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, 245 insertions, 0 deletions

diff --git a/contrib/llvm/lib/Analysis/CFG.cpp b/contrib/llvm/lib/Analysis/CFG.cpp
new file mode 100644
index 0000000..c3f32d3
--- /dev/null
+++ b/contrib/llvm/lib/Analysis/CFG.cpp
@@ -0,0 +1,245 @@
+//===-- CFG.cpp - BasicBlock analysis --------------------------------------==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This family of functions performs analyses on basic blocks, and instructions
+// contained within basic blocks.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/CFG.h"
+
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
+
+using namespace llvm;
+
+/// FindFunctionBackedges - Analyze the specified function to find all of the
+/// loop backedges in the function and return them.  This is a relatively cheap
+/// (compared to computing dominators and loop info) analysis.
+///
+/// The output is added to Result, as pairs of <from,to> edge info.
+void llvm::FindFunctionBackedges(const Function &F,
+     SmallVectorImpl<std::pair<const BasicBlock*,const BasicBlock*> > &Result) {
+  const BasicBlock *BB = &F.getEntryBlock();
+  if (succ_begin(BB) == succ_end(BB))
+    return;
+
+  SmallPtrSet<const BasicBlock*, 8> Visited;
+  SmallVector<std::pair<const BasicBlock*, succ_const_iterator>, 8> VisitStack;
+  SmallPtrSet<const BasicBlock*, 8> InStack;
+
+  Visited.insert(BB);
+  VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
+  InStack.insert(BB);
+  do {
+    std::pair<const BasicBlock*, succ_const_iterator> &Top = VisitStack.back();
+    const BasicBlock *ParentBB = Top.first;
+    succ_const_iterator &I = Top.second;
+
+    bool FoundNew = false;
+    while (I != succ_end(ParentBB)) {
+      BB = *I++;
+      if (Visited.insert(BB)) {
+        FoundNew = true;
+        break;
+      }
+      // Successor is in VisitStack, it's a back edge.
+      if (InStack.count(BB))
+        Result.push_back(std::make_pair(ParentBB, BB));
+    }
+
+    if (FoundNew) {
+      // Go down one level if there is a unvisited successor.
+      InStack.insert(BB);
+      VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
+    } else {
+      // Go up one level.
+      InStack.erase(VisitStack.pop_back_val().first);
+    }
+  } while (!VisitStack.empty());
+}
+
+/// GetSuccessorNumber - Search for the specified successor of basic block BB
+/// and return its position in the terminator instruction's list of
+/// successors.  It is an error to call this with a block that is not a
+/// successor.
+unsigned llvm::GetSuccessorNumber(BasicBlock *BB, BasicBlock *Succ) {
+  TerminatorInst *Term = BB->getTerminator();
+#ifndef NDEBUG
+  unsigned e = Term->getNumSuccessors();
+#endif
+  for (unsigned i = 0; ; ++i) {
+    assert(i != e && "Didn't find edge?");
+    if (Term->getSuccessor(i) == Succ)
+      return i;
+  }
+}
+
+/// isCriticalEdge - Return true if the specified edge is a critical edge.
+/// Critical edges are edges from a block with multiple successors to a block
+/// with multiple predecessors.
+bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
+                          bool AllowIdenticalEdges) {
+  assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!");
+  if (TI->getNumSuccessors() == 1) return false;
+
+  const BasicBlock *Dest = TI->getSuccessor(SuccNum);
+  const_pred_iterator I = pred_begin(Dest), E = pred_end(Dest);
+
+  // If there is more than one predecessor, this is a critical edge...
+  assert(I != E && "No preds, but we have an edge to the block?");
+  const BasicBlock *FirstPred = *I;
+  ++I;        // Skip one edge due to the incoming arc from TI.
+  if (!AllowIdenticalEdges)
+    return I != E;
+
+  // If AllowIdenticalEdges is true, then we allow this edge to be considered
+  // non-critical iff all preds come from TI's block.
+  while (I != E) {
+    const BasicBlock *P = *I;
+    if (P != FirstPred)
+      return true;
+    // Note: leave this as is until no one ever compiles with either gcc 4.0.1
+    // or Xcode 2. This seems to work around the pred_iterator assert in PR 2207
+    E = pred_end(P);
+    ++I;
+  }
+  return false;
+}
+
+// LoopInfo contains a mapping from basic block to the innermost loop. Find
+// the outermost loop in the loop nest that contains BB.
+static const Loop *getOutermostLoop(const LoopInfo *LI, const BasicBlock *BB) {
+  const Loop *L = LI->getLoopFor(BB);
+  if (L) {
+    while (const Loop *Parent = L->getParentLoop())
+      L = Parent;
+  }
+  return L;
+}
+
+// True if there is a loop which contains both BB1 and BB2.
+static bool loopContainsBoth(const LoopInfo *LI,
+                             const BasicBlock *BB1, const BasicBlock *BB2) {
+  const Loop *L1 = getOutermostLoop(LI, BB1);
+  const Loop *L2 = getOutermostLoop(LI, BB2);
+  return L1 != NULL && L1 == L2;
+}
+
+static bool isPotentiallyReachableInner(SmallVectorImpl<BasicBlock *> &Worklist,
+                                        BasicBlock *StopBB,
+                                        const DominatorTree *DT,
+                                        const LoopInfo *LI) {
+  // When the stop block is unreachable, it's dominated from everywhere,
+  // regardless of whether there's a path between the two blocks.
+  if (DT && !DT->isReachableFromEntry(StopBB))
+    DT = 0;
+
+  // Limit the number of blocks we visit. The goal is to avoid run-away compile
+  // times on large CFGs without hampering sensible code. Arbitrarily chosen.
+  unsigned Limit = 32;
+  SmallSet<const BasicBlock*, 64> Visited;
+  do {
+    BasicBlock *BB = Worklist.pop_back_val();
+    if (!Visited.insert(BB))
+      continue;
+    if (BB == StopBB)
+      return true;
+    if (DT && DT->dominates(BB, StopBB))
+      return true;
+    if (LI && loopContainsBoth(LI, BB, StopBB))
+      return true;
+
+    if (!--Limit) {
+      // We haven't been able to prove it one way or the other. Conservatively
+      // answer true -- that there is potentially a path.
+      return true;
+    }
+
+    if (const Loop *Outer = LI ? getOutermostLoop(LI, BB) : 0) {
+      // All blocks in a single loop are reachable from all other blocks. From
+      // any of these blocks, we can skip directly to the exits of the loop,
+      // ignoring any other blocks inside the loop body.
+      Outer->getExitBlocks(Worklist);
+    } else {
+      for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
+        Worklist.push_back(*I);
+    }
+  } while (!Worklist.empty());
+
+  // We have exhausted all possible paths and are certain that 'To' can not be
+  // reached from 'From'.
+  return false;
+}
+
+bool llvm::isPotentiallyReachable(const BasicBlock *A, const BasicBlock *B,
+                                  const DominatorTree *DT, const LoopInfo *LI) {
+  assert(A->getParent() == B->getParent() &&
+         "This analysis is function-local!");
+
+  SmallVector<BasicBlock*, 32> Worklist;
+  Worklist.push_back(const_cast<BasicBlock*>(A));
+
+  return isPotentiallyReachableInner(Worklist, const_cast<BasicBlock*>(B),
+                                     DT, LI);
+}
+
+bool llvm::isPotentiallyReachable(const Instruction *A, const Instruction *B,
+                                  const DominatorTree *DT, const LoopInfo *LI) {
+  assert(A->getParent()->getParent() == B->getParent()->getParent() &&
+         "This analysis is function-local!");
+
+  SmallVector<BasicBlock*, 32> Worklist;
+
+  if (A->getParent() == B->getParent()) {
+    // The same block case is special because it's the only time we're looking
+    // within a single block to see which instruction comes first. Once we
+    // start looking at multiple blocks, the first instruction of the block is
+    // reachable, so we only need to determine reachability between whole
+    // blocks.
+    BasicBlock *BB = const_cast<BasicBlock *>(A->getParent());
+
+    // If the block is in a loop then we can reach any instruction in the block
+    // from any other instruction in the block by going around a backedge.
+    if (LI && LI->getLoopFor(BB) != 0)
+      return true;
+
+    // Linear scan, start at 'A', see whether we hit 'B' or the end first.
+    for (BasicBlock::const_iterator I = A, E = BB->end(); I != E; ++I) {
+      if (&*I == B)
+        return true;
+    }
+
+    // Can't be in a loop if it's the entry block -- the entry block may not
+    // have predecessors.
+    if (BB == &BB->getParent()->getEntryBlock())
+      return false;
+
+    // Otherwise, continue doing the normal per-BB CFG walk.
+    for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
+      Worklist.push_back(*I);
+
+    if (Worklist.empty()) {
+      // We've proven that there's no path!
+      return false;
+    }
+  } else {
+    Worklist.push_back(const_cast<BasicBlock*>(A->getParent()));
+  }
+
+  if (A->getParent() == &A->getParent()->getParent()->getEntryBlock())
+    return true;
+  if (B->getParent() == &A->getParent()->getParent()->getEntryBlock())
+    return false;
+
+  return isPotentiallyReachableInner(Worklist,
+                                     const_cast<BasicBlock*>(B->getParent()),
+                                     DT, LI);
+}