Emit relocations for DW_AT_location entries on systems which need it. This is

a recommit of r127757. Fixes PR9493. Patch by Paul Robinson!

llvm-svn: 158957

4 files changed, 18 insertions, 13 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index eeacc43c097..2d6dc804635 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1388,13 +1388,14 @@ void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
                                       unsigned Size)
   const {
 
-  // Emit Label+Offset
-  const MCExpr *Plus =
-    MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Label, OutContext),
-                            MCConstantExpr::Create(Offset, OutContext),
-                            OutContext);
-
-  OutStreamer.EmitValue(Plus, 4, 0/*AddrSpace*/);
+  // Emit Label+Offset (or just Label if Offset is zero)
+  const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
+  if (Offset)
+    Expr = MCBinaryExpr::CreateAdd(Expr,
+                                   MCConstantExpr::Create(Offset, OutContext),
+                                   OutContext);
+
+  OutStreamer.EmitValue(Expr, Size, 0/*AddrSpace*/);
 }
 
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 2e24977ef24..1e4ef5fbdbb 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1624,7 +1624,7 @@ void DwarfDebug::emitDIE(DIE *Die) {
       // DW_AT_range Value encodes offset in debug_range section.
       DIEInteger *V = cast<DIEInteger>(Values[i]);
 
-      if (Asm->MAI->doesDwarfUseLabelOffsetForRanges()) {
+      if (Asm->MAI->doesDwarfUseRelocationsAcrossSections()) {
         Asm->EmitLabelPlusOffset(DwarfDebugRangeSectionSym,
                                  V->getValue(),
                                  4);
@@ -1637,10 +1637,14 @@ void DwarfDebug::emitDIE(DIE *Die) {
       break;
     }
     case dwarf::DW_AT_location: {
-      if (DIELabel *L = dyn_cast<DIELabel>(Values[i]))
-        Asm->EmitLabelDifference(L->getValue(), DwarfDebugLocSectionSym, 4);
-      else
+      if (DIELabel *L = dyn_cast<DIELabel>(Values[i])) {
+        if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
+          Asm->EmitLabelReference(L->getValue(), 4);
+        else
+          Asm->EmitLabelDifference(L->getValue(), DwarfDebugLocSectionSym, 4);
+      } else {
         Values[i]->EmitValue(Asm, Form);
+      }
       break;
     }
     case dwarf::DW_AT_accessibility: {
diff --git a/llvm/lib/MC/MCAsmInfo.cpp b/llvm/lib/MC/MCAsmInfo.cpp
index d9c1d51d185..beb20e8f159 100644
--- a/llvm/lib/MC/MCAsmInfo.cpp
+++ b/llvm/lib/MC/MCAsmInfo.cpp
@@ -86,7 +86,7 @@ MCAsmInfo::MCAsmInfo() {
   DwarfUsesInlineInfoSection = false;
   DwarfRequiresRelocationForSectionOffset = true;
   DwarfSectionOffsetDirective = 0;
-  DwarfUsesLabelOffsetForRanges = true;
+  DwarfUsesRelocationsAcrossSections = true;
   DwarfUsesRelocationsForStringPool = true;
   DwarfRegNumForCFI = false;
   HasMicrosoftFastStdCallMangling = false;
diff --git a/llvm/lib/MC/MCAsmInfoDarwin.cpp b/llvm/lib/MC/MCAsmInfoDarwin.cpp
index 73ef7ba0604..7c271a9e824 100644
--- a/llvm/lib/MC/MCAsmInfoDarwin.cpp
+++ b/llvm/lib/MC/MCAsmInfoDarwin.cpp
@@ -60,6 +60,6 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
   HasSymbolResolver = true;
 
   DwarfRequiresRelocationForSectionOffset = false;
-  DwarfUsesLabelOffsetForRanges = false;
+  DwarfUsesRelocationsAcrossSections = false;
   DwarfUsesRelocationsForStringPool = false;
 }