Update MLIR conversion to LLVMFunc to account better for properties (#67406)

joker-eph · web-flow · commit cb550c178d4a · 2023-10-09T00:41:03.000-07:00
Change the attribute propagation to handle only discardable attributes,
inherent attribute are handled directly and args/results through the
interface.
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
@@ -1395,6 +1395,7 @@ def LLVM_LLVMFuncOp : LLVM_Op<"func", [
 
   let arguments = (ins
     StrAttr:$sym_name,
+    OptionalAttr<StrAttr>:$sym_visibility,
     TypeAttrOf<LLVM_FunctionType>:$function_type,
     DefaultValuedAttr<Linkage, "Linkage::External">:$linkage,
     UnitAttr:$dso_local,
diff --git a/mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp b/mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp
@@ -73,44 +73,40 @@ static bool shouldUseBarePtrCallConv(Operation *op,
 }
 
 /// Only retain those attributes that are not constructed by
-/// `LLVMFuncOp::build`. If `filterArgAttrs` is set, also filter out argument
-/// attributes.
-static void filterFuncAttributes(func::FuncOp func, bool filterArgAndResAttrs,
+/// `LLVMFuncOp::build`.
+static void filterFuncAttributes(func::FuncOp func,
                                  SmallVectorImpl<NamedAttribute> &result) {
-  for (const NamedAttribute &attr : func->getAttrs()) {
-    if (attr.getName() == SymbolTable::getSymbolAttrName() ||
-        attr.getName() == func.getFunctionTypeAttrName() ||
-        attr.getName() == linkageAttrName ||
+  for (const NamedAttribute &attr : func->getDiscardableAttrs()) {
+    if (attr.getName() == linkageAttrName ||
         attr.getName() == varargsAttrName ||
-        attr.getName() == LLVM::LLVMDialect::getReadnoneAttrName() ||
-        (filterArgAndResAttrs &&
-         (attr.getName() == func.getArgAttrsAttrName() ||
-          attr.getName() == func.getResAttrsAttrName())))
+        attr.getName() == LLVM::LLVMDialect::getReadnoneAttrName())
       continue;
     result.push_back(attr);
   }
 }
 
-/// Adds a an empty set of argument attributes for the newly added argument in
-/// front of the existing ones.
-static void prependEmptyArgAttr(OpBuilder &builder,
-                                SmallVectorImpl<NamedAttribute> &newFuncAttrs,
-                                func::FuncOp func) {
-  auto argAttrs = func.getArgAttrs();
-  // Nothing to do when there were no arg attrs beforehand.
-  if (!argAttrs)
-    return;
-
-  size_t numArguments = func.getNumArguments();
-  SmallVector<Attribute> newArgAttrs;
-  newArgAttrs.reserve(numArguments + 1);
-  // Insert empty dictionary for the new argument.
-  newArgAttrs.push_back(builder.getDictionaryAttr({}));
-
-  llvm::append_range(newArgAttrs, *argAttrs);
-  auto newNamedAttr = builder.getNamedAttr(func.getArgAttrsAttrName(),
-                                           builder.getArrayAttr(newArgAttrs));
-  newFuncAttrs.push_back(newNamedAttr);
+/// Propagate argument/results attributes.
+static void propagateArgResAttrs(OpBuilder &builder, bool resultStructType,
+                                 func::FuncOp funcOp,
+                                 LLVM::LLVMFuncOp wrapperFuncOp) {
+  auto argAttrs = funcOp.getArgAttrs();
+  if (!resultStructType) {
+    if (auto resAttrs = funcOp.getAllResultAttrs())
+      wrapperFuncOp.setAllResultAttrs(resAttrs);
+    if (argAttrs)
+      wrapperFuncOp.setAllArgAttrs(*argAttrs);
+  } else {
+    SmallVector<Attribute> argAttributes;
+    // Only modify the argument and result attributes when the result is now
+    // an argument.
+    if (argAttrs) {
+      argAttributes.push_back(builder.getDictionaryAttr({}));
+      argAttributes.append(argAttrs->begin(), argAttrs->end());
+      wrapperFuncOp.setAllArgAttrs(argAttributes);
+    }
+  }
+  if (funcOp.getSymVisibilityAttr())
+    wrapperFuncOp.setSymVisibility(funcOp.getSymVisibilityAttr());
 }
 
 /// Creates an auxiliary function with pointer-to-memref-descriptor-struct
@@ -129,18 +125,14 @@ static void wrapForExternalCallers(OpBuilder &rewriter, Location loc,
   auto [wrapperFuncType, resultStructType] =
       typeConverter.convertFunctionTypeCWrapper(type);
 
-  SmallVector<NamedAttribute, 4> attributes;
-  // Only modify the argument and result attributes when the result is now an
-  // argument.
-  if (resultStructType)
-    prependEmptyArgAttr(rewriter, attributes, funcOp);
-  filterFuncAttributes(
-      funcOp, /*filterArgAndResAttrs=*/static_cast<bool>(resultStructType),
-      attributes);
+  SmallVector<NamedAttribute> attributes;
+  filterFuncAttributes(funcOp, attributes);
+
   auto wrapperFuncOp = rewriter.create<LLVM::LLVMFuncOp>(
       loc, llvm::formatv("_mlir_ciface_{0}", funcOp.getName()).str(),
       wrapperFuncType, LLVM::Linkage::External, /*dsoLocal=*/false,
       /*cconv=*/LLVM::CConv::C, /*comdat=*/nullptr, attributes);
+  propagateArgResAttrs(rewriter, !!resultStructType, funcOp, wrapperFuncOp);
 
   OpBuilder::InsertionGuard guard(rewriter);
   rewriter.setInsertionPointToStart(wrapperFuncOp.addEntryBlock());
@@ -199,19 +191,14 @@ static void wrapExternalFunction(OpBuilder &builder, Location loc,
   assert(wrapperType && "unexpected type conversion failure");
 
   SmallVector<NamedAttribute, 4> attributes;
-  // Only modify the argument and result attributes when the result is now an
-  // argument.
-  if (resultStructType)
-    prependEmptyArgAttr(builder, attributes, funcOp);
-  filterFuncAttributes(
-      funcOp, /*filterArgAndResAttrs=*/static_cast<bool>(resultStructType),
-      attributes);
+  filterFuncAttributes(funcOp, attributes);
 
   // Create the auxiliary function.
   auto wrapperFunc = builder.create<LLVM::LLVMFuncOp>(
       loc, llvm::formatv("_mlir_ciface_{0}", funcOp.getName()).str(),
       wrapperType, LLVM::Linkage::External, /*dsoLocal=*/false,
       /*cconv=*/LLVM::CConv::C, /*comdat=*/nullptr, attributes);
+  propagateArgResAttrs(builder, !!resultStructType, funcOp, wrapperFunc);
 
   // The wrapper that we synthetize here should only be visible in this module.
   newFuncOp.setLinkage(LLVM::Linkage::Private);
@@ -351,21 +338,56 @@ struct FuncOpConversionBase : public ConvertOpToLLVMPattern<func::FuncOp> {
     if (!llvmType)
       return rewriter.notifyMatchFailure(funcOp, "signature conversion failed");
 
+    // Create an LLVM function, use external linkage by default until MLIR
+    // functions have linkage.
+    LLVM::Linkage linkage = LLVM::Linkage::External;
+    if (funcOp->hasAttr(linkageAttrName)) {
+      auto attr =
+          dyn_cast<mlir::LLVM::LinkageAttr>(funcOp->getAttr(linkageAttrName));
+      if (!attr) {
+        funcOp->emitError() << "Contains " << linkageAttrName
+                            << " attribute not of type LLVM::LinkageAttr";
+        return rewriter.notifyMatchFailure(
+            funcOp, "Contains linkage attribute not of type LLVM::LinkageAttr");
+      }
+      linkage = attr.getLinkage();
+    }
+
+    SmallVector<NamedAttribute, 4> attributes;
+    filterFuncAttributes(funcOp, attributes);
+    auto newFuncOp = rewriter.create<LLVM::LLVMFuncOp>(
+        funcOp.getLoc(), funcOp.getName(), llvmType, linkage,
+        /*dsoLocal=*/false, /*cconv=*/LLVM::CConv::C, /*comdat=*/nullptr,
+        attributes);
+    if (funcOp.getSymVisibilityAttr())
+      newFuncOp.setSymVisibility(funcOp.getSymVisibilityAttr());
+
+    // Create a memory effect attribute corresponding to readnone.
+    StringRef readnoneAttrName = LLVM::LLVMDialect::getReadnoneAttrName();
+    if (funcOp->hasAttr(readnoneAttrName)) {
+      auto attr = funcOp->getAttrOfType<UnitAttr>(readnoneAttrName);
+      if (!attr) {
+        funcOp->emitError() << "Contains " << readnoneAttrName
+                            << " attribute not of type UnitAttr";
+        return rewriter.notifyMatchFailure(
+            funcOp, "Contains readnone attribute not of type UnitAttr");
+      }
+      auto memoryAttr = LLVM::MemoryEffectsAttr::get(
+          rewriter.getContext(),
+          {LLVM::ModRefInfo::NoModRef, LLVM::ModRefInfo::NoModRef,
+           LLVM::ModRefInfo::NoModRef});
+      newFuncOp.setMemoryAttr(memoryAttr);
+    }
+
     // Propagate argument/result attributes to all converted arguments/result
     // obtained after converting a given original argument/result.
-    SmallVector<NamedAttribute, 4> attributes;
-    filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/true, attributes);
     if (ArrayAttr resAttrDicts = funcOp.getAllResultAttrs()) {
       assert(!resAttrDicts.empty() && "expected array to be non-empty");
-      auto newResAttrDicts =
-          (funcOp.getNumResults() == 1)
-              ? resAttrDicts
-              : rewriter.getArrayAttr(rewriter.getDictionaryAttr({}));
-      attributes.push_back(
-          rewriter.getNamedAttr(funcOp.getResAttrsAttrName(), newResAttrDicts));
+      if (funcOp.getNumResults() == 1)
+        newFuncOp.setAllResultAttrs(resAttrDicts);
     }
     if (ArrayAttr argAttrDicts = funcOp.getAllArgAttrs()) {
-      SmallVector<Attribute, 4> newArgAttrs(
+      SmallVector<Attribute> newArgAttrs(
           cast<LLVM::LLVMFunctionType>(llvmType).getNumParams());
       for (unsigned i = 0, e = funcOp.getNumArguments(); i < e; ++i) {
         // Some LLVM IR attribute have a type attached to them. During FuncOp ->
@@ -415,48 +437,10 @@ struct FuncOpConversionBase : public ConvertOpToLLVMPattern<func::FuncOp> {
           newArgAttrs[mapping->inputNo + j] =
               DictionaryAttr::get(rewriter.getContext(), {});
       }
-      attributes.push_back(rewriter.getNamedAttr(
-          funcOp.getArgAttrsAttrName(), rewriter.getArrayAttr(newArgAttrs)));
+      if (!newArgAttrs.empty())
+        newFuncOp.setAllArgAttrs(rewriter.getArrayAttr(newArgAttrs));
     }
 
-    // Create an LLVM function, use external linkage by default until MLIR
-    // functions have linkage.
-    LLVM::Linkage linkage = LLVM::Linkage::External;
-    if (funcOp->hasAttr(linkageAttrName)) {
-      auto attr =
-          dyn_cast<mlir::LLVM::LinkageAttr>(funcOp->getAttr(linkageAttrName));
-      if (!attr) {
-        funcOp->emitError() << "Contains " << linkageAttrName
-                            << " attribute not of type LLVM::LinkageAttr";
-        return rewriter.notifyMatchFailure(
-            funcOp, "Contains linkage attribute not of type LLVM::LinkageAttr");
-      }
-      linkage = attr.getLinkage();
-    }
-
-    // Create a memory effect attribute corresponding to readnone.
-    StringRef readnoneAttrName = LLVM::LLVMDialect::getReadnoneAttrName();
-    LLVM::MemoryEffectsAttr memoryAttr = {};
-    if (funcOp->hasAttr(readnoneAttrName)) {
-      auto attr = funcOp->getAttrOfType<UnitAttr>(readnoneAttrName);
-      if (!attr) {
-        funcOp->emitError() << "Contains " << readnoneAttrName
-                            << " attribute not of type UnitAttr";
-        return rewriter.notifyMatchFailure(
-            funcOp, "Contains readnone attribute not of type UnitAttr");
-      }
-      memoryAttr = LLVM::MemoryEffectsAttr::get(rewriter.getContext(),
-                                                {LLVM::ModRefInfo::NoModRef,
-                                                 LLVM::ModRefInfo::NoModRef,
-                                                 LLVM::ModRefInfo::NoModRef});
-    }
-    auto newFuncOp = rewriter.create<LLVM::LLVMFuncOp>(
-        funcOp.getLoc(), funcOp.getName(), llvmType, linkage,
-        /*dsoLocal=*/false, /*cconv=*/LLVM::CConv::C, /*comdat=*/nullptr,
-        attributes);
-    // If the memory attribute was created, add it to the function.
-    if (memoryAttr)
-      newFuncOp.setMemoryAttr(memoryAttr);
     rewriter.inlineRegionBefore(funcOp.getBody(), newFuncOp.getBody(),
                                 newFuncOp.end());
     if (failed(rewriter.convertRegionTypes(&newFuncOp.getBody(), *typeConverter,
diff --git a/mlir/test/Conversion/FuncToLLVM/convert-funcs.mlir b/mlir/test/Conversion/FuncToLLVM/convert-funcs.mlir
@@ -63,6 +63,21 @@ func.func @variadic_func(%arg0: i32) attributes { "func.varargs" = true } {
 
 // -----
 
+// CHECK-LABEL: llvm.func @private_callee
+// CHECK-SAME: sym_visibility = "private"
+func.func private @private_callee(%arg1: f32) -> i32 {
+  %0 = arith.constant 0 : i32
+  return %0 : i32
+}
+
+// CHECK-LABEL: llvm.func @caller_private_callee
+func.func @caller_private_callee(%arg1: f32) -> i32 {
+  %0 = call @private_callee(%arg1) : (f32) -> i32
+  return %0 : i32
+}
+
+// -----
+
 func.func private @badllvmlinkage(i32) attributes { "llvm.linkage" = 3 : i64 } // expected-error {{Contains llvm.linkage attribute not of type LLVM::LinkageAttr}}
 
 // -----
