Add a possibility to switch between CFI directives- and table-based frame description emission. Currently all the backends use table-based stuff.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123476 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCAsmInfo.h

@@ -25,7 +25,9 @@ namespace llvm {
 
   /// MCAsmInfo - This class is intended to be used as a base class for asm
   /// properties and features specific to the target.
-  namespace ExceptionHandling { enum ExceptionsType { None, Dwarf, SjLj }; }
+  namespace ExceptionHandling {
+    enum ExceptionsType { None, DwarfTable, DwarfCFI, SjLj };
+  }
 
   class MCAsmInfo {
   protected:
@@ -438,6 +440,12 @@ namespace llvm {
     ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
       return ExceptionsType;
     }
+    bool isExceptionHandlingDwarf() const {
+      return
+        (ExceptionsType == ExceptionHandling::DwarfTable ||
+         ExceptionsType == ExceptionHandling::DwarfCFI);
+    }
+
     bool doesDwarfRequireFrameSection() const {
       return DwarfRequiresFrameSection;
     }

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -188,7 +188,15 @@ bool AsmPrinter::doInitialization(Module &M) {
     DD = new DwarfDebug(this, &M);
 
   if (MAI->doesSupportExceptionHandling())
-    DE = new DwarfTableException(this);
+    switch (MAI->getExceptionHandlingType()) {
+    default:
+    case ExceptionHandling::DwarfTable:
+      DE = new DwarfTableException(this);
+      break;
+    case ExceptionHandling::DwarfCFI:
+      DE = new DwarfCFIException(this);
+      break;
+    }
 
   return false;
 }

lib/CodeGen/AsmPrinter/DwarfCFIException.cpp

@@ -48,7 +48,7 @@ DwarfCFIException::~DwarfCFIException() {}
 /// EndModule - Emit all exception information that should come after the
 /// content.
 void DwarfCFIException::EndModule() {
-  if (Asm->MAI->getExceptionHandlingType() != ExceptionHandling::Dwarf)
+  if (!Asm->MAI->isExceptionHandlingDwarf())
     return;
 
   if (!shouldEmitTableModule)

lib/CodeGen/AsmPrinter/DwarfException.cpp

@@ -269,8 +269,7 @@ 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 &&
+      if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) {
-          Asm->MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf) {
         CallSiteEntry Site = { LastLabel, BeginLabel, 0, 0 };
         CallSites.push_back(Site);
         PreviousIsInvoke = false;
@@ -292,8 +291,7 @@ ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
         };
 
         // Try to merge with the previous call-site. SJLJ doesn't do this
-        if (PreviousIsInvoke &&
+        if (PreviousIsInvoke && Asm->MAI->isExceptionHandlingDwarf()) {
-          Asm->MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf) {
           CallSiteEntry &Prev = CallSites.back();
           if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
             // Extend the range of the previous entry.
@@ -303,7 +301,7 @@ ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
         }
 
         // Otherwise, create a new call-site.
-        if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf)
+        if (Asm->MAI->isExceptionHandlingDwarf())
           CallSites.push_back(Site);
         else {
           // SjLj EH must maintain the call sites in the order assigned
@@ -321,8 +319,7 @@ 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 &&
+  if (SawPotentiallyThrowing && Asm->MAI->isExceptionHandlingDwarf()) {
-      Asm->MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf) {
     CallSiteEntry Site = { LastLabel, 0, 0, 0 };
     CallSites.push_back(Site);
   }
@@ -536,7 +533,7 @@ void DwarfException::EmitExceptionTable() {
     }
   } else {
     // DWARF Exception handling
-    assert(Asm->MAI->getExceptionHandlingType() == ExceptionHandling::Dwarf);
+    assert(Asm->MAI->isExceptionHandlingDwarf());
 
     // The call-site table is a list of all call sites that may throw an
     // exception (including C++ 'throw' statements) in the procedure

lib/CodeGen/AsmPrinter/DwarfTableException.cpp

@@ -277,7 +277,7 @@ void DwarfTableException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
 /// EndModule - Emit all exception information that should come after the
 /// content.
 void DwarfTableException::EndModule() {
-  if (Asm->MAI->getExceptionHandlingType() != ExceptionHandling::Dwarf)
+  if (!Asm->MAI->isExceptionHandlingDwarf())
     return;
 
   if (!shouldEmitMovesModule && !shouldEmitTableModule)

lib/CodeGen/LLVMTargetMachine.cpp

@@ -301,7 +301,8 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
     // edge from elsewhere.
     PM.add(createSjLjEHPass(getTargetLowering()));
     // FALLTHROUGH
-  case ExceptionHandling::Dwarf:
+  case ExceptionHandling::DwarfCFI:
+  case ExceptionHandling::DwarfTable:
     PM.add(createDwarfEHPass(this));
     break;
   case ExceptionHandling::None:

lib/Target/PowerPC/PPCMCAsmInfo.cpp

@@ -17,7 +17,7 @@ using namespace llvm;
 PPCMCAsmInfoDarwin::PPCMCAsmInfoDarwin(bool is64Bit) {
   PCSymbol = ".";
   CommentString = ";";
-  ExceptionsType = ExceptionHandling::Dwarf;
+  ExceptionsType = ExceptionHandling::DwarfTable;
 
   if (!is64Bit)
     Data64bitsDirective = 0;      // We can't emit a 64-bit unit in PPC32 mode.
@@ -48,7 +48,7 @@ PPCLinuxMCAsmInfo::PPCLinuxMCAsmInfo(bool is64Bit) {
 
   // Exceptions handling
   if (!is64Bit)
-    ExceptionsType = ExceptionHandling::Dwarf;
+    ExceptionsType = ExceptionHandling::DwarfTable;
     
   ZeroDirective = "\t.space\t";
   Data64bitsDirective = is64Bit ? "\t.quad\t" : 0;

lib/Target/X86/X86MCAsmInfo.cpp

@@ -68,7 +68,7 @@ X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &Triple) {
   DwarfUsesInlineInfoSection = true;
 
   // Exceptions handling
-  ExceptionsType = ExceptionHandling::Dwarf;
+  ExceptionsType = ExceptionHandling::DwarfTable;
 }
 
 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
@@ -88,8 +88,8 @@ X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
   SupportsDebugInformation = true;
 
   // Exceptions handling
-  ExceptionsType = ExceptionHandling::Dwarf;
+  ExceptionsType = ExceptionHandling::DwarfTable;
-  
+
   // OpenBSD has buggy support for .quad in 32-bit mode, just split into two
   // .words.
   if (T.getOS() == Triple::OpenBSD && T.getArch() == Triple::x86)