LLVM  8.0.0svn
LowerInvoke.cpp
Go to the documentation of this file.
1 //===- LowerInvoke.cpp - Eliminate Invoke instructions --------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This transformation is designed for use by code generators which do not yet
11 // support stack unwinding. This pass converts 'invoke' instructions to 'call'
12 // instructions, so that any exception-handling 'landingpad' blocks become dead
13 // code (which can be removed by running the '-simplifycfg' pass afterwards).
14 //
15 //===----------------------------------------------------------------------===//
16 
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/IR/Instructions.h"
21 #include "llvm/IR/LLVMContext.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/Pass.h"
24 #include "llvm/Transforms/Utils.h"
25 using namespace llvm;
26 
27 #define DEBUG_TYPE "lowerinvoke"
28 
29 STATISTIC(NumInvokes, "Number of invokes replaced");
30 
31 namespace {
32  class LowerInvokeLegacyPass : public FunctionPass {
33  public:
34  static char ID; // Pass identification, replacement for typeid
35  explicit LowerInvokeLegacyPass() : FunctionPass(ID) {
37  }
38  bool runOnFunction(Function &F) override;
39  };
40 }
41 
43 INITIALIZE_PASS(LowerInvokeLegacyPass, "lowerinvoke",
44  "Lower invoke and unwind, for unwindless code generators",
45  false, false)
46 
47 static bool runImpl(Function &F) {
48  bool Changed = false;
49  for (BasicBlock &BB : F)
50  if (InvokeInst *II = dyn_cast<InvokeInst>(BB.getTerminator())) {
51  SmallVector<Value *, 16> CallArgs(II->arg_begin(), II->arg_end());
53  II->getOperandBundlesAsDefs(OpBundles);
54  // Insert a normal call instruction...
55  CallInst *NewCall =
56  CallInst::Create(II->getCalledValue(), CallArgs, OpBundles, "", II);
57  NewCall->takeName(II);
58  NewCall->setCallingConv(II->getCallingConv());
59  NewCall->setAttributes(II->getAttributes());
60  NewCall->setDebugLoc(II->getDebugLoc());
61  II->replaceAllUsesWith(NewCall);
62 
63  // Insert an unconditional branch to the normal destination.
64  BranchInst::Create(II->getNormalDest(), II);
65 
66  // Remove any PHI node entries from the exception destination.
67  II->getUnwindDest()->removePredecessor(&BB);
68 
69  // Remove the invoke instruction now.
70  BB.getInstList().erase(II);
71 
72  ++NumInvokes;
73  Changed = true;
74  }
75  return Changed;
76 }
77 
79  return runImpl(F);
80 }
81 
82 namespace llvm {
84 
85 // Public Interface To the LowerInvoke pass.
86 FunctionPass *createLowerInvokePass() { return new LowerInvokeLegacyPass(); }
87 
90  bool Changed = runImpl(F);
91  if (!Changed)
92  return PreservedAnalyses::all();
93 
94  return PreservedAnalyses::none();
95 }
96 }
static bool runImpl(Function &F, TargetLibraryInfo &TLI, DominatorTree &DT)
This is the entry point for all transforms.
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
This class represents lattice values for constants.
Definition: AllocatorList.h:24
static CallInst * Create(FunctionType *Ty, Value *F, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
INITIALIZE_PASS(LowerInvokeLegacyPass, "lowerinvoke", "Lower invoke and unwind, for unwindless code generators", false, false) static bool runImpl(Function &F)
Definition: LowerInvoke.cpp:43
This class represents a function call, abstracting a target machine&#39;s calling convention.
char & LowerInvokePassID
Definition: LowerInvoke.cpp:83
STATISTIC(NumFunctions, "Total number of functions")
F(f)
FunctionPass * createLowerInvokePass()
Definition: LowerInvoke.cpp:86
void initializeLowerInvokeLegacyPassPass(PassRegistry &)
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:291
static PreservedAnalyses none()
Convenience factory function for the empty preserved set.
Definition: PassManager.h:157
static bool runOnFunction(Function &F, bool PostInlining)
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:154
void setDebugLoc(DebugLoc Loc)
Set the debug location information for this instruction.
Definition: Instruction.h:308
LLVM Basic Block Representation.
Definition: BasicBlock.h:58
void setCallingConv(CallingConv::ID CC)
Definition: InstrTypes.h:1229
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:285
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
Definition: PassManager.h:160
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM)
Definition: LowerInvoke.cpp:88
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
Module.h This file contains the declarations for the Module class.
static BranchInst * Create(BasicBlock *IfTrue, Instruction *InsertBefore=nullptr)
void setAttributes(AttributeList A)
Set the parameter attributes for this call.
Definition: InstrTypes.h:1248
Invoke instruction.
A container for analyses that lazily runs them and caches their results.