[Interpreter] Basic flow control.

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index 2a330ca87059de709f9d3ab3c91039b6738ee064..a84924463f325022663cb59ab7655d4ed857f7b9 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -118,7 +118,19 @@ void BytecodeGenerator::VisitEmptyStatement(EmptyStatement* stmt) {
 }
 
 
-void BytecodeGenerator::VisitIfStatement(IfStatement* stmt) { UNIMPLEMENTED(); }
+void BytecodeGenerator::VisitIfStatement(IfStatement* stmt) {
+  // TODO(oth): condition may need a ToBoolean cast - not if a
+  // sequence of test operations.

[rmcilroy, 2015/09/18 10:42:23]

Could you add the ToBoolean unconditionally for now (making the interpreter nop
this for now like the comparison ops is fine, but I'd like the bytecode
generated to be correct).

[oth, 2015/09/23 10:46:55]

Done.

+  // TODO(oth): spot easy cases if (true/1/false/0)?
+  BytecodeLabel else_start, else_end;
+  stmt->condition()->Accept(this);
+  builder().JumpIfFalse(&else_start);

[Benedikt Meurer, 2015/09/17 17:04:17]

Oh thank god, this is so much better to just materialize the stupid true/false
and compare against that in the if, than this micro optimization with the (most
often untagged) raw integer for the compare in fullcodegen. I think I'll try to
fix that in fullcodegen as well, so it is uniform. But this alone will avoid
some hairy tricks that we need to place to properly deopt to fullcodegen
currently.

+  Visit(stmt->then_statement());
+  builder().Jump(&else_end);
+  builder().Bind(&else_start);
+  Visit(stmt->else_statement());
+  builder().Bind(&else_end);
+}
 
 
 void BytecodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
@@ -452,7 +464,18 @@ void BytecodeGenerator::VisitBinaryOperation(BinaryOperation* binop) {
 
 
 void BytecodeGenerator::VisitCompareOperation(CompareOperation* expr) {
-  UNIMPLEMENTED();
+  Token::Value op = expr->op();
+  Expression* left = expr->left();
+  Expression* right = expr->right();
+
+  TemporaryRegisterScope temporary_register_scope(&builder_);
+  Register temporary = temporary_register_scope.NewRegister();
+
+  Visit(left);
+  builder().StoreAccumulatorInRegister(temporary);
+  Visit(right);
+  // TODO(oth): ast-graph-builder has language_mode() option for LT/LE/etc.

[rmcilroy, 2015/09/18 10:42:23]

Could you pass the language mode here and do UNIMPLEMENTED for everything except
SLOPPY in bytecode-array-builder (like the Load/StoreICs) - just to make sure we
don't miss this later and have subtle bugs.

[oth, 2015/09/23 10:46:55]

Done.

+  builder().CompareOperation(op, temporary);
 }