Memory leak?

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1

Hi folk,

I get the following stack trace and do have any clue how to fix the problem.

0 opt 0x087ecc99
1 opt 0x087ed265
2 0xb7f6a400 __kernel_sigreturn + 0
3 opt 0x086d4198 llvm::LeakDetector::addGarbageObject(llvm::Value const*) + 29
4 opt 0x0872945f llvm::Instruction::Instruction(llvm::Type const*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*) + 109
5 opt 0x083d208b llvm::UnaryInstruction::UnaryInstruction(llvm::Type const*, unsigned int, llvm::Value*, llvm::Instruction*) + 75
6 opt 0x0873e46b llvm::CastInst::CastInst(llvm::Type const*, unsigned int, llvm::Value*, llvm::Twine const&, llvm::Instruction*) + 57
7 opt 0x0873124d llvm::BitCastInst::BitCastInst(llvm::Value*, llvm::Type const*, llvm::Twine const&, llvm::Instruction*) + 65

I insert extra two instructions to a byte code, the corresponding code is quite simple:
LoadInst* ptrVal = new LoadInst(ptr, “foobar”, false, next);
CastInst* ptrCast = new BitCastInst(ptrVal, charPtrType, “cast1”, next);

If I comment out the CastInst statement, it runs fine. Any hint what is wrong?
Thanks,
Neal

2

Hi folk,

I get the following stack trace and do have any clue how to fix the problem.

0 opt 0x087ecc99
1 opt 0x087ed265
2 0xb7f6a400 __kernel_sigreturn + 0
3 opt 0x086d4198
llvm::LeakDetector::addGarbageObject(llvm::Value const*) + 29
4 opt 0x0872945f llvm::Instruction::Instruction(llvm::Type
const*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*) + 109
5 opt 0x083d208b
llvm::UnaryInstruction::UnaryInstruction(llvm::Type const*, unsigned int,
llvm::Value*, llvm::Instruction*) + 75
6 opt 0x0873e46b llvm::CastInst::CastInst(llvm::Type const*,
unsigned int, llvm::Value*, llvm::Twine const&, llvm::Instruction*) + 57
7 opt 0x0873124d llvm::BitCastInst::BitCastInst(llvm::Value*,
llvm::Type const*, llvm::Twine const&, llvm::Instruction*) + 65

I insert extra two instructions to a byte code, the corresponding code is
quite simple:
LoadInst* ptrVal = new LoadInst(ptr, "foobar", false, next);
CastInst* ptrCast = new BitCastInst(ptrVal, charPtrType, "cast1", next);

If I comment out the CastInst statement, it runs fine. Any hint what is
wrong?

I have seen cases like this caused by a failure to destroy a pool
allocated object. Very small changes to the input cause the addresses
to change and it "works". What version of llvm are you using? If it is
current (svn), I think you will have to hunt the bug down with gdb.
Look for the same address being added as garbage twice for example.

Thanks,
Neal

Cheers,