BPFCodeGenPassBuilder.cpp

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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
 
#include "BPF.h"
#include "BPFAsmPrinter.h"
#include "BPFSubtarget.h"
#include "BPFTargetMachine.h"
#include "llvm/CodeGen/AtomicExpand.h"
#include "llvm/IR/PassInstrumentation.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Passes/CodeGenPassBuilder.h"
#include "llvm/Passes/PassBuilder.h"
#include "llvm/Support/Error.h"
#include "llvm/Target/CGPassBuilderOption.h"
#include "llvm/Transforms/Scalar/SimplifyCFG.h"
#include "llvm/Transforms/Utils/SimplifyCFGOptions.h"
 
using namespace llvm;
 
extern cl::opt<bool> DisableMIPeephole;
 
namespace {
 
class BPFCodeGenPassBuilder : public CodeGenPassBuilder {
  using Base = CodeGenPassBuilder;
 
  BPFTargetMachine &getTM() const {
    return static_cast<BPFTargetMachine &>(TM);
  }
 
public:
  explicit BPFCodeGenPassBuilder(BPFTargetMachine &TM,
                                 const CGPassBuilderOption &Opts,
                                 PassInstrumentationCallbacks *PIC)
      : CodeGenPassBuilder(TM, Opts, PIC) {}
 
  void addIRPasses(PassManagerWrapper &PMW) override;
  Error addInstSelector(PassManagerWrapper &PMW) override;
  void addMachineSSAOptimization(PassManagerWrapper &PMW) override;
  void addPreEmitPass(PassManagerWrapper &PMW) override;
  void addAsmPrinterBegin(PassManagerWrapper &PMW) override;
  void addAsmPrinter(PassManagerWrapper &PMW) override;
  void addAsmPrinterEnd(PassManagerWrapper &PMW) override;
};
 
void BPFCodeGenPassBuilder::addIRPasses(PassManagerWrapper &PMW) {
  addFunctionPass(AtomicExpandPass(TM), PMW);
  flushFPMsToMPM(PMW);
  addModulePass(BPFCheckAndAdjustIRPass(), PMW);
 
  Base::addIRPasses(PMW);
}
 
Error BPFCodeGenPassBuilder::addInstSelector(PassManagerWrapper &PMW) {
  addMachineFunctionPass(BPFISelDAGToDAGPass(getTM()), PMW);
  return Error::success();
}
 
void BPFCodeGenPassBuilder::addMachineSSAOptimization(PassManagerWrapper &PMW) {
  addMachineFunctionPass(BPFMISimplifyPatchablePass(), PMW);
 
  Base::addMachineSSAOptimization(PMW);
 
  const BPFSubtarget *Subtarget = getTM().getSubtargetImpl();
  if (!DisableMIPeephole) {
    if (Subtarget->getHasAlu32())
      addMachineFunctionPass(BPFMIPeepholePass(), PMW);
  }
}
 
void BPFCodeGenPassBuilder::addPreEmitPass(PassManagerWrapper &PMW) {
  addMachineFunctionPass(BPFMIPreEmitCheckingPass(), PMW);
  if (!DisableMIPeephole) {
    addMachineFunctionPass(BPFMIExpandStackArgPseudosPass(), PMW);
    addMachineFunctionPass(BPFMIPreEmitPeepholePass(), PMW);
  }
}
 
void BPFCodeGenPassBuilder::addAsmPrinterBegin(PassManagerWrapper &PMW) {
  addModulePass(BPFAsmPrinterBeginPass(), PMW, /*Force=*/true);
}
 
void BPFCodeGenPassBuilder::addAsmPrinter(PassManagerWrapper &PMW) {
  addMachineFunctionPass(BPFAsmPrinterPass(), PMW);
}
 
void BPFCodeGenPassBuilder::addAsmPrinterEnd(PassManagerWrapper &PMW) {
  addModulePass(BPFAsmPrinterEndPass(), PMW);
}
 
} // namespace
 
static Expected<bool> parseBPFPreserveStaticOffsetOptions(StringRef Params) {
  return PassBuilder::parseSinglePassOption(Params, "allow-partial",
                                            "BPFPreserveStaticOffsetPass");
}
 
void BPFTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
#define GET_PASS_REGISTRY "BPFPassRegistry.def"
#include "llvm/Passes/TargetPassRegistry.inc"
 
  PB.registerPipelineStartEPCallback(
      [=](ModulePassManager &MPM, OptimizationLevel) {
        FunctionPassManager FPM;
        FPM.addPass(BPFPreserveStaticOffsetPass(true));
        FPM.addPass(BPFAbstractMemberAccessPass(this));
        FPM.addPass(BPFPreserveDITypePass());
        FPM.addPass(BPFIRPeepholePass());
        MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
      });
  PB.registerPeepholeEPCallback([=](FunctionPassManager &FPM,
                                    OptimizationLevel Level) {
    FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().hoistCommonInsts(true)));
    FPM.addPass(BPFASpaceCastSimplifyPass());
  });
  PB.registerScalarOptimizerLateEPCallback(
      [=](FunctionPassManager &FPM, OptimizationLevel Level) {
        // Run this after loop unrolling but before
        // SimplifyCFGPass(... .sinkCommonInsts(true))
        FPM.addPass(BPFPreserveStaticOffsetPass(false));
      });
  PB.registerPipelineEarlySimplificationEPCallback(
      [=](ModulePassManager &MPM, OptimizationLevel, ThinOrFullLTOPhase) {
        MPM.addPass(BPFAdjustOptPass());
      });
}
 
Error BPFTargetMachine::buildCodeGenPipeline(
    ModulePassManager &MPM, ModuleAnalysisManager &MAM, raw_pwrite_stream &Out,
    raw_pwrite_stream *DwoOut, CodeGenFileType FileType,
    const CGPassBuilderOption &Opt, MCContext &Ctx,
    PassInstrumentationCallbacks *PIC) {
  auto CGPB = BPFCodeGenPassBuilder(*this, Opt, PIC);
  return CGPB.buildPipeline(MPM, MAM, Out, DwoOut, FileType, Ctx);
}