program_manager: detect interface block mismatches

This fixes the deqp/data/gles3/shaders/linkage.html tests that were
checking that compilation fail if interface blocks have different
layouts.

BUG=621031
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_optional_gpu_tests_rel;tryserver.chromium.mac:mac_optional_gpu_tests_rel;tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2147663002
Cr-Commit-Position: refs/heads/master@{#405256}

gpu/command_buffer/service/program_manager.cc

@@ -1073,6 +1073,14 @@ bool Program::Link(ShaderManager* manager,
       set_log_info("glBindUniformLocationCHROMIUM() conflicts");
       return false;
     }
+    if (DetectInterfaceBlocksMismatch(&conflicting_name)) {
+      std::string info_log =
+          "Interface blocks with the same name but different"
+          " fields/layout: " +
+          conflicting_name;
+      set_log_info(ProcessLogInfo(info_log).c_str());
+      return false;
+    }
     if (DetectVaryingsMismatch(&conflicting_name)) {
       std::string info_log = "Varyings with the same name but different type, "
                              "or statically used varyings in fragment shader "
@@ -1620,6 +1628,29 @@ bool Program::DetectUniformsMismatch(std::string* conflicting_name) const {
   return false;
 }
 
+bool Program::DetectInterfaceBlocksMismatch(
+    std::string* conflicting_name) const {
+  std::map<std::string, const sh::InterfaceBlock*> interface_pointer_map;
+  for (auto shader : attached_shaders_) {
+    const InterfaceBlockMap& shader_interfaces = shader->interface_block_map();
+    for (const auto& it : shader_interfaces) {
+      const auto& name = it.first;
+      auto hit = interface_pointer_map.find(name);
+      if (hit == interface_pointer_map.end()) {
+        interface_pointer_map[name] = &(it.second);
+      } else {
+        // If an interface is in the map, i.e., it has already been declared by
+        // another shader, then the layout must match.
+        if (hit->second->isSameInterfaceBlockAtLinkTime(it.second))
+          continue;
+        *conflicting_name = name;
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 bool Program::DetectVaryingsMismatch(std::string* conflicting_name) const {
   DCHECK(attached_shaders_[0].get() &&
          attached_shaders_[0]->shader_type() == GL_VERTEX_SHADER &&

gpu/command_buffer/service/program_manager.h

@@ -345,6 +345,10 @@ class GPU_EXPORT Program : public base::RefCounted<Program> {
   // conflicting_name if such cases are detected.
   bool DetectUniformsMismatch(std::string* conflicting_name) const;
 
+  // Detects if there are interface blocks of the same name but different
+  // layouts.
+  bool DetectInterfaceBlocksMismatch(std::string* conflicting_name) const;
+
   // Return true if a varying is statically used in fragment shader, but it
   // is not declared in vertex shader.
   bool DetectVaryingsMismatch(std::string* conflicting_name) const;