llvm-6502/lib/Transforms/Instrumentation/TraceValues.cpp
Jeff Cohen 66c5fd6c53 When a function takes a variable number of pointer arguments, with a zero
pointer marking the end of the list, the zero *must* be cast to the pointer
type.  An un-cast zero is a 32-bit int, and at least on x86_64, gcc will
not extend the zero to 64 bits, thus allowing the upper 32 bits to be
random junk.

The new END_WITH_NULL macro may be used to annotate a such a function
so that GCC (version 4 or newer) will detect the use of un-casted zero
at compile time.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23888 91177308-0d34-0410-b5e6-96231b3b80d8
2005-10-23 04:37:20 +00:00

438 lines
16 KiB
C++

//===- TraceValues.cpp - Value Tracing for debugging ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Support for inserting LLVM code to print values at basic block and function
// exits.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/ADT/StringExtras.h"
#include <algorithm>
#include <sstream>
using namespace llvm;
static cl::opt<bool>
DisablePtrHashing("tracedisablehashdisable", cl::Hidden,
cl::desc("Disable pointer hashing in the -trace or -tracem "
"passes"));
static cl::list<std::string>
TraceFuncNames("tracefunc", cl::desc("Only trace specific functions in the "
"-trace or -tracem passes"),
cl::value_desc("function"), cl::Hidden);
static void TraceValuesAtBBExit(BasicBlock *BB,
Function *Printf, Function* HashPtrToSeqNum,
std::vector<Instruction*> *valuesStoredInFunction);
// We trace a particular function if no functions to trace were specified
// or if the function is in the specified list.
//
inline static bool
TraceThisFunction(Function &F)
{
if (TraceFuncNames.empty()) return true;
return std::find(TraceFuncNames.begin(), TraceFuncNames.end(), F.getName())
!= TraceFuncNames.end();
}
namespace {
struct ExternalFuncs {
Function *PrintfFunc, *HashPtrFunc, *ReleasePtrFunc;
Function *RecordPtrFunc, *PushOnEntryFunc, *ReleaseOnReturnFunc;
void doInitialization(Module &M); // Add prototypes for external functions
};
class InsertTraceCode : public FunctionPass {
protected:
ExternalFuncs externalFuncs;
public:
// Add a prototype for runtime functions not already in the program.
//
bool doInitialization(Module &M);
//--------------------------------------------------------------------------
// Function InsertCodeToTraceValues
//
// Inserts tracing code for all live values at basic block and/or function
// exits as specified by `traceBasicBlockExits' and `traceFunctionExits'.
//
bool doit(Function *M);
virtual void handleBasicBlock(BasicBlock *BB,
std::vector<Instruction*> &VI) = 0;
// runOnFunction - This method does the work.
//
bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
}
};
struct FunctionTracer : public InsertTraceCode {
// Ignore basic blocks here...
virtual void handleBasicBlock(BasicBlock *BB,
std::vector<Instruction*> &VI) {}
};
struct BasicBlockTracer : public InsertTraceCode {
// Trace basic blocks here...
virtual void handleBasicBlock(BasicBlock *BB,
std::vector<Instruction*> &VI) {
TraceValuesAtBBExit(BB, externalFuncs.PrintfFunc,
externalFuncs.HashPtrFunc, &VI);
}
};
// Register the passes...
RegisterOpt<FunctionTracer> X("tracem","Insert Function trace code only");
RegisterOpt<BasicBlockTracer> Y("trace","Insert BB and Function trace code");
} // end anonymous namespace
/// Just trace functions
FunctionPass *llvm::createTraceValuesPassForFunction() {
return new FunctionTracer();
}
/// Trace BB's and functions
FunctionPass *llvm::createTraceValuesPassForBasicBlocks() {
return new BasicBlockTracer();
}
// Add a prototype for external functions used by the tracing code and require
// the trace library for this module.
//
void ExternalFuncs::doInitialization(Module &M) {
M.addLibrary("trace");
const Type *SBP = PointerType::get(Type::SByteTy);
const FunctionType *MTy =
FunctionType::get(Type::IntTy, std::vector<const Type*>(1, SBP), true);
PrintfFunc = M.getOrInsertFunction("printf", MTy);
// uint (sbyte*)
HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", Type::UIntTy, SBP,
(Type *)0);
// void (sbyte*)
ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum",
Type::VoidTy, SBP, (Type *)0);
RecordPtrFunc = M.getOrInsertFunction("RecordPointer",
Type::VoidTy, SBP, (Type *)0);
PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", Type::VoidTy,
(Type *)0);
ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
Type::VoidTy, (Type *)0);
}
// Add a prototype for external functions used by the tracing code.
//
bool InsertTraceCode::doInitialization(Module &M) {
externalFuncs.doInitialization(M);
return false;
}
static inline GlobalVariable *getStringRef(Module *M, const std::string &str) {
// Create a constant internal string reference...
Constant *Init = ConstantArray::get(str);
// Create the global variable and record it in the module
// The GV will be renamed to a unique name if needed.
GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
GlobalValue::InternalLinkage, Init,
"trstr");
M->getGlobalList().push_back(GV);
return GV;
}
//
// Check if this instruction has any uses outside its basic block,
// or if it used by either a Call or Return instruction (ditto).
// (Values stored to memory within this BB are live at end of BB but are
// traced at the store instruction, not where they are computed.)
//
static inline bool LiveAtBBExit(const Instruction* I) {
const BasicBlock *BB = I->getParent();
for (Value::use_const_iterator U = I->use_begin(); U != I->use_end(); ++U)
if (const Instruction *UI = dyn_cast<Instruction>(*U))
if (UI->getParent() != BB || isa<ReturnInst>(UI))
return true;
return false;
}
static inline bool TraceThisOpCode(unsigned opCode) {
// Explicitly test for opCodes *not* to trace so that any new opcodes will
// be traced by default (VoidTy's are already excluded)
//
return (opCode < Instruction::OtherOpsBegin &&
opCode != Instruction::Alloca &&
opCode != Instruction::PHI &&
opCode != Instruction::Cast);
}
// Trace a value computed by an instruction if it is non-void, it is computed
// by a real computation, not just a copy (see TraceThisOpCode), and
// -- it is a load instruction: we want to check values read from memory
// -- or it is live at exit from the basic block (i.e., ignore local temps)
//
static bool ShouldTraceValue(const Instruction *I) {
return
I->getType() != Type::VoidTy &&
TraceThisOpCode(I->getOpcode()) &&
(isa<LoadInst>(I) || LiveAtBBExit(I));
}
static std::string getPrintfCodeFor(const Value *V) {
if (V == 0) return "";
if (V->getType()->isFloatingPoint())
return "%g";
else if (V->getType() == Type::LabelTy)
return "0x%p";
else if (isa<PointerType>(V->getType()))
return DisablePtrHashing ? "0x%p" : "%d";
else if (V->getType()->isIntegral())
return "%d";
assert(0 && "Illegal value to print out...");
return "";
}
static void InsertPrintInst(Value *V, BasicBlock *BB, Instruction *InsertBefore,
std::string Message,
Function *Printf, Function* HashPtrToSeqNum) {
// Escape Message by replacing all % characters with %% chars.
std::string Tmp;
std::swap(Tmp, Message);
std::string::iterator I = std::find(Tmp.begin(), Tmp.end(), '%');
while (I != Tmp.end()) {
Message.append(Tmp.begin(), I);
Message += "%%";
++I; // Make sure to erase the % as well...
Tmp.erase(Tmp.begin(), I);
I = std::find(Tmp.begin(), Tmp.end(), '%');
}
Message += Tmp;
Module *Mod = BB->getParent()->getParent();
// Turn the marker string into a global variable...
GlobalVariable *fmtVal = getStringRef(Mod, Message+getPrintfCodeFor(V)+"\n");
// Turn the format string into an sbyte *
Constant *GEP=ConstantExpr::getGetElementPtr(fmtVal,
std::vector<Constant*>(2,Constant::getNullValue(Type::LongTy)));
// Insert a call to the hash function if this is a pointer value
if (V && isa<PointerType>(V->getType()) && !DisablePtrHashing) {
const Type *SBP = PointerType::get(Type::SByteTy);
if (V->getType() != SBP) // Cast pointer to be sbyte*
V = new CastInst(V, SBP, "Hash_cast", InsertBefore);
std::vector<Value*> HashArgs(1, V);
V = new CallInst(HashPtrToSeqNum, HashArgs, "ptrSeqNum", InsertBefore);
}
// Insert the first print instruction to print the string flag:
std::vector<Value*> PrintArgs;
PrintArgs.push_back(GEP);
if (V) PrintArgs.push_back(V);
new CallInst(Printf, PrintArgs, "trace", InsertBefore);
}
static void InsertVerbosePrintInst(Value *V, BasicBlock *BB,
Instruction *InsertBefore,
const std::string &Message, Function *Printf,
Function* HashPtrToSeqNum) {
std::ostringstream OutStr;
if (V) WriteAsOperand(OutStr, V);
InsertPrintInst(V, BB, InsertBefore, Message+OutStr.str()+" = ",
Printf, HashPtrToSeqNum);
}
static void
InsertReleaseInst(Value *V, BasicBlock *BB,
Instruction *InsertBefore,
Function* ReleasePtrFunc) {
const Type *SBP = PointerType::get(Type::SByteTy);
if (V->getType() != SBP) // Cast pointer to be sbyte*
V = new CastInst(V, SBP, "RPSN_cast", InsertBefore);
std::vector<Value*> releaseArgs(1, V);
new CallInst(ReleasePtrFunc, releaseArgs, "", InsertBefore);
}
static void
InsertRecordInst(Value *V, BasicBlock *BB,
Instruction *InsertBefore,
Function* RecordPtrFunc) {
const Type *SBP = PointerType::get(Type::SByteTy);
if (V->getType() != SBP) // Cast pointer to be sbyte*
V = new CastInst(V, SBP, "RP_cast", InsertBefore);
std::vector<Value*> releaseArgs(1, V);
new CallInst(RecordPtrFunc, releaseArgs, "", InsertBefore);
}
// Look for alloca and free instructions. These are the ptrs to release.
// Release the free'd pointers immediately. Record the alloca'd pointers
// to be released on return from the current function.
//
static void
ReleasePtrSeqNumbers(BasicBlock *BB,
ExternalFuncs& externalFuncs) {
for (BasicBlock::iterator II=BB->begin(), IE = BB->end(); II != IE; ++II)
if (FreeInst *FI = dyn_cast<FreeInst>(II))
InsertReleaseInst(FI->getOperand(0), BB, FI,externalFuncs.ReleasePtrFunc);
else if (AllocaInst *AI = dyn_cast<AllocaInst>(II))
InsertRecordInst(AI, BB, AI->getNext(), externalFuncs.RecordPtrFunc);
}
// Insert print instructions at the end of basic block BB for each value
// computed in BB that is live at the end of BB,
// or that is stored to memory in BB.
// If the value is stored to memory, we load it back before printing it
// We also return all such loaded values in the vector valuesStoredInFunction
// for printing at the exit from the function. (Note that in each invocation
// of the function, this will only get the last value stored for each static
// store instruction).
//
static void TraceValuesAtBBExit(BasicBlock *BB,
Function *Printf, Function* HashPtrToSeqNum,
std::vector<Instruction*> *valuesStoredInFunction) {
// Get an iterator to point to the insertion location, which is
// just before the terminator instruction.
//
TerminatorInst *InsertPos = BB->getTerminator();
std::ostringstream OutStr;
WriteAsOperand(OutStr, BB, false);
InsertPrintInst(0, BB, InsertPos, "LEAVING BB:" + OutStr.str(),
Printf, HashPtrToSeqNum);
// Insert a print instruction for each instruction preceding InsertPos.
// The print instructions must go before InsertPos, so we use the
// instruction *preceding* InsertPos to check when to terminate the loop.
//
for (BasicBlock::iterator II = BB->begin(); &*II != InsertPos; ++II) {
if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
// Trace the stored value and address
InsertVerbosePrintInst(SI->getOperand(0), BB, InsertPos,
" (store value) ", Printf, HashPtrToSeqNum);
InsertVerbosePrintInst(SI->getOperand(1), BB, InsertPos,
" (store addr ) ", Printf, HashPtrToSeqNum);
}
else if (ShouldTraceValue(II))
InsertVerbosePrintInst(II, BB, InsertPos, " ", Printf, HashPtrToSeqNum);
}
}
static inline void InsertCodeToShowFunctionEntry(Function &F, Function *Printf,
Function* HashPtrToSeqNum){
// Get an iterator to point to the insertion location
BasicBlock &BB = F.getEntryBlock();
Instruction *InsertPos = BB.begin();
std::ostringstream OutStr;
WriteAsOperand(OutStr, &F);
InsertPrintInst(0, &BB, InsertPos, "ENTERING FUNCTION: " + OutStr.str(),
Printf, HashPtrToSeqNum);
// Now print all the incoming arguments
unsigned ArgNo = 0;
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I, ++ArgNo){
InsertVerbosePrintInst(I, &BB, InsertPos,
" Arg #" + utostr(ArgNo) + ": ", Printf,
HashPtrToSeqNum);
}
}
static inline void InsertCodeToShowFunctionExit(BasicBlock *BB,
Function *Printf,
Function* HashPtrToSeqNum) {
// Get an iterator to point to the insertion location
ReturnInst *Ret = cast<ReturnInst>(BB->getTerminator());
std::ostringstream OutStr;
WriteAsOperand(OutStr, BB->getParent(), true);
InsertPrintInst(0, BB, Ret, "LEAVING FUNCTION: " + OutStr.str(),
Printf, HashPtrToSeqNum);
// print the return value, if any
if (BB->getParent()->getReturnType() != Type::VoidTy)
InsertPrintInst(Ret->getReturnValue(), BB, Ret, " Returning: ",
Printf, HashPtrToSeqNum);
}
bool InsertTraceCode::runOnFunction(Function &F) {
if (!TraceThisFunction(F))
return false;
std::vector<Instruction*> valuesStoredInFunction;
std::vector<BasicBlock*> exitBlocks;
// Insert code to trace values at function entry
InsertCodeToShowFunctionEntry(F, externalFuncs.PrintfFunc,
externalFuncs.HashPtrFunc);
// Push a pointer set for recording alloca'd pointers at entry.
if (!DisablePtrHashing)
new CallInst(externalFuncs.PushOnEntryFunc, std::vector<Value*>(), "",
F.getEntryBlock().begin());
for (Function::iterator BB = F.begin(); BB != F.end(); ++BB) {
if (isa<ReturnInst>(BB->getTerminator()))
exitBlocks.push_back(BB); // record this as an exit block
// Insert trace code if this basic block is interesting...
handleBasicBlock(BB, valuesStoredInFunction);
if (!DisablePtrHashing) // release seq. numbers on free/ret
ReleasePtrSeqNumbers(BB, externalFuncs);
}
for (unsigned i=0; i != exitBlocks.size(); ++i)
{
// Insert code to trace values at function exit
InsertCodeToShowFunctionExit(exitBlocks[i], externalFuncs.PrintfFunc,
externalFuncs.HashPtrFunc);
// Release all recorded pointers before RETURN. Do this LAST!
if (!DisablePtrHashing)
new CallInst(externalFuncs.ReleaseOnReturnFunc, std::vector<Value*>(),
"", exitBlocks[i]->getTerminator());
}
return true;
}