From 2a4088119cf41175457414dfa59bd4064b8f0562 Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Wed, 1 Jan 2020 17:04:37 -0800 Subject: 5852 --- archive/3.transect/compiler8 | 53 -------------------------------------------- 1 file changed, 53 deletions(-) delete mode 100644 archive/3.transect/compiler8 (limited to 'archive/3.transect/compiler8') diff --git a/archive/3.transect/compiler8 b/archive/3.transect/compiler8 deleted file mode 100644 index b3b35271..00000000 --- a/archive/3.transect/compiler8 +++ /dev/null @@ -1,53 +0,0 @@ -== Goal - -A memory-safe language with a simple translator to x86 that can be feasibly written in x86. - -== Definitions of terms - -Memory-safe: it should be impossible to: - a) create a pointer out of arbitrary data, or - b) to access heap memory after it's been freed. - -Simple: do all the work in a 2-pass translator: - Pass 1: check each instruction's types in isolation. - Pass 2: emit code for each instruction in isolation. - -== types - -int -char -(address _) -(array _ n) -(ref _) - -== implications - -addresses can't be saved to stack or global, - or included in compound types - or used across a call (to eliminate possibility of free) - - : (address T) <- advance : (array T), : (index T) - -arrays require a size -(ref array _) may not include a size - -argv has type (array (ref array char)) - -variables on stack, heap and global are references. The name points at the -address. Use '*' to get at the value. - -instructions performing lookups write to register, so that we can reuse the register for temporaries -instructions performing lookups can't read from the register they write to. - But most instructions read from the register they write to?! (in-out params) - -== open questions - -If bounds checks can take multiple instructions, why not perform array -indexing in a single statement in the language? - -But we want addresses as intermediate points to combine instructions with. - -Maybe disallow addresses to function calls, but allow addresses to non-heap -structures to be used spanning function calls and labels. - -That's just for ergonomics. Doesn't add new capability. -- cgit 1.4.1-2-gfad0