Compiler: fixed wrong codegen for virtual structs. Fixes #2551

crystal-lang · May 3, 2016 · a90921c · a90921c
1 parent 9c7f351
commit a90921c
Showing 3 changed files with 144 additions and 3 deletions.
diff --git a/spec/compiler/codegen/struct_spec.cr b/spec/compiler/codegen/struct_spec.cr
@@ -381,4 +381,133 @@ describe "Code gen: struct" do
       ptr.value.x
       )).to_i.should eq(1)
   end
+
+  it "codegens virtual struct metaclass (#2551) (1)" do
+    run(%(
+      abstract struct Foo
+        def initialize
+          @x = 21
+        end
+
+        def x
+          a = @x
+          a
+        end
+      end
+
+      struct Bar < Foo
+        def initialize
+          @x = 42
+        end
+      end
+
+      struct Baz < Foo
+      end
+
+      (Bar.new as Foo).x
+      # (Bar || Baz).new.x
+      )).to_i.should eq(42)
+  end
+
+  it "codegens virtual struct metaclass (#2551) (2)" do
+    run(%(
+      abstract struct Foo
+        def initialize
+          @x = 21
+        end
+      end
+
+      struct Bar < Foo
+        def initialize
+          @x = 42
+        end
+      end
+
+      struct Baz < Foo
+      end
+
+      (Bar.new as Foo).@x
+      )).to_i.should eq(42)
+  end
+
+  it "codegens virtual struct metaclass (#2551) (3)" do
+    run(%(
+      abstract struct Foo
+        def initialize
+          @x = 21
+        end
+
+        def x
+          @x
+        end
+      end
+
+      struct Bar < Foo
+        def initialize
+          @x = 42
+        end
+      end
+
+      struct Baz < Foo
+      end
+
+      (Bar.new as Foo).x
+      )).to_i.should eq(42)
+  end
+
+  it "codegens virtual struct metaclass (#2551) (4)" do
+    run(%(
+      abstract struct Foo
+        def initialize
+          @x = 21
+        end
+
+        def x
+          a = @x
+          a
+        end
+      end
+
+      struct Bar < Foo
+        def initialize
+          @x = 42
+        end
+      end
+
+      struct Baz < Foo
+      end
+
+      (Bar || Baz).new.x
+      )).to_i.should eq(42)
+  end
+
+  it "mutates a  virtual struct" do
+    run(%(
+      abstract struct Foo
+        def initialize
+          @x = 21
+        end
+
+        def x=(@x)
+        end
+
+        def x
+          @x
+        end
+      end
+
+      struct Bar < Foo
+        def initialize
+          @x = 42
+        end
+      end
+
+      struct Baz < Foo
+      end
+
+      foo = Bar.new as Foo
+      foo.x = 84
+      foo.x
+      )).to_i.should eq(84)
+  end
 end
diff --git a/src/compiler/crystal/codegen/codegen.cr b/src/compiler/crystal/codegen/codegen.cr
@@ -1462,7 +1462,13 @@ module Crystal
     def llvm_self_ptr
       type = context.type
       if type.is_a?(VirtualType)
-        cast_to llvm_self, type.base_type
+        if type.struct?
+          # A virtual struct doesn't need a cast to a more generic pointer
+          # (it's the union already)
+          llvm_self
+        else
+          cast_to llvm_self, type.base_type
+        end
       else
         llvm_self
       end
@@ -1832,7 +1838,13 @@ module Crystal
       end
 
       if type.is_a?(VirtualType)
-        pointer = cast_to pointer, type.base_type
+        if type.struct?
+          # For a struct we need to cast the second part of the union to the base type
+          value_ptr = gep(pointer, 0, 1)
+          pointer = bit_cast value_ptr, llvm_type(type.base_type).pointer
+        else
+          pointer = cast_to pointer, type.base_type
+        end
       end
 
       aggregate_index pointer, index

diff --git a/src/compiler/crystal/codegen/primitives.cr b/src/compiler/crystal/codegen/primitives.cr
@@ -414,7 +414,7 @@ class Crystal::CodeGenVisitor
     end
 
     if type.is_a?(VirtualType)
-      @last = cast_to @last, type
+      @last = upcast(@last, type, base_type)
     end
 
     @last