Next step: Only pad debug_line when the target is darwin. Add a FIXME to avoid

doing that if the target is darwin10 or newer.

This fixes
*) Direct object emission was producing objects without the workaround on
   darwin9.
*) Assembly printing was producing objects with the workaround on linux.

llvm-svn: 120866

4 files changed, 9 insertions, 5 deletions

diff --git a/llvm/lib/MC/MCAsmInfo.cpp b/llvm/lib/MC/MCAsmInfo.cpp
index 37444c9c256..9cf4019e312 100644
--- a/llvm/lib/MC/MCAsmInfo.cpp
+++ b/llvm/lib/MC/MCAsmInfo.cpp
@@ -23,6 +23,7 @@ MCAsmInfo::MCAsmInfo() {
   HasMachoZeroFillDirective = false;
   HasMachoTBSSDirective = false;
   HasStaticCtorDtorReferenceInStaticMode = false;
+  LinkerRequiresNonEmptyDwarfLines = false;
   MaxInstLength = 4;
   PCSymbol = "$";
   SeparatorChar = ';';
diff --git a/llvm/lib/MC/MCAsmInfoDarwin.cpp b/llvm/lib/MC/MCAsmInfoDarwin.cpp
index fd155135df0..1147f02a596 100644
--- a/llvm/lib/MC/MCAsmInfoDarwin.cpp
+++ b/llvm/lib/MC/MCAsmInfoDarwin.cpp
@@ -37,6 +37,9 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
   HasMachoZeroFillDirective = true;  // Uses .zerofill
   HasMachoTBSSDirective = true; // Uses .tbss
   HasStaticCtorDtorReferenceInStaticMode = true;
+
+  // FIXME: Darwin 10 and newer don't need this.
+  LinkerRequiresNonEmptyDwarfLines = true;
   
   HiddenVisibilityAttr = MCSA_PrivateExtern;
   // Doesn't support protected visibility.
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 7189a90406e..40a234ea85f 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -896,8 +896,7 @@ void MCAsmStreamer::EmitRawText(StringRef String) {
 void MCAsmStreamer::Finish() {
   // Dump out the dwarf file & directory tables and line tables.
   if (getContext().hasDwarfFiles() && TLOF)
-    MCDwarfFileTable::Emit(this, TLOF->getDwarfLineSection(),
-                           TLOF->getTextSection());
+    MCDwarfFileTable::Emit(this, TLOF->getDwarfLineSection());
 }
 
 MCStreamer *llvm::createAsmStreamer(MCContext &Context,
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index 194c324ab6c..a33b0c596ba 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCStreamer.h"
@@ -198,8 +199,7 @@ static inline void EmitDwarfLineTable(MCStreamer *MCOS,
 // This emits the Dwarf file and the line tables.
 //
 void MCDwarfFileTable::Emit(MCStreamer *MCOS,
-                            const MCSection *DwarfLineSection,
-                            const MCSection *TextSection) {
+                            const MCSection *DwarfLineSection) {
   // Switch to the section where the table will be emitted into.
   MCOS->SwitchSection(DwarfLineSection);
 
@@ -296,7 +296,8 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS,
     delete Line;
   }
 
-  if (TextSection && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
+  if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
+      && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
     // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
     // it requires:  
     // total_length >= prologue_length + 10