Revert "Revert "Revert r248959, "[WinEH] Emit int3 after noreturn calls on Win64"""
This reverts commit r249794.
Apparently my checkouts are full of unexpected surprises today.
llvm-svn: 249796
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index d318244..2e869eb 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -110,6 +110,13 @@
OL),
TLOF(createTLOF(getTargetTriple())),
Subtarget(TT, CPU, FS, *this, Options.StackAlignmentOverride) {
+ // Windows stack unwinder gets confused when execution flow "falls through"
+ // after a call to 'noreturn' function.
+ // To prevent that, we emit a trap for 'unreachable' IR instructions.
+ // (which on X86, happens to be the 'ud2' instruction)
+ if (Subtarget.isTargetWin64())
+ this->Options.TrapUnreachable = true;
+
// By default (and when -ffast-math is on), enable estimate codegen for
// everything except scalar division. By default, use 1 refinement step for
// all operations. Defaults may be overridden by using command-line options.