CS322 Winter’09: Languages and Compiler Design I I 01/08/09
Prof. Jingke Li (FAB 120-06, [email protected]), Classes: TTh 2-3:50pm, URBAN 304, Office Hours: TTh 10-11am.
Project #1: IR Code Generation (I)
(Due Thursday 01/22/09 @ 5pm)
This project is to implement a first version of an IR code generator for the MINI compiler. The target
IR is the IR tree language discussed in class. The generator is to be implemented as a visitor to the MINI
AST nodes. The visitor interface is defined in TransVI.java in the ast subdirectory.
When the visitor IrgenVisitor1 is invoked on a MINI AST Program node, an IR tree rooted at a PROG
node should be generated. The following is a guide on how to translate specific AST nodes. Since this is a
first version of the IR code generator, some nodes’ translations are simplified.
Declarations
•VarDecls — If a VarDecl has no initialization expression, no action is needed; otherwise, it is treated
as an assignment statement, and is translated into a MOVE node. All variables retain their names in
this project.
•MethodDecls — Each MethodDecl node is translated into a FUNC node. To do this,
–translate the method’s VarDeclList into a (possibly empty) STMTlist, and
–translate the method’s StmtList into a STMTlist.
Merge the two STMTlists and create a FUNC node. (The list classes in our IR tree are defined as
extensions of Java’s Vector class, hence the method addAll could be used to merge two lists.)
The FUNC’s label field gets the Method’s name. Its two other fields, varCnt and argCnt, are not used
in this project, and hence should be set to 0s.
•ClassDecls — AClassDecl node consists of a list of VarDecls and a list of MethodDecls. VarDecls
are to be ignored here, since they will be handled in NewObject node. Each MethodDecl is translated
into a FUNC node, so a ClassDecl is translated into a FUNClist. The order of elements in a FUNClist
does not affect the program’s correctness.
The class id and its parent pointer are not used in this project.
•Program — The FUNClists from multiple ClassDecls are merged into a single FUNClist, and is used
to create a PROG node.
Statements
•Assign — Translate it into a MOVE node.
•CallStmt — Translate it straightforwardly into a CALLST node. (A Call node similarly translates into
aCALL node.)
•If and While — Translate each into a CJUMP node, together with other statements, as discussed in
class.
•Return — Translate it straightforwardly into a RETURN node.
•Print — Translate it into a CALLST node; the target of call is either prInt or prString.
