Merge #1492

1492: Redo coercion site code r=philberty a=philberty

This gets rid of the old visitor method and brings us much closer to the
Rustc rules which from the algo mentioned in the comment's do the checks
in a very specific order which we need to match.


Co-authored-by: Philip Herron <philip.herron@embecosm.com>

3 files changed, 47 insertions, 10 deletions

diff --git a/gcc/rust/backend/rust-compile-base.h b/gcc/rust/backend/rust-compile-base.h
index 5a0ac8f..4c20933 100644
--- a/gcc/rust/backend/rust-compile-base.h
+++ b/gcc/rust/backend/rust-compile-base.h
@@ -48,7 +48,6 @@ protected:
 		       Location rvalue_locus);
 
   tree coerce_to_dyn_object (tree compiled_ref, const TyTy::BaseType *actual,
-			     const TyTy::BaseType *expected,
 			     const TyTy::DynamicObjectType *ty, Location locus);
 
   tree compute_address_for_trait_item (
@@ -78,6 +77,12 @@ protected:
   tree resolve_unsized_adjustment (Resolver::Adjustment &adjustment,
 				   tree expression, Location locus);
 
+  tree resolve_unsized_slice_adjustment (Resolver::Adjustment &adjustment,
+					 tree expression, Location locus);
+
+  tree resolve_unsized_dyn_adjustment (Resolver::Adjustment &adjustment,
+				       tree expression, Location locus);
+
   static void setup_fndecl (tree fndecl, bool is_main_entry_point,
 			    bool is_generic_fn, HIR::Visibility &visibility,
 			    const HIR::FunctionQualifiers &qualifiers,
diff --git a/gcc/rust/backend/rust-compile-expr.cc b/gcc/rust/backend/rust-compile-expr.cc
index 9a8b779..412ca09 100644
--- a/gcc/rust/backend/rust-compile-expr.cc
+++ b/gcc/rust/backend/rust-compile-expr.cc
@@ -2514,6 +2514,27 @@ tree
 HIRCompileBase::resolve_unsized_adjustment (Resolver::Adjustment &adjustment,
 					    tree expression, Location locus)
 {
+  bool expect_slice
+    = adjustment.get_expected ()->get_kind () == TyTy::TypeKind::SLICE;
+  bool expect_dyn
+    = adjustment.get_expected ()->get_kind () == TyTy::TypeKind::DYNAMIC;
+
+  // assumes this is an array
+  tree expr_type = TREE_TYPE (expression);
+  if (expect_slice)
+    {
+      rust_assert (TREE_CODE (expr_type) == ARRAY_TYPE);
+      return resolve_unsized_slice_adjustment (adjustment, expression, locus);
+    }
+
+  rust_assert (expect_dyn);
+  return resolve_unsized_dyn_adjustment (adjustment, expression, locus);
+}
+
+tree
+HIRCompileBase::resolve_unsized_slice_adjustment (
+  Resolver::Adjustment &adjustment, tree expression, Location locus)
+{
   // assumes this is an array
   tree expr_type = TREE_TYPE (expression);
   rust_assert (TREE_CODE (expr_type) == ARRAY_TYPE);
@@ -2542,6 +2563,25 @@ HIRCompileBase::resolve_unsized_adjustment (Resolver::Adjustment &adjustment,
 						      {data, size}, -1, locus);
 }
 
+tree
+HIRCompileBase::resolve_unsized_dyn_adjustment (
+  Resolver::Adjustment &adjustment, tree expression, Location locus)
+{
+  tree rvalue = expression;
+  Location rvalue_locus = locus;
+
+  const TyTy::BaseType *actual = adjustment.get_actual ();
+  const TyTy::BaseType *expected = adjustment.get_expected ();
+
+  const TyTy::DynamicObjectType *dyn
+    = static_cast<const TyTy::DynamicObjectType *> (expected);
+
+  rust_debug ("resolve_unsized_dyn_adjustment actual={%s} dyn={%s}",
+	      actual->debug_str ().c_str (), dyn->debug_str ().c_str ());
+
+  return coerce_to_dyn_object (rvalue, actual, dyn, rvalue_locus);
+}
+
 void
 CompileExpr::visit (HIR::RangeFromToExpr &expr)
 {
diff --git a/gcc/rust/backend/rust-compile.cc b/gcc/rust/backend/rust-compile.cc
index 6913144..0ccb98d 100644
--- a/gcc/rust/backend/rust-compile.cc
+++ b/gcc/rust/backend/rust-compile.cc
@@ -161,13 +161,6 @@ HIRCompileBase::coercion_site1 (tree rvalue, const TyTy::BaseType *rval,
 				    lvalue_locus, rvalue_locus))
 	return error_mark_node;
     }
-  else if (expected->get_kind () == TyTy::TypeKind::DYNAMIC
-	   && actual->get_kind () != TyTy::TypeKind::DYNAMIC)
-    {
-      const TyTy::DynamicObjectType *dyn
-	= static_cast<const TyTy::DynamicObjectType *> (expected);
-      return coerce_to_dyn_object (rvalue, actual, expected, dyn, rvalue_locus);
-    }
   else if (expected->get_kind () == TyTy::TypeKind::SLICE)
     {
       // bad coercion
@@ -182,7 +175,7 @@ HIRCompileBase::coercion_site1 (tree rvalue, const TyTy::BaseType *rval,
 
       // return an unsized coercion
       Resolver::Adjustment unsize_adj (
-	Resolver::Adjustment::AdjustmentType::UNSIZE, expected);
+	Resolver::Adjustment::AdjustmentType::UNSIZE, actual, expected);
       return resolve_unsized_adjustment (unsize_adj, rvalue, rvalue_locus);
     }
 
@@ -192,7 +185,6 @@ HIRCompileBase::coercion_site1 (tree rvalue, const TyTy::BaseType *rval,
 tree
 HIRCompileBase::coerce_to_dyn_object (tree compiled_ref,
 				      const TyTy::BaseType *actual,
-				      const TyTy::BaseType *expected,
 				      const TyTy::DynamicObjectType *ty,
 				      Location locus)
 {