1 files changed, 39 insertions, 0 deletions
diff --git a/lib/Analysis/LibCallSemantics.cpp b/lib/Analysis/LibCallSemantics.cpp
index 23639e7..cf752dd 100644
--- a/lib/Analysis/LibCallSemantics.cpp
+++ b/lib/Analysis/LibCallSemantics.cpp
@@ -15,6 +15,7 @@
 
 #include "llvm/Analysis/LibCallSemantics.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/Function.h"
 using namespace llvm;
 
@@ -61,3 +62,41 @@ LibCallInfo::getFunctionInfo(const Function *F) const {
   return Map->lookup(F->getName());
 }
 
+/// See if the given exception handling personality function is one that we
+/// understand.  If so, return a description of it; otherwise return Unknown.
+EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
+  const Function *F = dyn_cast<Function>(Pers->stripPointerCasts());
+  if (!F)
+    return EHPersonality::Unknown;
+  return StringSwitch<EHPersonality>(F->getName())
+    .Case("__gnat_eh_personality", EHPersonality::GNU_Ada)
+    .Case("__gxx_personality_v0",  EHPersonality::GNU_CXX)
+    .Case("__gcc_personality_v0",  EHPersonality::GNU_C)
+    .Case("__objc_personality_v0", EHPersonality::GNU_ObjC)
+    .Case("__except_handler3",     EHPersonality::MSVC_X86SEH)
+    .Case("__except_handler4",     EHPersonality::MSVC_X86SEH)
+    .Case("__C_specific_handler",  EHPersonality::MSVC_Win64SEH)
+    .Case("__CxxFrameHandler3",    EHPersonality::MSVC_CXX)
+    .Default(EHPersonality::Unknown);
+}
+
+bool llvm::isAsynchronousEHPersonality(EHPersonality Pers) {
+  // The two SEH personality functions can catch asynch exceptions. We assume
+  // unknown personalities don't catch asynch exceptions.
+  switch (Pers) {
+  case EHPersonality::MSVC_X86SEH:
+  case EHPersonality::MSVC_Win64SEH:
+    return true;
+  default: return false;
+  }
+  llvm_unreachable("invalid enum");
+}
+
+bool llvm::canSimplifyInvokeNoUnwind(const InvokeInst *II) {
+  const LandingPadInst *LP = II->getLandingPadInst();
+  EHPersonality Personality = classifyEHPersonality(LP->getPersonalityFn());
+  // We can't simplify any invokes to nounwind functions if the personality
+  // function wants to catch asynch exceptions.  The nounwind attribute only
+  // implies that the function does not throw synchronous exceptions.
+  return !isAsynchronousEHPersonality(Personality);
+}