Fails glLinkProgram if two glBindAttribLocation conflicts.

gpu/command_buffer/service/program_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/program_manager.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
@@ skipping 150 matching lines @@
   }
   valid_ = true;
 }
 
 void ProgramManager::ProgramInfo::Link() {
   ClearLinkStatus();
   if (!CanLink()) {
     set_log_info("missing shaders");
     return;
   }
+  if (DetectAttribLocationBindingConflicts()) {
+    set_log_info("glBindAttribLocation() conflicts");
+    return;
+  }
 
   glLinkProgram(service_id());
   GLint success = 0;
   glGetProgramiv(service_id(), GL_LINK_STATUS, &success);
   if (success) {
     Update();
   } else {
     UpdateLogInfo();
   }
 }
@@ skipping 254 matching lines @@
 
 bool ProgramManager::ProgramInfo::CanLink() const {
   for (int ii = 0; ii < kMaxAttachedShaders; ++ii) {
     if (!attached_shaders_[ii] || !attached_shaders_[ii]->IsValid()) {
       return false;
     }
   }
   return true;
 }
 
+bool ProgramManager::ProgramInfo::DetectAttribLocationBindingConflicts() const {
+  std::map<GLint, int> location_binding_count;

[greggman, 2012/03/01 22:49:36]

could this just be std::set<GLint>? 

+  for (std::map<std::string, GLint>::const_iterator it =
+           bind_attrib_location_map_.begin();
+       it != bind_attrib_location_map_.end(); ++it) {
+    // Find out if an attribute is declared in this program's shaders.
+    bool active = false;
+    for (int ii = 0; ii < kMaxAttachedShaders; ++ii) {
+      if (!attached_shaders_[ii] || !attached_shaders_[ii]->IsValid())
+        continue;
+      if (attached_shaders_[ii]->GetAttribInfo(it->first)) {
+        active = true;
+        break;
+      }
+    }
+    if (active) {

[greggman, 2012/03/01 22:49:36]

If location_binding_count is a set then this would just be

std::pair<std::set<GLint> >::iterator, bool> result =
  location_binding_used_.insert(it->second);
if (result.second) {
  return true;
}

+      if (location_binding_count.count(it->second) > 0)
+        return true;
+      location_binding_count[it->second] = 1;
+    }
+  }
+  return false;
+}
+
 static uint32 ComputeOffset(const void* start, const void* position) {
   return static_cast<const uint8*>(position) -
          static_cast<const uint8*>(start);
 }
 
 void ProgramManager::ProgramInfo::GetProgramInfo(
     ProgramManager* manager, CommonDecoder::Bucket* bucket) const {
   // NOTE: It seems to me the math in here does not need check for overflow
   // because the data being calucated from has various small limits. The max
   // number of attribs + uniforms is somewhere well under 1024. The maximum size
@@ skipping 194 matching lines @@
 }
 
 GLint ProgramManager::UnswizzleLocation(GLint v) const {
   return v < 0 ? v : Swizzle(v - uniform_swizzle_);
 }
 
 }  // namespace gles2
 }  // namespace gpu