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 TraceFuncNames("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 &F)
42 if (TraceFuncNames.empty()) return true;
44 return std::find(TraceFuncNames.begin(), TraceFuncNames.end(), F.getName())
45 != TraceFuncNames.end();
50 struct ExternalFuncs {
51 Function *PrintfFunc, *HashPtrFunc, *ReleasePtrFunc;
52 Function *RecordPtrFunc, *PushOnEntryFunc, *ReleaseOnReturnFunc;
53 void doInitialization(Module &M); // Add prototypes for external functions
56 class InsertTraceCode : public FunctionPass {
58 ExternalFuncs externalFuncs;
61 // Add a prototype for runtime functions not already in the program.
63 bool doInitialization(Module &M);
65 //--------------------------------------------------------------------------
66 // Function InsertCodeToTraceValues
68 // Inserts tracing code for all live values at basic block and/or function
69 // exits as specified by `traceBasicBlockExits' and `traceFunctionExits'.
71 bool doit(Function *M);
73 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) = 0;
75 // runOnFunction - This method does the work.
77 bool runOnFunction(Function &F);
79 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
84 struct FunctionTracer : public InsertTraceCode {
85 // Ignore basic blocks here...
86 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {}
89 struct BasicBlockTracer : public InsertTraceCode {
90 // Trace basic blocks here...
91 virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {
92 TraceValuesAtBBExit(BB, externalFuncs.PrintfFunc,
93 externalFuncs.HashPtrFunc, &VI);
97 // Register the passes...
98 RegisterOpt<FunctionTracer> X("tracem","Insert Function trace code only");
99 RegisterOpt<BasicBlockTracer> Y("trace","Insert BB and Function trace code");
100 } // end anonymous namespace
103 Pass *createTraceValuesPassForFunction() { // Just trace functions
104 return new FunctionTracer();
107 Pass *createTraceValuesPassForBasicBlocks() { // Trace BB's and functions
108 return new BasicBlockTracer();
112 // Add a prototype for external functions used by the tracing code.
114 void ExternalFuncs::doInitialization(Module &M) {
115 const Type *SBP = PointerType::get(Type::SByteTy);
116 const FunctionType *MTy =
117 FunctionType::get(Type::IntTy, vector<const Type*>(1, SBP), true);
118 PrintfFunc = M.getOrInsertFunction("printf", MTy);
121 const FunctionType *hashFuncTy =
122 FunctionType::get(Type::UIntTy, vector<const Type*>(1, SBP), false);
123 HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", hashFuncTy);
126 const FunctionType *voidSBPFuncTy =
127 FunctionType::get(Type::VoidTy, vector<const Type*>(1, SBP), false);
129 ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum", voidSBPFuncTy);
130 RecordPtrFunc = M.getOrInsertFunction("RecordPointer", voidSBPFuncTy);
132 const FunctionType *voidvoidFuncTy =
133 FunctionType::get(Type::VoidTy, vector<const Type*>(), false);
135 PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", voidvoidFuncTy);
136 ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
141 // Add a prototype for external functions used by the tracing code.
143 bool InsertTraceCode::doInitialization(Module &M) {
144 externalFuncs.doInitialization(M);
149 static inline GlobalVariable *getStringRef(Module *M, const string &str) {
150 // Create a constant internal string reference...
151 Constant *Init = ConstantArray::get(str);
153 // Create the global variable and record it in the module
154 // The GV will be renamed to a unique name if needed.
155 GlobalVariable *GV = new GlobalVariable(Init->getType(), true, true, Init,
157 M->getGlobalList().push_back(GV);
163 // Check if this instruction has any uses outside its basic block,
164 // or if it used by either a Call or Return instruction.
166 static inline bool LiveAtBBExit(const Instruction* I) {
167 const BasicBlock *BB = I->getParent();
168 for (Value::use_const_iterator U = I->use_begin(); U != I->use_end(); ++U)
169 if (const Instruction *UI = dyn_cast<Instruction>(*U))
170 if (UI->getParent() != BB || isa<ReturnInst>(UI))
177 static inline bool TraceThisOpCode(unsigned opCode) {
178 // Explicitly test for opCodes *not* to trace so that any new opcodes will
179 // be traced by default (VoidTy's are already excluded)
181 return (opCode < Instruction::OtherOpsBegin &&
182 opCode != Instruction::Alloca &&
183 opCode != Instruction::PHINode &&
184 opCode != Instruction::Cast);
188 static bool ShouldTraceValue(const Instruction *I) {
190 I->getType() != Type::VoidTy && LiveAtBBExit(I) &&
191 TraceThisOpCode(I->getOpcode());
194 static string getPrintfCodeFor(const Value *V) {
195 if (V == 0) return "";
196 if (V->getType()->isFloatingPoint())
198 else if (V->getType() == Type::LabelTy)
200 else if (isa<PointerType>(V->getType()))
201 return DisablePtrHashing ? "0x%p" : "%d";
202 else if (V->getType()->isIntegral())
205 assert(0 && "Illegal value to print out...");
210 static void InsertPrintInst(Value *V, BasicBlock *BB, Instruction *InsertBefore,
212 Function *Printf, Function* HashPtrToSeqNum) {
213 // Escape Message by replacing all % characters with %% chars.
215 std::swap(Tmp, Message);
216 string::iterator I = std::find(Tmp.begin(), Tmp.end(), '%');
217 while (I != Tmp.end()) {
218 Message.append(Tmp.begin(), I);
220 ++I; // Make sure to erase the % as well...
221 Tmp.erase(Tmp.begin(), I);
222 I = std::find(Tmp.begin(), Tmp.end(), '%');
225 Module *Mod = BB->getParent()->getParent();
227 // Turn the marker string into a global variable...
228 GlobalVariable *fmtVal = getStringRef(Mod, Message+getPrintfCodeFor(V)+"\n");
230 // Turn the format string into an sbyte *
232 new GetElementPtrInst(fmtVal,
233 vector<Value*>(2,ConstantSInt::get(Type::LongTy, 0)),
234 "trstrp", InsertBefore);
236 // Insert a call to the hash function if this is a pointer value
237 if (V && isa<PointerType>(V->getType()) && !DisablePtrHashing) {
238 const Type *SBP = PointerType::get(Type::SByteTy);
239 if (V->getType() != SBP) // Cast pointer to be sbyte*
240 V = new CastInst(V, SBP, "Hash_cast", InsertBefore);
242 vector<Value*> HashArgs(1, V);
243 V = new CallInst(HashPtrToSeqNum, HashArgs, "ptrSeqNum", InsertBefore);
246 // Insert the first print instruction to print the string flag:
247 vector<Value*> PrintArgs;
248 PrintArgs.push_back(GEP);
249 if (V) PrintArgs.push_back(V);
250 new CallInst(Printf, PrintArgs, "trace", InsertBefore);
254 static void InsertVerbosePrintInst(Value *V, BasicBlock *BB,
255 Instruction *InsertBefore,
256 const string &Message, Function *Printf,
257 Function* HashPtrToSeqNum) {
258 std::ostringstream OutStr;
259 if (V) WriteAsOperand(OutStr, V);
260 InsertPrintInst(V, BB, InsertBefore, Message+OutStr.str()+" = ",
261 Printf, HashPtrToSeqNum);
265 InsertReleaseInst(Value *V, BasicBlock *BB,
266 Instruction *InsertBefore,
267 Function* ReleasePtrFunc) {
269 const Type *SBP = PointerType::get(Type::SByteTy);
270 if (V->getType() != SBP) // Cast pointer to be sbyte*
271 V = new CastInst(V, SBP, "RPSN_cast", InsertBefore);
273 vector<Value*> releaseArgs(1, V);
274 new CallInst(ReleasePtrFunc, releaseArgs, "", InsertBefore);
278 InsertRecordInst(Value *V, BasicBlock *BB,
279 Instruction *InsertBefore,
280 Function* RecordPtrFunc) {
281 const Type *SBP = PointerType::get(Type::SByteTy);
282 if (V->getType() != SBP) // Cast pointer to be sbyte*
283 V = new CastInst(V, SBP, "RP_cast", InsertBefore);
285 vector<Value*> releaseArgs(1, V);
286 new CallInst(RecordPtrFunc, releaseArgs, "", InsertBefore);
289 // Look for alloca and free instructions. These are the ptrs to release.
290 // Release the free'd pointers immediately. Record the alloca'd pointers
291 // to be released on return from the current function.
294 ReleasePtrSeqNumbers(BasicBlock *BB,
295 ExternalFuncs& externalFuncs) {
297 for (BasicBlock::iterator II=BB->begin(), IE = BB->end(); II != IE; ++II)
298 if (FreeInst *FI = dyn_cast<FreeInst>(&*II))
299 InsertReleaseInst(FI->getOperand(0), BB, FI,externalFuncs.ReleasePtrFunc);
300 else if (AllocaInst *AI = dyn_cast<AllocaInst>(&*II))
301 InsertRecordInst(AI, BB, AI->getNext(), externalFuncs.RecordPtrFunc);
305 // Insert print instructions at the end of basic block BB for each value
306 // computed in BB that is live at the end of BB,
307 // or that is stored to memory in BB.
308 // If the value is stored to memory, we load it back before printing it
309 // We also return all such loaded values in the vector valuesStoredInFunction
310 // for printing at the exit from the function. (Note that in each invocation
311 // of the function, this will only get the last value stored for each static
312 // store instruction).
314 static void TraceValuesAtBBExit(BasicBlock *BB,
315 Function *Printf, Function* HashPtrToSeqNum,
316 vector<Instruction*> *valuesStoredInFunction) {
317 // Get an iterator to point to the insertion location, which is
318 // just before the terminator instruction.
320 TerminatorInst *InsertPos = BB->getTerminator();
322 std::ostringstream OutStr;
323 WriteAsOperand(OutStr, BB, false);
324 InsertPrintInst(0, BB, InsertPos, "LEAVING BB:" + OutStr.str(),
325 Printf, HashPtrToSeqNum);
327 // Insert a print instruction for each instruction preceding InsertPos.
328 // The print instructions must go before InsertPos, so we use the
329 // instruction *preceding* InsertPos to check when to terminate the loop.
331 for (BasicBlock::iterator II = BB->begin(); &*II != InsertPos; ++II) {
332 if (StoreInst *SI = dyn_cast<StoreInst>(&*II)) {
333 assert(valuesStoredInFunction &&
334 "Should not be printing a store instruction at function exit");
335 LoadInst *LI = new LoadInst(SI->getPointerOperand(), "reload." +
336 SI->getPointerOperand()->getName(),
338 valuesStoredInFunction->push_back(LI);
340 if (ShouldTraceValue(II))
341 InsertVerbosePrintInst(II, BB, InsertPos, " ", Printf, HashPtrToSeqNum);
345 static inline void InsertCodeToShowFunctionEntry(Function &F, Function *Printf,
346 Function* HashPtrToSeqNum){
347 // Get an iterator to point to the insertion location
348 BasicBlock &BB = F.getEntryNode();
349 Instruction *InsertPos = BB.begin();
351 std::ostringstream OutStr;
352 WriteAsOperand(OutStr, &F);
353 InsertPrintInst(0, &BB, InsertPos, "ENTERING FUNCTION: " + OutStr.str(),
354 Printf, HashPtrToSeqNum);
356 // Now print all the incoming arguments
358 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++ArgNo){
359 InsertVerbosePrintInst(I, &BB, InsertPos,
360 " Arg #" + utostr(ArgNo) + ": ", Printf,
366 static inline void InsertCodeToShowFunctionExit(BasicBlock *BB,
368 Function* HashPtrToSeqNum) {
369 // Get an iterator to point to the insertion location
370 ReturnInst *Ret = cast<ReturnInst>(BB->getTerminator());
372 std::ostringstream OutStr;
373 WriteAsOperand(OutStr, BB->getParent(), true);
374 InsertPrintInst(0, BB, Ret, "LEAVING FUNCTION: " + OutStr.str(),
375 Printf, HashPtrToSeqNum);
377 // print the return value, if any
378 if (BB->getParent()->getReturnType() != Type::VoidTy)
379 InsertPrintInst(Ret->getReturnValue(), BB, Ret, " Returning: ",
380 Printf, HashPtrToSeqNum);
384 bool InsertTraceCode::runOnFunction(Function &F) {
385 if (!TraceThisFunction(F))
388 vector<Instruction*> valuesStoredInFunction;
389 vector<BasicBlock*> exitBlocks;
391 // Insert code to trace values at function entry
392 InsertCodeToShowFunctionEntry(F, externalFuncs.PrintfFunc,
393 externalFuncs.HashPtrFunc);
395 // Push a pointer set for recording alloca'd pointers at entry.
396 if (!DisablePtrHashing)
397 new CallInst(externalFuncs.PushOnEntryFunc, vector<Value*>(), "",
398 F.getEntryNode().begin());
400 for (Function::iterator BB = F.begin(); BB != F.end(); ++BB) {
401 if (isa<ReturnInst>(BB->getTerminator()))
402 exitBlocks.push_back(BB); // record this as an exit block
404 // Insert trace code if this basic block is interesting...
405 handleBasicBlock(BB, valuesStoredInFunction);
407 if (!DisablePtrHashing) // release seq. numbers on free/ret
408 ReleasePtrSeqNumbers(BB, externalFuncs);
411 for (unsigned i=0; i != exitBlocks.size(); ++i)
413 // Insert code to trace values at function exit
414 InsertCodeToShowFunctionExit(exitBlocks[i], externalFuncs.PrintfFunc,
415 externalFuncs.HashPtrFunc);
417 // Release all recorded pointers before RETURN. Do this LAST!
418 if (!DisablePtrHashing)
419 new CallInst(externalFuncs.ReleaseOnReturnFunc, vector<Value*>(), "",
420 exitBlocks[i]->getTerminator());