commit c1f14fbea92bcf267d39cbce937b993913dc6578
author Olli Etuaho <oetuaho@nvidia.com> Sat Oct 28 19:17:23 2017 +0300
committer Commit Bot <commit-bot@chromium.org> Tue Oct 31 20:18:46 2017 +0000
tree 2af595ff58d78e6445a0cee26117e7a256a3aa43
parent b8ee9dd35e6033293bd0644a010a5e3e2e7b484b

Remove empty switch statements from translated shaders

The native HLSL compiler does not accept switch statements with an
empty statement list. The simplest way to accommodate this is to
simply remove them from the AST after parsing and some initial
pruning.

This is done by the new RemoveEmptySwitchStatements traverser. It
preserves init statements of switch statements in case they have side
effects. So for example

switch(++i) {}

gets translated to

++i;

BUG=angleproject:2206
TEST=angle_end2end_tests

Change-Id: I550a3c9b010a3566016bdfd93344ac30fd860604
Reviewed-on: https://chromium-review.googlesource.com/742922
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>

src/compiler/translator/Compiler.cpp

diff --git a/src/compiler/translator/Compiler.cpp b/src/compiler/translator/Compiler.cpp
index 82fc287..07ea1d6 100644
--- a/src/compiler/translator/Compiler.cpp
+++ b/src/compiler/translator/Compiler.cpp
@@ -28,6 +28,7 @@
 #include "compiler/translator/PruneNoOps.h"
 #include "compiler/translator/RegenerateStructNames.h"
 #include "compiler/translator/RemoveArrayLengthMethod.h"
+#include "compiler/translator/RemoveEmptySwitchStatements.h"
 #include "compiler/translator/RemoveInvariantDeclaration.h"
 #include "compiler/translator/RemoveNoOpCasesFromEndOfSwitchStatements.h"
 #include "compiler/translator/RemovePow.h"
@@ -393,6 +394,9 @@
         if (success)
             RemoveNoOpCasesFromEndOfSwitchStatements(root, &symbolTable);
 
+        // Remove empty switch statements - this makes output simpler.
+        RemoveEmptySwitchStatements(root);
+
         // Create the function DAG and check there is no recursion
         if (success)
             success = initCallDag(root);