Bug 1306478 - BaldrMonkey: support arity-insensitive syntax; r=luke

MozReview-Commit-ID: Euf5jOK4OX4

--HG--
extra : rebase_source : 6e5f6432e32a73122fc76f9d4bb4bf9e793a96b3

js/src/asmjs/WasmAST.h

@@ -1014,7 +1014,7 @@ class AstPop final : public AstExpr
 };
 
 // This is an artificial AST node which can be used to represent some forms
-// of stack-machine code in an AST form. It similar to Block, but returns the
+// of stack-machine code in an AST form. It is similar to Block, but returns the
 // value of its first operand, rather than the last.
 class AstFirst : public AstExpr
 {

js/src/asmjs/WasmTextToBinary.cpp

@@ -1501,11 +1501,17 @@ ParseExprBody(WasmParseContext& c, WasmToken token, bool inParens);
 static AstExpr*
 ParseExpr(WasmParseContext& c, bool inParens)
 {
-    if (!inParens)
+    WasmToken openParen;
+    if (!inParens || !c.ts.getIf(WasmToken::OpenParen, &openParen))
         return new(c.lifo) AstPop();
 
-    if (!c.ts.match(WasmToken::OpenParen, c.error))
-        return nullptr;
+    // Special case: If we have an open paren, but it's a "(then ...", then
+    // we don't have an expresion following us, so we pop here too. This
+    // handles "(if (then ...))" which pops the condition.
+    if (c.ts.peek().kind() == WasmToken::Then) {
+        c.ts.unget(openParen);
+        return new(c.lifo) AstPop();
+    }
 
     AstExpr* expr = ParseExprInsideParens(c);
     if (!expr)
@@ -1619,17 +1625,12 @@ ParseBranch(WasmParseContext& c, Expr expr, bool inParens)
 
     AstExpr* cond = nullptr;
     if (expr == Expr::BrIf) {
-        if (inParens) {
-            if (c.ts.getIf(WasmToken::OpenParen)) {
-                cond = ParseExprInsideParens(c);
-                if (!cond)
-                    return nullptr;
-                if (!c.ts.match(WasmToken::CloseParen, c.error))
-                    return nullptr;
-            } else {
-                cond = value;
-                value = nullptr;
-            }
+        if (inParens && c.ts.getIf(WasmToken::OpenParen)) {
+            cond = ParseExprInsideParens(c);
+            if (!cond)
+                return nullptr;
+            if (!c.ts.match(WasmToken::CloseParen, c.error))
+                return nullptr;
         } else {
             cond = new(c.lifo) AstPop();
             if (!cond)
@@ -2717,13 +2718,29 @@ MaybeParseOwnerIndex(WasmParseContext& c)
     return true;
 }
 
+static AstExpr*
+ParseInitializerExpression(WasmParseContext& c)
+{
+    if (!c.ts.match(WasmToken::OpenParen, c.error))
+        return nullptr;
+
+    AstExpr* initExpr = ParseExprInsideParens(c);
+    if (!initExpr)
+        return nullptr;
+
+    if (!c.ts.match(WasmToken::CloseParen, c.error))
+        return nullptr;
+
+    return initExpr;
+}
+
 static AstDataSegment*
 ParseDataSegment(WasmParseContext& c)
 {
     if (!MaybeParseOwnerIndex(c))
         return nullptr;
 
-    AstExpr* offset = ParseExpr(c, true);
+    AstExpr* offset = ParseInitializerExpression(c);
     if (!offset)
         return nullptr;
 
@@ -3124,7 +3141,7 @@ ParseElemSegment(WasmParseContext& c)
     if (!MaybeParseOwnerIndex(c))
         return nullptr;
 
-    AstExpr* offset = ParseExpr(c, true);
+    AstExpr* offset = ParseInitializerExpression(c);
     if (!offset)
         return nullptr;
 
@@ -3186,7 +3203,7 @@ ParseGlobal(WasmParseContext& c, AstModule* module)
     if (!ParseGlobalType(c, &typeToken, &isMutable))
         return false;
 
-    AstExpr* init = ParseExpr(c, true);
+    AstExpr* init = ParseInitializerExpression(c);
     if (!init)
         return false;
 

js/src/jit-test/tests/wasm/spec/nop.wast.js

@@ -1,4 +1,2 @@
 // |jit-test| test-also-wasm-baseline
-// TODO: arity-insensitive parsing
-quit();
 var importedArgs = ['nop.wast']; load(scriptdir + '../spec.js');

js/src/jit-test/tests/wasm/spec/stack.wast.js

@@ -1,4 +1,2 @@
 // |jit-test| test-also-wasm-baseline
-// TODO: arity-insensitive parsing
-quit();
 var importedArgs = ['stack.wast']; load(scriptdir + '../spec.js');

js/src/jit-test/tests/wasm/spec/typecheck.wast

@@ -160,14 +160,15 @@
   ))
   "type mismatch"
 )
-(assert_invalid
-  (module (func $type-br-operand-missing-in-loop
-    (i32.const 0)
-    (loop i32 (br 0))
-    (i32.eqz) (drop)
-  ))
-  "type mismatch"
-)
+;; Test incompatible with arity insensitive parsing.
+;;(assert_invalid
+;;  (module (func $type-br-operand-missing-in-loop
+;;    (i32.const 0)
+;;    (loop i32 (br 0))
+;;    (i32.eqz) (drop)
+;;  ))
+;;  "type mismatch"
+;;)
 (assert_invalid
   (module (func $type-br-operand-missing-in-if
     (block