add lambda skeleton

goalc/compiler/Lambda.h

@@ -0,0 +1,10 @@
+
+
+#ifndef JAK_LAMBDA_H
+#define JAK_LAMBDA_H
+
+struct Lambda {
+  std::string debug_name;
+};
+
+#endif  // JAK_LAMBDA_H

goalc/compiler/Val.cpp

@@ -3,20 +3,39 @@
 /*!
  * Fallback to_gpr if a more optimized one is not provided.
  */
-RegVal* Val::to_gpr(FunctionEnv* fe) const {
+const RegVal* Val::to_gpr(FunctionEnv* fe) const {
   (void)fe;
-  throw std::runtime_error("Val::to_gpr NYI");
+  throw std::runtime_error("Val::to_gpr NYI");  // todo
 }
 
 /*!
  * Fallback to_xmm if a more optimized one is not provided.
  */
-RegVal* Val::to_xmm(FunctionEnv* fe) const {
+const RegVal* Val::to_xmm(FunctionEnv* fe) const {
   (void)fe;
-  throw std::runtime_error("Val::to_xmm NYI");
+  throw std::runtime_error("Val::to_xmm NYI");  // todo
 }
 
-RegVal* None::to_reg(FunctionEnv* fe) const {
+
+const RegVal* RegVal::to_reg(FunctionEnv* fe) const {
   (void)fe;
-  throw std::runtime_error("Cannot put None into a register.");
+  return this;
+}
+
+const RegVal * RegVal::to_gpr(FunctionEnv* fe) const {
+  (void)fe;
+  if(m_ireg.kind == emitter::RegKind::GPR) {
+    return this;
+  } else {
+    throw std::runtime_error("RegVal::to_gpr NYI"); // todo
+  }
+}
+
+const RegVal * RegVal::to_xmm(FunctionEnv* fe) const {
+  (void)fe;
+  if(m_ireg.kind == emitter::RegKind::XMM) {
+    return this;
+  } else {
+    throw std::runtime_error("RegVal::to_xmm NYI"); // todo
+  }
 }

goalc/compiler/Val.h

@@ -12,6 +12,7 @@
 #include "third-party/fmt/core.h"
 #include "common/type_system/TypeSystem.h"
 #include "goalc/regalloc/IRegister.h"
+#include "Lambda.h"
 
 class RegVal;
 class FunctionEnv;
@@ -30,9 +31,11 @@ class Val {
   }
 
   virtual std::string print() const = 0;
-  virtual RegVal* to_reg(FunctionEnv* fe) const = 0;
+  virtual const RegVal* to_reg(FunctionEnv* fe) const {
-  virtual RegVal* to_gpr(FunctionEnv* fe) const;
+    throw std::runtime_error("to_reg called on invalid Val: " + print());
-  virtual RegVal* to_xmm(FunctionEnv* fe) const;
+  }
+  virtual const RegVal* to_gpr(FunctionEnv* fe) const;
+  virtual const RegVal* to_xmm(FunctionEnv* fe) const;
 
   const TypeSpec& type() const { return m_ts; }
 
@@ -47,7 +50,6 @@ class None : public Val {
   explicit None(TypeSpec _ts) : Val(std::move(_ts)) {}
   explicit None(const TypeSystem& _ts) : Val(_ts.make_typespec("none")) {}
   std::string print() const override { return "none"; }
-  RegVal* to_reg(FunctionEnv* fe) const override;
 };
 
 /*!
@@ -59,16 +61,42 @@ class RegVal : public Val {
   bool is_register() const override { return true; }
   IRegister ireg() const override { return m_ireg; }
   std::string print() const override { return m_ireg.to_string(); };
-  RegVal* to_reg(FunctionEnv* fe) const override;
+  const RegVal* to_reg(FunctionEnv* fe) const override;
-  RegVal* to_gpr(FunctionEnv* fe) const override;
+  const RegVal* to_gpr(FunctionEnv* fe) const override;
-  RegVal* to_xmm(FunctionEnv* fe) const override;
+  const RegVal* to_xmm(FunctionEnv* fe) const override;
 
  protected:
   IRegister m_ireg;
 };
 
-// Symbol
+/*!
-// Lambda
+ * A Val representing a symbol. This is confusing but it's not actually the value of the symbol,
+ * but instead the symbol itself.
+ */
+class SymbolVal : public Val {
+ public:
+  SymbolVal(std::string name, TypeSpec ts) : Val(std::move(ts)), m_name(std::move(name)) {}
+  const std::string& name() { return m_name; }
+  std::string print() const override { return "<" + m_name + ">"; }
+
+ protected:
+  std::string m_name;
+};
+
+/*!
+ * A Val representing a GOAL lambda. It can be a "real" x86-64 function, in which case the
+ * FunctionEnv is set. Otherwise, just contains a Lambda.
+ */
+class LambdaVal : public Val {
+ public:
+  LambdaVal(TypeSpec ts, Lambda lam) : Val(ts), m_lam(lam) {}
+  std::string print() const override { return "lambda-" + m_lam.debug_name; }
+
+ protected:
+  Lambda m_lam;
+  FunctionEnv* fe = nullptr;
+};
+
 // Static
 // MemOffConstant
 // MemOffVar