[llvm] r179220 - Track the compact unwind encoding for when we are unable to generate compact unwind information.

[Bill Wendling]

Author: void
Date: Wed Apr 10 16:42:06 2013
New Revision: 179220

URL: http://llvm.org/viewvc/llvm-project?rev=179220&view=rev
Log:
Track the compact unwind encoding for when we are unable to generate compact unwind information.

Compact unwind has an encoding for when we're not able to generate compact
unwind and must generate an EH frame instead. Track that, but still emit that CU
encoding.

Modified:
    llvm/trunk/include/llvm/MC/MCObjectFileInfo.h
    llvm/trunk/lib/MC/MCDwarf.cpp
    llvm/trunk/lib/MC/MCObjectFileInfo.cpp

Modified: llvm/trunk/include/llvm/MC/MCObjectFileInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCObjectFileInfo.h?rev=179220&r1=179219&r2=179220&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCObjectFileInfo.h (original)
+++ llvm/trunk/include/llvm/MC/MCObjectFileInfo.h Wed Apr 10 16:42:06 2013
@@ -46,10 +46,15 @@ protected:
   unsigned FDEEncoding;
   unsigned FDECFIEncoding;
   unsigned TTypeEncoding;
-  // Section flags for eh_frame
+
+  /// Section flags for eh_frame
   unsigned EHSectionType;
   unsigned EHSectionFlags;
 
+  /// CompactUnwindDwarfEHFrameOnly - Compact unwind encoding indicating that we
+  /// should emit only an EH frame.
+  unsigned CompactUnwindDwarfEHFrameOnly;
+
   /// TextSection - Section directive for standard text.
   ///
   const MCSection *TextSection;
@@ -201,6 +206,10 @@ public:
   }
   unsigned getTTypeEncoding() const { return TTypeEncoding; }
 
+  unsigned getCompactUnwindDwarfEHFrameOnly() const {
+    return CompactUnwindDwarfEHFrameOnly;
+  }
+
   const MCSection *getTextSection() const { return TextSection; }
   const MCSection *getDataSection() const { return DataSection; }
   const MCSection *getBSSSection() const { return BSSSection; }

Modified: llvm/trunk/lib/MC/MCDwarf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCDwarf.cpp?rev=179220&r1=179219&r2=179220&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCDwarf.cpp (original)
+++ llvm/trunk/lib/MC/MCDwarf.cpp Wed Apr 10 16:42:06 2013
@@ -1168,10 +1168,10 @@ bool FrameEmitterImpl::EmitCompactUnwind
   //   .quad except_tab1
 
   uint32_t Encoding = Frame.CompactUnwindEncoding;
-  if (!Encoding) return false;
+  bool DwarfEHFrameOnly = (Encoding == MOFI->getCompactUnwindDwarfEHFrameOnly());
 
   // The encoding needs to know we have an LSDA.
-  if (Frame.Lsda)
+  if (!DwarfEHFrameOnly && Frame.Lsda)
     Encoding |= 0x40000000;
 
   Streamer.SwitchSection(MOFI->getCompactUnwindSection());
@@ -1194,11 +1194,10 @@ bool FrameEmitterImpl::EmitCompactUnwind
                                       Twine::utohexstr(Encoding));
   Streamer.EmitIntValue(Encoding, Size);
 
-
   // Personality Function
   Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
   if (VerboseAsm) Streamer.AddComment("Personality Function");
-  if (Frame.Personality)
+  if (!DwarfEHFrameOnly && Frame.Personality)
     Streamer.EmitSymbolValue(Frame.Personality, Size);
   else
     Streamer.EmitIntValue(0, Size); // No personality fn
@@ -1206,7 +1205,7 @@ bool FrameEmitterImpl::EmitCompactUnwind
   // LSDA
   Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
   if (VerboseAsm) Streamer.AddComment("LSDA");
-  if (Frame.Lsda)
+  if (!DwarfEHFrameOnly && Frame.Lsda)
     Streamer.EmitSymbolValue(Frame.Lsda, Size);
   else
     Streamer.EmitIntValue(0, Size); // No LSDA

Modified: llvm/trunk/lib/MC/MCObjectFileInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectFileInfo.cpp?rev=179220&r1=179219&r2=179220&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectFileInfo.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectFileInfo.cpp Wed Apr 10 16:42:06 2013
@@ -145,12 +145,16 @@ void MCObjectFileInfo::InitMachOMCObject
   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
                                      SectionKind::getReadOnlyWithRel());
 
-  if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
+  if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6)) {
     CompactUnwindSection =
       Ctx->getMachOSection("__LD", "__compact_unwind",
                            MCSectionMachO::S_ATTR_DEBUG,
                            SectionKind::getReadOnly());
 
+    if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
+      CompactUnwindDwarfEHFrameOnly = 0x04000000;
+  }
+
   // Debug Information.
   DwarfAccelNamesSection =
     Ctx->getMachOSection("__DWARF", "__apple_names",
@@ -629,6 +633,8 @@ void MCObjectFileInfo::InitMCObjectFileI
   PersonalityEncoding = LSDAEncoding = FDEEncoding = FDECFIEncoding =
     TTypeEncoding = dwarf::DW_EH_PE_absptr;
 
+  CompactUnwindDwarfEHFrameOnly = 0;
+
   EHFrameSection = 0;             // Created on demand.
   CompactUnwindSection = 0;       // Used only by selected targets.
   DwarfAccelNamesSection = 0;     // Used only by selected targets.