Author: Vedant Kumar Date: 2021-03-10T13:57:10-08:00 New Revision: ac29c35207a506eedaaea8a4196b83facbf978da
URL: https://github.com/llvm/llvm-project/commit/ac29c35207a506eedaaea8a4196b83facbf978da DIFF: https://github.com/llvm/llvm-project/commit/ac29c35207a506eedaaea8a4196b83facbf978da.diff LOG: [lldb/Platform] Skip very slow xcrun queries for simulator platforms, NFC GetXcodeSDK() consistently takes over 1 second to complete if the queried SDK is missing, because `xcrun` doesn't cache negative lookups. Because there are multiple simulator platforms, this can add 4+ seconds to `lldb -b some_object_file.o`. To work around this, skip the call to GetXcodeSDK() when setting up simulator platforms if the specified arch doesn't have what looks like a simulator triple. Some other ways to fix this: - Fix caching in xcrun (rdar://74882205) - Test for arch compat before calling SomePlatform::CreateInstance() (much larger change) Differential Revision: https://reviews.llvm.org/D98272 Added: Modified: lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.cpp Removed: ################################################################################ diff --git a/lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.cpp b/lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.cpp index 342f7c214a76..afbffc2ef0a3 100644 --- a/lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.cpp +++ b/lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.cpp @@ -505,6 +505,16 @@ uint32_t PlatformAppleSimulator::FindProcesses( return process_infos.size(); } +/// Whether to skip creating a simulator platform. +static bool shouldSkipSimulatorPlatform(bool force, const ArchSpec *arch) { + // If the arch is known not to specify a simulator environment, skip creating + // the simulator platform (we can create it later if there's a matching arch). + // This avoids very slow xcrun queries for non-simulator archs (the slowness + // is due to xcrun not caching negative queries (rdar://74882205)). + return !force && arch && arch->IsValid() && + !arch->TripleEnvironmentWasSpecified(); +} + static llvm::StringRef GetXcodeSDKDir(std::string preferred, std::string secondary) { llvm::StringRef sdk; @@ -530,6 +540,8 @@ struct PlatformiOSSimulator { } static PlatformSP CreateInstance(bool force, const ArchSpec *arch) { + if (shouldSkipSimulatorPlatform(force, arch)) + return nullptr; llvm::StringRef sdk; sdk = HostInfo::GetXcodeSDKPath(XcodeSDK("iPhoneSimulator.Internal.sdk")); if (sdk.empty()) @@ -578,6 +590,8 @@ struct PlatformAppleTVSimulator { } static PlatformSP CreateInstance(bool force, const ArchSpec *arch) { + if (shouldSkipSimulatorPlatform(force, arch)) + return nullptr; return PlatformAppleSimulator::CreateInstance( "PlatformAppleTVSimulator", g_tvos_description, ConstString(g_tvos_plugin_name), @@ -619,6 +633,8 @@ struct PlatformAppleWatchSimulator { } static PlatformSP CreateInstance(bool force, const ArchSpec *arch) { + if (shouldSkipSimulatorPlatform(force, arch)) + return nullptr; return PlatformAppleSimulator::CreateInstance( "PlatformAppleWatchSimulator", g_watchos_description, ConstString(g_watchos_plugin_name), _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
