Add an EmitAbsValue helper method and use it in cases where we want to be sure

that no relocations are used (on MochO).
Fixes llc producing different output from llc + llvm-mc.

llvm-svn: 121000

4 files changed, 14 insertions, 10 deletions

diff --git a/llvm/include/llvm/MC/MCStreamer.h b/llvm/include/llvm/MC/MCStreamer.h
index d89ee9ae126..fce076a57eb 100644
--- a/llvm/include/llvm/MC/MCStreamer.h
+++ b/llvm/include/llvm/MC/MCStreamer.h
@@ -249,6 +249,11 @@ namespace llvm {
     virtual void EmitIntValue(uint64_t Value, unsigned Size,
                               unsigned AddrSpace = 0);
 
+    /// EmitAbsValue - Emit the Value, but try to avoid relocations. On MachO
+    /// this is done by producing
+    /// foo = value
+    /// .long foo
+    void EmitAbsValue(const MCExpr *Value, unsigned Size);
 
     virtual void EmitULEB128Value(const MCExpr *Value,
                                   unsigned AddrSpace = 0) = 0;
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
index f737e90b155..1f7ac95f7b3 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
@@ -156,7 +156,7 @@ void AsmPrinter::EmitReference(const MCSymbol *Sym, unsigned Encoding) const {
   
   const MCExpr *Exp =
     TLOF.getExprForDwarfReference(Sym, Mang, MMI, Encoding, OutStreamer);
-  OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding), /*addrspace*/0);
+  OutStreamer.EmitAbsValue(Exp, GetSizeOfEncodedValue(Encoding));
 }
 
 void AsmPrinter::EmitReference(const GlobalValue *GV, unsigned Encoding)const{
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index 53731dca7eb..5d36ee3e626 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -213,15 +213,8 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS,
 
   // The first 4 bytes is the total length of the information for this
   // compilation unit (not including these 4 bytes for the length).
-  // FIXME: We create the dummy TotalLength variable because LineEndSym points
-  // to the end of the section and the darwin assembler doesn't consider that
-  // difference an assembly time constant. It might be better for this to be
-  // proected by a flag.
-  MCSymbol *TotalLength = MCOS->getContext().CreateTempSymbol();
-  MCOS->EmitAssignment(TotalLength,
-		       MakeStartMinusEndExpr(MCOS, LineStartSym, LineEndSym,
-					     4));
-  MCOS->EmitSymbolValue(TotalLength, 4, 0);
+  MCOS->EmitAbsValue(MakeStartMinusEndExpr(MCOS, LineStartSym, LineEndSym,4),
+                     4);
 
   // Next 2 bytes is the Version, which is Dwarf 2.
   MCOS->EmitIntValue(2, 2);
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 6df4ae44e40..b9d59056f3b 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -72,6 +72,12 @@ void MCStreamer::EmitSLEB128IntValue(int64_t Value, unsigned AddrSpace) {
   EmitBytes(OSE.str(), AddrSpace);
 }
 
+void MCStreamer::EmitAbsValue(const MCExpr *Value, unsigned Size) {
+  MCSymbol *ABS = getContext().CreateTempSymbol();
+  EmitAssignment(ABS, Value);
+  EmitSymbolValue(ABS, Size, 0);
+}
+
 void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
                                  unsigned AddrSpace) {
   EmitValue(MCSymbolRefExpr::Create(Sym, getContext()), Size, AddrSpace);