[SEH] Reimplement x64 SEH using WinEHPrepare

This now emits simple, unoptimized xdata tables for __C_specific_handler
based on the handlers listed in @llvm.eh.actions calls produced by
WinEHPrepare.

This adds support for running __finally blocks when exceptions are
thrown, and removes the old landingpad fan-in codepath.

I ran some manual execution tests on small basic test cases with and
without optimization, as well as on Chrome base_unittests, which uses a
small amount of SEH.  I'm sure there are bugs, and we may need to
revert.

llvm-svn: 235154

1 files changed, 16 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/MachineModuleInfo.cpp b/llvm/lib/CodeGen/MachineModuleInfo.cpp
index e8bd1f8..2352692a 100644
--- a/llvm/lib/CodeGen/MachineModuleInfo.cpp
+++ b/llvm/lib/CodeGen/MachineModuleInfo.cpp
@@ -461,12 +461,23 @@ void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
   LP.TypeIds.push_back(0);
 }
 
-MCSymbol *
-MachineModuleInfo::addClauseForLandingPad(MachineBasicBlock *LandingPad) {
-  MCSymbol *ClauseLabel = Context.CreateTempSymbol();
+void MachineModuleInfo::addSEHCatchHandler(MachineBasicBlock *LandingPad,
+                                           const Function *Filter,
+                                           const BlockAddress *RecoverBA) {
   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
-  LP.ClauseLabels.push_back(ClauseLabel);
-  return ClauseLabel;
+  SEHHandler Handler;
+  Handler.FilterOrFinally = Filter;
+  Handler.RecoverBA = RecoverBA;
+  LP.SEHHandlers.push_back(Handler);
+}
+
+void MachineModuleInfo::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
+                                             const Function *Cleanup) {
+  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
+  SEHHandler Handler;
+  Handler.FilterOrFinally = Cleanup;
+  Handler.RecoverBA = nullptr;
+  LP.SEHHandlers.push_back(Handler);
 }
 
 /// TidyLandingPads - Remap landing pad labels and remove any deleted landing