1 //===- NVVMReflect.cpp - NVVM Emulate conditional compilation -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass replaces occurrences of __nvvm_reflect("string") with an
11 // integer based on -nvvm-reflect-list string=<int> option given to this pass.
12 // If an undefined string value is seen in a call to __nvvm_reflect("string"),
13 // a default value of 0 will be used.
15 //===----------------------------------------------------------------------===//
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/StringMap.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DerivedTypes.h"
23 #include "llvm/IR/Function.h"
24 #include "llvm/IR/Instructions.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/IR/Type.h"
27 #include "llvm/Pass.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/raw_os_ostream.h"
31 #include "llvm/Transforms/Scalar.h"
37 #define NVVM_REFLECT_FUNCTION "__nvvm_reflect"
41 #define DEBUG_TYPE "nvptx-reflect"
43 namespace llvm { void initializeNVVMReflectPass(PassRegistry &); }
46 class NVVMReflect : public ModulePass {
48 StringMap<int> VarMap;
49 typedef DenseMap<std::string, int>::iterator VarMapIter;
50 Function *ReflectFunction;
54 NVVMReflect() : ModulePass(ID), ReflectFunction(nullptr) {
55 initializeNVVMReflectPass(*PassRegistry::getPassRegistry());
59 NVVMReflect(const StringMap<int> &Mapping)
60 : ModulePass(ID), ReflectFunction(nullptr) {
61 initializeNVVMReflectPass(*PassRegistry::getPassRegistry());
62 for (StringMap<int>::const_iterator I = Mapping.begin(), E = Mapping.end();
64 VarMap[(*I).getKey()] = (*I).getValue();
68 void getAnalysisUsage(AnalysisUsage &AU) const override {
71 bool runOnModule(Module &) override;
77 ModulePass *llvm::createNVVMReflectPass() {
78 return new NVVMReflect();
81 ModulePass *llvm::createNVVMReflectPass(const StringMap<int>& Mapping) {
82 return new NVVMReflect(Mapping);
86 NVVMReflectEnabled("nvvm-reflect-enable", cl::init(true), cl::Hidden,
87 cl::desc("NVVM reflection, enabled by default"));
89 char NVVMReflect::ID = 0;
90 INITIALIZE_PASS(NVVMReflect, "nvvm-reflect",
91 "Replace occurrences of __nvvm_reflect() calls with 0/1", false,
94 static cl::list<std::string>
95 ReflectList("nvvm-reflect-list", cl::value_desc("name=<int>"), cl::Hidden,
96 cl::desc("A list of string=num assignments"),
99 /// The command line can look as follows :
100 /// -nvvm-reflect-list a=1,b=2 -nvvm-reflect-list c=3,d=0 -R e=2
101 /// The strings "a=1,b=2", "c=3,d=0", "e=2" are available in the
102 /// ReflectList vector. First, each of ReflectList[i] is 'split'
103 /// using "," as the delimiter. Then each of this part is split
104 /// using "=" as the delimiter.
105 void NVVMReflect::setVarMap() {
106 for (unsigned i = 0, e = ReflectList.size(); i != e; ++i) {
107 DEBUG(dbgs() << "Option : " << ReflectList[i] << "\n");
108 SmallVector<StringRef, 4> NameValList;
109 StringRef(ReflectList[i]).split(NameValList, ",");
110 for (unsigned j = 0, ej = NameValList.size(); j != ej; ++j) {
111 SmallVector<StringRef, 2> NameValPair;
112 NameValList[j].split(NameValPair, "=");
113 assert(NameValPair.size() == 2 && "name=val expected");
114 std::stringstream ValStream(NameValPair[1]);
117 assert((!(ValStream.fail())) && "integer value expected");
118 VarMap[NameValPair[0]] = Val;
123 bool NVVMReflect::runOnModule(Module &M) {
124 if (!NVVMReflectEnabled)
129 ReflectFunction = M.getFunction(NVVM_REFLECT_FUNCTION);
131 // If reflect function is not used, then there will be
132 // no entry in the module.
133 if (!ReflectFunction)
136 // Validate _reflect function
137 assert(ReflectFunction->isDeclaration() &&
138 "_reflect function should not have a body");
139 assert(ReflectFunction->getReturnType()->isIntegerTy() &&
140 "_reflect's return type should be integer");
142 std::vector<Instruction *> ToRemove;
144 // Go through the uses of ReflectFunction in this Function.
145 // Each of them should a CallInst with a ConstantArray argument.
146 // First validate that. If the c-string corresponding to the
147 // ConstantArray can be found successfully, see if it can be
148 // found in VarMap. If so, replace the uses of CallInst with the
149 // value found in VarMap. If not, replace the use with value 0.
150 for (User *U : ReflectFunction->users()) {
151 assert(isa<CallInst>(U) && "Only a call instruction can use _reflect");
152 CallInst *Reflect = cast<CallInst>(U);
154 assert((Reflect->getNumOperands() == 2) &&
155 "Only one operand expect for _reflect function");
156 // In cuda, we will have an extra constant-to-generic conversion of
158 const Value *conv = Reflect->getArgOperand(0);
159 assert(isa<CallInst>(conv) && "Expected a const-to-gen conversion");
160 const CallInst *ConvCall = cast<CallInst>(conv);
161 const Value *str = ConvCall->getArgOperand(0);
162 assert(isa<ConstantExpr>(str) &&
163 "Format of _reflect function not recognized");
164 const ConstantExpr *GEP = cast<ConstantExpr>(str);
166 const Value *Sym = GEP->getOperand(0);
167 assert(isa<Constant>(Sym) && "Format of _reflect function not recognized");
169 const Constant *SymStr = cast<Constant>(Sym);
171 assert(isa<ConstantDataSequential>(SymStr->getOperand(0)) &&
172 "Format of _reflect function not recognized");
174 assert(cast<ConstantDataSequential>(SymStr->getOperand(0))->isCString() &&
175 "Format of _reflect function not recognized");
177 std::string ReflectArg =
178 cast<ConstantDataSequential>(SymStr->getOperand(0))->getAsString();
180 ReflectArg = ReflectArg.substr(0, ReflectArg.size() - 1);
181 DEBUG(dbgs() << "Arg of _reflect : " << ReflectArg << "\n");
183 int ReflectVal = 0; // The default value is 0
184 if (VarMap.find(ReflectArg) != VarMap.end()) {
185 ReflectVal = VarMap[ReflectArg];
187 Reflect->replaceAllUsesWith(
188 ConstantInt::get(Reflect->getType(), ReflectVal));
189 ToRemove.push_back(Reflect);
191 if (ToRemove.size() == 0)
194 for (unsigned i = 0, e = ToRemove.size(); i != e; ++i)
195 ToRemove[i]->eraseFromParent();