Block can take inputs (#57)

* a case shows that block can have inputs

* now block instructions can accept input

* tweak

* more tests and fix If's evaluation

* resolve some TODO and more consistent naming

* block can only use the values that it declared to use

* fix tidy issues

* truncate redundant values when exiting a block

* a problematic WIP implementation

* leave usage of type use syntax as placeholder

* try loop poly

* still enable type use syntax, only ignore their index

* tweak test case to align new exporting requirement

* update test case

* remove some line wrappings

---------

Co-authored-by: ahuoguo <ahuoguo@gmail.com>
Co-authored-by: Guannan Wei <wei220@purdue.edu>

Author: 3 people

benchmarks/wasm/block.wat

@@ -0,0 +1,70 @@
+(module
+  (func $test_block (param i32 i32 i32) (result i32)
+    local.get 0
+    local.get 1
+    local.get 2
+    block (param i32 i32 i32) (result i32 i32)
+      i32.add
+    end
+    i32.add
+  )
+  (func $real_main (result i32)
+    i32.const 1
+    i32.const 3
+    i32.const 5
+    call $test_block
+  )
+  ;; Sum from [0, 10]
+  (func $test_loop_input (result i32)
+    (local i32)
+    i32.const 10
+    local.set 0
+    i32.const 0
+    loop (param i32) (result i32)
+      local.get 0
+      i32.add
+      local.get 0
+      i32.const 1
+      i32.sub
+      local.set 0
+      i32.const 0
+      local.get 0
+      i32.ne
+      br_if 0
+    end
+  )
+  (func $test_if_input (result i32)
+    i32.const 10
+    i32.const 5
+    i32.const 1
+    if (param i32 i32) (result i32 i32)
+      i32.const 10
+      i32.add
+      else
+    end
+    i32.add
+  )
+  (func $test_poly_br (result i32)
+    i32.const -30
+    i32.const 0 ;; unused
+    i32.const 0 ;; unused
+    i32.const 0 ;; unused
+    block (param i32 i32 i32) (result i32 i32)
+      i32.const 0 ;; truncated
+      i32.const 10000 ;; truncated
+      i32.const 10
+      i32.const 20
+      br 0
+      i32.add
+    end
+    i32.add
+    i32.add ;; add value -30 and 30
+    ;; i32.add
+    ;; We can't use i32.add instruction here, because the overflowed value has been truncted
+    ;; when block exited.
+  )
+  (export "real_main" (func 1))
+  (export "test_loop_input" (func 2))
+  (export "test_if_input" (func 3))
+  (export "test_poly_br" (func 4))
+)

benchmarks/wasm/loop_poly.wat

@@ -0,0 +1,20 @@
+(module
+  (type (;0;) (func))
+  (type (;1;) (func (param i32) (result i32)))
+  (func $test_poly_loop (;0;) (type 0)
+    i32.const 42
+    i32.const 0
+    block (param i32 i32) (result i32 i32)
+      loop (type 1) (param i32) (result i32) ;; label = @1
+        i32.const 1
+        i32.const 2
+        br 1 (;@1;)
+      end
+    end
+    ;; this is not a valid wasm program due to the mismatch of stack shape,
+    ;; we only do this for testing purposes.
+    ;; i32.add
+    ;; drop
+  )
+  (start 0)
+)

grammar/WatParser.g4

@@ -204,11 +204,13 @@ blockInstr
   ;
 
 blockType
-  : LPAR RESULT valType RPAR
+  : (LPAR RESULT valType RPAR)?
+  | typeUse funcType
+  | funcType // abbreviation
   ;
 
 block
-  : blockType? instrList
+  : blockType instrList
   ;
 
 foldedInstr
@@ -221,7 +223,7 @@ expr
   | BLOCK bindVar? block
   | LOOP bindVar? block
   // | IF bindVar? ifBlock
-  | IF bindVar? blockType? foldedInstr* LPAR THEN instrList (LPAR ELSE instrList RPAR)?
+  | IF bindVar? blockType foldedInstr* LPAR THEN instrList (LPAR ELSE instrList RPAR)?
   ;
 
 callExprType