- Add target lowering methods to get the preferred format for the FDE and LSDA

encodings.
- Make some of the values emitted by the FDEs dependent upon the pointer
  size. This is in line with how GCC does things. And it has the benefit of
  working for Darwin in 64-bit mode now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80428 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetLowering.h

@@ -32,6 +32,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/DebugLoc.h"
+#include "llvm/Support/Dwarf.h"
 #include "llvm/Target/TargetMachine.h"
 #include <climits>
 #include <map>
@@ -750,7 +751,7 @@ public:
   /// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
   /// jumptable.
   virtual SDValue getPICJumpTableRelocBase(SDValue Table,
-                                             SelectionDAG &DAG) const;
+                                           SelectionDAG &DAG) const;
 
   /// isOffsetFoldingLegal - Return true if folding a constant offset
   /// with the given GlobalAddress is legal.  It is frequently not legal in
@@ -760,6 +761,18 @@ public:
   /// getFunctionAlignment - Return the Log2 alignment of this function.
   virtual unsigned getFunctionAlignment(const Function *) const = 0;
 
+  /// getPreferredLSDADataFormat - Return the preferred exception handling data
+  /// format for the LSDA.
+  virtual unsigned getPreferredLSDADataFormat() const {
+    return dwarf::DW_EH_PE_absptr;
+  }
+
+  /// getPreferredFDEDataFormat - Return the preferred exception handling data
+  /// format for the FDE.
+  virtual unsigned getPreferredFDEDataFormat() const {
+    return dwarf::DW_EH_PE_absptr;
+  }
+
   //===--------------------------------------------------------------------===//
   // TargetLowering Optimization Methods
   //

lib/CodeGen/AsmPrinter/DwarfException.cpp

@@ -22,6 +22,7 @@
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetFrameInfo.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Support/Dwarf.h"
@@ -80,6 +81,7 @@ void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
   EmitLabel("eh_frame_common_begin", Index);
   Asm->EmitInt32((int)0);
   Asm->EOL("CIE Identifier Tag");
+
   Asm->EmitInt8(dwarf::DW_CIE_VERSION);
   Asm->EOL("CIE Version");
 
@@ -91,23 +93,29 @@ void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
   // Round out reader.
   Asm->EmitULEB128Bytes(1);
   Asm->EOL("CIE Code Alignment Factor");
+
   Asm->EmitSLEB128Bytes(stackGrowth);
   Asm->EOL("CIE Data Alignment Factor");
+
   Asm->EmitInt8(RI->getDwarfRegNum(RI->getRARegister(), true));
   Asm->EOL("CIE Return Address Column");
 
+  unsigned Encoding = 0;
+
   // If there is a personality, we need to indicate the function's location.
   if (Personality) {
     Asm->EmitULEB128Bytes(7);
     Asm->EOL("Augmentation Size");
 
     if (MAI->getNeedsIndirectEncoding()) {
-      Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
-                    dwarf::DW_EH_PE_indirect);
-      Asm->EOL("Personality (pcrel sdata4 indirect)");
+      Encoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
+        dwarf::DW_EH_PE_indirect;
+      Asm->EmitInt8(Encoding);
+      Asm->EOL("Personality", Encoding);
     } else {
-      Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
-      Asm->EOL("Personality (pcrel sdata4)");
+      Encoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+      Asm->EmitInt8(Encoding);
+      Asm->EOL("Personality", Encoding);
     }
 
     PrintRelDirective(true);
@@ -118,17 +126,20 @@ void DwarfException::EmitCIE(const Function *Personality, unsigned Index) {
       O << "-" << MAI->getPCSymbol();
     Asm->EOL("Personality");
 
-    Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
-    Asm->EOL("LSDA Encoding (pcrel sdata4)");
+    Encoding = Asm->TM.getTargetLowering()->getPreferredLSDADataFormat();
+    Asm->EmitInt8(Encoding);
+    Asm->EOL("LSDA Encoding", Encoding);
 
-    Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
-    Asm->EOL("FDE Encoding (pcrel sdata4)");
+    Encoding = Asm->TM.getTargetLowering()->getPreferredFDEDataFormat();
+    Asm->EmitInt8(Encoding);
+    Asm->EOL("FDE Encoding", Encoding);
   } else {
     Asm->EmitULEB128Bytes(1);
     Asm->EOL("Augmentation Size");
 
-    Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
-    Asm->EOL("FDE Encoding (pcrel sdata4)");
+    Encoding = Asm->TM.getTargetLowering()->getPreferredFDEDataFormat();
+    Asm->EmitInt8(Encoding);
+    Asm->EOL("FDE Encoding", Encoding);
   }
 
   // Indicate locations of general callee saved registers in frame.
@@ -152,6 +163,7 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
          "Should not emit 'available externally' functions at all");
 
   const Function *TheFunc = EHFrameInfo.function;
+  bool is4Byte = TD->getPointerSize() == sizeof(int32_t);
 
   Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering().getEHFrameSection());
 
@@ -195,23 +207,22 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
 
     Asm->EOL("FDE CIE offset");
 
-    EmitReference("eh_func_begin", EHFrameInfo.Number, true, true);
+    EmitReference("eh_func_begin", EHFrameInfo.Number, true, is4Byte);
     Asm->EOL("FDE initial location");
+
     EmitDifference("eh_func_end", EHFrameInfo.Number,
-                   "eh_func_begin", EHFrameInfo.Number, true);
+                   "eh_func_begin", EHFrameInfo.Number, is4Byte);
     Asm->EOL("FDE address range");
 
     // If there is a personality and landing pads then point to the language
     // specific data area in the exception table.
     if (MMI->getPersonalities()[0] != NULL) {
-      bool is4Byte = TD->getPointerSize() == sizeof(int32_t);
-
       Asm->EmitULEB128Bytes(is4Byte ? 4 : 8);
       Asm->EOL("Augmentation size");
 
-      if (EHFrameInfo.hasLandingPads)
+      if (EHFrameInfo.hasLandingPads) {
         EmitReference("exception", EHFrameInfo.Number, true, false);
-      else {
+      } else {
 	if (is4Byte)
 	  Asm->EmitInt32((int)0);
 	else
@@ -918,6 +929,8 @@ void DwarfException::EndFunction() {
                             MF->getFunction()));
   }
 
+  MF = 0;
+
   if (TimePassesIsEnabled)
     ExceptionTimer->stopTimer();
 }

lib/Target/PowerPC/PPCISelLowering.cpp

@@ -464,6 +464,40 @@ unsigned PPCTargetLowering::getFunctionAlignment(const Function *F) const {
     return 2;
 }
 
+/// getPreferredLSDADataFormat - Return the preferred exception handling data
+/// format for the LSDA.
+unsigned PPCTargetLowering::getPreferredLSDADataFormat() const {
+  if (getTargetMachine().getSubtarget<PPCSubtarget>().isDarwin())
+    return dwarf::DW_EH_PE_pcrel;
+
+  if (PPCSubTarget.isPPC64() ||
+      getTargetMachine().getRelocationModel() == Reloc::PIC_) {
+    unsigned DataTy =
+      (PPCSubTarget.isPPC64() ?
+       dwarf::DW_EH_PE_udata8 : dwarf::DW_EH_PE_udata4);
+    return dwarf::DW_EH_PE_pcrel | DataTy;
+  }
+
+  return dwarf::DW_EH_PE_absptr;
+}
+
+/// getPreferredFDEDataFormat - Return the preferred exception handling data
+/// format for the FDE.
+unsigned PPCTargetLowering::getPreferredFDEDataFormat() const {
+  if (getTargetMachine().getSubtarget<PPCSubtarget>().isDarwin())
+    return dwarf::DW_EH_PE_pcrel;
+
+  if (PPCSubTarget.isPPC64() ||
+      getTargetMachine().getRelocationModel() == Reloc::PIC_) {
+    unsigned DataTy =
+      (PPCSubTarget.isPPC64() ?
+       dwarf::DW_EH_PE_udata8 : dwarf::DW_EH_PE_udata4);
+    return dwarf::DW_EH_PE_pcrel | DataTy;
+  }
+
+  return dwarf::DW_EH_PE_absptr;
+}
+
 //===----------------------------------------------------------------------===//
 // Node matching predicates, for use by the tblgen matching code.
 //===----------------------------------------------------------------------===//

lib/Target/PowerPC/PPCISelLowering.h

@@ -346,6 +346,14 @@ namespace llvm {
     /// getFunctionAlignment - Return the Log2 alignment of this function.
     virtual unsigned getFunctionAlignment(const Function *F) const;
 
+    /// getPreferredLSDADataFormat - Return the preferred exception handling data
+    /// format for the LSDA.
+    virtual unsigned getPreferredLSDADataFormat() const;
+
+    /// getPreferredFDEDataFormat - Return the preferred exception handling data
+    /// format for the FDE.
+    virtual unsigned getPreferredFDEDataFormat() const;
+
   private:
     SDValue getFramePointerFrameIndex(SelectionDAG & DAG) const;
     SDValue getReturnAddrFrameIndex(SelectionDAG & DAG) const;

lib/Target/X86/X86ISelLowering.cpp

@@ -1055,6 +1055,49 @@ unsigned X86TargetLowering::getFunctionAlignment(const Function *F) const {
   return F->hasFnAttr(Attribute::OptimizeForSize) ? 0 : 4;
 }
 
+/// getPreferredLSDADataFormat - Return the preferred exception handling data
+/// format for the LSDA.
+unsigned X86TargetLowering::getPreferredLSDADataFormat() const {
+  if (Subtarget->isTargetDarwin())
+    return dwarf::DW_EH_PE_pcrel;
+
+  CodeModel::Model M = getTargetMachine().getCodeModel();
+
+  if (getTargetMachine().getRelocationModel() == Reloc::PIC_) {
+    if (!Subtarget->is64Bit() || M == CodeModel::Small)
+      return dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+
+    return dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
+  }
+
+  if (M == CodeModel::Small)
+    return dwarf::DW_EH_PE_sdata4;
+
+  return dwarf::DW_EH_PE_absptr;
+}
+
+/// getPreferredFDEDataFormat - Return the preferred exception handling data
+/// format for the FDE.
+unsigned X86TargetLowering::getPreferredFDEDataFormat() const {
+  if (Subtarget->isTargetDarwin())
+    return dwarf::DW_EH_PE_pcrel;
+
+  CodeModel::Model M = getTargetMachine().getCodeModel();
+
+  if (getTargetMachine().getRelocationModel() == Reloc::PIC_) {
+    if (!Subtarget->is64Bit() ||
+        M == CodeModel::Small || M == CodeModel::Medium)
+      return dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+
+    return dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
+  }
+
+  if (M == CodeModel::Small || M == CodeModel::Medium)
+    return dwarf::DW_EH_PE_sdata4;
+
+  return dwarf::DW_EH_PE_absptr;
+}
+
 //===----------------------------------------------------------------------===//
 //               Return Value Calling Convention Implementation
 //===----------------------------------------------------------------------===//

lib/Target/X86/X86ISelLowering.h

@@ -560,6 +560,14 @@ namespace llvm {
     /// getFunctionAlignment - Return the Log2 alignment of this function.
     virtual unsigned getFunctionAlignment(const Function *F) const;
 
+    /// getPreferredLSDADataFormat - Return the preferred exception handling data
+    /// format for the LSDA.
+    virtual unsigned getPreferredLSDADataFormat() const;
+
+    /// getPreferredFDEDataFormat - Return the preferred exception handling data
+    /// format for the FDE.
+    virtual unsigned getPreferredFDEDataFormat() const;
+
   private:
     /// Subtarget - Keep a pointer to the X86Subtarget around so that we can
     /// make the right decision when generating code for different targets.