forked from OSchip/llvm-project
				
			
		
			
				
	
	
		
			63 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			63 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
//===-- FuncletLayout.cpp - Contiguously lay out funclets -----------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements basic block placement transformations which result in
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// funclets being contiguous.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/Analysis.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/InitializePasses.h"
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using namespace llvm;
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#define DEBUG_TYPE "funclet-layout"
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namespace {
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class FuncletLayout : public MachineFunctionPass {
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public:
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  static char ID; // Pass identification, replacement for typeid
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  FuncletLayout() : MachineFunctionPass(ID) {
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    initializeFuncletLayoutPass(*PassRegistry::getPassRegistry());
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  }
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  bool runOnMachineFunction(MachineFunction &F) override;
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  MachineFunctionProperties getRequiredProperties() const override {
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    return MachineFunctionProperties().set(
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        MachineFunctionProperties::Property::NoVRegs);
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  }
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};
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}
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char FuncletLayout::ID = 0;
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char &llvm::FuncletLayoutID = FuncletLayout::ID;
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INITIALIZE_PASS(FuncletLayout, DEBUG_TYPE,
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                "Contiguously Lay Out Funclets", false, false)
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bool FuncletLayout::runOnMachineFunction(MachineFunction &F) {
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  // Even though this gets information from getEHScopeMembership(), this pass is
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  // only necessary for funclet-based EH personalities, in which these EH scopes
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  // are outlined at the end.
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  DenseMap<const MachineBasicBlock *, int> FuncletMembership =
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      getEHScopeMembership(F);
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  if (FuncletMembership.empty())
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    return false;
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  F.sort([&](MachineBasicBlock &X, MachineBasicBlock &Y) {
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    auto FuncletX = FuncletMembership.find(&X);
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    auto FuncletY = FuncletMembership.find(&Y);
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    assert(FuncletX != FuncletMembership.end());
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    assert(FuncletY != FuncletMembership.end());
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    return FuncletX->second < FuncletY->second;
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  });
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  // Conservatively assume we changed something.
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  return true;
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}
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