-.. _lto:
-
======================================================
LLVM Link Time Optimization: Design and Implementation
======================================================
return foo1();
}
-.. code-block:: bash
+To compile, run:
+
+.. code-block:: console
- --- command lines ---
% clang -emit-llvm -c a.c -o a.o # <-- a.o is LLVM bitcode file
% clang -c main.c -o main.o # <-- main.o is native object file
% clang a.o main.o -o main # <-- standard link command without modifications
visible symbol defined in LLVM bitcode file. The linker completes its usual
symbol resolution pass and finds that ``foo2()`` is not used
anywhere. This information is used by the LLVM optimizer and it
- removes ``foo2()``.</li>
+ removes ``foo2()``.
* As soon as ``foo2()`` is removed, the optimizer recognizes that condition ``i
< 0`` is always false, which means ``foo3()`` is never used. Hence, the
Multi-phase communication between ``libLTO`` and linker
=======================================================
-The linker collects information about symbol defininitions and uses in various
+The linker collects information about symbol definitions and uses in various
link objects which is more accurate than any information collected by other
tools during typical build cycles. The linker collects this information by
looking at the definitions and uses of symbols in native .o files and using