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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 26 |
1 files changed, 16 insertions, 10 deletions
@@ -3,9 +3,9 @@ Compilers nowadays are written in languages like C, which themselves need to be compiled. But then, you need a C compiler to compile your C compiler! Of course, the very first C compiler was not written in C (because how would it be -compiled?). Instead, it was slowly built up, starting from a very basic -assembler, eventually reacing a full-scale compiler. This process is known as -bootstrapping. In this repository, we'll explore how that's done. Each directory +compiled?). Instead, it was built up over time, starting from a very basic +assembler, eventually reaching a full-scale compiler. +In this repository, we'll explore how that's done. Each directory represents a new "stage" in the process. The first one, `00`, is a hand-written executable, and the last one will be a C compiler. Each directory has its own README explaining what's going on. @@ -13,15 +13,21 @@ README explaining what's going on. You can run `bootstrap.sh` to run through and test every stage. To get HTML versions of all README pages, run `make`. -## the basics +Note that the executables produced in this series will only run on +64-bit Linux, because each OS/architecture combination would need its own separate +executable. + +The README for the first stage is [here](00/README.md). + +## prerequisite knowledge In this series, I want to explain *everything* that's going on. I'm going to need to assume some passing knowledge, so here's a quick overview of what you'll -want to know before starting. I can't explain everything so you may need to do -your own research. You don't need to understand each of these in full, just get -a general idea at least: +want to know before starting. +You don't need to understand everything about each of these, just get +a general idea: -- what an operating system is +- what a system call is - what memory is - what a programming language is - what a compiler is @@ -35,7 +41,7 @@ decimal. - bits, bytes, kilobytes, etc. - bitwise operations (not, or, and, xor, left shift, right shift) - 2's complement -- null-terminated strings +- ASCII, null-terminated strings - how pointers work - how floating-point numbers work - maybe some basic Intel-style x86-64 assembly (you can probably pick it up on @@ -73,7 +79,7 @@ with itself, we'll get the same executable either way. In 1984, Ken Thompson wrote the well-known article [Reflections on Trusting Trust](http://users.ece.cmu.edu/~ganger/712.fall02/papers/p761-thompson.pdf). -This is one of the things that inspired me to start this project. To summarize +This is one of the inspirations for this project. To summarize the article: it is possible to create a malicious C compiler which will replicate its own malicious functionalities (e.g. detecting password-checking routines to make them also accept another password the attacker knows) when used |