[js] Implement nqp::throwpayloadlexcaller.

Author: pmurias

src/vm/js/Compiler.nqp

@@ -51,6 +51,8 @@ class QAST::CompilerJS does DWIMYNameMangling does SerializeOnce {
 
         has %!statevars;
 
+        has $!pass_on_exceptions;
+
         method new($qast, $outer) {
             my $obj := nqp::create(self);
             $obj.BUILD($qast, $outer);
@@ -74,6 +76,15 @@ class QAST::CompilerJS does DWIMYNameMangling does SerializeOnce {
             %!lexicalref_types := nqp::hash();
             @!var_setup := nqp::list();
             %!statevars := nqp::hash();
+            $!pass_on_exceptions := 0;
+        }
+
+        method pass_on_exceptions() {
+            $!pass_on_exceptions;
+        }
+
+        method use_passing_on_of_exceptions() {
+            $!pass_on_exceptions := 1;
         }
 
         method add_var_setup($setup) {
@@ -1024,6 +1035,21 @@ class QAST::CompilerJS does DWIMYNameMangling does SerializeOnce {
 
                 my $first_time_marker := $*BLOCK.maybe_first_time_marker;
 
+                my $pass_exceptions_start := '';
+                my $pass_exceptions_end := '';
+
+                if $*BLOCK.pass_on_exceptions {
+                    $pass_exceptions_start := "try \{\n";
+                    $pass_exceptions_end :=
+                        ~ "\} catch (e) \{\n"
+                        ~ "if (e instanceof nqp.PassExceptionToCaller) \{\n"
+                        ~ "throw e.exception;\n"
+                        ~ "\} else \{"
+                        ~ "throw e;\n"
+                        ~ "\}"
+                        ~ "\}";
+                }
+
                 my @function := [
                     "function({$sig.expr}) \{\n" ,
                     $first_time_marker ?? "$first_time_marker = 1;\n" !! '',
@@ -1034,8 +1060,10 @@ class QAST::CompilerJS does DWIMYNameMangling does SerializeOnce {
                     $sig,
                     self.clone_inners($*BLOCK),
                     self.capture_inners($*BLOCK),
+                    $pass_exceptions_start,
                     $stmts,
                     "return {$stmts.expr};\n",
+                    $pass_exceptions_end,
                     "\}"
                 ];
                 %*BLOCKS_DONE{$node.cuid} := Chunk.void("(", |@function, ")");

src/vm/js/Operations.nqp

@@ -1298,7 +1298,8 @@ class QAST::OperationsJS {
 
         my $protected := $comp.as_js(:want($T_OBJ), $node[0]);
 
-        if $*RETURN.is_used {
+        # HACK - we assume how return is used on the nqp backend and avoid handling some exceptions
+        if $*HLL ne 'nqp' || $*RETURN.is_used {
             my $handle_result := $comp.as_js(:want($T_OBJ), $node[2]);
 
             Chunk.new($T_OBJ, $result, [
@@ -1321,11 +1322,16 @@ class QAST::OperationsJS {
 
     });
 
+    my sub is_CONTROL_RETURN($category) {
+        $category ~~ QAST::IVal && $category.value == nqp::const::CONTROL_RETURN
+            || $category ~~ QAST::Op && $category.op eq 'const' && $category.name eq 'CONTROL_RETURN';
+    }
+
     add_op('throwpayloadlex', :!inlinable, sub ($comp, $node, :$want, :$cps) {
         my $category := $node[0];
         my $payload := $comp.as_js(:want($T_OBJ), $node[1]);
 
-        unless $category ~~ QAST::IVal && $category.value == nqp::const::CONTROL_RETURN {
+        unless is_CONTROL_RETURN($category) {
             return $comp.NYI("throwpayloadlex with something else then a CONTROL_RETURN literal");
         }
 
@@ -1345,6 +1351,22 @@ class QAST::OperationsJS {
         ]);
     });
 
+    add_op('throwpayloadlexcaller', :!inlinable, sub ($comp, $node, :$want, :$cps) {
+        my $category := $node[0];
+        my $payload := $comp.as_js(:want($T_OBJ), $node[1]);
+
+        unless is_CONTROL_RETURN($category) {
+            return $comp.NYI("throwpayloadlexcaller with something else then a CONTROL_RETURN literal");
+        }
+
+        $*BLOCK.use_passing_on_of_exceptions();
+
+        Chunk.new($T_VOID, "", [
+            $payload,
+            "throw new nqp.PassExceptionToCaller(new nqp.ControlReturn({$payload.expr}));\n"
+        ]);
+    });
+
     add_simple_op('lastexpayload', $T_OBJ, [], sub () { '$$e.payload' }, :!inlinable, :sideffects);
 
 

src/vm/js/nqp-runtime/runtime.js

@@ -355,14 +355,19 @@ exports.wrapException = function(e) {
 function ControlReturn(payload) {
   this.payload = payload;
 }
+exports.ControlReturn = ControlReturn;
+
+function PassExceptionToCaller(exception) {
+  this.exception = exception;
+}
+exports.PassExceptionToCaller = PassExceptionToCaller;
 
 exports.setCodeRefHLL = function(codeRefs, hllName) {
   for (var i = 0; i < codeRefs.length; i++) {
     codeRefs[i].hll = hll.hllConfigs[hllName];
   }
 };
 
-exports.ControlReturn = ControlReturn;
 
 /* TODO - make monkey patching builtin things optional */