[LLVMdev] Inserting a function call into bitcode

Nehal Gandhi nbg2k7 at gmail.com
Fri Jun 4 00:09:28 PDT 2010

On Thu, Jun 3, 2010 at 10:45 PM, Nehal Gandhi <nbg2k7 at gmail.com> wrote:
>> Hi Eli,
>> Thanks for that. Rookie mistake on my side. It solves the linking issue.
>> However, it was not the main problem. The problem is when I execute the
>> linked file ( modified bitcode + file containing the function), I get an
>> assertion error - Assertion `Addr && "Code generation didn't add function
>> GlobalAddress table!"' failed.
>> So my main concern - is that a correct way to insert a call instruction
>> the bitcode the way I did? The same code for inserting a function call
>> instruction works correctly with LLVM2.5 .
>My best guess is that you're doing something wrong invoking the JIT;
>there isn't anything obviously wrong with the code from your original

Well I am just using lli to run the linked file (i.e. program.bc). The
command chain is usually as follows.

	llvm-g++ --emit-llvm -c PrintRes.cpp -o PrintRes.bc
	(PrintRes.bc has the function which I want to call from the
newfile.bc below)

	opt -load ../../../Release/lib/CondPass.so -ProfileCond < try.bc >
      (this generates newfile.bc while try.bc is original code)

	llvm-link -o program.bc newfile.bc PrintRes.bc 
	lli program.bc

where newfile.bc is the bitcode generated by pass and PrintRes.bcis the file
that contains the function I am inserting using pass. Actually, program.bc
starts running. But when it encounters call instruction for that function,
it gives above assertion failure. The confusing thing how the same stuff
works perfectly in LLVM2.5. It is preventing me porting a quite bigger pass
(with lots of function calls and analysis part) from 2.5 to 2.6.

- Nehal.

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