Add PostAssemblyScript pass (#2407)

Adds the AssemblyScript-specific passes post-assemblyscript
and post-assemblyscript-finalize, eliminating redundant ARC-style
retain/release patterns conservatively emitted by the compiler.

4 files changed, 699 insertions, 0 deletions

diff --git a/test/passes/post-assemblyscript-finalize.txt b/test/passes/post-assemblyscript-finalize.txt
new file mode 100644
index 000000000..46f69acdf
--- /dev/null
+++ b/test/passes/post-assemblyscript-finalize.txt
@@ -0,0 +1,40 @@
+(module
+ (type $FUNCSIG$ii (func (param i32) (result i32)))
+ (type $FUNCSIG$vi (func (param i32)))
+ (type $FUNCSIG$iii (func (param i32 i32) (result i32)))
+ (type $FUNCSIG$v (func))
+ (import "rt" "retain" (func $~lib/rt/pure/__retain (param i32) (result i32)))
+ (import "rt" "release" (func $~lib/rt/pure/__release (param i32)))
+ (import "rt" "alloc" (func $~lib/rt/tlsf/__alloc (param i32 i32) (result i32)))
+ (func $eliminates.unnecessaryAllocation (; 3 ;) (type $FUNCSIG$v)
+  (nop)
+ )
+ (func $eliminates.unnecessaryPair (; 4 ;) (type $FUNCSIG$vi) (param $0 i32)
+  (drop
+   (local.get $0)
+  )
+ )
+ (func $eliminates.unnecessaryStaticPair (; 5 ;) (type $FUNCSIG$v)
+  (nop)
+ )
+ (func $eliminates.unnecessaryStaticRetain (; 6 ;) (type $FUNCSIG$v)
+  (drop
+   (i32.const 272)
+  )
+ )
+ (func $eliminates.unnecessaryStaticRelease (; 7 ;) (type $FUNCSIG$v)
+  (nop)
+ )
+ (func $keeps.dynamicRetain (; 8 ;) (type $FUNCSIG$vi) (param $0 i32)
+  (local.set $0
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+ )
+ (func $keeps.dynamicRelease (; 9 ;) (type $FUNCSIG$vi) (param $0 i32)
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+)
diff --git a/test/passes/post-assemblyscript-finalize.wast b/test/passes/post-assemblyscript-finalize.wast
new file mode 100644
index 000000000..6de35b471
--- /dev/null
+++ b/test/passes/post-assemblyscript-finalize.wast
@@ -0,0 +1,54 @@
+;; FinalizeARC part of assemblyscript/tests/compiler/rc/optimize
+(module
+ (import "rt" "retain" (func $~lib/rt/pure/__retain (param i32) (result i32)))
+ (import "rt" "release" (func $~lib/rt/pure/__release (param i32)))
+ (import "rt" "alloc" (func $~lib/rt/tlsf/__alloc (param i32) (param i32) (result i32)))
+ (func $eliminates.unnecessaryAllocation
+  (call $~lib/rt/pure/__release
+   (call $~lib/rt/pure/__retain
+    (call $~lib/rt/tlsf/__alloc
+     (i32.const 1)
+     (i32.const 0)
+    )
+   )
+  )
+ )
+ (func $eliminates.unnecessaryPair (param $0 i32)
+  (call $~lib/rt/pure/__release
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+ )
+ (func $eliminates.unnecessaryStaticPair
+  (call $~lib/rt/pure/__release
+   (call $~lib/rt/pure/__retain
+    (i32.const 272)
+   )
+  )
+ )
+ (func $eliminates.unnecessaryStaticRetain
+  (drop
+   (call $~lib/rt/pure/__retain
+    (i32.const 272)
+   )
+  )
+ )
+ (func $eliminates.unnecessaryStaticRelease
+  (call $~lib/rt/pure/__release
+   (i32.const 272)
+  )
+ )
+ (func $keeps.dynamicRetain (param $0 i32)
+  (local.set $0
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+ )
+ (func $keeps.dynamicRelease (param $0 i32)
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+)
diff --git a/test/passes/post-assemblyscript.txt b/test/passes/post-assemblyscript.txt
new file mode 100644
index 000000000..b81301cd4
--- /dev/null
+++ b/test/passes/post-assemblyscript.txt
@@ -0,0 +1,263 @@
+(module
+ (type $FUNCSIG$ii (func (param i32) (result i32)))
+ (type $FUNCSIG$vi (func (param i32)))
+ (type $FUNCSIG$vii (func (param i32 i32)))
+ (type $FUNCSIG$viii (func (param i32 i32 i32)))
+ (type $FUNCSIG$i (func (result i32)))
+ (type $FUNCSIG$iii (func (param i32 i32) (result i32)))
+ (import "rt" "retain" (func $~lib/rt/pure/__retain (param i32) (result i32)))
+ (import "rt" "release" (func $~lib/rt/pure/__release (param i32)))
+ (import "rc" "getRetainedRef" (func $getRetainedRef (result i32)))
+ (func $eliminates.linearArgument (; 3 ;) (type $FUNCSIG$vi) (param $0 i32)
+  (local.set $0
+   (local.get $0)
+  )
+  (nop)
+ )
+ (func $eliminates.linearLocal (; 4 ;) (type $FUNCSIG$vi) (param $0 i32)
+  (local $1 i32)
+  (local.set $1
+   (local.get $0)
+  )
+  (nop)
+ )
+ (func $eliminates.linearChain (; 5 ;) (type $FUNCSIG$vi) (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local.set $1
+   (local.get $0)
+  )
+  (local.set $2
+   (local.get $1)
+  )
+  (local.set $3
+   (local.get $2)
+  )
+  (nop)
+  (nop)
+  (nop)
+ )
+ (func $eliminates.balancedReleases (; 6 ;) (type $FUNCSIG$vii) (param $0 i32) (param $cond i32)
+  (local $2 i32)
+  (local.set $2
+   (local.get $0)
+  )
+  (if
+   (local.get $cond)
+   (nop)
+   (nop)
+  )
+ )
+ (func $eliminates.partialReleases (; 7 ;) (type $FUNCSIG$vii) (param $0 i32) (param $cond i32)
+  (local $2 i32)
+  (local.set $2
+   (local.get $0)
+  )
+  (if
+   (local.get $cond)
+   (nop)
+  )
+ )
+ (func $eliminates.balancedRetains (; 8 ;) (type $FUNCSIG$viii) (param $0 i32) (param $cond1 i32) (param $cond2 i32)
+  (local $3 i32)
+  (if
+   (local.get $cond1)
+   (if
+    (local.get $cond2)
+    (local.set $3
+     (local.get $0)
+    )
+    (local.set $3
+     (local.get $0)
+    )
+   )
+   (local.set $3
+    (local.get $0)
+   )
+  )
+  (nop)
+ )
+ (func $eliminates.balancedInsideLoop (; 9 ;) (type $FUNCSIG$vii) (param $0 i32) (param $cond i32)
+  (local $flat i32)
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (local.set $0
+     (local.get $0)
+    )
+    (nop)
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+ )
+ (func $eliminates.balancedOutsideLoop (; 10 ;) (type $FUNCSIG$vii) (param $0 i32) (param $cond i32)
+  (local $flat i32)
+  (local.set $0
+   (local.get $0)
+  )
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+  (nop)
+ )
+ (func $eliminates.balancedInsideOutsideLoop (; 11 ;) (type $FUNCSIG$vii) (param $0 i32) (param $cond i32)
+  (local $flat i32)
+  (local.set $0
+   (local.get $0)
+  )
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (nop)
+    (local.set $0
+     (local.get $0)
+    )
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+  (nop)
+ )
+ (func $eliminates.balancedInsideOutsideLoopWithBranch (; 12 ;) (type $FUNCSIG$viii) (param $0 i32) (param $cond1 i32) (param $cond2 i32)
+  (local $flat i32)
+  (local.set $0
+   (local.get $0)
+  )
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond1)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (if
+     (local.get $cond2)
+     (block $block
+      (nop)
+      (return)
+     )
+    )
+    (nop)
+    (local.set $0
+     (local.get $0)
+    )
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+  (nop)
+ )
+ (func $eliminates.replace (; 13 ;) (type $FUNCSIG$vii) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local.set $0
+   (local.get $0)
+  )
+  (local.set $1
+   (local.get $1)
+  )
+  (local.set $2
+   (local.get $1)
+  )
+  (local.set $3
+   (local.get $0)
+  )
+  (if
+   (i32.ne
+    (local.get $2)
+    (local.get $3)
+   )
+   (local.set $2
+    (local.get $2)
+   )
+   (nop)
+  )
+  (local.set $0
+   (local.get $2)
+  )
+  (nop)
+  (nop)
+ )
+ (func $eliminates.replaceAlreadyRetained (; 14 ;) (type $FUNCSIG$ii) (param $0 i32) (result i32)
+  (local $1 i32)
+  (block $block
+   (local.set $0
+    (local.get $0)
+   )
+   (local.set $1
+    (call $getRetainedRef)
+   )
+   (nop)
+   (local.set $0
+    (local.get $1)
+   )
+   (return
+    (local.get $0)
+   )
+  )
+ )
+ (func $keeps.partialRetains (; 15 ;) (type $FUNCSIG$vii) (param $0 i32) (param $cond i32)
+  (if
+   (local.get $cond)
+   (local.set $0
+    (call $~lib/rt/pure/__retain
+     (local.get $0)
+    )
+   )
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+ (func $keeps.reachesReturn (; 16 ;) (type $FUNCSIG$iii) (param $0 i32) (param $cond i32) (result i32)
+  (block $block
+   (local.set $0
+    (call $~lib/rt/pure/__retain
+     (local.get $0)
+    )
+   )
+   (if
+    (local.get $cond)
+    (return
+     (local.get $0)
+    )
+   )
+   (call $~lib/rt/pure/__release
+    (local.get $0)
+   )
+   (return
+    (i32.const 0)
+   )
+  )
+ )
+)
diff --git a/test/passes/post-assemblyscript.wast b/test/passes/post-assemblyscript.wast
new file mode 100644
index 000000000..c79bfe1d9
--- /dev/null
+++ b/test/passes/post-assemblyscript.wast
@@ -0,0 +1,342 @@
+;; OptimizeARC part of assemblyscript/tests/compiler/rc/optimize
+;; with flattening applied manually
+(module
+ (import "rt" "retain" (func $~lib/rt/pure/__retain (param i32) (result i32)))
+ (import "rt" "release" (func $~lib/rt/pure/__release (param i32)))
+ (func $eliminates.linearArgument (param $0 i32)
+  (local.set $0
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+ (func $eliminates.linearLocal (param $0 i32)
+  (local $1 i32)
+  (local.set $1
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $1)
+  )
+ )
+ (func $eliminates.linearChain (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local.set $1
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (local.set $2
+   (call $~lib/rt/pure/__retain
+    (local.get $1)
+   )
+  )
+  (local.set $3
+   (call $~lib/rt/pure/__retain
+    (local.get $2)
+   )
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $3)
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $2)
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $1)
+  )
+ )
+  (func $eliminates.balancedReleases (param $0 i32) (param $cond i32)
+  (local $2 i32)
+  (local.set $2
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (if
+   (local.get $cond)
+   (call $~lib/rt/pure/__release
+    (local.get $2)
+   )
+   (call $~lib/rt/pure/__release
+    (local.get $2)
+   )
+  )
+ )
+ (func $eliminates.partialReleases (param $0 i32) (param $cond i32)
+  ;; technically invalid but assumed to be never emitted
+  (local $2 i32)
+  (local.set $2
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (if
+   (local.get $cond)
+   (call $~lib/rt/pure/__release
+    (local.get $2)
+   )
+  )
+ )
+ (func $eliminates.balancedRetains (param $0 i32) (param $cond1 i32) (param $cond2 i32)
+  (local $3 i32)
+  (if
+   (local.get $cond1)
+   (if
+    (local.get $cond2)
+    (local.set $3
+     (call $~lib/rt/pure/__retain
+      (local.get $0)
+     )
+    )
+    (local.set $3
+     (call $~lib/rt/pure/__retain
+      (local.get $0)
+     )
+    )
+   )
+   (local.set $3
+    (call $~lib/rt/pure/__retain
+     (local.get $0)
+    )
+   )
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $3)
+  )
+ )
+ (func $eliminates.balancedInsideLoop (param $0 i32) (param $cond i32)
+  (local $flat i32)
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (local.set $0
+     (call $~lib/rt/pure/__retain
+      (local.get $0)
+     )
+    )
+    (call $~lib/rt/pure/__release
+     (local.get $0)
+    )
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+ )
+ (func $eliminates.balancedOutsideLoop (param $0 i32) (param $cond i32)
+  (local $flat i32)
+  (local.set $0
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+ (func $eliminates.balancedInsideOutsideLoop (param $0 i32) (param $cond i32)
+  (local $flat i32)
+  (local.set $0
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (call $~lib/rt/pure/__release
+     (local.get $0)
+    )
+    (local.set $0
+     (call $~lib/rt/pure/__retain
+      (local.get $0)
+     )
+    )
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+ (func $eliminates.balancedInsideOutsideLoopWithBranch (param $0 i32) (param $cond1 i32) (param $cond2 i32)
+  (local $flat i32)
+  (local.set $0
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (block $break|0
+   (loop $continue|0
+    (local.set $flat
+     (i32.eqz
+      (local.get $cond1)
+     )
+    )
+    (br_if $break|0
+     (local.get $flat)
+    )
+    (if
+     (local.get $cond2)
+     (block
+      (call $~lib/rt/pure/__release
+       (local.get $0)
+      )
+      (return)
+     )
+    )
+    (call $~lib/rt/pure/__release
+     (local.get $0)
+    )
+    (local.set $0
+     (call $~lib/rt/pure/__retain
+      (local.get $0)
+     )
+    )
+    (br $continue|0)
+   )
+   (unreachable)
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+ (func $eliminates.replace (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local.set $0
+   (call $~lib/rt/pure/__retain
+    (local.get $0)
+   )
+  )
+  (local.set $1
+   (call $~lib/rt/pure/__retain
+    (local.get $1)
+   )
+  )
+  ;; flat
+  (local.set $2
+   (local.get $1)
+  )
+  (local.set $3
+   (local.get $0)
+  )
+  ;; /flat
+  (if
+   (i32.ne
+    (local.get $2) ;; flat (local.tee $2 (local.get $1))
+    (local.get $3) ;; flat (local.tee $3 (local.get $0))
+   )
+   (local.set $2
+    (call $~lib/rt/pure/__retain
+     (local.get $2)
+    )
+   )
+   (call $~lib/rt/pure/__release
+    (local.get $3)
+   )
+  )
+  (local.set $0
+   (local.get $2)
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $1)
+  )
+ )
+ (import "rc" "getRetainedRef" (func $getRetainedRef (result i32)))
+ (func $eliminates.replaceAlreadyRetained (param $0 i32) (result i32)
+  (local $1 i32)
+  (block
+   (local.set $0
+    (call $~lib/rt/pure/__retain
+     (local.get $0)
+    )
+   )
+   (local.set $1
+    (call $getRetainedRef)
+   )
+   (call $~lib/rt/pure/__release
+    (local.get $0)
+   )
+   (local.set $0
+    (local.get $1)
+   )
+   (return
+    (local.get $0)
+   )
+  )
+ )
+ (func $keeps.partialRetains (param $0 i32) (param $cond i32)
+  (if
+   (local.get $cond)
+   (local.set $0
+    (call $~lib/rt/pure/__retain
+     (local.get $0)
+    )
+   )
+  )
+  (call $~lib/rt/pure/__release
+   (local.get $0)
+  )
+ )
+ (func $keeps.reachesReturn (param $0 i32) (param $cond i32) (result i32)
+  (block
+   (local.set $0
+    (call $~lib/rt/pure/__retain
+     (local.get $0)
+    )
+   )
+   (if
+    (local.get $cond)
+    (return
+     (local.get $0)
+    )
+   )
+   (call $~lib/rt/pure/__release
+    (local.get $0)
+   )
+   (return
+    (i32.const 0)
+   )
+  )
+ )
+)