PassManagerBuilder.cpp revision cd81d94322a39503e4a3e87b6ee03d4fcb3465fb 
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
56static cl::opt<bool> RunLoadCombine("combine-loads", cl::init(false),
57                                    cl::Hidden,
58                                    cl::desc("Run the load combining pass"));
59
60PassManagerBuilder::PassManagerBuilder() {
61    OptLevel = 2;
62    SizeLevel = 0;
63    LibraryInfo = nullptr;
64    Inliner = nullptr;
65    DisableTailCalls = false;
66    DisableUnitAtATime = false;
67    DisableUnrollLoops = false;
68    BBVectorize = RunBBVectorization;
69    SLPVectorize = RunSLPVectorization;
70    LoopVectorize = RunLoopVectorization;
71    RerollLoops = RunLoopRerolling;
72    LoadCombine = RunLoadCombine;
73}
74
75PassManagerBuilder::~PassManagerBuilder() {
76  delete LibraryInfo;
77  delete Inliner;
78}
79
80/// Set of global extensions, automatically added as part of the standard set.
81static ManagedStatic<SmallVector<std::pair<PassManagerBuilder::ExtensionPointTy,
82   PassManagerBuilder::ExtensionFn>, 8> > GlobalExtensions;
83
84void PassManagerBuilder::addGlobalExtension(
85    PassManagerBuilder::ExtensionPointTy Ty,
86    PassManagerBuilder::ExtensionFn Fn) {
87  GlobalExtensions->push_back(std::make_pair(Ty, Fn));
88}
89
90void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
91  Extensions.push_back(std::make_pair(Ty, Fn));
92}
93
94void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy,
95                                           PassManagerBase &PM) const {
96  for (unsigned i = 0, e = GlobalExtensions->size(); i != e; ++i)
97    if ((*GlobalExtensions)[i].first == ETy)
98      (*GlobalExtensions)[i].second(*this, PM);
99  for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
100    if (Extensions[i].first == ETy)
101      Extensions[i].second(*this, PM);
102}
103
104void
105PassManagerBuilder::addInitialAliasAnalysisPasses(PassManagerBase &PM) const {
106  // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
107  // BasicAliasAnalysis wins if they disagree. This is intended to help
108  // support "obvious" type-punning idioms.
109  PM.add(createTypeBasedAliasAnalysisPass());
110  PM.add(createBasicAliasAnalysisPass());
111}
112
113void PassManagerBuilder::populateFunctionPassManager(FunctionPassManager &FPM) {
114  addExtensionsToPM(EP_EarlyAsPossible, FPM);
115
116  // Add LibraryInfo if we have some.
117  if (LibraryInfo) FPM.add(new TargetLibraryInfo(*LibraryInfo));
118
119  if (OptLevel == 0) return;
120
121  addInitialAliasAnalysisPasses(FPM);
122
123  FPM.add(createCFGSimplificationPass());
124  if (UseNewSROA)
125    FPM.add(createSROAPass());
126  else
127    FPM.add(createScalarReplAggregatesPass());
128  FPM.add(createEarlyCSEPass());
129  FPM.add(createLowerExpectIntrinsicPass());
130}
131
132void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
133  // If all optimizations are disabled, just run the always-inline pass.
134  if (OptLevel == 0) {
135    if (Inliner) {
136      MPM.add(Inliner);
137      Inliner = nullptr;
138    }
139
140    // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
141    // pass manager, but we don't want to add extensions into that pass manager.
142    // To prevent this we must insert a no-op module pass to reset the pass
143    // manager to get the same behavior as EP_OptimizerLast in non-O0 builds.
144    if (!GlobalExtensions->empty() || !Extensions.empty())
145      MPM.add(createBarrierNoopPass());
146
147    addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
148    return;
149  }
150
151  // Add LibraryInfo if we have some.
152  if (LibraryInfo) MPM.add(new TargetLibraryInfo(*LibraryInfo));
153
154  addInitialAliasAnalysisPasses(MPM);
155
156  if (!DisableUnitAtATime) {
157    addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
158
159    MPM.add(createIPSCCPPass());              // IP SCCP
160    MPM.add(createGlobalOptimizerPass());     // Optimize out global vars
161
162    MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
163
164    MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
165    addExtensionsToPM(EP_Peephole, MPM);
166    MPM.add(createCFGSimplificationPass());   // Clean up after IPCP & DAE
167  }
168
169  // Start of CallGraph SCC passes.
170  if (!DisableUnitAtATime)
171    MPM.add(createPruneEHPass());             // Remove dead EH info
172  if (Inliner) {
173    MPM.add(Inliner);
174    Inliner = nullptr;
175  }
176  if (!DisableUnitAtATime)
177    MPM.add(createFunctionAttrsPass());       // Set readonly/readnone attrs
178  if (OptLevel > 2)
179    MPM.add(createArgumentPromotionPass());   // Scalarize uninlined fn args
180
181  // Start of function pass.
182  // Break up aggregate allocas, using SSAUpdater.
183  if (UseNewSROA)
184    MPM.add(createSROAPass(/*RequiresDomTree*/ false));
185  else
186    MPM.add(createScalarReplAggregatesPass(-1, false));
187  MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
188  MPM.add(createJumpThreadingPass());         // Thread jumps.
189  MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
190  MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
191  MPM.add(createInstructionCombiningPass());  // Combine silly seq's
192  addExtensionsToPM(EP_Peephole, MPM);
193
194  if (!DisableTailCalls)
195    MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
196  MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
197  MPM.add(createReassociatePass());           // Reassociate expressions
198  MPM.add(createLoopRotatePass());            // Rotate Loop
199  MPM.add(createLICMPass());                  // Hoist loop invariants
200  MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3));
201  MPM.add(createInstructionCombiningPass());
202  MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
203  MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
204  MPM.add(createLoopDeletionPass());          // Delete dead loops
205
206  if (!DisableUnrollLoops)
207    MPM.add(createSimpleLoopUnrollPass());    // Unroll small loops
208  addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
209
210  if (OptLevel > 1)
211    MPM.add(createGVNPass());                 // Remove redundancies
212  MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
213  MPM.add(createSCCPPass());                  // Constant prop with SCCP
214
215  // Run instcombine after redundancy elimination to exploit opportunities
216  // opened up by them.
217  MPM.add(createInstructionCombiningPass());
218  addExtensionsToPM(EP_Peephole, MPM);
219  MPM.add(createJumpThreadingPass());         // Thread jumps
220  MPM.add(createCorrelatedValuePropagationPass());
221  MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
222
223  addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
224
225  if (RerollLoops)
226    MPM.add(createLoopRerollPass());
227  if (SLPVectorize)
228    MPM.add(createSLPVectorizerPass());   // Vectorize parallel scalar chains.
229
230  if (BBVectorize) {
231    MPM.add(createBBVectorizePass());
232    MPM.add(createInstructionCombiningPass());
233    addExtensionsToPM(EP_Peephole, MPM);
234    if (OptLevel > 1 && UseGVNAfterVectorization)
235      MPM.add(createGVNPass());           // Remove redundancies
236    else
237      MPM.add(createEarlyCSEPass());      // Catch trivial redundancies
238
239    // BBVectorize may have significantly shortened a loop body; unroll again.
240    if (!DisableUnrollLoops)
241      MPM.add(createLoopUnrollPass());
242  }
243
244  if (LoadCombine)
245    MPM.add(createLoadCombinePass());
246
247  MPM.add(createAggressiveDCEPass());         // Delete dead instructions
248  MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
249  MPM.add(createInstructionCombiningPass());  // Clean up after everything.
250  addExtensionsToPM(EP_Peephole, MPM);
251
252  // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
253  // pass manager that we are specifically trying to avoid. To prevent this
254  // we must insert a no-op module pass to reset the pass manager.
255  MPM.add(createBarrierNoopPass());
256  MPM.add(createLoopVectorizePass(DisableUnrollLoops, LoopVectorize));
257  // FIXME: Because of #pragma vectorize enable, the passes below are always
258  // inserted in the pipeline, even when the vectorizer doesn't run (ex. when
259  // on -O1 and no #pragma is found). Would be good to have these two passes
260  // as function calls, so that we can only pass them when the vectorizer
261  // changed the code.
262  MPM.add(createInstructionCombiningPass());
263  addExtensionsToPM(EP_Peephole, MPM);
264  MPM.add(createCFGSimplificationPass());
265
266  if (!DisableUnrollLoops)
267    MPM.add(createLoopUnrollPass());    // Unroll small loops
268
269  if (!DisableUnitAtATime) {
270    // FIXME: We shouldn't bother with this anymore.
271    MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
272
273    // GlobalOpt already deletes dead functions and globals, at -O2 try a
274    // late pass of GlobalDCE.  It is capable of deleting dead cycles.
275    if (OptLevel > 1) {
276      MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
277      MPM.add(createConstantMergePass());     // Merge dup global constants
278    }
279  }
280  addExtensionsToPM(EP_OptimizerLast, MPM);
281}
282
283void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
284                                                bool Internalize,
285                                                bool RunInliner,
286                                                bool DisableGVNLoadPRE) {
287  // Provide AliasAnalysis services for optimizations.
288  addInitialAliasAnalysisPasses(PM);
289
290  // Now that composite has been compiled, scan through the module, looking
291  // for a main function.  If main is defined, mark all other functions
292  // internal.
293  if (Internalize)
294    PM.add(createInternalizePass("main"));
295
296  // Propagate constants at call sites into the functions they call.  This
297  // opens opportunities for globalopt (and inlining) by substituting function
298  // pointers passed as arguments to direct uses of functions.
299  PM.add(createIPSCCPPass());
300
301  // Now that we internalized some globals, see if we can hack on them!
302  PM.add(createGlobalOptimizerPass());
303
304  // Linking modules together can lead to duplicated global constants, only
305  // keep one copy of each constant.
306  PM.add(createConstantMergePass());
307
308  // Remove unused arguments from functions.
309  PM.add(createDeadArgEliminationPass());
310
311  // Reduce the code after globalopt and ipsccp.  Both can open up significant
312  // simplification opportunities, and both can propagate functions through
313  // function pointers.  When this happens, we often have to resolve varargs
314  // calls, etc, so let instcombine do this.
315  PM.add(createInstructionCombiningPass());
316  addExtensionsToPM(EP_Peephole, PM);
317
318  // Inline small functions
319  if (RunInliner)
320    PM.add(createFunctionInliningPass());
321
322  PM.add(createPruneEHPass());   // Remove dead EH info.
323
324  // Optimize globals again if we ran the inliner.
325  if (RunInliner)
326    PM.add(createGlobalOptimizerPass());
327  PM.add(createGlobalDCEPass()); // Remove dead functions.
328
329  // If we didn't decide to inline a function, check to see if we can
330  // transform it to pass arguments by value instead of by reference.
331  PM.add(createArgumentPromotionPass());
332
333  // The IPO passes may leave cruft around.  Clean up after them.
334  PM.add(createInstructionCombiningPass());
335  addExtensionsToPM(EP_Peephole, PM);
336  PM.add(createJumpThreadingPass());
337
338  // Break up allocas
339  if (UseNewSROA)
340    PM.add(createSROAPass());
341  else
342    PM.add(createScalarReplAggregatesPass());
343
344  // Run a few AA driven optimizations here and now, to cleanup the code.
345  PM.add(createFunctionAttrsPass()); // Add nocapture.
346  PM.add(createGlobalsModRefPass()); // IP alias analysis.
347
348  PM.add(createLICMPass());                 // Hoist loop invariants.
349  PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
350  PM.add(createMemCpyOptPass());            // Remove dead memcpys.
351
352  // Nuke dead stores.
353  PM.add(createDeadStoreEliminationPass());
354
355  // More loops are countable; try to optimize them.
356  PM.add(createIndVarSimplifyPass());
357  PM.add(createLoopDeletionPass());
358  PM.add(createLoopVectorizePass(true, true));
359
360  // More scalar chains could be vectorized due to more alias information
361  PM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains.
362
363  if (LoadCombine)
364    PM.add(createLoadCombinePass());
365
366  // Cleanup and simplify the code after the scalar optimizations.
367  PM.add(createInstructionCombiningPass());
368  addExtensionsToPM(EP_Peephole, PM);
369
370  PM.add(createJumpThreadingPass());
371
372  // Delete basic blocks, which optimization passes may have killed.
373  PM.add(createCFGSimplificationPass());
374
375  // Now that we have optimized the program, discard unreachable functions.
376  PM.add(createGlobalDCEPass());
377}
378
379inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) {
380    return reinterpret_cast<PassManagerBuilder*>(P);
381}
382
383inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) {
384  return reinterpret_cast<LLVMPassManagerBuilderRef>(P);
385}
386
387LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() {
388  PassManagerBuilder *PMB = new PassManagerBuilder();
389  return wrap(PMB);
390}
391
392void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
393  PassManagerBuilder *Builder = unwrap(PMB);
394  delete Builder;
395}
396
397void
398LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
399                                  unsigned OptLevel) {
400  PassManagerBuilder *Builder = unwrap(PMB);
401  Builder->OptLevel = OptLevel;
402}
403
404void
405LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
406                                   unsigned SizeLevel) {
407  PassManagerBuilder *Builder = unwrap(PMB);
408  Builder->SizeLevel = SizeLevel;
409}
410
411void
412LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
413                                            LLVMBool Value) {
414  PassManagerBuilder *Builder = unwrap(PMB);
415  Builder->DisableUnitAtATime = Value;
416}
417
418void
419LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
420                                            LLVMBool Value) {
421  PassManagerBuilder *Builder = unwrap(PMB);
422  Builder->DisableUnrollLoops = Value;
423}
424
425void
426LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
427                                                 LLVMBool Value) {
428  // NOTE: The simplify-libcalls pass has been removed.
429}
430
431void
432LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
433                                              unsigned Threshold) {
434  PassManagerBuilder *Builder = unwrap(PMB);
435  Builder->Inliner = createFunctionInliningPass(Threshold);
436}
437
438void
439LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
440                                                  LLVMPassManagerRef PM) {
441  PassManagerBuilder *Builder = unwrap(PMB);
442  FunctionPassManager *FPM = unwrap<FunctionPassManager>(PM);
443  Builder->populateFunctionPassManager(*FPM);
444}
445
446void
447LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
448                                                LLVMPassManagerRef PM) {
449  PassManagerBuilder *Builder = unwrap(PMB);
450  PassManagerBase *MPM = unwrap(PM);
451  Builder->populateModulePassManager(*MPM);
452}
453
454void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
455                                                  LLVMPassManagerRef PM,
456                                                  LLVMBool Internalize,
457                                                  LLVMBool RunInliner) {
458  PassManagerBuilder *Builder = unwrap(PMB);
459  PassManagerBase *LPM = unwrap(PM);
460  Builder->populateLTOPassManager(*LPM, Internalize != 0, RunInliner != 0);
461}
462