context/scope of instruction

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#1

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 ]

LLVM::Instruction.hasMetadata() is 0

I got LLVM::Scope for variables over DIGlobalVariable.getContext() and DIVariable.getContext() but how do I get it for instructions?

Regards
Christian Jacobs

#2

!8 is DIScope here (actually it is DILexicalBlock, which is derived from DIScope).

#3

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

#4

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