Cfront was the original compiler for C++ (then known as "C with Classes") from around 1983, which converted C++ to C; developed by Bjarne Stroustrup at AT&T Bell Labs.
Cfront defined the language until circa 1990, and many of the more obscure corner cases in C++ were related to its C++-to-C translation approach.
C++ (and Cfront) was directly responsible for many improvements in Unix linkers and object file formats, as it was the first widely used language which required link-time type checking, weak symbols, and other similar features.
[2][3] cppfront is different in scope in that it doesn't perform many validity checks on the code, instead relying on the C++ compiler for any checks that would require non-local understanding of the code such as establishing correct use of symbols.
Cfront on the other hand was a complete compiler that just happened to target the C language instead of an assembler.