LLVM  14.0.0git
LiveDebugValues.cpp
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1 //===- LiveDebugValues.cpp - Tracking Debug Value MIs ---------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "LiveDebugValues.h"
10 
14 #include "llvm/CodeGen/Passes.h"
15 #include "llvm/InitializePasses.h"
16 #include "llvm/Pass.h"
19 
20 /// \file LiveDebugValues.cpp
21 ///
22 /// The LiveDebugValues pass extends the range of variable locations
23 /// (specified by DBG_VALUE instructions) from single blocks to successors
24 /// and any other code locations where the variable location is valid.
25 /// There are currently two implementations: the "VarLoc" implementation
26 /// explicitly tracks the location of a variable, while the "InstrRef"
27 /// implementation tracks the values defined by instructions through locations.
28 ///
29 /// This file implements neither; it merely registers the pass, allows the
30 /// user to pick which implementation will be used to propagate variable
31 /// locations.
32 
33 #define DEBUG_TYPE "livedebugvalues"
34 
35 using namespace llvm;
36 
37 static cl::opt<bool>
38  ForceInstrRefLDV("force-instr-ref-livedebugvalues", cl::Hidden,
39  cl::desc("Use instruction-ref based LiveDebugValues with "
40  "normal DBG_VALUE inputs"),
41  cl::init(false));
42 
43 // Options to prevent pathological compile-time behavior. If InputBBLimit and
44 // InputDbgValueLimit are both exceeded, range extension is disabled.
46  "livedebugvalues-input-bb-limit",
47  cl::desc("Maximum input basic blocks before DBG_VALUE limit applies"),
48  cl::init(10000), cl::Hidden);
50  "livedebugvalues-input-dbg-value-limit",
51  cl::desc(
52  "Maximum input DBG_VALUE insts supported by debug range extension"),
53  cl::init(50000), cl::Hidden);
54 
55 /// Generic LiveDebugValues pass. Calls through to VarLocBasedLDV or
56 /// InstrRefBasedLDV to perform location propagation, via the LDVImpl
57 /// base class.
59 public:
60  static char ID;
61 
64 
65  /// Calculate the liveness information for the given machine function.
66  bool runOnMachineFunction(MachineFunction &MF) override;
67 
71  }
72 
73  void getAnalysisUsage(AnalysisUsage &AU) const override {
74  AU.setPreservesCFG();
76  }
77 
78 private:
79  std::unique_ptr<LDVImpl> InstrRefImpl;
80  std::unique_ptr<LDVImpl> VarLocImpl;
81  TargetPassConfig *TPC;
83 };
84 
85 char LiveDebugValues::ID = 0;
86 
88 
89 INITIALIZE_PASS(LiveDebugValues, DEBUG_TYPE, "Live DEBUG_VALUE analysis", false,
90  false)
91 
92 /// Default construct and initialize the pass.
95  InstrRefImpl =
96  std::unique_ptr<LDVImpl>(llvm::makeInstrRefBasedLiveDebugValues());
97  VarLocImpl = std::unique_ptr<LDVImpl>(llvm::makeVarLocBasedLiveDebugValues());
98 }
99 
101  bool InstrRefBased = MF.useDebugInstrRef();
102  // Allow the user to force selection of InstrRef LDV.
103  InstrRefBased |= ForceInstrRefLDV;
104 
105  TPC = getAnalysisIfAvailable<TargetPassConfig>();
106  LDVImpl *TheImpl = &*VarLocImpl;
107 
108  MachineDominatorTree *DomTree = nullptr;
109  if (InstrRefBased) {
110  DomTree = &MDT;
111  MDT.calculate(MF);
112  TheImpl = &*InstrRefImpl;
113  }
114 
115  return TheImpl->ExtendRanges(MF, DomTree, TPC, InputBBLimit,
117 }
llvm
This file implements support for optimizing divisions by a constant.
Definition: AllocatorList.h:23
llvm::SharedLiveDebugValues::LDVImpl
Definition: LiveDebugValues.h:25
llvm::initializeLiveDebugValuesPass
void initializeLiveDebugValuesPass(PassRegistry &)
Pass.h
llvm::MachineFunction::useDebugInstrRef
bool useDebugInstrRef() const
Returns true if the function's variable locations should be tracked with instruction referencing.
Definition: MachineFunction.cpp:1224
llvm::MachineFunctionPass
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
Definition: MachineFunctionPass.h:30
MachineBasicBlock.h
llvm::cl::Hidden
@ Hidden
Definition: CommandLine.h:143
llvm::MachineFunctionProperties
Properties which a MachineFunction may have at a given point in time.
Definition: MachineFunction.h:111
llvm::SharedLiveDebugValues::LDVImpl::ExtendRanges
virtual bool ExtendRanges(MachineFunction &MF, MachineDominatorTree *DomTree, TargetPassConfig *TPC, unsigned InputBBLimit, unsigned InputDbgValLimit)=0
llvm::MachineFunctionPass::getAnalysisUsage
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
Definition: MachineFunctionPass.cpp:102
LiveDebugValues
Definition: InstrRefBasedImpl.h:33
DEBUG_TYPE
#define DEBUG_TYPE
Definition: LiveDebugValues.cpp:33
CommandLine.h
llvm::LiveDebugValuesID
char & LiveDebugValuesID
LiveDebugValues pass.
Definition: LiveDebugValues.cpp:87
TargetMachine.h
llvm::PassRegistry::getPassRegistry
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
Definition: PassRegistry.cpp:31
llvm::AnalysisUsage
Represent the analysis usage information of a pass.
Definition: PassAnalysisSupport.h:47
llvm::MachineFunctionProperties::set
MachineFunctionProperties & set(Property P)
Definition: MachineFunction.h:173
LiveDebugValues::~LiveDebugValues
~LiveDebugValues()
Definition: LiveDebugValues.cpp:63
InputDbgValueLimit
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)
ForceInstrRefLDV
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))
llvm::MachineFunctionProperties::Property::NoVRegs
@ NoVRegs
Passes.h
llvm::TargetPassConfig
Target-Independent Code Generator Pass Configuration Options.
Definition: TargetPassConfig.h:84
llvm::cl::opt< bool >
LiveDebugValues::getRequiredProperties
MachineFunctionProperties getRequiredProperties() const override
Definition: LiveDebugValues.cpp:68
llvm::cl::init
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:441
MachineFunctionPass.h
LiveDebugValues::runOnMachineFunction
bool runOnMachineFunction(MachineFunction &MF) override
Calculate the liveness information for the given machine function.
Definition: LiveDebugValues.cpp:100
llvm::makeInstrRefBasedLiveDebugValues
LDVImpl * makeInstrRefBasedLiveDebugValues()
Definition: InstrRefBasedImpl.cpp:2920
llvm::MachineFunction
Definition: MachineFunction.h:234
llvm::AnalysisUsage::setPreservesCFG
void setPreservesCFG()
This function should be called by the pass, iff they do not:
Definition: Pass.cpp:253
MachineFrameInfo.h
LiveDebugValues::ID
static char ID
Definition: LiveDebugValues.cpp:60
InputBBLimit
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)
LiveDebugValues.h
INITIALIZE_PASS
INITIALIZE_PASS(LiveDebugValues, DEBUG_TYPE, "Live DEBUG_VALUE analysis", false, false) LiveDebugValues
Default construct and initialize the pass.
Definition: LiveDebugValues.cpp:89
llvm::MachineDominatorTree::calculate
void calculate(MachineFunction &F)
Definition: MachineDominators.cpp:57
llvm::cl::desc
Definition: CommandLine.h:412
llvm::MachineDominatorTree
DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to compute a normal dominat...
Definition: MachineDominators.h:45
llvm::makeVarLocBasedLiveDebugValues
LDVImpl * makeVarLocBasedLiveDebugValues()
Definition: VarLocBasedImpl.cpp:2306
InitializePasses.h
LiveDebugValues::getAnalysisUsage
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
Definition: LiveDebugValues.cpp:73
llvm::Intrinsic::ID
unsigned ID
Definition: TargetTransformInfo.h:37