[llvm] r207321 - DwarfDebug: Minor refactoring around type unit construction

[David Blaikie]

Author: dblaikie
Date: Sat Apr 26 11:26:41 2014
New Revision: 207321

URL: http://llvm.org/viewvc/llvm-project?rev=207321&view=rev
Log:
DwarfDebug: Minor refactoring around type unit construction

Sinking addition of the declaration attribute down to where the
signature is added. So that if the signature is not added neither is the
declaration attribute (this will come in handy when aborting type unit
construction to instead emit the type into the CU directly in some
cases)

Pull out type unit identifier hashing just to simplify the function a
little, it'll be getting longer.

Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=207321&r1=207320&r2=207321&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Sat Apr 26 11:26:41 2014
@@ -2486,15 +2486,20 @@ MCDwarfDwoLineTable *DwarfDebug::getDwoL
   return &SplitTypeUnitFileTable;
 }
 
+static uint64_t makeTypeSignature(StringRef Identifier) {
+  MD5 Hash;
+  Hash.update(Identifier);
+  // ... take the least significant 8 bytes and return those. Our MD5
+  // implementation always returns its results in little endian, swap bytes
+  // appropriately.
+  MD5::MD5Result Result;
+  Hash.final(Result);
+  return *reinterpret_cast<support::ulittle64_t *>(Result + 8);
+}
+
 void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
                                       StringRef Identifier, DIE &RefDie,
                                       DICompositeType CTy) {
-  // Flag the type unit reference as a declaration so that if it contains
-  // members (implicit special members, static data member definitions, member
-  // declarations for definitions in this CU, etc) consumers don't get confused
-  // and think this is a full definition.
-  CU.addFlag(RefDie, dwarf::DW_AT_declaration);
-
   const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
   if (TU) {
     CU.addDIETypeSignature(RefDie, *TU);
@@ -2512,27 +2517,21 @@ void DwarfDebug::addDwarfTypeUnitType(Dw
   NewTU.addUInt(*UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
                 CU.getLanguage());
 
-  MD5 Hash;
-  Hash.update(Identifier);
-  // ... take the least significant 8 bytes and return those. Our MD5
-  // implementation always returns its results in little endian, swap bytes
-  // appropriately.
-  MD5::MD5Result Result;
-  Hash.final(Result);
-  uint64_t Signature = *reinterpret_cast<support::ulittle64_t *>(Result + 8);
+  uint64_t Signature = makeTypeSignature(Identifier);
   NewTU.setTypeSignature(Signature);
+
   if (useSplitDwarf())
     NewTU.setSkeleton(constructSkeletonTU(NewTU));
   else
     CU.applyStmtList(*UnitDie);
 
-  NewTU.setType(NewTU.createTypeDIE(CTy));
-
   NewTU.initSection(
       useSplitDwarf()
           ? Asm->getObjFileLowering().getDwarfTypesDWOSection(Signature)
           : Asm->getObjFileLowering().getDwarfTypesSection(Signature));
 
+  NewTU.setType(NewTU.createTypeDIE(CTy));
+
   CU.addDIETypeSignature(RefDie, NewTU);
 }
 

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=207321&r1=207320&r2=207321&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Sat Apr 26 11:26:41 2014
@@ -360,6 +360,12 @@ void DwarfUnit::addDIEEntry(DIE &Die, dw
 }
 
 void DwarfUnit::addDIETypeSignature(DIE &Die, const DwarfTypeUnit &Type) {
+  // Flag the type unit reference as a declaration so that if it contains
+  // members (implicit special members, static data member definitions, member
+  // declarations for definitions in this CU, etc) consumers don't get confused
+  // and think this is a full definition.
+  addFlag(Die, dwarf::DW_AT_declaration);
+
   Die.addValue(dwarf::DW_AT_signature, dwarf::DW_FORM_ref_sig8,
                new (DIEValueAllocator) DIETypeSignature(Type));
 }