Revert "[WinEH] Add an EH registration and state insertion pass for 32-bit x86"

This reverts commit r236359. Things are still broken despite testing. :(

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236360 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCAsmInfo.h

@@ -37,7 +37,6 @@ enum class EncodingType {
   ARM,     /// Windows NT (Windows on ARM)
   CE,      /// Windows CE ARM, PowerPC, SH3, SH4
   Itanium, /// Windows x64, Windows Itanium (IA-64)
-  X86,     /// Windows x86, uses no CFI, just EH tables
   MIPS = Alpha,
 };
 }
@@ -507,13 +506,12 @@ public:
   /// frame information to unwind.
   bool usesCFIForEH() const {
     return (ExceptionsType == ExceptionHandling::DwarfCFI ||
-            ExceptionsType == ExceptionHandling::ARM || usesWindowsCFI());
+            ExceptionsType == ExceptionHandling::ARM ||
+            ExceptionsType == ExceptionHandling::WinEH);
   }
 
   bool usesWindowsCFI() const {
-    return ExceptionsType == ExceptionHandling::WinEH &&
+    return ExceptionsType == ExceptionHandling::WinEH;
-           (WinEHEncodingType != WinEH::EncodingType::Invalid &&
-            WinEHEncodingType != WinEH::EncodingType::X86);
   }
 
   bool doesDwarfUseRelocationsAcrossSections() const {

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -266,8 +266,6 @@ bool AsmPrinter::doInitialization(Module &M) {
   case ExceptionHandling::WinEH:
     switch (MAI->getWinEHEncodingType()) {
     default: llvm_unreachable("unsupported unwinding information encoding");
-    case WinEH::EncodingType::Invalid:
-      break;
     case WinEH::EncodingType::Itanium:
       ES = new Win64Exception(this);
       break;

lib/CodeGen/WinEHPrepare.cpp

@@ -8,11 +8,9 @@
 //===----------------------------------------------------------------------===//
 //
 // This pass lowers LLVM IR exception handling into something closer to what the
-// backend wants for functions using a personality function from a runtime
+// backend wants. It snifs the personality function to see which kind of
-// provided by MSVC. Functions with other personality functions are left alone
+// preparation is necessary. If the personality function uses the Itanium LSDA,
-// and may be prepared by other passes. In particular, all supported MSVC
+// this pass delegates to the DWARF EH preparation pass.
-// personality functions require cleanup code to be outlined, and the C++
-// personality requires catch handler code to be outlined.
 //
 //===----------------------------------------------------------------------===//
 
@@ -33,6 +31,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -923,7 +922,7 @@ bool WinEHPrepare::prepareExceptionHandlers(
   if (SEHExceptionCodeSlot) {
     if (SEHExceptionCodeSlot->hasNUses(0))
       SEHExceptionCodeSlot->eraseFromParent();
-    else if (isAllocaPromotable(SEHExceptionCodeSlot))
+    else
       PromoteMemToReg(SEHExceptionCodeSlot, *DT);
   }
 

lib/Target/X86/CMakeLists.txt

@@ -32,7 +32,6 @@ set(sources
   X86TargetTransformInfo.cpp
   X86VZeroUpper.cpp
   X86FixupLEAs.cpp
-  X86WinEHState.cpp
   )
 
 if( CMAKE_CL_64 )

lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp

@@ -132,9 +132,8 @@ X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
     PrivateLabelPrefix = ".L";
     PointerSize = 8;
     WinEHEncodingType = WinEH::EncodingType::Itanium;
-  }
-
     ExceptionsType = ExceptionHandling::WinEH;
+  }
 
   AssemblerDialect = AsmWriterFlavor;
 

lib/Target/X86/X86.h

@@ -69,12 +69,6 @@ FunctionPass *createX86FixupLEAs();
 /// esp-relative movs with pushes.
 FunctionPass *createX86CallFrameOptimization();
 
-/// createX86WinEHStatePass - Return an IR pass that inserts EH registration
-/// stack objects and explicit EH state updates. This pass must run after EH
-/// preparation, which does Windows-specific but architecture-neutral
-/// preparation.
-FunctionPass *createX86WinEHStatePass();
-
 } // End llvm namespace
 
 #endif

lib/Target/X86/X86TargetMachine.cpp

@@ -185,7 +185,6 @@ public:
   void addIRPasses() override;
   bool addInstSelector() override;
   bool addILPOpts() override;
-  bool addPreISel() override;
   void addPreRegAlloc() override;
   void addPostRegAlloc() override;
   void addPreEmitPass() override;
@@ -221,14 +220,6 @@ bool X86PassConfig::addILPOpts() {
   return true;
 }
 
-bool X86PassConfig::addPreISel() {
-  // Only add this pass for 32-bit x86.
-  Triple TT(TM->getTargetTriple());
-  if (TT.getArch() == Triple::x86)
-    addPass(createX86WinEHStatePass());
-  return true;
-}
-
 void X86PassConfig::addPreRegAlloc() {
   addPass(createX86CallFrameOptimization());
 }

lib/Target/X86/X86WinEHState.cpp

@@ -1,317 +0,0 @@
-//===-- X86WinEHState - Insert EH state updates for win32 exceptions ------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// All functions using an MSVC EH personality use an explicitly updated state
-// number stored in an exception registration stack object. The registration
-// object is linked into a thread-local chain of registrations stored at fs:00.
-// This pass adds the registration object and EH state updates.
-//
-//===----------------------------------------------------------------------===//
-
-#include "X86.h"
-#include "llvm/Analysis/LibCallSemantics.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/WinEHFuncInfo.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/PatternMatch.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Cloning.h"
-#include "llvm/Transforms/Utils/Local.h"
-
-using namespace llvm;
-using namespace llvm::PatternMatch;
-
-#define DEBUG_TYPE "winehstate"
-
-namespace {
-class WinEHStatePass : public FunctionPass {
-public:
-  static char ID; // Pass identification, replacement for typeid.
-
-  WinEHStatePass() : FunctionPass(ID) {}
-
-  bool runOnFunction(Function &Fn) override;
-
-  bool doInitialization(Module &M) override;
-
-  bool doFinalization(Module &M) override;
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override;
-
-  const char *getPassName() const override {
-    return "Windows 32-bit x86 EH state insertion";
-  }
-
-private:
-  void emitExceptionRegistrationRecord(Function *F);
-
-  void linkExceptionRegistration(IRBuilder<> &Builder, Value *RegNode,
-                                 Value *Handler);
-  void unlinkExceptionRegistration(IRBuilder<> &Builder, Value *RegNode);
-
-  // Module-level type getters.
-  Type *getEHRegistrationType();
-  Type *getSEH3RegistrationType();
-  Type *getSEH4RegistrationType();
-  Type *getCXXEH3RegistrationType();
-
-  // Per-module data.
-  Module *TheModule = nullptr;
-  StructType *EHRegistrationTy = nullptr;
-  StructType *CXXEH3RegistrationTy = nullptr;
-  StructType *SEH3RegistrationTy = nullptr;
-  StructType *SEH4RegistrationTy = nullptr;
-
-  // Per-function state
-  EHPersonality Personality = EHPersonality::Unknown;
-  Function *PersonalityFn = nullptr;
-};
-}
-
-FunctionPass *llvm::createX86WinEHStatePass() { return new WinEHStatePass(); }
-
-char WinEHStatePass::ID = 0;
-
-bool WinEHStatePass::doInitialization(Module &M) {
-  TheModule = &M;
-  return false;
-}
-
-bool WinEHStatePass::doFinalization(Module &M) {
-  assert(TheModule == &M);
-  TheModule = nullptr;
-  EHRegistrationTy = nullptr;
-  CXXEH3RegistrationTy = nullptr;
-  SEH3RegistrationTy = nullptr;
-  SEH4RegistrationTy = nullptr;
-  return false;
-}
-
-void WinEHStatePass::getAnalysisUsage(AnalysisUsage &AU) const {
-  // This pass should only insert a stack allocation, memory accesses, and
-  // framerecovers.
-  AU.setPreservesCFG();
-}
-
-bool WinEHStatePass::runOnFunction(Function &F) {
-  // Check the personality. Do nothing if this is not an MSVC personality.
-  LandingPadInst *LP = nullptr;
-  for (BasicBlock &BB : F) {
-    LP = BB.getLandingPadInst();
-    if (LP)
-      break;
-  }
-  if (!LP)
-    return false;
-  PersonalityFn =
-      dyn_cast<Function>(LP->getPersonalityFn()->stripPointerCasts());
-  if (!PersonalityFn)
-    return false;
-  Personality = classifyEHPersonality(PersonalityFn);
-  if (!isMSVCEHPersonality(Personality))
-    return false;
-
-  emitExceptionRegistrationRecord(&F);
-  // FIXME: State insertion.
-
-  // Reset per-function state.
-  PersonalityFn = nullptr;
-  Personality = EHPersonality::Unknown;
-  return true;
-}
-
-/// Get the common EH registration subobject:
-///   struct EHRegistrationNode {
-///     EHRegistrationNode *Next;
-///     EXCEPTION_DISPOSITION (*Handler)(...);
-///   };
-Type *WinEHStatePass::getEHRegistrationType() {
-  if (EHRegistrationTy)
-    return EHRegistrationTy;
-  LLVMContext &Context = TheModule->getContext();
-  EHRegistrationTy = StructType::create(Context, "EHRegistrationNode");
-  Type *FieldTys[] = {
-      EHRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next
-      Type::getInt8PtrTy(Context) // EXCEPTION_DISPOSITION (*Handler)(...)
-  };
-  EHRegistrationTy->setBody(FieldTys, false);
-  return EHRegistrationTy;
-}
-
-/// The __CxxFrameHandler3 registration node:
-///   struct CXXExceptionRegistration {
-///     void *SavedESP;
-///     EHRegistrationNode SubRecord;
-///     int32_t TryLevel;
-///   };
-Type *WinEHStatePass::getCXXEH3RegistrationType() {
-  if (CXXEH3RegistrationTy)
-    return CXXEH3RegistrationTy;
-  LLVMContext &Context = TheModule->getContext();
-  Type *FieldTys[] = {
-      Type::getInt8PtrTy(Context), // void *SavedESP
-      getEHRegistrationType(),     // EHRegistrationNode SubRecord
-      Type::getInt32Ty(Context)    // int32_t TryLevel
-  };
-  CXXEH3RegistrationTy =
-      StructType::create(FieldTys, "CXXExceptionRegistration");
-  return CXXEH3RegistrationTy;
-}
-
-/// The _except_handler3 registration node:
-///   struct EH3ExceptionRegistration {
-///     EHRegistrationNode SubRecord;
-///     void *ScopeTable;
-///     int32_t TryLevel;
-///   };
-Type *WinEHStatePass::getSEH3RegistrationType() {
-  if (SEH3RegistrationTy)
-    return SEH3RegistrationTy;
-  LLVMContext &Context = TheModule->getContext();
-  Type *FieldTys[] = {
-      getEHRegistrationType(),     // EHRegistrationNode SubRecord
-      Type::getInt8PtrTy(Context), // void *ScopeTable
-      Type::getInt32Ty(Context)    // int32_t TryLevel
-  };
-  SEH3RegistrationTy = StructType::create(FieldTys, "EH3ExceptionRegistration");
-  return SEH3RegistrationTy;
-}
-
-/// The _except_handler4 registration node:
-///   struct EH4ExceptionRegistration {
-///     void *SavedESP;
-///     _EXCEPTION_POINTERS *ExceptionPointers;
-///     EHRegistrationNode SubRecord;
-///     int32_t EncodedScopeTable;
-///     int32_t TryLevel;
-///   };
-Type *WinEHStatePass::getSEH4RegistrationType() {
-  if (SEH4RegistrationTy)
-    return SEH4RegistrationTy;
-  LLVMContext &Context = TheModule->getContext();
-  Type *FieldTys[] = {
-      Type::getInt8PtrTy(Context), // void *SavedESP
-      Type::getInt8PtrTy(Context), // void *ExceptionPointers
-      getEHRegistrationType(),     // EHRegistrationNode SubRecord
-      Type::getInt32Ty(Context),   // int32_t EncodedScopeTable
-      Type::getInt32Ty(Context)    // int32_t TryLevel
-  };
-  SEH4RegistrationTy = StructType::create(FieldTys, "EH4ExceptionRegistration");
-  return SEH4RegistrationTy;
-}
-
-// Emit an exception registration record. These are stack allocations with the
-// common subobject of two pointers: the previous registration record (the old
-// fs:00) and the personality function for the current frame. The data before
-// and after that is personality function specific.
-void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) {
-  assert(Personality == EHPersonality::MSVC_CXX ||
-         Personality == EHPersonality::MSVC_X86SEH);
-
-  StringRef PersonalityName = PersonalityFn->getName();
-  IRBuilder<> Builder(&F->getEntryBlock(), F->getEntryBlock().begin());
-  Type *Int8PtrType = Builder.getInt8PtrTy();
-  Value *SubRecord = nullptr;
-  if (PersonalityName == "__CxxFrameHandler3") {
-    Type *RegNodeTy = getCXXEH3RegistrationType();
-    Value *RegNode = Builder.CreateAlloca(RegNodeTy);
-    // FIXME: We can skip this in -GS- mode, when we figure that out.
-    // SavedESP = llvm.stacksave()
-    Value *SP = Builder.CreateCall(
-        Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave));
-    Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
-    // TryLevel = -1
-    Builder.CreateStore(Builder.getInt32(-1),
-                        Builder.CreateStructGEP(RegNodeTy, RegNode, 2));
-    // FIXME: 'Personality' is incorrect here. We need to generate a trampoline
-    // that effectively gets the LSDA.
-    SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 1);
-    linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
-  } else if (PersonalityName == "_except_handler3") {
-    Type *RegNodeTy = getSEH3RegistrationType();
-    Value *RegNode = Builder.CreateAlloca(RegNodeTy);
-    // TryLevel = -1
-    Builder.CreateStore(Builder.getInt32(-1),
-                        Builder.CreateStructGEP(RegNodeTy, RegNode, 2));
-    // FIXME: Generalize llvm.eh.sjljl.lsda for this.
-    // ScopeTable = nullptr
-    Builder.CreateStore(Constant::getNullValue(Int8PtrType),
-                        Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
-    SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 0);
-    linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
-  } else if (PersonalityName == "_except_handler4") {
-    Type *RegNodeTy = getSEH4RegistrationType();
-    Value *RegNode = Builder.CreateAlloca(RegNodeTy);
-    // SavedESP = llvm.stacksave()
-    Value *SP = Builder.CreateCall(
-        Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave));
-    Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
-    // TryLevel = -2
-    Builder.CreateStore(Builder.getInt32(-2),
-                        Builder.CreateStructGEP(RegNodeTy, RegNode, 4));
-    // FIXME: Generalize llvm.eh.sjljl.lsda for this, and then do the stack
-    // cookie xor.
-    // ScopeTable = nullptr
-    Builder.CreateStore(Builder.getInt32(0),
-                        Builder.CreateStructGEP(RegNodeTy, RegNode, 3));
-    SubRecord = Builder.CreateStructGEP(RegNodeTy, RegNode, 2);
-    linkExceptionRegistration(Builder, SubRecord, PersonalityFn);
-  } else {
-    llvm_unreachable("unexpected personality function");
-  }
-
-  // FIXME: Insert an unlink before all returns.
-  for (BasicBlock &BB : *F) {
-    TerminatorInst *T = BB.getTerminator();
-    if (!isa<ReturnInst>(T))
-      continue;
-    Builder.SetInsertPoint(T);
-    unlinkExceptionRegistration(Builder, SubRecord);
-  }
-}
-
-void WinEHStatePass::linkExceptionRegistration(IRBuilder<> &Builder,
-                                               Value *RegNode, Value *Handler) {
-  Type *RegNodeTy = getEHRegistrationType();
-  // Handler = Handler
-  Handler = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy());
-  Builder.CreateStore(Handler, Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
-  // Next = [fs:00]
-  Constant *FSZero =
-      Constant::getNullValue(RegNodeTy->getPointerTo()->getPointerTo(257));
-  Value *Next = Builder.CreateLoad(FSZero);
-  Builder.CreateStore(Next, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
-  // [fs:00] = RegNode
-  Builder.CreateStore(RegNode, FSZero);
-}
-
-void WinEHStatePass::unlinkExceptionRegistration(IRBuilder<> &Builder,
-                                                 Value *RegNode) {
-  // Clone RegNode into the current BB for better address mode folding.
-  if (auto *GEP = dyn_cast<GetElementPtrInst>(RegNode)) {
-    GEP = cast<GetElementPtrInst>(GEP->clone());
-    Builder.Insert(GEP);
-    RegNode = GEP;
-  }
-  Type *RegNodeTy = getEHRegistrationType();
-  // [fs:00] = RegNode->Next
-  Value *Next =
-      Builder.CreateLoad(Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
-  Constant *FSZero =
-      Constant::getNullValue(RegNodeTy->getPointerTo()->getPointerTo(257));
-  Builder.CreateStore(Next, FSZero);
-}

test/CodeGen/X86/inalloca-invoke.ll

@@ -4,7 +4,6 @@
 
 %frame.reverse = type { %Iter, %Iter }
 
-declare i32 @pers(...)
 declare void @llvm.stackrestore(i8*)
 declare i8* @llvm.stacksave()
 declare void @begin(%Iter* sret)
@@ -23,7 +22,8 @@ blah:
 
 ; CHECK:  calll   __chkstk
 ; CHECK:  movl %esp, %[[beg:[^ ]*]]
-; CHECK:  leal 12(%[[beg]]), %[[end:[^ ]*]]
+; CHECK:  movl %esp, %[[end:[^ ]*]]
+; CHECK:  addl $12, %[[end]]
 
   call void @begin(%Iter* sret %temp.lvalue)
 ; CHECK:  calll _begin
@@ -49,7 +49,7 @@ invoke.cont5:                                     ; preds = %invoke.cont
   ret i32 0
 
 lpad:                                             ; preds = %invoke.cont, %entry
-  %lp = landingpad { i8*, i32 } personality i32 (...)* @pers
+  %lp = landingpad { i8*, i32 } personality i8* null
           cleanup
   unreachable
 }

test/CodeGen/X86/win32-eh.ll

@@ -1,77 +0,0 @@
-; RUN: llc -mtriple=i686-pc-windows-msvc < %s | FileCheck %s
-
-declare void @may_throw_or_crash()
-declare i32 @_except_handler3(...)
-declare i32 @_except_handler4(...)
-declare i32 @__CxxFrameHandler3(...)
-declare void @llvm.eh.begincatch(i8*, i8*)
-declare void @llvm.eh.endcatch()
-
-define void @use_except_handler3() {
-  invoke void @may_throw_or_crash()
-      to label %cont unwind label %catchall
-cont:
-  ret void
-catchall:
-  landingpad { i8*, i32 } personality i32 (...)* @_except_handler3
-      catch i8* null
-  br label %cont
-}
-
-; CHECK-LABEL: _use_except_handler3:
-; CHECK: subl ${{[0-9]+}}, %esp
-; CHECK: movl %fs:0, %[[next:[^ ,]*]]
-; CHECK: movl %[[next]], (%esp)
-; CHECK: leal (%esp), %[[node:[^ ,]*]]
-; CHECK: movl %[[node]], %fs:0
-; CHECK: calll _may_throw_or_crash
-; CHECK: movl (%esp), %[[next:[^ ,]*]]
-; CHECK: movl %[[next]], %fs:0
-; CHECK: retl
-
-define void @use_except_handler4() {
-  invoke void @may_throw_or_crash()
-      to label %cont unwind label %catchall
-cont:
-  ret void
-catchall:
-  landingpad { i8*, i32 } personality i32 (...)* @_except_handler4
-      catch i8* null
-  br label %cont
-}
-
-; CHECK-LABEL: _use_except_handler4:
-; CHECK: subl ${{[0-9]+}}, %esp
-; CHECK: leal 8(%esp), %[[node:[^ ,]*]]
-; CHECK: movl %fs:0, %[[next:[^ ,]*]]
-; CHECK: movl %[[next]], 8(%esp)
-; CHECK: movl %[[node]], %fs:0
-; CHECK: calll _may_throw_or_crash
-; CHECK: movl 8(%esp), %[[next:[^ ,]*]]
-; CHECK: movl %[[next]], %fs:0
-; CHECK: retl
-
-define void @use_CxxFrameHandler3() {
-  invoke void @may_throw_or_crash()
-      to label %cont unwind label %catchall
-cont:
-  ret void
-catchall:
-  %ehvals = landingpad { i8*, i32 } personality i32 (...)* @__CxxFrameHandler3
-      catch i8* null
-  %ehptr = extractvalue { i8*, i32 } %ehvals, 0
-  call void @llvm.eh.begincatch(i8* %ehptr, i8* null)
-  call void @llvm.eh.endcatch()
-  br label %cont
-}
-
-; CHECK-LABEL: _use_CxxFrameHandler3:
-; CHECK: subl ${{[0-9]+}}, %esp
-; CHECK: leal 4(%esp), %[[node:[^ ,]*]]
-; CHECK: movl %fs:0, %[[next:[^ ,]*]]
-; CHECK: movl %[[next]], 4(%esp)
-; CHECK: movl %[[node]], %fs:0
-; CHECK: calll _may_throw_or_crash
-; CHECK: movl 4(%esp), %[[next:[^ ,]*]]
-; CHECK: movl %[[next]], %fs:0
-; CHECK: retl