llvm-project/lldb/source/Plugins/Platform/MacOSX/PlatformRemoteiOS.cpp
Jonas Devlieghere 8faca2ed6a [lldb] Fix platform selection on Apple Silicon
Currently, when connecting to a remote iOS device from the command line
on Apple Silicon, we end up using the host platform (PlatfromMacOSX)
instead of remote-ios (PlatformRemoteiOS). This happens because
PlatfromMacOSX includes arm64-apple-ios and arm64e-apple-ios as
compatible architectures, presumably to support debugging iOS Apps on
Apple Silicon [1].

This is a problem for debugging remote ios devices, because the host
platform doesn't look for an expanded shared cache on disk and as a
result we end up reading everything from memory, incurring a significant
performance hit.

The crux of this patch is to make PlatfromMacOSX *not* compatible with
arm64(e)-apple-ios. This also means that we now use remote-ios
(PlatformRemoteiOS) as the platform for debugging iOS apps on Apple
Silicon. This has the (unintended) side effect that unlike we do for the
host platform, we no longer check our local shared cache, and incur a
performance hit on debugging these apps.

To avoid that, PlatformRemoteiOS now also check the local cache to
support this use case, which is cheap enough to do unconditionally for
PlatformRemoteiOS.

[1] https://support.apple.com/guide/app-store/iphone-ipad-apps-mac-apple-silicon-fird2c7092da/mac

Differential revision: https://reviews.llvm.org/D117340
2022-01-14 16:03:49 -08:00

156 lines
4.4 KiB
C++

//===-- PlatformRemoteiOS.cpp ---------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "PlatformRemoteiOS.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleList.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Host/Host.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/FileSpec.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/StreamString.h"
using namespace lldb;
using namespace lldb_private;
LLDB_PLUGIN_DEFINE(PlatformRemoteiOS)
// Static Variables
static uint32_t g_initialize_count = 0;
// Static Functions
void PlatformRemoteiOS::Initialize() {
PlatformDarwin::Initialize();
if (g_initialize_count++ == 0) {
PluginManager::RegisterPlugin(PlatformRemoteiOS::GetPluginNameStatic(),
PlatformRemoteiOS::GetDescriptionStatic(),
PlatformRemoteiOS::CreateInstance);
}
}
void PlatformRemoteiOS::Terminate() {
if (g_initialize_count > 0) {
if (--g_initialize_count == 0) {
PluginManager::UnregisterPlugin(PlatformRemoteiOS::CreateInstance);
}
}
PlatformDarwin::Terminate();
}
PlatformSP PlatformRemoteiOS::CreateInstance(bool force, const ArchSpec *arch) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
if (log) {
const char *arch_name;
if (arch && arch->GetArchitectureName())
arch_name = arch->GetArchitectureName();
else
arch_name = "<null>";
const char *triple_cstr =
arch ? arch->GetTriple().getTriple().c_str() : "<null>";
LLDB_LOGF(log, "PlatformRemoteiOS::%s(force=%s, arch={%s,%s})",
__FUNCTION__, force ? "true" : "false", arch_name, triple_cstr);
}
bool create = force;
if (!create && arch && arch->IsValid()) {
switch (arch->GetMachine()) {
case llvm::Triple::arm:
case llvm::Triple::aarch64:
case llvm::Triple::thumb: {
const llvm::Triple &triple = arch->GetTriple();
llvm::Triple::VendorType vendor = triple.getVendor();
switch (vendor) {
case llvm::Triple::Apple:
create = true;
break;
#if defined(__APPLE__)
// Only accept "unknown" for the vendor if the host is Apple and
// "unknown" wasn't specified (it was just returned because it was NOT
// specified)
case llvm::Triple::UnknownVendor:
create = !arch->TripleVendorWasSpecified();
break;
#endif
default:
break;
}
if (create) {
switch (triple.getOS()) {
case llvm::Triple::Darwin: // Deprecated, but still support Darwin for
// historical reasons
case llvm::Triple::IOS: // This is the right triple value for iOS
// debugging
break;
default:
create = false;
break;
}
}
} break;
default:
break;
}
}
if (create) {
if (log)
LLDB_LOGF(log, "PlatformRemoteiOS::%s() creating platform", __FUNCTION__);
return lldb::PlatformSP(new PlatformRemoteiOS());
}
if (log)
LLDB_LOGF(log, "PlatformRemoteiOS::%s() aborting creation of platform",
__FUNCTION__);
return lldb::PlatformSP();
}
llvm::StringRef PlatformRemoteiOS::GetDescriptionStatic() {
return "Remote iOS platform plug-in.";
}
/// Default Constructor
PlatformRemoteiOS::PlatformRemoteiOS()
: PlatformRemoteDarwinDevice() {}
std::vector<ArchSpec> PlatformRemoteiOS::GetSupportedArchitectures() {
std::vector<ArchSpec> result;
ARMGetSupportedArchitectures(result, llvm::Triple::IOS);
return result;
}
bool PlatformRemoteiOS::CheckLocalSharedCache() const {
// You can run iPhone and iPad apps on Mac with Apple Silicon. At the
// platform level there's no way to distinguish them from remote iOS
// applications. Make sure we still read from our own shared cache.
return true;
}
llvm::StringRef PlatformRemoteiOS::GetDeviceSupportDirectoryName() {
return "iOS DeviceSupport";
}
llvm::StringRef PlatformRemoteiOS::GetPlatformName() {
return "iPhoneOS.platform";
}