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docs: rewrite architecture.txt + fix mem offsets

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architecture.txt drifted from code: missing HASH_SCRATCH region,
runtime-trait box, wordlists/search-order, codegen locals layout,
F: locals, quotations, crypto. Rewrite from current source.

memory.rs `// 0x...` annotations were the drift source — RETURN
/ FLOAT / HASH / DICT bases printed values disagreeing with the
const arithmetic. Recompute and correct.
This commit is contained in:
Oleksandr Kozachuk
2026-04-16 20:51:12 +02:00
parent 1a8f27b5bd
commit 49582f7e86
2 changed files with 338 additions and 166 deletions
Download Patch File Download Diff File Expand all files Collapse all files
crates/core/src/memory.rs
+4 -4
View File
@@ -50,23 +50,23 @@ pub const DATA_STACK_BASE: u32 = WORD_BUF_BASE + WORD_BUF_SIZE; // 0x0600
pub const DATA_STACK_SIZE: u32 = 4096; // 1024 cells pub const DATA_STACK_SIZE: u32 = 4096; // 1024 cells
/// Return stack region. Grows downward. /// Return stack region. Grows downward.
pub const RETURN_STACK_BASE: u32 = DATA_STACK_BASE + DATA_STACK_SIZE; // 0x1540 pub const RETURN_STACK_BASE: u32 = DATA_STACK_BASE + DATA_STACK_SIZE; // 0x1600
/// Size of return stack region. /// Size of return stack region.
pub const RETURN_STACK_SIZE: u32 = 4096; pub const RETURN_STACK_SIZE: u32 = 4096;
/// Floating-point stack region (fallback). Grows downward. /// Floating-point stack region (fallback). Grows downward.
pub const FLOAT_STACK_BASE: u32 = RETURN_STACK_BASE + RETURN_STACK_SIZE; // 0x2540 pub const FLOAT_STACK_BASE: u32 = RETURN_STACK_BASE + RETURN_STACK_SIZE; // 0x2600
/// Size of float stack region. /// Size of float stack region.
pub const FLOAT_STACK_SIZE: u32 = 2048; // 256 doubles pub const FLOAT_STACK_SIZE: u32 = 2048; // 256 doubles
/// Hash scratch region — output buffer for `SHA1`/`SHA256`/`SHA512` and /// Hash scratch region — output buffer for `SHA1`/`SHA256`/`SHA512` and
/// other hash host words. Sized for the largest supported digest (SHA512 = 64 B). /// other hash host words. Sized for the largest supported digest (SHA512 = 64 B).
pub const HASH_SCRATCH_BASE: u32 = FLOAT_STACK_BASE + FLOAT_STACK_SIZE; // 0x2D40 pub const HASH_SCRATCH_BASE: u32 = FLOAT_STACK_BASE + FLOAT_STACK_SIZE; // 0x2E00
/// Size of hash scratch region. /// Size of hash scratch region.
pub const HASH_SCRATCH_SIZE: u32 = 128; pub const HASH_SCRATCH_SIZE: u32 = 128;
/// Dictionary region start. Grows upward. /// Dictionary region start. Grows upward.
pub const DICTIONARY_BASE: u32 = HASH_SCRATCH_BASE + HASH_SCRATCH_SIZE; // 0x2DC0 pub const DICTIONARY_BASE: u32 = HASH_SCRATCH_BASE + HASH_SCRATCH_SIZE; // 0x2E80
/// Initial top of data stack (grows down from here). /// Initial top of data stack (grows down from here).
pub const DATA_STACK_TOP: u32 = DATA_STACK_BASE + DATA_STACK_SIZE; pub const DATA_STACK_TOP: u32 = DATA_STACK_BASE + DATA_STACK_SIZE;
tools/architecture.txt
+334 -162
View File
@@ -1,6 +1,11 @@
WAFER Architecture Reference (updated 2026-04-13) WAFER Architecture Reference (updated 2026-04-16)
=================================================== ===================================================
WAFER = WebAssembly Forth Engine in Rust. Optimizing Forth-2012 compiler that
emits WASM at run time. Each colon definition becomes its own WASM module that
shares memory, globals, and a function table with every other word.
1. COMPILATION PIPELINE 1. COMPILATION PIPELINE
----------------------- -----------------------
@@ -11,96 +16,134 @@ WAFER Architecture Reference (updated 2026-04-13)
+--------------------------------------------+ +--------------------------------------------+
| Tokenizer: whitespace-delimited words | | Tokenizer: whitespace-delimited words |
| For each token: | | For each token: |
| 1. Dictionary lookup (find) | | 1. Dictionary lookup (HashMap + wordlist |
| 2. If found + interpret mode: EXECUTE | | search order) |
| 3. If found + compile mode: | | 2. Found + interpret mode: EXECUTE |
| - Immediate? Execute now | | 3. Found + compile mode: |
| - IMMEDIATE? Execute now |
| - Normal? Append Call(WordId) to IR | | - Normal? Append Call(WordId) to IR |
| 4. Not found: try parse as number | | 4. Not found: try parse as number |
| - Interpret: push to data stack | | - Interpret: push to data stack |
| - Compile: append PushI32(n) to IR | | - Compile: append PushI32/64/F64 |
| 5. Neither: error "unknown word" | | 5. Neither: error "unknown word" |
| Special cases handled here, not via IR: |
| defining words (CREATE, VARIABLE, :), |
| DOES> dispatch, S" / ." string parsing, |
| {: ... :} locals, [: ... ;] quotations. |
+--------------------------------------------+ +--------------------------------------------+
| On `;` (end of colon definition): | On `;` (end of colon definition):
v v
Optimizer (optimizer.rs) Optimizer (optimizer.rs) — IR -> IR
+--------------------------------------------+ +--------------------------------------------+
| Phase 1: Simplify | | Phase 1 simplify: |
| Peephole -> Constant Fold -> | | peephole -> fold -> strength -> peephole |
| Strength Reduce -> Peephole | | Phase 2 inline (max 8 ops) then re-simpl.: |
| Phase 2: Inline then re-simplify | | inline -> peephole -> fold -> strength |
| Inline(max=8) -> Peephole -> | | -> peephole |
| Constant Fold -> Strength Reduce -> | | Phase 3 dead code: dce -> peephole |
| Peephole | | Phase 4 tail calls (must be last) |
| Phase 3: Eliminate dead code | | Total peephole passes: 5 |
| DCE -> Peephole |
| Phase 4: Tail calls (must be last) |
| Tail Call Detect |
+--------------------------------------------+ +--------------------------------------------+
| |
v v
Codegen (codegen.rs) Codegen (codegen.rs) — IR -> WASM bytes
+--------------------------------------------+ +--------------------------------------------+
| IR -> WASM bytecode via wasm-encoder | | wasm-encoder builds one module per word. |
| Each word = one WASM module with: | | Function locals (laid out in order): |
| Imports: emit, memory, dsp, rsp, fsp, | | 0 cached DSP (i32) |
| table | | 1..s scratch i32 (or promoted |
| Types: void () -> (), i32 (i32) -> () | | stack-to-local slots) |
| One defined function (the word body) | | s..f Forth locals from {: ... :} |
| DSP cached in local 0, writeback before | | (i32 then f64) |
| calls, reload after calls | | f..l loop locals: 2 per nested |
| Scratch locals start at index 1 | | DO/?DO (index, limit) |
| DSP write-back before every Call, |
| reload after — keeps host functions and |
| call_indirect targets coherent. |
| Stack-to-local promotion (codegen flag): |
| straight-line + simple control flow |
| words skip the linear-memory data stack |
| entirely; values stay in WASM locals. |
+--------------------------------------------+ +--------------------------------------------+
| |
v v
Runtime trait (runtime.rs) Runtime trait (runtime.rs) — execution backend
+--------------------------------------------+ +--------------------------------------------+
| ForthVM<R: Runtime> — generic over backend | | ForthVM<R: Runtime> generic over backend. |
| Runtime provides: | | Runtime owns: |
| - Memory r/w (mem_read_i32, etc.) | | - shared linear memory (16 pages init) |
| - Globals (get/set_dsp, rsp, fsp) | | - shared funcref table (grows on demand) |
| - Table (ensure_table_size) | | - 3 mutable i32 globals (dsp/rsp/fsp) |
| - instantiate_and_install(wasm_bytes) | | - emit() import bound to output buffer |
| - call_func(fn_index) | | Runtime methods: |
| - register_host_func(fn_index, HostFn) | | mem_read/write_{i32,u8,slice} |
| get/set_{dsp,rsp,fsp} |
| ensure_table_size(n) |
| instantiate_and_install(wasm, fn_index) |
| call_func(fn_index) |
| register_host_func(fn_index, HostFn) |
| | | |
| HostAccess trait — memory/global ops for | | HostAccess trait — same memory/global ops |
| host function callbacks | | exposed to host-fn callbacks; lets one |
| HostFn = Box<dyn Fn(&mut dyn HostAccess)> | | HostFn closure run on either runtime. |
| HostFn = Box<dyn Fn(&mut dyn HostAccess) |
| -> Result<()> + Send + Sync> |
+--------------------------------------------+ +--------------------------------------------+
| | | |
v v v v
NativeRuntime WebRuntime NativeRuntime WebRuntime
(runtime_native.rs) (crates/web/runtime_web.rs) (runtime_native.rs, (crates/web/src/
feature = "native") runtime_web.rs)
+------------------+ +------------------+ +------------------+ +------------------+
| wasmtime Engine | | js_sys::WebAsm | | wasmtime Engine, | | js_sys WebAsm |
| Store, Memory | | Memory, Table | | Store, Memory, | | Memory, Table, |
| Table, Globals | | Global objects | | Table, Globals, | | Global, JS |
| Func closures | | JS Closures | | Func closures | | Closures |
+------------------+ +------------------+ +------------------+ +------------------+
2. MEMORY LAYOUT (Linear Memory) 2. MEMORY LAYOUT (linear memory, single shared instance)
-------------------------------- --------------------------------------------------------
Address Region Size Notes Address Region Size Notes
-------- ------------------ ------- ------------------------- -------- ------------------ ------- --------------------------
0x0000 System Variables 64 B STATE, BASE, >IN, HERE, 0x0000 System Variables 64 B STATE, BASE, >IN, HERE,
LATEST, SOURCE-ID, #TIB, LATEST, SOURCE-ID, #TIB,
HLD, LEAVE-FLAG HLD, LEAVE-FLAG
0x0040 Input Buffer 1024 B Source parsing 0x0040 Input Buffer (TIB) 1024 B Source line being parsed
0x0440 PAD 256 B Scratch area 0x0440 PAD 256 B Scratch for string ops
0x0540 Pictured Output 128 B <# ... #> (grows down) 0x0540 Pictured Output 128 B <# ... #> (HLD grows down)
0x05C0 WORD Buffer 64 B Transient counted string 0x05C0 WORD Buffer 64 B Transient counted string
0x0600 Data Stack 4096 B 1024 cells, grows DOWN 0x0600 Data Stack 4096 B 1024 cells, grows DOWN
0x1600 (Data Stack Top) DSP starts here ^ DSP starts at top = 0x1600
0x1540 Return Stack 4096 B Grows DOWN 0x1600 Return Stack 4096 B Grows DOWN
0x2540 Float Stack 2048 B 256 doubles, grows DOWN ^ RSP starts at top = 0x2600
0x2D40 Dictionary grows UP Linked list of word entries 0x2600 Float Stack 2048 B 256 doubles, grows DOWN
^ FSP starts at top = 0x2E00
0x2E00 Hash Scratch 128 B SHA1/256/512 output
0x2E80 Dictionary grows UP Linked list of entries
Total initial memory: 16 pages = 1 MiB (max 256 pages = 16 MiB) Constants from crates/core/src/memory.rs (authoritative):
Cell size: 4 bytes (i32) SYSVAR_BASE 0x0000 size 64
Float size: 8 bytes (f64) INPUT_BUFFER_BASE 0x0040 size 1024
PAD_BASE 0x0440 size 256
PICT_BUF_BASE 0x0540 size 128
WORD_BUF_BASE 0x05C0 size 64
DATA_STACK_BASE 0x0600 size 4096 (DATA_STACK_TOP = 0x1600)
RETURN_STACK_BASE 0x1600 size 4096 (RETURN_STACK_TOP = 0x2600)
FLOAT_STACK_BASE 0x2600 size 2048 (FLOAT_STACK_TOP = 0x2E00)
HASH_SCRATCH_BASE 0x2E00 size 128
DICTIONARY_BASE 0x2E80 grows up to memory.len()
(Some inline `// 0x...` comments in memory.rs are stale — the
computed values above are correct; the consts are derived.)
Total initial memory: 16 pages = 1 MiB (max 256 pages = 16 MiB).
Cell size: 4 bytes (i32). Float size: 8 bytes (f64).
Stack layout note: linear-memory data and float stacks are the
fallback used whenever the optimizer can't keep values in WASM
locals. After stack-to-local promotion, many words touch DSP
only on entry/exit.
3. SYSTEM VARIABLES (offsets from 0x0000) 3. SYSTEM VARIABLES (offsets from 0x0000)
@@ -113,60 +156,86 @@ WAFER Architecture Reference (updated 2026-04-13)
8 >IN Parse offset into input buffer 8 >IN Parse offset into input buffer
12 HERE Next free dictionary address 12 HERE Next free dictionary address
16 LATEST Most recent dictionary entry addr 16 LATEST Most recent dictionary entry addr
20 SOURCE-ID 0=user input, -1=string 20 SOURCE-ID 0=user input, -1=string, fileid>0
24 #TIB Length of current input 24 #TIB Length of current input
28 HLD Pictured numeric output pointer 28 HLD Pictured numeric output pointer
32 LEAVE-FLAG Nonzero when LEAVE called in loop 32 LEAVE-FLAG Nonzero when LEAVE called in loop
4. DICTIONARY ENTRY FORMAT 4. DICTIONARY (dictionary.rs)
-------------------------- -----------------------------
+--------+-------+----------+---------+-----------+ Entry layout in linear memory:
| Link | Flags | Name | Padding | Code |
| 4 bytes| 1 byte| N bytes | 0-3 B | 4 bytes | +--------+-------+----------+---------+-----------+----------+
+--------+-------+----------+---------+-----------+ | Link | Flags | Name | Padding | Code | Param |
| 4 B | 1 B | N B | 0-3 B | 4 B | optional |
+--------+-------+----------+---------+-----------+----------+
^ ^ ^ ^
entry_addr code field (fn table index) entry_addr code field (fn-table idx)
Flags byte: Flags byte:
Bit 7 (0x80): IMMEDIATE Bit 7 (0x80): IMMEDIATE
Bit 6 (0x40): HIDDEN (during compilation) Bit 6 (0x40): HIDDEN (during compilation)
Bits 0-4 (0x1F): name length (max 31) Bits 0-4 : name length (max 31)
Link points to previous entry (0 = end of list). Link points to previous entry (0 = end of list).
Name stored uppercase, padded to 4-byte alignment. Name stored uppercase, padded to 4-byte alignment.
Code field: index into WASM function table. Code field: index into shared WASM function table.
Parameter field (if any) follows immediately after code field. Parameter field follows the code field for CREATE'd /
DOES> / VARIABLE / CONSTANT bodies.
Lookup is NOT linear: dictionary.rs maintains a HashMap
index from name -> Vec<(wid, addr, fn_index, immediate)>.
Each entry is tagged with its wordlist id; resolution
walks the current search order.
Wordlists / Search-Order:
wordlist ids are u32; the FORTH wordlist is id 1.
`current_wid` selects where new definitions land;
`search_order` is the lookup chain (top first).
Implements the Forth-2012 Search-Order word set.
5. THREE TYPES OF WORDS 5. WORD CATEGORIES
----------------------- ------------------
a) IR Primitives (compiled to WASM) a) IR Primitives — register_primitive("DUP", false, vec![IrOp::Dup])
register_primitive("DUP", false, vec![IrOp::Dup])
- Body stored as Vec<IrOp> - Body stored as Vec<IrOp>
- Optimized, then compiled to WASM module - Optimized, then compiled to WASM
- Inlineable by optimizer - Inlineable by optimizer
- FAST: no function call overhead when inlined - Batched at boot: ~110 primitive registrations compiled
into a single WASM module to amortize instantiation cost
b) Host Functions (HostFn closures) b) Host Functions — register_host_primitive(".", false, func)
register_host_primitive(".", false, func) - HostFn = Box<dyn Fn(&mut dyn HostAccess)
- HostFn = Box<dyn Fn(&mut dyn HostAccess) -> Result<()>> -> Result<()> + Send + Sync>
- Access memory/globals via HostAccess trait (runtime-agnostic) - Access memory/globals via HostAccess trait
- NOT inlineable - NOT inlineable
- Used for: I/O, dictionary manipulation, complex logic - Used for I/O, dictionary manipulation, complex stack ops
- Same closure works on NativeRuntime and WebRuntime - Same closure runs on NativeRuntime and WebRuntime
c) Forth-defined words c) Forth-defined words — `: SQUARE DUP * ;`
: SQUARE DUP * ; - Compiled by the outer interpreter
- Compiled by outer interpreter - Goes through the full optimize -> codegen pipeline
- Goes through full optimize -> codegen pipeline - Stored in `ir_bodies` for future inlining
- Stored in ir_bodies for future inlining
d) Special interpreter tokens (immediate, with custom parsing)
- Defining words: CREATE, VARIABLE, CONSTANT, :, ;, DOES>
- String literals: S", ."
- Control structures: IF/ELSE/THEN, BEGIN/UNTIL/WHILE/REPEAT,
DO/?DO/LOOP/+LOOP, [: ... ;] quotations, {: ... :} locals
- CONSOLIDATE
Their body-collection / dictionary-side-effect logic lives
directly in compile_token / interpret_token_immediate.
They still emit IR ops (e.g. IrOp::If, IrOp::DoLoop,
IrOp::ForthLocalGet) — the difference is that they are NOT
registered via register_primitive; the outer interpreter
handles them as special syntax.
6. WASM MODULE STRUCTURE (per word) 6. WASM MODULE STRUCTURE (per JIT-compiled word)
----------------------------------- ------------------------------------------------
Imports (6) — provided by Runtime impl: Imports (6) — provided by Runtime impl:
0. emit (func: i32 -> void) Character output callback 0. emit (func: i32 -> void) Character output callback
@@ -176,25 +245,59 @@ WAFER Architecture Reference (updated 2026-04-13)
4. fsp (global: mut i32) Float stack pointer 4. fsp (global: mut i32) Float stack pointer
5. table (table: funcref) Shared function table 5. table (table: funcref) Shared function table
Types (2): Types: () -> () for word bodies; (i32) -> () for emit.
0. void: () -> ()
1. i32: (i32) -> ()
Functions (1): Functions (1):
The compiled word body The compiled word body, typed () -> ().
Element section: Element section:
table[base_fn_index] = function 1 table[base_fn_index] = function 1
Runtime::instantiate_and_install(wasm_bytes, fn_index): Runtime::instantiate_and_install(wasm_bytes, fn_index):
- NativeRuntime: Module::new + Instance::new with 6 wasmtime imports - NativeRuntime: wasmtime Module::new + Instance::new
- WebRuntime: WebAssembly.instantiate with JS import objects with the 6 imports above
- WebRuntime: WebAssembly.instantiate with JS import
objects pulled from the shared WaferRepl state
7. OPTIMIZATION PASSES (detail) 7. IR OPS (ir.rs — IrOp enum)
-----------------------------
Stack: Drop, Dup, Swap, Over, Rot, Nip, Tuck,
TwoDup, TwoDrop
Literals: PushI32, PushI64, PushF64
Arithmetic: Add, Sub, Mul, DivMod, Negate, Abs
Compare: Eq, NotEq, Lt, Gt, LtUnsigned,
ZeroEq, ZeroLt
Logic: And, Or, Xor, Invert,
Lshift, Rshift, ArithRshift
Memory: Fetch, Store, CFetch, CStore, PlusStore
Control: Call, TailCall, Exit,
If{then, else?},
DoLoop{body, is_plus_loop},
BeginUntil, BeginAgain,
BeginWhileRepeat,
BeginDoubleWhileRepeat,
LoopRestartIfFalse,
Block(label), BranchIfFalse(label),
EndBlock(label) -- for CS-ROLL'd patterns
Return stack: ToR, FromR, RFetch, LoopJ
Forth locals: ForthLocalGet/Set,
ForthFLocalGet/Set
I/O: Emit, Dot, Cr, Type
System: Execute, SpFetch
Float stack: FDup, FDrop, FSwap, FOver
Float math: FAdd, FSub, FMul, FDiv, FNegate, FAbs,
FSqrt, FMin, FMax, FFloor, FRound
Float compare:FZeroEq, FZeroLt, FEq, FLt
Float memory: FetchFloat, StoreFloat
Conversion: StoF, FtoS
8. OPTIMIZATION PASSES (detail)
------------------------------- -------------------------------
PEEPHOLE (runs 5x across full pipeline): PEEPHOLE (5x across pipeline):
PushI32(n), Drop -> (removed) Unused literal PushI32(n), Drop -> (removed) Unused literal
Dup, Drop -> (removed) Redundant copy Dup, Drop -> (removed) Redundant copy
Swap, Swap -> (removed) Self-inverse Swap, Swap -> (removed) Self-inverse
@@ -205,16 +308,17 @@ WAFER Architecture Reference (updated 2026-04-13)
PushI32(1), Mul -> (removed) Identity PushI32(1), Mul -> (removed) Identity
Over, Over -> TwoDup Combine Over, Over -> TwoDup Combine
Drop, Drop -> TwoDrop Combine Drop, Drop -> TwoDrop Combine
(+ float variants: PushF64/FDrop, FDup/FDrop, FSwap/FSwap, FNegate/FNegate) Float variants:
PushF64(_), FDrop / FDup, FDrop /
FSwap, FSwap / FNegate, FNegate
CONSTANT FOLD: CONSTANT FOLD:
Binary: PushI32(a), PushI32(b), <op> -> PushI32(result) Binary i32: PushI32(a), PushI32(b), <op> -> PushI32(r)
Supports: Add, Sub, Mul, And, Or, Xor, Lshift, Rshift, ArithRshift, Add, Sub, Mul, And, Or, Xor,
Eq, NotEq, Lt, Gt, LtUnsigned Lshift, Rshift, ArithRshift,
Unary: PushI32(n), <op> -> PushI32(result) Eq, NotEq, Lt, Gt, LtUnsigned
Supports: Negate, Abs, Invert, ZeroEq, ZeroLt Unary i32: Negate, Abs, Invert, ZeroEq, ZeroLt
Float binary: PushF64(a), PushF64(b), <op> -> PushF64(result) Float binary/unary equivalents on PushF64.
Float unary: PushF64(n), <op> -> PushF64(result)
STRENGTH REDUCE: STRENGTH REDUCE:
PushI32(2^n), Mul -> PushI32(n), Lshift PushI32(2^n), Mul -> PushI32(n), Lshift
@@ -222,85 +326,153 @@ WAFER Architecture Reference (updated 2026-04-13)
PushI32(0), Lt -> ZeroLt PushI32(0), Lt -> ZeroLt
DCE: DCE:
PushI32(nonzero), If{then,else} -> then_body only PushI32(nonzero), If{then,else} -> then_body only
PushI32(0), If{then,else} -> else_body only PushI32(0), If{then,else} -> else_body only
Everything after Exit -> removed Everything after Exit -> removed
INLINE (max_size=8, single pass): INLINE (max 8 ops, single pass):
Call(id) -> inline body if: Call(id) -> body if all of:
- Body length <= 8 ops - body length <= 8 ops
- No self-recursion - no self-recursion
- No Exit (would return from caller) - no Exit (would return from caller)
- No ForthLocalGet/Set (would collide with caller's locals) - no ForthLocalGet/Set (would collide with caller locals)
TailCall -> Call when inlined (no longer tail position) TailCall -> Call when inlined (no longer tail position)
TAIL CALL (last pass): TAIL CALL (last pass, must be last):
Last Call(id) -> TailCall(id) if: trailing Call(id) -> TailCall(id) if return stack balanced
- Return stack balanced (equal ToR and FromR) (equal ToR / FromR pairs).
Recurses into If branches for conditional tail calls Recurses into If branches for conditional tail calls.
STACK-TO-LOCAL PROMOTION (codegen pass, not optimizer):
Words whose effects on the data stack can be statically
tracked are compiled to use WASM locals 1..s instead of
DSP loads/stores. Triggered by `is_promotable(body)`.
DSP is still written back before any Call so callees and
host functions see a consistent stack.
8. CONSOLIDATION 9. CONSOLIDATION (consolidate.rs + codegen.rs)
---------------- ----------------------------------------------
CONSOLIDATE word recompiles all JIT-compiled words into a CONSOLIDATE recompiles every JIT-compiled word into ONE WASM
single WASM module: module:
- All call_indirect -> direct call (for words in module) - All call_indirect to consolidated words become direct
- External calls (host functions) remain call_indirect `call` (single-module direct calls)
- Maximum performance for final program - External calls (host functions) stay call_indirect
- Removes per-word instantiation overhead and lets the
WASM engine inline / specialize across word boundaries
Two-part implementation: Two parts:
codegen::compile_consolidated_module() - builds multi-function module codegen::compile_consolidated_module()
outer::ForthVM::consolidate() - orchestrates collection + table update Builds the multi-function module.
outer::ForthVM::consolidate()
Collects ir_bodies, computes table layout, compiles,
instantiates, and patches the shared function table.
9. EXPORT PIPELINE (wafer build) 10. EXPORT PIPELINE (`wafer build`)
-------------------------------- ----------------------------------
1. Evaluate source file with recording_toplevel=true export.rs::export_module() steps:
2. Collect all IR words + top-level IR 1. Evaluate the source file with recording_toplevel = true
3. Determine entry: --entry flag > MAIN word > top-level execution 2. Collect every IR word + recorded top-level IR
4. Build consolidated module with data section (memory snapshot) 3. Resolve entry point (priority):
5. Embed metadata in "wafer" custom section (JSON) --entry <name> > MAIN > synthetic _start from the
6. Optional: --js generates JS loader + HTML page recorded top-level
7. Optional: --native AOT-compiles and appends to wafer binary 4. Snapshot WASM linear memory (system vars + dictionary +
Format: [wafer binary][precompiled WASM][metadata][trailer] any user data)
Trailer: payload_len(8) + metadata_len(8) + "WAFEREXE"(8) 5. Walk the IR, find every Call/TailCall to a host word
not in the consolidated set: those become required
imports of the exported module
6. Build metadata (JSON, custom "wafer" section):
version, entry_table_index, host_functions,
memory_size, dsp/rsp/fsp_init
7. compile_exportable_module() emits the final WASM with
a passive data section seeded from the memory snapshot
8. Optional --js: also emit a JS loader + minimal HTML
9. Optional --native: AOT-compile and append to the wafer
binary itself, in this layout:
[wafer ELF/Mach-O][precompiled WASM][metadata]
[trailer: payload_len(8) | metadata_len(8) | "WAFEREXE"]
The CLI detects the trailer at startup and runs the
embedded payload directly (single-file distribution).
10. CRATE STRUCTURE 11. CRATE STRUCTURE
------------------- -------------------
crates/ crates/
core/ wafer-core: compiler, optimizer, codegen, dictionary, Runtime trait core/ wafer-core: compiler, optimizer, codegen,
Feature flags: default=["native"], "native" enables wasmtime dictionary, runtime trait, outer interpreter.
Without features: pure Rust (dictionary, IR, optimizer, codegen, outer) Largest file: codegen.rs (~4.3k LOC).
cli/ wafer: CLI REPL (rustyline), wafer build/run commands Feature flags:
web/ wafer-web: browser REPL (wasm-bindgen + WebRuntime + HTML/CSS/JS) default = ["native"]
"native" pulls in wasmtime + NativeRuntime +
runner.rs (CLI executor) + export.rs
"crypto" enables SHA1/256/512 host words
No features: pure-Rust core for wafer-web
(dictionary, IR, optimizer, codegen,
outer interpreter only)
cli/ wafer: rustyline REPL + `wafer build` / `wafer run`
web/ wafer-web: browser REPL.
Key web files: Key web files:
crates/web/src/lib.rs WaferRepl wasm-bindgen entry point crates/web/src/lib.rs WaferRepl wasm-bindgen entry
crates/web/src/runtime_web.rs WebRuntime: js_sys WebAssembly API crates/web/src/runtime_web.rs WebRuntime: js_sys WebAssembly
crates/web/www/app.js Frontend JS (terminal emulation) crates/web/www/app.js Frontend (terminal emulation)
crates/web/www/index.html HTML shell crates/web/www/index.html HTML shell
crates/web/www/style.css Styling crates/web/www/style.css Styling
crates/web/www/pkg/ wasm-pack output (gitignored)
11. BOOT SEQUENCE 12. BOOT SEQUENCE
----------------- -----------------
ForthVM::<R>::new() -> ForthVM::<R>::new() ->
1. R::new() — create runtime (wasmtime or browser WASM) 1. R::new() — create runtime (wasmtime or browser WASM)
2. register_primitives() in batch_mode: 2. register_primitives() in batch_mode = true:
- ~40 IR primitives (DUP, +, @, etc.) - ~110 IR primitive registrations (DUP, +, @, ...)
- ~60 host functions (., .S, M*, ACCEPT, etc.) - ~87 host primitive registrations (., .S, M*, ACCEPT, ...)
- ~30 special words (IF, DO, :, VARIABLE, etc.) - special interpreter tokens (IF, DO, :, VARIABLE, S",
3. compile_batch() - single WASM module for all IR primitives {: :}, [: ;], CONSOLIDATE, ...) handled directly in
4. Load boot.fth - Forth replaces Rust host functions: interpret_token_immediate / compile_token, no IR op
Phase 1: Stack/memory (DEPTH, PICK, 2OVER, FILL, MOVE) 3. Word-set registrations:
Phase 2: Double-cell arithmetic (D+, DNEGATE, D<) core, double, exception, facility, file (subset),
Phase 3: Mixed arithmetic (SM/REM, FM/MOD, */, */MOD) floating-point, locals, memory, search-order,
Phase 4: HERE, ALLOT, comma, ALIGN programming-tools, string, optional crypto
Phase 5: I/O, pictured numeric output (., U., TYPE, <# # #>) 4. batch_compile_deferred() — single WASM module for all
Phase 6: DEFER support deferred IR primitives
Phase 7: String operations (COMPARE, SOURCE, FALIGNED) 5. Load boot.fth (include_str!), evaluated line by line so
`\` comments terminate at end-of-line:
Phase 1: stack/memory (DEPTH, PICK, 2OVER, FILL, MOVE,
CMOVE, /STRING, -TRAILING)
Phase 2: double-cell arithmetic (D+, DNEGATE, D<, D=)
Phase 3: mixed arithmetic (SM/REM, FM/MOD, */, */MOD)
Phase 4: HERE, ALLOT, comma, ALIGN, ALIGNED
Phase 5: I/O + pictured output (., U., TYPE, <# # #>,
SIGN, HOLD)
Phase 6: DEFER support (DEFER, IS, ACTION-OF)
Phase 7: more replacements (COMPARE, SOURCE, FALIGNED,
DFALIGN, structures, S" hint, ...)
13. RUNTIME-VS-EXPORT NOTE
--------------------------
Two separate codegen entry points produce multi-function
WASM modules from the same IR:
compile_consolidated_module() used by CONSOLIDATE
- Targets the live runtime
- Re-uses the shared globals/table/memory imports
- External calls remain call_indirect
compile_exportable_module() used by `wafer build`
- Targets a standalone module
- Carries its own memory (passive data section seeded
from the snapshot) and embeds metadata
- Required host functions become imports the runner
(or AOT loader) must satisfy
Both share the same per-IrOp lowering helpers; the
difference is in module-level wiring.