[ThroughMLIR] basic printf support

clang/lib/CIR/Lowering/ThroughMLIR/LowerCIRToMLIR.cpp

@@ -23,10 +23,12 @@
 #include "mlir/Dialect/ControlFlow/IR/ControlFlowOps.h"
 #include "mlir/Dialect/Func/IR/FuncOps.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/Dialect/LLVMIR/LLVMTypes.h"
 #include "mlir/Dialect/Math/IR/Math.h"
 #include "mlir/Dialect/MemRef/IR/MemRef.h"
 #include "mlir/Dialect/SCF/IR/SCF.h"
 #include "mlir/Dialect/Vector/IR/VectorOps.h"
+#include "mlir/IR/BuiltinAttributes.h"
 #include "mlir/IR/BuiltinDialect.h"
 #include "mlir/IR/BuiltinOps.h"
 #include "mlir/IR/BuiltinTypes.h"
@@ -104,9 +106,124 @@ class CIRCallOpLowering : public mlir::OpConversionPattern<cir::CallOp> {
     if (mlir::failed(
             getTypeConverter()->convertTypes(op.getResultTypes(), types)))
       return mlir::failure();
-    rewriter.replaceOpWithNewOp<mlir::func::CallOp>(
-        op, op.getCalleeAttr(), types, adaptor.getOperands());
-    return mlir::LogicalResult::success();
+
+    if (!op.isIndirect()) {
+      // Currently variadic functions are not supported by the builtin func
+      // dialect. For now only basic call to printf are supported by using the
+      // llvmir dialect.
+      // TODO: remove this and add support for variadic function calls once
+      // TODO: supported by the func dialect
+      if (op.getCallee()->equals_insensitive("printf")) {
+        SmallVector<mlir::Type> operandTypes =
+            llvm::to_vector(adaptor.getOperands().getTypes());
+
+        // Drop the initial memref operand type (we replace the memref format
+        // string with equivalent llvm.mlir ops)
+        operandTypes.erase(operandTypes.begin());
+
+        // Check that the printf attributes can be used in llvmir dialect (i.e
+        // they have integer/float type)
+        if (!llvm::all_of(operandTypes, [](mlir::Type ty) {
+              return mlir::LLVM::isCompatibleType(ty);
+            })) {
+          return op.emitError()
+                 << "lowering of printf attributes having a type that is "
+                    "converted to memref in cir-to-mlir lowering (e.g. "
+                    "pointers) not supported yet";
+        }
+
+        // Currently only versions of printf are supported where the format
+        // string is defined inside the printf ==> the lowering of the cir ops
+        // will match:
+        // %global = memref.get_global %frm_str
+        // %* = memref.reinterpret_cast (%global, 0)
+        if (auto reinterpret_castOP =
+                mlir::dyn_cast_or_null<mlir::memref::ReinterpretCastOp>(
+                    adaptor.getOperands()[0].getDefiningOp())) {
+          if (auto getGlobalOp =
+                  mlir::dyn_cast_or_null<mlir::memref::GetGlobalOp>(
+                      reinterpret_castOP->getOperand(0).getDefiningOp())) {
+            mlir::ModuleOp parentModule = op->getParentOfType<mlir::ModuleOp>();
+
+            auto context = rewriter.getContext();
+
+            // Find the memref.global op defining the frm_str
+            auto globalOp = parentModule.lookupSymbol<mlir::memref::GlobalOp>(
+                getGlobalOp.getNameAttr());
+
+            rewriter.setInsertionPoint(globalOp);
+
+            // Insert a equivalent llvm.mlir.global
+            auto initialvalueAttr =
+                mlir::dyn_cast_or_null<mlir::DenseIntElementsAttr>(
+                    globalOp.getInitialValueAttr());
+
+            auto type = mlir::LLVM::LLVMArrayType::get(
+                mlir::IntegerType::get(context, 8),
+                initialvalueAttr.getNumElements());
+
+            auto llvmglobalOp = rewriter.create<mlir::LLVM::GlobalOp>(
+                globalOp->getLoc(), type, true, mlir::LLVM::Linkage::Internal,
+                "printf_format_" + globalOp.getSymName().str(),
+                initialvalueAttr, 0);
+
+            rewriter.setInsertionPoint(getGlobalOp);
+
+            // Insert llvmir dialect ops to retrive the !llvm.ptr of the global
+            auto globalPtrOp = rewriter.create<mlir::LLVM::AddressOfOp>(
+                getGlobalOp->getLoc(), llvmglobalOp);
+
+            mlir::Value cst0 = rewriter.create<mlir::LLVM::ConstantOp>(
+                getGlobalOp->getLoc(), rewriter.getI8Type(),
+                rewriter.getIndexAttr(0));
+            auto gepPtrOp = rewriter.create<mlir::LLVM::GEPOp>(
+                getGlobalOp->getLoc(),
+                mlir::LLVM::LLVMPointerType::get(context),
+                llvmglobalOp.getType(), globalPtrOp,
+                ArrayRef<mlir::Value>({cst0, cst0}));
+
+            mlir::ValueRange operands = adaptor.getOperands();
+
+            // Replace the old memref operand with the !llvm.ptr for the frm_str
+            mlir::SmallVector<mlir::Value> newOperands;
+            newOperands.push_back(gepPtrOp);
+            newOperands.append(operands.begin() + 1, operands.end());
+
+            // Create the llvmir dialect function type for printf
+            auto llvmI32Ty = mlir::IntegerType::get(context, 32);
+            auto llvmPtrTy = mlir::LLVM::LLVMPointerType::get(context);
+            auto llvmFnType =
+                mlir::LLVM::LLVMFunctionType::get(llvmI32Ty, llvmPtrTy,
+                                                  /*isVarArg=*/true);
+
+            rewriter.setInsertionPoint(op);
+
+            // Insert an llvm.call op with the updated operands to printf
+            rewriter.replaceOpWithNewOp<mlir::LLVM::CallOp>(
+                op, llvmFnType, op.getCalleeAttr(), newOperands);
+
+            // Cleanup printf frm_str memref ops
+            rewriter.eraseOp(reinterpret_castOP);
+            rewriter.eraseOp(getGlobalOp);
+            rewriter.eraseOp(globalOp);
+
+            return mlir::LogicalResult::success();
+          }
+        }
+
+        return op.emitError()
+               << "lowering of printf function with Format-String"
+                  "defined outside of printf is not supported yet";
+      }
+
+      rewriter.replaceOpWithNewOp<mlir::func::CallOp>(
+          op, op.getCalleeAttr(), types, adaptor.getOperands());
+      return mlir::LogicalResult::success();
+
+    } else {
+      // TODO: support lowering of indirect calls via func.call_indirect op
+      return op.emitError() << "lowering of indirect calls not supported yet";
+    }
   }
 };
 
@@ -557,37 +674,60 @@ class CIRFuncOpLowering : public mlir::OpConversionPattern<cir::FuncOp> {
                   mlir::ConversionPatternRewriter &rewriter) const override {
 
     auto fnType = op.getFunctionType();
-    mlir::TypeConverter::SignatureConversion signatureConversion(
-        fnType.getNumInputs());
 
-    for (const auto &argType : enumerate(fnType.getInputs())) {
-      auto convertedType = typeConverter->convertType(argType.value());
-      if (!convertedType)
-        return mlir::failure();
-      signatureConversion.addInputs(argType.index(), convertedType);
-    }
+    if (fnType.isVarArg()) {
+      // TODO: once the func dialect supports variadic functions rewrite this
+      // For now only insert special handling of printf via the llvmir dialect
+      if (op.getSymName().equals_insensitive("printf")) {
+        auto context = rewriter.getContext();
+        // Create a llvmir dialect function declaration for printf, the
+        // signature is: i32 (!llvm.ptr, ...)
+        auto llvmI32Ty = mlir::IntegerType::get(context, 32);
+        auto llvmPtrTy = mlir::LLVM::LLVMPointerType::get(context);
+        auto llvmFnType =
+            mlir::LLVM::LLVMFunctionType::get(llvmI32Ty, llvmPtrTy,
+                                              /*isVarArg=*/true);
+        auto printfFunc = rewriter.create<mlir::LLVM::LLVMFuncOp>(
+            op.getLoc(), "printf", llvmFnType);
+        rewriter.replaceOp(op, printfFunc);
+      } else {
+        rewriter.eraseOp(op);
+        return op.emitError() << "lowering of variadic functions (except "
+                                 "printf) not supported yet";
+      }
+    } else {
+      mlir::TypeConverter::SignatureConversion signatureConversion(
+          fnType.getNumInputs());
+
+      for (const auto &argType : enumerate(fnType.getInputs())) {
+        auto convertedType = typeConverter->convertType(argType.value());
+        if (!convertedType)
+          return mlir::failure();
+        signatureConversion.addInputs(argType.index(), convertedType);
+      }
 
-    SmallVector<mlir::NamedAttribute, 2> passThroughAttrs;
+      SmallVector<mlir::NamedAttribute, 2> passThroughAttrs;
 
-    if (auto symVisibilityAttr = op.getSymVisibilityAttr())
-      passThroughAttrs.push_back(
-          rewriter.getNamedAttr("sym_visibility", symVisibilityAttr));
+      if (auto symVisibilityAttr = op.getSymVisibilityAttr())
+        passThroughAttrs.push_back(
+            rewriter.getNamedAttr("sym_visibility", symVisibilityAttr));
 
-    mlir::Type resultType =
-        getTypeConverter()->convertType(fnType.getReturnType());
-    auto fn = rewriter.create<mlir::func::FuncOp>(
-        op.getLoc(), op.getName(),
-        rewriter.getFunctionType(signatureConversion.getConvertedTypes(),
-                                 resultType ? mlir::TypeRange(resultType)
-                                            : mlir::TypeRange()),
-        passThroughAttrs);
+      mlir::Type resultType =
+          getTypeConverter()->convertType(fnType.getReturnType());
+      auto fn = rewriter.create<mlir::func::FuncOp>(
+          op.getLoc(), op.getName(),
+          rewriter.getFunctionType(signatureConversion.getConvertedTypes(),
+                                   resultType ? mlir::TypeRange(resultType)
+                                              : mlir::TypeRange()),
+          passThroughAttrs);
 
-    if (failed(rewriter.convertRegionTypes(&op.getBody(), *typeConverter,
-                                           &signatureConversion)))
-      return mlir::failure();
-    rewriter.inlineRegionBefore(op.getBody(), fn.getBody(), fn.end());
+      if (failed(rewriter.convertRegionTypes(&op.getBody(), *typeConverter,
+                                             &signatureConversion)))
+        return mlir::failure();
+      rewriter.inlineRegionBefore(op.getBody(), fn.getBody(), fn.end());
 
-    rewriter.eraseOp(op);
+      rewriter.eraseOp(op);
+    }
     return mlir::LogicalResult::success();
   }
 };

clang/test/CIR/Lowering/ThroughMLIR/call.c

@@ -12,3 +12,41 @@ int test(void) {
 //       CHECK:   %[[ARG:.+]] = arith.constant 2 : i32
 //  CHECK-NEXT:   call @foo(%[[ARG]]) : (i32) -> ()
 //       CHECK: }
+
+extern int printf(const char *str, ...);
+
+// CHECK-LABEL: llvm.func @printf(!llvm.ptr, ...) -> i32
+//       CHECK: llvm.mlir.global internal constant @[[FRMT_STR:.*]](dense<[37, 100, 44, 32, 37, 102, 44, 32, 37, 100, 44, 32, 37, 108, 108, 100, 44, 32, 37, 100, 44, 32, 37, 102, 10, 0]> : tensor<26xi8>) {addr_space = 0 : i32} : !llvm.array<26 x i8>
+
+void testfunc(short s, float X, char C, long long LL, int I, double D) {
+	printf("%d, %f, %d, %lld, %d, %f\n", s, X, C, LL, I, D);
+}
+
+// CHECK: func.func @testfunc(%[[ARG0:.*]]: i16 {{.*}}, %[[ARG1:.*]]: f32 {{.*}}, %[[ARG2:.*]]: i8 {{.*}}, %[[ARG3:.*]]: i64 {{.*}}, %[[ARG4:.*]]: i32 {{.*}}, %[[ARG5:.*]]: f64 {{.*}}) {
+// CHECK: %[[ALLOCA_S:.*]] = memref.alloca() {alignment = 2 : i64} : memref<i16>
+// CHECK: %[[ALLOCA_X:.*]] = memref.alloca() {alignment = 4 : i64} : memref<f32>  
+// CHECK: %[[ALLOCA_C:.*]] = memref.alloca() {alignment = 1 : i64} : memref<i8> 
+// CHECK: %[[ALLOCA_LL:.*]] = memref.alloca() {alignment = 8 : i64} : memref<i64> 
+// CHECK: %[[ALLOCA_I:.*]] = memref.alloca() {alignment = 4 : i64} : memref<i32> 
+// CHECK: %[[ALLOCA_D:.*]] = memref.alloca() {alignment = 8 : i64} : memref<f64> 
+// CHECK: memref.store %[[ARG0]], %[[ALLOCA_S]][] : memref<i16> 
+// CHECK: memref.store %[[ARG1]], %[[ALLOCA_X]][] : memref<f32>
+// CHECK: memref.store %[[ARG2]], %[[ALLOCA_C]][] : memref<i8> 
+// CHECK: memref.store %[[ARG3]], %[[ALLOCA_LL]][] : memref<i64> 
+// CHECK: memref.store %[[ARG4]], %[[ALLOCA_I]][] : memref<i32> 
+// CHECK: memref.store %[[ARG5]], %[[ALLOCA_D]][] : memref<f64> 
+// CHECK: %[[FRMT_STR_ADDR:.*]] = llvm.mlir.addressof @[[FRMT_STR]] : !llvm.ptr 
+// CHECK: %[[C0:.*]] = llvm.mlir.constant(0 : index) : i8 
+// CHECK: %[[FRMT_STR_DATA:.*]] = llvm.getelementptr %[[FRMT_STR_ADDR]][%[[C0]], %[[C0]]] : (!llvm.ptr, i8, i8) -> !llvm.ptr, !llvm.array<26 x i8> 
+// CHECK: %[[S:.*]] = memref.load %[[ALLOCA_S]][] : memref<i16> 
+// CHECK: %[[S_EXT:.*]] = arith.extsi %3 : i16 to i32 
+// CHECK: %[[X:.*]] = memref.load %[[ALLOCA_X]][] : memref<f32> 
+// CHECK: %[[X_EXT:.*]] = arith.extf %5 : f32 to f64 
+// CHECK: %[[C:.*]] = memref.load %[[ALLOCA_C]][] : memref<i8> 
+// CHECK: %[[C_EXT:.*]] = arith.extsi %7 : i8 to i32
+// CHECK: %[[LL:.*]] = memref.load %[[ALLOCA_LL]][] : memref<i64> 
+// CHECK: %[[I:.*]] = memref.load %[[ALLOCA_I]][] : memref<i32> 
+// CHECK: %[[D:.*]] = memref.load %[[ALLOCA_D]][] : memref<f64> 
+// CHECK: {{.*}} = llvm.call @printf(%[[FRMT_STR_DATA]], %[[S_EXT]], %[[X_EXT]], %[[C_EXT]], %[[LL]], %[[I]], %[[D]]) vararg(!llvm.func<i32 (ptr, ...)>) : (!llvm.ptr, i32, f64, i32, i64, i32, f64) -> i32 
+// CHECK: return
+// CHECK: }