1 //===-- NVPTXTargetMachine.cpp - Define TargetMachine for NVPTX -----------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Top-level implementation for the NVPTX target.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "NVPTXTargetMachine.h"
15 #include "MCTargetDesc/NVPTXMCAsmInfo.h"
16 #include "NVPTX.h"
17 #include "NVPTXAllocaHoisting.h"
18 #include "NVPTXLowerAggrCopies.h"
19 #include "NVPTXTargetObjectFile.h"
20 #include "NVPTXTargetTransformInfo.h"
21 #include "llvm/Analysis/Passes.h"
22 #include "llvm/CodeGen/AsmPrinter.h"
23 #include "llvm/CodeGen/MachineFunctionAnalysis.h"
24 #include "llvm/CodeGen/MachineModuleInfo.h"
25 #include "llvm/CodeGen/Passes.h"
26 #include "llvm/IR/DataLayout.h"
27 #include "llvm/IR/IRPrintingPasses.h"
28 #include "llvm/IR/LegacyPassManager.h"
29 #include "llvm/IR/Verifier.h"
30 #include "llvm/MC/MCAsmInfo.h"
31 #include "llvm/MC/MCInstrInfo.h"
32 #include "llvm/MC/MCStreamer.h"
33 #include "llvm/MC/MCSubtargetInfo.h"
34 #include "llvm/Support/CommandLine.h"
35 #include "llvm/Support/Debug.h"
36 #include "llvm/Support/FormattedStream.h"
37 #include "llvm/Support/TargetRegistry.h"
38 #include "llvm/Support/raw_ostream.h"
39 #include "llvm/Target/TargetInstrInfo.h"
40 #include "llvm/Target/TargetLowering.h"
41 #include "llvm/Target/TargetLoweringObjectFile.h"
42 #include "llvm/Target/TargetMachine.h"
43 #include "llvm/Target/TargetOptions.h"
44 #include "llvm/Target/TargetRegisterInfo.h"
45 #include "llvm/Target/TargetSubtargetInfo.h"
46 #include "llvm/Transforms/Scalar.h"
47
48 using namespace llvm;
49
50 namespace llvm {
51 void initializeNVVMReflectPass(PassRegistry&);
52 void initializeGenericToNVVMPass(PassRegistry&);
53 void initializeNVPTXAllocaHoistingPass(PassRegistry &);
54 void initializeNVPTXAssignValidGlobalNamesPass(PassRegistry&);
55 void initializeNVPTXFavorNonGenericAddrSpacesPass(PassRegistry &);
56 void initializeNVPTXLowerAggrCopiesPass(PassRegistry &);
57 void initializeNVPTXLowerKernelArgsPass(PassRegistry &);
58 void initializeNVPTXLowerAllocaPass(PassRegistry &);
59 }
60
LLVMInitializeNVPTXTarget()61 extern "C" void LLVMInitializeNVPTXTarget() {
62 // Register the target.
63 RegisterTargetMachine<NVPTXTargetMachine32> X(TheNVPTXTarget32);
64 RegisterTargetMachine<NVPTXTargetMachine64> Y(TheNVPTXTarget64);
65
66 // FIXME: This pass is really intended to be invoked during IR optimization,
67 // but it's very NVPTX-specific.
68 PassRegistry &PR = *PassRegistry::getPassRegistry();
69 initializeNVVMReflectPass(PR);
70 initializeGenericToNVVMPass(PR);
71 initializeNVPTXAllocaHoistingPass(PR);
72 initializeNVPTXAssignValidGlobalNamesPass(PR);
73 initializeNVPTXFavorNonGenericAddrSpacesPass(PR);
74 initializeNVPTXLowerKernelArgsPass(PR);
75 initializeNVPTXLowerAllocaPass(PR);
76 initializeNVPTXLowerAggrCopiesPass(PR);
77 }
78
computeDataLayout(bool is64Bit)79 static std::string computeDataLayout(bool is64Bit) {
80 std::string Ret = "e";
81
82 if (!is64Bit)
83 Ret += "-p:32:32";
84
85 Ret += "-i64:64-v16:16-v32:32-n16:32:64";
86
87 return Ret;
88 }
89
NVPTXTargetMachine(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,const TargetOptions & Options,Reloc::Model RM,CodeModel::Model CM,CodeGenOpt::Level OL,bool is64bit)90 NVPTXTargetMachine::NVPTXTargetMachine(const Target &T, const Triple &TT,
91 StringRef CPU, StringRef FS,
92 const TargetOptions &Options,
93 Reloc::Model RM, CodeModel::Model CM,
94 CodeGenOpt::Level OL, bool is64bit)
95 : LLVMTargetMachine(T, computeDataLayout(is64bit), TT, CPU, FS, Options, RM,
96 CM, OL),
97 is64bit(is64bit), TLOF(make_unique<NVPTXTargetObjectFile>()),
98 Subtarget(TT, CPU, FS, *this) {
99 if (TT.getOS() == Triple::NVCL)
100 drvInterface = NVPTX::NVCL;
101 else
102 drvInterface = NVPTX::CUDA;
103 initAsmInfo();
104 }
105
~NVPTXTargetMachine()106 NVPTXTargetMachine::~NVPTXTargetMachine() {}
107
anchor()108 void NVPTXTargetMachine32::anchor() {}
109
NVPTXTargetMachine32(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,const TargetOptions & Options,Reloc::Model RM,CodeModel::Model CM,CodeGenOpt::Level OL)110 NVPTXTargetMachine32::NVPTXTargetMachine32(const Target &T, const Triple &TT,
111 StringRef CPU, StringRef FS,
112 const TargetOptions &Options,
113 Reloc::Model RM, CodeModel::Model CM,
114 CodeGenOpt::Level OL)
115 : NVPTXTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, false) {}
116
anchor()117 void NVPTXTargetMachine64::anchor() {}
118
NVPTXTargetMachine64(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,const TargetOptions & Options,Reloc::Model RM,CodeModel::Model CM,CodeGenOpt::Level OL)119 NVPTXTargetMachine64::NVPTXTargetMachine64(const Target &T, const Triple &TT,
120 StringRef CPU, StringRef FS,
121 const TargetOptions &Options,
122 Reloc::Model RM, CodeModel::Model CM,
123 CodeGenOpt::Level OL)
124 : NVPTXTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, true) {}
125
126 namespace {
127 class NVPTXPassConfig : public TargetPassConfig {
128 public:
NVPTXPassConfig(NVPTXTargetMachine * TM,PassManagerBase & PM)129 NVPTXPassConfig(NVPTXTargetMachine *TM, PassManagerBase &PM)
130 : TargetPassConfig(TM, PM) {}
131
getNVPTXTargetMachine() const132 NVPTXTargetMachine &getNVPTXTargetMachine() const {
133 return getTM<NVPTXTargetMachine>();
134 }
135
136 void addIRPasses() override;
137 bool addInstSelector() override;
138 void addPostRegAlloc() override;
139 void addMachineSSAOptimization() override;
140
141 FunctionPass *createTargetRegisterAllocator(bool) override;
142 void addFastRegAlloc(FunctionPass *RegAllocPass) override;
143 void addOptimizedRegAlloc(FunctionPass *RegAllocPass) override;
144
145 private:
146 // if the opt level is aggressive, add GVN; otherwise, add EarlyCSE.
147 void addEarlyCSEOrGVNPass();
148 };
149 } // end anonymous namespace
150
createPassConfig(PassManagerBase & PM)151 TargetPassConfig *NVPTXTargetMachine::createPassConfig(PassManagerBase &PM) {
152 NVPTXPassConfig *PassConfig = new NVPTXPassConfig(this, PM);
153 return PassConfig;
154 }
155
getTargetIRAnalysis()156 TargetIRAnalysis NVPTXTargetMachine::getTargetIRAnalysis() {
157 return TargetIRAnalysis([this](const Function &F) {
158 return TargetTransformInfo(NVPTXTTIImpl(this, F));
159 });
160 }
161
addEarlyCSEOrGVNPass()162 void NVPTXPassConfig::addEarlyCSEOrGVNPass() {
163 if (getOptLevel() == CodeGenOpt::Aggressive)
164 addPass(createGVNPass());
165 else
166 addPass(createEarlyCSEPass());
167 }
168
addIRPasses()169 void NVPTXPassConfig::addIRPasses() {
170 // The following passes are known to not play well with virtual regs hanging
171 // around after register allocation (which in our case, is *all* registers).
172 // We explicitly disable them here. We do, however, need some functionality
173 // of the PrologEpilogCodeInserter pass, so we emulate that behavior in the
174 // NVPTXPrologEpilog pass (see NVPTXPrologEpilogPass.cpp).
175 disablePass(&PrologEpilogCodeInserterID);
176 disablePass(&MachineCopyPropagationID);
177 disablePass(&TailDuplicateID);
178
179 addPass(createNVVMReflectPass());
180 addPass(createNVPTXImageOptimizerPass());
181 addPass(createNVPTXAssignValidGlobalNamesPass());
182 addPass(createGenericToNVVMPass());
183
184 // === Propagate special address spaces ===
185 addPass(createNVPTXLowerKernelArgsPass(&getNVPTXTargetMachine()));
186 // NVPTXLowerKernelArgs emits alloca for byval parameters which can often
187 // be eliminated by SROA.
188 addPass(createSROAPass());
189 addPass(createNVPTXLowerAllocaPass());
190 addPass(createNVPTXFavorNonGenericAddrSpacesPass());
191 // FavorNonGenericAddrSpaces shortcuts unnecessary addrspacecasts, and leave
192 // them unused. We could remove dead code in an ad-hoc manner, but that
193 // requires manual work and might be error-prone.
194 addPass(createDeadCodeEliminationPass());
195
196 // === Straight-line scalar optimizations ===
197 addPass(createSeparateConstOffsetFromGEPPass());
198 addPass(createSpeculativeExecutionPass());
199 // ReassociateGEPs exposes more opportunites for SLSR. See
200 // the example in reassociate-geps-and-slsr.ll.
201 addPass(createStraightLineStrengthReducePass());
202 // SeparateConstOffsetFromGEP and SLSR creates common expressions which GVN or
203 // EarlyCSE can reuse. GVN generates significantly better code than EarlyCSE
204 // for some of our benchmarks.
205 addEarlyCSEOrGVNPass();
206 // Run NaryReassociate after EarlyCSE/GVN to be more effective.
207 addPass(createNaryReassociatePass());
208 // NaryReassociate on GEPs creates redundant common expressions, so run
209 // EarlyCSE after it.
210 addPass(createEarlyCSEPass());
211
212 // === LSR and other generic IR passes ===
213 TargetPassConfig::addIRPasses();
214 // EarlyCSE is not always strong enough to clean up what LSR produces. For
215 // example, GVN can combine
216 //
217 // %0 = add %a, %b
218 // %1 = add %b, %a
219 //
220 // and
221 //
222 // %0 = shl nsw %a, 2
223 // %1 = shl %a, 2
224 //
225 // but EarlyCSE can do neither of them.
226 addEarlyCSEOrGVNPass();
227 }
228
addInstSelector()229 bool NVPTXPassConfig::addInstSelector() {
230 const NVPTXSubtarget &ST = *getTM<NVPTXTargetMachine>().getSubtargetImpl();
231
232 addPass(createLowerAggrCopies());
233 addPass(createAllocaHoisting());
234 addPass(createNVPTXISelDag(getNVPTXTargetMachine(), getOptLevel()));
235
236 if (!ST.hasImageHandles())
237 addPass(createNVPTXReplaceImageHandlesPass());
238
239 return false;
240 }
241
addPostRegAlloc()242 void NVPTXPassConfig::addPostRegAlloc() {
243 addPass(createNVPTXPrologEpilogPass(), false);
244 // NVPTXPrologEpilogPass calculates frame object offset and replace frame
245 // index with VRFrame register. NVPTXPeephole need to be run after that and
246 // will replace VRFrame with VRFrameLocal when possible.
247 addPass(createNVPTXPeephole());
248 }
249
createTargetRegisterAllocator(bool)250 FunctionPass *NVPTXPassConfig::createTargetRegisterAllocator(bool) {
251 return nullptr; // No reg alloc
252 }
253
addFastRegAlloc(FunctionPass * RegAllocPass)254 void NVPTXPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
255 assert(!RegAllocPass && "NVPTX uses no regalloc!");
256 addPass(&PHIEliminationID);
257 addPass(&TwoAddressInstructionPassID);
258 }
259
addOptimizedRegAlloc(FunctionPass * RegAllocPass)260 void NVPTXPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
261 assert(!RegAllocPass && "NVPTX uses no regalloc!");
262
263 addPass(&ProcessImplicitDefsID);
264 addPass(&LiveVariablesID);
265 addPass(&MachineLoopInfoID);
266 addPass(&PHIEliminationID);
267
268 addPass(&TwoAddressInstructionPassID);
269 addPass(&RegisterCoalescerID);
270
271 // PreRA instruction scheduling.
272 if (addPass(&MachineSchedulerID))
273 printAndVerify("After Machine Scheduling");
274
275
276 addPass(&StackSlotColoringID);
277
278 // FIXME: Needs physical registers
279 //addPass(&PostRAMachineLICMID);
280
281 printAndVerify("After StackSlotColoring");
282 }
283
addMachineSSAOptimization()284 void NVPTXPassConfig::addMachineSSAOptimization() {
285 // Pre-ra tail duplication.
286 if (addPass(&EarlyTailDuplicateID))
287 printAndVerify("After Pre-RegAlloc TailDuplicate");
288
289 // Optimize PHIs before DCE: removing dead PHI cycles may make more
290 // instructions dead.
291 addPass(&OptimizePHIsID);
292
293 // This pass merges large allocas. StackSlotColoring is a different pass
294 // which merges spill slots.
295 addPass(&StackColoringID);
296
297 // If the target requests it, assign local variables to stack slots relative
298 // to one another and simplify frame index references where possible.
299 addPass(&LocalStackSlotAllocationID);
300
301 // With optimization, dead code should already be eliminated. However
302 // there is one known exception: lowered code for arguments that are only
303 // used by tail calls, where the tail calls reuse the incoming stack
304 // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
305 addPass(&DeadMachineInstructionElimID);
306 printAndVerify("After codegen DCE pass");
307
308 // Allow targets to insert passes that improve instruction level parallelism,
309 // like if-conversion. Such passes will typically need dominator trees and
310 // loop info, just like LICM and CSE below.
311 if (addILPOpts())
312 printAndVerify("After ILP optimizations");
313
314 addPass(&MachineLICMID);
315 addPass(&MachineCSEID);
316
317 addPass(&MachineSinkingID);
318 printAndVerify("After Machine LICM, CSE and Sinking passes");
319
320 addPass(&PeepholeOptimizerID);
321 printAndVerify("After codegen peephole optimization pass");
322 }
323