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.
123 void ExternalFuncs::doInitialization(Module &M) {
124 const Type *SBP = PointerType::get(Type::SByteTy);
125 const FunctionType *MTy =
126 FunctionType::get(Type::IntTy, std::vector<const Type*>(1, SBP), true);
127 PrintfFunc = M.getOrInsertFunction("printf", MTy);
130 HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", Type::UIntTy, SBP,
134 ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum",
135 Type::VoidTy, SBP, 0);
136 RecordPtrFunc = M.getOrInsertFunction("RecordPointer",
137 Type::VoidTy, SBP, 0);
139 PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", Type::VoidTy, 0);
140 ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
145 // Add a prototype for external functions used by the tracing code.
147 bool InsertTraceCode::doInitialization(Module &M) {
148 externalFuncs.doInitialization(M);
153 static inline GlobalVariable *getStringRef(Module *M, const std::string &str) {
154 // Create a constant internal string reference...
155 Constant *Init = ConstantArray::get(str);
157 // Create the global variable and record it in the module
158 // The GV will be renamed to a unique name if needed.
159 GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
160 GlobalValue::InternalLinkage, Init,
162 M->getGlobalList().push_back(GV);
168 // Check if this instruction has any uses outside its basic block,
169 // or if it used by either a Call or Return instruction (ditto).
170 // (Values stored to memory within this BB are live at end of BB but are
171 // traced at the store instruction, not where they are computed.)
173 static inline bool LiveAtBBExit(const Instruction* I) {
174 const BasicBlock *BB = I->getParent();
175 for (Value::use_const_iterator U = I->use_begin(); U != I->use_end(); ++U)
176 if (const Instruction *UI = dyn_cast<Instruction>(*U))
177 if (UI->getParent() != BB || isa<ReturnInst>(UI))
184 static inline bool TraceThisOpCode(unsigned opCode) {
185 // Explicitly test for opCodes *not* to trace so that any new opcodes will
186 // be traced by default (VoidTy's are already excluded)
188 return (opCode < Instruction::OtherOpsBegin &&
189 opCode != Instruction::Alloca &&
190 opCode != Instruction::PHI &&
191 opCode != Instruction::Cast);
195 // Trace a value computed by an instruction if it is non-void, it is computed
196 // by a real computation, not just a copy (see TraceThisOpCode), and
197 // -- it is a load instruction: we want to check values read from memory
198 // -- or it is live at exit from the basic block (i.e., ignore local temps)
200 static bool ShouldTraceValue(const Instruction *I) {
202 I->getType() != Type::VoidTy &&
203 TraceThisOpCode(I->getOpcode()) &&
204 (isa<LoadInst>(I) || LiveAtBBExit(I));
207 static std::string getPrintfCodeFor(const Value *V) {
208 if (V == 0) return "";
209 if (V->getType()->isFloatingPoint())
211 else if (V->getType() == Type::LabelTy)
213 else if (isa<PointerType>(V->getType()))
214 return DisablePtrHashing ? "0x%p" : "%d";
215 else if (V->getType()->isIntegral())
218 assert(0 && "Illegal value to print out...");
223 static void InsertPrintInst(Value *V, BasicBlock *BB, Instruction *InsertBefore,
225 Function *Printf, Function* HashPtrToSeqNum) {
226 // Escape Message by replacing all % characters with %% chars.
228 std::swap(Tmp, Message);
229 std::string::iterator I = std::find(Tmp.begin(), Tmp.end(), '%');
230 while (I != Tmp.end()) {
231 Message.append(Tmp.begin(), I);
233 ++I; // Make sure to erase the % as well...
234 Tmp.erase(Tmp.begin(), I);
235 I = std::find(Tmp.begin(), Tmp.end(), '%');
238 Module *Mod = BB->getParent()->getParent();
240 // Turn the marker string into a global variable...
241 GlobalVariable *fmtVal = getStringRef(Mod, Message+getPrintfCodeFor(V)+"\n");
243 // Turn the format string into an sbyte *
244 Constant *GEP=ConstantExpr::getGetElementPtr(fmtVal,
245 std::vector<Constant*>(2,Constant::getNullValue(Type::LongTy)));
247 // Insert a call to the hash function if this is a pointer value
248 if (V && isa<PointerType>(V->getType()) && !DisablePtrHashing) {
249 const Type *SBP = PointerType::get(Type::SByteTy);
250 if (V->getType() != SBP) // Cast pointer to be sbyte*
251 V = new CastInst(V, SBP, "Hash_cast", InsertBefore);
253 std::vector<Value*> HashArgs(1, V);
254 V = new CallInst(HashPtrToSeqNum, HashArgs, "ptrSeqNum", InsertBefore);
257 // Insert the first print instruction to print the string flag:
258 std::vector<Value*> PrintArgs;
259 PrintArgs.push_back(GEP);
260 if (V) PrintArgs.push_back(V);
261 new CallInst(Printf, PrintArgs, "trace", InsertBefore);
265 static void InsertVerbosePrintInst(Value *V, BasicBlock *BB,
266 Instruction *InsertBefore,
267 const std::string &Message, Function *Printf,
268 Function* HashPtrToSeqNum) {
269 std::ostringstream OutStr;
270 if (V) WriteAsOperand(OutStr, V);
271 InsertPrintInst(V, BB, InsertBefore, Message+OutStr.str()+" = ",
272 Printf, HashPtrToSeqNum);
276 InsertReleaseInst(Value *V, BasicBlock *BB,
277 Instruction *InsertBefore,
278 Function* ReleasePtrFunc) {
280 const Type *SBP = PointerType::get(Type::SByteTy);
281 if (V->getType() != SBP) // Cast pointer to be sbyte*
282 V = new CastInst(V, SBP, "RPSN_cast", InsertBefore);
284 std::vector<Value*> releaseArgs(1, V);
285 new CallInst(ReleasePtrFunc, releaseArgs, "", InsertBefore);
289 InsertRecordInst(Value *V, BasicBlock *BB,
290 Instruction *InsertBefore,
291 Function* RecordPtrFunc) {
292 const Type *SBP = PointerType::get(Type::SByteTy);
293 if (V->getType() != SBP) // Cast pointer to be sbyte*
294 V = new CastInst(V, SBP, "RP_cast", InsertBefore);
296 std::vector<Value*> releaseArgs(1, V);
297 new CallInst(RecordPtrFunc, releaseArgs, "", InsertBefore);
300 // Look for alloca and free instructions. These are the ptrs to release.
301 // Release the free'd pointers immediately. Record the alloca'd pointers
302 // to be released on return from the current function.
305 ReleasePtrSeqNumbers(BasicBlock *BB,
306 ExternalFuncs& externalFuncs) {
308 for (BasicBlock::iterator II=BB->begin(), IE = BB->end(); II != IE; ++II)
309 if (FreeInst *FI = dyn_cast<FreeInst>(II))
310 InsertReleaseInst(FI->getOperand(0), BB, FI,externalFuncs.ReleasePtrFunc);
311 else if (AllocaInst *AI = dyn_cast<AllocaInst>(II))
312 InsertRecordInst(AI, BB, AI->getNext(), externalFuncs.RecordPtrFunc);
316 // Insert print instructions at the end of basic block BB for each value
317 // computed in BB that is live at the end of BB,
318 // or that is stored to memory in BB.
319 // If the value is stored to memory, we load it back before printing it
320 // We also return all such loaded values in the vector valuesStoredInFunction
321 // for printing at the exit from the function. (Note that in each invocation
322 // of the function, this will only get the last value stored for each static
323 // store instruction).
325 static void TraceValuesAtBBExit(BasicBlock *BB,
326 Function *Printf, Function* HashPtrToSeqNum,
327 std::vector<Instruction*> *valuesStoredInFunction) {
328 // Get an iterator to point to the insertion location, which is
329 // just before the terminator instruction.
331 TerminatorInst *InsertPos = BB->getTerminator();
333 std::ostringstream OutStr;
334 WriteAsOperand(OutStr, BB, false);
335 InsertPrintInst(0, BB, InsertPos, "LEAVING BB:" + OutStr.str(),
336 Printf, HashPtrToSeqNum);
338 // Insert a print instruction for each instruction preceding InsertPos.
339 // The print instructions must go before InsertPos, so we use the
340 // instruction *preceding* InsertPos to check when to terminate the loop.
342 for (BasicBlock::iterator II = BB->begin(); &*II != InsertPos; ++II) {
343 if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
344 // Trace the stored value and address
345 InsertVerbosePrintInst(SI->getOperand(0), BB, InsertPos,
346 " (store value) ", Printf, HashPtrToSeqNum);
347 InsertVerbosePrintInst(SI->getOperand(1), BB, InsertPos,
348 " (store addr ) ", Printf, HashPtrToSeqNum);
350 else if (ShouldTraceValue(II))
351 InsertVerbosePrintInst(II, BB, InsertPos, " ", Printf, HashPtrToSeqNum);
355 static inline void InsertCodeToShowFunctionEntry(Function &F, Function *Printf,
356 Function* HashPtrToSeqNum){
357 // Get an iterator to point to the insertion location
358 BasicBlock &BB = F.getEntryBlock();
359 Instruction *InsertPos = BB.begin();
361 std::ostringstream OutStr;
362 WriteAsOperand(OutStr, &F);
363 InsertPrintInst(0, &BB, InsertPos, "ENTERING FUNCTION: " + OutStr.str(),
364 Printf, HashPtrToSeqNum);
366 // Now print all the incoming arguments
368 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++ArgNo){
369 InsertVerbosePrintInst(I, &BB, InsertPos,
370 " Arg #" + utostr(ArgNo) + ": ", Printf,
376 static inline void InsertCodeToShowFunctionExit(BasicBlock *BB,
378 Function* HashPtrToSeqNum) {
379 // Get an iterator to point to the insertion location
380 ReturnInst *Ret = cast<ReturnInst>(BB->getTerminator());
382 std::ostringstream OutStr;
383 WriteAsOperand(OutStr, BB->getParent(), true);
384 InsertPrintInst(0, BB, Ret, "LEAVING FUNCTION: " + OutStr.str(),
385 Printf, HashPtrToSeqNum);
387 // print the return value, if any
388 if (BB->getParent()->getReturnType() != Type::VoidTy)
389 InsertPrintInst(Ret->getReturnValue(), BB, Ret, " Returning: ",
390 Printf, HashPtrToSeqNum);
394 bool InsertTraceCode::runOnFunction(Function &F) {
395 if (!TraceThisFunction(F))
398 std::vector<Instruction*> valuesStoredInFunction;
399 std::vector<BasicBlock*> exitBlocks;
401 // Insert code to trace values at function entry
402 InsertCodeToShowFunctionEntry(F, externalFuncs.PrintfFunc,
403 externalFuncs.HashPtrFunc);
405 // Push a pointer set for recording alloca'd pointers at entry.
406 if (!DisablePtrHashing)
407 new CallInst(externalFuncs.PushOnEntryFunc, std::vector<Value*>(), "",
408 F.getEntryBlock().begin());
410 for (Function::iterator BB = F.begin(); BB != F.end(); ++BB) {
411 if (isa<ReturnInst>(BB->getTerminator()))
412 exitBlocks.push_back(BB); // record this as an exit block
414 // Insert trace code if this basic block is interesting...
415 handleBasicBlock(BB, valuesStoredInFunction);
417 if (!DisablePtrHashing) // release seq. numbers on free/ret
418 ReleasePtrSeqNumbers(BB, externalFuncs);
421 for (unsigned i=0; i != exitBlocks.size(); ++i)
423 // Insert code to trace values at function exit
424 InsertCodeToShowFunctionExit(exitBlocks[i], externalFuncs.PrintfFunc,
425 externalFuncs.HashPtrFunc);
427 // Release all recorded pointers before RETURN. Do this LAST!
428 if (!DisablePtrHashing)
429 new CallInst(externalFuncs.ReleaseOnReturnFunc, std::vector<Value*>(),
430 "", exitBlocks[i]->getTerminator());