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//===-- llvm/CodeGen/FinalizeISel.cpp ---------------------------*- C++ -*-===//
//
// 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 pass expands Pseudo-instructions produced by ISel, fixes register
/// reservations and may do machine frame information adjustments.
/// The pseudo instructions are used to allow the expansion to contain control
/// flow, such as a conditional move implemented with a conditional branch and a
/// phi, or an atomic operation implemented with a loop.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/InitializePasses.h"
using namespace llvm;
#define DEBUG_TYPE "finalize-isel"
namespace {
class FinalizeISel : public MachineFunctionPass {
public:
static char ID; // Pass identification, replacement for typeid
FinalizeISel() : MachineFunctionPass(ID) {}
private:
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
MachineFunctionPass::getAnalysisUsage(AU);
}
};
} // end anonymous namespace
char FinalizeISel::ID = 0;
char &llvm::FinalizeISelID = FinalizeISel::ID;
INITIALIZE_PASS(FinalizeISel, DEBUG_TYPE,
"Finalize ISel and expand pseudo-instructions", false, false)
bool FinalizeISel::runOnMachineFunction(MachineFunction &MF) {
bool Changed = false;
const TargetLowering *TLI = MF.getSubtarget().getTargetLowering();
// Iterate through each instruction in the function, looking for pseudos.
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
MachineBasicBlock *MBB = &*I;
for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
MBBI != MBBE; ) {
MachineInstr &MI = *MBBI++;
// If MI is a pseudo, expand it.
if (MI.usesCustomInsertionHook()) {
Changed = true;
MachineBasicBlock *NewMBB = TLI->EmitInstrWithCustomInserter(MI, MBB);
// The expansion may involve new basic blocks.
if (NewMBB != MBB) {
MBB = NewMBB;
I = NewMBB->getIterator();
MBBI = NewMBB->begin();
MBBE = NewMBB->end();
}
}
}
}
TLI->finalizeLowering(MF);
return Changed;
}
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