Update llvm/clang to trunk r126547.

There are several bugfixes in this update, but the most important one is
to ensure __start_ and __stop_ symbols for linker sets and kernel module
metadata are always emitted in object files:

  http://llvm.org/bugs/show_bug.cgi?id=9292

Before this fix, if you compiled kernel modules with clang, they would
not be properly processed by kldxref, and if they had any dependencies,
the kernel would fail to load those.  Another problem occurred when
attempting to mount a tmpfs filesystem, which would result in 'operation
not supported by device'.

1 files changed, 25 insertions, 5 deletions

diff --git a/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 0b7bd98..fa311dc 100644
--- a/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -178,6 +178,10 @@ const MCSection *TargetLoweringObjectFileELF::getEHFrameSection() const {
 
 static SectionKind
 getELFKindForNamedSection(StringRef Name, SectionKind K) {
+  // FIXME: Why is this here? Codegen is should not be in the business
+  // of figuring section flags. If the user wrote section(".eh_frame"),
+  // we should just pass that to MC which will defer to the assembly
+  // or use its default if producing an object file.
   if (Name.empty() || Name[0] != '.') return K;
 
   // Some lame default implementation based on some magic section names.
@@ -203,6 +207,9 @@ getELFKindForNamedSection(StringRef Name, SectionKind K) {
       Name.startswith(".llvm.linkonce.tb."))
     return SectionKind::getThreadBSS();
 
+  if (Name == ".eh_frame")
+    return SectionKind::getDataRel();
+
   return K;
 }
 
@@ -441,11 +448,15 @@ void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
 
   Triple T(((LLVMTargetMachine&)TM).getTargetTriple());
   if (T.getOS() == Triple::Darwin) {
-    unsigned MajNum = T.getDarwinMajorNumber();
-    if (MajNum == 7 || MajNum == 8) // 10.3 Panther, 10.4 Tiger
+    switch (T.getDarwinMajorNumber()) {
+    case 7:  // 10.3 Panther.
+    case 8:  // 10.4 Tiger.
       CommDirectiveSupportsAlignment = false;
-    if (MajNum > 9)                 // 10.6 SnowLeopard
-      IsFunctionEHSymbolGlobal = false;
+      break;
+    case 9:   // 10.5 Leopard.
+    case 10:  // 10.6 SnowLeopard.
+      break;
+    }
   }
 
   TargetLoweringObjectFile::Initialize(Ctx, TM);
@@ -630,7 +641,7 @@ getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
                          Mangler *Mang, const TargetMachine &TM) const {
   // Parse the section specifier and create it if valid.
   StringRef Segment, Section;
-  unsigned TAA, StubSize;
+  unsigned TAA = (unsigned)MCSectionMachO::SECTION_ATTRIBUTES, StubSize = 0;
   std::string ErrorCode =
     MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
                                           TAA, StubSize);
@@ -643,10 +654,19 @@ getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
     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)
+    TAA = S->getTypeAndAttributes();
+
   // Okay, now that we got the section, verify that the TAA & StubSize agree.
   // If the user declared multiple globals with different section flags, we need
   // to reject it here.