Move Split DWARF handling to an MC option/command line argument rather than using metadata

Since Split DWARF needs to name the actual .dwo file that is generated,
it can't be known at the time the llvm::Module is produced as it may be
merged with other Modules before the object is generated and that object
may be generated with any name.

By passing the Split DWARF file name when LLVM is producing object code
the .dwo file name in the object file can match correctly.

The support for Split DWARF for implicit modules remains the same -
using metadata to store the dwo name and dwo id so that potentially
multiple skeleton CUs referring to different dwo files can be generated
from one llvm::Module.

llvm-svn: 301062

1 files changed, 4 insertions, 15 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d72656bcc58..6f442f5c317 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -91,14 +91,6 @@ DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
                  cl::init(Default));
 
 static cl::opt<DefaultOnOff>
-SplitDwarf("split-dwarf", cl::Hidden,
-           cl::desc("Output DWARF5 split debug info."),
-           cl::values(clEnumVal(Default, "Default for platform"),
-                      clEnumVal(Enable, "Enabled"),
-                      clEnumVal(Disable, "Disabled")),
-           cl::init(Default));
-
-static cl::opt<DefaultOnOff>
 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
                  cl::desc("Generate DWARF pubnames and pubtypes sections"),
                  cl::values(clEnumVal(Default, "Default for platform"),
@@ -253,11 +245,8 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
 
   HasAppleExtensionAttributes = tuneForLLDB();
 
-  // Handle split DWARF. Off by default for now.
-  if (SplitDwarf == Default)
-    HasSplitDwarf = false;
-  else
-    HasSplitDwarf = SplitDwarf == Enable;
+  // Handle split DWARF.
+  HasSplitDwarf = !Asm->TM.Options.MCOptions.SplitDwarfFile.empty();
 
   // Pubnames/pubtypes on by default for GDB.
   if (DwarfPubSections == Default)
@@ -412,7 +401,7 @@ DwarfDebug::constructDwarfCompileUnit(const DICompileUnit *DIUnit) {
   if (useSplitDwarf()) {
     NewCU.setSkeleton(constructSkeletonCU(NewCU));
     NewCU.addString(Die, dwarf::DW_AT_GNU_dwo_name,
-                    DIUnit->getSplitDebugFilename());
+                  Asm->TM.Options.MCOptions.SplitDwarfFile);
   }
 
   // LTO with assembly output shares a single line table amongst multiple CUs.
@@ -1885,7 +1874,7 @@ void DwarfDebug::emitDebugMacinfo() {
 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
                                   std::unique_ptr<DwarfCompileUnit> NewU) {
   NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
-                  U.getCUNode()->getSplitDebugFilename());
+                  Asm->TM.Options.MCOptions.SplitDwarfFile);
 
   if (!CompilationDir.empty())
     NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);