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Diffstat (limited to '05/README.md')
| -rw-r--r-- | 05/README.md | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/05/README.md b/05/README.md index 2347661..0244a4b 100644 --- a/05/README.md +++ b/05/README.md @@ -389,7 +389,7 @@ The last line causes the `inline` keyword (added in C99) to be ignored. Fewer changes would've been needed for an older version of TCC, but older versions didn't support x86-64 assembly, which might end up being relevant... -## \*the nightmare begins +## \*libc If you look in TCC's source code, you will not find implementations of any of the C standard library functions. So how can programs compiled with TCC use those functions? @@ -401,14 +401,15 @@ if there a security bug were found in `printf`, it would be much easier to repla every program which uses `printf`. Now this library file is itself compiled from C source files (typically glibc). -So, we can't really say that the self-compiled TCC was built from scratch. And there could be malicious -self-replicating code in glibc! - -So, why not just compile glibc with TCC? -Well, it's not actually possible. glibc can pretty much only be compiled with GCC. -This stage's C compiler definitely can't compile GCC, so we'll need a libc implementation to -compile GCC. Hmm... - -Other libc implementations don't seem to like TCC either, so it seems that the only option left is to -make a new libc implementation, use that to compile GCC (probably an old version of it which TCC can compile), -then use GCC to compile glibc. It will definitely be a large undertaking... +So, we can't really say that the self-compiled TCC was built from scratch, and there could be malicious +self-replicating code in glibc. + +You can't compile glibc with TCC, but +it's possible to build an old version of `musl`, an alternate libc +(you can run `CC=../tcc-0.9.27/tcc0 make` in the `musl-0.6.0` directory here). + +You should be able to use musl alongside TCC to build an old version of GCC (git revision +`79a6d9b7ff3822675ee44d8d6cad86027dadd664` seems workable). This also requires +building several tools needed to compile GCC. You should then be able to build (possibly an old version of) +glibc, and with that, a modern version of GCC. +This is all extremely tedious, though, so I'm not planning on doing it anytime soon. |