Useful information for developing LLVM

[sun-jacobi]

FYI: https://github.com/sun-jacobi/llvm-script

[sun-jacobi]

Clang debugging

First run the command with -### to get the verbose version of the program.
Then simply lldb -- [VERBOSE COMMAND] .

Otherwise the child process created by clang would not be debugged

[sun-jacobi]

llc Debugging

Since llvm uses code generation, it is somewhat hard to use a debugger.
it is much more efficient to debug with the output.

Here are some useful options for dumping useful information.

Code Dump

--print-after-isel: show the result of Instruction Selection <- especially useful

DAG Dump

-view-dag-combine1-dags
-view-legalize-dags
-view-dag-combine2-dags
-view-isel-dags
-view-sched-dags

dump()

You still can use a debugger to check the local logic.
When using a debugger, dump() method for many classes is very useful.