Look at chromium-vaapi build in rpmfusion. пн, 11 мар. 2019 г., 20:17 Tom Callaway <tcall...@redhat.com>:
> Hi folks, > > I spent some time this weekend trying to get Chromium 72 building on > Fedora, but I kept running into a C++ issue that I was not able to resolve. > This happened with gcc-9.0.1-0.8.fc30.x86_64 and gcc-8.3.1-2.fc29.x86_64. > > Here's a sample of the error (it happens in a few places), from Fedora 30: > > In file included from > ../../base/trace_event/trace_event_system_stats_monitor.h:15, > from ../../base/trace_event/trace_event.h:26, > from ../../base/threading/scoped_blocking_call.cc:11: > ../../base/trace_event/trace_log.h: In constructor > 'base::ScopedBlockingCall::ScopedBlockingCall(base::BlockingType)': > ../../base/threading/scoped_blocking_call.cc:88:5: in 'constexpr' > expansion of > 'base::trace_event::TraceLog::GetBuiltinCategoryEnabled(((const > char*)"base"))' > ../../base/trace_event/trace_log.h:215:25: error: '((& > base::trace_event::CategoryRegistry::categories_[7]) != 0)' is not a > constant expression > 215 | if (builtin_category) > | ^ > > Now, chromium isn't the easiest code base to work with, but what seems to > be happening is that this code calls one of the TRACE_EVENT macros, like > this from base/threading/scoped_blocking_call.cc: > > TRACE_EVENT_BEGIN1("base", "ScopedBlockingCall", "blocking_type", > static_cast<int>(blocking_type)); > > Those macros are defined in base/trace_event/common/trace_event_common.h: > > #define TRACE_EVENT_BEGIN1(category_group, name, arg1_name, arg1_val) \ > INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category_group, name, \ > TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val) > > INTERNAL_TRACE_EVENT_ADD() is defined in base/trace_event/trace_event.h: > > / Implementation detail: internal macro to create static category and add > // event if the category is enabled. > #define INTERNAL_TRACE_EVENT_ADD(phase, category_group, name, flags, ...) > \ > do { > \ > INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); > \ > if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED()) { > \ > trace_event_internal::AddTraceEvent( > \ > phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, > \ > trace_event_internal::kGlobalScope, trace_event_internal::kNoId, > \ > flags, trace_event_internal::kNoId, ##__VA_ARGS__); > \ > } > \ > } while (0) > > INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO is also defined in > base/trace_event/trace_event.h: > > #define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group) > \ > static_assert( > \ > > base::trace_event::BuiltinCategories::IsAllowedCategory(category_group), \ > "Unknown tracing category is used. Please register your " > \ > "category in base/trace_event/builtin_categories.h"); > \ > constexpr const unsigned char* INTERNAL_TRACE_EVENT_UID( > \ > k_category_group_enabled) = > \ > > base::trace_event::TraceLog::GetBuiltinCategoryEnabled(category_group); \ > const unsigned char* INTERNAL_TRACE_EVENT_UID(category_group_enabled); > \ > INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_MAYBE_AT_COMPILE_TIME( > \ > category_group, INTERNAL_TRACE_EVENT_UID(k_category_group_enabled), > \ > INTERNAL_TRACE_EVENT_UID(category_group_enabled)); > > Finally, inside here, it > calls base::trace_event::TraceLog::GetBuiltinCategoryEnabled(), which is > defined in base/trace_event/trace_log.h: > > // Called by TRACE_EVENT* macros, don't call this directly. > // The name parameter is a category group for example: > // TRACE_EVENT0("renderer,webkit", "WebViewImpl::HandleInputEvent") > static const unsigned char* GetCategoryGroupEnabled(const char* name); > static const char* GetCategoryGroupName( > const unsigned char* category_group_enabled); > static constexpr const unsigned char* GetBuiltinCategoryEnabled( > const char* name) { > TraceCategory* builtin_category = > CategoryRegistry::GetBuiltinCategoryByName(name); > if (builtin_category) > return builtin_category->state_ptr(); > return nullptr; > } > > Okay, so what seems like is happening here, is that the calls like this: > > TRACE_EVENT_BEGIN1("base", "ScopedBlockingCall", "blocking_type", > static_cast<int>(blocking_type)); > > Are passing "base" (that first var) all the way into > GetCategoryGroupEnabled, which is finding it via GetBuiltinCategoryByName() > in base/trace_event/category_registry.h, checking against the list in > INTERNAL_TRACE_LIST_BUILTIN_CATEGORIES(X) > from base/trace_event/builtin_categories.h, finding it, then returning this > as builtin_category: > > (& base::trace_event::CategoryRegistry::categories_[7]) > > When if(builtin_category) is run (trying to check to see if we got a > buillt-in category or a nullptr, I think), thats when GCC says: > > error: '((& base::trace_event::CategoryRegistry::categories_[7]) != 0)' is > not a constant expression > > ***** > > None of the other distros that build Chromium seem to have hit this issue, > nor does it appear in any bugs I could find with upstream (but they use a > fork of clang to build, and we use gcc). I have hit the limit of my C++ > knowledge here, so I'm not sure how to fix this. If you can help me, it > would be greatly appreciated. My work in progress is checked into the > master chromium branch in git. > > There are quite a few security issues that this new version fixes, > including some that are being actively exploited, so timely help here is > appreciated. > > Thanks, > > ~tom > > _______________________________________________ > devel mailing list -- devel@lists.fedoraproject.org > To unsubscribe send an email to devel-le...@lists.fedoraproject.org > Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines > List Archives: > https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org >
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