Rename EH related stuff to be more precise

Summary:
The current "WinEH" exception handling type is more about Itanium-style
LSDA tables layered on top of the Windows native unwind info format
instead of .eh_frame tables or EHABI unwind info. Use the name
"ItaniumWinEH" to better reflect the hybrid nature of the design.

Also rename isExceptionHandlingDWARF to usesItaniumLSDAForExceptions,
since the LSDA is part of the Itanium C++ ABI document, and not the
DWARF standard.

Reviewers: echristo

Subscribers: llvm-commits, compnerd

Differential Revision: http://reviews.llvm.org/D6279

llvm-svn: 222062

diff --git a/llvm/include/llvm/MC/MCAsmInfo.h b/llvm/include/llvm/MC/MCAsmInfo.h
index 7740fef..4f38aac 100644 (file)
--- a/llvm/include/llvm/MC/MCAsmInfo.h
+++ b/llvm/include/llvm/MC/MCAsmInfo.h
@@ -42,11 +42,11 @@ enum class EncodingType {
 }
 
 enum class ExceptionHandling {
-  None,     /// No exception support
-  DwarfCFI, /// DWARF-like instruction based exceptions
-  SjLj,     /// setjmp/longjmp based exceptions
-  ARM,      /// ARM EHABI
-  WinEH,    /// Windows Exception Handling
+  None,         /// No exception support
+  DwarfCFI,     /// DWARF-like instruction based exceptions
+  SjLj,         /// setjmp/longjmp based exceptions
+  ARM,          /// ARM EHABI
+  ItaniumWinEH, /// Itanium EH built on Windows unwind info (.pdata and .xdata)
 };
 
 namespace LCOMM {
@@ -472,12 +472,16 @@ public:
   }
   ExceptionHandling getExceptionHandlingType() const { return ExceptionsType; }
   WinEH::EncodingType getWinEHEncodingType() const { return WinEHEncodingType; }
-  bool isExceptionHandlingDwarf() const {
+
+  /// Return true if the exception handling type uses the language-specific data
+  /// area (LSDA) format specified by the Itanium C++ ABI.
+  bool usesItaniumLSDAForExceptions() const {
     return (ExceptionsType == ExceptionHandling::DwarfCFI ||
             ExceptionsType == ExceptionHandling::ARM ||
-            // Windows handler data still uses DWARF LSDA encoding.
-            ExceptionsType == ExceptionHandling::WinEH);
+            // This Windows EH type uses the Itanium LSDA encoding.
+            ExceptionsType == ExceptionHandling::ItaniumWinEH);
   }
+
   bool doesDwarfUseRelocationsAcrossSections() const {
     return DwarfUsesRelocationsAcrossSections;
   }

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 32bcd6b..70b6b4d 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -241,7 +241,7 @@ bool AsmPrinter::doInitialization(Module &M) {
   case ExceptionHandling::ARM:
     ES = new ARMException(this);
     break;
-  case ExceptionHandling::WinEH:
+  case ExceptionHandling::ItaniumWinEH:
     switch (MAI->getWinEHEncodingType()) {
     default: llvm_unreachable("unsupported unwinding information encoding");
     case WinEH::EncodingType::Itanium:
@@ -701,8 +701,8 @@ AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
 }
 
 bool AsmPrinter::needsSEHMoves() {
-  return MAI->getExceptionHandlingType() == ExceptionHandling::WinEH &&
-    MF->getFunction()->needsUnwindTableEntry();
+  return MAI->getExceptionHandlingType() == ExceptionHandling::ItaniumWinEH &&
+         MF->getFunction()->needsUnwindTableEntry();
 }
 
 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index 74215aa..0dc52da 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -51,7 +51,7 @@ void DwarfCFIException::endModule() {
   if (moveTypeModule == AsmPrinter::CFI_M_Debug)
     Asm->OutStreamer.EmitCFISections(false, true);
 
-  if (!Asm->MAI->isExceptionHandlingDwarf())
+  if (!Asm->MAI->usesItaniumLSDAForExceptions())
     return;
 
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();

diff --git a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
index 58e524c..2bbffb3 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
@@ -237,7 +237,7 @@ computeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
       // instruction between the previous try-range and this one may throw,
       // create a call-site entry with no landing pad for the region between the
       // try-ranges.
-      if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) {
+      if (SawPotentiallyThrowing && Asm->MAI->usesItaniumLSDAForExceptions()) {
         CallSiteEntry Site = { LastLabel, BeginLabel, nullptr, 0 };
         CallSites.push_back(Site);
         PreviousIsInvoke = false;
@@ -259,7 +259,7 @@ computeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
         };
 
         // Try to merge with the previous call-site. SJLJ doesn't do this
-        if (PreviousIsInvoke && Asm->MAI->isExceptionHandlingDwarf()) {
+        if (PreviousIsInvoke && Asm->MAI->usesItaniumLSDAForExceptions()) {
           CallSiteEntry &Prev = CallSites.back();
           if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
             // Extend the range of the previous entry.
@@ -269,7 +269,7 @@ computeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
         }
 
         // Otherwise, create a new call-site.
-        if (Asm->MAI->isExceptionHandlingDwarf())
+        if (Asm->MAI->usesItaniumLSDAForExceptions())
           CallSites.push_back(Site);
         else {
           // SjLj EH must maintain the call sites in the order assigned
@@ -287,7 +287,7 @@ computeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
   // If some instruction between the previous try-range and the end of the
   // function may throw, create a call-site entry with no landing pad for the
   // region following the try-range.
-  if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) {
+  if (SawPotentiallyThrowing && Asm->MAI->usesItaniumLSDAForExceptions()) {
     CallSiteEntry Site = { LastLabel, nullptr, nullptr, 0 };
     CallSites.push_back(Site);
   }
@@ -520,7 +520,7 @@ void EHStreamer::emitExceptionTable() {
     }
   } else {
     // DWARF Exception handling
-    assert(Asm->MAI->isExceptionHandlingDwarf());
+    assert(Asm->MAI->usesItaniumLSDAForExceptions());
 
     // The call-site table is a list of all call sites that may throw an
     // exception (including C++ 'throw' statements) in the procedure

diff --git a/llvm/lib/CodeGen/Passes.cpp b/llvm/lib/CodeGen/Passes.cpp
index b8b9311..644cc97 100644 (file)
--- a/llvm/lib/CodeGen/Passes.cpp
+++ b/llvm/lib/CodeGen/Passes.cpp
@@ -429,7 +429,7 @@ void TargetPassConfig::addPassesToHandleExceptions() {
     // FALLTHROUGH
   case ExceptionHandling::DwarfCFI:
   case ExceptionHandling::ARM:
-  case ExceptionHandling::WinEH:
+  case ExceptionHandling::ItaniumWinEH:
     addPass(createDwarfEHPass(TM));
     break;
   case ExceptionHandling::None:

diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp
index 3a67f6a..5679d63 100644 (file)
--- a/llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp
@@ -137,7 +137,7 @@ X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
     PrivateGlobalPrefix = ".L";
     PointerSize = 8;
     WinEHEncodingType = WinEH::EncodingType::Itanium;
-    ExceptionsType = ExceptionHandling::WinEH;
+    ExceptionsType = ExceptionHandling::ItaniumWinEH;
   }
 
   AssemblerDialect = AsmWriterFlavor;
@@ -157,7 +157,7 @@ X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
     PrivateGlobalPrefix = ".L";
     PointerSize = 8;
     WinEHEncodingType = WinEH::EncodingType::Itanium;
-    ExceptionsType = ExceptionHandling::WinEH;
+    ExceptionsType = ExceptionHandling::ItaniumWinEH;
   } else {
     ExceptionsType = ExceptionHandling::DwarfCFI;
   }

diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index 6e6bedb..b9920b1 100644 (file)
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -482,9 +482,9 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
   // standard x86_64 and NaCl use 64-bit frame/stack pointers, x32 - 32-bit.
   const bool Uses64BitFramePtr = STI.isTarget64BitLP64() || STI.isTargetNaCl64();
   bool IsWin64 = STI.isTargetWin64();
-  bool IsWinEH =
-      MF.getTarget().getMCAsmInfo()->getExceptionHandlingType() ==
-      ExceptionHandling::WinEH; // Not necessarily synonymous with IsWin64.
+  // Not necessarily synonymous with IsWin64.
+  bool IsWinEH = MF.getTarget().getMCAsmInfo()->getExceptionHandlingType() ==
+                 ExceptionHandling::ItaniumWinEH;
   bool NeedsWinEH = IsWinEH && Fn->needsUnwindTableEntry();
   bool NeedsDwarfCFI =
       !IsWinEH && (MMI.hasDebugInfo() || Fn->needsUnwindTableEntry());
@@ -883,9 +883,8 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
              getX86SubSuperRegister(FramePtr, MVT::i64, false) : FramePtr;
   unsigned StackPtr = RegInfo->getStackRegister();
 
-  bool IsWinEH =
-      MF.getTarget().getMCAsmInfo()->getExceptionHandlingType() ==
-      ExceptionHandling::WinEH;
+  bool IsWinEH = MF.getTarget().getMCAsmInfo()->getExceptionHandlingType() ==
+                 ExceptionHandling::ItaniumWinEH;
   bool NeedsWinEH = IsWinEH && MF.getFunction()->needsUnwindTableEntry();
 
   switch (RetOpcode) {