Fix some TLSF inconsistencies (#1061)

Author: dcodeIO

std/assembly/array.ts

@@ -14,10 +14,10 @@ function ensureSize(array: usize, minSize: usize, alignLog2: u32): void {
     if (minSize > BLOCK_MAXSIZE >>> alignLog2) throw new RangeError(E_INVALIDLENGTH);
     let oldData = changetype<usize>(changetype<ArrayBufferView>(array).buffer);
     let newCapacity = minSize << alignLog2;
-    let newData = __realloc(oldData, newCapacity);
+    let newData = __realloc(oldData, newCapacity); // keeps RC
     memory.fill(newData + oldCapacity, 0, newCapacity - oldCapacity);
     if (newData !== oldData) { // oldData has been free'd
-      store<usize>(array, __retain(newData), offsetof<ArrayBufferView>("buffer"));
+      store<usize>(array, newData, offsetof<ArrayBufferView>("buffer"));
       store<usize>(array, newData, offsetof<ArrayBufferView>("dataStart"));
     }
     store<u32>(array, newCapacity, offsetof<ArrayBufferView>("byteLength"));

std/assembly/rt/tlsf.ts

@@ -486,7 +486,7 @@ export function maybeInitialize(): Root {
 var collectLock: bool = false;
 
 /** Allocates a block of the specified size. */
-export function allocateBlock(root: Root, size: usize): Block {
+export function allocateBlock(root: Root, size: usize, id: u32): Block {
   if (DEBUG) assert(!collectLock); // must not allocate while collecting
   var payloadSize = prepareSize(size);
   var block = searchBlock(root, payloadSize);
@@ -509,7 +509,7 @@ export function allocateBlock(root: Root, size: usize): Block {
   }
   if (DEBUG) assert((block.mmInfo & ~TAGS_MASK) >= payloadSize); // must fit
   block.gcInfo = 0; // RC=0
-  // block.rtId = 0; // set by the caller (__alloc)
+  block.rtId = id;
   block.rtSize = size;
   removeBlock(root, <Block>block);
   prepareBlock(root, <Block>block, payloadSize);
@@ -521,12 +521,6 @@ export function allocateBlock(root: Root, size: usize): Block {
 export function reallocateBlock(root: Root, block: Block, size: usize): Block {
   var payloadSize = prepareSize(size);
   var blockInfo = block.mmInfo;
-  if (DEBUG) {
-    assert(
-      !(blockInfo & FREE) &&           // must be used
-      !(block.gcInfo & ~REFCOUNT_MASK) // not buffered or != BLACK
-    );
-  }
 
   // possibly split and update runtime size if it still fits
   if (payloadSize <= (blockInfo & ~TAGS_MASK)) {
@@ -552,8 +546,8 @@ export function reallocateBlock(root: Root, block: Block, size: usize): Block {
   }
 
   // otherwise move the block
-  var newBlock = allocateBlock(root, size); // may invalidate cached blockInfo
-  newBlock.rtId = block.rtId;
+  var newBlock = allocateBlock(root, size, block.rtId); // may invalidate cached blockInfo
+  newBlock.gcInfo = block.gcInfo; // keep RC
   memory.copy(changetype<usize>(newBlock) + BLOCK_OVERHEAD, changetype<usize>(block) + BLOCK_OVERHEAD, size);
   if (changetype<usize>(block) >= __heap_base) freeBlock(root, block);
   return newBlock;
@@ -562,30 +556,40 @@ export function reallocateBlock(root: Root, block: Block, size: usize): Block {
 /** Frees a block. */
 export function freeBlock(root: Root, block: Block): void {
   var blockInfo = block.mmInfo;
-  assert(!(blockInfo & FREE)); // must be used (user might call through to this)
   block.mmInfo = blockInfo | FREE;
   insertBlock(root, block);
   if (isDefined(ASC_RTRACE)) onfree(block);
 }
 
+/** Checks that a used block is valid to be freed or reallocated. */
+function checkUsedBlock(ref: usize): Block {
+  var block = changetype<Block>(ref - BLOCK_OVERHEAD);
+  assert(
+    ref != 0 && !(ref & AL_MASK) &&  // must exist and be aligned
+    !(block.mmInfo & FREE) &&        // must be used
+    !(block.gcInfo & ~REFCOUNT_MASK) // not buffered or != BLACK
+  );
+  return block;
+}
+
 // @ts-ignore: decorator
 @global @unsafe
 export function __alloc(size: usize, id: u32): usize {
-  var block = allocateBlock(maybeInitialize(), size);
-  block.rtId = id;
-  return changetype<usize>(block) + BLOCK_OVERHEAD;
+  return changetype<usize>(
+    allocateBlock(maybeInitialize(), size, id)
+  ) + BLOCK_OVERHEAD;
 }
 
 // @ts-ignore: decorator
 @global @unsafe
 export function __realloc(ref: usize, size: usize): usize {
-  assert(ref != 0 && !(ref & AL_MASK)); // must exist and be aligned
-  return changetype<usize>(reallocateBlock(maybeInitialize(), changetype<Block>(ref - BLOCK_OVERHEAD), size)) + BLOCK_OVERHEAD;
+  return changetype<usize>(
+    reallocateBlock(maybeInitialize(), checkUsedBlock(ref), size)
+  ) + BLOCK_OVERHEAD;
 }
 
 // @ts-ignore: decorator
 @global @unsafe
 export function __free(ref: usize): void {
-  assert(ref != 0 && !(ref & AL_MASK)); // must exist and be aligned
-  freeBlock(maybeInitialize(), changetype<Block>(ref - BLOCK_OVERHEAD));
+  freeBlock(maybeInitialize(), checkUsedBlock(ref));
 }

tests/allocators/rt-full/optimized.wat

@@ -3,10 +3,11 @@
  (type $i32_i32_=>_none (func (param i32 i32)))
  (type $i32_i32_i32_=>_none (func (param i32 i32 i32)))
  (type $i32_=>_i32 (func (param i32) (result i32)))
- (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
  (type $none_=>_none (func))
+ (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (type $none_=>_i32 (func (result i32)))
+ (type $i32_i32_i32_=>_i32 (func (param i32 i32 i32) (result i32)))
  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
  (memory $0 1)
  (data (i32.const 16) "(\00\00\00\01\00\00\00\01\00\00\00(\00\00\00a\00l\00l\00o\00c\00a\00t\00i\00o\00n\00 \00t\00o\00o\00 \00l\00a\00r\00g\00e")
@@ -976,15 +977,15 @@
    i32.store
   end
  )
- (func $~lib/rt/tlsf/allocateBlock (; 15 ;) (param $0 i32) (param $1 i32) (result i32)
-  (local $2 i32)
+ (func $~lib/rt/tlsf/allocateBlock (; 15 ;) (param $0 i32) (param $1 i32) (param $2 i32) (result i32)
   (local $3 i32)
+  (local $4 i32)
   local.get $0
   local.get $1
   call $~lib/rt/tlsf/prepareSize
-  local.tee $3
+  local.tee $4
   call $~lib/rt/tlsf/searchBlock
-  local.tee $2
+  local.tee $3
   i32.eqz
   if
    i32.const 1
@@ -993,43 +994,43 @@
    i32.const 0
    global.set $~lib/rt/tlsf/collectLock
    local.get $0
-   local.get $3
+   local.get $4
    call $~lib/rt/tlsf/searchBlock
-   local.tee $2
+   local.tee $3
    i32.eqz
    if
     local.get $0
-    local.get $3
+    local.get $4
     call $~lib/rt/tlsf/growMemory
     local.get $0
-    local.get $3
+    local.get $4
     call $~lib/rt/tlsf/searchBlock
-    local.set $2
+    local.set $3
    end
   end
-  local.get $2
+  local.get $3
   i32.const 0
   i32.store offset=4
+  local.get $3
   local.get $2
+  i32.store offset=8
+  local.get $3
   local.get $1
   i32.store offset=12
   local.get $0
-  local.get $2
+  local.get $3
   call $~lib/rt/tlsf/removeBlock
   local.get $0
-  local.get $2
   local.get $3
+  local.get $4
   call $~lib/rt/tlsf/prepareBlock
-  local.get $2
+  local.get $3
  )
  (func $~lib/rt/tlsf/__alloc (; 16 ;) (param $0 i32) (param $1 i32) (result i32)
   call $~lib/rt/tlsf/maybeInitialize
   local.get $0
-  call $~lib/rt/tlsf/allocateBlock
-  local.tee $0
   local.get $1
-  i32.store offset=8
-  local.get $0
+  call $~lib/rt/tlsf/allocateBlock
   i32.const 16
   i32.add
  )