//===-- llvm/Support/PassManagerBuilder.h - Build Standard Pass -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the PassManagerBuilder class, which is used to set up a
// "standard" optimization sequence suitable for languages like C and C++.
//
// These are implemented as inline functions so that we do not have to worry
// about link issues.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_PASSMANAGERBUILDER_H
#define LLVM_SUPPORT_PASSMANAGERBUILDER_H
#include "llvm/PassManager.h"
#include "llvm/DefaultPasses.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/IPO.h"
namespace llvm {
/// PassManagerBuilder - This class is used to set up a standard optimization
/// sequence for languages like C and C++, allowing some APIs to customize the
/// pass sequence in various ways. A simple example of using it would be:
///
/// PassManagerBuilder Builder;
/// Builder.OptLevel = 2;
/// Builder.populateFunctionPassManager(FPM);
/// Builder.populateModulePassManager(MPM);
///
/// In addition to setting up the basic passes, PassManagerBuilder allows
/// frontends to vend a plugin API, where plugins are allowed to add extensions
/// to the default pass manager. They do this by specifying where in the pass
/// pipeline they want to be added, along with a callback function that adds
/// the pass(es). For example, a plugin that wanted to add a loop optimization
/// could do something like this:
///
/// static void addMyLoopPass(const PMBuilder &Builder, PassManagerBase &PM) {
/// if (Builder.getOptLevel() > 2 && Builder.getOptSizeLevel() == 0)
/// PM.add(createMyAwesomePass());
/// }
/// ...
/// Builder.addExtension(PassManagerBuilder::EP_LoopOptimizerEnd,
/// addMyLoopPass);
/// ...
class PassManagerBuilder {
public:
/// Extensions are passed the builder itself (so they can see how it is
/// configured) as well as the pass manager to add stuff to.
typedef void (*ExtensionFn)(const PassManagerBuilder &Builder,
PassManagerBase &PM);
enum ExtensionPointTy {
/// EP_EarlyAsPossible - This extension point allows adding passes before
/// any other transformations, allowing them to see the code as it is coming
/// out of the frontend.
EP_EarlyAsPossible,
/// EP_LoopOptimizerEnd - This extension point allows adding loop passes to
/// the end of the loop optimizer.
EP_LoopOptimizerEnd
};
/// The Optimization Level - Specify the basic optimization level.
/// 0 = -O0, 1 = -O1, 2 = -O2, 3 = -O3
unsigned OptLevel;
/// SizeLevel - How much we're optimizing for size.
/// 0 = none, 1 = -Os, 2 = -Oz
unsigned SizeLevel;
/// LibraryInfo - Specifies information about the runtime library for the
/// optimizer. If this is non-null, it is added to both the function and
/// per-module pass pipeline.
TargetLibraryInfo *LibraryInfo;
/// Inliner - Specifies the inliner to use. If this is non-null, it is
/// added to the per-module passes.
Pass *Inliner;
bool DisableSimplifyLibCalls;
bool DisableUnitAtATime;
bool DisableUnrollLoops;
private:
/// ExtensionList - This is list of all of the extensions that are registered.
std::vector<std::pair<ExtensionPointTy, ExtensionFn> > Extensions;
public:
PassManagerBuilder() {
OptLevel = 2;
SizeLevel = 0;
LibraryInfo = 0;
Inliner = 0;
DisableSimplifyLibCalls = false;
DisableUnitAtATime = false;
DisableUnrollLoops = false;
}
~PassManagerBuilder() {
delete LibraryInfo;
delete Inliner;
}
void addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
Extensions.push_back(std::make_pair(Ty, Fn));
}
private:
void addExtensionsToPM(ExtensionPointTy ETy, PassManagerBase &PM) const {
for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
if (Extensions[i].first == ETy)
Extensions[i].second(*this, PM);
}
void addInitialAliasAnalysisPasses(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(createTypeBasedAliasAnalysisPass());
PM.add(createBasicAliasAnalysisPass());
}
public:
/// populateFunctionPassManager - This fills in the function pass manager,
/// which is expected to be run on each function immediately as it is
/// generated. The idea is to reduce the size of the IR in memory.
void populateFunctionPassManager(FunctionPassManager &FPM) {
addExtensionsToPM(EP_EarlyAsPossible, FPM);
// Add LibraryInfo if we have some.
if (LibraryInfo) FPM.add(new TargetLibraryInfo(*LibraryInfo));
if (OptLevel == 0) return;
addInitialAliasAnalysisPasses(FPM);
FPM.add(createCFGSimplificationPass());
FPM.add(createScalarReplAggregatesPass());
FPM.add(createEarlyCSEPass());
}
/// populateModulePassManager - This sets up the primary pass manager.
void populateModulePassManager(PassManagerBase &MPM) {
// If all optimizations are disabled, just run the always-inline pass.
if (OptLevel == 0) {
if (Inliner) {
MPM.add(Inliner);
Inliner = 0;
}
return;
}
// Add LibraryInfo if we have some.
if (LibraryInfo) MPM.add(new TargetLibraryInfo(*LibraryInfo));
addInitialAliasAnalysisPasses(MPM);
if (!DisableUnitAtATime) {
MPM.add(createGlobalOptimizerPass()); // Optimize out global vars
MPM.add(createIPSCCPPass()); // IP SCCP
MPM.add(createDeadArgEliminationPass()); // Dead argument elimination
MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
MPM.add(createCFGSimplificationPass()); // Clean up after IPCP & DAE
}
// Start of CallGraph SCC passes.
if (!DisableUnitAtATime)
MPM.add(createPruneEHPass()); // Remove dead EH info
if (Inliner) {
MPM.add(Inliner);
Inliner = 0;
}
if (!DisableUnitAtATime)
MPM.add(createFunctionAttrsPass()); // Set readonly/readnone attrs
if (OptLevel > 2)
MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args
// Start of function pass.
// Break up aggregate allocas, using SSAUpdater.
MPM.add(createScalarReplAggregatesPass(-1, false));
MPM.add(createEarlyCSEPass()); // Catch trivial redundancies
if (!DisableSimplifyLibCalls)
MPM.add(createSimplifyLibCallsPass()); // Library Call Optimizations
MPM.add(createJumpThreadingPass()); // Thread jumps.
MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
MPM.add(createInstructionCombiningPass()); // Combine silly seq's
MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
MPM.add(createReassociatePass()); // Reassociate expressions
MPM.add(createLoopRotatePass()); // Rotate Loop
MPM.add(createLICMPass()); // Hoist loop invariants
MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3));
MPM.add(createInstructionCombiningPass());
MPM.add(createIndVarSimplifyPass()); // Canonicalize indvars
MPM.add(createLoopIdiomPass()); // Recognize idioms like memset.
MPM.add(createLoopDeletionPass()); // Delete dead loops
if (!DisableUnrollLoops)
MPM.add(createLoopUnrollPass()); // Unroll small loops
addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
if (OptLevel > 1)
MPM.add(createGVNPass()); // Remove redundancies
MPM.add(createMemCpyOptPass()); // Remove memcpy / form memset
MPM.add(createSCCPPass()); // Constant prop with SCCP
// Run instcombine after redundancy elimination to exploit opportunities
// opened up by them.
MPM.add(createInstructionCombiningPass());
MPM.add(createJumpThreadingPass()); // Thread jumps
MPM.add(createCorrelatedValuePropagationPass());
MPM.add(createDeadStoreEliminationPass()); // Delete dead stores
MPM.add(createAggressiveDCEPass()); // Delete dead instructions
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
MPM.add(createInstructionCombiningPass()); // Clean up after everything.
if (!DisableUnitAtATime) {
MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
MPM.add(createDeadTypeEliminationPass()); // Eliminate dead types
// GlobalOpt already deletes dead functions and globals, at -O3 try a
// late pass of GlobalDCE. It is capable of deleting dead cycles.
if (OptLevel > 2)
MPM.add(createGlobalDCEPass()); // Remove dead fns and globals.
if (OptLevel > 1)
MPM.add(createConstantMergePass()); // Merge dup global constants
}
}
void populateLTOPassManager(PassManagerBase &PM, bool Internalize,
bool RunInliner) {
// Provide AliasAnalysis services for optimizations.
addInitialAliasAnalysisPasses(PM);
// Now that composite has been compiled, scan through the module, looking
// for a main function. If main is defined, mark all other functions
// internal.
if (Internalize)
PM.add(createInternalizePass(true));
// Propagate constants at call sites into the functions they call. This
// opens opportunities for globalopt (and inlining) by substituting function
// pointers passed as arguments to direct uses of functions.
PM.add(createIPSCCPPass());
// Now that we internalized some globals, see if we can hack on them!
PM.add(createGlobalOptimizerPass());
// Linking modules together can lead to duplicated global constants, only
// keep one copy of each constant.
PM.add(createConstantMergePass());
// Remove unused arguments from functions.
PM.add(createDeadArgEliminationPass());
// Reduce the code after globalopt and ipsccp. Both can open up significant
// simplification opportunities, and both can propagate functions through
// function pointers. When this happens, we often have to resolve varargs
// calls, etc, so let instcombine do this.
PM.add(createInstructionCombiningPass());
// Inline small functions
if (RunInliner)
PM.add(createFunctionInliningPass());
PM.add(createPruneEHPass()); // Remove dead EH info.
// Optimize globals again if we ran the inliner.
if (RunInliner)
PM.add(createGlobalOptimizerPass());
PM.add(createGlobalDCEPass()); // Remove dead functions.
// If we didn't decide to inline a function, check to see if we can
// transform it to pass arguments by value instead of by reference.
PM.add(createArgumentPromotionPass());
// The IPO passes may leave cruft around. Clean up after them.
PM.add(createInstructionCombiningPass());
PM.add(createJumpThreadingPass());
// Break up allocas
PM.add(createScalarReplAggregatesPass());
// Run a few AA driven optimizations here and now, to cleanup the code.
PM.add(createFunctionAttrsPass()); // Add nocapture.
PM.add(createGlobalsModRefPass()); // IP alias analysis.
PM.add(createLICMPass()); // Hoist loop invariants.
PM.add(createGVNPass()); // Remove redundancies.
PM.add(createMemCpyOptPass()); // Remove dead memcpys.
// Nuke dead stores.
PM.add(createDeadStoreEliminationPass());
// Cleanup and simplify the code after the scalar optimizations.
PM.add(createInstructionCombiningPass());
PM.add(createJumpThreadingPass());
// Delete basic blocks, which optimization passes may have killed.
PM.add(createCFGSimplificationPass());
// Now that we have optimized the program, discard unreachable functions.
PM.add(createGlobalDCEPass());
}
};
} // end namespace llvm
#endif
