Move EH personality type classification to Analysis/LibCallSemantics.h

[rnk]

Summary

Also add enum types for __C_specific_handler and _CxxFrameHandler3 for
which we know a few things.

[majnemer]

LGTM

llvm/trunk/include/llvm/Analysis/LibCallSemantics.h

public:
     }
     
     /// getFunctionInfoArray - Return an array of descriptors that describe the
     /// set of libcalls represented by this LibCallInfo object.  This array is
     /// terminated by an entry with a NULL name.
     virtual const LibCallFunctionInfo *getFunctionInfoArray() const = 0;
   };
 
+  enum class EHPersonality {
+    Unknown,
+    GNU_Ada,
+    GNU_C,
+    GNU_CXX,
+    GNU_ObjC,
+    MSVC_Win64SEH,
+    MSVC_CXX,
+  };
+
+  /// ClassifyEHPersonality - See if the given exception handling personality
+  /// function is one that we understand.  If so, return a description of it;
+  /// otherwise return Unknown_Personality.
+  EHPersonality ClassifyEHPersonality(Value *Pers);
+
 } // end namespace llvm
 
 #endif

llvm/trunk/lib/Analysis/LibCallSemantics.cpp

 // This file implements interfaces that can be used to describe language
 // specific runtime library interfaces (e.g. libc, libm, etc) to LLVM
 // optimizers.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/LibCallSemantics.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/Function.h"
 using namespace llvm;
 
 /// This impl pointer in ~LibCallInfo is actually a StringMap.  This
 /// helper does the cast.
 static StringMap<const LibCallFunctionInfo*> *getMap(void *Ptr) {
   return static_cast<StringMap<const LibCallFunctionInfo*> *>(Ptr);
 }
if (!Map) {
     for (unsigned i = 0; Array[i].Name; ++i)
       (*Map)[Array[i].Name] = Array+i;
   }
   
   // Look up this function in the string map.
   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(Value *Pers) {
+  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("__C_specific_handler",  EHPersonality::MSVC_Win64SEH)
+    .Case("__CxxFrameHandler3",    EHPersonality::MSVC_CXX)
+    .Default(EHPersonality::Unknown);
+}

llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp

 #include "llvm-c/Initialization.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/LibCallSemantics.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/MemoryBuiltins.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/GetElementPtrTypeIterator.h"
Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) {
   // the value inserted, if appropriate. Similarly for extracts from single-use
   // loads: extract (extract (load)) will be translated to extract (load (gep))
   // and if again single-use then via load (gep (gep)) to load (gep).
   // However, double extracts from e.g. function arguments or return values
   // aren't handled yet.
   return nullptr;
 }
 
-enum Personality_Type {
-  Unknown_Personality,
-  GNU_Ada_Personality,
-  GNU_CXX_Personality,
-  GNU_ObjC_Personality
-};
-
-/// RecognizePersonality - See if the given exception handling personality
-/// function is one that we understand.  If so, return a description of it;
-/// otherwise return Unknown_Personality.
-static Personality_Type RecognizePersonality(Value *Pers) {
-  Function *F = dyn_cast<Function>(Pers->stripPointerCasts());
-  if (!F)
-    return Unknown_Personality;
-  return StringSwitch<Personality_Type>(F->getName())
-    .Case("__gnat_eh_personality", GNU_Ada_Personality)
-    .Case("__gxx_personality_v0",  GNU_CXX_Personality)
-    .Case("__objc_personality_v0", GNU_ObjC_Personality)
-    .Default(Unknown_Personality);
-}
-
 /// isCatchAll - Return 'true' if the given typeinfo will match anything.
-static bool isCatchAll(Personality_Type Personality, Constant *TypeInfo) {
+static bool isCatchAll(EHPersonality Personality, Constant *TypeInfo) {
   switch (Personality) {
-  case Unknown_Personality:
+  case EHPersonality::GNU_C:
+    // The GCC C EH personality only exists to support cleanups, so it's not
+    // clear what the semantics of catch clauses are.
+    return false;
+  case EHPersonality::Unknown:
     return false;
-  case GNU_Ada_Personality:
+  case EHPersonality::GNU_Ada:
     // While __gnat_all_others_value will match any Ada exception, it doesn't
     // match foreign exceptions (or didn't, before gcc-4.7).
     return false;
-  case GNU_CXX_Personality:
-  case GNU_ObjC_Personality:
+  case EHPersonality::GNU_CXX:
+  case EHPersonality::GNU_ObjC:
+  case EHPersonality::MSVC_Win64SEH:
+  case EHPersonality::MSVC_CXX:
     return TypeInfo->isNullValue();
   }
-  llvm_unreachable("Unknown personality!");
+  llvm_unreachable("invalid enum");
 }
 
 static bool shorter_filter(const Value *LHS, const Value *RHS) {
   return
     cast<ArrayType>(LHS->getType())->getNumElements()
   <
     cast<ArrayType>(RHS->getType())->getNumElements();
 }
 
 Instruction *InstCombiner::visitLandingPadInst(LandingPadInst &LI) {
   // The logic here should be correct for any real-world personality function.
   // However if that turns out not to be true, the offending logic can always
   // be conditioned on the personality function, like the catch-all logic is.
-  Personality_Type Personality = RecognizePersonality(LI.getPersonalityFn());
+  EHPersonality Personality = ClassifyEHPersonality(LI.getPersonalityFn());
 
   // Simplify the list of clauses, eg by removing repeated catch clauses
   // (these are often created by inlining).
   bool MakeNewInstruction = false; // If true, recreate using the following:
   SmallVector<Constant *, 16> NewClauses; // - Clauses for the new instruction;
   bool CleanupFlag = LI.isCleanup();   // - The new instruction is a cleanup.
 
   SmallPtrSet<Value *, 16> AlreadyCaught; // Typeinfos known caught already.

llvm/trunk/test/Transforms/InstCombine/LandingPadClauses.ll

 ; RUN: opt < %s -instcombine -S | FileCheck %s
 
 @T1 = external constant i32
 @T2 = external constant i32
 @T3 = external constant i32
 
 declare i32 @generic_personality(i32, i64, i8*, i8*)
 declare i32 @__gxx_personality_v0(i32, i64, i8*, i8*)
 declare i32 @__objc_personality_v0(i32, i64, i8*, i8*)
+declare i32 @__C_specific_handler(...)
 
 declare void @bar()
 
 define void @foo_generic() {
 ; CHECK-LABEL: @foo_generic(
   invoke void @bar()
     to label %cont.a unwind label %lpad.a
 cont.a:
lpad.d:
   %d = landingpad { i8*, i32 } personality i32 (i32, i64, i8*, i8*)* @__objc_personality_v0
           cleanup
           catch i32* null
   unreachable
 ; CHECK: %d = landingpad
 ; CHECK-NEXT: null
 ; CHECK-NEXT: unreachable
 }
+
+define void @foo_seh() {
+; CHECK-LABEL: @foo_seh(
+  invoke void @bar()
+    to label %cont.a unwind label %lpad.a
+cont.a:
+  invoke void @bar()
+    to label %cont.b unwind label %lpad.b
+cont.b:
+  invoke void @bar()
+    to label %cont.c unwind label %lpad.c
+cont.c:
+  invoke void @bar()
+    to label %cont.d unwind label %lpad.d
+cont.d:
+  ret void
+
+lpad.a:
+  %a = landingpad { i8*, i32 } personality i32 (...)* @__C_specific_handler
+          catch i32* null
+          catch i32* @T1
+  unreachable
+; CHECK: %a = landingpad
+; CHECK-NEXT: null
+; CHECK-NEXT: unreachable
+
+lpad.b:
+  %b = landingpad { i8*, i32 } personality i32 (...)* @__C_specific_handler
+          filter [1 x i32*] zeroinitializer
+  unreachable
+; CHECK: %b = landingpad
+; CHECK-NEXT: cleanup
+; CHECK-NEXT: unreachable
+
+lpad.c:
+  %c = landingpad { i8*, i32 } personality i32 (...)* @__C_specific_handler
+          filter [2 x i32*] [i32* @T1, i32* null]
+  unreachable
+; CHECK: %c = landingpad
+; CHECK-NEXT: cleanup
+; CHECK-NEXT: unreachable
+
+lpad.d:
+  %d = landingpad { i8*, i32 } personality i32 (...)* @__C_specific_handler
+          cleanup
+          catch i32* null
+  unreachable
+; CHECK: %d = landingpad
+; CHECK-NEXT: null
+; CHECK-NEXT: unreachable
+}