Reapply 127939 since Daniel fixed the breakage.  <rdar://problem/9012638>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127944 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index fa311dc..f332d12 100644
--- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -641,10 +641,11 @@
                          Mangler *Mang, const TargetMachine &TM) const {
   // Parse the section specifier and create it if valid.
   StringRef Segment, Section;
-  unsigned TAA = (unsigned)MCSectionMachO::SECTION_ATTRIBUTES, StubSize = 0;
+  unsigned TAA = 0, StubSize = 0;
+  bool TAAParsed;
   std::string ErrorCode =
     MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
-                                          TAA, StubSize);
+                                          TAA, TAAParsed, StubSize);
   if (!ErrorCode.empty()) {
     // If invalid, report the error with report_fatal_error.
     report_fatal_error("Global variable '" + GV->getNameStr() +
@@ -654,17 +655,13 @@
     return DataSection;
   }
 
-  bool TAAWasSet = (TAA != MCSectionMachO::SECTION_ATTRIBUTES);
-  if (!TAAWasSet)
-    TAA = 0;      // Sensible default if this is a new section.
-    
   // Get the section.
   const MCSectionMachO *S =
     getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
 
   // If TAA wasn't set by ParseSectionSpecifier() above,
   // use the value returned by getMachOSection() as a default.
-  if (!TAAWasSet)
+  if (!TAAParsed)
     TAA = S->getTypeAndAttributes();
 
   // Okay, now that we got the section, verify that the TAA & StubSize agree.
diff --git a/lib/MC/MCParser/DarwinAsmParser.cpp b/lib/MC/MCParser/DarwinAsmParser.cpp
index f01f866..3c092cd 100644
--- a/lib/MC/MCParser/DarwinAsmParser.cpp
+++ b/lib/MC/MCParser/DarwinAsmParser.cpp
@@ -435,10 +435,11 @@
 
   StringRef Segment, Section;
   unsigned StubSize;
-  unsigned TAA = 0;
+  unsigned TAA;
+  bool TAAParsed;
   std::string ErrorStr =
     MCSectionMachO::ParseSectionSpecifier(SectionSpec, Segment, Section,
-                                          TAA, StubSize);
+                                          TAA, TAAParsed, StubSize);
 
   if (!ErrorStr.empty())
     return Error(Loc, ErrorStr.c_str());
diff --git a/lib/MC/MCSectionMachO.cpp b/lib/MC/MCSectionMachO.cpp
index 577e93a..e771556 100644
--- a/lib/MC/MCSectionMachO.cpp
+++ b/lib/MC/MCSectionMachO.cpp
@@ -180,7 +180,9 @@
                                                   StringRef &Segment,    // Out.
                                                   StringRef &Section,    // Out.
                                                   unsigned  &TAA,        // Out.
+                                                  bool      &TAAParsed,  // Out.
                                                   unsigned  &StubSize) { // Out.
+  TAAParsed = false;
   // Find the first comma.
   std::pair<StringRef, StringRef> Comma = Spec.split(',');
 
@@ -211,6 +213,7 @@
            "between 1 and 16 characters";
 
   // If there is no comma after the section, we're done.
+  TAA = 0;
   StubSize = 0;
   if (Comma.second.empty())
     return "";
@@ -235,6 +238,7 @@
 
   // Remember the TypeID.
   TAA = TypeID;
+  TAAParsed = true;
 
   // If we have no comma after the section type, there are no attributes.
   if (Comma.second.empty()) {