[ICE] extern(C) struct with ctor and field

[MartinNowak]

module bug;
extern(C):

struct Value
{
    this(string) {}
    string s;
}

ldc2 -c bug.d

Incompatible argument and return types for 'returned' attribute
{ i64, i64 } (%bug.Value_, { i64, i8_ })* @D3bug5Value6__ctorMUNcAyaZS3bug5Value
Broken module found, compilation aborted!
0 ldc2 0x000000000115b1d2 llvm::sys::PrintStackTrace(IO_FILE) + 34
1 ldc2 0x000000000115a781
2 libpthread.so.0 0x00007f7214e13750
3 libc.so.6 0x00007f7214051c39 gsignal + 57
4 libc.so.6 0x00007f7214053348 abort + 328
5 ldc2 0x000000000111dc3b
6 ldc2 0x00000000010f2f6c llvm::FPPassManager::runOnFunction(llvm::Function&) + 540
7 ldc2 0x00000000010f300b llvm::FPPassManager::runOnModule(llvm::Module&) + 43
8 ldc2 0x00000000010f2bbc llvm::legacy::PassManagerImpl::run(llvm::Module&) + 748
9 ldc2 0x000000000111ba71 llvm::verifyModule(llvm::Module const&, llvm::VerifierFailureAction, std::string) + 913
10 ldc2 0x00000000006a206c Module::genLLVMModule(llvm::LLVMContext&) + 1724
11 ldc2 0x000000000055c898 main + 6200
12 libc.so.6 0x00007f721403dd65 __libc_start_main + 245
13 ldc2 0x000000000057566d

[dnadlinger]

This is with a release build of LLVM, right?

Quite probably, we are generating invalid IR somewhere, which should be easy to catch with a debug build of LLVM. Unfortunately, I can't check this right now, as I am not at my dev machine.

[MartinNowak]

This is with a release build of LLVM, right?

Sorry, should have written that. It happens on both 0.12.1 and 0.13.0-beta1.

[dnadlinger]

Okay, thanks – we indeed build those against an LLVM build with assertions disabled.

[redstar]

I get the assertion, too.

I think the root cause is incompatible types but I still need to check this.

[redstar]

I added the returned attribute to the code generator. This is a hint to LLVM that the parameter marked with this attribute is returned as function result. This should be the case for ctors.
It looks that in this example the LLVM type of this is Value but the type of the return value is Value * which triggers the assertion.

[redstar]

This quick fix is disable adding the returned attribute.

[MartinNowak]

Thanks for the quick fix.

[redstar]

Well, it was easy to prevent the crash. But now there is an unused optimization opportunity...