| //===- PassManagerBuilder.cpp - Build Standard Pass -----------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines the PassManagerBuilder class, which is used to set up a |
| // "standard" optimization sequence suitable for languages like C and C++. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/IPO/PassManagerBuilder.h" |
| #include "llvm-c/Transforms/PassManagerBuilder.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/Analysis/GlobalsModRef.h" |
| #include "llvm/Analysis/ScopedNoAliasAA.h" |
| #include "llvm/Analysis/TargetLibraryInfo.h" |
| #include "llvm/Analysis/TypeBasedAliasAnalysis.h" |
| #include "llvm/IR/LegacyPassManager.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/ManagedStatic.h" |
| #include "llvm/Target/CGPassBuilderOption.h" |
| #include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h" |
| #include "llvm/Transforms/IPO.h" |
| #include "llvm/Transforms/IPO/Attributor.h" |
| #include "llvm/Transforms/IPO/ForceFunctionAttrs.h" |
| #include "llvm/Transforms/IPO/FunctionAttrs.h" |
| #include "llvm/Transforms/IPO/InferFunctionAttrs.h" |
| #include "llvm/Transforms/InstCombine/InstCombine.h" |
| #include "llvm/Transforms/Instrumentation.h" |
| #include "llvm/Transforms/Scalar.h" |
| #include "llvm/Transforms/Scalar/GVN.h" |
| #include "llvm/Transforms/Scalar/LICM.h" |
| #include "llvm/Transforms/Scalar/LoopUnrollPass.h" |
| #include "llvm/Transforms/Scalar/SimpleLoopUnswitch.h" |
| #include "llvm/Transforms/Utils.h" |
| #include "llvm/Transforms/Vectorize.h" |
| |
| using namespace llvm; |
| |
| PassManagerBuilder::PassManagerBuilder() { |
| OptLevel = 2; |
| SizeLevel = 0; |
| LibraryInfo = nullptr; |
| Inliner = nullptr; |
| DisableUnrollLoops = false; |
| SLPVectorize = false; |
| LoopVectorize = true; |
| LoopsInterleaved = true; |
| LicmMssaOptCap = SetLicmMssaOptCap; |
| LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap; |
| DisableGVNLoadPRE = false; |
| ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll; |
| VerifyInput = false; |
| VerifyOutput = false; |
| MergeFunctions = false; |
| DivergentTarget = false; |
| CallGraphProfile = true; |
| } |
| |
| PassManagerBuilder::~PassManagerBuilder() { |
| delete LibraryInfo; |
| delete Inliner; |
| } |
| |
| void PassManagerBuilder::addInitialAliasAnalysisPasses( |
| legacy::PassManagerBase &PM) const { |
| // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that |
| // BasicAliasAnalysis wins if they disagree. This is intended to help |
| // support "obvious" type-punning idioms. |
| PM.add(createTypeBasedAAWrapperPass()); |
| PM.add(createScopedNoAliasAAWrapperPass()); |
| } |
| |
| void PassManagerBuilder::populateFunctionPassManager( |
| legacy::FunctionPassManager &FPM) { |
| // Add LibraryInfo if we have some. |
| if (LibraryInfo) |
| FPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); |
| |
| if (OptLevel == 0) return; |
| |
| addInitialAliasAnalysisPasses(FPM); |
| |
| // Lower llvm.expect to metadata before attempting transforms. |
| // Compare/branch metadata may alter the behavior of passes like SimplifyCFG. |
| FPM.add(createLowerExpectIntrinsicPass()); |
| FPM.add(createCFGSimplificationPass()); |
| FPM.add(createSROAPass()); |
| FPM.add(createEarlyCSEPass()); |
| } |
| |
| void PassManagerBuilder::addFunctionSimplificationPasses( |
| legacy::PassManagerBase &MPM) { |
| // Start of function pass. |
| // Break up aggregate allocas, using SSAUpdater. |
| assert(OptLevel >= 1 && "Calling function optimizer with no optimization level!"); |
| MPM.add(createSROAPass()); |
| MPM.add(createEarlyCSEPass(true /* Enable mem-ssa. */)); // Catch trivial redundancies |
| |
| if (OptLevel > 1) { |
| // Speculative execution if the target has divergent branches; otherwise nop. |
| MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass()); |
| |
| MPM.add(createJumpThreadingPass()); // Thread jumps. |
| MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals |
| } |
| MPM.add( |
| createCFGSimplificationPass(SimplifyCFGOptions().convertSwitchRangeToICmp( |
| true))); // Merge & remove BBs |
| // Combine silly seq's |
| MPM.add(createInstructionCombiningPass()); |
| if (SizeLevel == 0) |
| MPM.add(createLibCallsShrinkWrapPass()); |
| |
| // TODO: Investigate the cost/benefit of tail call elimination on debugging. |
| if (OptLevel > 1) |
| MPM.add(createTailCallEliminationPass()); // Eliminate tail calls |
| MPM.add( |
| createCFGSimplificationPass(SimplifyCFGOptions().convertSwitchRangeToICmp( |
| true))); // Merge & remove BBs |
| MPM.add(createReassociatePass()); // Reassociate expressions |
| |
| // Begin the loop pass pipeline. |
| |
| // The simple loop unswitch pass relies on separate cleanup passes. Schedule |
| // them first so when we re-process a loop they run before other loop |
| // passes. |
| MPM.add(createLoopInstSimplifyPass()); |
| MPM.add(createLoopSimplifyCFGPass()); |
| |
| // Try to remove as much code from the loop header as possible, |
| // to reduce amount of IR that will have to be duplicated. However, |
| // do not perform speculative hoisting the first time as LICM |
| // will destroy metadata that may not need to be destroyed if run |
| // after loop rotation. |
| // TODO: Investigate promotion cap for O1. |
| MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap, |
| /*AllowSpeculation=*/false)); |
| // Rotate Loop - disable header duplication at -Oz |
| MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1, false)); |
| // TODO: Investigate promotion cap for O1. |
| MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap, |
| /*AllowSpeculation=*/true)); |
| MPM.add(createSimpleLoopUnswitchLegacyPass(OptLevel == 3)); |
| // FIXME: We break the loop pass pipeline here in order to do full |
| // simplifycfg. Eventually loop-simplifycfg should be enhanced to replace the |
| // need for this. |
| MPM.add(createCFGSimplificationPass( |
| SimplifyCFGOptions().convertSwitchRangeToICmp(true))); |
| MPM.add(createInstructionCombiningPass()); |
| // We resume loop passes creating a second loop pipeline here. |
| MPM.add(createLoopIdiomPass()); // Recognize idioms like memset. |
| MPM.add(createIndVarSimplifyPass()); // Canonicalize indvars |
| MPM.add(createLoopDeletionPass()); // Delete dead loops |
| |
| // Unroll small loops and perform peeling. |
| MPM.add(createSimpleLoopUnrollPass(OptLevel, DisableUnrollLoops, |
| ForgetAllSCEVInLoopUnroll)); |
| // This ends the loop pass pipelines. |
| |
| // Break up allocas that may now be splittable after loop unrolling. |
| MPM.add(createSROAPass()); |
| |
| if (OptLevel > 1) { |
| MPM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds |
| MPM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies |
| } |
| MPM.add(createSCCPPass()); // Constant prop with SCCP |
| |
| // Delete dead bit computations (instcombine runs after to fold away the dead |
| // computations, and then ADCE will run later to exploit any new DCE |
| // opportunities that creates). |
| MPM.add(createBitTrackingDCEPass()); // Delete dead bit computations |
| |
| // Run instcombine after redundancy elimination to exploit opportunities |
| // opened up by them. |
| MPM.add(createInstructionCombiningPass()); |
| if (OptLevel > 1) { |
| MPM.add(createJumpThreadingPass()); // Thread jumps |
| MPM.add(createCorrelatedValuePropagationPass()); |
| } |
| MPM.add(createAggressiveDCEPass()); // Delete dead instructions |
| |
| MPM.add(createMemCpyOptPass()); // Remove memcpy / form memset |
| // TODO: Investigate if this is too expensive at O1. |
| if (OptLevel > 1) { |
| MPM.add(createDeadStoreEliminationPass()); // Delete dead stores |
| MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap, |
| /*AllowSpeculation=*/true)); |
| } |
| |
| // Merge & remove BBs and sink & hoist common instructions. |
| MPM.add(createCFGSimplificationPass( |
| SimplifyCFGOptions().hoistCommonInsts(true).sinkCommonInsts(true))); |
| // Clean up after everything. |
| MPM.add(createInstructionCombiningPass()); |
| } |
| |
| /// FIXME: Should LTO cause any differences to this set of passes? |
| void PassManagerBuilder::addVectorPasses(legacy::PassManagerBase &PM, |
| bool IsFullLTO) { |
| PM.add(createLoopVectorizePass(!LoopsInterleaved, !LoopVectorize)); |
| |
| if (IsFullLTO) { |
| // The vectorizer may have significantly shortened a loop body; unroll |
| // again. Unroll small loops to hide loop backedge latency and saturate any |
| // parallel execution resources of an out-of-order processor. We also then |
| // need to clean up redundancies and loop invariant code. |
| // FIXME: It would be really good to use a loop-integrated instruction |
| // combiner for cleanup here so that the unrolling and LICM can be pipelined |
| // across the loop nests. |
| PM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops, |
| ForgetAllSCEVInLoopUnroll)); |
| PM.add(createWarnMissedTransformationsPass()); |
| } |
| |
| if (!IsFullLTO) { |
| // Eliminate loads by forwarding stores from the previous iteration to loads |
| // of the current iteration. |
| PM.add(createLoopLoadEliminationPass()); |
| } |
| // Cleanup after the loop optimization passes. |
| PM.add(createInstructionCombiningPass()); |
| |
| // Now that we've formed fast to execute loop structures, we do further |
| // optimizations. These are run afterward as they might block doing complex |
| // analyses and transforms such as what are needed for loop vectorization. |
| |
| // Cleanup after loop vectorization, etc. Simplification passes like CVP and |
| // GVN, loop transforms, and others have already run, so it's now better to |
| // convert to more optimized IR using more aggressive simplify CFG options. |
| // The extra sinking transform can create larger basic blocks, so do this |
| // before SLP vectorization. |
| PM.add(createCFGSimplificationPass(SimplifyCFGOptions() |
| .forwardSwitchCondToPhi(true) |
| .convertSwitchRangeToICmp(true) |
| .convertSwitchToLookupTable(true) |
| .needCanonicalLoops(false) |
| .hoistCommonInsts(true) |
| .sinkCommonInsts(true))); |
| |
| if (IsFullLTO) { |
| PM.add(createSCCPPass()); // Propagate exposed constants |
| PM.add(createInstructionCombiningPass()); // Clean up again |
| PM.add(createBitTrackingDCEPass()); |
| } |
| |
| // Optimize parallel scalar instruction chains into SIMD instructions. |
| if (SLPVectorize) { |
| PM.add(createSLPVectorizerPass()); |
| } |
| |
| // Enhance/cleanup vector code. |
| PM.add(createVectorCombinePass()); |
| |
| if (!IsFullLTO) { |
| PM.add(createInstructionCombiningPass()); |
| |
| // Unroll small loops |
| PM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops, |
| ForgetAllSCEVInLoopUnroll)); |
| |
| if (!DisableUnrollLoops) { |
| // LoopUnroll may generate some redundency to cleanup. |
| PM.add(createInstructionCombiningPass()); |
| |
| // Runtime unrolling will introduce runtime check in loop prologue. If the |
| // unrolled loop is a inner loop, then the prologue will be inside the |
| // outer loop. LICM pass can help to promote the runtime check out if the |
| // checked value is loop invariant. |
| PM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap, |
| /*AllowSpeculation=*/true)); |
| } |
| |
| PM.add(createWarnMissedTransformationsPass()); |
| } |
| |
| // After vectorization and unrolling, assume intrinsics may tell us more |
| // about pointer alignments. |
| PM.add(createAlignmentFromAssumptionsPass()); |
| |
| if (IsFullLTO) |
| PM.add(createInstructionCombiningPass()); |
| } |
| |
| void PassManagerBuilder::populateModulePassManager( |
| legacy::PassManagerBase &MPM) { |
| MPM.add(createAnnotation2MetadataLegacyPass()); |
| |
| // Allow forcing function attributes as a debugging and tuning aid. |
| MPM.add(createForceFunctionAttrsLegacyPass()); |
| |
| // If all optimizations are disabled, just run the always-inline pass and, |
| // if enabled, the function merging pass. |
| if (OptLevel == 0) { |
| if (Inliner) { |
| MPM.add(Inliner); |
| Inliner = nullptr; |
| } |
| |
| // FIXME: The BarrierNoopPass is a HACK! The inliner pass above implicitly |
| // creates a CGSCC pass manager, but we don't want to add extensions into |
| // that pass manager. To prevent this we insert a no-op module pass to reset |
| // the pass manager to get the same behavior as EP_OptimizerLast in non-O0 |
| // builds. The function merging pass is |
| if (MergeFunctions) |
| MPM.add(createMergeFunctionsPass()); |
| return; |
| } |
| |
| // Add LibraryInfo if we have some. |
| if (LibraryInfo) |
| MPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); |
| |
| addInitialAliasAnalysisPasses(MPM); |
| |
| // Infer attributes about declarations if possible. |
| MPM.add(createInferFunctionAttrsLegacyPass()); |
| |
| if (OptLevel > 2) |
| MPM.add(createCallSiteSplittingPass()); |
| |
| MPM.add(createIPSCCPPass()); // IP SCCP |
| MPM.add(createCalledValuePropagationPass()); |
| |
| MPM.add(createGlobalOptimizerPass()); // Optimize out global vars |
| // Promote any localized global vars. |
| MPM.add(createPromoteMemoryToRegisterPass()); |
| |
| MPM.add(createDeadArgEliminationPass()); // Dead argument elimination |
| |
| MPM.add(createInstructionCombiningPass()); // Clean up after IPCP & DAE |
| MPM.add( |
| createCFGSimplificationPass(SimplifyCFGOptions().convertSwitchRangeToICmp( |
| true))); // Clean up after IPCP & DAE |
| |
| // We add a module alias analysis pass here. In part due to bugs in the |
| // analysis infrastructure this "works" in that the analysis stays alive |
| // for the entire SCC pass run below. |
| MPM.add(createGlobalsAAWrapperPass()); |
| |
| // Start of CallGraph SCC passes. |
| bool RunInliner = false; |
| if (Inliner) { |
| MPM.add(Inliner); |
| Inliner = nullptr; |
| RunInliner = true; |
| } |
| |
| MPM.add(createPostOrderFunctionAttrsLegacyPass()); |
| |
| addFunctionSimplificationPasses(MPM); |
| |
| // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC |
| // pass manager that we are specifically trying to avoid. To prevent this |
| // we must insert a no-op module pass to reset the pass manager. |
| MPM.add(createBarrierNoopPass()); |
| |
| if (OptLevel > 1) |
| // Remove avail extern fns and globals definitions if we aren't |
| // compiling an object file for later LTO. For LTO we want to preserve |
| // these so they are eligible for inlining at link-time. Note if they |
| // are unreferenced they will be removed by GlobalDCE later, so |
| // this only impacts referenced available externally globals. |
| // Eventually they will be suppressed during codegen, but eliminating |
| // here enables more opportunity for GlobalDCE as it may make |
| // globals referenced by available external functions dead |
| // and saves running remaining passes on the eliminated functions. |
| MPM.add(createEliminateAvailableExternallyPass()); |
| |
| MPM.add(createReversePostOrderFunctionAttrsPass()); |
| |
| // The inliner performs some kind of dead code elimination as it goes, |
| // but there are cases that are not really caught by it. We might |
| // at some point consider teaching the inliner about them, but it |
| // is OK for now to run GlobalOpt + GlobalDCE in tandem as their |
| // benefits generally outweight the cost, making the whole pipeline |
| // faster. |
| if (RunInliner) { |
| MPM.add(createGlobalOptimizerPass()); |
| MPM.add(createGlobalDCEPass()); |
| } |
| |
| // We add a fresh GlobalsModRef run at this point. This is particularly |
| // useful as the above will have inlined, DCE'ed, and function-attr |
| // propagated everything. We should at this point have a reasonably minimal |
| // and richly annotated call graph. By computing aliasing and mod/ref |
| // information for all local globals here, the late loop passes and notably |
| // the vectorizer will be able to use them to help recognize vectorizable |
| // memory operations. |
| // |
| // Note that this relies on a bug in the pass manager which preserves |
| // a module analysis into a function pass pipeline (and throughout it) so |
| // long as the first function pass doesn't invalidate the module analysis. |
| // Thus both Float2Int and LoopRotate have to preserve AliasAnalysis for |
| // this to work. Fortunately, it is trivial to preserve AliasAnalysis |
| // (doing nothing preserves it as it is required to be conservatively |
| // correct in the face of IR changes). |
| MPM.add(createGlobalsAAWrapperPass()); |
| |
| MPM.add(createFloat2IntPass()); |
| MPM.add(createLowerConstantIntrinsicsPass()); |
| |
| // Re-rotate loops in all our loop nests. These may have fallout out of |
| // rotated form due to GVN or other transformations, and the vectorizer relies |
| // on the rotated form. Disable header duplication at -Oz. |
| MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1, false)); |
| |
| // Distribute loops to allow partial vectorization. I.e. isolate dependences |
| // into separate loop that would otherwise inhibit vectorization. This is |
| // currently only performed for loops marked with the metadata |
| // llvm.loop.distribute=true or when -enable-loop-distribute is specified. |
| MPM.add(createLoopDistributePass()); |
| |
| addVectorPasses(MPM, /* IsFullLTO */ false); |
| |
| // FIXME: We shouldn't bother with this anymore. |
| MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes |
| |
| // GlobalOpt already deletes dead functions and globals, at -O2 try a |
| // late pass of GlobalDCE. It is capable of deleting dead cycles. |
| if (OptLevel > 1) { |
| MPM.add(createGlobalDCEPass()); // Remove dead fns and globals. |
| MPM.add(createConstantMergePass()); // Merge dup global constants |
| } |
| |
| if (MergeFunctions) |
| MPM.add(createMergeFunctionsPass()); |
| |
| // LoopSink pass sinks instructions hoisted by LICM, which serves as a |
| // canonicalization pass that enables other optimizations. As a result, |
| // LoopSink pass needs to be a very late IR pass to avoid undoing LICM |
| // result too early. |
| MPM.add(createLoopSinkPass()); |
| // Get rid of LCSSA nodes. |
| MPM.add(createInstSimplifyLegacyPass()); |
| |
| // This hoists/decomposes div/rem ops. It should run after other sink/hoist |
| // passes to avoid re-sinking, but before SimplifyCFG because it can allow |
| // flattening of blocks. |
| MPM.add(createDivRemPairsPass()); |
| |
| // LoopSink (and other loop passes since the last simplifyCFG) might have |
| // resulted in single-entry-single-exit or empty blocks. Clean up the CFG. |
| MPM.add(createCFGSimplificationPass( |
| SimplifyCFGOptions().convertSwitchRangeToICmp(true))); |
| } |
| |
| LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() { |
| PassManagerBuilder *PMB = new PassManagerBuilder(); |
| return wrap(PMB); |
| } |
| |
| void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) { |
| PassManagerBuilder *Builder = unwrap(PMB); |
| delete Builder; |
| } |
| |
| void |
| LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB, |
| unsigned OptLevel) { |
| PassManagerBuilder *Builder = unwrap(PMB); |
| Builder->OptLevel = OptLevel; |
| } |
| |
| void |
| LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB, |
| unsigned SizeLevel) { |
| PassManagerBuilder *Builder = unwrap(PMB); |
| Builder->SizeLevel = SizeLevel; |
| } |
| |
| void |
| LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB, |
| LLVMBool Value) { |
| // NOTE: The DisableUnitAtATime switch has been removed. |
| } |
| |
| void |
| LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB, |
| LLVMBool Value) { |
| PassManagerBuilder *Builder = unwrap(PMB); |
| Builder->DisableUnrollLoops = Value; |
| } |
| |
| void |
| LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB, |
| LLVMBool Value) { |
| // NOTE: The simplify-libcalls pass has been removed. |
| } |
| |
| void |
| LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB, |
| unsigned Threshold) { |
| PassManagerBuilder *Builder = unwrap(PMB); |
| Builder->Inliner = createFunctionInliningPass(Threshold); |
| } |
| |
| void |
| LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB, |
| LLVMPassManagerRef PM) { |
| PassManagerBuilder *Builder = unwrap(PMB); |
| legacy::FunctionPassManager *FPM = unwrap<legacy::FunctionPassManager>(PM); |
| Builder->populateFunctionPassManager(*FPM); |
| } |
| |
| void |
| LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB, |
| LLVMPassManagerRef PM) { |
| PassManagerBuilder *Builder = unwrap(PMB); |
| legacy::PassManagerBase *MPM = unwrap(PM); |
| Builder->populateModulePassManager(*MPM); |
| } |