[LLVMdev] static constant structs (original) (raw)

Duncan Sands baldrick at free.fr
Mon Jul 23 08:25:54 PDT 2012

Hi Michael,

I hope this is the correct forum in which to ask this question.

Currently I am writing code meant to compile with LLVM 3.0. I am trying to figure out, using the C++ API, how to create a constant static struct, or the equivalent. Since I am copying data from existing C structs, I am currently I am using a ConstantArray global variable, and then pointer casting it to the appropriate type when I use it, but this seems overly clunky. Constant *cip = ConstantArray::get( ctx(), StringRef((char *)&addr, sizeof(addr)), false); return new GlobalVariable( *mod(), cip->getType(), true, GlobalVariable::PrivateLinkage, cip); In a previous version of my code, I replaced cip->getType() with the llvm equivalent of the type of addr. This worked until I tried with a build of llvm that had assertions turned on. Even without that, I am hoping there is a better way to do this that I have managed to overlook.

I'm not sure I understood your question, but it sounds like you may want to call this ConstantArray method (with AddNull = false).

/// This method constructs a ConstantArray and initializes it with a text /// string. The default behavior (AddNull==true) causes a null terminator to /// be placed at the end of the array. This effectively increases the length /// of the array by one (you've been warned). However, in some situations /// this is not desired so if AddNull==false then the string is copied without /// null termination. static Constant *get(LLVMContext &Context, StringRef Initializer, bool AddNull = true);

Ciao, Duncan.

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