Tailcall (#918)

This doesn't do any of the real work yet, it just adds the
ReturnCall/ReturnCallIndirect Expr and Opcode types, and the
"--enable-tail-call" flag.

Still TODO:

* Parse the opcodes in binary-reader.cc
* Validate the opcodes in validator.cc and type-checker.cc
* Implement the opcodes in interp.cc
* Write standard wabt tests, and enable the spec proposal tests too

1 files changed, 12 insertions, 0 deletions

diff --git a/src/validator.cc b/src/validator.cc
index 27bf2422..fc255b43 100644
--- a/src/validator.cc
+++ b/src/validator.cc
@@ -70,6 +70,8 @@ class Validator : public ExprVisitor::Delegate {
   Result OnMemorySizeExpr(MemorySizeExpr*) override;
   Result OnNopExpr(NopExpr*) override;
   Result OnReturnExpr(ReturnExpr*) override;
+  Result OnReturnCallExpr(ReturnCallExpr*) override;
+  Result OnReturnCallIndirectExpr(ReturnCallIndirectExpr*) override;
   Result OnSelectExpr(SelectExpr*) override;
   Result OnSetGlobalExpr(SetGlobalExpr*) override;
   Result OnSetLocalExpr(SetLocalExpr*) override;
@@ -708,6 +710,16 @@ Result Validator::OnReturnExpr(ReturnExpr* expr) {
   return Result::Ok;
 }
 
+Result Validator::OnReturnCallExpr(ReturnCallExpr* expr) {
+  // TODO(binji): implement.
+  return Result::Error;
+}
+
+Result Validator::OnReturnCallIndirectExpr(ReturnCallIndirectExpr* expr) {
+  // TODO(binji): implement.
+  return Result::Error;
+}
+
 Result Validator::OnSelectExpr(SelectExpr* expr) {
   expr_loc_ = &expr->loc;
   typechecker_.OnSelect();