llvm-project/llvm/lib/CodeGen/TargetPassConfig.cpp

931 lines
35 KiB
C++

//===-- TargetPassConfig.cpp - Target independent code generation passes --===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines interfaces to access the target independent code
// generation passes provided by the LLVM backend.
//
//===---------------------------------------------------------------------===//
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/CFLAndersAliasAnalysis.h"
#include "llvm/Analysis/CFLSteensAliasAnalysis.h"
#include "llvm/Analysis/CallGraphSCCPass.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/ScopedNoAliasAA.h"
#include "llvm/Analysis/TypeBasedAliasAnalysis.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/RegAllocRegistry.h"
#include "llvm/CodeGen/RegisterUsageInfo.h"
#include "llvm/IR/IRPrintingPasses.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Verifier.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/SymbolRewriter.h"
using namespace llvm;
static cl::opt<bool> DisablePostRASched("disable-post-ra", cl::Hidden,
cl::desc("Disable Post Regalloc Scheduler"));
static cl::opt<bool> DisableBranchFold("disable-branch-fold", cl::Hidden,
cl::desc("Disable branch folding"));
static cl::opt<bool> DisableTailDuplicate("disable-tail-duplicate", cl::Hidden,
cl::desc("Disable tail duplication"));
static cl::opt<bool> DisableEarlyTailDup("disable-early-taildup", cl::Hidden,
cl::desc("Disable pre-register allocation tail duplication"));
static cl::opt<bool> DisableBlockPlacement("disable-block-placement",
cl::Hidden, cl::desc("Disable probability-driven block placement"));
static cl::opt<bool> EnableBlockPlacementStats("enable-block-placement-stats",
cl::Hidden, cl::desc("Collect probability-driven block placement stats"));
static cl::opt<bool> DisableSSC("disable-ssc", cl::Hidden,
cl::desc("Disable Stack Slot Coloring"));
static cl::opt<bool> DisableMachineDCE("disable-machine-dce", cl::Hidden,
cl::desc("Disable Machine Dead Code Elimination"));
static cl::opt<bool> DisableEarlyIfConversion("disable-early-ifcvt", cl::Hidden,
cl::desc("Disable Early If-conversion"));
static cl::opt<bool> DisableMachineLICM("disable-machine-licm", cl::Hidden,
cl::desc("Disable Machine LICM"));
static cl::opt<bool> DisableMachineCSE("disable-machine-cse", cl::Hidden,
cl::desc("Disable Machine Common Subexpression Elimination"));
static cl::opt<cl::boolOrDefault> OptimizeRegAlloc(
"optimize-regalloc", cl::Hidden,
cl::desc("Enable optimized register allocation compilation path."));
static cl::opt<bool> DisablePostRAMachineLICM("disable-postra-machine-licm",
cl::Hidden,
cl::desc("Disable Machine LICM"));
static cl::opt<bool> DisableMachineSink("disable-machine-sink", cl::Hidden,
cl::desc("Disable Machine Sinking"));
static cl::opt<bool> DisableLSR("disable-lsr", cl::Hidden,
cl::desc("Disable Loop Strength Reduction Pass"));
static cl::opt<bool> DisableConstantHoisting("disable-constant-hoisting",
cl::Hidden, cl::desc("Disable ConstantHoisting"));
static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
cl::desc("Disable Codegen Prepare"));
static cl::opt<bool> DisableCopyProp("disable-copyprop", cl::Hidden,
cl::desc("Disable Copy Propagation pass"));
static cl::opt<bool> DisablePartialLibcallInlining("disable-partial-libcall-inlining",
cl::Hidden, cl::desc("Disable Partial Libcall Inlining"));
static cl::opt<bool> EnableImplicitNullChecks(
"enable-implicit-null-checks",
cl::desc("Fold null checks into faulting memory operations"),
cl::init(false));
static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
cl::desc("Print LLVM IR produced by the loop-reduce pass"));
static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
cl::desc("Print LLVM IR input to isel pass"));
static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
cl::desc("Dump garbage collector data"));
static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
cl::desc("Verify generated machine code"),
cl::init(false),
cl::ZeroOrMore);
static cl::opt<bool> EnableMachineOutliner("enable-machine-outliner",
cl::Hidden,
cl::desc("Enable machine outliner"));
static cl::opt<std::string>
PrintMachineInstrs("print-machineinstrs", cl::ValueOptional,
cl::desc("Print machine instrs"),
cl::value_desc("pass-name"), cl::init("option-unspecified"));
static cl::opt<int> EnableGlobalISelAbort(
"global-isel-abort", cl::Hidden,
cl::desc("Enable abort calls when \"global\" instruction selection "
"fails to lower/select an instruction: 0 disable the abort, "
"1 enable the abort, and "
"2 disable the abort but emit a diagnostic on failure"),
cl::init(1));
// Temporary option to allow experimenting with MachineScheduler as a post-RA
// scheduler. Targets can "properly" enable this with
// substitutePass(&PostRASchedulerID, &PostMachineSchedulerID).
// Targets can return true in targetSchedulesPostRAScheduling() and
// insert a PostRA scheduling pass wherever it wants.
cl::opt<bool> MISchedPostRA("misched-postra", cl::Hidden,
cl::desc("Run MachineScheduler post regalloc (independent of preRA sched)"));
// Experimental option to run live interval analysis early.
static cl::opt<bool> EarlyLiveIntervals("early-live-intervals", cl::Hidden,
cl::desc("Run live interval analysis earlier in the pipeline"));
// Experimental option to use CFL-AA in codegen
enum class CFLAAType { None, Steensgaard, Andersen, Both };
static cl::opt<CFLAAType> UseCFLAA(
"use-cfl-aa-in-codegen", cl::init(CFLAAType::None), cl::Hidden,
cl::desc("Enable the new, experimental CFL alias analysis in CodeGen"),
cl::values(clEnumValN(CFLAAType::None, "none", "Disable CFL-AA"),
clEnumValN(CFLAAType::Steensgaard, "steens",
"Enable unification-based CFL-AA"),
clEnumValN(CFLAAType::Andersen, "anders",
"Enable inclusion-based CFL-AA"),
clEnumValN(CFLAAType::Both, "both",
"Enable both variants of CFL-AA")));
/// Allow standard passes to be disabled by command line options. This supports
/// simple binary flags that either suppress the pass or do nothing.
/// i.e. -disable-mypass=false has no effect.
/// These should be converted to boolOrDefault in order to use applyOverride.
static IdentifyingPassPtr applyDisable(IdentifyingPassPtr PassID,
bool Override) {
if (Override)
return IdentifyingPassPtr();
return PassID;
}
/// Allow standard passes to be disabled by the command line, regardless of who
/// is adding the pass.
///
/// StandardID is the pass identified in the standard pass pipeline and provided
/// to addPass(). It may be a target-specific ID in the case that the target
/// directly adds its own pass, but in that case we harmlessly fall through.
///
/// TargetID is the pass that the target has configured to override StandardID.
///
/// StandardID may be a pseudo ID. In that case TargetID is the name of the real
/// pass to run. This allows multiple options to control a single pass depending
/// on where in the pipeline that pass is added.
static IdentifyingPassPtr overridePass(AnalysisID StandardID,
IdentifyingPassPtr TargetID) {
if (StandardID == &PostRASchedulerID)
return applyDisable(TargetID, DisablePostRASched);
if (StandardID == &BranchFolderPassID)
return applyDisable(TargetID, DisableBranchFold);
if (StandardID == &TailDuplicateID)
return applyDisable(TargetID, DisableTailDuplicate);
if (StandardID == &TargetPassConfig::EarlyTailDuplicateID)
return applyDisable(TargetID, DisableEarlyTailDup);
if (StandardID == &MachineBlockPlacementID)
return applyDisable(TargetID, DisableBlockPlacement);
if (StandardID == &StackSlotColoringID)
return applyDisable(TargetID, DisableSSC);
if (StandardID == &DeadMachineInstructionElimID)
return applyDisable(TargetID, DisableMachineDCE);
if (StandardID == &EarlyIfConverterID)
return applyDisable(TargetID, DisableEarlyIfConversion);
if (StandardID == &MachineLICMID)
return applyDisable(TargetID, DisableMachineLICM);
if (StandardID == &MachineCSEID)
return applyDisable(TargetID, DisableMachineCSE);
if (StandardID == &TargetPassConfig::PostRAMachineLICMID)
return applyDisable(TargetID, DisablePostRAMachineLICM);
if (StandardID == &MachineSinkingID)
return applyDisable(TargetID, DisableMachineSink);
if (StandardID == &MachineCopyPropagationID)
return applyDisable(TargetID, DisableCopyProp);
return TargetID;
}
//===---------------------------------------------------------------------===//
/// TargetPassConfig
//===---------------------------------------------------------------------===//
INITIALIZE_PASS(TargetPassConfig, "targetpassconfig",
"Target Pass Configuration", false, false)
char TargetPassConfig::ID = 0;
// Pseudo Pass IDs.
char TargetPassConfig::EarlyTailDuplicateID = 0;
char TargetPassConfig::PostRAMachineLICMID = 0;
namespace {
struct InsertedPass {
AnalysisID TargetPassID;
IdentifyingPassPtr InsertedPassID;
bool VerifyAfter;
bool PrintAfter;
InsertedPass(AnalysisID TargetPassID, IdentifyingPassPtr InsertedPassID,
bool VerifyAfter, bool PrintAfter)
: TargetPassID(TargetPassID), InsertedPassID(InsertedPassID),
VerifyAfter(VerifyAfter), PrintAfter(PrintAfter) {}
Pass *getInsertedPass() const {
assert(InsertedPassID.isValid() && "Illegal Pass ID!");
if (InsertedPassID.isInstance())
return InsertedPassID.getInstance();
Pass *NP = Pass::createPass(InsertedPassID.getID());
assert(NP && "Pass ID not registered");
return NP;
}
};
}
namespace llvm {
class PassConfigImpl {
public:
// List of passes explicitly substituted by this target. Normally this is
// empty, but it is a convenient way to suppress or replace specific passes
// that are part of a standard pass pipeline without overridding the entire
// pipeline. This mechanism allows target options to inherit a standard pass's
// user interface. For example, a target may disable a standard pass by
// default by substituting a pass ID of zero, and the user may still enable
// that standard pass with an explicit command line option.
DenseMap<AnalysisID,IdentifyingPassPtr> TargetPasses;
/// Store the pairs of <AnalysisID, AnalysisID> of which the second pass
/// is inserted after each instance of the first one.
SmallVector<InsertedPass, 4> InsertedPasses;
};
} // namespace llvm
// Out of line virtual method.
TargetPassConfig::~TargetPassConfig() {
delete Impl;
}
// Out of line constructor provides default values for pass options and
// registers all common codegen passes.
TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm)
: ImmutablePass(ID), PM(&pm), Started(true), Stopped(false),
AddingMachinePasses(false), TM(tm), Impl(nullptr), Initialized(false),
DisableVerify(false), EnableTailMerge(true) {
Impl = new PassConfigImpl();
// Register all target independent codegen passes to activate their PassIDs,
// including this pass itself.
initializeCodeGen(*PassRegistry::getPassRegistry());
// Also register alias analysis passes required by codegen passes.
initializeBasicAAWrapperPassPass(*PassRegistry::getPassRegistry());
initializeAAResultsWrapperPassPass(*PassRegistry::getPassRegistry());
// Substitute Pseudo Pass IDs for real ones.
substitutePass(&EarlyTailDuplicateID, &TailDuplicateID);
substitutePass(&PostRAMachineLICMID, &MachineLICMID);
if (StringRef(PrintMachineInstrs.getValue()).equals(""))
TM->Options.PrintMachineCode = true;
}
CodeGenOpt::Level TargetPassConfig::getOptLevel() const {
return TM->getOptLevel();
}
/// Insert InsertedPassID pass after TargetPassID.
void TargetPassConfig::insertPass(AnalysisID TargetPassID,
IdentifyingPassPtr InsertedPassID,
bool VerifyAfter, bool PrintAfter) {
assert(((!InsertedPassID.isInstance() &&
TargetPassID != InsertedPassID.getID()) ||
(InsertedPassID.isInstance() &&
TargetPassID != InsertedPassID.getInstance()->getPassID())) &&
"Insert a pass after itself!");
Impl->InsertedPasses.emplace_back(TargetPassID, InsertedPassID, VerifyAfter,
PrintAfter);
}
/// createPassConfig - Create a pass configuration object to be used by
/// addPassToEmitX methods for generating a pipeline of CodeGen passes.
///
/// Targets may override this to extend TargetPassConfig.
TargetPassConfig *LLVMTargetMachine::createPassConfig(PassManagerBase &PM) {
return new TargetPassConfig(this, PM);
}
TargetPassConfig::TargetPassConfig()
: ImmutablePass(ID), PM(nullptr) {
llvm_unreachable("TargetPassConfig should not be constructed on-the-fly");
}
// Helper to verify the analysis is really immutable.
void TargetPassConfig::setOpt(bool &Opt, bool Val) {
assert(!Initialized && "PassConfig is immutable");
Opt = Val;
}
void TargetPassConfig::substitutePass(AnalysisID StandardID,
IdentifyingPassPtr TargetID) {
Impl->TargetPasses[StandardID] = TargetID;
}
IdentifyingPassPtr TargetPassConfig::getPassSubstitution(AnalysisID ID) const {
DenseMap<AnalysisID, IdentifyingPassPtr>::const_iterator
I = Impl->TargetPasses.find(ID);
if (I == Impl->TargetPasses.end())
return ID;
return I->second;
}
bool TargetPassConfig::isPassSubstitutedOrOverridden(AnalysisID ID) const {
IdentifyingPassPtr TargetID = getPassSubstitution(ID);
IdentifyingPassPtr FinalPtr = overridePass(ID, TargetID);
return !FinalPtr.isValid() || FinalPtr.isInstance() ||
FinalPtr.getID() != ID;
}
/// Add a pass to the PassManager if that pass is supposed to be run. If the
/// Started/Stopped flags indicate either that the compilation should start at
/// a later pass or that it should stop after an earlier pass, then do not add
/// the pass. Finally, compare the current pass against the StartAfter
/// and StopAfter options and change the Started/Stopped flags accordingly.
void TargetPassConfig::addPass(Pass *P, bool verifyAfter, bool printAfter) {
assert(!Initialized && "PassConfig is immutable");
// Cache the Pass ID here in case the pass manager finds this pass is
// redundant with ones already scheduled / available, and deletes it.
// Fundamentally, once we add the pass to the manager, we no longer own it
// and shouldn't reference it.
AnalysisID PassID = P->getPassID();
if (StartBefore == PassID)
Started = true;
if (StopBefore == PassID)
Stopped = true;
if (Started && !Stopped) {
std::string Banner;
// Construct banner message before PM->add() as that may delete the pass.
if (AddingMachinePasses && (printAfter || verifyAfter))
Banner = std::string("After ") + std::string(P->getPassName());
PM->add(P);
if (AddingMachinePasses) {
if (printAfter)
addPrintPass(Banner);
if (verifyAfter)
addVerifyPass(Banner);
}
// Add the passes after the pass P if there is any.
for (auto IP : Impl->InsertedPasses) {
if (IP.TargetPassID == PassID)
addPass(IP.getInsertedPass(), IP.VerifyAfter, IP.PrintAfter);
}
} else {
delete P;
}
if (StopAfter == PassID)
Stopped = true;
if (StartAfter == PassID)
Started = true;
if (Stopped && !Started)
report_fatal_error("Cannot stop compilation after pass that is not run");
}
/// Add a CodeGen pass at this point in the pipeline after checking for target
/// and command line overrides.
///
/// addPass cannot return a pointer to the pass instance because is internal the
/// PassManager and the instance we create here may already be freed.
AnalysisID TargetPassConfig::addPass(AnalysisID PassID, bool verifyAfter,
bool printAfter) {
IdentifyingPassPtr TargetID = getPassSubstitution(PassID);
IdentifyingPassPtr FinalPtr = overridePass(PassID, TargetID);
if (!FinalPtr.isValid())
return nullptr;
Pass *P;
if (FinalPtr.isInstance())
P = FinalPtr.getInstance();
else {
P = Pass::createPass(FinalPtr.getID());
if (!P)
llvm_unreachable("Pass ID not registered");
}
AnalysisID FinalID = P->getPassID();
addPass(P, verifyAfter, printAfter); // Ends the lifetime of P.
return FinalID;
}
void TargetPassConfig::printAndVerify(const std::string &Banner) {
addPrintPass(Banner);
addVerifyPass(Banner);
}
void TargetPassConfig::addPrintPass(const std::string &Banner) {
if (TM->shouldPrintMachineCode())
PM->add(createMachineFunctionPrinterPass(dbgs(), Banner));
}
void TargetPassConfig::addVerifyPass(const std::string &Banner) {
if (VerifyMachineCode)
PM->add(createMachineVerifierPass(Banner));
}
/// Add common target configurable passes that perform LLVM IR to IR transforms
/// following machine independent optimization.
void TargetPassConfig::addIRPasses() {
switch (UseCFLAA) {
case CFLAAType::Steensgaard:
addPass(createCFLSteensAAWrapperPass());
break;
case CFLAAType::Andersen:
addPass(createCFLAndersAAWrapperPass());
break;
case CFLAAType::Both:
addPass(createCFLAndersAAWrapperPass());
addPass(createCFLSteensAAWrapperPass());
break;
default:
break;
}
// Basic AliasAnalysis support.
// Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
// BasicAliasAnalysis wins if they disagree. This is intended to help
// support "obvious" type-punning idioms.
addPass(createTypeBasedAAWrapperPass());
addPass(createScopedNoAliasAAWrapperPass());
addPass(createBasicAAWrapperPass());
// Before running any passes, run the verifier to determine if the input
// coming from the front-end and/or optimizer is valid.
if (!DisableVerify)
addPass(createVerifierPass());
// Run loop strength reduction before anything else.
if (getOptLevel() != CodeGenOpt::None && !DisableLSR) {
addPass(createLoopStrengthReducePass());
if (PrintLSR)
addPass(createPrintFunctionPass(dbgs(), "\n\n*** Code after LSR ***\n"));
}
// Run GC lowering passes for builtin collectors
// TODO: add a pass insertion point here
addPass(createGCLoweringPass());
addPass(createShadowStackGCLoweringPass());
// Make sure that no unreachable blocks are instruction selected.
addPass(createUnreachableBlockEliminationPass());
// Prepare expensive constants for SelectionDAG.
if (getOptLevel() != CodeGenOpt::None && !DisableConstantHoisting)
addPass(createConstantHoistingPass());
if (getOptLevel() != CodeGenOpt::None && !DisablePartialLibcallInlining)
addPass(createPartiallyInlineLibCallsPass());
// Insert calls to mcount-like functions.
addPass(createCountingFunctionInserterPass());
}
/// Turn exception handling constructs into something the code generators can
/// handle.
void TargetPassConfig::addPassesToHandleExceptions() {
const MCAsmInfo *MCAI = TM->getMCAsmInfo();
assert(MCAI && "No MCAsmInfo");
switch (MCAI->getExceptionHandlingType()) {
case ExceptionHandling::SjLj:
// SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
// Dwarf EH prepare needs to be run after SjLj prepare. Otherwise,
// catch info can get misplaced when a selector ends up more than one block
// removed from the parent invoke(s). This could happen when a landing
// pad is shared by multiple invokes and is also a target of a normal
// edge from elsewhere.
addPass(createSjLjEHPreparePass());
LLVM_FALLTHROUGH;
case ExceptionHandling::DwarfCFI:
case ExceptionHandling::ARM:
addPass(createDwarfEHPass(TM));
break;
case ExceptionHandling::WinEH:
// We support using both GCC-style and MSVC-style exceptions on Windows, so
// add both preparation passes. Each pass will only actually run if it
// recognizes the personality function.
addPass(createWinEHPass(TM));
addPass(createDwarfEHPass(TM));
break;
case ExceptionHandling::None:
addPass(createLowerInvokePass());
// The lower invoke pass may create unreachable code. Remove it.
addPass(createUnreachableBlockEliminationPass());
break;
}
}
/// Add pass to prepare the LLVM IR for code generation. This should be done
/// before exception handling preparation passes.
void TargetPassConfig::addCodeGenPrepare() {
if (getOptLevel() != CodeGenOpt::None && !DisableCGP)
addPass(createCodeGenPreparePass(TM));
addPass(createRewriteSymbolsPass());
}
/// Add common passes that perform LLVM IR to IR transforms in preparation for
/// instruction selection.
void TargetPassConfig::addISelPrepare() {
addPreISel();
// Force codegen to run according to the callgraph.
if (TM->Options.EnableIPRA)
addPass(new DummyCGSCCPass);
// Add both the safe stack and the stack protection passes: each of them will
// only protect functions that have corresponding attributes.
addPass(createSafeStackPass(TM));
addPass(createStackProtectorPass(TM));
if (PrintISelInput)
addPass(createPrintFunctionPass(
dbgs(), "\n\n*** Final LLVM Code input to ISel ***\n"));
// All passes which modify the LLVM IR are now complete; run the verifier
// to ensure that the IR is valid.
if (!DisableVerify)
addPass(createVerifierPass());
}
/// Add the complete set of target-independent postISel code generator passes.
///
/// This can be read as the standard order of major LLVM CodeGen stages. Stages
/// with nontrivial configuration or multiple passes are broken out below in
/// add%Stage routines.
///
/// Any TargetPassConfig::addXX routine may be overriden by the Target. The
/// addPre/Post methods with empty header implementations allow injecting
/// target-specific fixups just before or after major stages. Additionally,
/// targets have the flexibility to change pass order within a stage by
/// overriding default implementation of add%Stage routines below. Each
/// technique has maintainability tradeoffs because alternate pass orders are
/// not well supported. addPre/Post works better if the target pass is easily
/// tied to a common pass. But if it has subtle dependencies on multiple passes,
/// the target should override the stage instead.
///
/// TODO: We could use a single addPre/Post(ID) hook to allow pass injection
/// before/after any target-independent pass. But it's currently overkill.
void TargetPassConfig::addMachinePasses() {
AddingMachinePasses = true;
// Insert a machine instr printer pass after the specified pass.
if (!StringRef(PrintMachineInstrs.getValue()).equals("") &&
!StringRef(PrintMachineInstrs.getValue()).equals("option-unspecified")) {
const PassRegistry *PR = PassRegistry::getPassRegistry();
const PassInfo *TPI = PR->getPassInfo(PrintMachineInstrs.getValue());
const PassInfo *IPI = PR->getPassInfo(StringRef("machineinstr-printer"));
assert (TPI && IPI && "Pass ID not registered!");
const char *TID = (const char *)(TPI->getTypeInfo());
const char *IID = (const char *)(IPI->getTypeInfo());
insertPass(TID, IID);
}
// Print the instruction selected machine code...
printAndVerify("After Instruction Selection");
if (TM->Options.EnableIPRA)
addPass(createRegUsageInfoPropPass());
// Expand pseudo-instructions emitted by ISel.
addPass(&ExpandISelPseudosID);
// Add passes that optimize machine instructions in SSA form.
if (getOptLevel() != CodeGenOpt::None) {
addMachineSSAOptimization();
} else {
// If the target requests it, assign local variables to stack slots relative
// to one another and simplify frame index references where possible.
addPass(&LocalStackSlotAllocationID, false);
}
// Run pre-ra passes.
addPreRegAlloc();
// Run register allocation and passes that are tightly coupled with it,
// including phi elimination and scheduling.
if (getOptimizeRegAlloc())
addOptimizedRegAlloc(createRegAllocPass(true));
else
addFastRegAlloc(createRegAllocPass(false));
// Run post-ra passes.
addPostRegAlloc();
// Insert prolog/epilog code. Eliminate abstract frame index references...
if (getOptLevel() != CodeGenOpt::None)
addPass(&ShrinkWrapID);
// Prolog/Epilog inserter needs a TargetMachine to instantiate. But only
// do so if it hasn't been disabled, substituted, or overridden.
if (!isPassSubstitutedOrOverridden(&PrologEpilogCodeInserterID))
addPass(createPrologEpilogInserterPass(TM));
/// Add passes that optimize machine instructions after register allocation.
if (getOptLevel() != CodeGenOpt::None)
addMachineLateOptimization();
// Expand pseudo instructions before second scheduling pass.
addPass(&ExpandPostRAPseudosID);
// Run pre-sched2 passes.
addPreSched2();
if (EnableImplicitNullChecks)
addPass(&ImplicitNullChecksID);
// Second pass scheduler.
// Let Target optionally insert this pass by itself at some other
// point.
if (getOptLevel() != CodeGenOpt::None &&
!TM->targetSchedulesPostRAScheduling()) {
if (MISchedPostRA)
addPass(&PostMachineSchedulerID);
else
addPass(&PostRASchedulerID);
}
// GC
if (addGCPasses()) {
if (PrintGCInfo)
addPass(createGCInfoPrinter(dbgs()), false, false);
}
// Basic block placement.
if (getOptLevel() != CodeGenOpt::None)
addBlockPlacement();
addPreEmitPass();
if (TM->Options.EnableIPRA)
// Collect register usage information and produce a register mask of
// clobbered registers, to be used to optimize call sites.
addPass(createRegUsageInfoCollector());
addPass(&FuncletLayoutID, false);
addPass(&StackMapLivenessID, false);
addPass(&LiveDebugValuesID, false);
// Insert before XRay Instrumentation.
addPass(&FEntryInserterID, false);
addPass(&XRayInstrumentationID, false);
addPass(&PatchableFunctionID, false);
if (EnableMachineOutliner)
PM->add(createMachineOutlinerPass());
AddingMachinePasses = false;
}
/// Add passes that optimize machine instructions in SSA form.
void TargetPassConfig::addMachineSSAOptimization() {
// Pre-ra tail duplication.
addPass(&EarlyTailDuplicateID);
// Optimize PHIs before DCE: removing dead PHI cycles may make more
// instructions dead.
addPass(&OptimizePHIsID, false);
// This pass merges large allocas. StackSlotColoring is a different pass
// which merges spill slots.
addPass(&StackColoringID, false);
// If the target requests it, assign local variables to stack slots relative
// to one another and simplify frame index references where possible.
addPass(&LocalStackSlotAllocationID, false);
// With optimization, dead code should already be eliminated. However
// there is one known exception: lowered code for arguments that are only
// used by tail calls, where the tail calls reuse the incoming stack
// arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
addPass(&DeadMachineInstructionElimID);
// Allow targets to insert passes that improve instruction level parallelism,
// like if-conversion. Such passes will typically need dominator trees and
// loop info, just like LICM and CSE below.
addILPOpts();
addPass(&MachineLICMID, false);
addPass(&MachineCSEID, false);
// Coalesce basic blocks with the same branch condition
addPass(&BranchCoalescingID);
addPass(&MachineSinkingID);
addPass(&PeepholeOptimizerID);
// Clean-up the dead code that may have been generated by peephole
// rewriting.
addPass(&DeadMachineInstructionElimID);
}
//===---------------------------------------------------------------------===//
/// Register Allocation Pass Configuration
//===---------------------------------------------------------------------===//
bool TargetPassConfig::getOptimizeRegAlloc() const {
switch (OptimizeRegAlloc) {
case cl::BOU_UNSET: return getOptLevel() != CodeGenOpt::None;
case cl::BOU_TRUE: return true;
case cl::BOU_FALSE: return false;
}
llvm_unreachable("Invalid optimize-regalloc state");
}
/// RegisterRegAlloc's global Registry tracks allocator registration.
MachinePassRegistry RegisterRegAlloc::Registry;
/// A dummy default pass factory indicates whether the register allocator is
/// overridden on the command line.
static llvm::once_flag InitializeDefaultRegisterAllocatorFlag;
static FunctionPass *useDefaultRegisterAllocator() { return nullptr; }
static RegisterRegAlloc
defaultRegAlloc("default",
"pick register allocator based on -O option",
useDefaultRegisterAllocator);
/// -regalloc=... command line option.
static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
RegisterPassParser<RegisterRegAlloc> >
RegAlloc("regalloc",
cl::init(&useDefaultRegisterAllocator),
cl::desc("Register allocator to use"));
static void initializeDefaultRegisterAllocatorOnce() {
RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
if (!Ctor) {
Ctor = RegAlloc;
RegisterRegAlloc::setDefault(RegAlloc);
}
}
/// Instantiate the default register allocator pass for this target for either
/// the optimized or unoptimized allocation path. This will be added to the pass
/// manager by addFastRegAlloc in the unoptimized case or addOptimizedRegAlloc
/// in the optimized case.
///
/// A target that uses the standard regalloc pass order for fast or optimized
/// allocation may still override this for per-target regalloc
/// selection. But -regalloc=... always takes precedence.
FunctionPass *TargetPassConfig::createTargetRegisterAllocator(bool Optimized) {
if (Optimized)
return createGreedyRegisterAllocator();
else
return createFastRegisterAllocator();
}
/// Find and instantiate the register allocation pass requested by this target
/// at the current optimization level. Different register allocators are
/// defined as separate passes because they may require different analysis.
///
/// This helper ensures that the regalloc= option is always available,
/// even for targets that override the default allocator.
///
/// FIXME: When MachinePassRegistry register pass IDs instead of function ptrs,
/// this can be folded into addPass.
FunctionPass *TargetPassConfig::createRegAllocPass(bool Optimized) {
// Initialize the global default.
llvm::call_once(InitializeDefaultRegisterAllocatorFlag,
initializeDefaultRegisterAllocatorOnce);
RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
if (Ctor != useDefaultRegisterAllocator)
return Ctor();
// With no -regalloc= override, ask the target for a regalloc pass.
return createTargetRegisterAllocator(Optimized);
}
/// Return true if the default global register allocator is in use and
/// has not be overriden on the command line with '-regalloc=...'
bool TargetPassConfig::usingDefaultRegAlloc() const {
return RegAlloc.getNumOccurrences() == 0;
}
/// Add the minimum set of target-independent passes that are required for
/// register allocation. No coalescing or scheduling.
void TargetPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
addPass(&PHIEliminationID, false);
addPass(&TwoAddressInstructionPassID, false);
if (RegAllocPass)
addPass(RegAllocPass);
}
/// Add standard target-independent passes that are tightly coupled with
/// optimized register allocation, including coalescing, machine instruction
/// scheduling, and register allocation itself.
void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
addPass(&DetectDeadLanesID, false);
addPass(&ProcessImplicitDefsID, false);
// LiveVariables currently requires pure SSA form.
//
// FIXME: Once TwoAddressInstruction pass no longer uses kill flags,
// LiveVariables can be removed completely, and LiveIntervals can be directly
// computed. (We still either need to regenerate kill flags after regalloc, or
// preferably fix the scavenger to not depend on them).
addPass(&LiveVariablesID, false);
// Edge splitting is smarter with machine loop info.
addPass(&MachineLoopInfoID, false);
addPass(&PHIEliminationID, false);
// Eventually, we want to run LiveIntervals before PHI elimination.
if (EarlyLiveIntervals)
addPass(&LiveIntervalsID, false);
addPass(&TwoAddressInstructionPassID, false);
addPass(&RegisterCoalescerID);
// The machine scheduler may accidentally create disconnected components
// when moving subregister definitions around, avoid this by splitting them to
// separate vregs before. Splitting can also improve reg. allocation quality.
addPass(&RenameIndependentSubregsID);
// PreRA instruction scheduling.
addPass(&MachineSchedulerID);
if (RegAllocPass) {
// Add the selected register allocation pass.
addPass(RegAllocPass);
// Allow targets to change the register assignments before rewriting.
addPreRewrite();
// Finally rewrite virtual registers.
addPass(&VirtRegRewriterID);
// Perform stack slot coloring and post-ra machine LICM.
//
// FIXME: Re-enable coloring with register when it's capable of adding
// kill markers.
addPass(&StackSlotColoringID);
// Run post-ra machine LICM to hoist reloads / remats.
//
// FIXME: can this move into MachineLateOptimization?
addPass(&PostRAMachineLICMID);
}
}
//===---------------------------------------------------------------------===//
/// Post RegAlloc Pass Configuration
//===---------------------------------------------------------------------===//
/// Add passes that optimize machine instructions after register allocation.
void TargetPassConfig::addMachineLateOptimization() {
// Branch folding must be run after regalloc and prolog/epilog insertion.
addPass(&BranchFolderPassID);
// Tail duplication.
// Note that duplicating tail just increases code size and degrades
// performance for targets that require Structured Control Flow.
// In addition it can also make CFG irreducible. Thus we disable it.
if (!TM->requiresStructuredCFG())
addPass(&TailDuplicateID);
// Copy propagation.
addPass(&MachineCopyPropagationID);
}
/// Add standard GC passes.
bool TargetPassConfig::addGCPasses() {
addPass(&GCMachineCodeAnalysisID, false);
return true;
}
/// Add standard basic block placement passes.
void TargetPassConfig::addBlockPlacement() {
if (addPass(&MachineBlockPlacementID)) {
// Run a separate pass to collect block placement statistics.
if (EnableBlockPlacementStats)
addPass(&MachineBlockPlacementStatsID);
}
}
//===---------------------------------------------------------------------===//
/// GlobalISel Configuration
//===---------------------------------------------------------------------===//
bool TargetPassConfig::isGlobalISelEnabled() const {
return false;
}
bool TargetPassConfig::isGlobalISelAbortEnabled() const {
return EnableGlobalISelAbort == 1;
}
bool TargetPassConfig::reportDiagnosticWhenGlobalISelFallback() const {
return EnableGlobalISelAbort == 2;
}