ChiaLun
2013-Jan-07 02:38 UTC
[LLVMdev] Question on using GlobalVariable as function pointer
Hi everyone, I am trying to have an call instruction that calls global variable The first thing I do is gv = new llvm::GlobalVariable( *(tb->getModule()), fty, false,GlobalValue::InternalLinkage,0, "",0,0,0); fty : i32 ({ i32, [32 x i32] }*) I get stuck here, the fifth argument is the initializer which is a LLVM Constant, I do not know how to describe a function pointer as a constant. so currently, I just pass false to it. then I use myjit->getOrEmitGlobalVariable(gv); // myjit is LLVM ExecutionEngine but, I get an error LLVM ERROR: Could not resolve external global address However, when I modify fty to be an integer type or some primitive type, there is no error. Since LLVM demo page is closed, so I am not sure how to do it correctly. Have A Nice Day Chia Lun Liu -- View this message in context: http://llvm.1065342.n5.nabble.com/Question-on-using-GlobalVariable-as-function-pointer-tp53187.html Sent from the LLVM - Dev mailing list archive at Nabble.com.
Duncan Sands
2013-Jan-07 17:19 UTC
[LLVMdev] Question on using GlobalVariable as function pointer
Hi Chia Lun Liu, On 07/01/13 03:38, ChiaLun wrote:> Hi everyone, > > I am trying to have an call instruction that calls global variable > > > The first thing I do is > > gv = new llvm::GlobalVariable( *(tb->getModule()), > fty, > false,GlobalValue::InternalLinkage,0, > "",0,0,0); > > fty : i32 ({ i32, [32 x i32] }*) > > > I get stuck here, the fifth argument is the initializer which is a LLVM > Constant, > > I do not know how to describe a function pointer as a constant. > > so currently, I just pass false to it.If Func is the LLVM object of Function* type that represents the function you want to call, then you can use it as the initial value. The Function class derives from the GlobalValue class, and the GlobalValue class derives from the Constant class, thus anything of type Function* can be used wherever a Constant* is required. Ciao, Duncan.> > then I use > > myjit->getOrEmitGlobalVariable(gv); // myjit is LLVM ExecutionEngine> > > but, I get an error > > LLVM ERROR: Could not resolve external global address > > However, when I modify fty to be an integer type or some primitive type, > there is no error. > > Since LLVM demo page is closed, so I am not sure how to do it correctly. > > > Have A Nice Day > > Chia Lun Liu > > > > -- > View this message in context: http://llvm.1065342.n5.nabble.com/Question-on-using-GlobalVariable-as-function-pointer-tp53187.html > Sent from the LLVM - Dev mailing list archive at Nabble.com. > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >
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