Big change #1 for personality function references:

Eliminate the PersonalityPrefix/Suffix & NeedsIndirectEncoding
fields from MAI: they aren't part of the asm syntax, they are
related to the structure of the object file.

To replace their functionality, add a new 
TLOF::getSymbolForDwarfGlobalReference method which asks targets
to decide how to reference a global from EH in a pc-relative way.

The default implementation just returns the symbol.  The default
darwin implementation references the symbol through an indirect
$non_lazy_ptr stub.  The bizarro x86-64 darwin specialization
handles the weird "foo@GOTPCREL+4" hack.

DwarfException.cpp now uses this to emit the reference to the
symbol in the right way, and this also eliminates another 
horrible hack from DwarfException.cpp:

-    if (strcmp(MAI->getPersonalitySuffix(), "+4@GOTPCREL"))
-      O << "-" << MAI->getPCSymbol();



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81991 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCAsmInfo.h

@@ -84,17 +84,6 @@ namespace llvm {
     /// is "l" on Darwin, currently used for some ObjC metadata.
     const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
     
-    /// PersonalityPrefix/Suffix - If these are nonempty, these strings will
-    /// enclose any personality function in the common frame section.
-    /// 
-    const char *PersonalityPrefix;           // Defaults to ""
-    const char *PersonalitySuffix;           // Defaults to ""
-
-    /// NeedsIndirectEncoding - If set, we need to set the indirect encoding bit
-    /// for EH in Dwarf.
-    /// 
-    bool NeedsIndirectEncoding;              // Defaults to false
-
     /// InlineAsmStart/End - If these are nonempty, they contain a directive to
     /// emit before and after an inline assembly statement.
     const char *InlineAsmStart;              // Defaults to "#APP\n"
@@ -353,15 +342,6 @@ namespace llvm {
     const char *getLinkerPrivateGlobalPrefix() const {
       return LinkerPrivateGlobalPrefix;
     }
-    const char *getPersonalityPrefix() const {
-      return PersonalityPrefix;
-    }
-    const char *getPersonalitySuffix() const {
-      return PersonalitySuffix;
-    }
-    bool getNeedsIndirectEncoding() const {
-      return NeedsIndirectEncoding;
-    }
     const char *getInlineAsmStart() const {
       return InlineAsmStart;
     }

include/llvm/Target/TargetLoweringObjectFile.h

@@ -26,6 +26,7 @@ namespace llvm {
   class StringRef;
   class TargetMachine;
   class MCAsmInfo;
+  class MCExpr;
   
 class TargetLoweringObjectFile {
   MCContext *Ctx;
@@ -173,6 +174,22 @@ public:
     return 0;
   }
   
+  /// getSymbolForDwarfGlobalReference - Return an MCExpr to use for a
+  /// pc-relative reference to the specified global variable from exception
+  /// handling information.  In addition to the symbol, this returns
+  /// by-reference:
+  ///
+  /// IsIndirect - True if the returned symbol is actually a stub that contains
+  ///    the address of the symbol, false if the symbol is the global itself.
+  ///
+  /// IsPCRel - True if the symbol reference is already pc-relative, false if
+  ///    the caller needs to subtract off the address of the reference from the
+  ///    symbol.
+  ///
+  virtual const MCExpr *
+  getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                                   bool &IsIndirect, bool &IsPCRel) const;
+  
 protected:
   virtual const MCSection *
   SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
@@ -298,6 +315,12 @@ public:
   const MCSection *getNonLazySymbolPointerSection() const {
     return NonLazySymbolPointerSection;
   }
+  
+  /// getSymbolForDwarfGlobalReference - The mach-o version of this method
+  /// defaults to returning a stub reference.
+  virtual const MCExpr *
+  getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                                   bool &IsIndirect, bool &IsPCRel) const;
 };
 
 

lib/CodeGen/AsmPrinter/DwarfException.cpp

@@ -17,9 +17,11 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineLocation.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCStreamer.h"
-#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetFrameInfo.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
@@ -75,20 +77,22 @@ unsigned DwarfException::SizeOfEncodedValue(unsigned Encoding) {
 /// EmitCIE - Emit a Common Information Entry (CIE). This holds information that
 /// is shared among many Frame Description Entries.  There is at least one CIE
 /// in every non-empty .debug_frame section.
-void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
+void DwarfException::EmitCIE(const Function *PersonalityFn, unsigned Index) {
   // Size and sign of stack growth.
   int stackGrowth =
     Asm->TM.getFrameInfo()->getStackGrowthDirection() ==
     TargetFrameInfo::StackGrowsUp ?
     TD->getPointerSize() : -TD->getPointerSize();
 
+  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+  
   // Begin eh frame section.
-  Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering().getEHFrameSection());
+  Asm->OutStreamer.SwitchSection(TLOF.getEHFrameSection());
 
   if (MAI->is_EHSymbolPrivate())
     O << MAI->getPrivateGlobalPrefix();
-
   O << "EH_frame" << Index << ":\n";
+  
   EmitLabel("section_eh_frame", Index);
 
   // Define base labels.
@@ -107,11 +111,22 @@ void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
   Asm->EOL("CIE Version");
 
   // The personality presence indicates that language specific information will
-  // show up in the eh frame.
-
-  // FIXME: Don't hardcode these encodings.
+  // show up in the eh frame.  Find out how we are supposed to lower the
+  // personality function reference:
+  const MCExpr *PersonalityRef = 0;
+  bool IsPersonalityIndirect = false, IsPersonalityPCRel = false;
+  if (PersonalityFn) {
+    // FIXME: HANDLE STATIC CODEGEN MODEL HERE.
+    
+    // In non-static mode, ask the object file how to represent this reference.
+    PersonalityRef =
+      TLOF.getSymbolForDwarfGlobalReference(PersonalityFn, Asm->Mang,
+                                            IsPersonalityIndirect,
+                                            IsPersonalityPCRel);
+  }
+  
   unsigned PerEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
-  if (Personality && MAI->getNeedsIndirectEncoding())
+  if (IsPersonalityIndirect)
     PerEncoding |= dwarf::DW_EH_PE_indirect;
   unsigned LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
   unsigned FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
@@ -120,7 +135,7 @@ void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
   unsigned AugmentationSize = 0;
   char *APtr = Augmentation + 1;
 
-  if (Personality) {
+  if (PersonalityRef) {
     // There is a personality function.
     *APtr++ = 'P';
     AugmentationSize += 1 + SizeOfEncodedValue(PerEncoding);
@@ -159,15 +174,27 @@ void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
   Asm->EOL("Personality", PerEncoding);
 
   // If there is a personality, we need to indicate the function's location.
-  if (Personality) {
+  if (PersonalityRef) {
+    // If the reference to the personality function symbol is not already
+    // pc-relative, then we need to subtract our current address from it.  Do
+    // this by emitting a label and subtracting it from the expression we
+    // already have.  This is equivalent to emitting "foo - .", but we have to
+    // emit the label for "." directly.
+    if (!IsPersonalityPCRel) {
+      SmallString<64> Name;
+      raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix()
+         << "personalityref_addr" << Asm->getFunctionNumber() << "_" << Index;
+      MCSymbol *DotSym = Asm->OutContext.GetOrCreateSymbol(Name.str());
+      Asm->OutStreamer.EmitLabel(DotSym);
+      
+      PersonalityRef =  
+        MCBinaryExpr::CreateSub(PersonalityRef,
+                                MCSymbolRefExpr::Create(DotSym,Asm->OutContext),
+                                Asm->OutContext);
+    }
+    
     O << MAI->getData32bitsDirective();
-    
-    O << MAI->getPersonalityPrefix();
-    O << Asm->Mang->getMangledName(Personality);
-    O << MAI->getPersonalitySuffix();
-    
-    if (strcmp(MAI->getPersonalitySuffix(), "+4@GOTPCREL"))
-      O << "-" << MAI->getPCSymbol();
+    PersonalityRef->print(O, MAI);
     Asm->EOL("Personality");
 
     Asm->EmitInt8(LSDAEncoding);
@@ -185,8 +212,7 @@ void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
   // On Darwin the linker honors the alignment of eh_frame, which means it must
   // be 8-byte on 64-bit targets to match what gcc does.  Otherwise you get
   // holes which confuse readers of eh_frame.
-  Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
-                     0, 0, false);
+  Asm->EmitAlignment(TD->getPointerSize() == 4 ? 2 : 3, 0, 0, false);
   EmitLabel("eh_frame_common_end", Index);
 
   Asm->EOL();

lib/MC/MCAsmInfo.cpp

@@ -30,9 +30,6 @@ MCAsmInfo::MCAsmInfo() {
   GlobalPrefix = "";
   PrivateGlobalPrefix = ".";
   LinkerPrivateGlobalPrefix = "";
-  PersonalityPrefix = "";
-  PersonalitySuffix = "";
-  NeedsIndirectEncoding = false;
   InlineAsmStart = "APP";
   InlineAsmEnd = "NO_APP";
   AssemblerDialect = 0;

lib/MC/MCAsmInfoDarwin.cpp

@@ -20,9 +20,8 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
   // Syntax:
   GlobalPrefix = "_";
   PrivateGlobalPrefix = "L";
-  LinkerPrivateGlobalPrefix = "l";  // Marker for some ObjC metadata
+  LinkerPrivateGlobalPrefix = "l";
   NeedsSet = true;
-  NeedsIndirectEncoding = true;
   AllowQuotesInName = true;
   HasSingleParameterDotFile = false;
 

lib/Target/PowerPC/PPCMCAsmInfo.cpp

@@ -22,9 +22,6 @@ PPCMCAsmInfoDarwin::PPCMCAsmInfoDarwin(bool is64Bit) {
   if (!is64Bit)
     Data64bitsDirective = 0;      // We can't emit a 64-bit unit in PPC32 mode.
   AssemblerDialect = 1;           // New-Style mnemonics.
-  
-  PersonalityPrefix = "L";
-  PersonalitySuffix = "$non_lazy_ptr";
 }
 
 PPCLinuxMCAsmInfo::PPCLinuxMCAsmInfo(bool is64Bit) {

lib/Target/TargetLoweringObjectFile.cpp

@@ -18,6 +18,7 @@
 #include "llvm/Function.h"
 #include "llvm/GlobalVariable.h"
 #include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCSectionMachO.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/Target/TargetData.h"
@@ -275,6 +276,30 @@ TargetLoweringObjectFile::getSectionForConstant(SectionKind Kind) const {
   return DataSection;
 }
 
+/// getSymbolForDwarfGlobalReference - Return an MCExpr to use for a
+/// pc-relative reference to the specified global variable from exception
+/// handling information.  In addition to the symbol, this returns
+/// by-reference:
+///
+/// IsIndirect - True if the returned symbol is actually a stub that contains
+///    the address of the symbol, false if the symbol is the global itself.
+///
+/// IsPCRel - True if the symbol reference is already pc-relative, false if
+///    the caller needs to subtract off the address of the reference from the
+///    symbol.
+///
+const MCExpr *TargetLoweringObjectFile::
+getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                                 bool &IsIndirect, bool &IsPCRel) const {
+  // The generic implementation of this just returns a direct reference to the
+  // symbol.
+  IsIndirect = false;
+  IsPCRel    = false;
+  
+  SmallString<128> Name;
+  Mang->getNameWithPrefix(Name, GV, false);
+  return MCSymbolRefExpr::Create(Name.str(), getContext());
+}
 
 
 //===----------------------------------------------------------------------===//
@@ -929,6 +954,19 @@ shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
   return true;
 }
 
+const MCExpr *TargetLoweringObjectFileMachO::
+getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                                 bool &IsIndirect, bool &IsPCRel) const {
+  // The mach-o version of this method defaults to returning a stub reference.
+  IsIndirect = true;
+  IsPCRel    = false;
+  
+  SmallString<128> Name;
+  Mang->getNameWithPrefix(Name, GV, true);
+  Name += "$non_lazy_ptr";
+  return MCSymbolRefExpr::Create(Name.str(), getContext());
+}
+
 
 //===----------------------------------------------------------------------===//
 //                                  COFF
@@ -1046,3 +1084,4 @@ SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 
   return getDataSection();
 }
+

lib/Target/X86/X86ISelLowering.cpp

@@ -16,6 +16,7 @@
 #include "X86InstrBuilder.h"
 #include "X86ISelLowering.h"
 #include "X86TargetMachine.h"
+#include "X86TargetObjectFile.h"
 #include "llvm/CallingConv.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
@@ -36,7 +37,6 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
-#include "llvm/Target/TargetLoweringObjectFile.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringExtras.h"
@@ -63,6 +63,8 @@ static TargetLoweringObjectFile *createTLOF(X86TargetMachine &TM) {
   switch (TM.getSubtarget<X86Subtarget>().TargetType) {
   default: llvm_unreachable("unknown subtarget type");
   case X86Subtarget::isDarwin:
+    if (TM.getSubtarget<X86Subtarget>().is64Bit())
+      return new X8664_MachoTargetObjectFile();
     return new TargetLoweringObjectFileMachO();
   case X86Subtarget::isELF:
     return new TargetLoweringObjectFileELF();

lib/Target/X86/X86MCAsmInfo.cpp

@@ -57,14 +57,6 @@ X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &Triple) {
   // Leopard and above support aligned common symbols.
   COMMDirectiveTakesAlignment = Triple.getDarwinMajorNumber() >= 9;
 
-  if (is64Bit) {
-    PersonalityPrefix = "";
-    PersonalitySuffix = "+4@GOTPCREL";
-  } else {
-    PersonalityPrefix = "L";
-    PersonalitySuffix = "$non_lazy_ptr";
-  }
-
   CommentString = "##";
   PCSymbol = ".";
 

lib/Target/X86/X86TargetObjectFile.cpp

@@ -0,0 +1,33 @@
+//===-- llvm/Target/X86/X86TargetObjectFile.cpp - X86 Object Info ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "X86TargetObjectFile.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/Mangler.h"
+#include "llvm/MC/MCExpr.h"
+using namespace llvm;
+
+const MCExpr *X8664_MachoTargetObjectFile::
+getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                                 bool &IsIndirect, bool &IsPCRel) const {
+  
+  // On Darwin/X86-64, we can reference dwarf symbols with foo@GOTPCREL+4, which
+  // is an indirect pc-relative reference.
+  IsIndirect = true;
+  IsPCRel    = true;
+  
+  SmallString<128> Name;
+  Mang->getNameWithPrefix(Name, GV, false);
+  Name += "@GOTPCREL";
+  const MCExpr *Res =
+    MCSymbolRefExpr::Create(Name.str(), getContext());
+  const MCExpr *Four = MCConstantExpr::Create(4, getContext());
+  return MCBinaryExpr::CreateAdd(Res, Four, getContext());
+}
+

lib/Target/X86/X86TargetObjectFile.h

@@ -0,0 +1,28 @@
+//===-- llvm/Target/X86/X86TargetObjectFile.h - X86 Object Info -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TARGET_X86_TARGETOBJECTFILE_H
+#define LLVM_TARGET_X86_TARGETOBJECTFILE_H
+
+#include "llvm/Target/TargetLoweringObjectFile.h"
+
+namespace llvm {
+  
+  /// X8664_MachoTargetObjectFile - This TLOF implementation is used for
+  /// Darwin/x86-64.
+  class X8664_MachoTargetObjectFile : public TargetLoweringObjectFileMachO {
+  public:
+
+    virtual const MCExpr *
+    getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                                     bool &IsIndirect, bool &IsPCRel) const;
+  };
+} // end namespace llvm
+
+#endif