[AArch64] [Windows] Trap after noreturn calls.

Like the comment says, this isn't the most efficient fix in terms of
codesize, but it works.

Differential Revision: https://reviews.llvm.org/D54129

llvm-svn: 346358

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
index fe2eea65ffe..5168c0c67da 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
@@ -263,6 +263,16 @@ AArch64TargetMachine::AArch64TargetMachine(const Target &T, const Triple &TT,
     this->Options.NoTrapAfterNoreturn = true;
   }
 
+  if (TT.isOSWindows()) {
+    // Unwinding can get confused if the last instruction in an
+    // exception-handling region (function, funclet, try block, etc.)
+    // is a call.
+    //
+    // FIXME: We could elide the trap if the next instruction would be in
+    // the same region anyway.
+    this->Options.TrapUnreachable = true;
+  }
+
   // Enable GlobalISel at or below EnableGlobalISelAt0.
   if (getOptLevel() <= EnableGlobalISelAtO)
     setGlobalISel(true);