DwarfUnit: Refactor out DW_AT_stmt_list creation into common function for fission and non-fission cases

This probably also addresses the FIXME in the fission case regarding
multiple compile units, though I haven't tested that.

This code still confuses me (the literal zero offset makes little sense,
the limitations surrounding asm output I'm not sure about either - but
perhaps we should just always emit one line table? Or should we not rely
on .loc/.file even in assembly so we can produce the same output between
asm and object output?) but this maintains the existing functionality.

llvm-svn: 201441

3 files changed, 31 insertions, 30 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 4d0eb445d34..4c5fe2ecb99 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -762,31 +762,9 @@ DwarfCompileUnit *DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
                  DIUnit.getLanguage());
   NewCU->addString(Die, dwarf::DW_AT_name, FN);
 
-  // Define start line table label for each Compile Unit.
-  MCSymbol *LineTableStartSym =
-      Asm->GetTempSymbol("line_table_start", NewCU->getUniqueID());
-  Asm->OutStreamer.getContext().setMCLineTableSymbol(LineTableStartSym,
-                                                     NewCU->getUniqueID());
-
-  // Use a single line table if we are generating assembly.
-  bool UseTheFirstCU =
-      Asm->OutStreamer.hasRawTextSupport() || (NewCU->getUniqueID() == 0);
 
   if (!useSplitDwarf()) {
-    // DW_AT_stmt_list is a offset of line number information for this
-    // compile unit in debug_line section. For split dwarf this is
-    // left in the skeleton CU and so not included.
-    // The line table entries are not always emitted in assembly, so it
-    // is not okay to use line_table_start here.
-    if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-      NewCU->addSectionLabel(Die, dwarf::DW_AT_stmt_list,
-                             UseTheFirstCU ? DwarfLineSectionSym
-                                           : LineTableStartSym);
-    else if (UseTheFirstCU)
-      NewCU->addSectionOffset(Die, dwarf::DW_AT_stmt_list, 0);
-    else
-      NewCU->addSectionDelta(Die, dwarf::DW_AT_stmt_list, LineTableStartSym,
-                             DwarfLineSectionSym);
+    NewCU->initStmtList(DwarfLineSectionSym);
 
     // If we're using split dwarf the compilation dir is going to be in the
     // skeleton CU and so we don't need to duplicate it here.
@@ -2956,13 +2934,7 @@ DwarfCompileUnit *DwarfDebug::constructSkeletonCU(const DwarfCompileUnit *CU) {
   NewCU->initSection(Asm->getObjFileLowering().getDwarfInfoSection(),
                      DwarfInfoSectionSym);
 
-  // DW_AT_stmt_list is a offset of line number information for this
-  // compile unit in debug_line section.
-  // FIXME: Should handle multiple compile units.
-  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-    NewCU->addSectionLabel(Die, dwarf::DW_AT_stmt_list, DwarfLineSectionSym);
-  else
-    NewCU->addSectionOffset(Die, dwarf::DW_AT_stmt_list, 0);
+  NewCU->initStmtList(DwarfLineSectionSym);
 
   initSkeletonUnit(CU, Die, NewCU);
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index db354e6f161..57e8abe04c0 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1981,6 +1981,33 @@ void DwarfUnit::emitHeader(const MCSection *ASection,
 }
 
 DwarfCompileUnit::~DwarfCompileUnit() {}
+
+void DwarfCompileUnit::initStmtList(MCSymbol *DwarfLineSectionSym) {
+  // Define start line table label for each Compile Unit.
+  MCSymbol *LineTableStartSym =
+      Asm->GetTempSymbol("line_table_start", getUniqueID());
+  Asm->OutStreamer.getContext().setMCLineTableSymbol(LineTableStartSym,
+                                                     getUniqueID());
+
+  // Use a single line table if we are generating assembly.
+  bool UseTheFirstCU =
+      Asm->OutStreamer.hasRawTextSupport() || (getUniqueID() == 0);
+
+  // DW_AT_stmt_list is a offset of line number information for this
+  // compile unit in debug_line section. For split dwarf this is
+  // left in the skeleton CU and so not included.
+  // The line table entries are not always emitted in assembly, so it
+  // is not okay to use line_table_start here.
+  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
+    addSectionLabel(UnitDie.get(), dwarf::DW_AT_stmt_list,
+                    UseTheFirstCU ? DwarfLineSectionSym : LineTableStartSym);
+  else if (UseTheFirstCU)
+    addSectionOffset(UnitDie.get(), dwarf::DW_AT_stmt_list, 0);
+  else
+    addSectionDelta(UnitDie.get(), dwarf::DW_AT_stmt_list, LineTableStartSym,
+                    DwarfLineSectionSym);
+}
+
 DwarfTypeUnit::~DwarfTypeUnit() {}
 
 void DwarfTypeUnit::emitHeader(const MCSection *ASection,
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index 60e86c5d828..4eabeaf00fd 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -544,6 +544,8 @@ public:
                    DwarfDebug *DW, DwarfFile *DWU);
   virtual ~DwarfCompileUnit() LLVM_OVERRIDE;
 
+  void initStmtList(MCSymbol *DwarfLineSectionSym);
+
   /// createGlobalVariableDIE - create global variable DIE.
   void createGlobalVariableDIE(DIGlobalVariable GV);