summaryrefslogtreecommitdiffstats
path: root/gnu/llvm/lib/CodeGen/CFIInstrInserter.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'gnu/llvm/lib/CodeGen/CFIInstrInserter.cpp')
-rw-r--r--gnu/llvm/lib/CodeGen/CFIInstrInserter.cpp331
1 files changed, 0 insertions, 331 deletions
diff --git a/gnu/llvm/lib/CodeGen/CFIInstrInserter.cpp b/gnu/llvm/lib/CodeGen/CFIInstrInserter.cpp
deleted file mode 100644
index c4799855a2b..00000000000
--- a/gnu/llvm/lib/CodeGen/CFIInstrInserter.cpp
+++ /dev/null
@@ -1,331 +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/ADT/DepthFirstIterator.h"
-#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/CodeGen/TargetSubtargetInfo.h"
-#include "llvm/Target/TargetMachine.h"
-using namespace llvm;
-
-static cl::opt<bool> VerifyCFI("verify-cfiinstrs",
- cl::desc("Verify Call Frame Information instructions"),
- cl::init(false),
- cl::Hidden);
-
-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);
-
- if (VerifyCFI) {
- if (unsigned ErrorNum = verify(MF))
- report_fatal_error("Found " + Twine(ErrorNum) +
- " in/out CFI information errors.");
- }
- 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.
- std::vector<MBBCFAInfo> 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(MBBCFAInfo &MBBInfo);
- /// Update in/out cfa offset and register values for successors of the basic
- /// block.
- void updateSuccCFAInfo(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 MBBCFAInfo &Pred, const MBBCFAInfo &Succ);
- /// 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);
-};
-} // namespace
-
-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) {
- 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;
- updateSuccCFAInfo(MBBVector[MBB.getNumber()]);
- }
-}
-
-void CFIInstrInserter::calculateOutgoingCFAInfo(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 : *MBBInfo.MBB) {
- if (MI.isCFIInstruction()) {
- unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
- const MCCFIInstruction &CFI = Instrs[CFIIndex];
- switch (CFI.getOperation()) {
- case MCCFIInstruction::OpDefCfaRegister:
- SetRegister = CFI.getRegister();
- break;
- case MCCFIInstruction::OpDefCfaOffset:
- SetOffset = CFI.getOffset();
- break;
- case MCCFIInstruction::OpAdjustCfaOffset:
- SetOffset += CFI.getOffset();
- break;
- case MCCFIInstruction::OpDefCfa:
- SetRegister = CFI.getRegister();
- SetOffset = CFI.getOffset();
- break;
- case MCCFIInstruction::OpRememberState:
- // TODO: Add support for handling cfi_remember_state.
-#ifndef NDEBUG
- report_fatal_error(
- "Support for cfi_remember_state not implemented! Value of CFA "
- "may be incorrect!\n");
-#endif
- break;
- case MCCFIInstruction::OpRestoreState:
- // TODO: Add support for handling cfi_restore_state.
-#ifndef NDEBUG
- report_fatal_error(
- "Support for cfi_restore_state not implemented! Value of CFA may "
- "be incorrect!\n");
-#endif
- break;
- // Other CFI directives do not affect CFA value.
- case MCCFIInstruction::OpSameValue:
- case MCCFIInstruction::OpOffset:
- case MCCFIInstruction::OpRelOffset:
- case MCCFIInstruction::OpEscape:
- case MCCFIInstruction::OpRestore:
- case MCCFIInstruction::OpUndefined:
- case MCCFIInstruction::OpRegister:
- case MCCFIInstruction::OpWindowSave:
- case MCCFIInstruction::OpNegateRAState:
- case MCCFIInstruction::OpGnuArgsSize:
- break;
- }
- }
- }
-
- MBBInfo.Processed = true;
-
- // Update outgoing CFA info.
- MBBInfo.OutgoingCFAOffset = SetOffset;
- MBBInfo.OutgoingCFARegister = SetRegister;
-}
-
-void CFIInstrInserter::updateSuccCFAInfo(MBBCFAInfo &MBBInfo) {
- SmallVector<MachineBasicBlock *, 4> Stack;
- Stack.push_back(MBBInfo.MBB);
-
- do {
- MachineBasicBlock *Current = Stack.pop_back_val();
- MBBCFAInfo &CurrentInfo = MBBVector[Current->getNumber()];
- if (CurrentInfo.Processed)
- continue;
-
- calculateOutgoingCFAInfo(CurrentInfo);
- for (auto *Succ : CurrentInfo.MBB->successors()) {
- MBBCFAInfo &SuccInfo = MBBVector[Succ->getNumber()];
- if (!SuccInfo.Processed) {
- SuccInfo.IncomingCFAOffset = CurrentInfo.OutgoingCFAOffset;
- SuccInfo.IncomingCFARegister = CurrentInfo.OutgoingCFARegister;
- Stack.push_back(Succ);
- }
- }
- } while (!Stack.empty());
-}
-
-bool CFIInstrInserter::insertCFIInstrs(MachineFunction &MF) {
- const 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 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 MBBCFAInfo &Pred, const MBBCFAInfo &Succ) {
- errs() << "*** Inconsistent CFA register and/or offset between pred and succ "
- "***\n";
- errs() << "Pred: " << Pred.MBB->getName() << " #" << Pred.MBB->getNumber()
- << " in " << Pred.MBB->getParent()->getName()
- << " outgoing CFA Reg:" << Pred.OutgoingCFARegister << "\n";
- errs() << "Pred: " << Pred.MBB->getName() << " #" << Pred.MBB->getNumber()
- << " in " << Pred.MBB->getParent()->getName()
- << " outgoing CFA Offset:" << Pred.OutgoingCFAOffset << "\n";
- errs() << "Succ: " << Succ.MBB->getName() << " #" << Succ.MBB->getNumber()
- << " incoming CFA Reg:" << Succ.IncomingCFARegister << "\n";
- errs() << "Succ: " << Succ.MBB->getName() << " #" << Succ.MBB->getNumber()
- << " incoming CFA Offset:" << Succ.IncomingCFAOffset << "\n";
-}
-
-unsigned CFIInstrInserter::verify(MachineFunction &MF) {
- unsigned ErrorNum = 0;
- for (auto *CurrMBB : depth_first(&MF)) {
- const MBBCFAInfo &CurrMBBInfo = MBBVector[CurrMBB->getNumber()];
- for (MachineBasicBlock *Succ : CurrMBB->successors()) {
- const MBBCFAInfo &SuccMBBInfo = MBBVector[Succ->getNumber()];
- // Check that incoming offset and register values of successors match the
- // outgoing offset and register values of CurrMBB
- if (SuccMBBInfo.IncomingCFAOffset != CurrMBBInfo.OutgoingCFAOffset ||
- SuccMBBInfo.IncomingCFARegister != CurrMBBInfo.OutgoingCFARegister) {
- // Inconsistent offsets/registers are ok for 'noreturn' blocks because
- // we don't generate epilogues inside such blocks.
- if (SuccMBBInfo.MBB->succ_empty() && !SuccMBBInfo.MBB->isReturnBlock())
- continue;
- report(CurrMBBInfo, SuccMBBInfo);
- ErrorNum++;
- }
- }
- }
- return ErrorNum;
-}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.