallEmitter::emitSystemRuntimeLibrarySetCalls(
+    raw_ostream &OS) const {
+  OS << "void llvm::RTLIB::RuntimeLibcallsInfo::setTargetRuntimeLibcallSets("
+        "const llvm::Triple &TT) {\n"
+        "  struct LibcallImplPair {\n"
+        "    RTLIB::Libcall Func;\n"
+        "    RTLIB::LibcallImpl Impl;\n"
+        "  };\n";
+  ArrayRef<const Record *> AllLibs =
+      Records.getAllDerivedDefinitions("SystemRuntimeLibrary");
+
+  for (const Record *R : AllLibs) {
+    OS << '\n';
 
-  std::vector<RuntimeLibcallImpl> PPCRuntimeLibcallImplList =
-      getRuntimeLibcallImplSet("PPCRuntimeLibcallImpl");
-  emitTargetOverrideFunc(OS, "setPPCLibCallNameOverrides",
-                         PPCRuntimeLibcallImplList);
+    AvailabilityPredicate TopLevelPredicate(R->getValueAsDef("TriplePred"));
 
-  emitWindowsArm64LibCallNameOverrides(OS);
-}
+    OS << indent(2);
+    TopLevelPredicate.emitIf(OS);
+    SetTheory Sets;
 
-void RuntimeLibcallEmitter::emitGetInitRuntimeLibcallUtils(
-    raw_ostream &OS) const {
-  // FIXME: Hack we shouldn't really need
-  OS << "#ifdef GET_INIT_RUNTIME_LIBCALL_UTILS\n"
-        "static inline bool isAtomicLibCall(llvm::RTLIB::Libcall LC) {\n"
-        "  switch (LC) {\n";
-  for (const RuntimeLibcall &LibCall : RuntimeLibcallDefList) {
-    StringRef Name = LibCall.getName();
-    if (Name.contains("ATOMIC")) {
-      OS << "  case ";
-      LibCall.emitEnumEntry(OS);
-      OS << ":\n";
+    DenseMap<const Record *, std::vector<const Record *>> Func2Preds;
+    Sets.addExpander(
+        "LibcallImpls",
+        std::make_unique<LibcallPredicateExpander>(*this, Func2Preds));
+
+    const SetTheory::RecVec *Elements =
+        Sets.expand(R->getValueAsDef("MemberList"));
+
+    // Sort to get deterministic output
+    SetVector<const Record *> PredicateSorter;
+    PredicateSorter.insert(nullptr); // No predicate first.
+
+    DenseMap<const Record *, std::vector<const RuntimeLibcallImpl *>>
+        Pred2Funcs;
+    for (const Record *Elt : *Elements) {
+      const RuntimeLibcallImpl *LibCallImpl = getRuntimeLibcallImpl(Elt);
+      if (!LibCallImpl) {
+        PrintError(R, "entry for SystemLibrary is not a RuntimeLibcallImpl");
+
+        PrintNote(Elt->getLoc(), "invalid entry `" + Elt->getName() + "`");
+
+        continue;
+      }
+
+      auto It = Func2Preds.find(Elt);
+      if (It == Func2Preds.end()) {
+        Pred2Funcs[nullptr].push_back(LibCallImpl);
+        continue;
+      }
+
+      for (const Record *Pred : It->second) {
+        Pred2Funcs[Pred].push_back(LibCallImpl);
+        PredicateSorter.insert(Pred);
+      }
+    }
+
+    SmallVector<const Record *, 0> SortedPredicates =
+        PredicateSorter.takeVector();
+
+    sort(SortedPredicates, [](const Record *A, const Record *B) {
+      if (!A)
+        return true;
+      if (!B)
+        return false;
+      return A->getName() < B->getName();
+    });
+
+    for (const Record *Pred : SortedPredicates) {
+      AvailabilityPredicate SubsetPredicate(Pred);
+      unsigned IndentDepth = 2;
+
+      auto It = Pred2Funcs.find(Pred);
+      if (It == Pred2Funcs.end())
+        continue;
+
+      if (!SubsetPredicate.isAlwaysAvailable()) {
+        IndentDepth = 4;
+
+        OS << indent(IndentDepth);
+        SubsetPredicate.emitIf(OS);
+      }
+
+      std::vector<const RuntimeLibcallImpl *> &Funcs = It->second;
+
+      // Ensure we only emit a unique implementation per libcall in the
+      // selection table.
+      //
+      // FIXME: We need to generate separate functions for
----------------
dpaoliello wrote:

Addressed in later PR?

https://github.com/llvm/llvm-project/pull/144978