From: David Blaikie <dblaikie@gmail.com>
Date: Mon, 3 Nov 2014 21:15:30 +0000 (+0000)
Subject: Add DwarfCompileUnit::BaseAddress to track the base address used by relative addressi... 
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=dc1d16ae54aceebdecc7262b2ef806387f98ace3;p=oota-llvm.git

Add DwarfCompileUnit::BaseAddress to track the base address used by relative addressing in debug_ranges and debug_loc

This is one of a few steps to generalize range handling to include the
CU range (thus the CU's range list will be moved into the range list
list, losing track of the base address in the process), which means
generalizing ranges from both the skeleton and full unit under fission.

And... then I can used that generalized support for ranges in
fission+gmlt where there'll be a bunch more ranges in the skeleton.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221182 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 706ea100e0c..714043d0be6 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/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) {
+      Skeleton(nullptr), LabelBegin(nullptr), BaseAddress(nullptr) {
   insertDIE(Node, &getUnitDie());
 }
 
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 787ac23eb03..27cfdcdaa48 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -55,6 +55,10 @@ class DwarfCompileUnit : public DwarfUnit {
   // List of ranges for a given compile unit.
   SmallVector<RangeSpan, 1> CURanges;
 
+  // The base address of this unit, if any. Used for relative references in
+  // ranges/locs.
+  const MCSymbol *BaseAddress;
+
   /// \brief Construct a DIE for the given DbgVariable without initializing the
   /// DbgVariable's DIE reference.
   std::unique_ptr<DIE> constructVariableDIEImpl(const DbgVariable &DV,
@@ -233,6 +237,9 @@ public:
 
   /// getRanges - Get the list of ranges for this unit.
   const SmallVectorImpl<RangeSpan> &getRanges() const { return CURanges; }
+
+  void setBaseAddress(const MCSymbol *Base) { BaseAddress = Base; }
+  const MCSymbol *getBaseAddress() const { return BaseAddress; }
 };
 
 } // end llvm namespace
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 2b432c035cb..95dedb5549b 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -592,6 +592,7 @@ void DwarfDebug::finalizeModuleInfo() {
         U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
       } else {
         const RangeSpan &Range = TheCU.getRanges().back();
+        TheCU.setBaseAddress(Range.getStart());
         U.attachLowHighPC(U.getUnitDie(), Range.getStart(), Range.getEnd());
       }
     }
@@ -1791,9 +1792,7 @@ void DwarfDebug::emitDebugLoc() {
       // Set up the range. This range is relative to the entry point of the
       // compile unit. This is a hard coded 0 for low_pc when we're emitting
       // ranges, or the DW_AT_low_pc on the compile unit otherwise.
-      if (CU->getRanges().size() == 1) {
-        // Grab the begin symbol from the first range as our base.
-        const MCSymbol *Base = CU->getRanges()[0].getStart();
+      if (auto *Base = CU->getBaseAddress()) {
         Asm->EmitLabelDifference(Entry.getBeginSym(), Base, Size);
         Asm->EmitLabelDifference(Entry.getEndSym(), Base, Size);
       } else {
@@ -2003,9 +2002,7 @@ void DwarfDebug::emitDebugRanges() {
         const MCSymbol *End = Range.getEnd();
         assert(Begin && "Range without a begin symbol?");
         assert(End && "Range without an end symbol?");
-        if (TheCU->getRanges().size() == 1) {
-          // Grab the begin symbol from the first range as our base.
-          const MCSymbol *Base = TheCU->getRanges()[0].getStart();
+        if (auto *Base = TheCU->getBaseAddress()) {
           Asm->EmitLabelDifference(Begin, Base, Size);
           Asm->EmitLabelDifference(End, Base, Size);
         } else {