Project README · Architecture · Backend guide · API documentation

Synopsis

bfc [options] <file.bf>

bfc accepts one Brainfuck source file and optional compiler flags.

Options

-h, --help

Print the available command-line options and exit successfully.

bfc --help

-S, --assembly

Generate assembly and stop.

bfc -S hello.bf

When -o is not provided, the current implementation appends .s to the complete input path:

hello.bf -> hello.bf.s

tests/a.bf -> tests/a.bf.s

Use -o to select a different assembly-file path:

bfc -S hello.bf -o hello.s

The current implementation only writes output when -S is present. The assemble-and-link stage for producing a final executable is not implemented yet.

-o, --output <file>

Set the output path.

bfc -S hello.bf -o build/hello.s

The value must be supplied as the next argument.

Supported:

bfc -o hello.s -S hello.bf

bfc --output hello.s -S hello.bf

Not currently supported:

bfc -ohello.s hello.bf

bfc --output=hello.s hello.bf

Specifying the output option more than once is an error.

-t, --target <triple>

Select the code-generation target.

bfc -S --target aarch64-apple-darwin hello.bf

When no target is provided, bfc selects the host architecture and operating system using compiler predefined macros.

The target value must be supplied as the next argument. The --target=<triple> form is not currently supported.

--fno-comments

Disable bfc's semicolon-comment extension.

By default, a semicolon begins a comment that continues to the end of the current line:

+++++ ; this text is ignored

.

With --fno-comments, the semicolon is treated like any other non-Brainfuck character and does not suppress later Brainfuck instructions on that line.

bfc -S --fno-comments source.bf

--

Stop parsing options.

This allows an input path beginning with -:

bfc -S -- -program.bf

Everything after -- is treated as a positional argument.

Target triples

The target parser currently recognizes:

Target triple	Architecture	Operating system
aarch64-apple-darwin	AArch64	macOS
x86_64-apple-darwin	x86-64	macOS
aarch64-unknown-linux-gnu	AArch64	Linux
x86_64-unknown-linux-gnu	x86-64	Linux
aarch64-pc-windows-msvc	AArch64	Windows
x86_64-pc-windows-msvc	x86-64	Windows
i386-pc-windows-msvc	i386	Windows

Recognizing a triple does not guarantee that a backend is implemented.

Currently implemented backend selections:

Target triple	Backend status
aarch64-apple-darwin	Implemented
x86_64-apple-darwin	Implemented
Linux targets	Recognized, backend not yet selected
Windows targets	Recognized, backend not yet selected

Requesting a recognized target without an available backend produces an error.

Examples

Emit assembly for the host target

bfc -S hello.bf

Output:

hello.bf.s

Emit assembly to a selected path

bfc -S hello.bf -o hello.s

Emit macOS AArch64 assembly

bfc -S \
    --target aarch64-apple-darwin \
    hello.bf \
    -o hello-aarch64.s

Emit macOS x86-64 assembly

bfc -S \
    --target x86_64-apple-darwin \
    hello.bf \
    -o hello-x86_64.s

Compile a source path beginning with -

bfc -S -- -example.bf

Argument rules

Exactly one input path is accepted.
The input path may appear before, between, or after options.
Options requiring values consume the following argument.
Repeating -o or --target is an error.
An unknown option is an error.
Omitting the input file is an error, except when help is requested.
-- disables option parsing for all remaining arguments.

Exit status

bfc returns:

EXIT_SUCCESS when compilation succeeds.
EXIT_SUCCESS after printing help.
EXIT_FAILURE when argument parsing, input loading, lexing, validation, IR construction, optimization, code generation, or output writing fails.

Current limitations

Combined short options are not supported.
Attached option values are not supported.
--option=value syntax is not supported.
Only one input file is accepted.
The final assembler/linker stage is not implemented.
Linux and Windows target triples are recognized but do not yet have selected backends.
The default assembly output keeps the original extension and appends .s.