commit c1346fba608e11a8f4e7fc0d4c85d5dcf6a0b8df
author Corentin Wallez <cwallez@chromium.org> Thu Aug 24 16:11:26 2017 +0000
committer Commit Bot <commit-bot@chromium.org> Thu Aug 24 16:11:59 2017 +0000
tree 26f5887b535bd62ac21d575343f76f395bb406d0
parent e080387e435fae181b65cf71a71b02c6354c374e

Revert "Remove IndexRange retrieving in validation"

This reverts commit 59d9da089580afac175ff5f1a932b987c9d194d6.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Remove IndexRange retrieving in validation
> 
> This change can improve the performance of drawElements which uses
> the path without translation.
> Paste a set of mean data (repeated 30) for reference on Intel skylake
> Win10 desktop.
> DrawElementsPerfBenchmark.Run/d3d11:
> before                     after
> mean: 13644.4666667 -> mean: 13887.8333333
> DrawElementsPerfBenchmark.Run/d3d11_index_buffer_changed:
> before                     after
> mean: 45.8          -> mean: 46.3666666667
> 
> BUG=755897, angleproject:1393
> 
> Change-Id: I11f5db25445346958dfef52b1d23df5483cda32f
> Reviewed-on: https://chromium-review.googlesource.com/607413
> Reviewed-by: Geoff Lang <geofflang@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>

TBR=geofflang@chromium.org,jmadill@chromium.org,jiajia.qin@intel.com

Change-Id: I4b00af2c32af36aa978ac2fddcf7514134497cf3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 755897, angleproject:1393
Reviewed-on: https://chromium-review.googlesource.com/633296
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

src/libANGLE/validationES.cpp

diff --git a/src/libANGLE/validationES.cpp b/src/libANGLE/validationES.cpp
index a878aed..6b9b390 100644
--- a/src/libANGLE/validationES.cpp
+++ b/src/libANGLE/validationES.cpp
@@ -3171,13 +3171,34 @@
         }
     }
 
-    // Here we use maxVertex = 0 and vertexCount = 1 to avoid retrieving IndexRange.
-    if (!ValidateDrawAttribs(context, primcount, 0, 1))
+    // Use the parameter buffer to retrieve and cache the index range.
+    // TODO: offer fast path, with disabled index validation.
+    // TODO: also disable index checking on back-ends that are robust to out-of-range accesses.
+    const auto &params        = context->getParams<HasIndexRange>();
+    const auto &indexRangeOpt = params.getIndexRange();
+    if (!indexRangeOpt.valid())
+    {
+        // Unexpected error.
+        return false;
+    }
+
+    // If we use an index greater than our maximum supported index range, return an error.
+    // The ES3 spec does not specify behaviour here, it is undefined, but ANGLE should always
+    // return an error if possible here.
+    if (static_cast<GLuint64>(indexRangeOpt.value().end) >= context->getCaps().maxElementIndex)
+    {
+        ANGLE_VALIDATION_ERR(context, InvalidOperation(), ExceedsMaxElement);
+        return false;
+    }
+
+    if (!ValidateDrawAttribs(context, primcount, static_cast<GLint>(indexRangeOpt.value().end),
+                             static_cast<GLint>(indexRangeOpt.value().vertexCount())))
     {
         return false;
     }
 
-    return true;
+    // No op if there are no real indices in the index data (all are primitive restart).
+    return (indexRangeOpt.value().vertexIndexCount > 0);
 }
 
 bool ValidateDrawElementsInstancedCommon(ValidationContext *context,