GLSL: move entry point handling to CanonicalizeEntryPointIO transform.

Move builtin_to_string() and builtin_type() to
the CanonicalizeEntryPointIO transform. Use the former to
rename entry point IO variables to the gl_ names, and the latter
to cast values to the correct type.

Change-Id: Iddfad574ddd660ff1bfd89a399a001b967b6b67e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/78380
Reviewed-by: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>

test/array/assign_to_function_var.wgsl.expected.glsl

@@ -5,11 +5,6 @@ layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void unused_entry_point() {
   return;
 }
-
-void main() {
-  unused_entry_point();
-}
-
 struct S {
   ivec4 arr[4];
 };

test/array/assign_to_private_var.wgsl.expected.glsl

@@ -5,11 +5,6 @@ layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void unused_entry_point() {
   return;
 }
-
-void main() {
-  unused_entry_point();
-}
-
 struct S {
   ivec4 arr[4];
 };

test/array/assign_to_storage_var.wgsl.expected.glsl

@@ -5,11 +5,6 @@ layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void unused_entry_point() {
   return;
 }
-
-void main() {
-  unused_entry_point();
-}
-
 struct S {
   ivec4 arr[4];
 };

test/array/assign_to_subexpr.wgsl.expected.glsl

@@ -5,11 +5,6 @@ layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void unused_entry_point() {
   return;
 }
-
-void main() {
-  unused_entry_point();
-}
-
 struct S {
   int arr[4];
 };

test/array/assign_to_workgroup_var.wgsl.expected.glsl

@@ -5,11 +5,6 @@ layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void unused_entry_point() {
   return;
 }
-
-void main() {
-  unused_entry_point();
-}
-
 struct S {
   ivec4 arr[4];
 };

test/array/function_parameter.wgsl.expected.glsl

@@ -13,7 +13,6 @@ float f3(float a[2][3][4]) {
   return a[1][2][3];
 }
 
-layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void tint_symbol() {
   float a1[4] = float[4](0.0f, 0.0f, 0.0f, 0.0f);
   float a2[3][4] = float[3][4](float[4](0.0f, 0.0f, 0.0f, 0.0f), float[4](0.0f, 0.0f, 0.0f, 0.0f), float[4](0.0f, 0.0f, 0.0f, 0.0f));
@@ -21,10 +20,10 @@ void tint_symbol() {
   float v1 = f1(a1);
   float v2 = f2(a2);
   float v3 = f3(a3);
-  return;
 }
 
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void main() {
   tint_symbol();
+  return;
 }
-

test/array/function_return_type.wgsl.expected.glsl

@@ -16,15 +16,14 @@ float[2][3][4] f3() {
   return tint_symbol_3;
 }
 
-layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void tint_symbol() {
   float a1[4] = f1();
   float a2[3][4] = f2();
   float a3[2][3][4] = f3();
-  return;
 }
 
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void main() {
   tint_symbol();
+  return;
 }
-

test/array/size.wgsl.expected.glsl

@@ -10,10 +10,9 @@ void tint_symbol() {
   float unsigned_constant[4] = float[4](0.0f, 0.0f, 0.0f, 0.0f);
   signed_literal = unsigned_constant;
   signed_constant = unsigned_literal;
-  return;
 }
 
 void main() {
   tint_symbol();
+  return;
 }
-

test/array/type_constructor.wgsl.expected.glsl

@@ -1,7 +1,6 @@
 #version 310 es
 precision mediump float;
 
-layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void tint_symbol() {
   int x = 42;
   int empty[4] = int[4](0, 0, 0, 0);
@@ -36,10 +35,10 @@ void tint_symbol() {
   int tint_symbol_19[4] = int[4](1, x, (x + 1), nonempty[3]);
   int tint_symbol_20[2][4] = int[2][4](tint_symbol_19, nested_nonempty[1][2]);
   int subexpr_nested_nonempty_with_expr[4] = tint_symbol_20[1];
-  return;
 }
 
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 void main() {
   tint_symbol();
+  return;
 }
-