MC: permit emitting a symbol value as section relative

This adds an optional parameter to the EmitSymbolValue method in MCStreamer to
permit emitting a symbol value as a section relative value.  This is to cover
the use in MCDwarf which should not really know about how to emit a section
relative value for a given target.

This addresses post-review comments from Eric Christopher in SVN r213275.

llvm-svn: 213463

2 files changed, 12 insertions, 5 deletions

diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index ae276868198..968cbc96a95 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -655,14 +655,14 @@ static void EmitGenDwarfInfo(MCStreamer *MCOS,
   // The 2 byte DWARF version.
   MCOS->EmitIntValue(context.getDwarfVersion(), 2);
 
+  const MCAsmInfo &AsmInfo = *context.getAsmInfo();
   // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
   // it is at the start of that section so this is zero.
   if (AbbrevSectionSymbol == nullptr)
     MCOS->EmitIntValue(0, 4);
-  else if (context.getAsmInfo()->needsDwarfSectionOffsetDirective())
-    MCOS->EmitCOFFSecRel32(AbbrevSectionSymbol);
   else
-    MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
+    MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4,
+                          AsmInfo.needsDwarfSectionOffsetDirective());
 
   const MCAsmInfo *asmInfo = context.getAsmInfo();
   int AddrSize = asmInfo->getPointerSize();
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index f3564027bf3..46e80cc0c0d 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -148,8 +148,15 @@ void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size,
   EmitValueImpl(Value, Size, Loc);
 }
 
-void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size) {
-  EmitValueImpl(MCSymbolRefExpr::Create(Sym, getContext()), Size);
+void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
+                                 bool IsSectionRelative) {
+  assert((!IsSectionRelative || Size == 4) &&
+         "SectionRelative value requires 4-bytes");
+
+  if (!IsSectionRelative)
+    EmitValueImpl(MCSymbolRefExpr::Create(Sym, getContext()), Size);
+  else
+    EmitCOFFSecRel32(Sym);
 }
 
 void MCStreamer::EmitGPRel64Value(const MCExpr *Value) {