[lldb] Move UnixSignals creation into Platform plugins

The high level goal of this change is to remove lldbTarget's dependency
on lldbPluginProcessUtility. The reason for this existing dependency is
so that we can create the appropriate UnixSignals object based on an
ArchSpec. Instead of using the ArchSpec, we can instead take advantage
of the Platform associated with the current Target.

This is accomplished by adding a new method to Platform,
CreateUnixSignals, which will create the correct UnixSignals object for
us. We then can use `Platform::GetUnixSignals` and rely on that to give
us the correct signals as needed.

Differential Revision: https://reviews.llvm.org/D146263

1 files changed, 18 insertions, 19 deletions

diff --git a/lldb/source/Target/UnixSignals.cpp b/lldb/source/Target/UnixSignals.cpp
index d754537..7c643c0 100644
--- a/lldb/source/Target/UnixSignals.cpp
+++ b/lldb/source/Target/UnixSignals.cpp
@@ -7,10 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Target/UnixSignals.h"
-#include "Plugins/Process/Utility/FreeBSDSignals.h"
-#include "Plugins/Process/Utility/LinuxSignals.h"
-#include "Plugins/Process/Utility/NetBSDSignals.h"
 #include "lldb/Host/HostInfo.h"
+#include "lldb/Target/Platform.h"
 #include "lldb/Utility/ArchSpec.h"
 #include <optional>
 #include <sstream>
@@ -30,24 +28,25 @@ UnixSignals::Signal::Signal(const char *name, bool default_suppress,
     m_description.assign(description);
 }
 
-lldb::UnixSignalsSP UnixSignals::Create(const ArchSpec &arch) {
-  const auto &triple = arch.GetTriple();
-  switch (triple.getOS()) {
-  case llvm::Triple::Linux:
-    return std::make_shared<LinuxSignals>();
-  case llvm::Triple::FreeBSD:
-  case llvm::Triple::OpenBSD:
-    return std::make_shared<FreeBSDSignals>();
-  case llvm::Triple::NetBSD:
-    return std::make_shared<NetBSDSignals>();
-  default:
-    return std::make_shared<UnixSignals>();
+lldb::UnixSignalsSP UnixSignals::CreateForHost() {
+  static lldb::UnixSignalsSP s_unix_signals_sp;
+  if (s_unix_signals_sp)
+    return s_unix_signals_sp;
+
+  auto host_platform_sp = Platform::GetHostPlatform();
+
+  // If we have no host platform, be resilient and use default UnixSignals.
+  if (!host_platform_sp)
+    s_unix_signals_sp = std::make_shared<UnixSignals>();
+  else {
+    s_unix_signals_sp = host_platform_sp->CreateUnixSignals();
+    // If the Host platform cannot create a UnixSignals object, fall back to the
+    // default UnixSignals. This may happen on platforms without a
+    // UnixSignals implementation (e.g. Windows).
+    if (!s_unix_signals_sp)
+      s_unix_signals_sp = std::make_shared<UnixSignals>();
   }
-}
 
-lldb::UnixSignalsSP UnixSignals::CreateForHost() {
-  static lldb::UnixSignalsSP s_unix_signals_sp =
-      Create(HostInfo::GetArchitecture());
   return s_unix_signals_sp;
 }