[Question][Hw3]

[ee12ha0220]

What does "clang (filename).c (filename2).ll" do?

[RiceBiscuits]

Specified files (filename).c and (filename2.)ll will be compiled together.
If you want to know more thing about Clang, please check the link below.
(https://clang.llvm.org/docs/UsersManual.html)

[ee12ha0220]

I have searched the povided link, but there is no information about how .ll file is compiled by clang. Can you explain this part?

[KihongHeo]

Please take a look at https://github.com/prosyslab-classroom/llvm-primer.

[ee12ha0220]

I have checked the link already, but there is only information about creating .ll file using clang, not compiling .ll file with clang

[KihongHeo]

clang is a C compiler.
We use clang to create ll files from c files. The internal details of compilation are not a part of this homework.
Could you tell me why you need that one?

[ee12ha0220]

In the Makefile in the test folder, there is a line "$(CC) -o $* runtime.c $* .instrumented.ll".
So I was wondering what effect will "$* .instrumented.ll" give in compiling "runtime.c" with clang, in this situation.

[KihongHeo]

• runtime.c contains the runtime infrastructure for sanitizer
• X.ll is an intermediate representation (IR) of some X.c
• X.instrumented.ll should be the same as X.ll but with more instrumentation that uses functions in runtime.c
• clang X.instrumented.ll runtime.c will generate an instrumented executable file. The behavior of the exe file will be the same as that from clang X.ll or from clang X.c. But it has additional sanitization and linked with the sanitization functions.

[ee12ha0220]

Thank you :)