c-bootstrap

• Bootstrapping a simple C/C++ based compiler written in C++.
• The compiler will intially be used to build simple C programs, and then extend the grammar enough so that it is able to compile itself.

Requirements

• cmake
• For Binary CodeGen:
  • nasm
  • macOS with Intel x64 CPU

Usage

Building

Building/Running/Testing in a unix environment:

Build Code

git clone https://github.com/rdtscp/c-bootstrap.git
cd ./c-bootstrap/
mkdir build ; cd build
cmake -DCMAKE_BUILD_TYPE=Debug ../
make -j && ctest --output-on-failure

Dot Graph Output

Building/Running/Testing in a unix environment:

# Run Examples below
./acc ../test/tests/Test_Parser/BinOp/test.cpp test.dot --graph
./acc ../test/tests/Test_Parser/BinOp/test.cpp test_opt.dot --graph --opt

Then paste the contents of test.dot and test_opt.dot into a dot-graph generator (I recommend http://www.webgraphviz.com/). You can then see a graphical representation of the input program.

Binary Generation

Building/Running/Testing on macOS:

# Run Examples below
./acc ../test/tests/main.cpp test.out
./test.out

---

Pre-Processor Grammar

#define
#else
#endif
#ifdef
#ifndef
#include

Mini-C/C++ Grammar

Progressively changing to adopt new features of the language(s).

program      -> (include)* (decl)* EOF

decl         -> classdecl ";"
             -> vardecl ";"
             -> arrvardecl ";"
             -> fundecl ";"
             -> fundef
             -> typedecl ";"
             -> enumdecl ";"

classdecl    -> "class" IDENT "{" (decl | accessmod )* "}" ";"

accessmod    -> "public:" | "private:" | "protected:"

vardecl      -> type IDENT

arrvardecl   -> vardecl "[" INT_LITERAL "]"

fundecl      -> type (IDENT | opoverloads) "(" params ")"

opoverloads  -> "operator="
              | "operator=="
              | "operator!="

fundef       -> type IDENT "(" params ")" block

typedecl     -> "typedef" type IDENT

enumdecl     -> "enum" "{" statelist "}"

statelist    -> (IDENT ["=" INT_LITERAL] ",")* IDENT ["=" INT_LITERAL]

type         -> ("int" | "char" | "void", "unsigned int", "bool" | classtype ) (ASTERIX)*

classtype    -> IDENT

params       -> [ type IDENT ("," type IDENT)* ]

stmt         -> vardecl ";"
              | block
              | "do" stmt "while" "(" exp ")" ";"
              | "while" "(" exp ")" stmt
              | "if" "(" exp ")" stmt ["else" stmt]
              | "return" [exp] ";"
              | "delete" IDENT ";"
              | "delete[]" IDENT ";"
              | "throw" STRING_LITERAL ";"
              | expr "=" expr ";"
              | expr ";"

block        -> "{" stmt* "}"

expr         -> boolExpr ( "?" boolExpr ":" boolExpr )*
              | boolExpr "+=" boolExpr

boolExpr     -> equalExpr
              | equalExpr "||" equalExpr ( ( "||" || "&&" ) equalExpr )*
              | equalExpr "&&" equalExpr ( ( "||" || "&&" ) equalExpr )*

equalExpr    -> compExpr
              | compExpr "!=" compExpr
              | compExpr "==" compExpr

compExpr     -> addExpr
              | addExpr "<" addExpr
              | addExpr ">" addExpr
              | addExpr "<=" addExpr
              | addExpr ">=" addExpr

addExpr      -> mulExpr
              | mulExpr "+" mulExpr ( ( "+" || "-" ) mulExpr )*
              | mulExpr "-" mulExpr ( ( "+" || "-" ) mulExpr )*

mulExpr      -> unaryExpr
              | unaryExpr "*" unaryExpr ( ( "*" || "/" || "%" ) unaryExpr )*
              | unaryExpr "/" unaryExpr ( ( "_" || "/" || "%" ) unaryExpr )*
              | unaryExpr "%" unaryExpr ( ( "_" || "/" || "%" ) unaryExpr )*


unaryExpr    -> "sizeof" "(" type ")"
              | "*" objExpr
              | "(" type ")"
              | "-" objExpr
              | "++" objExpr
              | "new" type [ "(" litExpr ("," litExpr)* ")" ] ";"
              | "&" objExpr
              | "!" objExpr
              | objExpr "[" expr "]
              | objExpr

objExpr      -> funCall (objExprOp)*
              | IDENT (objExprOp)*
              | "this" (objExprOp)*
              | litExpr
            
objExprOp    -> "." funCall
              | "->" funCall
              | "." objExpr
              | "->" objExpr
              | "[" objExpr "]" 


funCall      -> IDENT "(" litExpr ("," litExpr)\* ")"
              | IDENT "(" litExpr ")"
              | IDENT "(" ")"


litExpr      -> INT_LITERAL
              | CHAR_LITERAL
              | STRING_LITERAL
              | "true"
              | "false"
              | "(" expr ")"
              | expr

---

macOS Notes

# Building Assembly:
acc main.cpp
# Building Objects
nasm -f macho64 x86.s
# Link Objects
ld -no_pie -macosx_version_min 10.15 -lSystem -o x86 x86.o