LLVM  6.0.0svn
CallGraph.cpp
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1 //===- CallGraph.cpp - Build a Module's call graph ------------------------===//
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 
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/IR/CallSite.h"
14 #include "llvm/IR/Module.h"
15 #include "llvm/IR/Function.h"
16 #include "llvm/IR/Intrinsics.h"
17 #include "llvm/IR/PassManager.h"
18 #include "llvm/Pass.h"
19 #include "llvm/Support/Compiler.h"
20 #include "llvm/Support/Debug.h"
22 #include <algorithm>
23 #include <cassert>
24 
25 using namespace llvm;
26 
27 //===----------------------------------------------------------------------===//
28 // Implementations of the CallGraph class methods.
29 //
30 
32  : M(M), ExternalCallingNode(getOrInsertFunction(nullptr)),
33  CallsExternalNode(llvm::make_unique<CallGraphNode>(nullptr)) {
34  // Add every function to the call graph.
35  for (Function &F : M)
36  addToCallGraph(&F);
37 }
38 
40  : M(Arg.M), FunctionMap(std::move(Arg.FunctionMap)),
41  ExternalCallingNode(Arg.ExternalCallingNode),
42  CallsExternalNode(std::move(Arg.CallsExternalNode)) {
43  Arg.FunctionMap.clear();
44  Arg.ExternalCallingNode = nullptr;
45 }
46 
48  // CallsExternalNode is not in the function map, delete it explicitly.
49  if (CallsExternalNode)
50  CallsExternalNode->allReferencesDropped();
51 
52 // Reset all node's use counts to zero before deleting them to prevent an
53 // assertion from firing.
54 #ifndef NDEBUG
55  for (auto &I : FunctionMap)
56  I.second->allReferencesDropped();
57 #endif
58 }
59 
60 void CallGraph::addToCallGraph(Function *F) {
62 
63  // If this function has external linkage or has its address taken, anything
64  // could call it.
65  if (!F->hasLocalLinkage() || F->hasAddressTaken())
66  ExternalCallingNode->addCalledFunction(CallSite(), Node);
67 
68  // If this function is not defined in this translation unit, it could call
69  // anything.
70  if (F->isDeclaration() && !F->isIntrinsic())
71  Node->addCalledFunction(CallSite(), CallsExternalNode.get());
72 
73  // Look for calls by this function.
74  for (BasicBlock &BB : *F)
75  for (Instruction &I : BB) {
76  if (auto CS = CallSite(&I)) {
77  const Function *Callee = CS.getCalledFunction();
78  if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID()))
79  // Indirect calls of intrinsics are not allowed so no need to check.
80  // We can be more precise here by using TargetArg returned by
81  // Intrinsic::isLeaf.
82  Node->addCalledFunction(CS, CallsExternalNode.get());
83  else if (!Callee->isIntrinsic())
84  Node->addCalledFunction(CS, getOrInsertFunction(Callee));
85  }
86  }
87 }
88 
89 void CallGraph::print(raw_ostream &OS) const {
90  // Print in a deterministic order by sorting CallGraphNodes by name. We do
91  // this here to avoid slowing down the non-printing fast path.
92 
94  Nodes.reserve(FunctionMap.size());
95 
96  for (const auto &I : *this)
97  Nodes.push_back(I.second.get());
98 
99  std::sort(Nodes.begin(), Nodes.end(),
100  [](CallGraphNode *LHS, CallGraphNode *RHS) {
101  if (Function *LF = LHS->getFunction())
102  if (Function *RF = RHS->getFunction())
103  return LF->getName() < RF->getName();
104 
105  return RHS->getFunction() != nullptr;
106  });
107 
108  for (CallGraphNode *CN : Nodes)
109  CN->print(OS);
110 }
111 
112 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
114 #endif
115 
116 // removeFunctionFromModule - Unlink the function from this module, returning
117 // it. Because this removes the function from the module, the call graph node
118 // is destroyed. This is only valid if the function does not call any other
119 // functions (ie, there are no edges in it's CGN). The easiest way to do this
120 // is to dropAllReferences before calling this.
121 //
123  assert(CGN->empty() && "Cannot remove function from call "
124  "graph if it references other functions!");
125  Function *F = CGN->getFunction(); // Get the function for the call graph node
126  FunctionMap.erase(F); // Remove the call graph node from the map
127 
128  M.getFunctionList().remove(F);
129  return F;
130 }
131 
132 /// spliceFunction - Replace the function represented by this node by another.
133 /// This does not rescan the body of the function, so it is suitable when
134 /// splicing the body of the old function to the new while also updating all
135 /// callers from old to new.
136 void CallGraph::spliceFunction(const Function *From, const Function *To) {
137  assert(FunctionMap.count(From) && "No CallGraphNode for function!");
138  assert(!FunctionMap.count(To) &&
139  "Pointing CallGraphNode at a function that already exists");
140  FunctionMapTy::iterator I = FunctionMap.find(From);
141  I->second->F = const_cast<Function*>(To);
142  FunctionMap[To] = std::move(I->second);
143  FunctionMap.erase(I);
144 }
145 
146 // getOrInsertFunction - This method is identical to calling operator[], but
147 // it will insert a new CallGraphNode for the specified function if one does
148 // not already exist.
150  auto &CGN = FunctionMap[F];
151  if (CGN)
152  return CGN.get();
153 
154  assert((!F || F->getParent() == &M) && "Function not in current module!");
155  CGN = llvm::make_unique<CallGraphNode>(const_cast<Function *>(F));
156  return CGN.get();
157 }
158 
159 //===----------------------------------------------------------------------===//
160 // Implementations of the CallGraphNode class methods.
161 //
162 
164  if (Function *F = getFunction())
165  OS << "Call graph node for function: '" << F->getName() << "'";
166  else
167  OS << "Call graph node <<null function>>";
168 
169  OS << "<<" << this << ">> #uses=" << getNumReferences() << '\n';
170 
171  for (const auto &I : *this) {
172  OS << " CS<" << I.first << "> calls ";
173  if (Function *FI = I.second->getFunction())
174  OS << "function '" << FI->getName() <<"'\n";
175  else
176  OS << "external node\n";
177  }
178  OS << '\n';
179 }
180 
181 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
183 #endif
184 
185 /// removeCallEdgeFor - This method removes the edge in the node for the
186 /// specified call site. Note that this method takes linear time, so it
187 /// should be used sparingly.
189  for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
190  assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
191  if (I->first == CS.getInstruction()) {
192  I->second->DropRef();
193  *I = CalledFunctions.back();
194  CalledFunctions.pop_back();
195  return;
196  }
197  }
198 }
199 
200 // removeAnyCallEdgeTo - This method removes any call edges from this node to
201 // the specified callee function. This takes more time to execute than
202 // removeCallEdgeTo, so it should not be used unless necessary.
204  for (unsigned i = 0, e = CalledFunctions.size(); i != e; ++i)
205  if (CalledFunctions[i].second == Callee) {
206  Callee->DropRef();
207  CalledFunctions[i] = CalledFunctions.back();
208  CalledFunctions.pop_back();
209  --i; --e;
210  }
211 }
212 
213 /// removeOneAbstractEdgeTo - Remove one edge associated with a null callsite
214 /// from this node to the specified callee function.
216  for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
217  assert(I != CalledFunctions.end() && "Cannot find callee to remove!");
218  CallRecord &CR = *I;
219  if (CR.second == Callee && CR.first == nullptr) {
220  Callee->DropRef();
221  *I = CalledFunctions.back();
222  CalledFunctions.pop_back();
223  return;
224  }
225  }
226 }
227 
228 /// replaceCallEdge - This method replaces the edge in the node for the
229 /// specified call site with a new one. Note that this method takes linear
230 /// time, so it should be used sparingly.
232  CallSite NewCS, CallGraphNode *NewNode){
233  for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
234  assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
235  if (I->first == CS.getInstruction()) {
236  I->second->DropRef();
237  I->first = NewCS.getInstruction();
238  I->second = NewNode;
239  NewNode->AddRef();
240  return;
241  }
242  }
243 }
244 
245 // Provide an explicit template instantiation for the static ID.
246 AnalysisKey CallGraphAnalysis::Key;
247 
249  ModuleAnalysisManager &AM) {
250  AM.getResult<CallGraphAnalysis>(M).print(OS);
251  return PreservedAnalyses::all();
252 }
253 
254 //===----------------------------------------------------------------------===//
255 // Out-of-line definitions of CallGraphAnalysis class members.
256 //
257 
258 //===----------------------------------------------------------------------===//
259 // Implementations of the CallGraphWrapperPass class methods.
260 //
261 
264 }
265 
267 
269  AU.setPreservesAll();
270 }
271 
273  // All the real work is done in the constructor for the CallGraph.
274  G.reset(new CallGraph(M));
275  return false;
276 }
277 
278 INITIALIZE_PASS(CallGraphWrapperPass, "basiccg", "CallGraph Construction",
279  false, true)
280 
281 char CallGraphWrapperPass::ID = 0;
282 
283 void CallGraphWrapperPass::releaseMemory() { G.reset(); }
284 
286  if (!G) {
287  OS << "No call graph has been built!\n";
288  return;
289  }
290 
291  // Just delegate.
292  G->print(OS);
293 }
294 
295 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
297 void CallGraphWrapperPass::dump() const { print(dbgs(), nullptr); }
298 #endif
299 
300 namespace {
301 
302 struct CallGraphPrinterLegacyPass : public ModulePass {
303  static char ID; // Pass ID, replacement for typeid
304 
305  CallGraphPrinterLegacyPass() : ModulePass(ID) {
307  }
308 
309  void getAnalysisUsage(AnalysisUsage &AU) const override {
310  AU.setPreservesAll();
312  }
313 
314  bool runOnModule(Module &M) override {
315  getAnalysis<CallGraphWrapperPass>().print(errs(), &M);
316  return false;
317  }
318 };
319 
320 } // end anonymous namespace
321 
323 
324 INITIALIZE_PASS_BEGIN(CallGraphPrinterLegacyPass, "print-callgraph",
325  "Print a call graph", true, true)
327 INITIALIZE_PASS_END(CallGraphPrinterLegacyPass, "print-callgraph",
328  "Print a call graph", true, true)
bool isIntrinsic() const
isIntrinsic - Returns true if the function&#39;s name starts with "llvm.".
Definition: Function.h:180
raw_ostream & errs()
This returns a reference to a raw_ostream for standard error.
bool hasLocalLinkage() const
Definition: GlobalValue.h:416
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
void Print(const Unit &v, const char *PrintAfter)
Definition: FuzzerUtil.cpp:34
PassT::Result & getResult(IRUnitT &IR, ExtraArgTs... ExtraArgs)
Get the result of an analysis pass for a given IR unit.
Definition: PassManager.h:687
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
#define LLVM_DUMP_METHOD
Mark debug helper function definitions like dump() that should not be stripped from debug builds...
Definition: Compiler.h:449
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:63
unsigned second
F(f)
std::enable_if<!std::is_array< T >::value, std::unique_ptr< T > >::type make_unique(Args &&... args)
Constructs a new T() with the given args and returns a unique_ptr<T> which owns the object...
Definition: STLExtras.h:941
bool runOnModule(Module &M) override
runOnModule - Virtual method overriden by subclasses to process the module being operated on...
Definition: CallGraph.cpp:272
void reserve(size_type N)
Definition: SmallVector.h:380
A node in the call graph for a module.
Definition: CallGraph.h:165
void removeOneAbstractEdgeTo(CallGraphNode *Callee)
Removes one edge associated with a null callsite from this node to the specified callee function...
Definition: CallGraph.cpp:215
void addCalledFunction(CallSite CS, CallGraphNode *M)
Adds a function to the list of functions called by this one.
Definition: CallGraph.h:233
print callgraph
Definition: CallGraph.cpp:327
#define INITIALIZE_PASS_DEPENDENCY(depName)
Definition: PassSupport.h:51
Definition: BitVector.h:920
void replaceCallEdge(CallSite CS, CallSite NewCS, CallGraphNode *NewNode)
Replaces the edge in the node for the specified call site with a new one.
Definition: CallGraph.cpp:231
void print(raw_ostream &OS) const
Definition: CallGraph.cpp:163
ModulePass(char &pid)
Definition: Pass.h:227
Function * removeFunctionFromModule(CallGraphNode *CGN)
Unlink the function from this module, returning it.
Definition: CallGraph.cpp:122
InstrTy * getInstruction() const
Definition: CallSite.h:92
void dump() const
Print out this call graph node.
Definition: CallGraph.cpp:182
This file provides interfaces used to build and manipulate a call graph, which is a very useful tool ...
amdgpu Simplify well known AMD library false Value * Callee
void releaseMemory() override
releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memo...
void initializeCallGraphPrinterLegacyPassPass(PassRegistry &)
void removeAnyCallEdgeTo(CallGraphNode *Callee)
Removes all call edges from this node to the specified callee function.
Definition: CallGraph.cpp:203
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:153
The ModulePass which wraps up a CallGraph and the logic to build it.
Definition: CallGraph.h:324
bool isLeaf(ID id)
Returns true if the intrinsic is a leaf, i.e.
Definition: Function.cpp:958
const FunctionListType & getFunctionList() const
Get the Module&#39;s list of functions (constant).
Definition: Module.h:507
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
void initializeCallGraphWrapperPassPass(PassRegistry &)
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:116
Represent the analysis usage information of a pass.
CallGraph(Module &M)
Definition: CallGraph.cpp:31
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
Definition: PassManager.h:159
INITIALIZE_PASS_END(RegBankSelect, DEBUG_TYPE, "Assign register bank of generic virtual registers", false, false) RegBankSelect
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:34
Function * getFunction() const
Returns the function that this call graph node represents.
Definition: CallGraph.h:188
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
Module.h This file contains the declarations for the Module class.
bool empty() const
Definition: CallGraph.h:194
PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM)
Definition: CallGraph.cpp:248
Intrinsic::ID getIntrinsicID() const LLVM_READONLY
getIntrinsicID - This method returns the ID number of the specified function, or Intrinsic::not_intri...
Definition: Function.h:175
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
INITIALIZE_PASS_BEGIN(CallGraphPrinterLegacyPass, "print-callgraph", "Print a call graph", true, true) INITIALIZE_PASS_END(CallGraphPrinterLegacyPass
void setPreservesAll()
Set by analyses that do not transform their input at all.
amdgpu Simplify well known AMD library false Value Value * Arg
An analysis pass to compute the CallGraph for a Module.
Definition: CallGraph.h:292
pointer remove(iterator &IT)
Definition: ilist.h:264
The basic data container for the call graph of a Module of IR.
Definition: CallGraph.h:74
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:120
print Print a call true
Definition: CallGraph.cpp:327
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:218
std::pair< WeakTrackingVH, CallGraphNode * > CallRecord
A pair of the calling instruction (a call or invoke) and the call graph node being called...
Definition: CallGraph.h:169
#define I(x, y, z)
Definition: MD5.cpp:58
ModulePass class - This class is used to implement unstructured interprocedural optimizations and ana...
Definition: Pass.h:225
AnalysisUsage & addRequiredTransitive()
bool isDeclaration() const
Return true if the primary definition of this global value is outside of the current translation unit...
Definition: Globals.cpp:200
bool hasAddressTaken(const User **=nullptr) const
hasAddressTaken - returns true if there are any uses of this function other than direct calls or invo...
Definition: Function.cpp:1208
const Function * getFunction() const
Definition: Function.h:134
print Print a call graph
Definition: CallGraph.cpp:327
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:545
CallGraphNode * getOrInsertFunction(const Function *F)
Similar to operator[], but this will insert a new CallGraphNode for F if one does not already exist...
Definition: CallGraph.cpp:149
void removeCallEdgeFor(CallSite CS)
Removes the edge in the node for the specified call site.
Definition: CallGraph.cpp:188
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
A container for analyses that lazily runs them and caches their results.
void sort(Policy policy, RandomAccessIterator Start, RandomAccessIterator End, const Comparator &Comp=Comparator())
Definition: Parallel.h:199
void dump() const
Definition: CallGraph.cpp:113
This header defines various interfaces for pass management in LLVM.
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - This function should be overriden by passes that need analysis information to do t...
Definition: CallGraph.cpp:268
void print(raw_ostream &o, const Module *) const override
print - Print out the internal state of the pass.
Definition: CallGraph.cpp:285
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:70
void print(raw_ostream &OS) const
Definition: CallGraph.cpp:89