PassManagerBuilder.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
1//===- PassManagerBuilder.cpp - Build Standard Pass -----------------------===//
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// This file defines the PassManagerBuilder class, which is used to set up a
11// "standard" optimization sequence suitable for languages like C and C++.
12//
13//===----------------------------------------------------------------------===//
14
15
16#include "llvm/Transforms/IPO/PassManagerBuilder.h"
17#include "llvm-c/Transforms/PassManagerBuilder.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/Analysis/Passes.h"
20#include "llvm/IR/Verifier.h"
21#include "llvm/PassManager.h"
22#include "llvm/Support/CommandLine.h"
23#include "llvm/Support/ManagedStatic.h"
24#include "llvm/Target/TargetLibraryInfo.h"
25#include "llvm/Transforms/IPO.h"
26#include "llvm/Transforms/Scalar.h"
27#include "llvm/Transforms/Vectorize.h"
28
29using namespace llvm;
30
31static cl::opt<bool>
32RunLoopVectorization("vectorize-loops", cl::Hidden,
33                     cl::desc("Run the Loop vectorization passes"));
34
35static cl::opt<bool>
36RunSLPVectorization("vectorize-slp", cl::Hidden,
37                    cl::desc("Run the SLP vectorization passes"));
38
39static cl::opt<bool>
40RunBBVectorization("vectorize-slp-aggressive", cl::Hidden,
41                    cl::desc("Run the BB vectorization passes"));
42
43static cl::opt<bool>
44UseGVNAfterVectorization("use-gvn-after-vectorization",
45  cl::init(false), cl::Hidden,
46  cl::desc("Run GVN instead of Early CSE after vectorization passes"));
47
48static cl::opt<bool> UseNewSROA("use-new-sroa",
49  cl::init(true), cl::Hidden,
50  cl::desc("Enable the new, experimental SROA pass"));
51
52static cl::opt<bool>
53RunLoopRerolling("reroll-loops", cl::Hidden,
54                 cl::desc("Run the loop rerolling pass"));
55
56PassManagerBuilder::PassManagerBuilder() {
57    OptLevel = 2;
58    SizeLevel = 0;
59    LibraryInfo = 0;
60    Inliner = 0;
61    DisableUnitAtATime = false;
62    DisableUnrollLoops = false;
63    BBVectorize = RunBBVectorization;
64    SLPVectorize = RunSLPVectorization;
65    LoopVectorize = RunLoopVectorization;
66    RerollLoops = RunLoopRerolling;
67}
68
69PassManagerBuilder::~PassManagerBuilder() {
70  delete LibraryInfo;
71  delete Inliner;
72}
73
74/// Set of global extensions, automatically added as part of the standard set.
75static ManagedStatic<SmallVector<std::pair<PassManagerBuilder::ExtensionPointTy,
76   PassManagerBuilder::ExtensionFn>, 8> > GlobalExtensions;
77
78void PassManagerBuilder::addGlobalExtension(
79    PassManagerBuilder::ExtensionPointTy Ty,
80    PassManagerBuilder::ExtensionFn Fn) {
81  GlobalExtensions->push_back(std::make_pair(Ty, Fn));
82}
83
84void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
85  Extensions.push_back(std::make_pair(Ty, Fn));
86}
87
88void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy,
89                                           PassManagerBase &PM) const {
90  for (unsigned i = 0, e = GlobalExtensions->size(); i != e; ++i)
91    if ((*GlobalExtensions)[i].first == ETy)
92      (*GlobalExtensions)[i].second(*this, PM);
93  for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
94    if (Extensions[i].first == ETy)
95      Extensions[i].second(*this, PM);
96}
97
98void
99PassManagerBuilder::addInitialAliasAnalysisPasses(PassManagerBase &PM) const {
100  // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
101  // BasicAliasAnalysis wins if they disagree. This is intended to help
102  // support "obvious" type-punning idioms.
103  PM.add(createTypeBasedAliasAnalysisPass());
104  PM.add(createBasicAliasAnalysisPass());
105}
106
107void PassManagerBuilder::populateFunctionPassManager(FunctionPassManager &FPM) {
108  addExtensionsToPM(EP_EarlyAsPossible, FPM);
109
110  // Add LibraryInfo if we have some.
111  if (LibraryInfo) FPM.add(new TargetLibraryInfo(*LibraryInfo));
112
113  if (OptLevel == 0) return;
114
115  addInitialAliasAnalysisPasses(FPM);
116
117  FPM.add(createCFGSimplificationPass());
118  if (UseNewSROA)
119    FPM.add(createSROAPass());
120  else
121    FPM.add(createScalarReplAggregatesPass());
122  FPM.add(createEarlyCSEPass());
123  FPM.add(createLowerExpectIntrinsicPass());
124}
125
126void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
127  // If all optimizations are disabled, just run the always-inline pass.
128  if (OptLevel == 0) {
129    if (Inliner) {
130      MPM.add(Inliner);
131      Inliner = 0;
132    }
133
134    // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
135    // pass manager, but we don't want to add extensions into that pass manager.
136    // To prevent this we must insert a no-op module pass to reset the pass
137    // manager to get the same behavior as EP_OptimizerLast in non-O0 builds.
138    if (!GlobalExtensions->empty() || !Extensions.empty())
139      MPM.add(createBarrierNoopPass());
140
141    addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
142    return;
143  }
144
145  // Add LibraryInfo if we have some.
146  if (LibraryInfo) MPM.add(new TargetLibraryInfo(*LibraryInfo));
147
148  addInitialAliasAnalysisPasses(MPM);
149
150  if (!DisableUnitAtATime) {
151    addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
152
153    MPM.add(createGlobalOptimizerPass());     // Optimize out global vars
154
155    MPM.add(createIPSCCPPass());              // IP SCCP
156    MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
157
158    MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
159    MPM.add(createCFGSimplificationPass());   // Clean up after IPCP & DAE
160  }
161
162  // Start of CallGraph SCC passes.
163  if (!DisableUnitAtATime)
164    MPM.add(createPruneEHPass());             // Remove dead EH info
165  if (Inliner) {
166    MPM.add(Inliner);
167    Inliner = 0;
168  }
169  if (!DisableUnitAtATime)
170    MPM.add(createFunctionAttrsPass());       // Set readonly/readnone attrs
171  if (OptLevel > 2)
172    MPM.add(createArgumentPromotionPass());   // Scalarize uninlined fn args
173
174  // Start of function pass.
175  // Break up aggregate allocas, using SSAUpdater.
176  if (UseNewSROA)
177    MPM.add(createSROAPass(/*RequiresDomTree*/ false));
178  else
179    MPM.add(createScalarReplAggregatesPass(-1, false));
180  MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
181  MPM.add(createJumpThreadingPass());         // Thread jumps.
182  MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
183  MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
184  MPM.add(createInstructionCombiningPass());  // Combine silly seq's
185
186  MPM.add(createTailCallEliminationPass());   // Eliminate tail calls
187  MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
188  MPM.add(createReassociatePass());           // Reassociate expressions
189  MPM.add(createLoopRotatePass());            // Rotate Loop
190  MPM.add(createLICMPass());                  // Hoist loop invariants
191  MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3));
192  MPM.add(createInstructionCombiningPass());
193  MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
194  MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
195  MPM.add(createLoopDeletionPass());          // Delete dead loops
196
197  if (!DisableUnrollLoops)
198    MPM.add(createSimpleLoopUnrollPass());    // Unroll small loops
199  addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
200
201  if (OptLevel > 1)
202    MPM.add(createGVNPass());                 // Remove redundancies
203  MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
204  MPM.add(createSCCPPass());                  // Constant prop with SCCP
205
206  // Run instcombine after redundancy elimination to exploit opportunities
207  // opened up by them.
208  MPM.add(createInstructionCombiningPass());
209  MPM.add(createJumpThreadingPass());         // Thread jumps
210  MPM.add(createCorrelatedValuePropagationPass());
211  MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
212
213  addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
214
215  if (RerollLoops)
216    MPM.add(createLoopRerollPass());
217  if (SLPVectorize)
218    MPM.add(createSLPVectorizerPass());   // Vectorize parallel scalar chains.
219
220  if (BBVectorize) {
221    MPM.add(createBBVectorizePass());
222    MPM.add(createInstructionCombiningPass());
223    if (OptLevel > 1 && UseGVNAfterVectorization)
224      MPM.add(createGVNPass());           // Remove redundancies
225    else
226      MPM.add(createEarlyCSEPass());      // Catch trivial redundancies
227
228    // BBVectorize may have significantly shortened a loop body; unroll again.
229    if (!DisableUnrollLoops)
230      MPM.add(createLoopUnrollPass());
231  }
232
233  MPM.add(createAggressiveDCEPass());         // Delete dead instructions
234  MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
235  MPM.add(createInstructionCombiningPass());  // Clean up after everything.
236
237  // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
238  // pass manager that we are specifically trying to avoid. To prevent this
239  // we must insert a no-op module pass to reset the pass manager.
240  MPM.add(createBarrierNoopPass());
241  MPM.add(createLoopVectorizePass(DisableUnrollLoops, LoopVectorize));
242  // FIXME: Because of #pragma vectorize enable, the passes below are always
243  // inserted in the pipeline, even when the vectorizer doesn't run (ex. when
244  // on -O1 and no #pragma is found). Would be good to have these two passes
245  // as function calls, so that we can only pass them when the vectorizer
246  // changed the code.
247  MPM.add(createInstructionCombiningPass());
248  MPM.add(createCFGSimplificationPass());
249
250  if (!DisableUnrollLoops)
251    MPM.add(createLoopUnrollPass());    // Unroll small loops
252
253  if (!DisableUnitAtATime) {
254    // FIXME: We shouldn't bother with this anymore.
255    MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
256
257    // GlobalOpt already deletes dead functions and globals, at -O2 try a
258    // late pass of GlobalDCE.  It is capable of deleting dead cycles.
259    if (OptLevel > 1) {
260      MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
261      MPM.add(createConstantMergePass());     // Merge dup global constants
262    }
263  }
264  addExtensionsToPM(EP_OptimizerLast, MPM);
265}
266
267void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
268                                                bool Internalize,
269                                                bool RunInliner,
270                                                bool DisableGVNLoadPRE) {
271  // Provide AliasAnalysis services for optimizations.
272  addInitialAliasAnalysisPasses(PM);
273
274  // Now that composite has been compiled, scan through the module, looking
275  // for a main function.  If main is defined, mark all other functions
276  // internal.
277  if (Internalize)
278    PM.add(createInternalizePass("main"));
279
280  // Propagate constants at call sites into the functions they call.  This
281  // opens opportunities for globalopt (and inlining) by substituting function
282  // pointers passed as arguments to direct uses of functions.
283  PM.add(createIPSCCPPass());
284
285  // Now that we internalized some globals, see if we can hack on them!
286  PM.add(createGlobalOptimizerPass());
287
288  // Linking modules together can lead to duplicated global constants, only
289  // keep one copy of each constant.
290  PM.add(createConstantMergePass());
291
292  // Remove unused arguments from functions.
293  PM.add(createDeadArgEliminationPass());
294
295  // Reduce the code after globalopt and ipsccp.  Both can open up significant
296  // simplification opportunities, and both can propagate functions through
297  // function pointers.  When this happens, we often have to resolve varargs
298  // calls, etc, so let instcombine do this.
299  PM.add(createInstructionCombiningPass());
300
301  // Inline small functions
302  if (RunInliner)
303    PM.add(createFunctionInliningPass());
304
305  PM.add(createPruneEHPass());   // Remove dead EH info.
306
307  // Optimize globals again if we ran the inliner.
308  if (RunInliner)
309    PM.add(createGlobalOptimizerPass());
310  PM.add(createGlobalDCEPass()); // Remove dead functions.
311
312  // If we didn't decide to inline a function, check to see if we can
313  // transform it to pass arguments by value instead of by reference.
314  PM.add(createArgumentPromotionPass());
315
316  // The IPO passes may leave cruft around.  Clean up after them.
317  PM.add(createInstructionCombiningPass());
318  PM.add(createJumpThreadingPass());
319
320  // Break up allocas
321  if (UseNewSROA)
322    PM.add(createSROAPass());
323  else
324    PM.add(createScalarReplAggregatesPass());
325
326  // Run a few AA driven optimizations here and now, to cleanup the code.
327  PM.add(createFunctionAttrsPass()); // Add nocapture.
328  PM.add(createGlobalsModRefPass()); // IP alias analysis.
329
330  PM.add(createLICMPass());                 // Hoist loop invariants.
331  PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
332  PM.add(createMemCpyOptPass());            // Remove dead memcpys.
333
334  // Nuke dead stores.
335  PM.add(createDeadStoreEliminationPass());
336
337  // More loops are countable try to vectorize them.
338  PM.add(createLoopVectorizePass(true, true));
339
340  // Cleanup and simplify the code after the scalar optimizations.
341  PM.add(createInstructionCombiningPass());
342
343  PM.add(createJumpThreadingPass());
344
345  // Delete basic blocks, which optimization passes may have killed.
346  PM.add(createCFGSimplificationPass());
347
348  // Now that we have optimized the program, discard unreachable functions.
349  PM.add(createGlobalDCEPass());
350}
351
352inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) {
353    return reinterpret_cast<PassManagerBuilder*>(P);
354}
355
356inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) {
357  return reinterpret_cast<LLVMPassManagerBuilderRef>(P);
358}
359
360LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() {
361  PassManagerBuilder *PMB = new PassManagerBuilder();
362  return wrap(PMB);
363}
364
365void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
366  PassManagerBuilder *Builder = unwrap(PMB);
367  delete Builder;
368}
369
370void
371LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
372                                  unsigned OptLevel) {
373  PassManagerBuilder *Builder = unwrap(PMB);
374  Builder->OptLevel = OptLevel;
375}
376
377void
378LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
379                                   unsigned SizeLevel) {
380  PassManagerBuilder *Builder = unwrap(PMB);
381  Builder->SizeLevel = SizeLevel;
382}
383
384void
385LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
386                                            LLVMBool Value) {
387  PassManagerBuilder *Builder = unwrap(PMB);
388  Builder->DisableUnitAtATime = Value;
389}
390
391void
392LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
393                                            LLVMBool Value) {
394  PassManagerBuilder *Builder = unwrap(PMB);
395  Builder->DisableUnrollLoops = Value;
396}
397
398void
399LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
400                                                 LLVMBool Value) {
401  // NOTE: The simplify-libcalls pass has been removed.
402}
403
404void
405LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
406                                              unsigned Threshold) {
407  PassManagerBuilder *Builder = unwrap(PMB);
408  Builder->Inliner = createFunctionInliningPass(Threshold);
409}
410
411void
412LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
413                                                  LLVMPassManagerRef PM) {
414  PassManagerBuilder *Builder = unwrap(PMB);
415  FunctionPassManager *FPM = unwrap<FunctionPassManager>(PM);
416  Builder->populateFunctionPassManager(*FPM);
417}
418
419void
420LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
421                                                LLVMPassManagerRef PM) {
422  PassManagerBuilder *Builder = unwrap(PMB);
423  PassManagerBase *MPM = unwrap(PM);
424  Builder->populateModulePassManager(*MPM);
425}
426
427void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
428                                                  LLVMPassManagerRef PM,
429                                                  LLVMBool Internalize,
430                                                  LLVMBool RunInliner) {
431  PassManagerBuilder *Builder = unwrap(PMB);
432  PassManagerBase *LPM = unwrap(PM);
433  Builder->populateLTOPassManager(*LPM, Internalize != 0, RunInliner != 0);
434}
435