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cproc is a C11 compiler. It uses the QBE backend.

It implements most of the c language and is capable of building software including itself, gcc 4.7, binutils, and more.

One of the goals of cproc is to compile the entire oasis linux system (excluding kernel and libc).

Many packages have patches to fix various ISO C conformance issues, enabling them to be built.

See the oasis #13 for the current status of this effort, and the patch directories in the oasis package tree for any patches used.

Requirements

The compiler itself is written in C99.

At runtime, you need QBE, an assembler, and a linker for the target system. The preprocessor is not yet implemented; an external one is required.

Targets

  • x86_64-linux-musl

Building

Run ./configure to create a config.h and config.mk appropriate for your system. If your system is not supported by the configure script, you can create these files manually. config.h should define several string arrays (static char *[]):

  • startfiles: Objects to pass to the linker at the beginning of the link command.
  • endfiles: Objects to pass to the linker at the end of the link command (including libc).
  • preprocesscmd: The preprocessor command, and any necessary flags for the target system.
  • codegencmd: The QBE command, and possibly explicit target flags.
  • assemblecmd: The assembler command.
  • linkcmd: The linker command.

You may also want to customize your environment or config.mk with the appropriate CC, CFLAGS and LDFLAGS.

Once this is done, you can build with make.

Bootstrap

The Makefile includes several other targets that can be used for bootstrapping. These targets require the ability to run the tools specified in config.h.

  • stage2: Build the compiler with the initial (stage1) output.
  • stage3: Build the compiler with the stage2 output.
  • bootstrap: Build the stage2 and stage3 compilers, and verify that they are byte-wise identical.

What's missing

  • Digraph sequences (6.4.6p3, will not be implemented).
  • Variable-length arrays (#1).
  • volatile-qualified types (#7).
  • long double type (#3).
  • Inline assembly (#5).
  • Preprocessor (#6).
  • Generation of position independent code (i.e. shared libraries, modules, PIEs).

Implemented C23 features

N2265: _Static_assert without message

N2418: UTF-8 character constants

N2508: Free positioning of labels inside compound statements

N2510: Allow unnamed parameters in a function definition

N2549: Binary integer constants

N2900: Consistent, warningless, and intuitive initialization with {}

N2927: Not-so-magic typeof for C

N2975: Relax requirements for variadic parameter lists

N3029: Improved Normal Enumerations

N3030: Enhancements to Enumerations

Implemented GNU extensions

__asm__ labels

A declarator can be followed by __asm__("somelabel") to specify the assembler name of the object or function. This name is taken literally, so the resulting symbol will not be mangled according to the target's usual rules.

Built-in functions and types

  • __builtin_alloca: Allocate memory on the stack.
  • __builtin_constant_p: Test whether the argument is a constant expression.
  • __builtin_inff: float positive infinity value.
  • __builtin_nanf: float quiet NaN value.
  • __builtin_offsetof: Return the offset of a member in a struct or union.
  • __builtin_types_compatible_p: Test whether the two types are compatible.
  • __builtin_va_arg: Built-in suitable for implementing the va_arg macro.
  • __builtin_va_copy: Built-in suitible for implementing the va_copy macro.
  • __builtin_va_end: Built-in suitible for implementing the va_end macro.
  • __builtin_va_list: Built-in suitable for implementing the va_list type.
  • __builtin_va_start: Built-in suitable for implementing the va_start macro.