# widcc

**Repository Path**: wln32/widcc

## Basic Information

- **Project Name**: widcc
- **Description**: No description available
- **Primary Language**: C
- **License**: MIT
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2024-09-12
- **Last Updated**: 2024-09-12

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

`widcc` is a stable branch of [`slimcc`](https://github.com/fuhsnn/slimcc) that
 - does not attempt to optimize codegen 
 - does not introduce new features (unless I really want certain projects to build)
 - would rather remove a feature than to support it incorrectly (not a motto but to avoid giving autoconf the wrong idea)
 
`slimcc` has accomplished a fairly good collection of real world projects it can build and 100% pass tests. `widcc` in turn is to maintain that status while being simpler-to-port and easier-to-modify.

The following C11 features are removed: `_Alignof` `_Atomic` `_Generic`. These are not seen commonly in use, therefore widcc still declare itself a C11 compiler. 

wid stands for "When in doubt" from the famous quote.

`widcc` is based on [Rui Ueyama's `chibicc`](https://github.com/rui314/chibicc), if you are familiar with chibicc and would like to know what's different here, refer [below](#changes-over-chibicc).

# Building & Running
 - Should just work on recent glibc-based (2.28+) x86-64 Linux.
 - Test script needs `bash`; depending on the distro, `file` and/or `glibc-static` packages may be required.
```
git clone --depth 1 https://github.com/fuhsnn/widcc
cd widcc
make test-stage2 -j
```
Run it in base directory like `CC=~/widcc/widcc`

# Building real-world projects

(package dependencies are assumed to be present)

`curl 8.9.1`
```
git clone --depth 1 https://github.com/curl/curl --branch curl-8_9_1
mkdir curl/cmakebuild
cd curl/cmakebuild
cmake ../ -DCMAKE_C_COMPILER=/full/path/to/widcc -DCMAKE_C_FLAGS=-fPIC
make -j
make quiet-test -j
```
`gcc 4.7.4`
```
mkdir gccbuild gccinstall
wget https://ftp.gnu.org/gnu/gcc/gcc-4.7.4/gcc-4.7.4.tar.bz2
tar -xf gcc-4.7.4.tar.bz2
cd gcc-4.7.4
find . -name 'configure' -exec sh ~/widcc/add_wl_pic.sh {} \;
sed -i 's/^\s*struct ucontext/ucontext_t/g' ./libgcc/config/i386/linux-unwind.h
cd ../gccbuild
CC=~/widcc/widcc MAKEINFO=missing ../gcc-4.7.4/configure --prefix=$HOME/gccinstall/ --enable-languages=c,c++ --disable-multilib --disable-bootstrap
make -j
make install
```
`git 2.46.0`
```
git clone --depth 1 https://github.com/git/git --branch v2.46.0
cd git
make CC=~/widcc/widcc V=1 test -j
```
`Perl 5.41.2`
```
git clone --depth 1 https://github.com/perl/perl5 --branch v5.41.2
cd perl5
sed -i -e 's/1.38/1.39/g' ext/Errno/Errno_pm.PL
sed -i "187i push(@file, '/usr/include/asm-generic/errno-base.h');" ext/Errno/Errno_pm.PL
sed -i "188i push(@file, '/usr/include/asm-generic/errno.h');" ext/Errno/Errno_pm.PL
./Configure -des -Dcc=$HOME/widcc/widcc -Dusedevel -Accflags=-fPIC
make test -j
```
`PHP 8.1.29`
```
git clone --depth 1 https://github.com/php/php-src/ --branch php-8.1.29
cd php-src
sh ~/widcc/add_wl_pic.sh ./configure
CC=~/widcc/widcc CFLAGS=-std=c99 ./configure --without-pcre-jit --disable-opcache --without-valgrind
make NO_INTERACTION=1 test -j
```
`PostgreSQL 17.0`
```
git clone --depth 1 https://github.com/postgres/postgres --branch REL_17_BETA3
cd postgres
sed -i 's/^\#if (defined(__x86_64__) || defined(_M_AMD64))/#if 0/g' src/include/port/simd.h
CC=~/widcc/widcc ./configure --disable-spinlocks --disable-atomics
make check -j
```
`Python 3.12.5`
```
git clone --depth 1 https://github.com/python/cpython --branch v3.12.5
cd cpython
CC=~/widcc/widcc ./configure
make test -j
```
`sqlite 3.46.1`
```
git clone --depth 1 https://github.com/sqlite/sqlite/ --branch version-3.46.1
cd sqlite
sh ~/widcc/add_wl_pic.sh ./configure
CC=~/widcc/widcc CFLAGS=-D_GNU_SOURCE ./configure
make testrunner
```
`TinyCC mob branch`
```
git clone --depth 1 https://repo.or.cz/tinycc.git
cd tinycc
CC=~/widcc/widcc ./configure
make -j
cd tests/tests2/
make
```
`toybox 0.8.11`
```
git clone --depth 1 https://github.com/landley/toybox --branch 0.8.11
cd toybox
sed -i 's/^\#define printf_format$/#define QUIET\n#define printf_format/g' lib/portability.h
make CC=~/widcc/widcc defconfig
make CC=~/widcc/widcc V=1
make CC=~/widcc/widcc tests
```
`vim trunk`
```
git clone --depth 1 https://github.com/vim/vim
cd vim
CC=~/widcc/widcc ./configure
make -j
make testtiny
```

# Changes over chibicc
- A stack manager for temporaries is introduced to avoid clobbering when setjmp/longjmp happen between pairs of push-pop, by translating push-pop's into mov's. `slimcc` took this further and added register allocation on top of the manager.
- Local variables of parallel scopes are folded into the same stack space, this dramatically eliminated segfaults in projects that do recursive calls a lot, and is about the only optimization worth mentioning in `widcc`.
- `chibicc`'s preprocessor hideset algorithm had issues with some obscure macro expansion tricks, I moved to a simple-but-dirtier design that avoid building hidesets altogether, but apparently [n0tknowing's chibicc fork](https://github.com/n0tknowing/chibicc) worked that out.
- `chibicc` had a tricky implementation of function call procedure, by interleaving argument-pushing with evaluation, then popping only the pass-by-reg ones off. I simplified the process by storing evaluated arguments to temporary variables, then copy into the right spots; it's inefficient, but the reduction in conceptual load worth it.
- The evaluation order of binary arithmetic operators are enforced left-right. Although it's implementation-defined behavior in C, I decided to reduce future surprises after encountering a test failing since git 2.43 because certain message output expressions are made on both sides of `|` and the validation script expect left-right behavior.