Add in support to compile Methods and MethodCallExpr

There is more work to be done here with adjustments to the self argument
such as borrows and mutability checking.

Method resolution is basic, for now there is code to scan for all possible
matches but traits are not supported at the moment so this resolves quite
simply for now.

Fixes #191 #112

6 files changed, 321 insertions, 179 deletions

diff --git a/gcc/rust/backend/cscope.h b/gcc/rust/backend/cscope.h
deleted file mode 100644
index 3ba837c..0000000
--- a/gcc/rust/backend/cscope.h
+++ /dev/null
@@ -1,160 +0,0 @@
-// Copyright (C) 2020 Free Software Foundation, Inc.
-
-// This file is part of GCC.
-
-// GCC is free software; you can redistribute it and/or modify it under
-// the terms of the GNU General Public License as published by the Free
-// Software Foundation; either version 3, or (at your option) any later
-// version.
-
-// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
-// WARRANTY; without even the implied warranty of MERCHANTABILITY or
-// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-// for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with GCC; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-#pragma once
-
-#include "rust-system.h"
-#include "rust-backend.h"
-#include "scope.h"
-
-namespace Rust {
-namespace Compile {
-
-class Scope
-{
-public:
-  Scope (Backend *backend) : backend (backend) {}
-
-  ~Scope () {}
-
-  void Push ()
-  {
-    fndecls.Push ();
-    vars.Push ();
-    types.Push ();
-    structDecls.Push ();
-  }
-
-  void Pop ()
-  {
-    fndecls.Pop ();
-    vars.Pop ();
-    types.Pop ();
-    structDecls.Pop ();
-  }
-
-  void PushCurrentFunction (std::string name, Bfunction *fn, Btype *retType,
-			    Bvariable *retDecl)
-  {
-    fns.push_back (fn);
-    fnRetType.push_back (retType);
-    fnRetDecl.push_back (retDecl);
-  }
-
-  Bfunction *PopCurrentFunction ()
-  {
-    auto ret = fns.back ();
-    fns.pop_back ();
-    fnRetType.pop_back ();
-    fnRetDecl.pop_back ();
-    return ret;
-  }
-
-  Bfunction *GetCurrentFndecl () { return fns.back (); }
-
-  Btype *GetCurrentFnRetType () { return fnRetType.back (); }
-
-  Bvariable *GetCurrentFnRetDecl () { return fnRetDecl.back (); }
-
-  Btype *GetFnRetType (Bfunction *fn)
-  {
-    auto it = fnRetTypeMapping.find (fn);
-    if (it == fnRetTypeMapping.end ())
-      {
-	return NULL;
-      }
-    return it->second;
-  }
-
-  void PushBlock (Bblock *block)
-  {
-    blocks.push_back (block);
-    std::vector<Bstatement *> empty;
-    context.push_back (empty);
-  }
-
-  Bblock *PopBlock ()
-  {
-    auto ret = blocks.back ();
-    blocks.pop_back ();
-
-    auto stmts = context.back ();
-    context.pop_back ();
-
-    backend->block_add_statements (ret, stmts);
-
-    return ret;
-  }
-
-  Bblock *CurBlock () { return blocks.back (); }
-
-  void AddStatement (Bstatement *stmt) { context.back ().push_back (stmt); }
-
-  void InsertStructDecl (std::string name, AST::StructStruct *decl)
-  {
-    structDecls.Insert (name, decl);
-  }
-
-  bool LookupStructDecl (std::string name, AST::StructStruct **decl)
-  {
-    return structDecls.Lookup (name, decl);
-  }
-
-  void InsertFunction (std::string name, Bfunction *fn, Btype *retType)
-  {
-    fndecls.Insert (name, fn);
-    fnRetTypeMapping[fn] = retType;
-  }
-
-  bool LookupFunction (std::string name, Bfunction **fn)
-  {
-    return fndecls.Lookup (name, fn);
-  }
-
-  void InsertType (std::string name, Btype *type) { types.Insert (name, type); }
-
-  bool LookupType (std::string name, Btype **type)
-  {
-    return types.Lookup (name, type);
-  }
-
-  void InsertVar (std::string name, Bvariable *var) { vars.Insert (name, var); }
-
-  bool LookupVar (std::string name, Bvariable **var)
-  {
-    return vars.Lookup (name, var);
-  }
-
-private:
-  Backend *backend;
-
-  ::std::vector<Bfunction *> fns;
-  ::std::vector<Bblock *> blocks;
-  ::std::vector< ::std::vector<Bstatement *> > context;
-  ::std::vector< ::Btype *> fnRetType;
-  ::std::vector< ::Bvariable *> fnRetDecl;
-  ::std::map<Bfunction *, Btype *> fnRetTypeMapping;
-
-  Analysis::Scope<Bfunction *> fndecls;
-  Analysis::Scope<Bvariable *> vars;
-  Analysis::Scope<Btype *> types;
-  Analysis::Scope<AST::StructStruct *> structDecls;
-};
-
-} // namespace Compile
-} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-expr.h b/gcc/rust/backend/rust-compile-expr.h
index fad5ce0..b823d29 100644
--- a/gcc/rust/backend/rust-compile-expr.h
+++ b/gcc/rust/backend/rust-compile-expr.h
@@ -99,6 +99,8 @@ public:
 
   void visit (HIR::CallExpr &expr);
 
+  void visit (HIR::MethodCallExpr &expr);
+
   void visit (HIR::IdentifierExpr &expr)
   {
     // need to look up the reference for this identifier
diff --git a/gcc/rust/backend/rust-compile-fnparam.h b/gcc/rust/backend/rust-compile-fnparam.h
index cf6e6f7..1ea0c9f 100644
--- a/gcc/rust/backend/rust-compile-fnparam.h
+++ b/gcc/rust/backend/rust-compile-fnparam.h
@@ -61,6 +61,22 @@ private:
   ::Bvariable *translated;
 };
 
+class CompileSelfParam : public HIRCompileBase
+{
+public:
+  static Bvariable *compile (Context *ctx, Bfunction *fndecl,
+			     HIR::SelfParam &self, Btype *decl_type,
+			     Location locus)
+  {
+    if (!self.get_is_mut ())
+      decl_type = ctx->get_backend ()->immutable_type (decl_type);
+
+    return ctx->get_backend ()->parameter_variable (fndecl, "self", decl_type,
+						    false /* address_taken */,
+						    locus);
+  }
+};
+
 } // namespace Compile
 } // namespace Rust
 
diff --git a/gcc/rust/backend/rust-compile-implitem.h b/gcc/rust/backend/rust-compile-implitem.h
index 8286a5c..6d180c8 100644
--- a/gcc/rust/backend/rust-compile-implitem.h
+++ b/gcc/rust/backend/rust-compile-implitem.h
@@ -32,10 +32,10 @@ namespace Compile {
 class CompileInherentImplItem : public HIRCompileBase
 {
 public:
-  static void Compile (HIR::Type *base, HIR::InherentImplItem *item,
+  static void Compile (TyTy::TyBase *self, HIR::InherentImplItem *item,
 		       Context *ctx, bool compile_fns)
   {
-    CompileInherentImplItem compiler (base, ctx, compile_fns);
+    CompileInherentImplItem compiler (self, ctx, compile_fns);
     item->accept_vis (compiler);
   }
 
@@ -50,7 +50,7 @@ public:
     ::Btype *type = TyTyResolveCompile::compile (ctx, resolved_type);
     Bexpression *value = CompileExpr::Compile (constant.get_expr (), ctx);
 
-    std::string ident = base->as_string () + "::" + constant.get_identifier ();
+    std::string ident = self->as_string () + "::" + constant.get_identifier ();
     Bexpression *const_expr = ctx->get_backend ()->named_constant_expression (
       type, constant.get_identifier (), value, constant.get_locus ());
 
@@ -78,7 +78,8 @@ public:
     if (!ctx->get_tyctx ()->lookup_type (function.get_mappings ().get_hirid (),
 					 &fntype_tyty))
       {
-	rust_fatal_error (function.locus, "failed to lookup function type");
+	rust_fatal_error (function.get_locus (),
+			  "failed to lookup function type");
 	return;
       }
 
@@ -93,23 +94,15 @@ public:
     ::Btype *compiled_fn_type = TyTyResolveCompile::compile (ctx, fntype);
 
     unsigned int flags = 0;
-    bool is_main_fn = function.function_name.compare ("main") == 0;
-
     std::string fn_identifier
-      = base->as_string () + "::" + function.function_name;
+      = self->as_string () + "::" + function.function_name;
 
     // if its the main fn or pub visibility mark its as DECL_PUBLIC
     // please see https://github.com/Rust-GCC/gccrs/pull/137
-    if (is_main_fn || function.has_visibility ())
+    if (function.has_visibility ())
       flags |= Backend::function_is_visible;
 
     std::string asm_name = fn_identifier;
-    if (!is_main_fn)
-      {
-	// FIXME need name mangling
-	asm_name = "__" + function.function_name;
-      }
-
     Bfunction *fndecl
       = ctx->get_backend ()->function (compiled_fn_type, fn_identifier,
 				       asm_name, flags, function.get_locus ());
@@ -229,12 +222,217 @@ public:
     ctx->push_function (fndecl);
   }
 
+  void visit (HIR::Method &method)
+  {
+    if (!compile_fns)
+      return;
+
+    // items can be forward compiled which means we may not need to invoke this
+    // code
+    Bfunction *lookup = nullptr;
+    if (ctx->lookup_function_decl (method.get_mappings ().get_hirid (),
+				   &lookup))
+      {
+	// has this been added to the list then it must be finished
+	if (ctx->function_completed (lookup))
+	  return;
+      }
+
+    TyTy::TyBase *fntype_tyty;
+    if (!ctx->get_tyctx ()->lookup_type (method.get_mappings ().get_hirid (),
+					 &fntype_tyty))
+      {
+	rust_fatal_error (method.get_locus (),
+			  "failed to lookup function type");
+	return;
+      }
+
+    if (fntype_tyty->get_kind () != TyTy::TypeKind::FNDEF)
+      {
+	rust_error_at (method.get_locus (), "invalid TyTy for function item");
+	return;
+      }
+
+    TyTy::FnType *fntype = (TyTy::FnType *) fntype_tyty;
+    // convert to the actual function type
+    ::Btype *compiled_fn_type = TyTyResolveCompile::compile (ctx, fntype);
+
+    unsigned int flags = 0;
+    std::string fn_identifier
+      = self->as_string () + "::" + method.get_method_name ();
+
+    // if its the main fn or pub visibility mark its as DECL_PUBLIC
+    // please see https://github.com/Rust-GCC/gccrs/pull/137
+    if (method.has_visibility ())
+      flags |= Backend::function_is_visible;
+
+    std::string asm_name = fn_identifier;
+    Bfunction *fndecl
+      = ctx->get_backend ()->function (compiled_fn_type, fn_identifier,
+				       asm_name, flags, method.get_locus ());
+    ctx->insert_function_decl (method.get_mappings ().get_hirid (), fndecl);
+
+    // setup the params
+    TyTy::TyBase *tyret = fntype->return_type ();
+    std::vector<Bvariable *> param_vars;
+
+    // insert self
+    TyTy::TyBase *self_tyty_lookup = nullptr;
+    if (!ctx->get_tyctx ()->lookup_type (
+	  method.get_self_param ().get_mappings ().get_hirid (),
+	  &self_tyty_lookup))
+      {
+	rust_error_at (method.get_self_param ().get_locus (),
+		       "failed to lookup self param type");
+	return;
+      }
+
+    Btype *self_type = TyTyResolveCompile::compile (ctx, self_tyty_lookup);
+    if (self_type == nullptr)
+      {
+	rust_error_at (method.get_self_param ().get_locus (),
+		       "failed to compile self param type");
+	return;
+      }
+
+    Bvariable *compiled_self_param
+      = CompileSelfParam::compile (ctx, fndecl, method.get_self_param (),
+				   self_type,
+				   method.get_self_param ().get_locus ());
+    if (compiled_self_param == nullptr)
+      {
+	rust_error_at (method.get_self_param ().get_locus (),
+		       "failed to compile self param variable");
+	return;
+      }
+
+    param_vars.push_back (compiled_self_param);
+    ctx->insert_var_decl (method.get_self_param ().get_mappings ().get_hirid (),
+			  compiled_self_param);
+
+    // offset from + 1 for the TyTy::FnType being used
+    size_t i = 1;
+    for (auto referenced_param : method.get_function_params ())
+      {
+	auto tyty_param = fntype->param_at (i);
+	auto param_tyty = tyty_param.second;
+
+	auto compiled_param_type
+	  = TyTyResolveCompile::compile (ctx, param_tyty);
+	if (compiled_param_type == nullptr)
+	  {
+	    rust_error_at (referenced_param.get_locus (),
+			   "failed to compile parameter type");
+	    return;
+	  }
+
+	Location param_locus
+	  = ctx->get_mappings ()->lookup_location (param_tyty->get_ref ());
+	Bvariable *compiled_param_var
+	  = CompileFnParam::compile (ctx, fndecl, &referenced_param,
+				     compiled_param_type, param_locus);
+	if (compiled_param_var == nullptr)
+	  {
+	    rust_error_at (param_locus, "failed to compile parameter variable");
+	    return;
+	  }
+
+	param_vars.push_back (compiled_param_var);
+
+	ctx->insert_var_decl (referenced_param.get_mappings ().get_hirid (),
+			      compiled_param_var);
+	i++;
+      }
+
+    if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+      {
+	rust_fatal_error (method.get_locus (),
+			  "failed to setup parameter variables");
+	return;
+      }
+
+    // lookup locals
+    auto block_expr = method.get_function_body ().get ();
+    auto body_mappings = block_expr->get_mappings ();
+
+    Resolver::Rib *rib = nullptr;
+    if (!ctx->get_resolver ()->find_name_rib (body_mappings.get_nodeid (),
+					      &rib))
+      {
+	rust_fatal_error (method.get_locus (),
+			  "failed to setup locals per block");
+	return;
+      }
+
+    std::vector<Bvariable *> locals;
+    rib->iterate_decls ([&] (NodeId n, Location) mutable -> bool {
+      Resolver::Definition d;
+      bool ok = ctx->get_resolver ()->lookup_definition (n, &d);
+      rust_assert (ok);
+
+      HIR::Stmt *decl = nullptr;
+      ok = ctx->get_mappings ()->resolve_nodeid_to_stmt (d.parent, &decl);
+      rust_assert (ok);
+
+      Bvariable *compiled = CompileVarDecl::compile (fndecl, decl, ctx);
+      locals.push_back (compiled);
+
+      return true;
+    });
+
+    bool toplevel_item
+      = method.get_mappings ().get_local_defid () != UNKNOWN_LOCAL_DEFID;
+    Bblock *enclosing_scope
+      = toplevel_item ? NULL : ctx->peek_enclosing_scope ();
+
+    HIR::BlockExpr *function_body = method.get_function_body ().get ();
+    Location start_location = function_body->get_locus ();
+    Location end_location = function_body->get_closing_locus ();
+
+    Bblock *code_block
+      = ctx->get_backend ()->block (fndecl, enclosing_scope, locals,
+				    start_location, end_location);
+    ctx->push_block (code_block);
+
+    Bvariable *return_address = nullptr;
+    if (method.has_function_return_type ())
+      {
+	Btype *return_type = TyTyResolveCompile::compile (ctx, tyret);
+
+	bool address_is_taken = false;
+	Bstatement *ret_var_stmt = nullptr;
+
+	return_address = ctx->get_backend ()->temporary_variable (
+	  fndecl, code_block, return_type, NULL, address_is_taken,
+	  method.get_locus (), &ret_var_stmt);
+
+	ctx->add_statement (ret_var_stmt);
+      }
+
+    ctx->push_fn (fndecl, return_address);
+
+    compile_function_body (fndecl, method.get_function_body (),
+			   method.has_function_return_type ());
+
+    ctx->pop_block ();
+    auto body = ctx->get_backend ()->block_statement (code_block);
+    if (!ctx->get_backend ()->function_set_body (fndecl, body))
+      {
+	rust_error_at (method.get_locus (), "failed to set body to function");
+	return;
+      }
+
+    ctx->pop_fn ();
+
+    ctx->push_function (fndecl);
+  }
+
 private:
-  CompileInherentImplItem (HIR::Type *base, Context *ctx, bool compile_fns)
-    : HIRCompileBase (ctx), base (base), compile_fns (compile_fns)
+  CompileInherentImplItem (TyTy::TyBase *self, Context *ctx, bool compile_fns)
+    : HIRCompileBase (ctx), self (self), compile_fns (compile_fns)
   {}
 
-  HIR::Type *base;
+  TyTy::TyBase *self;
   bool compile_fns;
 };
 
diff --git a/gcc/rust/backend/rust-compile-item.h b/gcc/rust/backend/rust-compile-item.h
index b08c49e..7f93af9f 100644
--- a/gcc/rust/backend/rust-compile-item.h
+++ b/gcc/rust/backend/rust-compile-item.h
@@ -282,9 +282,18 @@ public:
 
   void visit (HIR::InherentImpl &impl_block)
   {
+    TyTy::TyBase *self_lookup = nullptr;
+    if (!ctx->get_tyctx ()->lookup_type (
+	  impl_block.get_type ()->get_mappings ().get_hirid (), &self_lookup))
+      {
+	rust_error_at (impl_block.get_locus (),
+		       "failed to resolve type of impl");
+	return;
+      }
+
     for (auto &impl_item : impl_block.get_impl_items ())
-      CompileInherentImplItem::Compile (impl_block.get_type ().get (),
-					impl_item.get (), ctx, compile_fns);
+      CompileInherentImplItem::Compile (self_lookup, impl_item.get (), ctx,
+					compile_fns);
   }
 
 private:
diff --git a/gcc/rust/backend/rust-compile.cc b/gcc/rust/backend/rust-compile.cc
index f72cf4c..0b83c72 100644
--- a/gcc/rust/backend/rust-compile.cc
+++ b/gcc/rust/backend/rust-compile.cc
@@ -95,6 +95,83 @@ CompileExpr::visit (HIR::CallExpr &expr)
     }
 }
 
+void
+CompileExpr::visit (HIR::MethodCallExpr &expr)
+{
+  // lookup the resolved name
+  NodeId resolved_node_id = UNKNOWN_NODEID;
+  if (!ctx->get_resolver ()->lookup_resolved_name (
+	expr.get_mappings ().get_nodeid (), &resolved_node_id))
+    {
+      rust_error_at (expr.get_locus (), "failed to lookup resolved MethodCall");
+      return;
+    }
+
+  // reverse lookup
+  HirId ref;
+  if (!ctx->get_mappings ()->lookup_node_to_hir (
+	expr.get_mappings ().get_crate_num (), resolved_node_id, &ref))
+    {
+      rust_fatal_error (expr.get_locus (), "reverse lookup failure");
+      return;
+    }
+
+  // lookup compiled functions
+  Bfunction *fn = nullptr;
+  if (!ctx->lookup_function_decl (ref, &fn))
+    {
+      // this might fail because its a forward decl so we can attempt to
+      // resolve it now
+      HIR::InherentImplItem *resolved_item
+	= ctx->get_mappings ()->lookup_hir_implitem (
+	  expr.get_mappings ().get_crate_num (), ref);
+      if (resolved_item == nullptr)
+	{
+	  rust_error_at (expr.get_locus (), "failed to lookup forward decl");
+	  return;
+	}
+
+      TyTy::TyBase *self_type = nullptr;
+      if (!ctx->get_tyctx ()->lookup_type (
+	    expr.get_receiver ()->get_mappings ().get_hirid (), &self_type))
+	{
+	  rust_error_at (expr.get_locus (),
+			 "failed to resolve type for self param");
+	  return;
+	}
+
+      CompileInherentImplItem::Compile (self_type, resolved_item, ctx, true);
+      if (!ctx->lookup_function_decl (ref, &fn))
+	{
+	  rust_error_at (expr.get_locus (), "forward decl was not compiled");
+	  return;
+	}
+    }
+
+  Bexpression *fn_expr
+    = ctx->get_backend ()->function_code_expression (fn, expr.get_locus ());
+
+  std::vector<Bexpression *> args;
+
+  // method receiver
+  Bexpression *self = CompileExpr::Compile (expr.get_receiver ().get (), ctx);
+  rust_assert (self != nullptr);
+  args.push_back (self);
+
+  // normal args
+  expr.iterate_params ([&] (HIR::Expr *p) mutable -> bool {
+    Bexpression *compiled_expr = CompileExpr::Compile (p, ctx);
+    rust_assert (compiled_expr != nullptr);
+    args.push_back (compiled_expr);
+    return true;
+  });
+
+  auto fncontext = ctx->peek_fn ();
+  translated
+    = ctx->get_backend ()->call_expression (fncontext.fndecl, fn_expr, args,
+					    nullptr, expr.get_locus ());
+}
+
 // rust-compile-block.h
 
 void