GIMPLE coversions for ArrayIndexExpr and Arrays with values

This compiles the ArrayIndexExpressions and Arrays such as:
  let x = [1,2,3];
  let a = x[0];

Addresses: #55

6 files changed, 143 insertions, 6 deletions

diff --git a/gcc/rust/analysis/rust-type-resolution.cc b/gcc/rust/analysis/rust-type-resolution.cc
index 5500faf..541acd0 100644
--- a/gcc/rust/analysis/rust-type-resolution.cc
+++ b/gcc/rust/analysis/rust-type-resolution.cc
@@ -466,7 +466,17 @@ void
 TypeResolution::visit (AST::ArrayExpr &expr)
 {
   auto elements = expr.get_internal_elements ();
+
+  auto before = typeBuffer.size ();
   elements->accept_vis (*this);
+  if (typeBuffer.size () <= before)
+    {
+      rust_error_at (expr.get_locus_slow (),
+		     "unable to determine type for ArrayExpr");
+      return;
+    }
+
+  expr.set_inferred_type (typeBuffer.back ());
 }
 
 void
diff --git a/gcc/rust/ast/rust-expr.h b/gcc/rust/ast/rust-expr.h
index d3e7cbd..4971041 100644
--- a/gcc/rust/ast/rust-expr.h
+++ b/gcc/rust/ast/rust-expr.h
@@ -1000,6 +1000,10 @@ class ArrayExpr : public ExprWithoutBlock
 
   Location locus;
 
+  // this is a reference to what the inferred type is based on
+  // this init expression
+  Type *inferredType;
+
 public:
   std::string as_string () const override;
 
@@ -1050,6 +1054,9 @@ public:
 
   ArrayElems *get_internal_elements () { return internal_elements.get (); };
 
+  Type *get_inferred_type () { return inferredType; }
+  void set_inferred_type (Type *type) { inferredType = type; }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */
diff --git a/gcc/rust/ast/rust-type.h b/gcc/rust/ast/rust-type.h
index 301b664..089aaeb 100644
--- a/gcc/rust/ast/rust-type.h
+++ b/gcc/rust/ast/rust-type.h
@@ -576,6 +576,10 @@ public:
 
   Type *get_element_type () { return elem_type.get (); }
 
+  Expr *get_size_expr () { return size.get (); }
+
+  Location &get_locus () { return locus; }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */
diff --git a/gcc/rust/backend/rust-compile.cc b/gcc/rust/backend/rust-compile.cc
index 0b632b7..2dbce16 100644
--- a/gcc/rust/backend/rust-compile.cc
+++ b/gcc/rust/backend/rust-compile.cc
@@ -503,19 +503,102 @@ Compilation::visit (AST::CompoundAssignmentExpr &expr)
 void
 Compilation::visit (AST::GroupedExpr &expr)
 {}
-// void Compilation::visit(ArrayElems& elems) {}
+
 void
 Compilation::visit (AST::ArrayElemsValues &elems)
-{}
+{
+  std::vector< ::Bexpression *> elements;
+
+  bool failed = false;
+  elems.iterate ([&] (AST::Expr *expr) mutable -> bool {
+    Bexpression *value = nullptr;
+    VISIT_POP (expr.get_locus_slow (), expr, value, exprs);
+    if (value == nullptr)
+      {
+	rust_fatal_error (expr->get_locus_slow (),
+			  "failed to compile value to array initialiser");
+	return false;
+      }
+    elements.push_back (value);
+    return true;
+  });
+
+  // nothing to do when its failed
+  if (failed)
+    return;
+
+  arrayConsStack.push_back (elements);
+}
+
 void
 Compilation::visit (AST::ArrayElemsCopied &elems)
 {}
+
 void
 Compilation::visit (AST::ArrayExpr &expr)
-{}
+{
+  translatedType = nullptr;
+  expr.get_inferred_type ()->accept_vis (*this);
+  if (translatedType == nullptr)
+    {
+      rust_error_at (expr.get_locus_slow (),
+		     "failed to compile array type for ArrayExpr");
+      return;
+    }
+
+  ::Btype *compiledType = translatedType;
+  translatedType = nullptr;
+
+  auto before = arrayConsStack.size ();
+  expr.get_internal_elements ()->accept_vis (*this);
+  if (arrayConsStack.size () <= before)
+    {
+      rust_error_at (expr.get_locus_slow (),
+		     "failed to compile the array constructor");
+      return;
+    }
+  std::vector< ::Bexpression *> initializer = arrayConsStack.back ();
+  arrayConsStack.pop_back ();
+
+  std::vector<unsigned long> indexes;
+  for (unsigned long i = 0; i < initializer.size (); ++i)
+    indexes.push_back (i);
+
+  Bexpression *cons
+    = backend->array_constructor_expression (compiledType, indexes, initializer,
+					     expr.get_locus_slow ());
+  exprs.push_back (cons);
+}
+
 void
 Compilation::visit (AST::ArrayIndexExpr &expr)
-{}
+{
+  Bexpression *arrayExpr = nullptr;
+  VISIT_POP (expr.get_array_expr ()->get_locus_slow (), expr.get_array_expr (),
+	     arrayExpr, exprs);
+  if (arrayExpr == nullptr)
+    {
+      rust_error_at (expr.get_locus_slow (),
+		     "failed to compile value to array expression reference");
+      return;
+    }
+
+  Bexpression *indexExpr = nullptr;
+  VISIT_POP (expr.get_index_expr ()->get_locus_slow (), expr.get_index_expr (),
+	     indexExpr, exprs);
+  if (indexExpr == nullptr)
+    {
+      rust_error_at (expr.get_locus_slow (),
+		     "failed to compile value to array index expression");
+      return;
+    }
+
+  Bexpression *indexExpression
+    = backend->array_index_expression (arrayExpr, indexExpr,
+				       expr.get_locus_slow ());
+  exprs.push_back (indexExpression);
+}
+
 void
 Compilation::visit (AST::TupleExpr &expr)
 {}
@@ -1376,9 +1459,34 @@ Compilation::visit (AST::RawPointerType &type)
 void
 Compilation::visit (AST::ReferenceType &type)
 {}
+
 void
 Compilation::visit (AST::ArrayType &type)
-{}
+{
+  Btype *elementType;
+  translatedType = nullptr;
+  type.get_element_type ()->accept_vis (*this);
+  if (translatedType == nullptr)
+    {
+      rust_error_at (type.get_locus (),
+		     "Failed to compile element type for array");
+      return;
+    }
+  elementType = translatedType;
+
+  Bexpression *length = nullptr;
+  VISIT_POP (type.get_size_expr ()->get_locus_slow (), type.get_size_expr (),
+	     length, exprs);
+  if (length == nullptr)
+    {
+      rust_error_at (type.get_size_expr ()->get_locus_slow (),
+		     "failed to size for array type");
+      return;
+    }
+
+  translatedType = backend->array_type (elementType, length);
+}
+
 void
 Compilation::visit (AST::SliceType &type)
 {}
diff --git a/gcc/rust/backend/rust-compile.h b/gcc/rust/backend/rust-compile.h
index ba03483..88c8318 100644
--- a/gcc/rust/backend/rust-compile.h
+++ b/gcc/rust/backend/rust-compile.h
@@ -243,7 +243,8 @@ private:
   std::vector< ::Bexpression *> exprs;
   std::vector< ::Bstatement *> stmts;
   std::vector< ::Bvariable *> varBuffer;
-  std::vector<AST::StructStruct*> structBuffer;
+  std::vector<AST::StructStruct *> structBuffer;
+  std::vector<std::vector< ::Bexpression *> > arrayConsStack;
 
   // careful these are the vectors we pass into the GCC middle-end
   std::vector< ::Btype *> type_decls;
diff --git a/gcc/testsuite/rust.test/compilable/arrays1.rs b/gcc/testsuite/rust.test/compilable/arrays1.rs
new file mode 100644
index 0000000..f7e66af
--- /dev/null
+++ b/gcc/testsuite/rust.test/compilable/arrays1.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let xs: [i32; 5] = [1, 2, 3, 4, 5];
+    let xy = [6, 7, 8];
+
+    let a = xs[0];
+    let b = xy[2];
+}