1 //===- TraceValues.cpp - Value Tracing for debugging ----------------------===//
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 HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", Type::UIntTy, SBP,
127 ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum",
128 Type::VoidTy, SBP, 0);
129 RecordPtrFunc = M.getOrInsertFunction("RecordPointer",
130 Type::VoidTy, SBP, 0);
132 PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", Type::VoidTy, 0);
133 ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
138 // Add a prototype for external functions used by the tracing code.
140 bool InsertTraceCode::doInitialization(Module &M) {
141 externalFuncs.doInitialization(M);
146 static inline GlobalVariable *getStringRef(Module *M, const string &str) {
147 // Create a constant internal string reference...
148 Constant *Init = ConstantArray::get(str);
150 // Create the global variable and record it in the module
151 // The GV will be renamed to a unique name if needed.
152 GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
153 GlobalValue::InternalLinkage, Init,
155 M->getGlobalList().push_back(GV);
161 // Check if this instruction has any uses outside its basic block,
162 // or if it used by either a Call or Return instruction (ditto).
163 // (Values stored to memory within this BB are live at end of BB but are
164 // traced at the store instruction, not where they are computed.)
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 // Trace a value computed by an instruction if it is non-void, it is computed
189 // by a real computation, not just a copy (see TraceThisOpCode), and
190 // -- it is a load instruction: we want to check values read from memory
191 // -- or it is live at exit from the basic block (i.e., ignore local temps)
193 static bool ShouldTraceValue(const Instruction *I) {
195 I->getType() != Type::VoidTy &&
196 TraceThisOpCode(I->getOpcode()) &&
197 (isa<LoadInst>(I) || LiveAtBBExit(I));
200 static string getPrintfCodeFor(const Value *V) {
201 if (V == 0) return "";
202 if (V->getType()->isFloatingPoint())
204 else if (V->getType() == Type::LabelTy)
206 else if (isa<PointerType>(V->getType()))
207 return DisablePtrHashing ? "0x%p" : "%d";
208 else if (V->getType()->isIntegral())
211 assert(0 && "Illegal value to print out...");
216 static void InsertPrintInst(Value *V, BasicBlock *BB, Instruction *InsertBefore,
218 Function *Printf, Function* HashPtrToSeqNum) {
219 // Escape Message by replacing all % characters with %% chars.
221 std::swap(Tmp, Message);
222 string::iterator I = std::find(Tmp.begin(), Tmp.end(), '%');
223 while (I != Tmp.end()) {
224 Message.append(Tmp.begin(), I);
226 ++I; // Make sure to erase the % as well...
227 Tmp.erase(Tmp.begin(), I);
228 I = std::find(Tmp.begin(), Tmp.end(), '%');
231 Module *Mod = BB->getParent()->getParent();
233 // Turn the marker string into a global variable...
234 GlobalVariable *fmtVal = getStringRef(Mod, Message+getPrintfCodeFor(V)+"\n");
236 // Turn the format string into an sbyte *
237 Constant *GEP =ConstantExpr::getGetElementPtr(ConstantPointerRef::get(fmtVal),
238 vector<Constant*>(2,Constant::getNullValue(Type::LongTy)));
240 // Insert a call to the hash function if this is a pointer value
241 if (V && isa<PointerType>(V->getType()) && !DisablePtrHashing) {
242 const Type *SBP = PointerType::get(Type::SByteTy);
243 if (V->getType() != SBP) // Cast pointer to be sbyte*
244 V = new CastInst(V, SBP, "Hash_cast", InsertBefore);
246 vector<Value*> HashArgs(1, V);
247 V = new CallInst(HashPtrToSeqNum, HashArgs, "ptrSeqNum", InsertBefore);
250 // Insert the first print instruction to print the string flag:
251 vector<Value*> PrintArgs;
252 PrintArgs.push_back(GEP);
253 if (V) PrintArgs.push_back(V);
254 new CallInst(Printf, PrintArgs, "trace", InsertBefore);
258 static void InsertVerbosePrintInst(Value *V, BasicBlock *BB,
259 Instruction *InsertBefore,
260 const string &Message, Function *Printf,
261 Function* HashPtrToSeqNum) {
262 std::ostringstream OutStr;
263 if (V) WriteAsOperand(OutStr, V);
264 InsertPrintInst(V, BB, InsertBefore, Message+OutStr.str()+" = ",
265 Printf, HashPtrToSeqNum);
269 InsertReleaseInst(Value *V, BasicBlock *BB,
270 Instruction *InsertBefore,
271 Function* ReleasePtrFunc) {
273 const Type *SBP = PointerType::get(Type::SByteTy);
274 if (V->getType() != SBP) // Cast pointer to be sbyte*
275 V = new CastInst(V, SBP, "RPSN_cast", InsertBefore);
277 vector<Value*> releaseArgs(1, V);
278 new CallInst(ReleasePtrFunc, releaseArgs, "", InsertBefore);
282 InsertRecordInst(Value *V, BasicBlock *BB,
283 Instruction *InsertBefore,
284 Function* RecordPtrFunc) {
285 const Type *SBP = PointerType::get(Type::SByteTy);
286 if (V->getType() != SBP) // Cast pointer to be sbyte*
287 V = new CastInst(V, SBP, "RP_cast", InsertBefore);
289 vector<Value*> releaseArgs(1, V);
290 new CallInst(RecordPtrFunc, releaseArgs, "", InsertBefore);
293 // Look for alloca and free instructions. These are the ptrs to release.
294 // Release the free'd pointers immediately. Record the alloca'd pointers
295 // to be released on return from the current function.
298 ReleasePtrSeqNumbers(BasicBlock *BB,
299 ExternalFuncs& externalFuncs) {
301 for (BasicBlock::iterator II=BB->begin(), IE = BB->end(); II != IE; ++II)
302 if (FreeInst *FI = dyn_cast<FreeInst>(II))
303 InsertReleaseInst(FI->getOperand(0), BB, FI,externalFuncs.ReleasePtrFunc);
304 else if (AllocaInst *AI = dyn_cast<AllocaInst>(II))
305 InsertRecordInst(AI, BB, AI->getNext(), externalFuncs.RecordPtrFunc);
309 // Insert print instructions at the end of basic block BB for each value
310 // computed in BB that is live at the end of BB,
311 // or that is stored to memory in BB.
312 // If the value is stored to memory, we load it back before printing it
313 // We also return all such loaded values in the vector valuesStoredInFunction
314 // for printing at the exit from the function. (Note that in each invocation
315 // of the function, this will only get the last value stored for each static
316 // store instruction).
318 static void TraceValuesAtBBExit(BasicBlock *BB,
319 Function *Printf, Function* HashPtrToSeqNum,
320 vector<Instruction*> *valuesStoredInFunction) {
321 // Get an iterator to point to the insertion location, which is
322 // just before the terminator instruction.
324 TerminatorInst *InsertPos = BB->getTerminator();
326 std::ostringstream OutStr;
327 WriteAsOperand(OutStr, BB, false);
328 InsertPrintInst(0, BB, InsertPos, "LEAVING BB:" + OutStr.str(),
329 Printf, HashPtrToSeqNum);
331 // Insert a print instruction for each instruction preceding InsertPos.
332 // The print instructions must go before InsertPos, so we use the
333 // instruction *preceding* InsertPos to check when to terminate the loop.
335 for (BasicBlock::iterator II = BB->begin(); &*II != InsertPos; ++II) {
336 if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
337 // Trace the stored value and address
338 InsertVerbosePrintInst(SI->getOperand(0), BB, InsertPos,
339 " (store value) ", Printf, HashPtrToSeqNum);
340 InsertVerbosePrintInst(SI->getOperand(1), BB, InsertPos,
341 " (store addr ) ", Printf, HashPtrToSeqNum);
343 else if (ShouldTraceValue(II))
344 InsertVerbosePrintInst(II, BB, InsertPos, " ", Printf, HashPtrToSeqNum);
348 static inline void InsertCodeToShowFunctionEntry(Function &F, Function *Printf,
349 Function* HashPtrToSeqNum){
350 // Get an iterator to point to the insertion location
351 BasicBlock &BB = F.getEntryBlock();
352 Instruction *InsertPos = BB.begin();
354 std::ostringstream OutStr;
355 WriteAsOperand(OutStr, &F);
356 InsertPrintInst(0, &BB, InsertPos, "ENTERING FUNCTION: " + OutStr.str(),
357 Printf, HashPtrToSeqNum);
359 // Now print all the incoming arguments
361 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++ArgNo){
362 InsertVerbosePrintInst(I, &BB, InsertPos,
363 " Arg #" + utostr(ArgNo) + ": ", Printf,
369 static inline void InsertCodeToShowFunctionExit(BasicBlock *BB,
371 Function* HashPtrToSeqNum) {
372 // Get an iterator to point to the insertion location
373 ReturnInst *Ret = cast<ReturnInst>(BB->getTerminator());
375 std::ostringstream OutStr;
376 WriteAsOperand(OutStr, BB->getParent(), true);
377 InsertPrintInst(0, BB, Ret, "LEAVING FUNCTION: " + OutStr.str(),
378 Printf, HashPtrToSeqNum);
380 // print the return value, if any
381 if (BB->getParent()->getReturnType() != Type::VoidTy)
382 InsertPrintInst(Ret->getReturnValue(), BB, Ret, " Returning: ",
383 Printf, HashPtrToSeqNum);
387 bool InsertTraceCode::runOnFunction(Function &F) {
388 if (!TraceThisFunction(F))
391 vector<Instruction*> valuesStoredInFunction;
392 vector<BasicBlock*> exitBlocks;
394 // Insert code to trace values at function entry
395 InsertCodeToShowFunctionEntry(F, externalFuncs.PrintfFunc,
396 externalFuncs.HashPtrFunc);
398 // Push a pointer set for recording alloca'd pointers at entry.
399 if (!DisablePtrHashing)
400 new CallInst(externalFuncs.PushOnEntryFunc, vector<Value*>(), "",
401 F.getEntryBlock().begin());
403 for (Function::iterator BB = F.begin(); BB != F.end(); ++BB) {
404 if (isa<ReturnInst>(BB->getTerminator()))
405 exitBlocks.push_back(BB); // record this as an exit block
407 // Insert trace code if this basic block is interesting...
408 handleBasicBlock(BB, valuesStoredInFunction);
410 if (!DisablePtrHashing) // release seq. numbers on free/ret
411 ReleasePtrSeqNumbers(BB, externalFuncs);
414 for (unsigned i=0; i != exitBlocks.size(); ++i)
416 // Insert code to trace values at function exit
417 InsertCodeToShowFunctionExit(exitBlocks[i], externalFuncs.PrintfFunc,
418 externalFuncs.HashPtrFunc);
420 // Release all recorded pointers before RETURN. Do this LAST!
421 if (!DisablePtrHashing)
422 new CallInst(externalFuncs.ReleaseOnReturnFunc, vector<Value*>(), "",
423 exitBlocks[i]->getTerminator());