[OpenMP][NVPTX][CUDA] Adding support for printf for an NVPTX OpenMP device.

[arpith-jacob]

Summary

Support for CUDA printf is exploited to support printf for an NVPTX OpenMP device.

To reflect the support of both programming models, the file CGCUDABuiltin.cpp has been changed to CGGPUBuiltin.cpp, and the call EmitCUDADevicePrintfCallExpr has been changed to EmitGPUDevicePrintfCallExpr.

[jlebar]

Didn't look carefully at the test (let me know if you'd like me to). The rest looks good to me.

[arpith-jacob]

Thanks for the quick review! The test cases are the same as the CUDA version so it should be fine.

[Eugene.Zelenko]

Looks like patch was not committed.

cfe/trunk/lib/CodeGen/CGBuiltin.cpp

case Builtin::BIget_kernel_preferred_work_group_size_multiple: {
     Arg = Builder.CreatePointerCast(Arg, GenericVoidPtrTy);
     return RValue::get(Builder.CreateCall(
         CGM.CreateRuntimeFunction(
             llvm::FunctionType::get(IntTy, GenericVoidPtrTy, false),
             "__get_kernel_preferred_work_group_multiple_impl"),
         Arg));
   }
   case Builtin::BIprintf:
-    if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice)
-      return EmitCUDADevicePrintfCallExpr(E, ReturnValue);
+    if (getTarget().getTriple().isNVPTX())
+      return EmitNVPTXDevicePrintfCallExpr(E, ReturnValue);
     break;
   case Builtin::BI__builtin_canonicalize:
   case Builtin::BI__builtin_canonicalizef:
   case Builtin::BI__builtin_canonicalizel:
     return RValue::get(emitUnaryBuiltin(*this, E, Intrinsic::canonicalize));
 
   case Builtin::BI__builtin_thread_pointer: {
     if (!getContext().getTargetInfo().isTLSSupported())

cfe/trunk/lib/CodeGen/CGCUDABuiltin.cpp

-//===----- CGCUDABuiltin.cpp - Codegen for CUDA builtins ------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// Generates code for built-in CUDA calls which are not runtime-specific.
-// (Runtime-specific codegen lives in CGCUDARuntime.)
-//
-//===----------------------------------------------------------------------===//
-
-#include "CodeGenFunction.h"
-#include "clang/Basic/Builtins.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/Instruction.h"
-#include "llvm/Support/MathExtras.h"
-
-using namespace clang;
-using namespace CodeGen;
-
-static llvm::Function *GetVprintfDeclaration(llvm::Module &M) {
-  llvm::Type *ArgTypes[] = {llvm::Type::getInt8PtrTy(M.getContext()),
-                            llvm::Type::getInt8PtrTy(M.getContext())};
-  llvm::FunctionType *VprintfFuncType = llvm::FunctionType::get(
-      llvm::Type::getInt32Ty(M.getContext()), ArgTypes, false);
-
-  if (auto* F = M.getFunction("vprintf")) {
-    // Our CUDA system header declares vprintf with the right signature, so
-    // nobody else should have been able to declare vprintf with a bogus
-    // signature.
-    assert(F->getFunctionType() == VprintfFuncType);
-    return F;
-  }
-
-  // vprintf doesn't already exist; create a declaration and insert it into the
-  // module.
-  return llvm::Function::Create(
-      VprintfFuncType, llvm::GlobalVariable::ExternalLinkage, "vprintf", &M);
-}
-
-// Transforms a call to printf into a call to the NVPTX vprintf syscall (which
-// isn't particularly special; it's invoked just like a regular function).
-// vprintf takes two args: A format string, and a pointer to a buffer containing
-// the varargs.
-//
-// For example, the call
-//
-//   printf("format string", arg1, arg2, arg3);
-//
-// is converted into something resembling
-//
-//   struct Tmp {
-//     Arg1 a1;
-//     Arg2 a2;
-//     Arg3 a3;
-//   };
-//   char* buf = alloca(sizeof(Tmp));
-//   *(Tmp*)buf = {a1, a2, a3};
-//   vprintf("format string", buf);
-//
-// buf is aligned to the max of {alignof(Arg1), ...}.  Furthermore, each of the
-// args is itself aligned to its preferred alignment.
-//
-// Note that by the time this function runs, E's args have already undergone the
-// standard C vararg promotion (short -> int, float -> double, etc.).
-RValue
-CodeGenFunction::EmitCUDADevicePrintfCallExpr(const CallExpr *E,
-                                              ReturnValueSlot ReturnValue) {
-  assert(getLangOpts().CUDA);
-  assert(getLangOpts().CUDAIsDevice);
-  assert(E->getBuiltinCallee() == Builtin::BIprintf);
-  assert(E->getNumArgs() >= 1); // printf always has at least one arg.
-
-  const llvm::DataLayout &DL = CGM.getDataLayout();
-  llvm::LLVMContext &Ctx = CGM.getLLVMContext();
-
-  CallArgList Args;
-  EmitCallArgs(Args,
-               E->getDirectCallee()->getType()->getAs<FunctionProtoType>(),
-               E->arguments(), E->getDirectCallee(),
-               /* ParamsToSkip = */ 0);
-
-  // We don't know how to emit non-scalar varargs.
-  if (std::any_of(Args.begin() + 1, Args.end(),
-                  [](const CallArg &A) { return !A.RV.isScalar(); })) {
-    CGM.ErrorUnsupported(E, "non-scalar arg to printf");
-    return RValue::get(llvm::ConstantInt::get(IntTy, 0));
-  }
-
-  // Construct and fill the args buffer that we'll pass to vprintf.
-  llvm::Value *BufferPtr;
-  if (Args.size() <= 1) {
-    // If there are no args, pass a null pointer to vprintf.
-    BufferPtr = llvm::ConstantPointerNull::get(llvm::Type::getInt8PtrTy(Ctx));
-  } else {
-    llvm::SmallVector<llvm::Type *, 8> ArgTypes;
-    for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I)
-      ArgTypes.push_back(Args[I].RV.getScalarVal()->getType());
-
-    // Using llvm::StructType is correct only because printf doesn't accept
-    // aggregates.  If we had to handle aggregates here, we'd have to manually
-    // compute the offsets within the alloca -- we wouldn't be able to assume
-    // that the alignment of the llvm type was the same as the alignment of the
-    // clang type.
-    llvm::Type *AllocaTy = llvm::StructType::create(ArgTypes, "printf_args");
-    llvm::Value *Alloca = CreateTempAlloca(AllocaTy);
-
-    for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I) {
-      llvm::Value *P = Builder.CreateStructGEP(AllocaTy, Alloca, I - 1);
-      llvm::Value *Arg = Args[I].RV.getScalarVal();
-      Builder.CreateAlignedStore(Arg, P, DL.getPrefTypeAlignment(Arg->getType()));
-    }
-    BufferPtr = Builder.CreatePointerCast(Alloca, llvm::Type::getInt8PtrTy(Ctx));
-  }
-
-  // Invoke vprintf and return.
-  llvm::Function* VprintfFunc = GetVprintfDeclaration(CGM.getModule());
-  return RValue::get(
-      Builder.CreateCall(VprintfFunc, {Args[0].RV.getScalarVal(), BufferPtr}));
-}

cfe/trunk/lib/CodeGen/CGGPUBuiltin.cpp

+//===------ CGGPUBuiltin.cpp - Codegen for GPU builtins -------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Generates code for built-in GPU calls which are not runtime-specific.
+// (Runtime-specific codegen lives in programming model specific files.)
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "clang/Basic/Builtins.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/Support/MathExtras.h"
+
+using namespace clang;
+using namespace CodeGen;
+
+static llvm::Function *GetVprintfDeclaration(llvm::Module &M) {
+  llvm::Type *ArgTypes[] = {llvm::Type::getInt8PtrTy(M.getContext()),
+                            llvm::Type::getInt8PtrTy(M.getContext())};
+  llvm::FunctionType *VprintfFuncType = llvm::FunctionType::get(
+      llvm::Type::getInt32Ty(M.getContext()), ArgTypes, false);
+
+  if (auto* F = M.getFunction("vprintf")) {
+    // Our CUDA system header declares vprintf with the right signature, so
+    // nobody else should have been able to declare vprintf with a bogus
+    // signature.
+    assert(F->getFunctionType() == VprintfFuncType);
+    return F;
+  }
+
+  // vprintf doesn't already exist; create a declaration and insert it into the
+  // module.
+  return llvm::Function::Create(
+      VprintfFuncType, llvm::GlobalVariable::ExternalLinkage, "vprintf", &M);
+}
+
+// Transforms a call to printf into a call to the NVPTX vprintf syscall (which
+// isn't particularly special; it's invoked just like a regular function).
+// vprintf takes two args: A format string, and a pointer to a buffer containing
+// the varargs.
+//
+// For example, the call
+//
+//   printf("format string", arg1, arg2, arg3);
+//
+// is converted into something resembling
+//
+//   struct Tmp {
+//     Arg1 a1;
+//     Arg2 a2;
+//     Arg3 a3;
+//   };
+//   char* buf = alloca(sizeof(Tmp));
+//   *(Tmp*)buf = {a1, a2, a3};
+//   vprintf("format string", buf);
+//
+// buf is aligned to the max of {alignof(Arg1), ...}.  Furthermore, each of the
+// args is itself aligned to its preferred alignment.
+//
+// Note that by the time this function runs, E's args have already undergone the
+// standard C vararg promotion (short -> int, float -> double, etc.).
+RValue
+CodeGenFunction::EmitNVPTXDevicePrintfCallExpr(const CallExpr *E,
+                                               ReturnValueSlot ReturnValue) {
+  assert(getTarget().getTriple().isNVPTX());
+  assert(E->getBuiltinCallee() == Builtin::BIprintf);
+  assert(E->getNumArgs() >= 1); // printf always has at least one arg.
+
+  const llvm::DataLayout &DL = CGM.getDataLayout();
+  llvm::LLVMContext &Ctx = CGM.getLLVMContext();
+
+  CallArgList Args;
+  EmitCallArgs(Args,
+               E->getDirectCallee()->getType()->getAs<FunctionProtoType>(),
+               E->arguments(), E->getDirectCallee(),
+               /* ParamsToSkip = */ 0);
+
+  // We don't know how to emit non-scalar varargs.
+  if (std::any_of(Args.begin() + 1, Args.end(),
+                  [](const CallArg &A) { return !A.RV.isScalar(); })) {
+    CGM.ErrorUnsupported(E, "non-scalar arg to printf");
+    return RValue::get(llvm::ConstantInt::get(IntTy, 0));
+  }
+
+  // Construct and fill the args buffer that we'll pass to vprintf.
+  llvm::Value *BufferPtr;
+  if (Args.size() <= 1) {
+    // If there are no args, pass a null pointer to vprintf.
+    BufferPtr = llvm::ConstantPointerNull::get(llvm::Type::getInt8PtrTy(Ctx));
+  } else {
+    llvm::SmallVector<llvm::Type *, 8> ArgTypes;
+    for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I)
+      ArgTypes.push_back(Args[I].RV.getScalarVal()->getType());
+
+    // Using llvm::StructType is correct only because printf doesn't accept
+    // aggregates.  If we had to handle aggregates here, we'd have to manually
+    // compute the offsets within the alloca -- we wouldn't be able to assume
+    // that the alignment of the llvm type was the same as the alignment of the
+    // clang type.
+    llvm::Type *AllocaTy = llvm::StructType::create(ArgTypes, "printf_args");
+    llvm::Value *Alloca = CreateTempAlloca(AllocaTy);
+
+    for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I) {
+      llvm::Value *P = Builder.CreateStructGEP(AllocaTy, Alloca, I - 1);
+      llvm::Value *Arg = Args[I].RV.getScalarVal();
+      Builder.CreateAlignedStore(Arg, P, DL.getPrefTypeAlignment(Arg->getType()));
+    }
+    BufferPtr = Builder.CreatePointerCast(Alloca, llvm::Type::getInt8PtrTy(Ctx));
+  }
+
+  // Invoke vprintf and return.
+  llvm::Function* VprintfFunc = GetVprintfDeclaration(CGM.getModule());
+  return RValue::get(
+      Builder.CreateCall(VprintfFunc, {Args[0].RV.getScalarVal(), BufferPtr}));
+}

cfe/trunk/lib/CodeGen/CMakeLists.txt

if (CLANG_BUILT_STANDALONE)
   set(codegen_deps)
 endif()
 
 add_clang_library(clangCodeGen
   BackendUtil.cpp
   CGAtomic.cpp
   CGBlocks.cpp
   CGBuiltin.cpp
-  CGCUDABuiltin.cpp
   CGCUDANV.cpp
   CGCUDARuntime.cpp
   CGCXX.cpp
   CGCXXABI.cpp
   CGCall.cpp
   CGClass.cpp
   CGCleanup.cpp
   CGCoroutine.cpp
   CGDebugInfo.cpp
   CGDecl.cpp
   CGDeclCXX.cpp
   CGException.cpp
   CGExpr.cpp
   CGExprAgg.cpp
   CGExprCXX.cpp
   CGExprComplex.cpp
   CGExprConstant.cpp
   CGExprScalar.cpp
+  CGGPUBuiltin.cpp
   CGLoopInfo.cpp
   CGObjC.cpp
   CGObjCGNU.cpp
   CGObjCMac.cpp
   CGObjCRuntime.cpp
   CGOpenCLRuntime.cpp
   CGOpenMPRuntime.cpp
   CGOpenMPRuntimeNVPTX.cpp

cfe/trunk/lib/CodeGen/CodeGenFunction.h

public:
   RValue EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
                                        const CXXMethodDecl *MD,
                                        ReturnValueSlot ReturnValue);
   RValue EmitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr *E);
 
   RValue EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
                                 ReturnValueSlot ReturnValue);
 
-  RValue EmitCUDADevicePrintfCallExpr(const CallExpr *E,
+  RValue EmitNVPTXDevicePrintfCallExpr(const CallExpr *E,
                                        ReturnValueSlot ReturnValue);
 
   RValue EmitBuiltinExpr(const FunctionDecl *FD,
                          unsigned BuiltinID, const CallExpr *E,
                          ReturnValueSlot ReturnValue);
 
   RValue EmitBlockCallExpr(const CallExpr *E, ReturnValueSlot ReturnValue);
 
   /// EmitTargetBuiltinExpr - Emit the given builtin call. Returns 0 if the call

cfe/trunk/test/OpenMP/nvptx_target_printf_codegen.c

+// Test target codegen - host bc file has to be created first.
+// RUN: %clang_cc1 -verify -fopenmp -x c -triple powerpc64le-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm-bc %s -o %t-ppc-host.bc
+// RUN: %clang_cc1 -verify -fopenmp -x c -triple nvptx64-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-ppc-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-64
+// RUN: %clang_cc1 -verify -fopenmp -x c -triple i386-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm-bc %s -o %t-x86-host.bc
+// RUN: %clang_cc1 -verify -fopenmp -x c -triple nvptx-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-x86-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-32
+
+#include <stdarg.h>
+
+// expected-no-diagnostics
+extern int printf(const char *, ...);
+extern int vprintf(const char *, va_list);
+
+// Check a simple call to printf end-to-end.
+// CHECK: [[SIMPLE_PRINTF_TY:%[a-zA-Z0-9_]+]] = type { i32, i64, double }
+int CheckSimple() {
+    // CHECK: define {{.*}}void [[T1:@__omp_offloading_.+CheckSimple.+]]_worker()
+#pragma omp target
+  {
+    // Entry point.
+    // CHECK: define {{.*}}void [[T1]]()
+    // Alloca in entry block.
+    // CHECK: [[BUF:%[a-zA-Z0-9_]+]] = alloca [[SIMPLE_PRINTF_TY]]
+
+    // CHECK: {{call|invoke}} void [[T1]]_worker()
+    // CHECK: br label {{%?}}[[EXIT:.+]]
+    //
+    // CHECK-DAG: [[CMTID:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.tid.x()
+    // CHECK-DAG: [[CMNTH:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.ntid.x()
+    // CHECK-DAG: [[CMWS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+    // CHECK: [[IS_MASTER:%.+]] = icmp eq i32 [[CMTID]],
+    // CHECK: br i1 [[IS_MASTER]], label {{%?}}[[MASTER:.+]], label {{%?}}[[EXIT]]
+    //
+    // CHECK: [[MASTER]]
+    // CHECK-DAG: [[MNTH:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.ntid.x()
+    // CHECK-DAG: [[MWS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+    // CHECK: [[MTMP1:%.+]] = sub i32 [[MNTH]], [[MWS]]
+    // CHECK: call void @__kmpc_kernel_init(i32 [[MTMP1]]
+
+    // printf in master-only basic block.
+    // CHECK: [[FMT:%[0-9]+]] = load{{.*}}%fmt
+    const char* fmt = "%d %lld %f";
+    // CHECK: [[PTR0:%[0-9]+]] = getelementptr inbounds [[SIMPLE_PRINTF_TY]], [[SIMPLE_PRINTF_TY]]* [[BUF]], i32 0, i32 0
+    // CHECK: store i32 1, i32* [[PTR0]], align 4
+    // CHECK: [[PTR1:%[0-9]+]] = getelementptr inbounds [[SIMPLE_PRINTF_TY]], [[SIMPLE_PRINTF_TY]]* [[BUF]], i32 0, i32 1
+    // CHECK: store i64 2, i64* [[PTR1]], align 8
+    // CHECK: [[PTR2:%[0-9]+]] = getelementptr inbounds [[SIMPLE_PRINTF_TY]], [[SIMPLE_PRINTF_TY]]* [[BUF]], i32 0, i32 2
+
+    // CHECK: store double 3.0{{[^,]*}}, double* [[PTR2]], align 8
+    // CHECK: [[BUF_CAST:%[0-9]+]] = bitcast [[SIMPLE_PRINTF_TY]]* [[BUF]] to i8*
+    // CHECK: [[RET:%[0-9]+]] = call i32 @vprintf(i8* [[FMT]], i8* [[BUF_CAST]])
+    printf(fmt, 1, 2ll, 3.0);
+  }
+
+  return 0;
+}
+
+void CheckNoArgs() {
+    // CHECK: define {{.*}}void [[T2:@__omp_offloading_.+CheckNoArgs.+]]_worker()
+#pragma omp target
+  {
+    // Entry point.
+    // CHECK: define {{.*}}void [[T2]]()
+
+    // CHECK: {{call|invoke}} void [[T2]]_worker()
+    // CHECK: br label {{%?}}[[EXIT:.+]]
+    //
+    // CHECK-DAG: [[CMTID:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.tid.x()
+    // CHECK-DAG: [[CMNTH:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.ntid.x()
+    // CHECK-DAG: [[CMWS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+    // CHECK: [[IS_MASTER:%.+]] = icmp eq i32 [[CMTID]],
+    // CHECK: br i1 [[IS_MASTER]], label {{%?}}[[MASTER:.+]], label {{%?}}[[EXIT]]
+    //
+    // CHECK: [[MASTER]]
+    // CHECK-DAG: [[MNTH:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.ntid.x()
+    // CHECK-DAG: [[MWS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+    // CHECK: [[MTMP1:%.+]] = sub i32 [[MNTH]], [[MWS]]
+    // CHECK: call void @__kmpc_kernel_init(i32 [[MTMP1]]
+
+    // printf in master-only basic block.
+    // CHECK: call i32 @vprintf({{.*}}, i8* null){{$}}
+    printf("hello, world!");
+  }
+}
+
+// Check that printf's alloca happens in the entry block, not inside the if
+// statement.
+int foo;
+void CheckAllocaIsInEntryBlock() {
+    // CHECK: define {{.*}}void [[T3:@__omp_offloading_.+CheckAllocaIsInEntryBlock.+]]_worker()
+#pragma omp target
+  {
+    // Entry point.
+    // CHECK: define {{.*}}void [[T3]](
+    // Alloca in entry block.
+    // CHECK: alloca %printf_args
+
+    // CHECK: {{call|invoke}} void [[T3]]_worker()
+    // CHECK: br label {{%?}}[[EXIT:.+]]
+    //
+    // CHECK-DAG: [[CMTID:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.tid.x()
+    // CHECK-DAG: [[CMNTH:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.ntid.x()
+    // CHECK-DAG: [[CMWS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+    // CHECK: [[IS_MASTER:%.+]] = icmp eq i32 [[CMTID]],
+    // CHECK: br i1 [[IS_MASTER]], label {{%?}}[[MASTER:.+]], label {{%?}}[[EXIT]]
+    //
+    // CHECK: [[MASTER]]
+    // CHECK-DAG: [[MNTH:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.ntid.x()
+    // CHECK-DAG: [[MWS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+    // CHECK: [[MTMP1:%.+]] = sub i32 [[MNTH]], [[MWS]]
+    // CHECK: call void @__kmpc_kernel_init(i32 [[MTMP1]]
+
+    if (foo) {
+      printf("%d", 42);
+    }
+  }
+}