Revert "[flang] add option to generate runtime type info as external" (#146064)

Reverts llvm/llvm-project#145901

Broke shared library builds because of the usage of
`skipExternalRttiDefinition` in Lowering.

Author: jeanPerier

flang/include/flang/Evaluate/tools.h

@@ -1585,7 +1585,6 @@ bool IsExtensibleType(const DerivedTypeSpec *);
 bool IsSequenceOrBindCType(const DerivedTypeSpec *);
 bool IsBuiltinDerivedType(const DerivedTypeSpec *derived, const char *name);
 bool IsBuiltinCPtr(const Symbol &);
-bool IsFromBuiltinModule(const Symbol &);
 bool IsEventType(const DerivedTypeSpec *);
 bool IsLockType(const DerivedTypeSpec *);
 bool IsNotifyType(const DerivedTypeSpec *);

flang/include/flang/Optimizer/CodeGen/CodeGen.h

@@ -39,9 +39,6 @@ struct FIRToLLVMPassOptions {
   // that such programs would crash at runtime if the derived type descriptors
   // are required by the runtime, so this is only an option to help debugging.
   bool ignoreMissingTypeDescriptors = false;
-  // Similar to ignoreMissingTypeDescriptors, but generate external declaration
-  // for the missing type descriptor globals instead.
-  bool skipExternalRttiDefinition = false;
 
   // Generate TBAA information for FIR types and memory accessing operations.
   bool applyTBAA = false;

flang/include/flang/Optimizer/Passes/CommandLineOpts.h

@@ -32,19 +32,6 @@ extern llvm::cl::opt<std::size_t> arrayStackAllocationThreshold;
 /// generated by the frontend.
 extern llvm::cl::opt<bool> ignoreMissingTypeDescriptors;
 
-/// Shared option in tools to only generate rtti static object definitions for
-/// derived types defined in the current compilation unit. Derived type
-/// descriptor object for types defined in other objects will only be declared
-/// as external. This also changes the linkage of rtti objects defined in the
-/// current compilation unit from linkonce_odr to external so that unused rtti
-/// objects are retained and can be accessed from other compilation units. This
-/// is an experimental option to explore compilation speed improvements and is
-/// an ABI breaking change because of the linkage change.
-/// It will also require linking against module file objects of modules defining
-/// only types (even for trivial types without type bound procedures, which
-/// differs from most compilers).
-extern llvm::cl::opt<bool> skipExternalRttiDefinition;
-
 /// Default optimization level used to create Flang pass pipeline is O0.
 extern llvm::OptimizationLevel defaultOptLevel;
 

flang/include/flang/Optimizer/Support/Utils.h

@@ -35,6 +35,32 @@ inline std::int64_t toInt(mlir::arith::ConstantOp cop) {
       .getSExtValue();
 }
 
+// Reconstruct binding tables for dynamic dispatch.
+using BindingTable = llvm::DenseMap<llvm::StringRef, unsigned>;
+using BindingTables = llvm::DenseMap<llvm::StringRef, BindingTable>;
+
+inline void buildBindingTables(BindingTables &bindingTables,
+                               mlir::ModuleOp mod) {
+
+  // The binding tables are defined in FIR after lowering inside fir.type_info
+  // operations. Go through each binding tables and store the procedure name and
+  // binding index for later use by the fir.dispatch conversion pattern.
+  for (auto typeInfo : mod.getOps<fir::TypeInfoOp>()) {
+    unsigned bindingIdx = 0;
+    BindingTable bindings;
+    if (typeInfo.getDispatchTable().empty()) {
+      bindingTables[typeInfo.getSymName()] = bindings;
+      continue;
+    }
+    for (auto dtEntry :
+         typeInfo.getDispatchTable().front().getOps<fir::DTEntryOp>()) {
+      bindings[dtEntry.getMethod()] = bindingIdx;
+      ++bindingIdx;
+    }
+    bindingTables[typeInfo.getSymName()] = bindings;
+  }
+}
+
 // Translate front-end KINDs for use in the IR and code gen.
 inline std::vector<fir::KindTy>
 fromDefaultKinds(const Fortran::common::IntrinsicTypeDefaultKinds &defKinds) {

flang/include/flang/Semantics/runtime-type-info.h

@@ -38,10 +38,6 @@ RuntimeDerivedTypeTables BuildRuntimeDerivedTypeTables(SemanticsContext &);
 /// to describe other derived types at runtime in flang descriptor.
 constexpr char typeInfoBuiltinModule[]{"__fortran_type_info"};
 
-/// Name of the builtin derived type in __fortran_type_inf that is used for
-/// derived type descriptors.
-constexpr char typeDescriptorTypeName[]{"derivedtype"};
-
 /// Name of the bindings descriptor component in the DerivedType type of the
 /// __Fortran_type_info module
 constexpr char bindingDescCompName[]{"binding"};

flang/lib/Evaluate/tools.cpp

@@ -2334,11 +2334,6 @@ bool IsBuiltinCPtr(const Symbol &symbol) {
   return false;
 }
 
-bool IsFromBuiltinModule(const Symbol &symbol) {
-  const Scope &scope{symbol.GetUltimate().owner()};
-  return IsSameModule(&scope, scope.context().GetBuiltinsScope());
-}
-
 bool IsIsoCType(const DerivedTypeSpec *derived) {
   return IsBuiltinDerivedType(derived, "c_ptr") ||
       IsBuiltinDerivedType(derived, "c_funptr");

flang/lib/Lower/Bridge.cpp

@@ -52,7 +52,6 @@
 #include "flang/Optimizer/Dialect/FIROps.h"
 #include "flang/Optimizer/Dialect/Support/FIRContext.h"
 #include "flang/Optimizer/HLFIR/HLFIROps.h"
-#include "flang/Optimizer/Passes/CommandLineOpts.h"
 #include "flang/Optimizer/Support/DataLayout.h"
 #include "flang/Optimizer/Support/FatalError.h"
 #include "flang/Optimizer/Support/InternalNames.h"
@@ -263,7 +262,6 @@ class TypeInfoConverter {
   }
 
   void createTypeInfo(Fortran::lower::AbstractConverter &converter) {
-    createTypeInfoForTypeDescriptorBuiltinType(converter);
     while (!registeredTypeInfoA.empty()) {
       currentTypeInfoStack = &registeredTypeInfoB;
       for (const TypeInfo &info : registeredTypeInfoA)
@@ -279,22 +277,10 @@ class TypeInfoConverter {
 private:
   void createTypeInfoOpAndGlobal(Fortran::lower::AbstractConverter &converter,
                                  const TypeInfo &info) {
-    if (!::skipExternalRttiDefinition)
-      Fortran::lower::createRuntimeTypeInfoGlobal(converter, info.symbol.get());
+    Fortran::lower::createRuntimeTypeInfoGlobal(converter, info.symbol.get());
     createTypeInfoOp(converter, info);
   }
 
-  void createTypeInfoForTypeDescriptorBuiltinType(
-      Fortran::lower::AbstractConverter &converter) {
-    if (registeredTypeInfoA.empty())
-      return;
-    auto builtinTypeInfoType = llvm::cast<fir::RecordType>(
-        converter.genType(registeredTypeInfoA[0].symbol.get()));
-    converter.getFirOpBuilder().createTypeInfoOp(
-        registeredTypeInfoA[0].loc, builtinTypeInfoType,
-        /*parentType=*/fir::RecordType{});
-  }
-
   void createTypeInfoOp(Fortran::lower::AbstractConverter &converter,
                         const TypeInfo &info) {
     fir::RecordType parentType{};

flang/lib/Lower/ConvertVariable.cpp

@@ -38,7 +38,6 @@
 #include "flang/Optimizer/Dialect/FIROps.h"
 #include "flang/Optimizer/Dialect/Support/FIRContext.h"
 #include "flang/Optimizer/HLFIR/HLFIROps.h"
-#include "flang/Optimizer/Passes/CommandLineOpts.h"
 #include "flang/Optimizer/Support/FatalError.h"
 #include "flang/Optimizer/Support/InternalNames.h"
 #include "flang/Optimizer/Support/Utils.h"
@@ -653,13 +652,8 @@ getLinkageAttribute(fir::FirOpBuilder &builder,
   // Runtime type info for a same derived type is identical in each compilation
   // unit. It desired to avoid having to link against module that only define a
   // type. Therefore the runtime type info is generated everywhere it is needed
-  // with `linkonce_odr` LLVM linkage (unless the skipExternalRttiDefinition
-  // option is set, in which case one will need to link against objects of
-  // modules defining types). Builtin objects rtti is always generated because
-  // the builtin module is currently not compiled or part of the runtime.
-  if (var.isRuntimeTypeInfoData() &&
-      (!::skipExternalRttiDefinition ||
-       Fortran::semantics::IsFromBuiltinModule(var.getSymbol())))
+  // with `linkonce_odr` LLVM linkage.
+  if (var.isRuntimeTypeInfoData())
     return builder.createLinkOnceODRLinkage();
   if (var.isModuleOrSubmoduleVariable())
     return {}; // external linkage

flang/lib/Optimizer/CodeGen/CodeGen.cpp

@@ -1294,51 +1294,6 @@ genCUFAllocDescriptor(mlir::Location loc,
       .getResult();
 }
 
-/// Get the address of the type descriptor global variable that was created by
-/// lowering for derived type \p recType.
-template <typename ModOpTy>
-static mlir::Value
-getTypeDescriptor(ModOpTy mod, mlir::ConversionPatternRewriter &rewriter,
-                  mlir::Location loc, fir::RecordType recType,
-                  const fir::FIRToLLVMPassOptions &options) {
-  std::string name =
-      options.typeDescriptorsRenamedForAssembly
-          ? fir::NameUniquer::getTypeDescriptorAssemblyName(recType.getName())
-          : fir::NameUniquer::getTypeDescriptorName(recType.getName());
-  mlir::Type llvmPtrTy = ::getLlvmPtrType(mod.getContext());
-  if (auto global = mod.template lookupSymbol<fir::GlobalOp>(name))
-    return rewriter.create<mlir::LLVM::AddressOfOp>(loc, llvmPtrTy,
-                                                    global.getSymName());
-  // The global may have already been translated to LLVM.
-  if (auto global = mod.template lookupSymbol<mlir::LLVM::GlobalOp>(name))
-    return rewriter.create<mlir::LLVM::AddressOfOp>(loc, llvmPtrTy,
-                                                    global.getSymName());
-  // Type info derived types do not have type descriptors since they are the
-  // types defining type descriptors.
-  if (options.ignoreMissingTypeDescriptors ||
-      fir::NameUniquer::belongsToModule(
-          name, Fortran::semantics::typeInfoBuiltinModule))
-    return rewriter.create<mlir::LLVM::ZeroOp>(loc, llvmPtrTy);
-
-  if (!options.skipExternalRttiDefinition)
-    fir::emitFatalError(loc,
-                        "runtime derived type info descriptor was not "
-                        "generated and skipExternalRttiDefinition and "
-                        "ignoreMissingTypeDescriptors options are not set");
-
-  // Rtti for a derived type defined in another compilation unit and for which
-  // rtti was not defined in lowering because of the skipExternalRttiDefinition
-  // option. Generate the object declaration now.
-  auto insertPt = rewriter.saveInsertionPoint();
-  rewriter.setInsertionPoint(mod.getBody(), mod.getBody()->end());
-  mlir::LLVM::GlobalOp global = rewriter.create<mlir::LLVM::GlobalOp>(
-      loc, llvmPtrTy, /*constant=*/true, mlir::LLVM::Linkage::External, name,
-      mlir::Attribute());
-  rewriter.restoreInsertionPoint(insertPt);
-  return rewriter.create<mlir::LLVM::AddressOfOp>(loc, llvmPtrTy,
-                                                  global.getSymName());
-}
-
 /// Common base class for embox to descriptor conversion.
 template <typename OP>
 struct EmboxCommonConversion : public fir::FIROpConversion<OP> {
@@ -1451,6 +1406,36 @@ struct EmboxCommonConversion : public fir::FIROpConversion<OP> {
                        stride);
   }
 
+  /// Get the address of the type descriptor global variable that was created by
+  /// lowering for derived type \p recType.
+  template <typename ModOpTy>
+  mlir::Value
+  getTypeDescriptor(ModOpTy mod, mlir::ConversionPatternRewriter &rewriter,
+                    mlir::Location loc, fir::RecordType recType) const {
+    std::string name =
+        this->options.typeDescriptorsRenamedForAssembly
+            ? fir::NameUniquer::getTypeDescriptorAssemblyName(recType.getName())
+            : fir::NameUniquer::getTypeDescriptorName(recType.getName());
+    mlir::Type llvmPtrTy = ::getLlvmPtrType(mod.getContext());
+    if (auto global = mod.template lookupSymbol<fir::GlobalOp>(name)) {
+      return rewriter.create<mlir::LLVM::AddressOfOp>(loc, llvmPtrTy,
+                                                      global.getSymName());
+    }
+    if (auto global = mod.template lookupSymbol<mlir::LLVM::GlobalOp>(name)) {
+      // The global may have already been translated to LLVM.
+      return rewriter.create<mlir::LLVM::AddressOfOp>(loc, llvmPtrTy,
+                                                      global.getSymName());
+    }
+    // Type info derived types do not have type descriptors since they are the
+    // types defining type descriptors.
+    if (!this->options.ignoreMissingTypeDescriptors &&
+        !fir::NameUniquer::belongsToModule(
+            name, Fortran::semantics::typeInfoBuiltinModule))
+      fir::emitFatalError(
+          loc, "runtime derived type info descriptor was not generated");
+    return rewriter.create<mlir::LLVM::ZeroOp>(loc, llvmPtrTy);
+  }
+
   template <typename ModOpTy>
   mlir::Value populateDescriptor(mlir::Location loc, ModOpTy mod,
                                  fir::BaseBoxType boxTy, mlir::Type inputType,
@@ -1515,17 +1500,16 @@ struct EmboxCommonConversion : public fir::FIROpConversion<OP> {
           mlir::Type innerType = fir::unwrapInnerType(inputType);
           if (innerType && mlir::isa<fir::RecordType>(innerType)) {
             auto recTy = mlir::dyn_cast<fir::RecordType>(innerType);
-            typeDesc =
-                getTypeDescriptor(mod, rewriter, loc, recTy, this->options);
+            typeDesc = getTypeDescriptor(mod, rewriter, loc, recTy);
           } else {
             // Unlimited polymorphic type descriptor with no record type. Set
             // type descriptor address to a clean state.
             typeDesc = rewriter.create<mlir::LLVM::ZeroOp>(
                 loc, ::getLlvmPtrType(mod.getContext()));
           }
         } else {
-          typeDesc = getTypeDescriptor(
-              mod, rewriter, loc, fir::unwrapIfDerived(boxTy), this->options);
+          typeDesc = getTypeDescriptor(mod, rewriter, loc,
+                                       fir::unwrapIfDerived(boxTy));
         }
       }
       if (typeDesc)
@@ -3037,10 +3021,22 @@ struct TypeDescOpConversion : public fir::FIROpConversion<fir::TypeDescOp> {
     assert(mlir::isa<fir::RecordType>(inTy) && "expecting fir.type");
     auto recordType = mlir::dyn_cast<fir::RecordType>(inTy);
     auto module = typeDescOp.getOperation()->getParentOfType<mlir::ModuleOp>();
-    mlir::Value typeDesc = getTypeDescriptor(
-        module, rewriter, typeDescOp.getLoc(), recordType, this->options);
-    rewriter.replaceOp(typeDescOp, typeDesc);
-    return mlir::success();
+    std::string typeDescName =
+        this->options.typeDescriptorsRenamedForAssembly
+            ? fir::NameUniquer::getTypeDescriptorAssemblyName(
+                  recordType.getName())
+            : fir::NameUniquer::getTypeDescriptorName(recordType.getName());
+    auto llvmPtrTy = ::getLlvmPtrType(typeDescOp.getContext());
+    if (auto global = module.lookupSymbol<mlir::LLVM::GlobalOp>(typeDescName)) {
+      rewriter.replaceOpWithNewOp<mlir::LLVM::AddressOfOp>(
+          typeDescOp, llvmPtrTy, global.getSymName());
+      return mlir::success();
+    } else if (auto global = module.lookupSymbol<fir::GlobalOp>(typeDescName)) {
+      rewriter.replaceOpWithNewOp<mlir::LLVM::AddressOfOp>(
+          typeDescOp, llvmPtrTy, global.getSymName());
+      return mlir::success();
+    }
+    return mlir::failure();
   }
 };
 

flang/lib/Optimizer/Passes/CommandLineOpts.cpp

@@ -39,12 +39,6 @@ cl::opt<bool> ignoreMissingTypeDescriptors(
              "translating FIR to LLVM"),
     cl::init(false), cl::Hidden);
 
-cl::opt<bool> skipExternalRttiDefinition(
-    "skip-external-rtti-definition", llvm::cl::init(false),
-    llvm::cl::desc("do not define rtti static objects for types belonging to "
-                   "other compilation units"),
-    cl::Hidden);
-
 OptimizationLevel defaultOptLevel{OptimizationLevel::O0};
 
 codegenoptions::DebugInfoKind noDebugInfo{codegenoptions::NoDebugInfo};