[lldb] Plumb process host architecture through platform selection

To allow us to select a different platform based on where the process is
running, plumb the process host architecture through platform selection.

This patch is in preparation for D121444 which needs this functionality
to tell apart iOS binaries running on Apple Silicon vs on a remote iOS
device.

Differential revision: https://reviews.llvm.org/D121484

lldb/include/lldb/Target/Platform.h

@@ -95,7 +95,9 @@ public:
   static lldb::PlatformSP GetHostPlatform();
 
   static lldb::PlatformSP
-  GetPlatformForArchitecture(const ArchSpec &arch, ArchSpec *platform_arch_ptr);
+  GetPlatformForArchitecture(const ArchSpec &arch,
+                             const ArchSpec &process_host_arch = {},
+                             ArchSpec *platform_arch_ptr = nullptr);
 
   static const char *GetHostPlatformName();
 
@@ -107,6 +109,7 @@ public:
   static lldb::PlatformSP Create(ConstString name, Status &error);
 
   static lldb::PlatformSP Create(const ArchSpec &arch,
+                                 const ArchSpec &process_host_arch,
                                  ArchSpec *platform_arch_ptr, Status &error);
 
   /// Augments the triple either with information from platform or the host
@@ -310,7 +313,8 @@ public:
 
   /// Get the platform's supported architectures in the order in which they
   /// should be searched.
-  virtual std::vector<ArchSpec> GetSupportedArchitectures() = 0;
+  virtual std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) = 0;
 
   virtual size_t GetSoftwareBreakpointTrapOpcode(Target &target,
                                                  BreakpointSite *bp_site);
@@ -332,6 +336,7 @@ public:
   /// Lets a platform answer if it is compatible with a given architecture and
   /// the target triple contained within.
   virtual bool IsCompatibleArchitecture(const ArchSpec &arch,
+                                        const ArchSpec &process_host_arch,
                                         bool exact_arch_match,
                                         ArchSpec *compatible_arch_ptr);
 

lldb/source/Interpreter/OptionGroupPlatform.cpp

@@ -23,8 +23,8 @@ PlatformSP OptionGroupPlatform::CreatePlatformWithOptions(
   if (!m_platform_name.empty()) {
     platform_sp = Platform::Create(ConstString(m_platform_name.c_str()), error);
     if (platform_sp) {
-      if (platform_arch.IsValid() &&
+      if (platform_arch.IsValid() && !platform_sp->IsCompatibleArchitecture(
-          !platform_sp->IsCompatibleArchitecture(arch, false, &platform_arch)) {
+                                         arch, {}, false, &platform_arch)) {
         error.SetErrorStringWithFormatv("platform '{0}' doesn't support '{1}'",
                                         platform_sp->GetPluginName(),
                                         arch.GetTriple().getTriple());
@@ -33,7 +33,7 @@ PlatformSP OptionGroupPlatform::CreatePlatformWithOptions(
       }
     }
   } else if (arch.IsValid()) {
-    platform_sp = Platform::Create(arch, &platform_arch, error);
+    platform_sp = Platform::Create(arch, {}, &platform_arch, error);
   }
 
   if (platform_sp) {

lldb/source/Plugins/Platform/FreeBSD/PlatformFreeBSD.cpp

@@ -129,9 +129,10 @@ PlatformFreeBSD::PlatformFreeBSD(bool is_host)
   }
 }
 
-std::vector<ArchSpec> PlatformFreeBSD::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformFreeBSD::GetSupportedArchitectures(const ArchSpec &process_host_arch) {
   if (m_remote_platform_sp)
-    return m_remote_platform_sp->GetSupportedArchitectures();
+    return m_remote_platform_sp->GetSupportedArchitectures(process_host_arch);
   return m_supported_architectures;
 }
 

lldb/source/Plugins/Platform/FreeBSD/PlatformFreeBSD.h

@@ -43,7 +43,8 @@ public:
 
   void GetStatus(Stream &strm) override;
 
-  std::vector<ArchSpec> GetSupportedArchitectures() override;
+  std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) override;
 
   bool CanDebugProcess() override;
 

lldb/source/Plugins/Platform/Linux/PlatformLinux.cpp

@@ -128,9 +128,10 @@ PlatformLinux::PlatformLinux(bool is_host)
   }
 }
 
-std::vector<ArchSpec> PlatformLinux::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformLinux::GetSupportedArchitectures(const ArchSpec &process_host_arch) {
   if (m_remote_platform_sp)
-    return m_remote_platform_sp->GetSupportedArchitectures();
+    return m_remote_platform_sp->GetSupportedArchitectures(process_host_arch);
   return m_supported_architectures;
 }
 

lldb/source/Plugins/Platform/Linux/PlatformLinux.h

@@ -43,7 +43,8 @@ public:
 
   void GetStatus(Stream &strm) override;
 
-  std::vector<ArchSpec> GetSupportedArchitectures() override;
+  std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) override;
 
   uint32_t GetResumeCountForLaunchInfo(ProcessLaunchInfo &launch_info) override;
 

lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.cpp

@@ -266,7 +266,8 @@ CoreSimulatorSupport::Device PlatformAppleSimulator::GetSimulatorDevice() {
 }
 #endif
 
-std::vector<ArchSpec> PlatformAppleSimulator::GetSupportedArchitectures() {
+std::vector<ArchSpec> PlatformAppleSimulator::GetSupportedArchitectures(
+    const ArchSpec &process_host_arch) {
   std::vector<ArchSpec> result(m_supported_triples.size());
   llvm::transform(m_supported_triples, result.begin(),
                   [](llvm::StringRef triple) { return ArchSpec(triple); });
@@ -382,7 +383,7 @@ Status PlatformAppleSimulator::ResolveExecutable(
     StreamString arch_names;
     llvm::ListSeparator LS;
     ArchSpec platform_arch;
-    for (const ArchSpec &arch : GetSupportedArchitectures()) {
+    for (const ArchSpec &arch : GetSupportedArchitectures({})) {
       resolved_module_spec.GetArchitecture() = arch;
 
       // Only match x86 with x86 and x86_64 with x86_64...

lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.h

@@ -65,7 +65,8 @@ public:
                                lldb_private::Target &target,
                                lldb_private::Status &error) override;
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
   lldb_private::Status ResolveExecutable(
       const lldb_private::ModuleSpec &module_spec, lldb::ModuleSP &module_sp,

lldb/source/Plugins/Platform/MacOSX/PlatformDarwinKernel.cpp

@@ -909,7 +909,8 @@ Status PlatformDarwinKernel::ExamineKextForMatchingUUID(
   return {};
 }
 
-std::vector<ArchSpec> PlatformDarwinKernel::GetSupportedArchitectures() {
+std::vector<ArchSpec> PlatformDarwinKernel::GetSupportedArchitectures(
+    const ArchSpec &process_host_arch) {
   std::vector<ArchSpec> result;
 #if defined(__arm__) || defined(__arm64__) || defined(__aarch64__)
   ARMGetSupportedArchitectures(result);

lldb/source/Plugins/Platform/MacOSX/PlatformDarwinKernel.h

@@ -56,7 +56,8 @@ public:
                   llvm::SmallVectorImpl<lldb::ModuleSP> *old_modules,
                   bool *did_create_ptr) override;
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
   bool SupportsModules() override { return false; }
 

lldb/source/Plugins/Platform/MacOSX/PlatformMacOSX.cpp

@@ -133,7 +133,8 @@ ConstString PlatformMacOSX::GetSDKDirectory(lldb_private::Target &target) {
   return {};
 }
 
-std::vector<ArchSpec> PlatformMacOSX::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformMacOSX::GetSupportedArchitectures(const ArchSpec &process_host_arch) {
   std::vector<ArchSpec> result;
 #if defined(__arm__) || defined(__arm64__) || defined(__aarch64__)
   // macOS for ARM64 support both native and translated x86_64 processes

lldb/source/Plugins/Platform/MacOSX/PlatformMacOSX.h

@@ -47,7 +47,8 @@ public:
     return PlatformDarwin::GetFile(source, destination);
   }
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
   lldb_private::ConstString
   GetSDKDirectory(lldb_private::Target &target) override;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleBridge.cpp

@@ -138,7 +138,8 @@ llvm::StringRef PlatformRemoteAppleBridge::GetDescriptionStatic() {
   return "Remote BridgeOS platform plug-in.";
 }
 
-std::vector<ArchSpec> PlatformRemoteAppleBridge::GetSupportedArchitectures() {
+std::vector<ArchSpec> PlatformRemoteAppleBridge::GetSupportedArchitectures(
+    const ArchSpec &process_host_arch) {
   return {ArchSpec("arm64-apple-bridgeos")};
 }
 

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleBridge.h

@@ -40,7 +40,8 @@ public:
 
   llvm::StringRef GetDescription() override { return GetDescriptionStatic(); }
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
 protected:
   llvm::StringRef GetDeviceSupportDirectoryName() override;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleTV.cpp

@@ -133,7 +133,8 @@ llvm::StringRef PlatformRemoteAppleTV::GetDescriptionStatic() {
   return "Remote Apple TV platform plug-in.";
 }
 
-std::vector<ArchSpec> PlatformRemoteAppleTV::GetSupportedArchitectures() {
+std::vector<ArchSpec> PlatformRemoteAppleTV::GetSupportedArchitectures(
+    const ArchSpec &process_host_arch) {
   ArchSpec system_arch(GetSystemArchitecture());
 
   const ArchSpec::Core system_core = system_arch.GetCore();

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleTV.h

@@ -40,7 +40,8 @@ public:
 
   llvm::StringRef GetDescription() override { return GetDescriptionStatic(); }
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
 protected:
   llvm::StringRef GetDeviceSupportDirectoryName() override;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleWatch.cpp

@@ -144,7 +144,8 @@ llvm::StringRef PlatformRemoteAppleWatch::GetDescriptionStatic() {
 PlatformRemoteAppleWatch::PlatformRemoteAppleWatch()
     : PlatformRemoteDarwinDevice() {}
 
-std::vector<ArchSpec> PlatformRemoteAppleWatch::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformRemoteAppleWatch::GetSupportedArchitectures(const ArchSpec &host_info) {
   ArchSpec system_arch(GetSystemArchitecture());
 
   const ArchSpec::Core system_core = system_arch.GetCore();

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteAppleWatch.h

@@ -43,7 +43,8 @@ public:
 
   // lldb_private::Platform functions
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
 protected:
   llvm::StringRef GetDeviceSupportDirectoryName() override;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteDarwinDevice.cpp

@@ -92,7 +92,8 @@ Status PlatformRemoteDarwinDevice::ResolveExecutable(
     // the correct order) and see if we can find a match that way
     StreamString arch_names;
     llvm::ListSeparator LS;
-    for (const ArchSpec &arch : GetSupportedArchitectures()) {
+    ArchSpec process_host_arch;
+    for (const ArchSpec &arch : GetSupportedArchitectures(process_host_arch)) {
       resolved_module_spec.GetArchitecture() = arch;
       error = ModuleList::GetSharedModule(resolved_module_spec, exe_module_sp,
                                           nullptr, nullptr, nullptr);

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteMacOSX.cpp

@@ -125,7 +125,8 @@ PlatformSP PlatformRemoteMacOSX::CreateInstance(bool force,
   return PlatformSP();
 }
 
-std::vector<ArchSpec> PlatformRemoteMacOSX::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformRemoteMacOSX::GetSupportedArchitectures(const ArchSpec &host_info) {
   // macOS for ARM64 support both native and translated x86_64 processes
   std::vector<ArchSpec> result;
   ARMGetSupportedArchitectures(result, llvm::Triple::MacOSX);

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteMacOSX.h

@@ -42,7 +42,8 @@ public:
                   const lldb_private::UUID *uuid_ptr,
                   lldb_private::FileSpec &local_file) override;
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
 protected:
   llvm::StringRef GetDeviceSupportDirectoryName() override;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteiOS.cpp

@@ -134,7 +134,8 @@ llvm::StringRef PlatformRemoteiOS::GetDescriptionStatic() {
 PlatformRemoteiOS::PlatformRemoteiOS()
     : PlatformRemoteDarwinDevice() {}
 
-std::vector<ArchSpec> PlatformRemoteiOS::GetSupportedArchitectures() {
+std::vector<ArchSpec> PlatformRemoteiOS::GetSupportedArchitectures(
+    const ArchSpec &process_host_arch) {
   std::vector<ArchSpec> result;
   ARMGetSupportedArchitectures(result, llvm::Triple::IOS);
   return result;

lldb/source/Plugins/Platform/MacOSX/PlatformRemoteiOS.h

@@ -39,7 +39,8 @@ public:
   // lldb_private::PluginInterface functions
   llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
 
-  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures() override;
+  std::vector<lldb_private::ArchSpec> GetSupportedArchitectures(
+      const lldb_private::ArchSpec &process_host_arch) override;
 
 protected:
   bool CheckLocalSharedCache() const override;

lldb/source/Plugins/Platform/NetBSD/PlatformNetBSD.cpp

@@ -115,9 +115,10 @@ PlatformNetBSD::PlatformNetBSD(bool is_host)
   }
 }
 
-std::vector<ArchSpec> PlatformNetBSD::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformNetBSD::GetSupportedArchitectures(const ArchSpec &process_host_arch) {
   if (m_remote_platform_sp)
-    return m_remote_platform_sp->GetSupportedArchitectures();
+    return m_remote_platform_sp->GetSupportedArchitectures(process_host_arch);
   return m_supported_architectures;
 }
 

lldb/source/Plugins/Platform/NetBSD/PlatformNetBSD.h

@@ -43,7 +43,8 @@ public:
 
   void GetStatus(Stream &strm) override;
 
-  std::vector<ArchSpec> GetSupportedArchitectures() override;
+  std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) override;
 
   uint32_t GetResumeCountForLaunchInfo(ProcessLaunchInfo &launch_info) override;
 

lldb/source/Plugins/Platform/OpenBSD/PlatformOpenBSD.cpp

@@ -118,9 +118,10 @@ PlatformOpenBSD::PlatformOpenBSD(bool is_host)
   }
 }
 
-std::vector<ArchSpec> PlatformOpenBSD::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformOpenBSD::GetSupportedArchitectures(const ArchSpec &process_host_arch) {
   if (m_remote_platform_sp)
-    return m_remote_platform_sp->GetSupportedArchitectures();
+    return m_remote_platform_sp->GetSupportedArchitectures(process_host_arch);
   return m_supported_architectures;
 }
 

lldb/source/Plugins/Platform/OpenBSD/PlatformOpenBSD.h

@@ -42,7 +42,8 @@ public:
 
   void GetStatus(Stream &strm) override;
 
-  std::vector<ArchSpec> GetSupportedArchitectures() override;
+  std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) override;
 
   bool CanDebugProcess() override;
 

lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.cpp

@@ -106,7 +106,8 @@ PlatformSP PlatformQemuUser::CreateInstance(bool force, const ArchSpec *arch) {
   return nullptr;
 }
 
-std::vector<ArchSpec> PlatformQemuUser::GetSupportedArchitectures() {
+std::vector<ArchSpec>
+PlatformQemuUser::GetSupportedArchitectures(const ArchSpec &process_host_arch) {
   llvm::Triple triple = HostInfo::GetArchitecture().GetTriple();
   triple.setEnvironment(llvm::Triple::UnknownEnvironment);
   triple.setArchName(GetGlobalProperties().GetArchitecture());

lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.h

@@ -29,7 +29,8 @@ public:
     return HostInfo::GetUserIDResolver();
   }
 
-  std::vector<ArchSpec> GetSupportedArchitectures() override;
+  std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) override;
 
   lldb::ProcessSP DebugProcess(ProcessLaunchInfo &launch_info,
                                Debugger &debugger, Target &target,

lldb/source/Plugins/Platform/Windows/PlatformWindows.h

@@ -63,7 +63,8 @@ public:
                          lldb_private::Target *target,
                          lldb_private::Status &error) override;
 
-  std::vector<ArchSpec> GetSupportedArchitectures() override {
+  std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) override {
     return m_supported_architectures;
   }
 

lldb/source/Plugins/Platform/gdb-server/PlatformRemoteGDBServer.h

@@ -65,7 +65,8 @@ public:
                                          // target, else use existing one
                          Status &error) override;
 
-  std::vector<ArchSpec> GetSupportedArchitectures() override {
+  std::vector<ArchSpec>
+  GetSupportedArchitectures(const ArchSpec &process_host_arch) override {
     return m_supported_architectures;
   }
 

lldb/source/Target/Platform.cpp

@@ -314,8 +314,9 @@ PlatformSP Platform::Create(ConstString name, Status &error) {
   return platform_sp;
 }
 
-PlatformSP Platform::Create(const ArchSpec &arch, ArchSpec *platform_arch_ptr,
+PlatformSP Platform::Create(const ArchSpec &arch,
-                            Status &error) {
+                            const ArchSpec &process_host_arch,
+                            ArchSpec *platform_arch_ptr, Status &error) {
   lldb::PlatformSP platform_sp;
   if (arch.IsValid()) {
     // Scope for locker
@@ -323,15 +324,15 @@ PlatformSP Platform::Create(const ArchSpec &arch, ArchSpec *platform_arch_ptr,
       // First try exact arch matches across all platforms already created
       std::lock_guard<std::recursive_mutex> guard(GetPlatformListMutex());
       for (const auto &platform_sp : GetPlatformList()) {
-        if (platform_sp->IsCompatibleArchitecture(arch, true,
+        if (platform_sp->IsCompatibleArchitecture(arch, process_host_arch, true,
                                                   platform_arch_ptr))
           return platform_sp;
       }
 
       // Next try compatible arch matches across all platforms already created
       for (const auto &platform_sp : GetPlatformList()) {
-        if (platform_sp->IsCompatibleArchitecture(arch, false,
+        if (platform_sp->IsCompatibleArchitecture(arch, process_host_arch,
-                                                  platform_arch_ptr))
+                                                  false, platform_arch_ptr))
           return platform_sp;
       }
     }
@@ -345,7 +346,7 @@ PlatformSP Platform::Create(const ArchSpec &arch, ArchSpec *platform_arch_ptr,
       if (create_callback) {
         platform_sp = create_callback(false, &arch);
         if (platform_sp &&
-            platform_sp->IsCompatibleArchitecture(arch, true,
+            platform_sp->IsCompatibleArchitecture(arch, process_host_arch, true,
                                                   platform_arch_ptr)) {
           std::lock_guard<std::recursive_mutex> guard(GetPlatformListMutex());
           GetPlatformList().push_back(platform_sp);
@@ -360,8 +361,8 @@ PlatformSP Platform::Create(const ArchSpec &arch, ArchSpec *platform_arch_ptr,
       if (create_callback) {
         platform_sp = create_callback(false, &arch);
         if (platform_sp &&
-            platform_sp->IsCompatibleArchitecture(arch, false,
+            platform_sp->IsCompatibleArchitecture(arch, process_host_arch,
-                                                  platform_arch_ptr)) {
+                                                  false, platform_arch_ptr)) {
           std::lock_guard<std::recursive_mutex> guard(GetPlatformListMutex());
           GetPlatformList().push_back(platform_sp);
           return platform_sp;
@@ -845,7 +846,9 @@ Platform::ResolveExecutable(const ModuleSpec &module_spec,
       // architectures that we should be using (in the correct order) and see
       // if we can find a match that way
       ModuleSpec arch_module_spec(module_spec);
-      for (const ArchSpec &arch : GetSupportedArchitectures()) {
+      ArchSpec process_host_arch;
+      for (const ArchSpec &arch :
+           GetSupportedArchitectures(process_host_arch)) {
         arch_module_spec.GetArchitecture() = arch;
         error = ModuleList::GetSharedModule(arch_module_spec, exe_module_sp,
                                             module_search_paths_ptr, nullptr,
@@ -892,7 +895,8 @@ Platform::ResolveRemoteExecutable(const ModuleSpec &module_spec,
     // correct order) and see if we can find a match that way
     StreamString arch_names;
     llvm::ListSeparator LS;
-    for (const ArchSpec &arch : GetSupportedArchitectures()) {
+    ArchSpec process_host_arch;
+    for (const ArchSpec &arch : GetSupportedArchitectures(process_host_arch)) {
       resolved_module_spec.GetArchitecture() = arch;
       error = ModuleList::GetSharedModule(resolved_module_spec, exe_module_sp,
                                           module_search_paths_ptr, nullptr,
@@ -990,7 +994,7 @@ ArchSpec Platform::GetAugmentedArchSpec(llvm::StringRef triple) {
 
   ArchSpec compatible_arch;
   ArchSpec raw_arch(triple);
-  if (!IsCompatibleArchitecture(raw_arch, false, &compatible_arch))
+  if (!IsCompatibleArchitecture(raw_arch, {}, false, &compatible_arch))
     return raw_arch;
 
   if (!compatible_arch.IsValid())
@@ -1202,11 +1206,13 @@ lldb::ProcessSP Platform::DebugProcess(ProcessLaunchInfo &launch_info,
 
 lldb::PlatformSP
 Platform::GetPlatformForArchitecture(const ArchSpec &arch,
+                                     const ArchSpec &process_host_arch,
                                      ArchSpec *platform_arch_ptr) {
   lldb::PlatformSP platform_sp;
   Status error;
   if (arch.IsValid())
-    platform_sp = Platform::Create(arch, platform_arch_ptr, error);
+    platform_sp =
+        Platform::Create(arch, process_host_arch, platform_arch_ptr, error);
   return platform_sp;
 }
 
@@ -1226,6 +1232,7 @@ Platform::CreateArchList(llvm::ArrayRef<llvm::Triple::ArchType> archs,
 /// Lets a platform answer if it is compatible with a given
 /// architecture and the target triple contained within.
 bool Platform::IsCompatibleArchitecture(const ArchSpec &arch,
+                                        const ArchSpec &process_host_arch,
                                         bool exact_arch_match,
                                         ArchSpec *compatible_arch_ptr) {
   // If the architecture is invalid, we must answer true...
@@ -1233,7 +1240,8 @@ bool Platform::IsCompatibleArchitecture(const ArchSpec &arch,
     ArchSpec platform_arch;
     auto match = exact_arch_match ? &ArchSpec::IsExactMatch
                                   : &ArchSpec::IsCompatibleMatch;
-    for (const ArchSpec &platform_arch : GetSupportedArchitectures()) {
+    for (const ArchSpec &platform_arch :
+         GetSupportedArchitectures(process_host_arch)) {
       if ((arch.*match)(platform_arch)) {
         if (compatible_arch_ptr)
           *compatible_arch_ptr = platform_arch;
@@ -1571,8 +1579,10 @@ Status Platform::GetRemoteSharedModule(const ModuleSpec &module_spec,
                                        bool *did_create_ptr) {
   // Get module information from a target.
   ModuleSpec resolved_module_spec;
+  ArchSpec process_host_arch;
   bool got_module_spec = false;
   if (process) {
+    process_host_arch = process->GetSystemArchitecture();
     // Try to get module information from the process
     if (process->GetModuleSpec(module_spec.GetFileSpec(),
                                module_spec.GetArchitecture(),
@@ -1590,7 +1600,7 @@ Status Platform::GetRemoteSharedModule(const ModuleSpec &module_spec,
     // architectures that we should be using (in the correct order) and see if
     // we can find a match that way
     ModuleSpec arch_module_spec(module_spec);
-    for (const ArchSpec &arch : GetSupportedArchitectures()) {
+    for (const ArchSpec &arch : GetSupportedArchitectures(process_host_arch)) {
       arch_module_spec.GetArchitecture() = arch;
       error = ModuleList::GetSharedModule(arch_module_spec, module_sp, nullptr,
                                           nullptr, nullptr);

lldb/source/Target/Process.cpp

@@ -2885,13 +2885,15 @@ void Process::CompleteAttach() {
   // switch architectures.
   PlatformSP platform_sp(GetTarget().GetPlatform());
   assert(platform_sp);
+  ArchSpec process_host_arch = GetSystemArchitecture();
   if (platform_sp) {
     const ArchSpec &target_arch = GetTarget().GetArchitecture();
     if (target_arch.IsValid() &&
-        !platform_sp->IsCompatibleArchitecture(target_arch, false, nullptr)) {
+        !platform_sp->IsCompatibleArchitecture(target_arch, process_host_arch,
+                                               false, nullptr)) {
       ArchSpec platform_arch;
-      platform_sp =
+      platform_sp = platform_sp->GetPlatformForArchitecture(
-          platform_sp->GetPlatformForArchitecture(target_arch, &platform_arch);
+          target_arch, process_host_arch, &platform_arch);
       if (platform_sp) {
         GetTarget().SetPlatform(platform_sp);
         GetTarget().SetArchitecture(platform_arch);

lldb/source/Target/RemoteAwarePlatform.cpp

@@ -132,7 +132,9 @@ Status RemoteAwarePlatform::ResolveExecutable(
       // if we can find a match that way
       StreamString arch_names;
       llvm::ListSeparator LS;
-      for (const ArchSpec &arch : GetSupportedArchitectures()) {
+      ArchSpec process_host_arch;
+      for (const ArchSpec &arch :
+           GetSupportedArchitectures(process_host_arch)) {
         resolved_module_spec.GetArchitecture() = arch;
         error = ModuleList::GetSharedModule(resolved_module_spec, exe_module_sp,
                                             module_search_paths_ptr, nullptr, nullptr);

lldb/source/Target/Target.cpp

@@ -1470,10 +1470,10 @@ bool Target::SetArchitecture(const ArchSpec &arch_spec, bool set_platform) {
     if (other.IsValid()) {
       auto platform_sp = GetPlatform();
       if (!platform_sp ||
-          !platform_sp->IsCompatibleArchitecture(other, false, nullptr)) {
+          !platform_sp->IsCompatibleArchitecture(other, {}, false, nullptr)) {
         ArchSpec platform_arch;
         auto arch_platform_sp =
-            Platform::GetPlatformForArchitecture(other, &platform_arch);
+            Platform::GetPlatformForArchitecture(other, {}, &platform_arch);
         if (arch_platform_sp) {
           SetPlatform(arch_platform_sp);
           if (platform_arch.IsValid())

lldb/source/Target/TargetList.cpp

@@ -180,7 +180,7 @@ Status TargetList::CreateTargetInternal(
             // the selected platform otherwise.
             if (platform_sp) {
               if (platform_sp->IsCompatibleArchitecture(
-                      module_spec.GetArchitecture(), false, nullptr)) {
+                      module_spec.GetArchitecture(), {}, false, nullptr)) {
                 platforms.push_back(platform_sp);
                 continue;
               }
@@ -192,7 +192,7 @@ Status TargetList::CreateTargetInternal(
                 (!platform_sp ||
                  host_platform_sp->GetName() != platform_sp->GetName())) {
               if (host_platform_sp->IsCompatibleArchitecture(
-                      module_spec.GetArchitecture(), false, nullptr)) {
+                      module_spec.GetArchitecture(), {}, false, nullptr)) {
                 platforms.push_back(host_platform_sp);
                 continue;
               }
@@ -202,7 +202,7 @@ Status TargetList::CreateTargetInternal(
             // executable file.
             PlatformSP fallback_platform_sp(
                 Platform::GetPlatformForArchitecture(
-                    module_spec.GetArchitecture(), nullptr));
+                    module_spec.GetArchitecture()));
             if (fallback_platform_sp) {
               platforms.push_back(fallback_platform_sp);
             }
@@ -257,8 +257,9 @@ Status TargetList::CreateTargetInternal(
   // If we have a valid architecture, make sure the current platform is
   // compatible with that architecture.
   if (!prefer_platform_arch && arch.IsValid()) {
-    if (!platform_sp->IsCompatibleArchitecture(arch, false, nullptr)) {
+    if (!platform_sp->IsCompatibleArchitecture(arch, {}, false, nullptr)) {
-      platform_sp = Platform::GetPlatformForArchitecture(arch, &platform_arch);
+      platform_sp =
+          Platform::GetPlatformForArchitecture(arch, {}, &platform_arch);
       if (platform_sp)
         debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
     }
@@ -266,8 +267,9 @@ Status TargetList::CreateTargetInternal(
     // If "arch" isn't valid, yet "platform_arch" is, it means we have an
     // executable file with a single architecture which should be used.
     ArchSpec fixed_platform_arch;
-    if (!platform_sp->IsCompatibleArchitecture(platform_arch, false, nullptr)) {
+    if (!platform_sp->IsCompatibleArchitecture(platform_arch, {}, false,
-      platform_sp = Platform::GetPlatformForArchitecture(platform_arch,
+                                               nullptr)) {
+      platform_sp = Platform::GetPlatformForArchitecture(platform_arch, {},
                                                          &fixed_platform_arch);
       if (platform_sp)
         debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
@@ -298,8 +300,9 @@ Status TargetList::CreateTargetInternal(Debugger &debugger,
 
   if (arch.IsValid()) {
     if (!platform_sp ||
-        !platform_sp->IsCompatibleArchitecture(arch, false, nullptr))
+        !platform_sp->IsCompatibleArchitecture(arch, {}, false, nullptr))
-      platform_sp = Platform::GetPlatformForArchitecture(specified_arch, &arch);
+      platform_sp =
+          Platform::GetPlatformForArchitecture(specified_arch, {}, &arch);
   }
 
   if (!platform_sp)

lldb/unittests/Platform/PlatformAppleSimulatorTest.cpp

@@ -30,7 +30,7 @@ static void testSimPlatformArchHasSimEnvironment(llvm::StringRef name) {
   ASSERT_TRUE(platform_sp);
   int num_arches = 0;
 
-  for (auto arch : platform_sp->GetSupportedArchitectures()) {
+  for (auto arch : platform_sp->GetSupportedArchitectures({})) {
     EXPECT_EQ(arch.GetTriple().getEnvironment(), llvm::Triple::Simulator);
     num_arches++;
   }
@@ -60,7 +60,7 @@ TEST_F(PlatformAppleSimulatorTest, TestHostPlatformToSim) {
     arch.GetTriple().setEnvironment(llvm::Triple::Simulator);
 
     Status error;
-    auto platform_sp = Platform::Create(arch, nullptr, error);
+    auto platform_sp = Platform::Create(arch, {}, nullptr, error);
     EXPECT_TRUE(platform_sp);
   }
 }

lldb/unittests/Target/RemoteAwarePlatformTest.cpp

@@ -26,7 +26,8 @@ public:
 
   MOCK_METHOD0(GetDescription, llvm::StringRef());
   MOCK_METHOD0(GetPluginName, llvm::StringRef());
-  MOCK_METHOD0(GetSupportedArchitectures, std::vector<ArchSpec>());
+  MOCK_METHOD1(GetSupportedArchitectures,
+               std::vector<ArchSpec>(const ArchSpec &process_host_arch));
   MOCK_METHOD4(Attach,
                ProcessSP(ProcessAttachInfo &, Debugger &, Target *, Status &));
   MOCK_METHOD0(CalculateTrapHandlerSymbolNames, void());
@@ -53,7 +54,8 @@ public:
 
   MOCK_METHOD0(GetDescription, llvm::StringRef());
   MOCK_METHOD0(GetPluginName, llvm::StringRef());
-  MOCK_METHOD0(GetSupportedArchitectures, std::vector<ArchSpec>());
+  MOCK_METHOD1(GetSupportedArchitectures,
+               std::vector<ArchSpec>(const ArchSpec &process_host_arch));
   MOCK_METHOD4(Attach,
                ProcessSP(ProcessAttachInfo &, Debugger &, Target *, Status &));
   MOCK_METHOD0(CalculateTrapHandlerSymbolNames, void());
@@ -73,7 +75,8 @@ TEST_F(RemoteAwarePlatformTest, TestResolveExecutabelOnClientByPlatform) {
   ModuleSP expected_executable(new Module(executable_spec));
 
   RemoteAwarePlatformTester platform(false);
-  EXPECT_CALL(platform, GetSupportedArchitectures())
+  static const ArchSpec process_host_arch;
+  EXPECT_CALL(platform, GetSupportedArchitectures(process_host_arch))
       .WillRepeatedly(Return(std::vector<ArchSpec>()));
   EXPECT_CALL(platform, ResolveRemoteExecutable(_, _))
       .WillRepeatedly(Return(std::make_pair(Status(), expected_executable)));