Allow length() on arbitrary array expressions
This is required to pass some dEQP GLES 3.1 tests for arrays of
arrays, and WebGL conformance tests were also recently fixed to
require this behavior. The intent of the GLSL ES spec was not to
restrict usage of length().
In practice GL drivers don't implement array length() on expressions
with side effects correctly in all cases. HLSL doesn't have an array
length operator either. Because of this we always remove array length
ops from the AST before output.
BUG=angleproject:2142
TEST=angle_unittests, angle_end2end_tests, WebGL conformance tests
Change-Id: I863a92e83ac5315b013af9a5626348482bad72b3
Reviewed-on: https://chromium-review.googlesource.com/643190
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/RemoveArrayLengthMethod.h b/src/compiler/translator/RemoveArrayLengthMethod.h
new file mode 100644
index 0000000..f4cbb14
--- /dev/null
+++ b/src/compiler/translator/RemoveArrayLengthMethod.h
@@ -0,0 +1,27 @@
+//
+// Copyright (c) 2017 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// RemoveArrayLengthMethod.h:
+// Fold array length expressions, including cases where the "this" node has side effects.
+// Example:
+// int i = (a = b).length();
+// int j = (func()).length();
+// becomes:
+// (a = b);
+// int i = <constant array length>;
+// func();
+// int j = <constant array length>;
+//
+// Must be run after SplitSequenceOperator, SimplifyLoopConditions and SeparateDeclarations steps
+// have been done to expressions containing calls of the array length method.
+
+namespace sh
+{
+
+class TIntermBlock;
+
+void RemoveArrayLengthMethod(TIntermBlock *root);
+
+} // namespace sh