问题
I'm not sure how to create a ConstantInt in LLVM- I know the number I would like to create, but I'm unsure how I can make a ConstantInt representing that number; I can't seem to find the constructor I need in the documentation.
I'm thinking it has to be along the lines of
ConstantInt consVal = new ConstantInt(something here).
I know I want it to be an int type, and I know my value... I just want to create a number!
回答1:
Most things in LLVM are created through a static method call instead of directly using a constructor. One reason is that an existing object can be returned instead of creating a new instance.
The static members of ConstantInt have a number of creation methods. You're probably most interested in get (Type *Ty, uint64_t V, bool isSigned=false) and, if you don't already have an integer type, IntegerType::get (LLVMContext &C, unsigned NumBits).
回答2:
To make an a 32 bit integer:
llvm::ConstantInt::get(context, llvm::APInt(/*nbits*/32, value, /*bool*/is_signed));
回答3:
To create a 32-bit integer constant:
llvm::Type *i32_type = llvm::IntegerType::getInt32Ty(llvm_context);
llvm::Constant *i32_val = llvm::ConstantInt::get(i32_type, -1/*value*/, true);
回答4:
ConstantInt* const_int32 = ConstantInt::get( Context , APInt(32, StringRef("10"), 10));
where, APInt(32, StringRef("10"), 10); gets int value from string "10" with base 10.
来源：https://stackoverflow.com/questions/16246920/how-to-create-a-constantint-in-llvm