1 //===- TraceValues.cpp - Value Tracing for debugging -------------*- C++ -*--=//
3 // Support for inserting LLVM code to print values at basic block and function
6 //===----------------------------------------------------------------------===//
8 #include "llvm/Transforms/Instrumentation.h"
9 #include "llvm/Constants.h"
10 #include "llvm/DerivedTypes.h"
11 #include "llvm/iMemory.h"
12 #include "llvm/iTerminators.h"
13 #include "llvm/iOther.h"
14 #include "llvm/Module.h"
15 #include "llvm/Pass.h"
16 #include "llvm/Assembly/Writer.h"
17 #include "Support/CommandLine.h"
18 #include "Support/StringExtras.h"
25 DisablePtrHashing("tracedisablehashdisable", cl::Hidden,
26 cl::desc("Disable pointer hashing in the -trace or -tracem "
29 static cl::list<string>
30 TraceFuncNames("tracefunc", cl::desc("Only trace specific functions in the "
31 "-trace or -tracem passes"),
32 cl::value_desc("function"), cl::Hidden);
34 static void TraceValuesAtBBExit(BasicBlock *BB,
35 Function *Printf, Function* HashPtrToSeqNum,
36 vector<Instruction*> *valuesStoredInFunction);
38 // We trace a particular function if no functions to trace were specified
39 // or if the function is in the specified list.
42 TraceThisFunction(Function &F)
44 if (TraceFuncNames.empty()) return true;
46 return std::find(TraceFuncNames.begin(), TraceFuncNames.end(), F.getName())
47 != TraceFuncNames.end();
52 struct ExternalFuncs {
53 Function *PrintfFunc, *HashPtrFunc, *ReleasePtrFunc;
54 Function *RecordPtrFunc, *PushOnEntryFunc, *ReleaseOnReturnFunc;
55 void doInitialization(Module &M); // Add prototypes for external functions
58 class InsertTraceCode : public FunctionPass {
60 ExternalFuncs externalFuncs;
63 // Add a prototype for runtime functions not already in the program.
65 bool doInitialization(Module &M);
67 //--------------------------------------------------------------------------
68 // Function InsertCodeToTraceValues
70 // Inserts tracing code for all live values at basic block and/or function
71 // exits as specified by `traceBasicBlockExits' and `traceFunctionExits'.
73 bool doit(Function *M);
75 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) = 0;
77 // runOnFunction - This method does the work.
79 bool runOnFunction(Function &F);
81 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
86 struct FunctionTracer : public InsertTraceCode {
87 // Ignore basic blocks here...
88 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {}
91 struct BasicBlockTracer : public InsertTraceCode {
92 // Trace basic blocks here...
93 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {
94 TraceValuesAtBBExit(BB, externalFuncs.PrintfFunc,
95 externalFuncs.HashPtrFunc, &VI);
99 // Register the passes...
100 RegisterOpt<FunctionTracer> X("tracem","Insert Function trace code only");
101 RegisterOpt<BasicBlockTracer> Y("trace","Insert BB and Function trace code");
102 } // end anonymous namespace
105 Pass *createTraceValuesPassForFunction() { // Just trace functions
106 return new FunctionTracer();
109 Pass *createTraceValuesPassForBasicBlocks() { // Trace BB's and functions
110 return new BasicBlockTracer();
114 // Add a prototype for external functions used by the tracing code.
116 void ExternalFuncs::doInitialization(Module &M) {
117 const Type *SBP = PointerType::get(Type::SByteTy);
118 const FunctionType *MTy =
119 FunctionType::get(Type::IntTy, vector<const Type*>(1, SBP), true);
120 PrintfFunc = M.getOrInsertFunction("printf", MTy);
123 const FunctionType *hashFuncTy =
124 FunctionType::get(Type::UIntTy, vector<const Type*>(1, SBP), false);
125 HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", hashFuncTy);
128 const FunctionType *voidSBPFuncTy =
129 FunctionType::get(Type::VoidTy, vector<const Type*>(1, SBP), false);
131 ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum", voidSBPFuncTy);
132 RecordPtrFunc = M.getOrInsertFunction("RecordPointer", voidSBPFuncTy);
134 const FunctionType *voidvoidFuncTy =
135 FunctionType::get(Type::VoidTy, vector<const Type*>(), false);
137 PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", voidvoidFuncTy);
138 ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
143 // Add a prototype for external functions used by the tracing code.
145 bool InsertTraceCode::doInitialization(Module &M) {
146 externalFuncs.doInitialization(M);
151 static inline GlobalVariable *getStringRef(Module *M, const string &str) {
152 // Create a constant internal string reference...
153 Constant *Init = ConstantArray::get(str);
155 // Create the global variable and record it in the module
156 // The GV will be renamed to a unique name if needed.
157 GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
158 GlobalValue::InternalLinkage, Init,
160 M->getGlobalList().push_back(GV);
166 // Check if this instruction has any uses outside its basic block,
167 // or if it used by either a Call or Return instruction.
169 static inline bool LiveAtBBExit(const Instruction* I) {
170 const BasicBlock *BB = I->getParent();
171 for (Value::use_const_iterator U = I->use_begin(); U != I->use_end(); ++U)
172 if (const Instruction *UI = dyn_cast<Instruction>(*U))
173 if (UI->getParent() != BB || isa<ReturnInst>(UI))
180 static inline bool TraceThisOpCode(unsigned opCode) {
181 // Explicitly test for opCodes *not* to trace so that any new opcodes will
182 // be traced by default (VoidTy's are already excluded)
184 return (opCode < Instruction::OtherOpsBegin &&
185 opCode != Instruction::Alloca &&
186 opCode != Instruction::PHINode &&
187 opCode != Instruction::Cast);
191 static bool ShouldTraceValue(const Instruction *I) {
193 I->getType() != Type::VoidTy && LiveAtBBExit(I) &&
194 TraceThisOpCode(I->getOpcode());
197 static string getPrintfCodeFor(const Value *V) {
198 if (V == 0) return "";
199 if (V->getType()->isFloatingPoint())
201 else if (V->getType() == Type::LabelTy)
203 else if (isa<PointerType>(V->getType()))
204 return DisablePtrHashing ? "0x%p" : "%d";
205 else if (V->getType()->isIntegral())
208 assert(0 && "Illegal value to print out...");
213 static void InsertPrintInst(Value *V, BasicBlock *BB, Instruction *InsertBefore,
215 Function *Printf, Function* HashPtrToSeqNum) {
216 // Escape Message by replacing all % characters with %% chars.
218 std::swap(Tmp, Message);
219 string::iterator I = std::find(Tmp.begin(), Tmp.end(), '%');
220 while (I != Tmp.end()) {
221 Message.append(Tmp.begin(), I);
223 ++I; // Make sure to erase the % as well...
224 Tmp.erase(Tmp.begin(), I);
225 I = std::find(Tmp.begin(), Tmp.end(), '%');
228 Module *Mod = BB->getParent()->getParent();
230 // Turn the marker string into a global variable...
231 GlobalVariable *fmtVal = getStringRef(Mod, Message+getPrintfCodeFor(V)+"\n");
233 // Turn the format string into an sbyte *
234 Constant *GEP =ConstantExpr::getGetElementPtr(ConstantPointerRef::get(fmtVal),
235 vector<Constant*>(2,Constant::getNullValue(Type::LongTy)));
237 // Insert a call to the hash function if this is a pointer value
238 if (V && isa<PointerType>(V->getType()) && !DisablePtrHashing) {
239 const Type *SBP = PointerType::get(Type::SByteTy);
240 if (V->getType() != SBP) // Cast pointer to be sbyte*
241 V = new CastInst(V, SBP, "Hash_cast", InsertBefore);
243 vector<Value*> HashArgs(1, V);
244 V = new CallInst(HashPtrToSeqNum, HashArgs, "ptrSeqNum", InsertBefore);
247 // Insert the first print instruction to print the string flag:
248 vector<Value*> PrintArgs;
249 PrintArgs.push_back(GEP);
250 if (V) PrintArgs.push_back(V);
251 new CallInst(Printf, PrintArgs, "trace", InsertBefore);
255 static void InsertVerbosePrintInst(Value *V, BasicBlock *BB,
256 Instruction *InsertBefore,
257 const string &Message, Function *Printf,
258 Function* HashPtrToSeqNum) {
259 std::ostringstream OutStr;
260 if (V) WriteAsOperand(OutStr, V);
261 InsertPrintInst(V, BB, InsertBefore, Message+OutStr.str()+" = ",
262 Printf, HashPtrToSeqNum);
266 InsertReleaseInst(Value *V, BasicBlock *BB,
267 Instruction *InsertBefore,
268 Function* ReleasePtrFunc) {
270 const Type *SBP = PointerType::get(Type::SByteTy);
271 if (V->getType() != SBP) // Cast pointer to be sbyte*
272 V = new CastInst(V, SBP, "RPSN_cast", InsertBefore);
274 vector<Value*> releaseArgs(1, V);
275 new CallInst(ReleasePtrFunc, releaseArgs, "", InsertBefore);
279 InsertRecordInst(Value *V, BasicBlock *BB,
280 Instruction *InsertBefore,
281 Function* RecordPtrFunc) {
282 const Type *SBP = PointerType::get(Type::SByteTy);
283 if (V->getType() != SBP) // Cast pointer to be sbyte*
284 V = new CastInst(V, SBP, "RP_cast", InsertBefore);
286 vector<Value*> releaseArgs(1, V);
287 new CallInst(RecordPtrFunc, releaseArgs, "", InsertBefore);
290 // Look for alloca and free instructions. These are the ptrs to release.
291 // Release the free'd pointers immediately. Record the alloca'd pointers
292 // to be released on return from the current function.
295 ReleasePtrSeqNumbers(BasicBlock *BB,
296 ExternalFuncs& externalFuncs) {
298 for (BasicBlock::iterator II=BB->begin(), IE = BB->end(); II != IE; ++II)
299 if (FreeInst *FI = dyn_cast<FreeInst>(II))
300 InsertReleaseInst(FI->getOperand(0), BB, FI,externalFuncs.ReleasePtrFunc);
301 else if (AllocaInst *AI = dyn_cast<AllocaInst>(II))
302 InsertRecordInst(AI, BB, AI->getNext(), externalFuncs.RecordPtrFunc);
306 // Insert print instructions at the end of basic block BB for each value
307 // computed in BB that is live at the end of BB,
308 // or that is stored to memory in BB.
309 // If the value is stored to memory, we load it back before printing it
310 // We also return all such loaded values in the vector valuesStoredInFunction
311 // for printing at the exit from the function. (Note that in each invocation
312 // of the function, this will only get the last value stored for each static
313 // store instruction).
315 static void TraceValuesAtBBExit(BasicBlock *BB,
316 Function *Printf, Function* HashPtrToSeqNum,
317 vector<Instruction*> *valuesStoredInFunction) {
318 // Get an iterator to point to the insertion location, which is
319 // just before the terminator instruction.
321 TerminatorInst *InsertPos = BB->getTerminator();
323 std::ostringstream OutStr;
324 WriteAsOperand(OutStr, BB, false);
325 InsertPrintInst(0, BB, InsertPos, "LEAVING BB:" + OutStr.str(),
326 Printf, HashPtrToSeqNum);
328 // Insert a print instruction for each instruction preceding InsertPos.
329 // The print instructions must go before InsertPos, so we use the
330 // instruction *preceding* InsertPos to check when to terminate the loop.
332 for (BasicBlock::iterator II = BB->begin(); &*II != InsertPos; ++II) {
333 if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
334 assert(valuesStoredInFunction &&
335 "Should not be printing a store instruction at function exit");
336 LoadInst *LI = new LoadInst(SI->getPointerOperand(), "reload." +
337 SI->getPointerOperand()->getName(),
339 valuesStoredInFunction->push_back(LI);
341 if (ShouldTraceValue(II))
342 InsertVerbosePrintInst(II, BB, InsertPos, " ", Printf, HashPtrToSeqNum);
346 static inline void InsertCodeToShowFunctionEntry(Function &F, Function *Printf,
347 Function* HashPtrToSeqNum){
348 // Get an iterator to point to the insertion location
349 BasicBlock &BB = F.getEntryNode();
350 Instruction *InsertPos = BB.begin();
352 std::ostringstream OutStr;
353 WriteAsOperand(OutStr, &F);
354 InsertPrintInst(0, &BB, InsertPos, "ENTERING FUNCTION: " + OutStr.str(),
355 Printf, HashPtrToSeqNum);
357 // Now print all the incoming arguments
359 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++ArgNo){
360 InsertVerbosePrintInst(I, &BB, InsertPos,
361 " Arg #" + utostr(ArgNo) + ": ", Printf,
367 static inline void InsertCodeToShowFunctionExit(BasicBlock *BB,
369 Function* HashPtrToSeqNum) {
370 // Get an iterator to point to the insertion location
371 ReturnInst *Ret = cast<ReturnInst>(BB->getTerminator());
373 std::ostringstream OutStr;
374 WriteAsOperand(OutStr, BB->getParent(), true);
375 InsertPrintInst(0, BB, Ret, "LEAVING FUNCTION: " + OutStr.str(),
376 Printf, HashPtrToSeqNum);
378 // print the return value, if any
379 if (BB->getParent()->getReturnType() != Type::VoidTy)
380 InsertPrintInst(Ret->getReturnValue(), BB, Ret, " Returning: ",
381 Printf, HashPtrToSeqNum);
385 bool InsertTraceCode::runOnFunction(Function &F) {
386 if (!TraceThisFunction(F))
389 vector<Instruction*> valuesStoredInFunction;
390 vector<BasicBlock*> exitBlocks;
392 // Insert code to trace values at function entry
393 InsertCodeToShowFunctionEntry(F, externalFuncs.PrintfFunc,
394 externalFuncs.HashPtrFunc);
396 // Push a pointer set for recording alloca'd pointers at entry.
397 if (!DisablePtrHashing)
398 new CallInst(externalFuncs.PushOnEntryFunc, vector<Value*>(), "",
399 F.getEntryNode().begin());
401 for (Function::iterator BB = F.begin(); BB != F.end(); ++BB) {
402 if (isa<ReturnInst>(BB->getTerminator()))
403 exitBlocks.push_back(BB); // record this as an exit block
405 // Insert trace code if this basic block is interesting...
406 handleBasicBlock(BB, valuesStoredInFunction);
408 if (!DisablePtrHashing) // release seq. numbers on free/ret
409 ReleasePtrSeqNumbers(BB, externalFuncs);
412 for (unsigned i=0; i != exitBlocks.size(); ++i)
414 // Insert code to trace values at function exit
415 InsertCodeToShowFunctionExit(exitBlocks[i], externalFuncs.PrintfFunc,
416 externalFuncs.HashPtrFunc);
418 // Release all recorded pointers before RETURN. Do this LAST!
419 if (!DisablePtrHashing)
420 new CallInst(externalFuncs.ReleaseOnReturnFunc, vector<Value*>(), "",
421 exitBlocks[i]->getTerminator());