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 occurences 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 //===----------------------------------------------------------------------===//
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/ADT/StringMap.h"
20 #include "llvm/Pass.h"
21 #include "llvm/IR/Function.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/IR/Type.h"
24 #include "llvm/IR/DerivedTypes.h"
25 #include "llvm/IR/Instructions.h"
26 #include "llvm/IR/Constants.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/raw_os_ostream.h"
30 #include "llvm/Transforms/Scalar.h"
36 #define NVVM_REFLECT_FUNCTION "__nvvm_reflect"
40 namespace llvm { void initializeNVVMReflectPass(PassRegistry &); }
43 class LLVM_LIBRARY_VISIBILITY NVVMReflect : public ModulePass {
45 StringMap<int> VarMap;
46 typedef DenseMap<std::string, int>::iterator VarMapIter;
47 Function *ReflectFunction;
51 NVVMReflect() : ModulePass(ID) {
56 void getAnalysisUsage(AnalysisUsage &AU) const { AU.setPreservesAll(); }
57 virtual bool runOnModule(Module &);
64 NVVMReflectEnabled("nvvm-reflect-enable", cl::init(true),
65 cl::desc("NVVM reflection, enabled by default"));
67 char NVVMReflect::ID = 0;
68 INITIALIZE_PASS(NVVMReflect, "nvvm-reflect",
69 "Replace occurences of __nvvm_reflect() calls with 0/1", false,
72 static cl::list<std::string>
73 ReflectList("nvvm-reflect-list", cl::value_desc("name=<int>"),
74 cl::desc("A list of string=num assignments"),
77 /// The command line can look as follows :
78 /// -nvvm-reflect-list a=1,b=2 -nvvm-reflect-list c=3,d=0 -R e=2
79 /// The strings "a=1,b=2", "c=3,d=0", "e=2" are available in the
80 /// ReflectList vector. First, each of ReflectList[i] is 'split'
81 /// using "," as the delimiter. Then each of this part is split
82 /// using "=" as the delimiter.
83 void NVVMReflect::setVarMap() {
84 for (unsigned i = 0, e = ReflectList.size(); i != e; ++i) {
85 DEBUG(dbgs() << "Option : " << ReflectList[i] << "\n");
86 SmallVector<StringRef, 4> NameValList;
87 StringRef(ReflectList[i]).split(NameValList, ",");
88 for (unsigned j = 0, ej = NameValList.size(); j != ej; ++j) {
89 SmallVector<StringRef, 2> NameValPair;
90 NameValList[j].split(NameValPair, "=");
91 assert(NameValPair.size() == 2 && "name=val expected");
92 std::stringstream ValStream(NameValPair[1]);
95 assert((!(ValStream.fail())) && "integer value expected");
96 VarMap[NameValPair[0]] = Val;
101 bool NVVMReflect::runOnModule(Module &M) {
102 if (!NVVMReflectEnabled)
107 ReflectFunction = M.getFunction(NVVM_REFLECT_FUNCTION);
109 // If reflect function is not used, then there will be
110 // no entry in the module.
111 if (ReflectFunction == 0)
114 // Validate _reflect function
115 assert(ReflectFunction->isDeclaration() &&
116 "_reflect function should not have a body");
117 assert(ReflectFunction->getReturnType()->isIntegerTy() &&
118 "_reflect's return type should be integer");
120 std::vector<Instruction *> ToRemove;
122 // Go through the uses of ReflectFunction in this Function.
123 // Each of them should a CallInst with a ConstantArray argument.
124 // First validate that. If the c-string corresponding to the
125 // ConstantArray can be found successfully, see if it can be
126 // found in VarMap. If so, replace the uses of CallInst with the
127 // value found in VarMap. If not, replace the use with value 0.
128 for (Value::use_iterator I = ReflectFunction->use_begin(),
129 E = ReflectFunction->use_end();
131 assert(isa<CallInst>(*I) && "Only a call instruction can use _reflect");
132 CallInst *Reflect = cast<CallInst>(*I);
134 assert((Reflect->getNumOperands() == 2) &&
135 "Only one operand expect for _reflect function");
136 // In cuda, we will have an extra constant-to-generic conversion of
138 const Value *conv = Reflect->getArgOperand(0);
139 assert(isa<CallInst>(conv) && "Expected a const-to-gen conversion");
140 const CallInst *ConvCall = cast<CallInst>(conv);
141 const Value *str = ConvCall->getArgOperand(0);
142 assert(isa<ConstantExpr>(str) &&
143 "Format of _reflect function not recognized");
144 const ConstantExpr *GEP = cast<ConstantExpr>(str);
146 const Value *Sym = GEP->getOperand(0);
147 assert(isa<Constant>(Sym) && "Format of _reflect function not recognized");
149 const Constant *SymStr = cast<Constant>(Sym);
151 assert(isa<ConstantDataSequential>(SymStr->getOperand(0)) &&
152 "Format of _reflect function not recognized");
154 assert(cast<ConstantDataSequential>(SymStr->getOperand(0))->isCString() &&
155 "Format of _reflect function not recognized");
157 std::string ReflectArg =
158 cast<ConstantDataSequential>(SymStr->getOperand(0))->getAsString();
160 ReflectArg = ReflectArg.substr(0, ReflectArg.size() - 1);
161 DEBUG(dbgs() << "Arg of _reflect : " << ReflectArg << "\n");
163 int ReflectVal = 0; // The default value is 0
164 if (VarMap.find(ReflectArg) != VarMap.end()) {
165 ReflectVal = VarMap[ReflectArg];
167 Reflect->replaceAllUsesWith(
168 ConstantInt::get(Reflect->getType(), ReflectVal));
169 ToRemove.push_back(Reflect);
171 if (ToRemove.size() == 0)
174 for (unsigned i = 0, e = ToRemove.size(); i != e; ++i)
175 ToRemove[i]->eraseFromParent();