differentprogramming/my-pascal-compiler

A simple compiler for My Pascal, with LLVM as its backend. - in order to learn llvm

My Pascal Compiler

My Pascal is a simpler and slightly modified version of the ISO7185 Pascal programming language. My Pascal Compiler is the compiler for My Pascal, with LLVM as its backend.

Feature

• Supports most of the data types in Pascal, including multi-dimension arrays, strings and record types.
• Supports most of the operations and statements in Pascal.
• Supports most of the built-in functions and procedures of Pascal, including read, write, fillchar, etc.
• Can compile My Pascal source code to LLVM IR code, assembly, object file or executable file.

Usage

mpc [-d] [-t filetype] [-o outfile] infile

-d
    Prints debug message.

-t filetype
    Specify what kind of output mpc should generate. `filetype` can be
        ll: llvm IR code
        asm: textual assembly
        obj: native object file

-o outfile
    Rename output file of mpc to `outfile`

Example

Source file (example.pas):

var
    a, b: integer;    
begin
    read(a, b);
    writeln(a + b);
end.

Use mpc -d example.pas to print the following debug message (AST) and compile source code to executable file.

program(
    variable_declaration(
        id_sequence_with_type(
            id(a)
            id(b)
            --- type ---
            int_type()
        )
    )
    function_call(
        id(read)
        --- param ---
        id(a)
        id(b)
    )
    function_call(
        id(writeln)
        --- param ---
        add(
            id(a)
            id(b)
        )
    )
)

Use mpc -t ll example.pas to compile source code to LLVM IR code.

; ModuleID = 'my_pascal_module'
source_filename = "my_pascal_module"

@a = internal global i32 zeroinitializer
@b = internal global i32 zeroinitializer
@scanf_format = private unnamed_addr constant [5 x i8] c"%d%d\00"
@printf_format = private unnamed_addr constant [4 x i8] c"%d\0A\00"

define i32 @main() {
entry:
  %a = load i32, i32* @a
  %b = load i32, i32* @b
  %call_scanf = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @scanf_format, i32 0, i32 0), i32* @a, i32* @b)
  %a1 = load i32, i32* @a
  %b2 = load i32, i32* @b
  %add_tmp = add i32 %a1, %b2
  %call_printf = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @printf_format, i32 0, i32 0), i32 %add_tmp)
  ret i32 0
}

declare i32 @scanf(i8*, ...)

declare i32 @printf(i8*, ...)

Check test/example directory for more examples.

Build from Source

Now both in-source and out-of-source compilation is allowed.

Dependencies

• gcc >= 5.4
• cmake >= 3.10
• llvm >= 6.0

Build My Pascal Compiler

cmake --build <build-dir> --target mpc

Run Tests

• Run all tests

  cmake --build <build-dir> --target mpc-test
  

• Run normal tests

  cmake --build <build-dir> --target mpc-test-normal
  

• Run validation tests

  cmake --build <build-dir> --target mpc-test-validation
  

• Run examples

  cmake --build <build-dir> --target mpc-test-example
  

Attention for MacOS Users

1. Use homebrew to install llvm.

brew install llvm

2. Follow hints in brew info llvm, implement

echo 'export PATH="/usr/local/opt/llvm/bin:$PATH"' >> ~/.bash_profile

3. Use homebrew to install coreutils

brew install coreutils

Building Steps are totally same as above.

Documentation

WIP

Difference with Pascal

See documentation (WIP)