Store an optional section start label in MCSection.

This makes code that uses section relative expressions (debug info) simpler and
less brittle.

This is still a bit awkward as the symbol is created late and has to be
stored in a mutable field.

I will move the symbol creation earlier in the next patch.

llvm-svn: 231802

1 files changed, 10 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 85649492e23..85a6f117caa 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -19,7 +19,7 @@ DwarfCompileUnit::DwarfCompileUnit(unsigned UID, DICompileUnit Node,
                                    AsmPrinter *A, DwarfDebug *DW,
                                    DwarfFile *DWU)
     : DwarfUnit(UID, dwarf::DW_TAG_compile_unit, Node, A, DW, DWU),
-      Skeleton(nullptr), LabelBegin(nullptr), BaseAddress(nullptr) {
+      Skeleton(nullptr), BaseAddress(nullptr) {
   insertDIE(Node, &getUnitDie());
 }
 
@@ -245,7 +245,7 @@ void DwarfCompileUnit::addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
     addSectionDelta(Die, Attribute, Label, Sec);
 }
 
-void DwarfCompileUnit::initStmtList(MCSymbol *DwarfLineSectionSym) {
+void DwarfCompileUnit::initStmtList() {
   // Define start line table label for each Compile Unit.
   MCSymbol *LineTableStartSym =
       Asm->OutStreamer.getDwarfLineTableSymbol(getUniqueID());
@@ -257,8 +257,9 @@ void DwarfCompileUnit::initStmtList(MCSymbol *DwarfLineSectionSym) {
   // 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.
+  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
   addSectionLabel(UnitDie, dwarf::DW_AT_stmt_list, LineTableStartSym,
-                  DwarfLineSectionSym);
+                  TLOF.getDwarfLineSection()->getBeginSymbol());
 }
 
 void DwarfCompileUnit::applyStmtList(DIE &D) {
@@ -380,9 +381,12 @@ void DwarfCompileUnit::addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
 
 void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
                                          SmallVector<RangeSpan, 2> Range) {
+  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+
   // Emit offset in .debug_range as a relocatable label. emitDIE will handle
   // emitting it appropriately.
-  auto *RangeSectionSym = DD->getRangeSectionSym();
+  const MCSymbol *RangeSectionSym =
+      TLOF.getDwarfRangesSection()->getBeginSymbol();
 
   RangeSpanList List(
       Asm->GetTempSymbol("debug_ranges", DD->getNextRangeNumber()),
@@ -711,14 +715,14 @@ void DwarfCompileUnit::collectDeadVariables(DISubprogram SP) {
   }
 }
 
-void DwarfCompileUnit::emitHeader(const MCSymbol *ASectionSym) {
+void DwarfCompileUnit::emitHeader(bool UseOffsets) {
   // Don't bother labeling the .dwo unit, as its offset isn't used.
   if (!Skeleton) {
     LabelBegin = Asm->createTempSymbol("cu_begin", getUniqueID());
     Asm->OutStreamer.EmitLabel(LabelBegin);
   }
 
-  DwarfUnit::emitHeader(ASectionSym);
+  DwarfUnit::emitHeader(UseOffsets);
 }
 
 /// addGlobalName - Add a new global name to the compile unit.