llvm/lib/CodeGen/FuncletLayout.cpp
Chandler Carruth 6b547686c5 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-19 08:50:56 +00:00

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