Add Familiarizing with LLVM section.

diff --git a/Report/Main/Problems/Challenges.tex b/Report/Main/Problems/Challenges.tex
index 2787650340c41006f9c6d577a4002947e919a2ea..873e2e9f52063c5ba67a086edafd184678a84051 100644 (file)
--- a/Report/Main/Problems/Challenges.tex
+++ b/Report/Main/Problems/Challenges.tex
@@ -87,8 +87,48 @@ being succesfully implemented. This is conforming to the incremental development
 of MontiumC that was envisioned at the outset of its development.
 
 \subsection{Familiarizing with LLVM}
 of MontiumC that was envisioned at the outset of its development.
 
 \subsection{Familiarizing with LLVM}

-This section says something about integrating in the LLVM community as well as
-getting acquainted with the code.
+Since during my internship I have been working mainly with LLVM (code), one of
+the first challenges was to get myself familiar with LLVM. There are two main
+aspects to this: Getting to know my way around the LLVM codebase and getting to
+know the LLVM community.
+
+Since LLVM has a pretty large amount of documentation, I spent most of my first
+weeks with reading tutorials and documents. Since there was already a (very
+preliminary) version of the clang-based frontend, I also had some code to play
+with.
+
+During this period, it was not completely clear what the frontend should
+be doing and what transformations should be written. To prevent circular
+dependencies in my tasks (I can't write any code before I know what needs to be
+written, but I can't really tell what's needed until I know how the code works,
+which I can't effectively learn without actively working with it, etc.) I
+started out with adapting the loop unrolling pass in LLVM to be better suited to
+the Montium architecture. Eventually, this code didn't turn out to be
+immediately useful (it's still not included currently), but it proved very
+insightful as to how the LLVM framework is built and what its possibilities are.
+
+Additionally, during my working with the code in this stage I also produced a
+number of patches for LLVM, containing bugfixes, some cleanup and documentation
+improvements. Since the best way to integrate with any open source project seems
+to be contributing code, I was giving commit access to the LLVM tree not long
+thereafter. This access has proved very useful during the rest of the
+internship, since it was now a a lot easier to make (simple) changes to the LLVM
+framework to better suit the needs of Recore.
+
+A major challenge during my internship was to find the balance between doing
+work specifically for Recore, and doing work that is useful for LLVM in general.
+Any tasks that are required by the Montium frontend and the LLVM changes they
+directly need are obvious. However, usually when making changes to the main LLVM
+code, just changing enough for Recore is not engough for LLVM. Since the LLVM
+code must work on any program, not just MontiumC programs, extra changes are
+required. This is also an issue of building up credit within the LLVM community:
+The more you contribute to LLVM, the more influence you have when things need
+changing. Lastly, this is also a matter of efficiency: If I have been working
+with a particular piece of code intensively, it is more efficient for me to fix
+a bug in that code than most others, even though the particular bug does not
+interfere with the MontiumC frontend. In the end, I think I managed to find a
+decent balance, though it might have been tipped slighly in favour of the LLVM
+project.

 
 \subsection{Coding}
 This section says something about the challenges encountered while actually
 
 \subsection{Coding}
 This section says something about the challenges encountered while actually


@@ -98,6 +138,7 @@ writing code, if I can think of enough things to say here.
 This section says something about working with colleagues in various ways.
 
 \subsection{Staying generic}
 This section says something about working with colleagues in various ways.
 
 \subsection{Staying generic}

+\label{StayingGeneric}

 This section says something about the challenge of writing generic code:
 (changes to) transformations that are useful for both LLVM (ie on regular
 architectures) as well as for Recore (on the Montium).
 This section says something about the challenge of writing generic code:
 (changes to) transformations that are useful for both LLVM (ie on regular
 architectures) as well as for Recore (on the Montium).