| //===- LiveDebugValues.cpp - Tracking Debug Value MIs ---------------------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "LiveDebugValues.h" |
| |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/CodeGen/MachineDominators.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/MachineFunctionPass.h" |
| #include "llvm/CodeGen/Passes.h" |
| #include "llvm/CodeGen/TargetPassConfig.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/Pass.h" |
| #include "llvm/PassRegistry.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Target/TargetMachine.h" |
| |
| /// \file LiveDebugValues.cpp |
| /// |
| /// The LiveDebugValues pass extends the range of variable locations |
| /// (specified by DBG_VALUE instructions) from single blocks to successors |
| /// and any other code locations where the variable location is valid. |
| /// There are currently two implementations: the "VarLoc" implementation |
| /// explicitly tracks the location of a variable, while the "InstrRef" |
| /// implementation tracks the values defined by instructions through locations. |
| /// |
| /// This file implements neither; it merely registers the pass, allows the |
| /// user to pick which implementation will be used to propagate variable |
| /// locations. |
| |
| #define DEBUG_TYPE "livedebugvalues" |
| |
| using namespace llvm; |
| |
| static cl::opt<bool> |
| ForceInstrRefLDV("force-instr-ref-livedebugvalues", cl::Hidden, |
| cl::desc("Use instruction-ref based LiveDebugValues with " |
| "normal DBG_VALUE inputs"), |
| cl::init(false)); |
| |
| static cl::opt<cl::boolOrDefault> ValueTrackingVariableLocations( |
| "experimental-debug-variable-locations", |
| cl::desc("Use experimental new value-tracking variable locations")); |
| |
| // Options to prevent pathological compile-time behavior. If InputBBLimit and |
| // InputDbgValueLimit are both exceeded, range extension is disabled. |
| static cl::opt<unsigned> InputBBLimit( |
| "livedebugvalues-input-bb-limit", |
| cl::desc("Maximum input basic blocks before DBG_VALUE limit applies"), |
| cl::init(10000), cl::Hidden); |
| static cl::opt<unsigned> InputDbgValueLimit( |
| "livedebugvalues-input-dbg-value-limit", |
| cl::desc( |
| "Maximum input DBG_VALUE insts supported by debug range extension"), |
| cl::init(50000), cl::Hidden); |
| |
| namespace { |
| /// Generic LiveDebugValues pass. Calls through to VarLocBasedLDV or |
| /// InstrRefBasedLDV to perform location propagation, via the LDVImpl |
| /// base class. |
| class LiveDebugValues : public MachineFunctionPass { |
| public: |
| static char ID; |
| |
| LiveDebugValues(); |
| ~LiveDebugValues() = default; |
| |
| /// Calculate the liveness information for the given machine function. |
| bool runOnMachineFunction(MachineFunction &MF) override; |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| AU.setPreservesCFG(); |
| MachineFunctionPass::getAnalysisUsage(AU); |
| } |
| |
| private: |
| std::unique_ptr<LDVImpl> InstrRefImpl; |
| std::unique_ptr<LDVImpl> VarLocImpl; |
| TargetPassConfig *TPC; |
| MachineDominatorTree MDT; |
| }; |
| } // namespace |
| |
| char LiveDebugValues::ID = 0; |
| |
| char &llvm::LiveDebugValuesID = LiveDebugValues::ID; |
| |
| INITIALIZE_PASS(LiveDebugValues, DEBUG_TYPE, "Live DEBUG_VALUE analysis", false, |
| false) |
| |
| /// Default construct and initialize the pass. |
| LiveDebugValues::LiveDebugValues() : MachineFunctionPass(ID) { |
| initializeLiveDebugValuesPass(*PassRegistry::getPassRegistry()); |
| InstrRefImpl = |
| std::unique_ptr<LDVImpl>(llvm::makeInstrRefBasedLiveDebugValues()); |
| VarLocImpl = std::unique_ptr<LDVImpl>(llvm::makeVarLocBasedLiveDebugValues()); |
| } |
| |
| bool LiveDebugValues::runOnMachineFunction(MachineFunction &MF) { |
| // Except for Wasm, all targets should be only using physical register at this |
| // point. Wasm only use virtual registers throught its pipeline, but its |
| // virtual registers don't participate in this LiveDebugValues analysis; only |
| // its target indices do. |
| assert(MF.getTarget().getTargetTriple().isWasm() || |
| MF.getProperties().hasProperty( |
| MachineFunctionProperties::Property::NoVRegs)); |
| |
| bool InstrRefBased = MF.useDebugInstrRef(); |
| // Allow the user to force selection of InstrRef LDV. |
| InstrRefBased |= ForceInstrRefLDV; |
| |
| TPC = getAnalysisIfAvailable<TargetPassConfig>(); |
| LDVImpl *TheImpl = &*VarLocImpl; |
| |
| MachineDominatorTree *DomTree = nullptr; |
| if (InstrRefBased) { |
| DomTree = &MDT; |
| MDT.calculate(MF); |
| TheImpl = &*InstrRefImpl; |
| } |
| |
| return TheImpl->ExtendRanges(MF, DomTree, TPC, InputBBLimit, |
| InputDbgValueLimit); |
| } |
| |
| bool llvm::debuginfoShouldUseDebugInstrRef(const Triple &T) { |
| // Enable by default on x86_64, disable if explicitly turned off on cmdline. |
| if (T.getArch() == llvm::Triple::x86_64 && |
| ValueTrackingVariableLocations != cl::boolOrDefault::BOU_FALSE) |
| return true; |
| |
| // Enable if explicitly requested on command line. |
| return ValueTrackingVariableLocations == cl::boolOrDefault::BOU_TRUE; |
| } |