[WinEH] Make sure LSDA tables are 4 byte aligned

Apparently this is important, otherwise _except_handler3 assumes that
the registration node is corrupted and ignores it.

Also fix a bug in WinEHPrepare where we would insert code after a
terminator instruction.

llvm-svn: 241877

2 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
index 0294a2b7c4b..55f97e6214b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -350,6 +350,7 @@ void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
   // EHFlags & 1 -> Synchronous exceptions only, no async exceptions.
   // EHFlags & 2 -> ???
   // EHFlags & 4 -> The function is noexcept(true), unwinding can't continue.
+  OS.EmitValueToAlignment(4);
   OS.EmitLabel(FuncInfoXData);
   OS.EmitIntValue(0x19930522, 4);                      // MagicNumber
   OS.EmitIntValue(FuncInfo.UnwindMap.size(), 4);       // MaxState
@@ -578,6 +579,7 @@ void WinException::emitExceptHandlerTable(const MachineFunction *MF) {
 
   // Emit the __ehtable label that we use for llvm.x86.seh.lsda.
   MCSymbol *LSDALabel = Asm->OutContext.getOrCreateLSDASymbol(FLinkageName);
+  OS.EmitValueToAlignment(4);
   OS.EmitLabel(LSDALabel);
 
   const Function *Per = MMI->getPersonality();
diff --git a/llvm/lib/Target/X86/X86WinEHState.cpp b/llvm/lib/Target/X86/X86WinEHState.cpp
index 3a8bcaa4bb7..1bbcf704255 100644
--- a/llvm/lib/Target/X86/X86WinEHState.cpp
+++ b/llvm/lib/Target/X86/X86WinEHState.cpp
@@ -440,8 +440,10 @@ int WinEHStatePass::escapeRegNode(Function &F) {
 
   // Replace the call (if it exists) with new one. Otherwise, insert at the end
   // of the entry block.
-  IRBuilder<> Builder(&F.getEntryBlock(),
-                      EscapeCall ? EscapeCall : F.getEntryBlock().end());
+  Instruction *InsertPt = EscapeCall;
+  if (!EscapeCall)
+    InsertPt = F.getEntryBlock().getTerminator();
+  IRBuilder<> Builder(&F.getEntryBlock(), InsertPt);
   Builder.CreateCall(FrameEscape, Args);
   if (EscapeCall)
     EscapeCall->eraseFromParent();