[LLVMdev] bytecode reader assertion failure

[Reid Spencer]

Ryan,

This looks like a bug. Could you file it, please?

Reid.

On Thu, 2007-02-22 at 19:47 -0600, Ryan M. Lefever wrote:
> I have a compiler transform that I have been working on that produces 
> bytecode that passes the verifier.  However, when I try to read that 
> bytecode back in, I get the assertion failure below.
> 
> llvm::BytecodeReader::ParseConstantPoolValue(unsigned int):
> Assertion `(!isa<Constant>(Result) || 
> !cast<Constant>(Result)->isNullValue()) || !hasImplicitNull(TypeID) && 
> "Cannot read null values from bytecode!"' failed.
> 
> So, I ran gdb on opt.  I was able to get the following information from opt:
> 
> (gdb) print Result
> $7 = (class llvm::Constant *) 0x96ad9d0
> (gdb) call Result->dump()
>   [41 x sbyte *] zeroinitializer
> (gdb) print hasImplicitNull(TypeID)
> $5 = true
> 
> Does anyone have any insight into what the problem is or how to go about 
>   fixing it?  It seems diffcult to get context for what is going on, 
> since the bytecode has not yet been fully read.  Any help would be 
> greatly appreciated!
> 
> The full output of the assertion failure is given below:
> 
> opt -simplifycfg -deadargelim -globaldce -verify -f -o /dev/null tmp.bc
> opt: Reader.cpp:1978: llvm::Value* 
> llvm::BytecodeReader::ParseConstantPoolValue(unsigned int): Assertion 
> `(!isa<Constant>(Result) || !cast<Constant>(Result)->isNullValue()) || 
> !hasImplicitNull(TypeID) && "Cannot read null values from bytecode!"' 
> failed.
> opt((anonymous namespace)::PrintStackTrace()+0x1a)[0x8645bae]
> opt((anonymous namespace)::SignalHandler(int)+0x112)[0x8645e74]
> [0xb87420]
> /lib/libc.so.6(abort+0x101)[0x4cab64f1]
> /lib/libc.so.6(__assert_fail+0xfd)[0x4caae859]
> opt(llvm::BytecodeReader::ParseConstantPoolValue(unsigned 
> int)+0x1b31)[0x856e825]
> opt(llvm::BytecodeReader::ParseConstantPool(std::vector<llvm::BytecodeReader::ValueList*, 
> std::allocator<llvm::BytecodeReader::ValueList*> >&, 
> std::vector<llvm::PATypeHolder, std::allocator<llvm::PATypeHolder> >&, 
> bool)+0x147)[0x856e985]
> opt(llvm::BytecodeReader::ParseModule()+0x188)[0x856edfe]
> opt(llvm::BytecodeReader::ParseBytecode(unsigned char const*, unsigned 
> int, std::basic_string<char, std::char_traits<char>, 
> std::allocator<char> > const&, std::basic_string<char, 
> std::char_traits<char>, std::allocator<char> >*)+0x539)[0x856f6c1]
> opt((anonymous 
> namespace)::BytecodeFileReader::read(std::basic_string<char, 
> std::char_traits<char>, std::allocator<char> >*)+0xeb)[0x855b569]
> opt(llvm::getBytecodeModuleProvider(std::basic_string<char, 
> std::char_traits<char>, std::allocator<char> > const&, 
> std::basic_string<char, std::char_traits<char>, std::allocator<char> >*, 
> llvm::BytecodeHandler*)+0x93)[0x855b60b]
> opt(llvm::ParseBytecodeFile(std::basic_string<char, 
> std::char_traits<char>, std::allocator<char> > const&, 
> std::basic_string<char, std::char_traits<char>, std::allocator<char> 
>  >*)+0x20)[0x855b88e]
> opt(main+0x7e)[0x8378c90]
> /lib/libc.so.6(__libc_start_main+0xdc)[0x4caa24e4]
> opt(__gxx_personality_v0+0x149)[0x836bac1]
> 
> 
> Regards,
> Ryan
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