From fafaf423b43f0408438860e3af57520633702057 Mon Sep 17 00:00:00 2001
From: dcodeIO <dcode@dcode.io>
Date: Thu, 19 Jul 2018 16:15:56 +0200
Subject: [PATCH] Make an interface around gc.* fwiw

---
 std/assembly/allocator/arena.ts      |  6 +-
 std/assembly/allocator/buddy.ts      | 13 ++--
 std/assembly/allocator/emscripten.ts | 13 ++--
 std/assembly/allocator/system.ts     | 13 ++--
 std/assembly/allocator/tlsf.ts       | 11 ++--
 std/assembly/collector/itcm.ts       | 92 +++++++++++++++-------------
 std/assembly/gc.ts                   | 23 +++++++
 std/assembly/index.d.ts              | 14 +++++
 tests/binaryen/const-expr.js         | 29 +++++++++
 tests/binaryen/const-expr.wat        | 19 ++++++
 tests/compiler/std/gc.optimized.wat  | 16 +++--
 tests/compiler/std/gc.ts             |  4 +-
 tests/compiler/std/gc.untouched.wat  | 28 ++++++---
 13 files changed, 183 insertions(+), 98 deletions(-)
 create mode 100644 tests/binaryen/const-expr.js
 create mode 100644 tests/binaryen/const-expr.wat

diff --git a/std/assembly/allocator/arena.ts b/std/assembly/allocator/arena.ts
index 8adb8485..19042e99 100644
--- a/std/assembly/allocator/arena.ts
+++ b/std/assembly/allocator/arena.ts
@@ -12,6 +12,8 @@ import { AL_MASK, MAX_SIZE_32 } from "../internal/allocator";
 var startOffset: usize = (HEAP_BASE + AL_MASK) & ~AL_MASK;
 var offset: usize = startOffset;
 
+// Memory allocator interface
+
 @global
 export function __memory_allocate(size: usize): usize {
   if (size) {
@@ -35,9 +37,7 @@ export function __memory_allocate(size: usize): usize {
 }
 
 @global
-export function __memory_free(ptr: usize): void {
-  // nop
-}
+export function __memory_free(ptr: usize): void { /* nop */ }
 
 @global
 export function __memory_reset(): void {
diff --git a/std/assembly/allocator/buddy.ts b/std/assembly/allocator/buddy.ts
index 7157dd83..2aea2240 100644
--- a/std/assembly/allocator/buddy.ts
+++ b/std/assembly/allocator/buddy.ts
@@ -338,8 +338,9 @@ function lower_bucket_limit(bucket: usize): u32 {
   return 1;
 }
 
-@global
-export function __memory_allocate(request: usize): usize {
+// Memory allocator interface
+
+@global export function __memory_allocate(request: usize): usize {
   var original_bucket: usize, bucket: usize;
 
   /*
@@ -473,8 +474,7 @@ export function __memory_allocate(request: usize): usize {
   return 0;
 }
 
-@global
-export function __memory_free(ptr: usize): void {
+@global export function __memory_free(ptr: usize): void {
   var bucket: usize, i: usize;
 
   /*
@@ -538,8 +538,3 @@ export function __memory_free(ptr: usize): void {
    */
   list_push(buckets$get(bucket), changetype<List>(ptr_for_node(i, bucket)));
 }
-
-@global
-export function __memory_reset(): void {
-  unreachable();
-}
diff --git a/std/assembly/allocator/emscripten.ts b/std/assembly/allocator/emscripten.ts
index f3c63f44..92956b76 100644
--- a/std/assembly/allocator/emscripten.ts
+++ b/std/assembly/allocator/emscripten.ts
@@ -11,17 +11,12 @@
 declare function _malloc(size: usize): usize;
 declare function _free(ptr: usize): void;
 
-@global
-export function __memory_allocate(size: usize): usize {
+// Memory allocator interface
+
+@global export function __memory_allocate(size: usize): usize {
   return _malloc(size);
 }
 
-@global
-export function __memory_free(ptr: usize): void {
+@global export function __memory_free(ptr: usize): void {
   _free(ptr);
 }
-
-@global
-export function __memory_reset(): void {
-  unreachable();
-}
diff --git a/std/assembly/allocator/system.ts b/std/assembly/allocator/system.ts
index eeaf552f..76b3293b 100644
--- a/std/assembly/allocator/system.ts
+++ b/std/assembly/allocator/system.ts
@@ -10,17 +10,12 @@
 declare function malloc(size: usize): usize;
 declare function free(ptr: usize): void;
 
-@global
-export function __memory_allocate(size: usize): usize {
+// Memory allocator interface
+
+@global export function __memory_allocate(size: usize): usize {
   return malloc(size);
 }
 
-@global
-export function __memory_free(ptr: usize): void {
+@global export function __memory_free(ptr: usize): void {
   free(ptr);
 }
-
-@global
-export function __memory_reset(): void {
-  unreachable();
-}
diff --git a/std/assembly/allocator/tlsf.ts b/std/assembly/allocator/tlsf.ts
index bf040141..fda68cfa 100644
--- a/std/assembly/allocator/tlsf.ts
+++ b/std/assembly/allocator/tlsf.ts
@@ -433,11 +433,10 @@ function fls<T>(word: T): T {
 /** Reference to the initialized {@link Root} structure, once initialized. */
 var ROOT: Root = changetype<Root>(0);
 
-// External interface
+// Memory allocator interface
 
 /** Allocates a chunk of memory. */
-@global
-export function __memory_allocate(size: usize): usize {
+@global export function __memory_allocate(size: usize): usize {
 
   // initialize if necessary
   var root = ROOT;
@@ -490,8 +489,7 @@ export function __memory_allocate(size: usize): usize {
 }
 
 /** Frees the chunk of memory at the specified address. */
-@global
-export function __memory_free(data: usize): void {
+@global export function __memory_free(data: usize): void {
   if (data) {
     let root = ROOT;
     if (root) {
@@ -504,7 +502,6 @@ export function __memory_free(data: usize): void {
   }
 }
 
-@global
-export function __memory_reset(): void {
+@global export function __memory_reset(): void {
   unreachable();
 }
diff --git a/std/assembly/collector/itcm.ts b/std/assembly/collector/itcm.ts
index 4bbef614..691e34c9 100644
--- a/std/assembly/collector/itcm.ts
+++ b/std/assembly/collector/itcm.ts
@@ -11,10 +11,6 @@ import {
   MAX_SIZE_32
 } from "../internal/allocator";
 
-import {
-  __gc_iterate_roots
-} from "../builtins";
-
 // ╒═══════════════ Managed object layout (32-bit) ════════════════╕
 //    3                   2                   1
 //  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0  bits
@@ -145,7 +141,7 @@ var set2: ManagedObject;
 var iter: ManagedObject;
 
 /** Performs a single step according to the current state. */
-function gc_step(): void {
+function step(): void {
   var obj: ManagedObject;
   switch (state) {
     case State.INIT: {
@@ -158,7 +154,7 @@ function gc_step(): void {
     }
     case State.IDLE: {
       // start by marking roots
-      __gc_iterate_roots(function mark_root(ref: usize): void {
+      gc.iterateRoots(function mark_root(ref: usize): void {
         if (ref) {
           let obj = changetype<ManagedObject>(ref - ManagedObject.SIZE);
           obj.makeBlack();
@@ -202,42 +198,50 @@ function gc_step(): void {
   }
 }
 
-/** Garbage collector interface. */
-@global
-export namespace gc {
-
-  /** Allocates a managed object. */
-  export function alloc(
-    size: usize,
-    visitFn: (ref: usize) => void
-  ): usize {
-    assert(size <= MAX_SIZE_32 - ManagedObject.SIZE);
-    var obj = changetype<ManagedObject>(memory.allocate(ManagedObject.SIZE + size));
-    obj.makeWhite();
-    obj.visitFn = visitFn;
-    set1.insert(obj);
-    return changetype<usize>(obj) + ManagedObject.SIZE;
-  }
-
-  /** Visits a reachable object. Called from the visitFn functions. */
-  export function visit(obj: ManagedObject): void {
-    if (state == State.SWEEP) return;
-    if (obj.isWhite) obj.makeGray();
-  }
-
-  /** References a managed child object from its parent object. */
-  export function ref(parent: ManagedObject, child: ManagedObject): void {
-    if (parent.isBlack && child.isWhite) parent.makeGray();
-  }
-
-  /** Performs a full garbage collection cycle. */
-  export function collect(): void {
-    // begin collecting if not yet collecting
-    switch (state) {
-      case State.INIT:
-      case State.IDLE: gc_step();
-    }
-    // finish the cycle
-    while (state != State.IDLE) gc_step();
-  }
+@inline function refToObj(ref: usize): ManagedObject {
+  return changetype<ManagedObject>(ref - ManagedObject.SIZE);
+}
+
+@inline function objToRef(obj: ManagedObject): usize {
+  return changetype<usize>(obj) + ManagedObject.SIZE;
+}
+
+// Garbage collector interface
+
+/** Allocates a managed object. */
+@global export function __gc_allocate(
+  size: usize,
+  visitFn: (ref: usize) => void
+): usize {
+  assert(size <= MAX_SIZE_32 - ManagedObject.SIZE);
+  var obj = changetype<ManagedObject>(memory.allocate(ManagedObject.SIZE + size));
+  obj.makeWhite();
+  obj.visitFn = visitFn;
+  set1.insert(obj);
+  return objToRef(obj);
+}
+
+/** Marks a reachable object. Called from the visitFn functions. */
+@global export function __gc_mark(ref: usize): void {
+  var obj = refToObj(ref);
+  if (state == State.SWEEP) return;
+  if (obj.isWhite) obj.makeGray();
+}
+
+/** Links a managed child object to its parent object. */
+@global export function __gc_link(parentRef: usize, childRef: usize): void {
+  var parent = refToObj(parentRef);
+  var child = refToObj(childRef);
+  if (parent.isBlack && child.isWhite) parent.makeGray();
+}
+
+/** Performs a full garbage collection cycle. */
+@global export function __gc_collect(): void {
+  // begin collecting if not yet collecting
+  switch (state) {
+    case State.INIT:
+    case State.IDLE: step();
+  }
+  // finish the cycle
+  while (state != State.IDLE) step();
 }
diff --git a/std/assembly/gc.ts b/std/assembly/gc.ts
index 59a72904..fbe72028 100644
--- a/std/assembly/gc.ts
+++ b/std/assembly/gc.ts
@@ -2,4 +2,27 @@ export namespace gc {
 
   @builtin export declare function iterateRoots(fn: (ref: usize) => void): void; // tslint:disable-line
 
+  export function allocate(size: usize, visitFn: (ref: usize) => void): usize {
+    if (isDefined(__gc_allocate)) return __gc_allocate(size, visitFn); // tslint:disable-line
+    WARNING("Calling 'gc.allocate' requires a garbage collector to be present.");
+    return <usize>unreachable();
+  }
+
+  export function mark(ref: usize): void {
+    if (isDefined(__gc_mark)) return __gc_mark(ref); // tslint:disable-line
+    WARNING("Calling 'gc.mark' requires a garbage collector to be present.");
+    unreachable();
+  }
+
+  export function link(parentRef: usize, childRef: usize): void {
+    if (isDefined(__gc_link)) return __gc_link(parentRef, childRef); // tslint:disable-line
+    WARNING("Calling 'gc.link' requires a garbage collector to be present.");
+    unreachable();
+  }
+
+  export function collect(): void {
+    if (isDefined(__gc_collect)) return __gc_collect(); // tslint:disable-line
+    WARNING("Calling 'gc.collect' requires a garbage collector to be present.");
+    unreachable();
+  }
 }
diff --git a/std/assembly/index.d.ts b/std/assembly/index.d.ts
index 9a0b1096..5777a0bc 100644
--- a/std/assembly/index.d.ts
+++ b/std/assembly/index.d.ts
@@ -348,6 +348,20 @@ declare namespace memory {
   export function reset(): void;
 }
 
+/** Garbage collector operations. */
+declare namespace gc {
+  /** Calls the specified function with every reference within the root set. */
+  export function iterateRoots(fn: (ref: usize) => void): void;
+  /** Allocates a managed object identified by its visitor function. */
+  export function allocate(size: usize, visitFn: (ref: usize) => void): usize;
+  /** Marks a managed object as reachable. */
+  export function mark(ref: usize): void;
+  /** Links a managed child with its parent. */
+  export function link(parentRef: usize, childRef: usize): void;
+  /** Performs a full garbage collection cycle. */
+  export function collect(): void;
+}
+
 /** Table operations. */
 declare namespace table {
   /** Copies elements from a passive element segment to a table. */
diff --git a/tests/binaryen/const-expr.js b/tests/binaryen/const-expr.js
new file mode 100644
index 00000000..61b3ddca
--- /dev/null
+++ b/tests/binaryen/const-expr.js
@@ -0,0 +1,29 @@
+var binaryen = require("binaryen");
+
+var mod = new binaryen.Module();
+
+var addType = mod.addFunctionType("iii", binaryen.i32, [ binaryen.i32, binaryen.i32 ]);
+mod.addFunction("add", addType, [],
+  mod.i32.add(
+    mod.get_local(0, binaryen.i32),
+    mod.get_local(1, binaryen.i32)
+  )
+);
+mod.addFunctionExport("add", "add");
+
+var testType = mod.addFunctionType("i", binaryen.i32, []);
+mod.addFunction("test", testType, [],
+  mod.call("add", [
+    mod.i32.const(1),
+    mod.i32.const(2)
+  ], binaryen.i32)
+);
+mod.addFunctionExport("test", "test");
+
+binaryen.setOptimizeLevel(4);
+binaryen.setShrinkLevel(0);
+binaryen.setDebugInfo(false);
+mod.runPasses(["precompute"]);
+if (!mod.validate())
+  console.log("-> does not validate");
+console.log(mod.emitText());
diff --git a/tests/binaryen/const-expr.wat b/tests/binaryen/const-expr.wat
new file mode 100644
index 00000000..936b198e
--- /dev/null
+++ b/tests/binaryen/const-expr.wat
@@ -0,0 +1,19 @@
+(module
+ (type $iii (func (param i32 i32) (result i32)))
+ (type $i (func (result i32)))
+ (export "add" (func $add))
+ (export "test" (func $test))
+ (func $add (; 0 ;) (type $iii) (param $0 i32) (param $1 i32) (result i32)
+  (i32.add
+   (get_local $0)
+   (get_local $1)
+  )
+ )
+ (func $test (; 1 ;) (type $i) (result i32)
+  (call $add
+   (i32.const 1)
+   (i32.const 2)
+  )
+ )
+)
+
diff --git a/tests/compiler/std/gc.optimized.wat b/tests/compiler/std/gc.optimized.wat
index 67b5bea4..b1527fb1 100644
--- a/tests/compiler/std/gc.optimized.wat
+++ b/tests/compiler/std/gc.optimized.wat
@@ -167,7 +167,7 @@
    (get_local $1)
   )
  )
- (func $~lib/collector/itcm/gc.alloc (; 7 ;) (type $iii) (param $0 i32) (param $1 i32) (result i32)
+ (func $~lib/collector/itcm/__gc_allocate (; 7 ;) (type $iii) (param $0 i32) (param $1 i32) (result i32)
   (local $2 i32)
   (if
    (i32.gt_u
@@ -178,8 +178,8 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 8)
-     (i32.const 214)
-     (i32.const 4)
+     (i32.const 216)
+     (i32.const 2)
     )
     (unreachable)
    )
@@ -207,7 +207,13 @@
    (i32.const 16)
   )
  )
- (func $start (; 8 ;) (type $v)
+ (func $~lib/gc/gc.allocate (; 8 ;) (type $iii) (param $0 i32) (param $1 i32) (result i32)
+  (call $~lib/collector/itcm/__gc_allocate
+   (get_local $0)
+   (get_local $1)
+  )
+ )
+ (func $start (; 9 ;) (type $v)
   (set_global $~lib/allocator/arena/startOffset
    (i32.const 80)
   )
@@ -218,7 +224,7 @@
    (i32.const 0)
   )
   (set_global $std/gc/obj
-   (call $~lib/collector/itcm/gc.alloc
+   (call $~lib/gc/gc.allocate
     (i32.const 4)
     (i32.const 0)
    )
diff --git a/tests/compiler/std/gc.ts b/tests/compiler/std/gc.ts
index 4d0a5778..9c7ae1ed 100644
--- a/tests/compiler/std/gc.ts
+++ b/tests/compiler/std/gc.ts
@@ -1,5 +1,5 @@
 import "allocator/arena";
-import { gc } from "collector/itcm";
+import "collector/itcm";
 
 // a class to test with
 class MyObject {
@@ -8,7 +8,7 @@ class MyObject {
 function MyObject_visit(ref: usize): void { }
 
 // allocate a managed instance
-var obj = changetype<MyObject>(gc.alloc(offsetof<MyObject>(), MyObject_visit));
+var obj = changetype<MyObject>(gc.allocate(offsetof<MyObject>(), MyObject_visit));
 obj.a = 123;
 var head = changetype<usize>(obj) - 16;
 
diff --git a/tests/compiler/std/gc.untouched.wat b/tests/compiler/std/gc.untouched.wat
index 4b39ecc7..15b686ea 100644
--- a/tests/compiler/std/gc.untouched.wat
+++ b/tests/compiler/std/gc.untouched.wat
@@ -12,8 +12,6 @@
  (global $~lib/internal/allocator/MAX_SIZE_32 i32 (i32.const 1073741824))
  (global $~lib/allocator/arena/startOffset (mut i32) (i32.const 0))
  (global $~lib/allocator/arena/offset (mut i32) (i32.const 0))
- (global $NaN f64 (f64.const nan:0x8000000000000))
- (global $Infinity f64 (f64.const inf))
  (global $~lib/collector/itcm/State.INIT i32 (i32.const 0))
  (global $~lib/collector/itcm/State.IDLE i32 (i32.const 1))
  (global $~lib/collector/itcm/State.MARK i32 (i32.const 2))
@@ -209,7 +207,7 @@
    (get_local $1)
   )
  )
- (func $~lib/collector/itcm/gc.alloc (; 7 ;) (type $iii) (param $0 i32) (param $1 i32) (result i32)
+ (func $~lib/collector/itcm/__gc_allocate (; 7 ;) (type $iii) (param $0 i32) (param $1 i32) (result i32)
   (local $2 i32)
   (if
    (i32.eqz
@@ -225,8 +223,8 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 8)
-     (i32.const 214)
-     (i32.const 4)
+     (i32.const 216)
+     (i32.const 2)
     )
     (unreachable)
    )
@@ -250,12 +248,22 @@
    (get_global $~lib/collector/itcm/set1)
    (get_local $2)
   )
-  (i32.add
-   (get_local $2)
-   (get_global $~lib/collector/itcm/ManagedObject.SIZE)
+  (block $~lib/collector/itcm/objToRef|inlined.0 (result i32)
+   (i32.add
+    (get_local $2)
+    (get_global $~lib/collector/itcm/ManagedObject.SIZE)
+   )
   )
  )
- (func $start (; 8 ;) (type $v)
+ (func $~lib/gc/gc.allocate (; 8 ;) (type $iii) (param $0 i32) (param $1 i32) (result i32)
+  (return
+   (call $~lib/collector/itcm/__gc_allocate
+    (get_local $0)
+    (get_local $1)
+   )
+  )
+ )
+ (func $start (; 9 ;) (type $v)
   (set_global $~lib/allocator/arena/startOffset
    (i32.and
     (i32.add
@@ -275,7 +283,7 @@
    (get_global $~lib/collector/itcm/State.INIT)
   )
   (set_global $std/gc/obj
-   (call $~lib/collector/itcm/gc.alloc
+   (call $~lib/gc/gc.allocate
     (i32.const 4)
     (i32.const 0)
    )