COMPILER TECHNIQUES FOR MATLAB PROGRAMS ... - CiteSeerX

Built-in
R
R
W
Function
W
Multiple
R/W
Start
1
2
3
M-File
R
W
Variable
R/W
R/W
Empty
Figure 4.3: State diagram for dierentiation between functions and variables.
4.2 Static Single Assignment
4.2.1 Extensions to the Symbol Table for the SSA Representation
To support the SSA representation, our symbol table is divided in two main parts: the entry
list and for each entry, a list containing all variable instances. As an example, consider again
the SSA representation of the program to compute the average of a vector, presented in
Figure 3.3(b). The data structure for the symbol table corresponding to this program is
outlined in Figure 4.4.
Each nodeintheentry list contains the information that is shared by all instances
of the corresponding variable, such as loaded name and program name 1 ,aswell as global
information used by the symbol table manager, suchasthenumber of instances and a pointer
to the start of the corresponding variable's instance list. Information about built-ins and
M-les are also stored in the symbol table. Therefore a eld kind is used to indicate if the
entry is a variable, built-in, M-le, or multiple (for identier in the state Multiple described
1 The original MATLAB name must be saved for the load function. The loaded name may be dierent
than the program name due to renaming performed by the inliner.
35