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Diffstat (limited to 'llvm/lib/CodeGen/CFIInstrInserter.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/CFIInstrInserter.cpp | 319 |
1 files changed, 0 insertions, 319 deletions
diff --git a/llvm/lib/CodeGen/CFIInstrInserter.cpp b/llvm/lib/CodeGen/CFIInstrInserter.cpp deleted file mode 100644 index 5464ee443e0..00000000000 --- a/llvm/lib/CodeGen/CFIInstrInserter.cpp +++ /dev/null @@ -1,319 +0,0 @@ -//===------ CFIInstrInserter.cpp - Insert additional CFI instructions -----===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -/// \file This pass verifies incoming and outgoing CFA information of basic -/// blocks. CFA information is information about offset and register set by CFI -/// directives, valid at the start and end of a basic block. This pass checks -/// that outgoing information of predecessors matches incoming information of -/// their successors. Then it checks if blocks have correct CFA calculation rule -/// set and inserts additional CFI instruction at their beginnings if they -/// don't. CFI instructions are inserted if basic blocks have incorrect offset -/// or register set by previous blocks, as a result of a non-linear layout of -/// blocks in a function. -//===----------------------------------------------------------------------===// - -#include "llvm/CodeGen/MachineFunctionPass.h" -#include "llvm/CodeGen/MachineInstrBuilder.h" -#include "llvm/CodeGen/MachineModuleInfo.h" -#include "llvm/CodeGen/Passes.h" -#include "llvm/CodeGen/TargetFrameLowering.h" -#include "llvm/CodeGen/TargetInstrInfo.h" -#include "llvm/Target/TargetMachine.h" -#include "llvm/Target/TargetSubtargetInfo.h" -using namespace llvm; - -namespace { -class CFIInstrInserter : public MachineFunctionPass { - public: - static char ID; - - CFIInstrInserter() : MachineFunctionPass(ID) { - initializeCFIInstrInserterPass(*PassRegistry::getPassRegistry()); - } - - void getAnalysisUsage(AnalysisUsage &AU) const override { - AU.setPreservesAll(); - MachineFunctionPass::getAnalysisUsage(AU); - } - - bool runOnMachineFunction(MachineFunction &MF) override { - - if (!MF.getMMI().hasDebugInfo() && - !MF.getFunction()->needsUnwindTableEntry()) - return false; - - MBBVector.resize(MF.getNumBlockIDs()); - calculateCFAInfo(MF); -#ifndef NDEBUG - unsigned ErrorNum = verify(MF); - if (ErrorNum) - report_fatal_error("Found " + Twine(ErrorNum) + - " in/out CFI information errors."); -#endif - bool insertedCFI = insertCFIInstrs(MF); - MBBVector.clear(); - return insertedCFI; - } - - private: - struct MBBCFAInfo { - MachineBasicBlock *MBB; - /// Value of cfa offset valid at basic block entry. - int IncomingCFAOffset = -1; - /// Value of cfa offset valid at basic block exit. - int OutgoingCFAOffset = -1; - /// Value of cfa register valid at basic block entry. - unsigned IncomingCFARegister = 0; - /// Value of cfa register valid at basic block exit. - unsigned OutgoingCFARegister = 0; - /// If in/out cfa offset and register values for this block have already - /// been set or not. - bool Processed = false; - }; - - /// Contains cfa offset and register values valid at entry and exit of basic - /// blocks. - SmallVector<struct MBBCFAInfo, 4> MBBVector; - - /// Calculate cfa offset and register values valid at entry and exit for all - /// basic blocks in a function. - void calculateCFAInfo(MachineFunction &MF); - /// Calculate cfa offset and register values valid at basic block exit by - /// checking the block for CFI instructions. Block's incoming CFA info remains - /// the same. - void calculateOutgoingCFAInfo(struct MBBCFAInfo &MBBInfo); - /// Update in/out cfa offset and register values for successors of the basic - /// block. - void updateSuccCFAInfo(struct MBBCFAInfo &MBBInfo); - - /// Check if incoming CFA information of a basic block matches outgoing CFA - /// information of the previous block. If it doesn't, insert CFI instruction - /// at the beginning of the block that corrects the CFA calculation rule for - /// that block. - bool insertCFIInstrs(MachineFunction &MF); - /// Return the cfa offset value that should be set at the beginning of a MBB - /// if needed. The negated value is needed when creating CFI instructions that - /// set absolute offset. - int getCorrectCFAOffset(MachineBasicBlock *MBB) { - return -MBBVector[MBB->getNumber()].IncomingCFAOffset; - } - - void report(const char *msg, MachineBasicBlock &MBB); - /// Go through each MBB in a function and check that outgoing offset and - /// register of its predecessors match incoming offset and register of that - /// MBB, as well as that incoming offset and register of its successors match - /// outgoing offset and register of the MBB. - unsigned verify(MachineFunction &MF); -}; -} - -char CFIInstrInserter::ID = 0; -INITIALIZE_PASS(CFIInstrInserter, "cfi-instr-inserter", - "Check CFA info and insert CFI instructions if needed", false, - false) -FunctionPass *llvm::createCFIInstrInserter() { return new CFIInstrInserter(); } - -void CFIInstrInserter::calculateCFAInfo(MachineFunction &MF) { - // Initial CFA offset value i.e. the one valid at the beginning of the - // function. - int InitialOffset = - MF.getSubtarget().getFrameLowering()->getInitialCFAOffset(MF); - // Initial CFA register value i.e. the one valid at the beginning of the - // function. - unsigned InitialRegister = - MF.getSubtarget().getFrameLowering()->getInitialCFARegister(MF); - - // Initialize MBBMap. - for (MachineBasicBlock &MBB : MF) { - struct MBBCFAInfo MBBInfo; - MBBInfo.MBB = &MBB; - MBBInfo.IncomingCFAOffset = InitialOffset; - MBBInfo.OutgoingCFAOffset = InitialOffset; - MBBInfo.IncomingCFARegister = InitialRegister; - MBBInfo.OutgoingCFARegister = InitialRegister; - MBBVector[MBB.getNumber()] = MBBInfo; - } - - // Set in/out cfa info for all blocks in the function. This traversal is based - // on the assumption that the first block in the function is the entry block - // i.e. that it has initial cfa offset and register values as incoming CFA - // information. - for (MachineBasicBlock &MBB : MF) { - if (MBBVector[MBB.getNumber()].Processed) continue; - calculateOutgoingCFAInfo(MBBVector[MBB.getNumber()]); - updateSuccCFAInfo(MBBVector[MBB.getNumber()]); - } -} - -void CFIInstrInserter::calculateOutgoingCFAInfo(struct MBBCFAInfo &MBBInfo) { - // Outgoing cfa offset set by the block. - int SetOffset = MBBInfo.IncomingCFAOffset; - // Outgoing cfa register set by the block. - unsigned SetRegister = MBBInfo.IncomingCFARegister; - const std::vector<MCCFIInstruction> &Instrs = - MBBInfo.MBB->getParent()->getFrameInstructions(); - - // Determine cfa offset and register set by the block. - for (MachineInstr &MI : - make_range(MBBInfo.MBB->instr_begin(), MBBInfo.MBB->instr_end())) { - if (MI.isCFIInstruction()) { - unsigned CFIIndex = MI.getOperand(0).getCFIIndex(); - const MCCFIInstruction &CFI = Instrs[CFIIndex]; - if (CFI.getOperation() == MCCFIInstruction::OpDefCfaRegister) { - SetRegister = CFI.getRegister(); - } else if (CFI.getOperation() == MCCFIInstruction::OpDefCfaOffset) { - SetOffset = CFI.getOffset(); - } else if (CFI.getOperation() == MCCFIInstruction::OpAdjustCfaOffset) { - SetOffset += CFI.getOffset(); - } else if (CFI.getOperation() == MCCFIInstruction::OpDefCfa) { - SetRegister = CFI.getRegister(); - SetOffset = CFI.getOffset(); - } - } - } - - MBBInfo.Processed = true; - - // Update outgoing CFA info. - MBBInfo.OutgoingCFAOffset = SetOffset; - MBBInfo.OutgoingCFARegister = SetRegister; -} - -void CFIInstrInserter::updateSuccCFAInfo(struct MBBCFAInfo &MBBInfo) { - - for (MachineBasicBlock *Succ : MBBInfo.MBB->successors()) { - struct MBBCFAInfo &SuccInfo = MBBVector[Succ->getNumber()]; - if (SuccInfo.Processed) continue; - SuccInfo.IncomingCFAOffset = MBBInfo.OutgoingCFAOffset; - SuccInfo.IncomingCFARegister = MBBInfo.OutgoingCFARegister; - calculateOutgoingCFAInfo(SuccInfo); - updateSuccCFAInfo(SuccInfo); - } -} - -bool CFIInstrInserter::insertCFIInstrs(MachineFunction &MF) { - - const struct MBBCFAInfo *PrevMBBInfo = &MBBVector[MF.front().getNumber()]; - const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo(); - bool InsertedCFIInstr = false; - - for (MachineBasicBlock &MBB : MF) { - // Skip the first MBB in a function - if (MBB.getNumber() == MF.front().getNumber()) continue; - - const struct MBBCFAInfo& MBBInfo = MBBVector[MBB.getNumber()]; - auto MBBI = MBBInfo.MBB->begin(); - DebugLoc DL = MBBInfo.MBB->findDebugLoc(MBBI); - - if (PrevMBBInfo->OutgoingCFAOffset != MBBInfo.IncomingCFAOffset) { - // If both outgoing offset and register of a previous block don't match - // incoming offset and register of this block, add a def_cfa instruction - // with the correct offset and register for this block. - if (PrevMBBInfo->OutgoingCFARegister != MBBInfo.IncomingCFARegister) { - unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::createDefCfa( - nullptr, MBBInfo.IncomingCFARegister, getCorrectCFAOffset(&MBB))); - BuildMI(*MBBInfo.MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION)) - .addCFIIndex(CFIIndex); - // If outgoing offset of a previous block doesn't match incoming offset - // of this block, add a def_cfa_offset instruction with the correct - // offset for this block. - } else { - unsigned CFIIndex = - MF.addFrameInst(MCCFIInstruction::createDefCfaOffset( - nullptr, getCorrectCFAOffset(&MBB))); - BuildMI(*MBBInfo.MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION)) - .addCFIIndex(CFIIndex); - } - InsertedCFIInstr = true; - // If outgoing register of a previous block doesn't match incoming - // register of this block, add a def_cfa_register instruction with the - // correct register for this block. - } else if (PrevMBBInfo->OutgoingCFARegister != MBBInfo.IncomingCFARegister) { - unsigned CFIIndex = - MF.addFrameInst(MCCFIInstruction::createDefCfaRegister( - nullptr, MBBInfo.IncomingCFARegister)); - BuildMI(*MBBInfo.MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION)) - .addCFIIndex(CFIIndex); - InsertedCFIInstr = true; - } - PrevMBBInfo = &MBBInfo; - } - return InsertedCFIInstr; -} - -void CFIInstrInserter::report(const char *msg, MachineBasicBlock &MBB) { - errs() << '\n'; - errs() << "*** " << msg << " ***\n" - << "- function: " << MBB.getParent()->getName() << "\n"; - errs() << "- basic block: BB#" << MBB.getNumber() << ' ' << MBB.getName() - << " (" << (const void *)&MBB << ')'; - errs() << '\n'; -} - -unsigned CFIInstrInserter::verify(MachineFunction &MF) { - unsigned ErrorNum = 0; - for (MachineBasicBlock &CurrMBB : MF) { - const struct MBBCFAInfo& CurrMBBInfo = MBBVector[CurrMBB.getNumber()]; - for (MachineBasicBlock *Pred : CurrMBB.predecessors()) { - const struct MBBCFAInfo& PredMBBInfo = MBBVector[Pred->getNumber()]; - // Check that outgoing offset values of predecessors match the incoming - // offset value of CurrMBB - if (PredMBBInfo.OutgoingCFAOffset != CurrMBBInfo.IncomingCFAOffset) { - report("The outgoing offset of a predecessor is inconsistent.", - CurrMBB); - errs() << "Predecessor BB#" << Pred->getNumber() - << " has outgoing offset (" << PredMBBInfo.OutgoingCFAOffset - << "), while BB#" << CurrMBB.getNumber() - << " has incoming offset (" << CurrMBBInfo.IncomingCFAOffset - << ").\n"; - ErrorNum++; - } - // Check that outgoing register values of predecessors match the incoming - // register value of CurrMBB - if (PredMBBInfo.OutgoingCFARegister != CurrMBBInfo.IncomingCFARegister) { - report("The outgoing register of a predecessor is inconsistent.", - CurrMBB); - errs() << "Predecessor BB#" << Pred->getNumber() - << " has outgoing register (" << PredMBBInfo.OutgoingCFARegister - << "), while BB#" << CurrMBB.getNumber() - << " has incoming register (" << CurrMBBInfo.IncomingCFARegister - << ").\n"; - ErrorNum++; - } - } - - for (MachineBasicBlock *Succ : CurrMBB.successors()) { - const struct MBBCFAInfo& SuccMBBInfo = MBBVector[Succ->getNumber()]; - // Check that incoming offset values of successors match the outgoing - // offset value of CurrMBB - if (SuccMBBInfo.IncomingCFAOffset != CurrMBBInfo.OutgoingCFAOffset) { - report("The incoming offset of a successor is inconsistent.", CurrMBB); - errs() << "Successor BB#" << Succ->getNumber() - << " has incoming offset (" << SuccMBBInfo.IncomingCFAOffset - << "), while BB#" << CurrMBB.getNumber() - << " has outgoing offset (" << CurrMBBInfo.OutgoingCFAOffset - << ").\n"; - ErrorNum++; - } - // Check that incoming register values of successors match the outgoing - // register value of CurrMBB - if (SuccMBBInfo.IncomingCFARegister != CurrMBBInfo.OutgoingCFARegister) { - report("The incoming register of a successor is inconsistent.", - CurrMBB); - errs() << "Successor BB#" << Succ->getNumber() - << " has incoming register (" << SuccMBBInfo.IncomingCFARegister - << "), while BB#" << CurrMBB.getNumber() - << " has outgoing register (" << CurrMBBInfo.OutgoingCFARegister - << ").\n"; - ErrorNum++; - } - } - } - return ErrorNum; -} |
