parkerk / tigpiler

A simple Tiger to MIPS compiler, written in Standard-ML

Tigpiler

An SML based Tiger to MIPS compiler

Requirements

• SML/NJ 110.73

Setup

• Clone repo git clone [email protected]:ParkerK/Tigpiler.git
• Change to the program directory cd Tigpiler/RegisterAllocation

Testing

• Run the test program to compile and run the binary sml test.sml

Status / Updates

We believe that this compiler is fully functional (though a tad dumb at times). In regards to changes on past parts, we have changed quite a bit. On the Lexer, we went through and fixed all of the issues pointed out. In addition, we found one where it could not handle 'then'. It still won't handle illegal integers (e.g. var:=5a) but being that this was optional we simply encourage any users to try to make illegal integers.

For the Parser, the only thing wrong was the excluded documentation. You are reading the documentation at this very moment, which proves that we now have documentation.

For Frame Analysis and IR we had full credit, but we still went though and fixed a few issues with things like declarations.

We also fixed Instruction Selection to handle MOVES correctly, added a missing procEntryExit1 funtion, and changed the psuedo assembly to valid MIPS.

In regards to register allocation our compiler will correctly create a control flow graph, liveness analysis, and interference graphs. It will even color registers and will spill. It's not very bright (we still love it though) though and will give up as soon as it detects something wrong.

Upon running sml test.sml the script will spit out the assembly representation of all of the test programs that we have collected. You can run sml test.sml in any directory to see the output of that stage (e.g., running sml test.sml in the IRTranslation directory will save the IR represnetation in the output directory).

Parts

1.Lexer (9/19)

To Fix:

• A little too aggressive illegal escape char checker. e.g. \ is a regular backslash. Currently your lexer reporting error
• Currently you seem to be checking unclosed comments by the use of escape characters. There's a better implementation.
• Need to handle illegal integers, e.g. var a:=5a
• There is a bug in your lexer, such that strings ending with f are not being processed

2.Parser (10/17)

To Fix:

• Missing documentation

3.Semantic Analysis (10/31)

To Fix:

• If, while, ... expressions are returning errors when not supposed to, e.g. "if(5>3)..." returns integer required error.
• Certain expressions should not return any value at all (see page 516). For example a:=(if (5>4) then 3) should return an error
• For "if then else" expressions the types of "then" and "else" values must be the same
• Need to handle recursive declarations: At the moment not throwing errors. (See page 120)
• How are you handling cases where types have the same name as variables? Should it return an error?

4.Frame Analysis and Intermediate Representation (11/14)

To Fix:

• None

5.Instruction Selection (11/21)

To Fix:

• Incorrect instructions used, ie 'LOAD' instead of 'lw'

6.Register Allocation (12/5)

To Fix:

• Color nodes, everything is showing as $t0

7.Working compiler, produces assembly (12/9)

To Fix:

• Fix previous issues from past modules

tigpiler's Issues

tiger.lex <STRING>{quote} problem

The parenthesis does not close.

TypeChecker - Recursive Statements

Need to handle recursive declarations: At the moment not throwing
errors. (See page 120)

TypeChecker - Type Handling

How are you handling cases where types have the same name as
variables? Should it return an error?

TypeChecker - Returning Values

• Certain expressions should not return any value at all (see page
  516). For example a:=(if (5>4) then 3) should return an error

IR - Function calls

test case 27

TypeChecker - type not defined errors

It is throwing errors on situations that arrise due to uncorrected
errors from previous projects. For example, the case on the
typechecker project, where your typechecker is throwing incorrects
"type not defined errors" in cases like "if(10>5)"

recursive and mutually recursive functions

Afterwards, check also recursive and mutually recursive functions. It
seems there is also a labeling error. At the moment they are throwing
uncaught exception errors

For Loop Bug in Translate

"I have also found a bug in the for loop in your translate module
(part of IR/Frame project) that I didn't report to you earlier. The
for loop is jumping to an incorrect label such that the conditions are
not being tested."

TypeChecker - If/Then

• For "if then else" expressions the types of "then" and "else" values
  must be the same

TypeChecker - If/While

If, while, ... expressions are returning errors when not supposed to,
e.g. "if(5>3)..." returns integer required error.

Lexer - Start pos of String is wrong

The ending position of the string is used as the starting position.

The following is a simple tiger program

"string"

The output should be

STRING(string)     2
EOF   10

instead of

STRING(string)     9
EOF   10

tiger.lex <STRING> problem

does not handle "

Lexer Bug

Need to handle illegal integers, e.g. var a:=5a