hjc

The Haskell MiniJava Compiler build at the LMU course "Compiler Construction"

How to use

> git clone https://github.com/cirquit/hjc
> cd hjc
> stack build && stack install
> hjc --help
hjc - A MiniJava Compiler in Haskell

Usage: hjc javaFile [--showAst] [-t|--showTime] [--canonCmm] [-c|--compileToCmm]
           [-w|--compileToX86] [-g|--createIFGraph] [--javaOutputDir javaDir]
           [--cmmOutputDir cmmDir] [--x86OutputDir x86Dir]
           [--cfOutputDir graphDir]
           [-e|--typeErrLvl [AllErrors|Silently|FirstError]]
           [-x|--compileToAllocatedX86] [--showJava] [-s|--inSequence]

Available options:
  --showAst                show Ast
  -t,--showTime            show Time
  --canonCmm               canonize Cmm
  -c,--compileToCmm        compile to Cmm
  -w,--compileToX86        compile to X86 Code
  -g,--createIFGraph       create Control Flow Graph
  --javaOutputDir javaDir  directory of java files
  --cmmOutputDir cmmDir    directory of cmm files
  --x86OutputDir x86Dir    directory of x86 assembly files
  --cfOutputDir graphDir   directory of control flow graph
  -e,--typeErrLvl [AllErrors|Silently|FirstError]
                           defines which level of errors should bee shown
  -x,--compileToAllocatedX86
                           compile to allocated X86 Code
  --showJava               show the recreated java output
  -s,--inSequence          run the computation sequential
  -h,--help                Show this help text

Features

definition + declaration is allowed

int x = 1;

if and else may be in a single line without braces

if (boolean_value) do_something();
else do_something_else();

parens in expressions allowed

(1 + 2) * 3  // returns 6

the register allocation is in parallel, by sharing the fresh variables in a an IORef. This is on by default and can be removed by the flag -n
we support multiple level instruction removal by not used nodes in the graph and mov's to unused temps
we initialize every variable with 0 by default, so code like this is allowed

int x = 2;
int y;
int z = y + x; // 2

we created a simple DSL for working with the x86 assembly code, which supports comments for intermediate representation

...
     DIV_C   -> do 
         mov eax op1  # "moving first arg to eax for idiv"
         t <- nextTempO 
         mov t op2
         cdq
         idiv t
         mov op1 eax  # "move idiv result to initial destination"
...

we have a nice command line interface, which is extendable and can configure almost every switch in this compiler
we've written our own parser with megaparsec and could therefore create nice error messages (unfortunately, colors are not visible here)

> hjc examples/Arg.java
>> Starting to lex examples/Arg.java
>> examples/Arg.java:8:18: error:

  unexpected tokens: [Tokens ('{' :| "")]
    expected tokens: [Tokens ('(' :| ""),Tokens ('_' :| ""),Label ('a' :| "lphanumeric character")]

...
       public int go{int i} {
...
                   ^^^
  failed parsing.
>> Finished in: 120.0ms
--------------------------------------------------------------------------------

the same goes for the typechecking (with different error levels, configurable via flags)

> hjc examples/Arg.java
>> Starting to lex examples/Arg.java
>> Typechecking failed: 

        Terminating with 3 typeerrors.

   #1 class A : method go:
        identifier "j" is undefined and thus has no type

   #2 class A : method go:
        type  "Object" does not match expected types "int" in expression:

         j

   #3 class A : method go:
        operator  /  is not defined for type "Object", allowed types are "int"

we also have a full testsuite on every automatically testable property of the steps in between

How to compile to binary and run

Compile with hjc <filename>.java. This will create a x86output folder for you, then you have to link it yourself. In this project structure, the folder already has a Makefile which can be used by make file=<filename>-allocated.s.

How to use the C-- Backend

Compile to name.tree with a configurable flag -c and --canonCmm. Install the tree2c tool:

> git clone https://gitlab.cip.ifi.lmu.de/schoepp/Compilerbau17
> cd src/tree2c
> stack build
> stack install

Check if you have libc6-dev-i386 or g++-multilib or libc6-dev-i386 package installed. In my case, this only worked with clang-3.8.

> cd cmm-output
> tree2c <name>-cmm.tree > <name>.c
> gcc -m32 <name>.c runtime.c -o <name>
> ./name

Otherwise, in the cmm-output folder, there is a prepared Makefile, which can be run by make file=Add-canonized.tree.

Graph visualization

Install the graphviz program - sudo apt-get install graphviz. Set the config flag --createIFGraph. To show the graph as PostScript file:

> cd if-graph-output
> dot -Tps ProgramName.dot -o output.ps

Otherwise, in the if-graph-out folder, there is a prepared Makefile, which can be run by make file=Arg.dot.

Development

This project is using stack-1.3.2.

Styleguide

Using hindent-5.2.1. Install with stack install --resolver nightly-2016-10-17 hindent.

Testing

Run tests (in the main folder of the repository)

stack test

Run a specific test file i.e.

stack test --test-arguments "-m "TypeCheck/TypeCheck""

Fail fast

stack test --test-arguments "--fail-fast"

Run a specific test file, fail fast and filewatch

stack test --file-watch --test-arguments "-m "TypeCheck/TypeCheck" --fail-fast"

Errors
- 111: IndexOutOfBounds
Debug with gdb

> gdb ./testprog

>>> tui enable  -- enables a terminal ui
>>> refresh     -- redraws the tui

>>> b Lmain     -- set breakpoint at function Lmain
>>> n           -- next
>>> print var   -- shows var
>>> backtrace   -- shows stacktrace
>>> quit

cirquit / hjc

hjc