This commit makes the return type of most basic memory access primitives
Result, where the Err(()) case means a page fault happened, the
instruction should be aborted and execution should continue at the page
fault handler.
The following primites have a Result return type: safe_{read,write}*,
translate_address_*, read_imm*, writable_or_pagefault, get_phys_eip,
modrm_resolve, push*, pop*.
Any instruction needs to handle the page fault cases and abort
execution appropriately. The return_on_pagefault! macro has been
provided to get the same behaviour as the previously used JS exceptions
(local to the function).
Calls from JavaScript abort on a pagefault, except for
writable_or_pagefault, which returns a boolean. JS needs to check
before calling any function that may pagefault.
This commit does not yet pervasively apply return_on_pagefault!, this
will be added in the next commit.
Jitted code does not yet properly handle the new form of page faults,
this will be added in a later commit.
This commit contains the final changes requires for porting all C code
to Rust and from emscripten to llvm:
- tools/wasm-patch-indirect-function-table.js: A script that rewrites
the wasm generated by llvm to remove the table limit
- tools/rust-lld-wrapper: A wrapper around rust-lld that removes
arguments forced by rustc that break compilation for us
- src/rust/cpu2/Makefile: A monstrosity to postprocess c2rust's output
- gen/generate_interpreter.js: Ported to produce Rust instead of C
- src/rust/*: A few functions and macros to connect the old Rust code
and the new Rust code
- src/*.js: Removes the loading of the old emscripten wasm module and
adapts imports and exports from emscripten to llvm
