1 //===- TraceValues.cpp - Value Tracing for debugging ----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Support for inserting LLVM code to print values at basic block and function
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Transforms/Instrumentation.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Instructions.h"
19 #include "llvm/Module.h"
20 #include "llvm/Pass.h"
21 #include "llvm/Assembly/Writer.h"
22 #include "llvm/Support/CommandLine.h"
23 #include "llvm/ADT/StringExtras.h"
29 DisablePtrHashing("tracedisablehashdisable", cl::Hidden,
30 cl::desc("Disable pointer hashing in the -trace or -tracem "
33 static cl::list<std::string>
34 TraceFuncNames("tracefunc", cl::desc("Only trace specific functions in the "
35 "-trace or -tracem passes"),
36 cl::value_desc("function"), cl::Hidden);
38 static void TraceValuesAtBBExit(BasicBlock *BB,
39 Function *Printf, Function* HashPtrToSeqNum,
40 std::vector<Instruction*> *valuesStoredInFunction);
42 // We trace a particular function if no functions to trace were specified
43 // or if the function is in the specified list.
46 TraceThisFunction(Function &F)
48 if (TraceFuncNames.empty()) return true;
50 return std::find(TraceFuncNames.begin(), TraceFuncNames.end(), F.getName())
51 != TraceFuncNames.end();
56 struct ExternalFuncs {
57 Function *PrintfFunc, *HashPtrFunc, *ReleasePtrFunc;
58 Function *RecordPtrFunc, *PushOnEntryFunc, *ReleaseOnReturnFunc;
59 void doInitialization(Module &M); // Add prototypes for external functions
62 class InsertTraceCode : public FunctionPass {
64 ExternalFuncs externalFuncs;
67 // Add a prototype for runtime functions not already in the program.
69 bool doInitialization(Module &M);
71 //--------------------------------------------------------------------------
72 // Function InsertCodeToTraceValues
74 // Inserts tracing code for all live values at basic block and/or function
75 // exits as specified by `traceBasicBlockExits' and `traceFunctionExits'.
77 bool doit(Function *M);
79 virtual void handleBasicBlock(BasicBlock *BB,
80 std::vector<Instruction*> &VI) = 0;
82 // runOnFunction - This method does the work.
84 bool runOnFunction(Function &F);
86 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
91 struct FunctionTracer : public InsertTraceCode {
92 // Ignore basic blocks here...
93 virtual void handleBasicBlock(BasicBlock *BB,
94 std::vector<Instruction*> &VI) {}
97 struct BasicBlockTracer : public InsertTraceCode {
98 // Trace basic blocks here...
99 virtual void handleBasicBlock(BasicBlock *BB,
100 std::vector<Instruction*> &VI) {
101 TraceValuesAtBBExit(BB, externalFuncs.PrintfFunc,
102 externalFuncs.HashPtrFunc, &VI);
106 // Register the passes...
107 RegisterOpt<FunctionTracer> X("tracem","Insert Function trace code only");
108 RegisterOpt<BasicBlockTracer> Y("trace","Insert BB and Function trace code");
109 } // end anonymous namespace
111 /// Just trace functions
112 FunctionPass *llvm::createTraceValuesPassForFunction() {
113 return new FunctionTracer();
116 /// Trace BB's and functions
117 FunctionPass *llvm::createTraceValuesPassForBasicBlocks() {
118 return new BasicBlockTracer();
121 // Add a prototype for external functions used by the tracing code and require
122 // the trace library for this module.
124 void ExternalFuncs::doInitialization(Module &M) {
125 M.addLibrary("trace");
126 const Type *SBP = PointerType::get(Type::SByteTy);
127 const FunctionType *MTy =
128 FunctionType::get(Type::IntTy, std::vector<const Type*>(1, SBP), true);
129 PrintfFunc = M.getOrInsertFunction("printf", MTy);
132 HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", Type::UIntTy, SBP,
136 ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum",
137 Type::VoidTy, SBP, (Type *)0);
138 RecordPtrFunc = M.getOrInsertFunction("RecordPointer",
139 Type::VoidTy, SBP, (Type *)0);
141 PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", Type::VoidTy,
143 ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
144 Type::VoidTy, (Type *)0);
148 // Add a prototype for external functions used by the tracing code.
150 bool InsertTraceCode::doInitialization(Module &M) {
151 externalFuncs.doInitialization(M);
156 static inline GlobalVariable *getStringRef(Module *M, const std::string &str) {
157 // Create a constant internal string reference...
158 Constant *Init = ConstantArray::get(str);
160 // Create the global variable and record it in the module
161 // The GV will be renamed to a unique name if needed.
162 GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
163 GlobalValue::InternalLinkage, Init,
165 M->getGlobalList().push_back(GV);
171 // Check if this instruction has any uses outside its basic block,
172 // or if it used by either a Call or Return instruction (ditto).
173 // (Values stored to memory within this BB are live at end of BB but are
174 // traced at the store instruction, not where they are computed.)
176 static inline bool LiveAtBBExit(const Instruction* I) {
177 const BasicBlock *BB = I->getParent();
178 for (Value::use_const_iterator U = I->use_begin(); U != I->use_end(); ++U)
179 if (const Instruction *UI = dyn_cast<Instruction>(*U))
180 if (UI->getParent() != BB || isa<ReturnInst>(UI))
187 static inline bool TraceThisOpCode(unsigned opCode) {
188 // Explicitly test for opCodes *not* to trace so that any new opcodes will
189 // be traced by default (VoidTy's are already excluded)
191 return (opCode < Instruction::OtherOpsBegin &&
192 opCode != Instruction::Alloca &&
193 opCode != Instruction::PHI &&
194 opCode != Instruction::Cast);
198 // Trace a value computed by an instruction if it is non-void, it is computed
199 // by a real computation, not just a copy (see TraceThisOpCode), and
200 // -- it is a load instruction: we want to check values read from memory
201 // -- or it is live at exit from the basic block (i.e., ignore local temps)
203 static bool ShouldTraceValue(const Instruction *I) {
205 I->getType() != Type::VoidTy &&
206 TraceThisOpCode(I->getOpcode()) &&
207 (isa<LoadInst>(I) || LiveAtBBExit(I));
210 static std::string getPrintfCodeFor(const Value *V) {
211 if (V == 0) return "";
212 if (V->getType()->isFloatingPoint())
214 else if (V->getType() == Type::LabelTy)
216 else if (isa<PointerType>(V->getType()))
217 return DisablePtrHashing ? "0x%p" : "%d";
218 else if (V->getType()->isIntegral())
221 assert(0 && "Illegal value to print out...");
226 static void InsertPrintInst(Value *V, BasicBlock *BB, Instruction *InsertBefore,
228 Function *Printf, Function* HashPtrToSeqNum) {
229 // Escape Message by replacing all % characters with %% chars.
231 std::swap(Tmp, Message);
232 std::string::iterator I = std::find(Tmp.begin(), Tmp.end(), '%');
233 while (I != Tmp.end()) {
234 Message.append(Tmp.begin(), I);
236 ++I; // Make sure to erase the % as well...
237 Tmp.erase(Tmp.begin(), I);
238 I = std::find(Tmp.begin(), Tmp.end(), '%');
241 Module *Mod = BB->getParent()->getParent();
243 // Turn the marker string into a global variable...
244 GlobalVariable *fmtVal = getStringRef(Mod, Message+getPrintfCodeFor(V)+"\n");
246 // Turn the format string into an sbyte *
247 Constant *GEP=ConstantExpr::getGetElementPtr(fmtVal,
248 std::vector<Constant*>(2,Constant::getNullValue(Type::LongTy)));
250 // Insert a call to the hash function if this is a pointer value
251 if (V && isa<PointerType>(V->getType()) && !DisablePtrHashing) {
252 const Type *SBP = PointerType::get(Type::SByteTy);
253 if (V->getType() != SBP) // Cast pointer to be sbyte*
254 V = new CastInst(V, SBP, "Hash_cast", InsertBefore);
256 std::vector<Value*> HashArgs(1, V);
257 V = new CallInst(HashPtrToSeqNum, HashArgs, "ptrSeqNum", InsertBefore);
260 // Insert the first print instruction to print the string flag:
261 std::vector<Value*> PrintArgs;
262 PrintArgs.push_back(GEP);
263 if (V) PrintArgs.push_back(V);
264 new CallInst(Printf, PrintArgs, "trace", InsertBefore);
268 static void InsertVerbosePrintInst(Value *V, BasicBlock *BB,
269 Instruction *InsertBefore,
270 const std::string &Message, Function *Printf,
271 Function* HashPtrToSeqNum) {
272 std::ostringstream OutStr;
273 if (V) WriteAsOperand(OutStr, V);
274 InsertPrintInst(V, BB, InsertBefore, Message+OutStr.str()+" = ",
275 Printf, HashPtrToSeqNum);
279 InsertReleaseInst(Value *V, BasicBlock *BB,
280 Instruction *InsertBefore,
281 Function* ReleasePtrFunc) {
283 const Type *SBP = PointerType::get(Type::SByteTy);
284 if (V->getType() != SBP) // Cast pointer to be sbyte*
285 V = new CastInst(V, SBP, "RPSN_cast", InsertBefore);
287 std::vector<Value*> releaseArgs(1, V);
288 new CallInst(ReleasePtrFunc, releaseArgs, "", InsertBefore);
292 InsertRecordInst(Value *V, BasicBlock *BB,
293 Instruction *InsertBefore,
294 Function* RecordPtrFunc) {
295 const Type *SBP = PointerType::get(Type::SByteTy);
296 if (V->getType() != SBP) // Cast pointer to be sbyte*
297 V = new CastInst(V, SBP, "RP_cast", InsertBefore);
299 std::vector<Value*> releaseArgs(1, V);
300 new CallInst(RecordPtrFunc, releaseArgs, "", InsertBefore);
303 // Look for alloca and free instructions. These are the ptrs to release.
304 // Release the free'd pointers immediately. Record the alloca'd pointers
305 // to be released on return from the current function.
308 ReleasePtrSeqNumbers(BasicBlock *BB,
309 ExternalFuncs& externalFuncs) {
311 for (BasicBlock::iterator II=BB->begin(), IE = BB->end(); II != IE; ++II)
312 if (FreeInst *FI = dyn_cast<FreeInst>(II))
313 InsertReleaseInst(FI->getOperand(0), BB, FI,externalFuncs.ReleasePtrFunc);
314 else if (AllocaInst *AI = dyn_cast<AllocaInst>(II))
315 InsertRecordInst(AI, BB, AI->getNext(), externalFuncs.RecordPtrFunc);
319 // Insert print instructions at the end of basic block BB for each value
320 // computed in BB that is live at the end of BB,
321 // or that is stored to memory in BB.
322 // If the value is stored to memory, we load it back before printing it
323 // We also return all such loaded values in the vector valuesStoredInFunction
324 // for printing at the exit from the function. (Note that in each invocation
325 // of the function, this will only get the last value stored for each static
326 // store instruction).
328 static void TraceValuesAtBBExit(BasicBlock *BB,
329 Function *Printf, Function* HashPtrToSeqNum,
330 std::vector<Instruction*> *valuesStoredInFunction) {
331 // Get an iterator to point to the insertion location, which is
332 // just before the terminator instruction.
334 TerminatorInst *InsertPos = BB->getTerminator();
336 std::ostringstream OutStr;
337 WriteAsOperand(OutStr, BB, false);
338 InsertPrintInst(0, BB, InsertPos, "LEAVING BB:" + OutStr.str(),
339 Printf, HashPtrToSeqNum);
341 // Insert a print instruction for each instruction preceding InsertPos.
342 // The print instructions must go before InsertPos, so we use the
343 // instruction *preceding* InsertPos to check when to terminate the loop.
345 for (BasicBlock::iterator II = BB->begin(); &*II != InsertPos; ++II) {
346 if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
347 // Trace the stored value and address
348 InsertVerbosePrintInst(SI->getOperand(0), BB, InsertPos,
349 " (store value) ", Printf, HashPtrToSeqNum);
350 InsertVerbosePrintInst(SI->getOperand(1), BB, InsertPos,
351 " (store addr ) ", Printf, HashPtrToSeqNum);
353 else if (ShouldTraceValue(II))
354 InsertVerbosePrintInst(II, BB, InsertPos, " ", Printf, HashPtrToSeqNum);
358 static inline void InsertCodeToShowFunctionEntry(Function &F, Function *Printf,
359 Function* HashPtrToSeqNum){
360 // Get an iterator to point to the insertion location
361 BasicBlock &BB = F.getEntryBlock();
362 Instruction *InsertPos = BB.begin();
364 std::ostringstream OutStr;
365 WriteAsOperand(OutStr, &F);
366 InsertPrintInst(0, &BB, InsertPos, "ENTERING FUNCTION: " + OutStr.str(),
367 Printf, HashPtrToSeqNum);
369 // Now print all the incoming arguments
371 for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I, ++ArgNo){
372 InsertVerbosePrintInst(I, &BB, InsertPos,
373 " Arg #" + utostr(ArgNo) + ": ", Printf,
379 static inline void InsertCodeToShowFunctionExit(BasicBlock *BB,
381 Function* HashPtrToSeqNum) {
382 // Get an iterator to point to the insertion location
383 ReturnInst *Ret = cast<ReturnInst>(BB->getTerminator());
385 std::ostringstream OutStr;
386 WriteAsOperand(OutStr, BB->getParent(), true);
387 InsertPrintInst(0, BB, Ret, "LEAVING FUNCTION: " + OutStr.str(),
388 Printf, HashPtrToSeqNum);
390 // print the return value, if any
391 if (BB->getParent()->getReturnType() != Type::VoidTy)
392 InsertPrintInst(Ret->getReturnValue(), BB, Ret, " Returning: ",
393 Printf, HashPtrToSeqNum);
397 bool InsertTraceCode::runOnFunction(Function &F) {
398 if (!TraceThisFunction(F))
401 std::vector<Instruction*> valuesStoredInFunction;
402 std::vector<BasicBlock*> exitBlocks;
404 // Insert code to trace values at function entry
405 InsertCodeToShowFunctionEntry(F, externalFuncs.PrintfFunc,
406 externalFuncs.HashPtrFunc);
408 // Push a pointer set for recording alloca'd pointers at entry.
409 if (!DisablePtrHashing)
410 new CallInst(externalFuncs.PushOnEntryFunc, std::vector<Value*>(), "",
411 F.getEntryBlock().begin());
413 for (Function::iterator BB = F.begin(); BB != F.end(); ++BB) {
414 if (isa<ReturnInst>(BB->getTerminator()))
415 exitBlocks.push_back(BB); // record this as an exit block
417 // Insert trace code if this basic block is interesting...
418 handleBasicBlock(BB, valuesStoredInFunction);
420 if (!DisablePtrHashing) // release seq. numbers on free/ret
421 ReleasePtrSeqNumbers(BB, externalFuncs);
424 for (unsigned i=0; i != exitBlocks.size(); ++i)
426 // Insert code to trace values at function exit
427 InsertCodeToShowFunctionExit(exitBlocks[i], externalFuncs.PrintfFunc,
428 externalFuncs.HashPtrFunc);
430 // Release all recorded pointers before RETURN. Do this LAST!
431 if (!DisablePtrHashing)
432 new CallInst(externalFuncs.ReleaseOnReturnFunc, std::vector<Value*>(),
433 "", exitBlocks[i]->getTerminator());