Return address handling. Not happy with the design, but it (sorta) works.

src/alloy/backend/ivm/ivm_function.cc

@@ -34,7 +34,7 @@ void IVMFunction::Setup(TranslationContext& ctx) {
   intcodes_ = (IntCode*)ctx.intcode_arena->CloneContents();
 }
 
-int IVMFunction::CallImpl(ThreadState* thread_state) {
+int IVMFunction::CallImpl(ThreadState* thread_state, uint64_t return_address) {
   // Setup register file on stack.
   size_t register_file_size = register_count_ * sizeof(Register);
   Register* register_file = (Register*)alloca(register_file_size);
@@ -46,7 +46,8 @@ int IVMFunction::CallImpl(ThreadState* thread_state) {
   ics.did_carry = 0;
   ics.access_callbacks = thread_state->runtime()->access_callbacks();
   ics.thread_state = thread_state;
-  ics.return_address = 0xBEBEBEBE;
+  ics.return_address = return_address;
+  ics.call_return_address = 0;
 
   // TODO(benvanik): DID_CARRY -- need HIR to set a OPCODE_FLAG_SET_CARRY
   //                 or something so the fns can set an ics flag.

src/alloy/backend/ivm/ivm_function.h

@@ -29,7 +29,8 @@ public:
   void Setup(TranslationContext& ctx);
 
 protected:
-  virtual int CallImpl(runtime::ThreadState* thread_state);
+  virtual int CallImpl(runtime::ThreadState* thread_state,
+                       uint64_t return_address);
 
 private:
 

src/alloy/backend/ivm/ivm_intcode.cc

@@ -523,10 +523,13 @@ int Translate_TRAP_TRUE(TranslationContext& ctx, Instr* i) {
 
 uint32_t IntCode_CALL_XX(IntCodeState& ics, const IntCode* i, uint32_t reg) {
   FunctionInfo* symbol_info = (FunctionInfo*)ics.rf[reg].u64;
-  Function* fn;
+  Function* fn = NULL;
   ics.thread_state->runtime()->ResolveFunction(symbol_info->address(), &fn);
+  XEASSERTNOTNULL(fn);
   // TODO(benvanik): proper tail call support, somehow.
-  fn->Call(ics.thread_state);
+  uint64_t return_address =
+      (i->flags & CALL_TAIL) ? ics.return_address : ics.call_return_address;
+  fn->Call(ics.thread_state, return_address);
   if (i->flags & CALL_TAIL) {
     return IA_RETURN;
   }
@@ -589,16 +592,21 @@ int Translate_CALL_TRUE(TranslationContext& ctx, Instr* i) {
 }
 
 uint32_t IntCode_CALL_INDIRECT_XX(IntCodeState& ics, const IntCode* i, uint32_t reg) {
+  uint64_t target = ics.rf[reg].u64;
+
   // Check if return address - if so, return.
-  /*if (ics.rf[reg].u64 == ics.return_address) {
+  if (target == ics.return_address) {
     return IA_RETURN;
-  }*/
+  }
 
   // Real call.
-  Function* fn;
-  ics.thread_state->runtime()->ResolveFunction(ics.rf[reg].u64, &fn);
+  Function* fn = NULL;
+  ics.thread_state->runtime()->ResolveFunction(target, &fn);
+  XEASSERTNOTNULL(fn);
   // TODO(benvanik): proper tail call support, somehow.
-  fn->Call(ics.thread_state);
+  uint64_t return_address =
+      (i->flags & CALL_TAIL) ? ics.return_address : ics.call_return_address;
+  fn->Call(ics.thread_state, return_address);
   if (i->flags & CALL_TAIL) {
     return IA_RETURN;
   }
@@ -667,6 +675,14 @@ int Translate_RETURN(TranslationContext& ctx, Instr* i) {
   return DispatchToC(ctx, i, IntCode_RETURN);
 }
 
+uint32_t IntCode_SET_RETURN_ADDRESS(IntCodeState& ics, const IntCode* i) {
+  ics.call_return_address = ics.rf[i->src1_reg].u32;
+  return IA_NEXT;
+}
+int Translate_SET_RETURN_ADDRESS(TranslationContext& ctx, Instr* i) {
+  return DispatchToC(ctx, i, IntCode_SET_RETURN_ADDRESS);
+}
+
 uint32_t IntCode_BRANCH_XX(IntCodeState& ics, const IntCode* i, uint32_t reg) {
   return ics.rf[reg].u32;
 }
@@ -1167,6 +1183,7 @@ uint32_t IntCode_LOAD_I32(IntCodeState& ics, const IntCode* i) {
   if (DYNAMIC_REGISTER_ACCESS_CHECK(address)) {
     return IntCode_LOAD_REGISTER_I32_DYNAMIC(ics, i);
   }
+  DFLUSH();
   DPRINT("%d (%X) = load.i32 %.8X\n",
          *((int32_t*)(ics.membase + address)),
          *((uint32_t*)(ics.membase + address)),
@@ -2827,6 +2844,7 @@ static const TranslateFn dispatch_table[] = {
   Translate_CALL_INDIRECT,
   Translate_CALL_INDIRECT_TRUE,
   Translate_RETURN,
+  Translate_SET_RETURN_ADDRESS,
 
   Translate_BRANCH,
   Translate_BRANCH_IF,

src/alloy/backend/ivm/ivm_intcode.h

@@ -47,6 +47,7 @@ typedef struct {
   runtime::RegisterAccessCallbacks* access_callbacks;
   runtime::ThreadState* thread_state;
   uint64_t      return_address;
+  uint64_t      call_return_address;
 } IntCodeState;