llvm-6502/lib/Target/NVPTX/NVVMReflect.cpp

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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;
[Modules] Make Support/Debug.h modular. This requires it to not change behavior based on other files defining DEBUG_TYPE, which means it cannot define DEBUG_TYPE at all. This is actually better IMO as it forces folks to define relevant DEBUG_TYPEs for their files. However, it requires all files that currently use DEBUG(...) to define a DEBUG_TYPE if they don't already. I've updated all such files in LLVM and will do the same for other upstream projects. This still leaves one important change in how LLVM uses the DEBUG_TYPE macro going forward: we need to only define the macro *after* header files have been #include-ed. Previously, this wasn't possible because Debug.h required the macro to be pre-defined. This commit removes that. By defining DEBUG_TYPE after the includes two things are fixed: - Header files that need to provide a DEBUG_TYPE for some inline code can do so by defining the macro before their inline code and undef-ing it afterward so the macro does not escape. - We no longer have rampant ODR violations due to including headers with different DEBUG_TYPE definitions. This may be mostly an academic violation today, but with modules these types of violations are easy to check for and potentially very relevant. Where necessary to suppor headers with DEBUG_TYPE, I have moved the definitions below the includes in this commit. I plan to move the rest of the DEBUG_TYPE macros in LLVM in subsequent commits; this one is big enough. The comments in Debug.h, which were hilariously out of date already, have been updated to reflect the recommended practice going forward. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206822 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-21 22:55:11 +00:00
#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.
[C++11] Add range based accessors for the Use-Def chain of a Value. This requires a number of steps. 1) Move value_use_iterator into the Value class as an implementation detail 2) Change it to actually be a *Use* iterator rather than a *User* iterator. 3) Add an adaptor which is a User iterator that always looks through the Use to the User. 4) Wrap these in Value::use_iterator and Value::user_iterator typedefs. 5) Add the range adaptors as Value::uses() and Value::users(). 6) Update *all* of the callers to correctly distinguish between whether they wanted a use_iterator (and to explicitly dig out the User when needed), or a user_iterator which makes the Use itself totally opaque. Because #6 requires churning essentially everything that walked the Use-Def chains, I went ahead and added all of the range adaptors and switched them to range-based loops where appropriate. Also because the renaming requires at least churning every line of code, it didn't make any sense to split these up into multiple commits -- all of which would touch all of the same lies of code. The result is still not quite optimal. The Value::use_iterator is a nice regular iterator, but Value::user_iterator is an iterator over User*s rather than over the User objects themselves. As a consequence, it fits a bit awkwardly into the range-based world and it has the weird extra-dereferencing 'operator->' that so many of our iterators have. I think this could be fixed by providing something which transforms a range of T&s into a range of T*s, but that *can* be separated into another patch, and it isn't yet 100% clear whether this is the right move. However, this change gets us most of the benefit and cleans up a substantial amount of code around Use and User. =] git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203364 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-09 03:16:01 +00:00
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;
}