[lldb-dev] invalid LLVMContext during expression evaluation

[Malea, Daniel]

Hi Sean/list,

I have just started looking into a problem that's happening with the Debian test runs (but interestingly not under manual configure/cmake builds) where the LLVMContext is coming up as uninitialized, thereby causing the internal LLDB segfault in the following stack trace. Any hints where I should start digging for the root-cause? I imagine LLDB attempts to use a global LLVMContext (?), but I have not yet found the code that initializes it...


Thanks,
Dan

Trace:

Program received signal SIGSEGV, Segmentation fault.
llvm::Value::getContext (this=0x10ea950) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/lib/IR/Value.cpp:480
480 LLVMContext &Value::getContext() const { return VTy->getContext(); }
(gdb) bt
#0  llvm::Value::getContext (this=0x10ea950) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/lib/IR/Value.cpp:480
#1  0x00007ffff387a99e in llvm::ValueHandleBase::AddToUseList (this=0x116c7d0) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/lib/IR/Value.cpp:515
#2  0x00007ffff385c8e3 in ValueHandleBase (V=<optimized out>, Kind=llvm::ValueHandleBase::Callback, this=0x116c7d0) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/include/llvm/Support/ValueHandle.h:71
#3  CallbackVH (P=<optimized out>, this=0x116c7c8) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/include/llvm/Support/ValueHandle.h:354
#4  MDNodeOperand (V=<optimized out>, this=0x116c7c8) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/lib/IR/Metadata.cpp:67
#5  llvm::MDNode::MDNode (this=<optimized out>, C=..., Vals=..., isFunctionLocal=<optimized out>) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/lib/IR/Metadata.cpp:122
#6  0x00007ffff385ca47 in llvm::MDNode::getMDNode (Context=..., Vals=..., FL=<optimized out>, Insert=<optimized out>) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/lib/IR/Metadata.cpp:255
#7  0x00007ffff4cf7de9 in IRForTarget::RegisterFunctionMetadata (this=this at entry=0x7fffffffadb0, context=..., function_ptr=function_ptr at entry=0x10b7690, name=0x1139cc0 "_ZL18a_function_to_callv")
    at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/tools/lldb/source/Expression/IRForTarget.cpp:344
#8  0x00007ffff4cf86e1 in IRForTarget::ResolveFunctionPointers (this=this at entry=0x7fffffffadb0, llvm_module=..., llvm_function=...) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/tools/lldb/source/Expression/IRForTarget.cpp:390
#9  0x00007ffff4cff3d8 in IRForTarget::runOnModule (this=0x7fffffffadb0, llvm_module=...) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/tools/lldb/source/Expression/IRForTarget.cpp:2755
#10 0x00007ffff4ce3b12 in lldb_private::ClangExpressionParser::PrepareForExecution (this=0x7fffffffaf60, func_addr=@0x10c2398: 18446744073709551615, func_end=@0x10c23a0: 18446744073709551615, execution_unit_ap=..., exe_ctx=..., can_interpret=@0x10c2438: false,
    execution_policy=lldb_private::eExecutionPolicyOnlyWhenNeeded) at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/tools/lldb/source/Expression/ClangExpressionParser.cpp:525
#11 0x00007ffff4cebfc7 in lldb_private::ClangUserExpression::Parse (this=0x10c2380, error_stream=..., exe_ctx=..., execution_policy=execution_policy at entry=lldb_private::eExecutionPolicyOnlyWhenNeeded, keep_result_in_memory=keep_result_in_memory at entry=true)
    at /home/daniel/dev/llvm-toolchain-snapshots-automake/llvm-toolchain-snapshot-3.4~svn182852/tools/lldb/source/Expression/ClangUserExpression.cpp:524