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/TraceValues.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"));
28 static cl::list<string>
29 TraceFuncName("tracefunc", cl::desc("trace only specific functions"),
30 cl::value_desc("function"), cl::Hidden);
32 static void TraceValuesAtBBExit(BasicBlock *BB,
33 Function *Printf, Function* HashPtrToSeqNum,
34 vector<Instruction*> *valuesStoredInFunction);
36 // We trace a particular function if no functions to trace were specified
37 // or if the function is in the specified list.
40 TraceThisFunction(Function &func)
42 if (TraceFuncName.size() == 0)
45 return std::find(TraceFuncName.begin(), TraceFuncName.end(), func.getName())
46 != TraceFuncName.end();
51 struct ExternalFuncs {
52 Function *PrintfFunc, *HashPtrFunc, *ReleasePtrFunc;
53 Function *RecordPtrFunc, *PushOnEntryFunc, *ReleaseOnReturnFunc;
54 void doInitialization(Module &M); // Add prototypes for external functions
57 class InsertTraceCode : public FunctionPass {
59 ExternalFuncs externalFuncs;
62 // Add a prototype for runtime functions not already in the program.
64 bool doInitialization(Module &M);
66 //--------------------------------------------------------------------------
67 // Function InsertCodeToTraceValues
69 // Inserts tracing code for all live values at basic block and/or function
70 // exits as specified by `traceBasicBlockExits' and `traceFunctionExits'.
72 bool doit(Function *M);
74 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) = 0;
76 // runOnFunction - This method does the work.
78 bool runOnFunction(Function &F);
80 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
85 struct FunctionTracer : public InsertTraceCode {
86 // Ignore basic blocks here...
87 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {}
90 struct BasicBlockTracer : public InsertTraceCode {
91 // Trace basic blocks here...
92 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {
93 TraceValuesAtBBExit(BB, externalFuncs.PrintfFunc,
94 externalFuncs.HashPtrFunc, &VI);
98 // Register the passes...
99 RegisterOpt<FunctionTracer> X("tracem","Insert Function trace code only");
100 RegisterOpt<BasicBlockTracer> Y("trace","Insert BB and Function trace code");
101 } // end anonymous namespace
104 Pass *createTraceValuesPassForFunction() { // Just trace functions
105 return new FunctionTracer();
108 Pass *createTraceValuesPassForBasicBlocks() { // Trace BB's and functions
109 return new BasicBlockTracer();
113 // Add a prototype for external functions used by the tracing code.
115 void ExternalFuncs::doInitialization(Module &M) {
116 const Type *SBP = PointerType::get(Type::SByteTy);
117 const FunctionType *MTy =
118 FunctionType::get(Type::IntTy, vector<const Type*>(1, SBP), true);
119 PrintfFunc = M.getOrInsertFunction("printf", MTy);
122 const FunctionType *hashFuncTy =
123 FunctionType::get(Type::UIntTy, vector<const Type*>(1, SBP), false);
124 HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", hashFuncTy);
127 const FunctionType *voidSBPFuncTy =
128 FunctionType::get(Type::VoidTy, vector<const Type*>(1, SBP), false);
130 ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum", voidSBPFuncTy);
131 RecordPtrFunc = M.getOrInsertFunction("RecordPointer", voidSBPFuncTy);
133 const FunctionType *voidvoidFuncTy =
134 FunctionType::get(Type::VoidTy, vector<const Type*>(), false);
136 PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", voidvoidFuncTy);
137 ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
142 // Add a prototype for external functions used by the tracing code.
144 bool InsertTraceCode::doInitialization(Module &M) {
145 externalFuncs.doInitialization(M);
150 static inline GlobalVariable *getStringRef(Module *M, const string &str) {
151 // Create a constant internal string reference...
152 Constant *Init = ConstantArray::get(str);
154 // Create the global variable and record it in the module
155 // The GV will be renamed to a unique name if needed.
156 GlobalVariable *GV = new GlobalVariable(Init->getType(), true, true, Init,
158 M->getGlobalList().push_back(GV);
164 // Check if this instruction has any uses outside its basic block,
165 // or if it used by either a Call or Return instruction.
167 static inline bool LiveAtBBExit(const Instruction* I) {
168 const BasicBlock *BB = I->getParent();
169 for (Value::use_const_iterator U = I->use_begin(); U != I->use_end(); ++U)
170 if (const Instruction *UI = dyn_cast<Instruction>(*U))
171 if (UI->getParent() != BB || isa<ReturnInst>(UI))
178 static inline bool TraceThisOpCode(unsigned opCode) {
179 // Explicitly test for opCodes *not* to trace so that any new opcodes will
180 // be traced by default (VoidTy's are already excluded)
182 return (opCode < Instruction::FirstOtherOp &&
183 opCode != Instruction::Alloca &&
184 opCode != Instruction::PHINode &&
185 opCode != Instruction::Cast);
189 static bool ShouldTraceValue(const Instruction *I) {
191 I->getType() != Type::VoidTy && LiveAtBBExit(I) &&
192 TraceThisOpCode(I->getOpcode());
195 static string getPrintfCodeFor(const Value *V) {
196 if (V == 0) return "";
197 if (V->getType()->isFloatingPoint())
199 else if (V->getType() == Type::LabelTy)
201 else if (isa<PointerType>(V->getType()))
202 return DisablePtrHashing ? "0x%p" : "%d";
203 else if (V->getType()->isIntegral() || V->getType() == Type::BoolTy)
206 assert(0 && "Illegal value to print out...");
211 static void InsertPrintInst(Value *V,BasicBlock *BB, BasicBlock::iterator &BBI,
213 Function *Printf, Function* HashPtrToSeqNum) {
214 // Escape Message by replacing all % characters with %% chars.
216 while ((Offset = Message.find('%', Offset)) != string::npos) {
217 Message.replace(Offset, 1, "%%");
218 Offset += 2; // Skip over the new %'s
221 Module *Mod = BB->getParent()->getParent();
223 // Turn the marker string into a global variable...
224 GlobalVariable *fmtVal = getStringRef(Mod, Message+getPrintfCodeFor(V)+"\n");
226 // Turn the format string into an sbyte *
228 new GetElementPtrInst(fmtVal,
229 vector<Value*>(2,ConstantUInt::get(Type::UIntTy, 0)),
231 BBI = ++BB->getInstList().insert(BBI, GEP);
233 // Insert a call to the hash function if this is a pointer value
234 if (V && isa<PointerType>(V->getType()) && !DisablePtrHashing) {
235 const Type *SBP = PointerType::get(Type::SByteTy);
236 if (V->getType() != SBP) { // Cast pointer to be sbyte*
237 Instruction *I = new CastInst(V, SBP, "Hash_cast");
238 BBI = ++BB->getInstList().insert(BBI, I);
242 vector<Value*> HashArgs(1, V);
243 V = new CallInst(HashPtrToSeqNum, HashArgs, "ptrSeqNum");
244 BBI = ++BB->getInstList().insert(BBI, cast<Instruction>(V));
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 Instruction *I = new CallInst(Printf, PrintArgs, "trace");
252 BBI = ++BB->getInstList().insert(BBI, I);
256 static void InsertVerbosePrintInst(Value *V, BasicBlock *BB,
257 BasicBlock::iterator &BBI,
258 const string &Message, Function *Printf,
259 Function* HashPtrToSeqNum) {
260 std::ostringstream OutStr;
261 if (V) WriteAsOperand(OutStr, V);
262 InsertPrintInst(V, BB, BBI, Message+OutStr.str()+" = ",
263 Printf, HashPtrToSeqNum);
267 InsertReleaseInst(Value *V, BasicBlock *BB,
268 BasicBlock::iterator &BBI,
269 Function* ReleasePtrFunc) {
271 const Type *SBP = PointerType::get(Type::SByteTy);
272 if (V->getType() != SBP) { // Cast pointer to be sbyte*
273 Instruction *I = new CastInst(V, SBP, "RPSN_cast");
274 BBI = ++BB->getInstList().insert(BBI, I);
277 vector<Value*> releaseArgs(1, V);
278 Instruction *I = new CallInst(ReleasePtrFunc, releaseArgs);
279 BBI = ++BB->getInstList().insert(BBI, I);
283 InsertRecordInst(Value *V, BasicBlock *BB,
284 BasicBlock::iterator &BBI,
285 Function* RecordPtrFunc) {
286 const Type *SBP = PointerType::get(Type::SByteTy);
287 if (V->getType() != SBP) { // Cast pointer to be sbyte*
288 Instruction *I = new CastInst(V, SBP, "RP_cast");
289 BBI = ++BB->getInstList().insert(BBI, I);
292 vector<Value*> releaseArgs(1, V);
293 Instruction *I = new CallInst(RecordPtrFunc, releaseArgs);
294 BBI = ++BB->getInstList().insert(BBI, I);
298 InsertPushOnEntryFunc(Function *M,
299 Function* PushOnEntryFunc) {
300 // Get an iterator to point to the insertion location
301 BasicBlock &BB = M->getEntryNode();
302 BB.getInstList().insert(BB.begin(), new CallInst(PushOnEntryFunc,
307 InsertReleaseRecordedInst(BasicBlock *BB,
308 Function* ReleaseOnReturnFunc) {
309 BasicBlock::iterator BBI = --BB->end();
310 BBI = ++BB->getInstList().insert(BBI, new CallInst(ReleaseOnReturnFunc,
314 // Look for alloca and free instructions. These are the ptrs to release.
315 // Release the free'd pointers immediately. Record the alloca'd pointers
316 // to be released on return from the current function.
319 ReleasePtrSeqNumbers(BasicBlock *BB,
320 ExternalFuncs& externalFuncs) {
322 for (BasicBlock::iterator II=BB->begin(); II != BB->end(); ++II) {
323 if (FreeInst *FI = dyn_cast<FreeInst>(&*II))
324 InsertReleaseInst(FI->getOperand(0), BB,II,externalFuncs.ReleasePtrFunc);
325 else if (AllocaInst *AI = dyn_cast<AllocaInst>(&*II))
327 BasicBlock::iterator nextI = ++II;
328 InsertRecordInst(AI, BB, nextI, externalFuncs.RecordPtrFunc);
335 // Insert print instructions at the end of basic block BB for each value
336 // computed in BB that is live at the end of BB,
337 // or that is stored to memory in BB.
338 // If the value is stored to memory, we load it back before printing it
339 // We also return all such loaded values in the vector valuesStoredInFunction
340 // for printing at the exit from the function. (Note that in each invocation
341 // of the function, this will only get the last value stored for each static
342 // store instruction).
344 static void TraceValuesAtBBExit(BasicBlock *BB,
345 Function *Printf, Function* HashPtrToSeqNum,
346 vector<Instruction*> *valuesStoredInFunction) {
347 // Get an iterator to point to the insertion location, which is
348 // just before the terminator instruction.
350 BasicBlock::iterator InsertPos = --BB->end();
351 assert(InsertPos->isTerminator());
353 std::ostringstream OutStr;
354 WriteAsOperand(OutStr, BB, false);
355 InsertPrintInst(0, BB, InsertPos, "LEAVING BB:" + OutStr.str(),
356 Printf, HashPtrToSeqNum);
358 // Insert a print instruction for each instruction preceding InsertPos.
359 // The print instructions must go before InsertPos, so we use the
360 // instruction *preceding* InsertPos to check when to terminate the loop.
362 if (InsertPos != BB->begin()) { // there's at least one instr before InsertPos
363 BasicBlock::iterator II = BB->begin(), IEincl = InsertPos;
365 do { // do from II up to IEincl, inclusive
366 if (StoreInst *SI = dyn_cast<StoreInst>(&*II)) {
367 assert(valuesStoredInFunction &&
368 "Should not be printing a store instruction at function exit");
369 LoadInst *LI = new LoadInst(SI->getPointerOperand(), "reload." +
370 SI->getPointerOperand()->getName());
371 InsertPos = ++BB->getInstList().insert(InsertPos, LI);
372 valuesStoredInFunction->push_back(LI);
374 if (ShouldTraceValue(II))
375 InsertVerbosePrintInst(II, BB, InsertPos, " ", Printf,HashPtrToSeqNum);
376 } while (II++ != IEincl);
380 static inline void InsertCodeToShowFunctionEntry(Function &F, Function *Printf,
381 Function* HashPtrToSeqNum){
382 // Get an iterator to point to the insertion location
383 BasicBlock &BB = F.getEntryNode();
384 BasicBlock::iterator BBI = BB.begin();
386 std::ostringstream OutStr;
387 WriteAsOperand(OutStr, &F, true);
388 InsertPrintInst(0, &BB, BBI, "ENTERING FUNCTION: " + OutStr.str(),
389 Printf, HashPtrToSeqNum);
391 // Now print all the incoming arguments
393 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++ArgNo){
394 InsertVerbosePrintInst(I, &BB, BBI,
395 " Arg #" + utostr(ArgNo) + ": ", Printf,
401 static inline void InsertCodeToShowFunctionExit(BasicBlock *BB,
403 Function* HashPtrToSeqNum) {
404 // Get an iterator to point to the insertion location
405 BasicBlock::iterator BBI = --BB->end();
406 ReturnInst &Ret = cast<ReturnInst>(BB->back());
408 std::ostringstream OutStr;
409 WriteAsOperand(OutStr, BB->getParent(), true);
410 InsertPrintInst(0, BB, BBI, "LEAVING FUNCTION: " + OutStr.str(),
411 Printf, HashPtrToSeqNum);
413 // print the return value, if any
414 if (BB->getParent()->getReturnType() != Type::VoidTy)
415 InsertPrintInst(Ret.getReturnValue(), BB, BBI, " Returning: ",
416 Printf, HashPtrToSeqNum);
420 bool InsertTraceCode::runOnFunction(Function &F) {
421 if (!TraceThisFunction(F))
424 vector<Instruction*> valuesStoredInFunction;
425 vector<BasicBlock*> exitBlocks;
427 // Insert code to trace values at function entry
428 InsertCodeToShowFunctionEntry(F, externalFuncs.PrintfFunc,
429 externalFuncs.HashPtrFunc);
431 // Push a pointer set for recording alloca'd pointers at entry.
432 if (!DisablePtrHashing)
433 InsertPushOnEntryFunc(&F, externalFuncs.PushOnEntryFunc);
435 for (Function::iterator BB = F.begin(); BB != F.end(); ++BB) {
436 if (isa<ReturnInst>(BB->getTerminator()))
437 exitBlocks.push_back(BB); // record this as an exit block
439 // Insert trace code if this basic block is interesting...
440 handleBasicBlock(BB, valuesStoredInFunction);
442 if (!DisablePtrHashing) // release seq. numbers on free/ret
443 ReleasePtrSeqNumbers(BB, externalFuncs);
446 for (unsigned i=0; i != exitBlocks.size(); ++i)
448 // Insert code to trace values at function exit
449 InsertCodeToShowFunctionExit(exitBlocks[i], externalFuncs.PrintfFunc,
450 externalFuncs.HashPtrFunc);
452 // Release all recorded pointers before RETURN. Do this LAST!
453 if (!DisablePtrHashing)
454 InsertReleaseRecordedInst(exitBlocks[i],
455 externalFuncs.ReleaseOnReturnFunc);