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+//===- NVVMReflect.cpp - NVVM Emulate conditional compilation -------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass replaces occurrences of __nvvm_reflect("string") with an
+// integer based on -nvvm-reflect-list string=<int> option given to this pass.
+// If an undefined string value is seen in a call to __nvvm_reflect("string"),
+// a default value of 0 will be used.
+//
+//===----------------------------------------------------------------------===//
+
+#include "NVPTX.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_os_ostream.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar.h"
+#include <map>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#define NVVM_REFLECT_FUNCTION "__nvvm_reflect"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "nvptx-reflect"
+
+namespace llvm { void initializeNVVMReflectPass(PassRegistry &); }
+
+namespace {
+class NVVMReflect : public ModulePass {
+private:
+ StringMap<int> VarMap;
+ typedef DenseMap<std::string, int>::iterator VarMapIter;
+
+public:
+ static char ID;
+ NVVMReflect() : ModulePass(ID) {
+ initializeNVVMReflectPass(*PassRegistry::getPassRegistry());
+ VarMap.clear();
+ }
+
+ NVVMReflect(const StringMap<int> &Mapping)
+ : ModulePass(ID) {
+ initializeNVVMReflectPass(*PassRegistry::getPassRegistry());
+ for (StringMap<int>::const_iterator I = Mapping.begin(), E = Mapping.end();
+ I != E; ++I) {
+ VarMap[(*I).getKey()] = (*I).getValue();
+ }
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.setPreservesAll();
+ }
+ bool runOnModule(Module &) override;
+
+private:
+ bool handleFunction(Function *ReflectFunction);
+ void setVarMap();
+};
+}
+
+ModulePass *llvm::createNVVMReflectPass() {
+ return new NVVMReflect();
+}
+
+ModulePass *llvm::createNVVMReflectPass(const StringMap<int>& Mapping) {
+ return new NVVMReflect(Mapping);
+}
+
+static cl::opt<bool>
+NVVMReflectEnabled("nvvm-reflect-enable", cl::init(true), cl::Hidden,
+ cl::desc("NVVM reflection, enabled by default"));
+
+char NVVMReflect::ID = 0;
+INITIALIZE_PASS(NVVMReflect, "nvvm-reflect",
+ "Replace occurrences of __nvvm_reflect() calls with 0/1", false,
+ false)
+
+static cl::list<std::string>
+ReflectList("nvvm-reflect-list", cl::value_desc("name=<int>"), cl::Hidden,
+ cl::desc("A list of string=num assignments"),
+ cl::ValueRequired);
+
+/// The command line can look as follows :
+/// -nvvm-reflect-list a=1,b=2 -nvvm-reflect-list c=3,d=0 -R e=2
+/// The strings "a=1,b=2", "c=3,d=0", "e=2" are available in the
+/// ReflectList vector. First, each of ReflectList[i] is 'split'
+/// using "," as the delimiter. Then each of this part is split
+/// using "=" as the delimiter.
+void NVVMReflect::setVarMap() {
+ for (unsigned i = 0, e = ReflectList.size(); i != e; ++i) {
+ DEBUG(dbgs() << "Option : " << ReflectList[i] << "\n");
+ SmallVector<StringRef, 4> NameValList;
+ StringRef(ReflectList[i]).split(NameValList, ',');
+ for (unsigned j = 0, ej = NameValList.size(); j != ej; ++j) {
+ SmallVector<StringRef, 2> NameValPair;
+ NameValList[j].split(NameValPair, '=');
+ assert(NameValPair.size() == 2 && "name=val expected");
+ std::stringstream ValStream(NameValPair[1]);
+ int Val;
+ ValStream >> Val;
+ assert((!(ValStream.fail())) && "integer value expected");
+ VarMap[NameValPair[0]] = Val;
+ }
+ }
+}
+
+bool NVVMReflect::handleFunction(Function *ReflectFunction) {
+ // Validate _reflect function
+ assert(ReflectFunction->isDeclaration() &&
+ "_reflect function should not have a body");
+ assert(ReflectFunction->getReturnType()->isIntegerTy() &&
+ "_reflect's return type should be integer");
+
+ std::vector<Instruction *> ToRemove;
+
+ // Go through the uses of ReflectFunction in this Function.
+ // Each of them should a CallInst with a ConstantArray argument.
+ // First validate that. If the c-string corresponding to the
+ // ConstantArray can be found successfully, see if it can be
+ // found in VarMap. If so, replace the uses of CallInst with the
+ // value found in VarMap. If not, replace the use with value 0.
+
+ // IR for __nvvm_reflect calls differs between CUDA versions:
+ // CUDA 6.5 and earlier uses this sequence:
+ // %ptr = tail call i8* @llvm.nvvm.ptr.constant.to.gen.p0i8.p4i8
+ // (i8 addrspace(4)* getelementptr inbounds
+ // ([8 x i8], [8 x i8] addrspace(4)* @str, i32 0, i32 0))
+ // %reflect = tail call i32 @__nvvm_reflect(i8* %ptr)
+ //
+ // Value returned by Sym->getOperand(0) is a Constant with a
+ // ConstantDataSequential operand which can be converted to string and used
+ // for lookup.
+ //
+ // CUDA 7.0 does it slightly differently:
+ // %reflect = call i32 @__nvvm_reflect(i8* addrspacecast
+ // (i8 addrspace(1)* getelementptr inbounds
+ // ([8 x i8], [8 x i8] addrspace(1)* @str, i32 0, i32 0) to i8*))
+ //
+ // In this case, we get a Constant with a GlobalVariable operand and we need
+ // to dig deeper to find its initializer with the string we'll use for lookup.
+
+ for (User *U : ReflectFunction->users()) {
+ assert(isa<CallInst>(U) && "Only a call instruction can use _reflect");
+ CallInst *Reflect = cast<CallInst>(U);
+
+ assert((Reflect->getNumOperands() == 2) &&
+ "Only one operand expect for _reflect function");
+ // In cuda, we will have an extra constant-to-generic conversion of
+ // the string.
+ const Value *Str = Reflect->getArgOperand(0);
+ if (isa<CallInst>(Str)) {
+ // CUDA path
+ const CallInst *ConvCall = cast<CallInst>(Str);
+ Str = ConvCall->getArgOperand(0);
+ }
+ assert(isa<ConstantExpr>(Str) &&
+ "Format of _reflect function not recognized");
+ const ConstantExpr *GEP = cast<ConstantExpr>(Str);
+
+ const Value *Sym = GEP->getOperand(0);
+ assert(isa<Constant>(Sym) && "Format of _reflect function not recognized");
+
+ const Value *Operand = cast<Constant>(Sym)->getOperand(0);
+ if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(Operand)) {
+ // For CUDA-7.0 style __nvvm_reflect calls we need to find operand's
+ // initializer.
+ assert(GV->hasInitializer() &&
+ "Format of _reflect function not recognized");
+ const Constant *Initializer = GV->getInitializer();
+ Operand = Initializer;
+ }
+
+ assert(isa<ConstantDataSequential>(Operand) &&
+ "Format of _reflect function not recognized");
+ assert(cast<ConstantDataSequential>(Operand)->isCString() &&
+ "Format of _reflect function not recognized");
+
+ std::string ReflectArg =
+ cast<ConstantDataSequential>(Operand)->getAsString();
+
+ ReflectArg = ReflectArg.substr(0, ReflectArg.size() - 1);
+ DEBUG(dbgs() << "Arg of _reflect : " << ReflectArg << "\n");
+
+ int ReflectVal = 0; // The default value is 0
+ if (VarMap.find(ReflectArg) != VarMap.end()) {
+ ReflectVal = VarMap[ReflectArg];
+ }
+ Reflect->replaceAllUsesWith(
+ ConstantInt::get(Reflect->getType(), ReflectVal));
+ ToRemove.push_back(Reflect);
+ }
+ if (ToRemove.size() == 0)
+ return false;
+
+ for (unsigned i = 0, e = ToRemove.size(); i != e; ++i)
+ ToRemove[i]->eraseFromParent();
+ return true;
+}
+
+bool NVVMReflect::runOnModule(Module &M) {
+ if (!NVVMReflectEnabled)
+ return false;
+
+ setVarMap();
+
+
+ bool Res = false;
+ std::string Name;
+ Type *Tys[1];
+ Type *I8Ty = Type::getInt8Ty(M.getContext());
+ Function *ReflectFunction;
+
+ // Check for standard overloaded versions of llvm.nvvm.reflect
+
+ for (unsigned i = 0; i != 5; ++i) {
+ Tys[0] = PointerType::get(I8Ty, i);
+ Name = Intrinsic::getName(Intrinsic::nvvm_reflect, Tys);
+ ReflectFunction = M.getFunction(Name);
+ if(ReflectFunction != 0) {
+ Res |= handleFunction(ReflectFunction);
+ }
+ }
+
+ ReflectFunction = M.getFunction(NVVM_REFLECT_FUNCTION);
+ // If reflect function is not used, then there will be
+ // no entry in the module.
+ if (ReflectFunction != 0)
+ Res |= handleFunction(ReflectFunction);
+
+ return Res;
+}
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