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//===-- NVPTXAsmPrinter.h - NVPTX LLVM assembly writer ----------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file contains a printer that converts from our internal representation
// of machine-dependent LLVM code to NVPTX assembly language.
#include "NVPTX.h"
#include "NVPTXSubtarget.h"
#include "NVPTXTargetMachine.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Value.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/PassAnalysisSupport.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include <algorithm>
#include <cassert>
#include <map>
#include <memory>
#include <string>
#include <vector>
// The ptx syntax and format is very different from that usually seem in a .s
// file,
// therefore we are not able to use the MCAsmStreamer interface here.
// We are handcrafting the output method here.
// A better approach is to clone the MCAsmStreamer to a MCPTXAsmStreamer
// (subclass of MCStreamer).
namespace llvm {
class MCOperand;
class LLVM_LIBRARY_VISIBILITY NVPTXAsmPrinter : public AsmPrinter {
class AggBuffer {
// Used to buffer the emitted string for initializing global
// aggregates.
// Normally an aggregate (array, vector or structure) is emitted
// as a u8[]. However, if one element/field of the aggregate
// is a non-NULL address, then the aggregate is emitted as u32[]
// or u64[].
// We first layout the aggregate in 'buffer' in bytes, except for
// those symbol addresses. For the i-th symbol address in the
//aggregate, its corresponding 4-byte or 8-byte elements in 'buffer'
// are filled with 0s. symbolPosInBuffer[i-1] records its position
// in 'buffer', and Symbols[i-1] records the Value*.
// Once we have this AggBuffer setup, we can choose how to print
// it out.
unsigned numSymbols; // number of symbol addresses
const unsigned size; // size of the buffer in bytes
std::vector<unsigned char> buffer; // the buffer
SmallVector<unsigned, 4> symbolPosInBuffer;
SmallVector<const Value *, 4> Symbols;
// SymbolsBeforeStripping[i] is the original form of Symbols[i] before
// stripping pointer casts, i.e.,
// Symbols[i] == SymbolsBeforeStripping[i]->stripPointerCasts().
// We need to keep these values because AggBuffer::print decides whether to
// emit a "generic()" cast for Symbols[i] depending on the address space of
// SymbolsBeforeStripping[i].
SmallVector<const Value *, 4> SymbolsBeforeStripping;
unsigned curpos;
raw_ostream &O;
NVPTXAsmPrinter &AP;
bool EmitGeneric;
AggBuffer(unsigned size, raw_ostream &O, NVPTXAsmPrinter &AP)
: size(size), buffer(size), O(O), AP(AP) {
curpos = 0;
numSymbols = 0;
EmitGeneric = AP.EmitGeneric;
unsigned addBytes(unsigned char *Ptr, int Num, int Bytes) {
assert((curpos + Num) <= size);
assert((curpos + Bytes) <= size);
for (int i = 0; i < Num; ++i) {
buffer[curpos] = Ptr[i];
for (int i = Num; i < Bytes; ++i) {
buffer[curpos] = 0;
return curpos;
unsigned addZeros(int Num) {
assert((curpos + Num) <= size);
for (int i = 0; i < Num; ++i) {
buffer[curpos] = 0;
return curpos;
void addSymbol(const Value *GVar, const Value *GVarBeforeStripping) {
void print() {
if (numSymbols == 0) {
// print out in bytes
for (unsigned i = 0; i < size; i++) {
if (i)
O << ", ";
O << (unsigned int) buffer[i];
} else {
// print out in 4-bytes or 8-bytes
unsigned int pos = 0;
unsigned int nSym = 0;
unsigned int nextSymbolPos = symbolPosInBuffer[nSym];
unsigned int nBytes = 4;
if (static_cast<const NVPTXTargetMachine &>(AP.TM).is64Bit())
nBytes = 8;
for (pos = 0; pos < size; pos += nBytes) {
if (pos)
O << ", ";
if (pos == nextSymbolPos) {
const Value *v = Symbols[nSym];
const Value *v0 = SymbolsBeforeStripping[nSym];
if (const GlobalValue *GVar = dyn_cast<GlobalValue>(v)) {
MCSymbol *Name = AP.getSymbol(GVar);
PointerType *PTy = dyn_cast<PointerType>(v0->getType());
bool IsNonGenericPointer = false; // Is v0 a non-generic pointer?
if (PTy && PTy->getAddressSpace() != 0) {
IsNonGenericPointer = true;
if (EmitGeneric && !isa<Function>(v) && !IsNonGenericPointer) {
O << "generic(";
Name->print(O, AP.MAI);
O << ")";
} else {
Name->print(O, AP.MAI);
} else if (const ConstantExpr *CExpr = dyn_cast<ConstantExpr>(v0)) {
const MCExpr *Expr =
AP.lowerConstantForGV(cast<Constant>(CExpr), false);
AP.printMCExpr(*Expr, O);
} else
llvm_unreachable("symbol type unknown");
if (nSym >= numSymbols)
nextSymbolPos = size + 1;
nextSymbolPos = symbolPosInBuffer[nSym];
} else if (nBytes == 4)
O << *(unsigned int *)(&buffer[pos]);
O << *(unsigned long long *)(&buffer[pos]);
friend class AggBuffer;
StringRef getPassName() const override { return "NVPTX Assembly Printer"; }
const Function *F;
std::string CurrentFnName;
void EmitBasicBlockStart(const MachineBasicBlock &MBB) const override;
void EmitFunctionEntryLabel() override;
void EmitFunctionBodyStart() override;
void EmitFunctionBodyEnd() override;
void emitImplicitDef(const MachineInstr *MI) const override;
void EmitInstruction(const MachineInstr *) override;
void lowerToMCInst(const MachineInstr *MI, MCInst &OutMI);
bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp);
MCOperand GetSymbolRef(const MCSymbol *Symbol);
unsigned encodeVirtualRegister(unsigned Reg);
void printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
const char *Modifier = nullptr);
void printModuleLevelGV(const GlobalVariable *GVar, raw_ostream &O,
bool = false);
void printParamName(Function::const_arg_iterator I, int paramIndex,
raw_ostream &O);
void emitGlobals(const Module &M);
void emitHeader(Module &M, raw_ostream &O, const NVPTXSubtarget &STI);
void emitKernelFunctionDirectives(const Function &F, raw_ostream &O) const;
void emitVirtualRegister(unsigned int vr, raw_ostream &);
void emitFunctionParamList(const Function *, raw_ostream &O);
void emitFunctionParamList(const MachineFunction &MF, raw_ostream &O);
void setAndEmitFunctionVirtualRegisters(const MachineFunction &MF);
void printReturnValStr(const Function *, raw_ostream &O);
void printReturnValStr(const MachineFunction &MF, raw_ostream &O);
bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &) override;
void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &) override;
const MCExpr *lowerConstantForGV(const Constant *CV, bool ProcessingGeneric);
void printMCExpr(const MCExpr &Expr, raw_ostream &OS);
bool doInitialization(Module &M) override;
bool doFinalization(Module &M) override;
bool GlobalsEmitted;
// This is specific per MachineFunction.
const MachineRegisterInfo *MRI;
// The contents are specific for each
// MachineFunction. But the size of the
// array is not.
typedef DenseMap<unsigned, unsigned> VRegMap;
typedef DenseMap<const TargetRegisterClass *, VRegMap> VRegRCMap;
VRegRCMap VRegMapping;
// List of variables demoted to a function scope.
std::map<const Function *, std::vector<const GlobalVariable *>> localDecls;
void emitPTXGlobalVariable(const GlobalVariable *GVar, raw_ostream &O);
void emitPTXAddressSpace(unsigned int AddressSpace, raw_ostream &O) const;
std::string getPTXFundamentalTypeStr(Type *Ty, bool = true) const;
void printScalarConstant(const Constant *CPV, raw_ostream &O);
void printFPConstant(const ConstantFP *Fp, raw_ostream &O);
void bufferLEByte(const Constant *CPV, int Bytes, AggBuffer *aggBuffer);
void bufferAggregateConstant(const Constant *CV, AggBuffer *aggBuffer);
void emitLinkageDirective(const GlobalValue *V, raw_ostream &O);
void emitDeclarations(const Module &, raw_ostream &O);
void emitDeclaration(const Function *, raw_ostream &O);
void emitDemotedVars(const Function *, raw_ostream &);
bool lowerImageHandleOperand(const MachineInstr *MI, unsigned OpNo,
MCOperand &MCOp);
void lowerImageHandleSymbol(unsigned Index, MCOperand &MCOp);
bool isLoopHeaderOfNoUnroll(const MachineBasicBlock &MBB) const;
// Used to control the need to emit .generic() in the initializer of
// module scope variables.
// Although ptx supports the hybrid mode like the following,
// .global .u32 a;
// .global .u32 b;
// .global .u32 addr[] = {a, generic(b)}
// we have difficulty representing the difference in the NVVM IR.
// Since the address value should always be generic in CUDA C and always
// be specific in OpenCL, we use this simple control here.
bool EmitGeneric;
NVPTXAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
: AsmPrinter(TM, std::move(Streamer)),
EmitGeneric(static_cast<NVPTXTargetMachine &>(TM).getDrvInterface() ==
bool runOnMachineFunction(MachineFunction &F) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
std::string getVirtualRegisterName(unsigned) const;
const MCSymbol *getFunctionFrameSymbol() const override;
} // end namespace llvm