From 9894867678c389089360bc32886fc89073e26c2d Mon Sep 17 00:00:00 2001
From: Ben Clayton <bclayton@google.com>
Date: Tue, 5 Jan 2021 20:53:10 +0000
Subject: [PATCH] reader/wgsl: Fix parsing of matrices.

https://gpuweb.github.io/gpuweb/wgsl.html#matrix-types :
"matNxM<T>	Matrix of N columns and M rows"

Fixed: tint:432
Change-Id: Ib8fdb836b02c5e6be87acea850f095355545adbd
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/36421
Auto-Submit: Ben Clayton <bclayton@google.com>
Commit-Queue: dan sinclair <dsinclair@chromium.org>
Reviewed-by: dan sinclair <dsinclair@chromium.org>
---
 src/reader/wgsl/parser_impl.cc                | 8 ++++----
 src/reader/wgsl/parser_impl_type_decl_test.cc | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/reader/wgsl/parser_impl.cc b/src/reader/wgsl/parser_impl.cc
index 9aaea82c7a..493ac840d1 100644
--- a/src/reader/wgsl/parser_impl.cc
+++ b/src/reader/wgsl/parser_impl.cc
@@ -1110,14 +1110,14 @@ Expect<ast::type::Type*> ParserImpl::expect_type_decl_matrix(Token t) {
   uint32_t rows = 2;
   uint32_t columns = 2;
   if (t.IsMat3x2() || t.IsMat3x3() || t.IsMat3x4()) {
-    rows = 3;
+    columns = 3;
   } else if (t.IsMat4x2() || t.IsMat4x3() || t.IsMat4x4()) {
-    rows = 4;
+    columns = 4;
   }
   if (t.IsMat2x3() || t.IsMat3x3() || t.IsMat4x3()) {
-    columns = 3;
+    rows = 3;
   } else if (t.IsMat2x4() || t.IsMat3x4() || t.IsMat4x4()) {
-    columns = 4;
+    rows = 4;
   }
 
   const char* use = "matrix";
diff --git a/src/reader/wgsl/parser_impl_type_decl_test.cc b/src/reader/wgsl/parser_impl_type_decl_test.cc
index 6c11ba1cbe..9251526c23 100644
--- a/src/reader/wgsl/parser_impl_type_decl_test.cc
+++ b/src/reader/wgsl/parser_impl_type_decl_test.cc
@@ -604,8 +604,8 @@ TEST_F(ParserImplTest, TypeDecl_Array_MissingComma) {
 
 struct MatrixData {
   const char* input;
-  size_t rows;
   size_t columns;
+  size_t rows;
 };
 inline std::ostream& operator<<(std::ostream& out, MatrixData data) {
   out << std::string(data.input);