Add support to emit dwarf ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101575 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/AsmPrinter.h

@@ -333,6 +333,12 @@ namespace llvm {
     void EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
                              unsigned Size) const;
     
+    /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo" 
+    /// where the size in bytes of the directive is specified by Size and Hi/Lo
+    /// specify the labels.  This implicitly uses .set if it is available.
+    void EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
+                                   const MCSymbol *Lo, unsigned Size) const;
+    
     //===------------------------------------------------------------------===//
     // Dwarf Emission Helper Routines
     //===------------------------------------------------------------------===//

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -1094,6 +1094,36 @@ void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
   OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
 }
 
+/// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo" 
+/// where the size in bytes of the directive is specified by Size and Hi/Lo
+/// specify the labels.  This implicitly uses .set if it is available.
+void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
+                                           const MCSymbol *Lo, unsigned Size) 
+  const {
+  
+  // Emit Hi+Offset - Lo
+  // Get the Hi+Offset expression.
+  const MCExpr *Plus =
+    MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext), 
+                            MCConstantExpr::Create(Offset, OutContext),
+                            OutContext);
+  
+  // Get the Hi+Offset-Lo expression.
+  const MCExpr *Diff = 
+    MCBinaryExpr::CreateSub(Plus,
+                            MCSymbolRefExpr::Create(Lo, OutContext),
+                            OutContext);
+  
+  if (!MAI->hasSetDirective()) 
+    OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
+  else {
+    // Otherwise, emit with .set (aka assignment).
+    MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
+    OutStreamer.EmitAssignment(SetLabel, Diff);
+    OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
+  }
+}
+    
 
 //===----------------------------------------------------------------------===//
 

lib/CodeGen/AsmPrinter/DIE.h

@@ -261,11 +261,12 @@ namespace llvm {
     ///
     virtual void EmitValue(AsmPrinter *AP, unsigned Form) const;
 
+    uint64_t getValue() const { return Integer; }
+
     /// SizeOf - Determine size of integer value in bytes.
     ///
     virtual unsigned SizeOf(AsmPrinter *AP, unsigned Form) const;
 
-
     // Implement isa/cast/dyncast.
     static bool classof(const DIEInteger *) { return true; }
     static bool classof(const DIEValue *I) { return I->getType() == isInteger; }

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -302,7 +302,7 @@ DbgScope::~DbgScope() {
 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   : Asm(A), MMI(Asm->MMI), ModuleCU(0),
     AbbreviationsSet(InitAbbreviationsSetSize), 
-    CurrentFnDbgScope(0) {
+    CurrentFnDbgScope(0), PrevLabel(NULL) {
   NextStringPoolNumber = 0;
       
   DwarfFrameSectionSym = DwarfInfoSectionSym = DwarfAbbrevSectionSym = 0;
@@ -2354,6 +2354,7 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
   InsnBeforeLabelMap.clear();
   InsnAfterLabelMap.clear();
   Lines.clear();
+  PrevLabel = NULL;
 }
 
 /// recordSourceLine - Register a source line with debug info. Returns the
@@ -2490,7 +2491,8 @@ void DwarfDebug::EmitSectionLabels() {
   EmitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
   DwarfStrSectionSym = 
     EmitSectionSym(Asm, TLOF.getDwarfStrSection(), "section_str");
-  EmitSectionSym(Asm, TLOF.getDwarfRangesSection());
+  DwarfDebugRangeSectionSym = EmitSectionSym(Asm, TLOF.getDwarfRangesSection(),
+                                             "debug_range");
 
   TextSectionSym = EmitSectionSym(Asm, TLOF.getTextSection(), "text_begin");
   EmitSectionSym(Asm, TLOF.getDataSection());
@@ -2534,6 +2536,15 @@ void DwarfDebug::emitDIE(DIE *Die) {
       Asm->EmitInt32(Addr);
       break;
     }
+    case dwarf::DW_AT_ranges: {
+      // DW_AT_range Value encodes offset in debug_range section.
+      DIEInteger *V = cast<DIEInteger>(Values[i]);
+      Asm->EmitLabelOffsetDifference(DwarfDebugRangeSectionSym,
+                                     V->getValue(),
+                                     DwarfDebugRangeSectionSym,
+                                     4);
+      break;
+    }
     default:
       // Emit an attribute using the defined form.
       Values[i]->EmitValue(Asm, Form);
@@ -3055,7 +3066,16 @@ void DwarfDebug::EmitDebugARanges() {
 void DwarfDebug::emitDebugRanges() {
   // Start the dwarf ranges section.
   Asm->OutStreamer.SwitchSection(
-                            Asm->getObjFileLowering().getDwarfRangesSection());
+    Asm->getObjFileLowering().getDwarfRangesSection());
+  for (SmallVector<const MCSymbol *, 8>::const_iterator I = DebugRangeSymbols.begin(),
+         E = DebugRangeSymbols.end(); I != E; ++I) {
+    if (*I) 
+      Asm->EmitLabelDifference(*I, TextSectionSym,
+                               Asm->getTargetData().getPointerSize());
+    else
+      Asm->OutStreamer.EmitIntValue(0, Asm->getTargetData().getPointerSize(), 
+                                    /*addrspace*/0);
+  }
 }
 
 /// emitDebugMacInfo - Emit visible names into a debug macinfo section.

lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -196,9 +196,12 @@ class DwarfDebug {
   /// instruction.
   DenseMap<const MachineInstr *, MCSymbol *> InsnAfterLabelMap;
 
+  SmallVector<const MCSymbol *, 8> DebugRangeSymbols;
+
   /// Previous instruction's location information. This is used to determine
   /// label location to indicate scope boundries in dwarf debug info.
   DebugLoc PrevInstLoc;
+  MCSymbol *PrevLabel;
 
   struct FunctionDebugFrameInfo {
     unsigned Number;
@@ -214,7 +217,7 @@ class DwarfDebug {
   // the beginning of each supported dwarf section.  These are used to form
   // section offsets and are created by EmitSectionLabels.
   MCSymbol *DwarfFrameSectionSym, *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
-  MCSymbol *DwarfStrSectionSym, *TextSectionSym;
+  MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
   
 private: