Recommitting EH patch; this should answer most of the

review feedback.
-enable-eh is still accepted but doesn't do anything.
EH intrinsics use Dwarf EH if the target supports that,
and are handled by LowerInvoke otherwise.
The separation of the EH table and frame move data is,
I think, logically figured out, but either one still
causes full EH info to be generated (not sure how to
split the metadata correctly).
MachineModuleInfo::needsFrameInfo is no longer used and
is removed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49064 91177308-0d34-0410-b5e6-96231b3b80d8

10 files changed, 114 insertions, 104 deletions

diff --git a/include/llvm/CodeGen/MachineModuleInfo.h b/include/llvm/CodeGen/MachineModuleInfo.h
index 2cd4e23781..f798e50c43 100644
--- a/include/llvm/CodeGen/MachineModuleInfo.h
+++ b/include/llvm/CodeGen/MachineModuleInfo.h
@@ -1091,10 +1091,6 @@ public:
   ///
   bool hasDebugInfo() const { return !CompileUnits.empty(); }
   
-  /// needsFrameInfo - Returns true if we need to gather callee-saved register
-  /// move info for the frame.
-  bool needsFrameInfo() const;
-
   bool callsEHReturn() const { return CallsEHReturn; }
   void setCallsEHReturn(bool b) { CallsEHReturn = b; }
 
diff --git a/lib/CodeGen/DwarfWriter.cpp b/lib/CodeGen/DwarfWriter.cpp
index e72ff07a9d..0fa956e097 100644
--- a/lib/CodeGen/DwarfWriter.cpp
+++ b/lib/CodeGen/DwarfWriter.cpp
@@ -2777,10 +2777,22 @@ private:
   };
 
   std::vector<FunctionEHFrameInfo> EHFrames;
-    
-  /// shouldEmit - Flag to indicate if debug information should be emitted.
-  ///
-  bool shouldEmit;
+
+  /// shouldEmitTable - Per-function flag to indicate if EH tables should
+  /// be emitted.
+  bool shouldEmitTable;
+
+  /// shouldEmitMoves - Per-function flag to indicate if frame moves info
+  /// should be emitted.
+  bool shouldEmitMoves;
+
+  /// shouldEmitTableModule - Per-module flag to indicate if EH tables
+  /// should be emitted.
+  bool shouldEmitTableModule;
+
+  /// shouldEmitFrameModule - Per-module flag to indicate if frame moves 
+  /// should be emitted.
+  bool shouldEmitMovesModule;
   
   /// EmitCommonEHFrame - Emit the common eh unwind frame.
   ///
@@ -3045,9 +3057,6 @@ private:
   };
 
   void EmitExceptionTable() {
-    // Map all labels and get rid of any dead landing pads.
-    MMI->TidyLandingPads();
-
     const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
     const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
     const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
@@ -3367,7 +3376,10 @@ public:
   //
   DwarfException(std::ostream &OS, AsmPrinter *A, const TargetAsmInfo *T)
   : Dwarf(OS, A, T, "eh")
-  , shouldEmit(false)
+  , shouldEmitTable(false)
+  , shouldEmitMoves(false)
+  , shouldEmitTableModule(false)
+  , shouldEmitMovesModule(false)
   {}
   
   virtual ~DwarfException() {}
@@ -3387,48 +3399,59 @@ public:
   /// EndModule - Emit all exception information that should come after the
   /// content.
   void EndModule() {
-    if (!shouldEmit) return;
-
-    const std::vector<Function *> Personalities = MMI->getPersonalities();
-    for (unsigned i =0; i < Personalities.size(); ++i)
-      EmitCommonEHFrame(Personalities[i], i);
-
-    for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
-           E = EHFrames.end(); I != E; ++I)
-      EmitEHFrame(*I);
+    if (shouldEmitMovesModule || shouldEmitTableModule) {
+      const std::vector<Function *> Personalities = MMI->getPersonalities();
+      for (unsigned i =0; i < Personalities.size(); ++i)
+        EmitCommonEHFrame(Personalities[i], i);
+
+      for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
+             E = EHFrames.end(); I != E; ++I)
+        EmitEHFrame(*I);
+    }
   }
 
   /// BeginFunction - Gather pre-function exception information.  Assumes being 
   /// emitted immediately after the function entry point.
   void BeginFunction(MachineFunction *MF) {
     this->MF = MF;
-    
-    if (MMI &&
-        ExceptionHandling &&
-        TAI->doesSupportExceptionHandling()) {
-      shouldEmit = true;
-      // Assumes in correct section after the entry point.
-      EmitLabel("eh_func_begin", ++SubprogramCount);
+    shouldEmitTable = shouldEmitMoves = false;
+    if (TAI->doesSupportExceptionHandling()) {
+
+      // Map all labels and get rid of any dead landing pads.
+      MMI->TidyLandingPads();
+      // If any landing pads survive, we need an EH table.
+      if (MMI->getLandingPads().size())
+        shouldEmitTable = true;
+
+      // See if we need frame move info.
+      if (MMI->hasDebugInfo() || !MF->getFunction()->doesNotThrow())
+        shouldEmitMoves = true;
+
+      if (shouldEmitMoves || shouldEmitTable)
+        // Assumes in correct section after the entry point.
+        EmitLabel("eh_func_begin", ++SubprogramCount);
     }
+    shouldEmitTableModule |= shouldEmitTable;
+    shouldEmitMovesModule |= shouldEmitMoves;
   }
 
   /// EndFunction - Gather and emit post-function exception information.
   ///
   void EndFunction() {
-    if (!shouldEmit) return;
+    if (shouldEmitMoves || shouldEmitTable) {
+      EmitLabel("eh_func_end", SubprogramCount);
+      EmitExceptionTable();
 
-    EmitLabel("eh_func_end", SubprogramCount);
-    EmitExceptionTable();
-
-    // Save EH frame information
-    EHFrames.
-      push_back(FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
+      // Save EH frame information
+      EHFrames.
+        push_back(FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
                                     SubprogramCount,
                                     MMI->getPersonalityIndex(),
                                     MF->getFrameInfo()->hasCalls(),
                                     !MMI->getLandingPads().empty(),
                                     MMI->getFrameMoves(),
                                     MF->getFunction()));
+      }
   }
 };
 
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index bae7140bfb..c65a6b9a79 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -19,6 +19,7 @@
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/Collector.h"
 #include "llvm/Target/TargetOptions.h"
+#include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/Support/CommandLine.h"
 using namespace llvm;
@@ -66,7 +67,7 @@ LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
   
   PM.add(createGCLoweringPass());
 
-  if (!ExceptionHandling)
+  if (!getTargetAsmInfo()->doesSupportExceptionHandling())
     PM.add(createLowerInvokePass(getTargetLowering()));
 
   // Make sure that no unreachable blocks are instruction selected.
@@ -192,7 +193,7 @@ bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
   
   PM.add(createGCLoweringPass());
   
-  if (!ExceptionHandling)
+  if (!getTargetAsmInfo()->doesSupportExceptionHandling())
     PM.add(createLowerInvokePass(getTargetLowering()));
   
   // Make sure that no unreachable blocks are instruction selected.
diff --git a/lib/CodeGen/MachineModuleInfo.cpp b/lib/CodeGen/MachineModuleInfo.cpp
index 2446bff293..0cfcc61b78 100644
--- a/lib/CodeGen/MachineModuleInfo.cpp
+++ b/lib/CodeGen/MachineModuleInfo.cpp
@@ -1583,12 +1583,6 @@ void MachineModuleInfo::AnalyzeModule(Module &M) {
   }
 }
 
-/// needsFrameInfo - Returns true if we need to gather callee-saved register
-/// move info for the frame.
-bool MachineModuleInfo::needsFrameInfo() const {
-  return hasDebugInfo() || ExceptionHandling;
-}
-
 /// SetupCompileUnits - Set up the unique vector of compile units.
 ///
 void MachineModuleInfo::SetupCompileUnits(Module &M) {
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 80b5c046a7..f237cafd49 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2827,22 +2827,18 @@ SelectionDAGLowering::visitIntrinsicCall(CallInst &I, unsigned Intrinsic) {
   }
     
   case Intrinsic::eh_exception: {
-    if (ExceptionHandling) {
-      if (!CurMBB->isLandingPad()) {
-        // FIXME: Mark exception register as live in.  Hack for PR1508.
-        unsigned Reg = TLI.getExceptionAddressRegister();
-        if (Reg) CurMBB->addLiveIn(Reg);
-      }
-      // Insert the EXCEPTIONADDR instruction.
-      SDVTList VTs = DAG.getVTList(TLI.getPointerTy(), MVT::Other);
-      SDOperand Ops[1];
-      Ops[0] = DAG.getRoot();
-      SDOperand Op = DAG.getNode(ISD::EXCEPTIONADDR, VTs, Ops, 1);
-      setValue(&I, Op);
-      DAG.setRoot(Op.getValue(1));
-    } else {
-      setValue(&I, DAG.getConstant(0, TLI.getPointerTy()));
+    if (!CurMBB->isLandingPad()) {
+      // FIXME: Mark exception register as live in.  Hack for PR1508.
+      unsigned Reg = TLI.getExceptionAddressRegister();
+      if (Reg) CurMBB->addLiveIn(Reg);
     }
+    // Insert the EXCEPTIONADDR instruction.
+    SDVTList VTs = DAG.getVTList(TLI.getPointerTy(), MVT::Other);
+    SDOperand Ops[1];
+    Ops[0] = DAG.getRoot();
+    SDOperand Op = DAG.getNode(ISD::EXCEPTIONADDR, VTs, Ops, 1);
+    setValue(&I, Op);
+    DAG.setRoot(Op.getValue(1));
     return 0;
   }
 
@@ -2852,7 +2848,7 @@ SelectionDAGLowering::visitIntrinsicCall(CallInst &I, unsigned Intrinsic) {
     MVT::ValueType VT = (Intrinsic == Intrinsic::eh_selector_i32 ?
                          MVT::i32 : MVT::i64);
     
-    if (ExceptionHandling && MMI) {
+    if (MMI) {
       if (CurMBB->isLandingPad())
         addCatchInfo(I, MMI, CurMBB);
       else {
@@ -2902,7 +2898,7 @@ SelectionDAGLowering::visitIntrinsicCall(CallInst &I, unsigned Intrinsic) {
   case Intrinsic::eh_return: {
     MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
 
-    if (MMI && ExceptionHandling) {
+    if (MMI) {
       MMI->setCallsEHReturn(true);
       DAG.setRoot(DAG.getNode(ISD::EH_RETURN,
                               MVT::Other,
@@ -2925,32 +2921,27 @@ SelectionDAGLowering::visitIntrinsicCall(CallInst &I, unsigned Intrinsic) {
    }
 
    case Intrinsic::eh_dwarf_cfa: {
-     if (ExceptionHandling) {
-       MVT::ValueType VT = getValue(I.getOperand(1)).getValueType();
-       SDOperand CfaArg;
-       if (MVT::getSizeInBits(VT) > MVT::getSizeInBits(TLI.getPointerTy()))
-         CfaArg = DAG.getNode(ISD::TRUNCATE,
-                              TLI.getPointerTy(), getValue(I.getOperand(1)));
-       else
-         CfaArg = DAG.getNode(ISD::SIGN_EXTEND,
-                              TLI.getPointerTy(), getValue(I.getOperand(1)));
-       
-       SDOperand Offset = DAG.getNode(ISD::ADD,
-                                      TLI.getPointerTy(),
-                                      DAG.getNode(ISD::FRAME_TO_ARGS_OFFSET,
-                                                  TLI.getPointerTy()),
-                                      CfaArg);
-       setValue(&I, DAG.getNode(ISD::ADD,
-                                TLI.getPointerTy(),
-                                DAG.getNode(ISD::FRAMEADDR,
-                                            TLI.getPointerTy(),
-                                            DAG.getConstant(0,
-                                                            TLI.getPointerTy())),
-                                Offset));
-     } else {
-       setValue(&I, DAG.getConstant(0, TLI.getPointerTy()));
-     }
-
+     MVT::ValueType VT = getValue(I.getOperand(1)).getValueType();
+     SDOperand CfaArg;
+     if (MVT::getSizeInBits(VT) > MVT::getSizeInBits(TLI.getPointerTy()))
+       CfaArg = DAG.getNode(ISD::TRUNCATE,
+                            TLI.getPointerTy(), getValue(I.getOperand(1)));
+     else
+       CfaArg = DAG.getNode(ISD::SIGN_EXTEND,
+                            TLI.getPointerTy(), getValue(I.getOperand(1)));
+
+     SDOperand Offset = DAG.getNode(ISD::ADD,
+                                    TLI.getPointerTy(),
+                                    DAG.getNode(ISD::FRAME_TO_ARGS_OFFSET,
+                                                TLI.getPointerTy()),
+                                    CfaArg);
+     setValue(&I, DAG.getNode(ISD::ADD,
+                              TLI.getPointerTy(),
+                              DAG.getNode(ISD::FRAMEADDR,
+                                          TLI.getPointerTy(),
+                                          DAG.getConstant(0,
+                                                          TLI.getPointerTy())),
+                              Offset));
      return 0;
   }
 
@@ -3176,7 +3167,7 @@ void SelectionDAGLowering::LowerCallTo(CallSite CS, SDOperand Callee,
     Args.push_back(Entry);
   }
 
-  if (LandingPad && ExceptionHandling && MMI) {
+  if (LandingPad && MMI) {
     // Insert a label before the invoke call to mark the try range.  This can be
     // used to detect deletion of the invoke via the MachineModuleInfo.
     BeginLabel = MMI->NextLabelID();
@@ -3195,7 +3186,7 @@ void SelectionDAGLowering::LowerCallTo(CallSite CS, SDOperand Callee,
     setValue(CS.getInstruction(), Result.first);
   DAG.setRoot(Result.second);
 
-  if (LandingPad && ExceptionHandling && MMI) {
+  if (LandingPad && MMI) {
     // Insert a label at the end of the invoke call to mark the try range.  This
     // can be used to detect deletion of the invoke via the MachineModuleInfo.
     EndLabel = MMI->NextLabelID();
@@ -4614,11 +4605,10 @@ bool SelectionDAGISel::runOnFunction(Function &Fn) {
 
   FunctionLoweringInfo FuncInfo(TLI, Fn, MF);
 
-  if (ExceptionHandling)
-    for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
-      if (InvokeInst *Invoke = dyn_cast<InvokeInst>(I->getTerminator()))
-        // Mark landing pad.
-        FuncInfo.MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
+  for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
+    if (InvokeInst *Invoke = dyn_cast<InvokeInst>(I->getTerminator()))
+      // Mark landing pad.
+      FuncInfo.MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
 
   for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
     SelectBasicBlock(I, MF, FuncInfo);
@@ -4757,7 +4747,7 @@ void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB,
 
   MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
 
-  if (ExceptionHandling && MMI && BB->isLandingPad()) {
+  if (MMI && BB->isLandingPad()) {
     // Add a label to mark the beginning of the landing pad.  Deletion of the
     // landing pad can thus be detected via the MachineModuleInfo.
     unsigned LabelID = MMI->addLandingPad(BB);
diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 2537d67dda..4cc9d2a9bd 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -1086,8 +1086,9 @@ bool DarwinAsmPrinter::doFinalization(Module &M) {
 
   O << "\n";
 
-  if (ExceptionHandling && TAI->doesSupportExceptionHandling() && MMI) {
+  if (TAI->doesSupportExceptionHandling() && MMI) {
     // Add the (possibly multiple) personalities to the set of global values.
+    // Only referenced functions get into the Personalities list.
     const std::vector<Function *>& Personalities = MMI->getPersonalities();
 
     for (std::vector<Function *>::const_iterator I = Personalities.begin(),
diff --git a/lib/Target/PowerPC/PPCRegisterInfo.cpp b/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 0e6bc69023..3bafccde8d 100644
--- a/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -20,6 +20,7 @@
 #include "PPCFrameInfo.h"
 #include "PPCSubtarget.h"
 #include "llvm/Constants.h"
+#include "llvm/Function.h"
 #include "llvm/Type.h"
 #include "llvm/CodeGen/ValueTypes.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
@@ -946,6 +947,8 @@ PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {
   MachineBasicBlock::iterator MBBI = MBB.begin();
   MachineFrameInfo *MFI = MF.getFrameInfo();
   MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
+  bool needsFrameInfo = (MMI && MMI->hasDebugInfo()) ||
+       !MF.getFunction()->doesNotThrow();
   
   // Prepare for frame info.
   unsigned FrameLabelId = 0;
@@ -1019,7 +1022,7 @@ PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {
   unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
   unsigned MaxAlign = MFI->getMaxAlignment();
 
-  if (MMI && MMI->needsFrameInfo()) {
+  if (needsFrameInfo) {
     // Mark effective beginning of when frame pointer becomes valid.
     FrameLabelId = MMI->NextLabelID();
     BuildMI(MBB, MBBI, TII.get(PPC::LABEL)).addImm(FrameLabelId).addImm(0);
@@ -1095,7 +1098,7 @@ PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {
     }
   }
   
-  if (MMI && MMI->needsFrameInfo()) {
+  if (needsFrameInfo) {
     std::vector<MachineMove> &Moves = MMI->getFrameMoves();
     
     if (NegFrameSize) {
diff --git a/lib/Target/X86/X86ATTAsmPrinter.cpp b/lib/Target/X86/X86ATTAsmPrinter.cpp
index 0679656661..151bf119ca 100644
--- a/lib/Target/X86/X86ATTAsmPrinter.cpp
+++ b/lib/Target/X86/X86ATTAsmPrinter.cpp
@@ -150,8 +150,9 @@ bool X86ATTAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
        F->getLinkage() == Function::WeakLinkage))
     O << "Lllvm$workaround$fake$stub$" << CurrentFnName << ":\n";
 
-  if (TAI->doesSupportDebugInformation()) {
-    // Emit pre-function debug information.
+  if (TAI->doesSupportDebugInformation() ||
+      TAI->doesSupportExceptionHandling()) {
+    // Emit pre-function debug and/or EH information.
     DW.BeginFunction(&MF);
   }
 
diff --git a/lib/Target/X86/X86AsmPrinter.cpp b/lib/Target/X86/X86AsmPrinter.cpp
index 98e7d9c1e8..e1bc65fc5d 100644
--- a/lib/Target/X86/X86AsmPrinter.cpp
+++ b/lib/Target/X86/X86AsmPrinter.cpp
@@ -381,9 +381,9 @@ bool X86SharedAsmPrinter::doFinalization(Module &M) {
 
     O << "\n";
 
-    if (ExceptionHandling && TAI->doesSupportExceptionHandling() && MMI &&
-        !Subtarget->is64Bit()) {
+    if (TAI->doesSupportExceptionHandling() && MMI && !Subtarget->is64Bit()) {
       // Add the (possibly multiple) personalities to the set of global values.
+      // Only referenced functions get into the Personalities list.
       const std::vector<Function *>& Personalities = MMI->getPersonalities();
 
       for (std::vector<Function *>::const_iterator I = Personalities.begin(),
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 5cd2fbe35e..6c3484ecff 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -504,6 +504,7 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
   MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
   X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
   MachineBasicBlock::iterator MBBI = MBB.begin();
+  bool needsFrameInfo = (MMI && MMI->hasDebugInfo()) || !Fn->doesNotThrow();
   
   // Prepare for frame info.
   unsigned FrameLabelId = 0;
@@ -536,7 +537,7 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
       .addReg(FramePtr);
     NumBytes -= SlotSize;
 
-    if (MMI && MMI->needsFrameInfo()) {
+    if (needsFrameInfo) {
       // Mark effective beginning of when frame pointer becomes valid.
       FrameLabelId = MMI->NextLabelID();
       BuildMI(MBB, MBBI, TII.get(X86::LABEL)).addImm(FrameLabelId).addImm(0);
@@ -548,7 +549,7 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
   }
   
   unsigned ReadyLabelId = 0;
-  if (MMI && MMI->needsFrameInfo()) {
+  if (needsFrameInfo) {
     // Mark effective beginning of when frame pointer is ready.
     ReadyLabelId = MMI->NextLabelID();
     BuildMI(MBB, MBBI, TII.get(X86::LABEL)).addImm(ReadyLabelId).addImm(0);
@@ -607,7 +608,7 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
     }
   }
 
-  if (MMI && MMI->needsFrameInfo()) {
+  if (needsFrameInfo) {
     std::vector<MachineMove> &Moves = MMI->getFrameMoves();
     const TargetData *TD = MF.getTarget().getTargetData();