MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release.  This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
   SVN      git
  181387  779e6ac
  181703  7bef4e2
  182099  b31044e
  182650  f2dcf35
  182683  0d91b80
  183862  15c1774
  183929  99447a6
  184177  0b2934b
  184948  4dc3761
  184954  007e7bc
  186990  eebd175

Sponsored by:	DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge.  The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

  Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by:	jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

  Don't produce an alias between destructors with different calling conventions.

  Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by:	multiple users on freebsd-current
PR:		bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by:	rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp.  This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all.  These directories are now only used
if you pass -stdlib=libstdc++.

1 files changed, 13 insertions, 6 deletions

diff --git a/contrib/llvm/lib/CodeGen/BranchFolding.cpp b/contrib/llvm/lib/CodeGen/BranchFolding.cpp
index f8cc3b3..9cd4208 100644
--- a/contrib/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/contrib/llvm/lib/CodeGen/BranchFolding.cpp
@@ -135,8 +135,8 @@ bool BranchFolder::OptimizeImpDefsBlock(MachineBasicBlock *MBB) {
     if (!I->isImplicitDef())
       break;
     unsigned Reg = I->getOperand(0).getReg();
-    ImpDefRegs.insert(Reg);
-    for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+    for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
+         SubRegs.isValid(); ++SubRegs)
       ImpDefRegs.insert(*SubRegs);
     ++I;
   }
@@ -406,7 +406,8 @@ void BranchFolder::ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
 /// MBB so that the part before the iterator falls into the part starting at the
 /// iterator.  This returns the new MBB.
 MachineBasicBlock *BranchFolder::SplitMBBAt(MachineBasicBlock &CurMBB,
-                                            MachineBasicBlock::iterator BBI1) {
+                                            MachineBasicBlock::iterator BBI1,
+                                            const BasicBlock *BB) {
   if (!TII->isLegalToSplitMBBAt(CurMBB, BBI1))
     return 0;
 
@@ -414,7 +415,7 @@ MachineBasicBlock *BranchFolder::SplitMBBAt(MachineBasicBlock &CurMBB,
 
   // Create the fall-through block.
   MachineFunction::iterator MBBI = &CurMBB;
-  MachineBasicBlock *NewMBB =MF.CreateMachineBasicBlock(CurMBB.getBasicBlock());
+  MachineBasicBlock *NewMBB =MF.CreateMachineBasicBlock(BB);
   CurMBB.getParent()->insert(++MBBI, NewMBB);
 
   // Move all the successors of this block to the specified block.
@@ -647,6 +648,7 @@ void BranchFolder::RemoveBlocksWithHash(unsigned CurHash,
 /// CreateCommonTailOnlyBlock - None of the blocks to be tail-merged consist
 /// only of the common tail.  Create a block that does by splitting one.
 bool BranchFolder::CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB,
+                                             MachineBasicBlock *SuccBB,
                                              unsigned maxCommonTailLength,
                                              unsigned &commonTailIndex) {
   commonTailIndex = 0;
@@ -676,7 +678,12 @@ bool BranchFolder::CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB,
   DEBUG(dbgs() << "\nSplitting BB#" << MBB->getNumber() << ", size "
                << maxCommonTailLength);
 
-  MachineBasicBlock *newMBB = SplitMBBAt(*MBB, BBI);
+  // If the split block unconditionally falls-thru to SuccBB, it will be
+  // merged. In control flow terms it should then take SuccBB's name. e.g. If
+  // SuccBB is an inner loop, the common tail is still part of the inner loop.
+  const BasicBlock *BB = (SuccBB && MBB->succ_size() == 1) ?
+    SuccBB->getBasicBlock() : MBB->getBasicBlock();
+  MachineBasicBlock *newMBB = SplitMBBAt(*MBB, BBI, BB);
   if (!newMBB) {
     DEBUG(dbgs() << "... failed!");
     return false;
@@ -784,7 +791,7 @@ bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB,
          !SameTails[commonTailIndex].tailIsWholeBlock())) {
       // None of the blocks consist entirely of the common tail.
       // Split a block so that one does.
-      if (!CreateCommonTailOnlyBlock(PredBB,
+      if (!CreateCommonTailOnlyBlock(PredBB, SuccBB,
                                      maxCommonTailLength, commonTailIndex)) {
         RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
         continue;