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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/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/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;
Function *ReflectFunction;
public:
static char ID;
NVVMReflect() : ModulePass(ID), ReflectFunction(nullptr) {
initializeNVVMReflectPass(*PassRegistry::getPassRegistry());
VarMap.clear();
}
NVVMReflect(const StringMap<int> &Mapping)
: ModulePass(ID), ReflectFunction(nullptr) {
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;
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::runOnModule(Module &M) {
if (!NVVMReflectEnabled)
return false;
setVarMap();
ReflectFunction = M.getFunction(NVVM_REFLECT_FUNCTION);
// If reflect function is not used, then there will be
// no entry in the module.
if (!ReflectFunction)
return false;
// 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.
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 *conv = Reflect->getArgOperand(0);
assert(isa<CallInst>(conv) && "Expected a const-to-gen conversion");
const CallInst *ConvCall = cast<CallInst>(conv);
const Value *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 Constant *SymStr = cast<Constant>(Sym);
assert(isa<ConstantDataSequential>(SymStr->getOperand(0)) &&
"Format of _reflect function not recognized");
assert(cast<ConstantDataSequential>(SymStr->getOperand(0))->isCString() &&
"Format of _reflect function not recognized");
std::string ReflectArg =
cast<ConstantDataSequential>(SymStr->getOperand(0))->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;
}
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