[LLVMdev] context/scope of instruction

[Christian Jacobs]

Am 20.01.2012 19:36, schrieb Christian Jacobs:
>
> Am 20.01.2012 um 18:12 schrieb Devang Patel:
>
>>
>> On Jan 19, 2012, at 10:12 AM, Christian Jacobs wrote:
>>
>>> Hello,
>>> I need to know how I get the LLVM::IDScope object of an instruction.
>>>
>>> My program contains:
>>> call void (...)* @commit(), !dbg !16
>>>
>>> !16 = metadata !{i32 16, i32 5, metadata !8, null}
>>>
>>> !8 = metadata !{i32 589835, metadata !4, i32 10, i32 1, metadata !2, i32 0} ; [ DW_TAG_lexical_block ]
>>>
>>
>> !8 is DIScope here (actually it is DILexicalBlock, which is derived from DIScope).
>
> I know. I am writing an LLVM pass and I do not know how I get a hand on the DIScope object.
> Which method(s) of the LLVM C++ API do I have to call to get a pointer or reference (!8) to the LLVM::DIScope of an LLVM::Instruction?
>
> Christian
>
I found a solution.
MDNode *node = inst.getMetadata(LLVMContext::MD_dbg);
DIDescriptor descriptor(cast<MDNode>(node->getOperand((unsigned)2)));
assert(descriptor.isScope());
DIScope scope(descriptor);

This article was very helpful:
http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html

Christian