Add support for yield*

Change-Id: I5b054b59519ed825459a5b0b0a7cd2c6fc8a3797
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

4 files changed, 64 insertions, 8 deletions

diff --git a/src/qml/compiler/qv4bytecodehandler.cpp b/src/qml/compiler/qv4bytecodehandler.cpp
index 5b836c2e9c..65293becfd 100644
--- a/src/qml/compiler/qv4bytecodehandler.cpp
+++ b/src/qml/compiler/qv4bytecodehandler.cpp
@@ -240,6 +240,9 @@ std::vector<int> ByteCodeHandler::collectLabelsInBytecode(const char *code, uint
         COLLECTOR_BEGIN_INSTR(Yield)
         COLLECTOR_END_INSTR(Yield)
 
+        COLLECTOR_BEGIN_INSTR(YieldStar)
+        COLLECTOR_END_INSTR(YieldStar)
+
         COLLECTOR_BEGIN_INSTR(Resume)
         COLLECTOR_END_INSTR(Resume)
 
@@ -335,6 +338,9 @@ std::vector<int> ByteCodeHandler::collectLabelsInBytecode(const char *code, uint
         COLLECTOR_BEGIN_INSTR(IteratorNext)
         COLLECTOR_END_INSTR(IteratorNext)
 
+        COLLECTOR_BEGIN_INSTR(IteratorNextForYieldStar)
+        COLLECTOR_END_INSTR(IteratorNextForYieldStar)
+
         COLLECTOR_BEGIN_INSTR(IteratorClose)
         COLLECTOR_END_INSTR(IteratorClose)
 
diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 2415142df4..09f08e8bf2 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -2826,25 +2826,64 @@ bool Codegen::visit(FunctionDeclaration * ast)
 
 bool Codegen::visit(YieldExpression *ast)
 {
-    if (ast->isYieldStar) {
-        throwSyntaxError(ast->firstSourceLocation(), QLatin1String("yield* is not currently supported"));
-        return false;
-    }
     if (inFormalParameterList) {
         throwSyntaxError(ast->firstSourceLocation(), QLatin1String("yield is not allowed inside parameter lists"));
         return false;
     }
 
-
-    Reference result = ast->expression ? expression(ast->expression) : Reference::fromConst(this, Encode::undefined());
+    RegisterScope scope(this);
+    Reference expr = ast->expression ? expression(ast->expression) : Reference::fromConst(this, Encode::undefined());
     if (hasError)
         return false;
-    result.loadInAccumulator();
+
+    Reference acc = Reference::fromAccumulator(this);
+
+    if (ast->isYieldStar) {
+        Reference iterator = Reference::fromStackSlot(this);
+        Reference lhsValue = Reference::fromConst(this, Encode::undefined()).storeOnStack();
+
+        expr.loadInAccumulator();
+        Instruction::GetIterator getIterator;
+        getIterator.iterator = /*ForEachType::Of*/ 1;
+        bytecodeGenerator->addInstruction(getIterator);
+        iterator.storeConsumeAccumulator();
+        Instruction::LoadUndefined load;
+        bytecodeGenerator->addInstruction(load);
+
+        BytecodeGenerator::Label in = bytecodeGenerator->newLabel();
+        bytecodeGenerator->jump().link(in);
+
+        BytecodeGenerator::Label loop = bytecodeGenerator->label();
+
+        lhsValue.loadInAccumulator();
+        Instruction::YieldStar yield;
+        bytecodeGenerator->addInstruction(yield);
+
+        in.link();
+
+        Instruction::IteratorNextForYieldStar next;
+        next.object = lhsValue.stackSlot();
+        next.iterator = iterator.stackSlot();
+        bytecodeGenerator->addInstruction(next);
+
+        BytecodeGenerator::Jump done = bytecodeGenerator->jumpTrue();
+        bytecodeGenerator->jumpNotUndefined().link(loop);
+        lhsValue.loadInAccumulator();
+        emitReturn(acc);
+
+
+        done.link();
+
+        lhsValue.loadInAccumulator();
+        _expr.setResult(acc);
+        return false;
+    }
+
+    expr.loadInAccumulator();
     Instruction::Yield yield;
     bytecodeGenerator->addInstruction(yield);
     Instruction::Resume resume;
     BytecodeGenerator::Jump jump = bytecodeGenerator->addJumpInstruction(resume);
-    Reference acc = Reference::fromAccumulator(this);
     emitReturn(acc);
     jump.link();
     _expr.setResult(acc);
diff --git a/src/qml/compiler/qv4instr_moth.cpp b/src/qml/compiler/qv4instr_moth.cpp
index 00a1e8470b..a125f0ce28 100644
--- a/src/qml/compiler/qv4instr_moth.cpp
+++ b/src/qml/compiler/qv4instr_moth.cpp
@@ -349,6 +349,9 @@ void dumpBytecode(const char *code, int len, int nLocals, int nFormals, int /*st
         MOTH_BEGIN_INSTR(Yield)
         MOTH_END_INSTR(Yield)
 
+        MOTH_BEGIN_INSTR(YieldStar)
+        MOTH_END_INSTR(YieldStar)
+
         MOTH_BEGIN_INSTR(Resume)
             d << ABSOLUTE_OFFSET();
         MOTH_END_INSTR(Resume)
@@ -467,6 +470,10 @@ void dumpBytecode(const char *code, int len, int nLocals, int nFormals, int /*st
             d << dumpRegister(value, nFormals) << ", " << dumpRegister(done, nFormals);
         MOTH_END_INSTR(IteratorNext)
 
+        MOTH_BEGIN_INSTR(IteratorNextForYieldStar)
+            d << dumpRegister(iterator, nFormals) << ", " << dumpRegister(object, nFormals);
+        MOTH_END_INSTR(IteratorNextForYieldStar)
+
         MOTH_BEGIN_INSTR(IteratorClose)
             d << dumpRegister(done, nFormals);
         MOTH_END_INSTR(IteratorClose)
diff --git a/src/qml/compiler/qv4instr_moth_p.h b/src/qml/compiler/qv4instr_moth_p.h
index 34c80db0e8..f9bd3cdd4a 100644
--- a/src/qml/compiler/qv4instr_moth_p.h
+++ b/src/qml/compiler/qv4instr_moth_p.h
@@ -94,7 +94,9 @@ QT_BEGIN_NAMESPACE
 #define INSTR_LoadContextObjectProperty(op) INSTRUCTION(op, LoadContextObjectProperty, 3, propertyIndex, base, captureRequired)
 #define INSTR_LoadIdObject(op) INSTRUCTION(op, LoadIdObject, 2, index, base)
 #define INSTR_Yield(op) INSTRUCTION(op, Yield, 0)
+#define INSTR_YieldStar(op) INSTRUCTION(op, YieldStar, 0)
 #define INSTR_Resume(op) INSTRUCTION(op, Resume, 1, offset)
+#define INSTR_IteratorNextForYieldStar(op) INSTRUCTION(op, IteratorNextForYieldStar, 2, iterator, object)
 #define INSTR_StoreProperty(op) INSTRUCTION(op, StoreProperty, 2, name, base)
 #define INSTR_SetLookup(op) INSTRUCTION(op, SetLookup, 2, index, base)
 #define INSTR_LoadSuperProperty(op) INSTRUCTION(op, LoadSuperProperty, 1, property)
@@ -327,7 +329,9 @@ QT_BEGIN_NAMESPACE
     F(LoadQmlContext) \
     F(LoadQmlImportedScripts) \
     F(Yield) \
+    F(YieldStar) \
     F(Resume) \
+    F(IteratorNextForYieldStar) \
     F(CreateClass) \
     F(LoadSuperConstructor) \
     F(PushScriptContext) \