[lldb-server] Use Platform plugin corresponding to the host

In ee23250 I moved UnixSignal
initialization from lldbTarget to the various platform plugins. This
inadvertently broke lldb-server because lldb-server doesn't use
Platform plugins. lldb-server still needs to be able to create a
UnixSignals object for the host platform so we can add the relevant
platform plugin to lldb-server to make sure we always have a
HostPlatform.

Differential Revision: https://reviews.llvm.org/D146668

lldb/test/API/functionalities/inferior-crashing/TestInferiorCrashing.py

@@ -63,7 +63,9 @@ def inferior_crashing(self):
         # The exact stop reason depends on the platform
         if self.platformIsDarwin():
             stop_reason = 'stop reason = EXC_BAD_ACCESS'
-        elif self.getPlatform() == "linux" or self.getPlatform() == "freebsd":
+        elif self.getPlatform() == "linux":
+            stop_reason = 'stop reason = signal SIGSEGV: address not mapped to object'
+        elif self.getPlatform() == "freebsd":
             stop_reason = 'stop reason = signal SIGSEGV'
         else:
             stop_reason = 'stop reason = invalid address'

lldb/tools/lldb-server/CMakeLists.txt

@@ -7,20 +7,29 @@ set(LLDB_PLUGINS)
 
 if(CMAKE_SYSTEM_NAME MATCHES "Linux|Android")
   list(APPEND LLDB_PLUGINS lldbPluginProcessLinux)
+  if (CMAKE_SYSTEM_NAME MATCHES "Linux")
+    list(APPEND LLDB_PLUGINS lldbPluginPlatformLinux)
+  else()
+    list(APPEND LLDB_PLUGINS lldbPluginPlatformAndroid)
+  endif()
 endif()
 
 if(CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
   list(APPEND LLDB_PLUGINS lldbPluginProcessFreeBSD)
+  list(APPEND LLDB_PLUGINS lldbPluginPlatformFreeBSD)
 endif()
 
 if(CMAKE_SYSTEM_NAME MATCHES "NetBSD")
   list(APPEND LLDB_PLUGINS lldbPluginProcessNetBSD)
+  list(APPEND LLDB_PLUGINS lldbPluginPlatformNetBSD)
 endif()
 
 if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
   list(APPEND LLDB_PLUGINS lldbPluginObjectFileMachO)
+  list(APPEND LLDB_PLUGINS lldbPluginPlatformMacOSX)
 elseif(CMAKE_SYSTEM_NAME MATCHES "Windows")
   list(APPEND LLDB_PLUGINS lldbPluginObjectFilePECOFF)
+  list(APPEND LLDB_PLUGINS lldbPluginPlatformWindows)
 else()
   list(APPEND LLDB_PLUGINS lldbPluginObjectFileELF)
 endif()

lldb/tools/lldb-server/SystemInitializerLLGS.cpp

@@ -11,12 +11,29 @@
 #if defined(__APPLE__)
 #include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h"
 using HostObjectFile = ObjectFileMachO;
+#include "Plugins/Platform/MacOSX/PlatformMacOSX.h"
+using HostPlatform = lldb_private::PlatformMacOSX;
 #elif defined(_WIN32)
 #include "Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h"
 using HostObjectFile = ObjectFilePECOFF;
+#include "Plugins/Platform/Windows/PlatformWindows.h"
+using HostPlatform = lldb_private::PlatformWindows;
 #else
 #include "Plugins/ObjectFile/ELF/ObjectFileELF.h"
 using HostObjectFile = ObjectFileELF;
+#if defined(__ANDROID__)
+#include "Plugins/Platform/Android/PlatformAndroid.h"
+using HostPlatform = lldb_private::platform_android::PlatformAndroid;
+#elif defined(__FreeBSD__)
+#include "Plugins/Platform/FreeBSD/PlatformFreeBSD.h"
+using HostPlatform = lldb_private::platform_freebsd::PlatformFreeBSD;
+#elif defined(__linux__)
+#include "Plugins/Platform/Linux/PlatformLinux.h"
+using HostPlatform = lldb_private::platform_linux::PlatformLinux;
+#elif defined(__NetBSD__)
+#include "Plugins/Platform/NetBSD/PlatformNetBSD.h"
+using HostPlatform = lldb_private::platform_netbsd::PlatformNetBSD;
+#endif
 #endif
 
 #if defined(__arm64__) || defined(__aarch64__) || defined(_M_ARM64)
@@ -58,6 +75,7 @@ llvm::Error SystemInitializerLLGS::Initialize() {
     return e;
 
   HostObjectFile::Initialize();
+  HostPlatform::Initialize();
 
 #if defined(LLDB_TARGET_ARM) || defined(LLDB_TARGET_ARM64)
   EmulateInstructionARM::Initialize();
@@ -80,6 +98,7 @@ llvm::Error SystemInitializerLLGS::Initialize() {
 
 void SystemInitializerLLGS::Terminate() {
   HostObjectFile::Terminate();
+  HostPlatform::Terminate();
 
 #if defined(LLDB_TARGET_ARM) || defined(LLDB_TARGET_ARM64)
   EmulateInstructionARM::Terminate();