An Overview of the SUIF2 System
Monica Lam
Stanford University
http://suif.stanford.edu/
The SUIF System
PGI Fortran
Interprocedural Analysis
Parallelization
Locality Opt
C
EDG C++
SUIF2
Alpha
Java
Inst. Scheduling
Register Allocation
x86
Research Infrastructure: Support at 3 Levels
 I. Compose compiler with existing passes
 Front ends + passes
 Easy expression of compiler compositions (dynamically)
 II. Develop new passes
 User concentrates on algorithmic issues
 Infrastructure takes care of common functionalities
 Standard intermediate representation and associate tools
 Common utilities and data structures
 III. Develop new IR (new language constructs or analyses)
 Easy definition of IR nodes
 Old code works with new IR without recompilation
I: Compose Compiler with Existing Passes
 Previous system
 Each pass is an independent program that reads/writes SUIF in a file
 Advantages: modular, visibility of intermediate results
 Disadvantages: expensive disk access
 New system
 write code once, can run on program on disk or in memory
 simple development, efficient deployment
 How?
A pass = a common driver + module
A compound pass
• a common driver + series of modules loaded dynamically
Modular Compiler System
COMPILER
A series of stand-alone programs
Suif-file1
driver+module1
Suif-file2
driver+module2
Suif-file3
A driver that imports & applies
modules to program in memory
Suif-file1
Suifdriver
imports/executes
module1
module2
module3
driver+module3
Suif-file4
Suif-file4
SUIF Driver
> suifdriver
suif> import basicnodes suifnodes
suif> import mylibrary
suif> load test.suif
suif> mylibrary_pass1
suif> print test.out
suif> save test.tsuif
 Suifdriver:
 accepts a simple scripting language
 pre-registered modules (import, load, print, save)
 loads libraries dynamically which can register new modules (new
commands)
The SUIF Architecture
Executable
suifdriver
MODULES:
Passes
analyses
optimizations
Kernel
suifkernel
iokernel
IR
suifnodes
basicnodes
Components
 Kernel: provides all basic functionality
 iokernel: implements I/O
 suifkernel: hides iokernel and provides modules support, cloning,
command line parsing, list of factories, etc.
 Modules
 passes: provides a pass framework
 IR: basic program representations
 Suifdriver
 provides execution control over modules and passes using a scripting
language
II. Develop a New Pass
 Kernel: provides all basic functionality
 iokernel: implements I/O
 suifkernel: hides iokernel and provides modules support, cloning,
command line parsing, list of factories, etc.
 Modules
 passes: provides a pass framework <-- Derive from this framework
 IR: basic program representations
 Suifdriver
 provides execution control over modules and passes using a scripting
language
Compilation System = SuifEnv + Modules
 SuifEnv:
 Keeps the states of the compilation
 Holds onto the representation (FileSetBlock) and the loaded modules
 A module is a C++ class
 that implements either a pass or a set of nodes in IR
 must have a unique module_name
 no global variables
 one or more modules make up a dll
 each library includes a function (init_<dllname>) to register all
modules dynamically
 Registration is based on a prototype object
Example Pass: Count Statements in Procedures
class mypass: public Pass {
public:
mypass(SuifEnv *env, const Lstring &name): Pass(env, name) {}
virtual ~mypass() {}
Module *clone() const {return(Module*) this:}
void do_procedure_definition (ProcedureDefinition* proc_def)
{
cout << proc_def->get_procedure_symbol() ->get_name()
cout << object_iterator<ExecutionObject>(proc_def).length();
}
}
extern “C” void init_mypass (SuifEnv *suif_env) {
suif_env->get_module_subsystem()->register_module
(new mypass (suif_env, “mypass”));
}
Tools for writing passes
 Traversing and manipulating data structures
 Visitors: dispatch method according to type
 Iterators: simple iteration of certain objects
 Walkers: user-controllable traversal of data structures
 Data structures
 Infinite precision integers
 strings
 lists, sets, hash maps
 assertion/error handling
Program Representation
 Multiple representations for semantics at different abstraction levels
 e.g. FOR loops or statement list with branches and jumps
High-level representation useful for high-level transformations
 => Superset representation:
mixture of high-level and low-level constructs
Dismantlers lower representation
 Allow analysis to operate at different levels of abstraction
 e.g. analysis may/may not care about specific arithmetic operators
 => Uses object-oriented class hierarchy
SUIF IR Design
 Root: Object
 Uniform functionality
 Fields accessed with get_<field>,
and set_<field>
 printing
 I/O to disk
 cloning
 iterators
 walkers
 Memory management aid:
 object creation via factories
 owner edges embed a tree into
program representation
Object
SUIFObject
AnnotableObject
SymbolTable
ScopedObject
ExecutionObject
Statement Expression
Supports Code with Abstraction
ExecutionObject
Statement
get_child_statements
IfStatement
WhileStatement
get_then_part
get_else_part
get_body
 Maximize reuse by abstract fields
 allow uniform access to different child components
III. Extending the IR
 Goals
 Support extension by different research groups
Code written for a high-level IR should work on refined IR
(without recompilation!)
 Easy specification of new extensions
Grammar-based specification
 How?
 Meta-class system
Objects contain information describing representation
If environment does not include definitions of refinements
• information retained even if methods are not available
• written out when representation saved
Insulating the User from the Implementation
Object Definition (.hoof)
SUIF Macro Generator
a general grammar-based tool
Interface for user (.h)
Implementation in
Meta-Class System (.cpp)
Meta-Class System
reading & writing to file in
machine-independent format
• Easy for the programmer
• Easy for the implementor to develop the system
Example of a Hoof Definition
concrete New
{ int x; }
class New : public SuifObject
{
public:
int get_x();
void set_x(int the_value);
~example();
void print(…);
static const Lstring &get_class_name();
…
}
 Uniform data access functions (get_ & set_)
 Automatic generation of meta class information etc.
Examples of Suif Nodes
abstract Statement : ExecutionObject
{
virtual list<Statement* owner> child_statements;
...
}
concrete IfStatement : Statement
{
Expression * condition in source_ops;
Statement * owner then_part in child_statements;
Statement * owner else_part in child_statements;
}
Documentation





The SUIF2 Infrastructure Guide (an index to all documentation)
Overview of the SUIF Infrastructure
The SUIF Representation Guide
The Basic SUIF Programmer’s Guide
Web page: http://suif.stanford.edu/suif2